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•i 
 
 A MANUAL 
 
 OF 
 
 DYEING AND DYEING EECEIPTS. 
 
A MANUAL 
 
 OF 
 
 DYEING AND DYEING RECEIPTS, 
 
 COMPRISING 
 
 A SYSTEM OF ELEMENTARY CHEMISTRY, 
 
 AS APPLIED TO DYEING, 
 
 WITH RECEIPTS FOR THE GENERAL READER FOR DYEING ANY 
 COLOUR ON COTTON, SILK, AND WOOL, WITH 
 COLOURED PATTERN OF CLOTH OF 
 EACH FABRIC. 
 
 JAMES NAPIER, F.R.S.E., F.C.S., &a 
 
 
 LONDON: 
 
 CHARLES GRIFFIN AND COMPANY, 
 
 10 STATIONERS’ HALL COURT. 
 
 1875 . 
 
 {All Highls Reserved.) 
 
PREFACE TO THE FIRST EDITION. 
 
 If there be any trade which, more than another, requires the knowledge 
 of first principles, it is that of dyeing, it feeing essentially progressive. 
 The particular conditions of the trade render information of this 
 description more needful, and therefore more valuable, than ordinary. 
 The trade is what is termed open, so that any man may enter it; and, 
 in consequence, there are few instances where young men are taught the 
 business systematically. A great many enter the trade who are grown 
 up,— their chief ambition being to learn the mechanical operations of the 
 dye-house, and when sufficient dexterity in these is attained, to secure 
 the highest rate of wages. When this is accomplished, zeal for im- 
 provement in a great measure subsides. However, there are many who, 
 not content with acquiring a knowledge of the mere mechanical routine, 
 desire to look deeper into the principles of the art, and aim at higher 
 honours than those of a mere labourer in it, but who believe that the 
 means of success consist simply in long and steady service, and a good 
 memory for the rules of manipulation. Both of these are valuable quali- 
 fications, but neither of them would be depreciated in the slightest 
 degree by being conjoined with a more extended knowledge of the 
 fundamental principles of the art than usually falls to the share of 
 the practical dyer. There is another evil arising out of this condition 
 of the trade. Individuals who attain the position of good workmen 
 value their abilities by the contrast which exists between them and the 
 newly-initiated journeyman; but they rarely or never look forward to 
 the wide field which lies unexplored before them. Often indeed they 
 boast of their capabilities, of their expertness, and their knowledge ; 
 and it is no uncommon thing for them to indulge in petty jealousy, 
 and endeavour to conceal the secret of their mode of working from 
 their neighbours. Under these circumstances it is no wonder that 
 years are often spent — we should say wasted — in endeavouring to dis- 
 cover what was long before patent to every one who knew the 
 
 O ^ \ 
 
viii PREFACE TO THE FIRST EDITION. 
 
 scientific principles of the trade, although ignorant of the practical 
 operations of it. This ignorance of principles often makes both work- 
 man and master the dupes of knaves who go about hawking valuable 
 secrets at so much a piece-. 
 
 It must be admitted, however, that notwithstanding all untoward 
 circumstances, the degree of advancement which the art has attained 
 is truly astonishing. A single practical hint is sometimes sufficient to 
 cause a complete revolution in some branch of the trade, so that were 
 the principles of chemistry in their application to dyeing but once 
 generally understood by those practically employed at the trade, we 
 can hardly conceive what changes and improvements might not be 
 effected. 
 
 Another circumstance calling for a few remarks is the fluctuating 
 state of the trade, which, even in its best condition, throws not less 
 than a fourth part of the workmen idle during the winter months. But 
 while we admit the hardship of such a state of things in its fullest 
 extent, we do not believe that this time should be allowed to glide by 
 in absolute listlessness. It is still a portion of the allotted span of 
 life, and ought to be turned to all the advantage which circumstances 
 will admit; and if it can be made subservient to future advantage, either 
 by advancing the personal interests, or in augmenting the mental enjoy- 
 ment of the individual, it is surely culpable to allow it to run to waste. 
 We sincerely believe that it may be turned to account in both ways, 
 and we promise, with some confidence, that the following Treatise will 
 suggest the means of deriving remuneration even from idle hours. 
 Lord Bacon’s maxim, that “ Knowledge is power,” has been reiterated 
 till it may be thought to have lost its virtue; but it is still as true as 
 
 ever, and we are confident that it cannot be more aptly applied than 
 
 to the case of the practical dyer. 
 
 From our own experience we are aware that there at present exists 
 a strong desire amongst a great many of those employed in the 
 
 processes of dyeing to understand the principles of the art, and to 
 
 be able to assign reasons for the various changes that take place in 
 producing the colours. Such knowledge is often eagerly sought for 
 without success, both in books and in the lecture-room. The dis- 
 appointment arises from two sources: first, the inability of the dyer to 
 apply chemical principles to his special purposes; and, second, a want 
 of practical knowledge in the author or lecturer, which disqualifies 
 him for pointing out the special applications of the principles he may 
 
PEEFACE TO THE FIRST EDITION. 
 
 IX 
 
 be defining. These circumstances have long impressed the Author with 
 the opinion that an application of principles to any practical operation 
 can best be done by an individual working at, or familiar with, all the 
 practical details of that particular operation or trade, and that every 
 branch of trade or art ought to have its own guide-book prepared by 
 one of its own operatives. The carrying out of this idea has induced 
 the Author to publish the present Manual, which is a “System of 
 Chemistry applied to Dyeing.” Having been himself a practical dyer for 
 many years, and having experienced the difficulties which an uneducated 
 man has to contend with in striving to become a Dyer in the proper 
 sense of the term, he has in the following pages endeavoured to clear 
 away some of the technical difficulties besetting the path of the 
 practical man, and to guide him in following out First Principles while 
 engaged in experiments to advance his art. 
 
 The Author acknowledges his obligations to a few intelligent dyers 
 for several practical hints contained in these pages, which had not 
 come under his own observation. It will also be seen in reading the 
 work, that advantage has been taken of some valuable articles in 
 foreign journals, translations of some of which have appeared in 
 chemical periodicals, such as the Pharmaceutical Times , which is now 
 discontinued, and the Chemical Gazette , a journal which he earnestly 
 recommends to the practical dyer, as containing from time to time 
 papers of great value upon Dyeing and Dye-stuffs, 
 
 Partick, Glasgow, 
 
 25 th Feb., 1853. 
 
PREFACE TO THE PRESENT EDITION. 
 
 Since the time when the Manual of Dyeing was first published, many 
 and important changes have taken place, both inside and outside the dye- 
 house. On the one hand, there is increased knowledge of the capability 
 of the art; on the other hand there is a wonderfully increased power 
 of production, resulting from improved machinery: these changes have 
 taken place inside the dye-house, while outside changes have taken place 
 also. Science has made unprecedented advances, and with its advance 
 its nomenclature has undergone an entire change. These changes and 
 additions to our knowledge have made it necessary to very carefully 
 revise and extend the Manual, in order to meet the requirements of 
 the day on its re -publication now. A short statement of the history 
 of the Manual, and the nature of the alterations now made upon it, 
 may neither be uninteresting nor out of place here. 
 
 When first published the Manual was really, if we except Dr. 
 Bancroft’s Philosophy of Permanent Colours , published in 1813, the 
 first practical Treatise on Dyeing published in this country, and as 
 the Doctor was not a dyer, the Manual was the first book upon 
 Dyeing by a practical dyer in this country. In 1842 was com- 
 menced the Glasgow Practical Mechanic and Engineer's Magazine , the 
 editor of which resolved to publish papers on different trades written 
 by practical men, and from a workman’s standpoint. I was asked 
 to furnish a few papers on Dyeing. These appeared in the years 
 1848 and 1844. Two years afterwards an American publisher printed 
 the entire series, with a little addition on calico-printing. The whole 
 formed a good-sized volume, entitled “ A Peactical Treatise on Dyeing 
 and Calico-Printing,” but neither the name of the author nor the source 
 from which the papers on Dyeing were taken was mentioned. I neverthe- 
 less felt proud that my efforts had been appreciated. In 1852 I revised 
 and extended these magazine papers, and they were issued by the 
 present firm under the title of “ A Manual of the Art of Dyeing.” 
 
PREFACE TO THE PRESENT EDITION. 
 
 xii 
 
 This work suggested to my publishers another volume more suitable 
 to the general public, containing useful receipts, which was entitled 
 “ Dyeing Receipts,” and rapidly passed into a second edition. 
 
 However, during the interval between that and the present issue 
 great changes have taken place in the Dyer’s Art, and in Chemistry. 
 At first sight those who are not engaged in the trade are apt to think 
 that the discovery and introduction of the Coal-Tar Colours has so 
 revolutionised the art, that the old dye-stuff, which it had been the 
 pride of the dyer to manipulate, has now become antiquated and has 
 been banished from the trade. However, the revolution has not been 
 so disastrous upon the old dye -drugs as appearances to the non-practical 
 man might suggest. Some few dye-stuffs have been superseded, but 
 there still remains a good assortment. Neither are the processes really 
 changed by which the dyes from these dyeing agents were produced; 
 changes in the manipulations have taken place, machinery supplying the 
 place of manual labour; but neither processes nor principles have become 
 antiquated. 
 
 Dyeing with Coal-Tar Colours is an entirely new branch of the art. 
 New matter therefore has been added under this head. I have, in treating 
 of them, kept in mind as much as possible to look at them from the stand- 
 point of the dye-house, remembering that the Manual addresses itself to 
 men who know the application of these colours, but who may understand 
 little or nothing of their chemical nature and constitution. This portion 
 of the work I have done my best to make clear, so that workmen who may 
 not have studied Chemistry to any great extent may yet understand the 
 nature of these curious compounds. 
 
 In the Chemical Formulae of the work there are great changes, and 
 those readers who are acquainted with the first edition of the Manual, and 
 who have not kept abreast with the progress of Chemistry, will be ready 
 to believe that the whole science of Chemistry has been revolutionised. In 
 the first edition indications were given of an approaching transition in the 
 manner of formulating compounds, in order to make the formulae agree 
 with the latest knowledge of the arrangement of the different elements in a 
 compound. Thus, for example, it used to be considered that acids did not 
 combine directly with a metallic element, but with its oxide, so that such 
 salts as the sulphate of iron should be sulphate of the oxide of iron, for- 
 mulated thus, S0 3 -|=FeO. I stated that this idea was giving way to the 
 idea of direct combinations with a metal*, and that the sulphate of iron 
 should be formulated thus, S0 4 -j-Fe; also, that sulphuric acid should 
 
PREFACE TO THE PRESENT EDITION. 
 
 Xlll 
 
 not be formulated as S0 3 -j-H0, but as SQ 4 -{-H, hydrogen being a 
 metallic element. Chemical discovery has necessitated greater changes 
 than these, in order that the whole science may be harmonised. 
 
 Hydrogen being the lightest element known, chemists fixed upon one 
 volume of it as the standard of comparison for the combining weight of 
 all the other elements, and whatever weight any other element combined 
 with one volume of hydrogen, that was taken to be the equivalent of 
 combination, hydrogen being one. Thus, suppose one grain of hydrogen 
 to combine with oxygen, and the compound formed would weigh 9 grains ; 
 hydrogen being one, the oxygen must therefore be eight, and this relation was 
 found to be invariable. This rule was followed with all the other elements, 
 and a table formed of the combining equivalents of all the elements. This 
 table was given in the first edition of the Manual. Afterwards, however, 
 serious objections were taken to one volume of hydrogen being regarded 
 as the standard of unity, for it necessitated anomalous conditions. Thus, 
 volume and atom being considered synonymous, if one volume — say a cubic 
 inch — was brought into combining contact with one volume of oxygen — a 
 cubic inch also— when all the hydrogen was taken up there remained 
 half of the oxygen uncombined, and it would require another cubic inch of 
 hydrogen to take up the remaining half inch of oxygen ; so that if one 
 volume or atom of hydrogen were taken as unity, then oxygen would be 
 uniting in half volumes or half atoms, which would be an absurdity, for 
 atoms being the smallest particle of matter there could be no half atoms. 
 Similar results were found in connection with many other elements. After 
 much discussion and investigation, these errors became thoroughly mani- 
 fest, and a better system was proposed by various leading chemists, 
 which came gradually into use. One volume of oxygen was taken as the 
 standard, which, retaining still the relative combining weight compared 
 with hydrogen, was called 16. Hence water, which was formerly formu- 
 lated HO, one hydrogen (1) and one oxygen (8) = 9, is now formulated 
 II 2 O, two hydrogen (2) and one oxygen (16) = 18. The equivalent 
 weights of all the other elements are taken in this relation, one volume 
 being weighed against an equal volume of oxygen. Many of these, like 
 oxygen, have their combining weights doubled, some few tripled to 
 what they were, while others remain as formerly. By comparing the 
 tables the reader will observe these changes. This change has neces- 
 sitated a considerable alteration in the formulae of compounds, to which 
 we would call the reader’s special attention. If he is in possession of 
 our former edition, and has been guided by it, he may get confused, aud 
 
XIV 
 
 PREFACE TO THE PRESENT EDITION. 
 
 think that the principles of the science are altered, which is not the case. 
 For illustration, let him examine the two tables, and take the elements of 
 nitric acid, hydrogen, nitrogen, and oxygen. The weights of the two first 
 remain as they were ; but oxygen is doubled, so that to retain the same 
 proportions we have to double the proportions of hydrogen and nitrogen. 
 
 The old formula of this acid was . . . . NO s -f- HO = 63 
 
 The transition formula was N0 6 -j- H == 63 
 
 The new formula, retaining the same proportions, would be FT 2 0 6 H 2 = 126 
 but this would not be consistent with the rule of for- 
 mulating; it is therefore divided thus, N0 3 H, formulated HNO s = 63 
 
 It will thus be observed that the original relations of the weights are 
 unaltered. I have endeavoured to make these changes as plain as possible, 
 and a very little study will enable the reader who has only been familiar 
 with the old formulae to overcome the difficulties caused by the change. 
 In the present edition I have considered myself as still addressing dyers. 
 My object in the Manual is not to teach practical Dyeing, as many of those 
 who will read this book know that better than I do; but to explain the 
 scientific principles of the art, to stimulate among working dyers a desire 
 to understand their trade, and the laws regulating the various combina- 
 tions producing the different colouring compounds, a knowledge more 
 necessary now than ever it was. This knowledge may not raise a man 
 to the position of foreman or manager ; but it will qualify him who pos- 
 sesses it for any position in connection with the trade. A knowledge of 
 principles will add interest in their work to those who labour at it, 
 removing from them the idea that they are mere labouring machines, and 
 raising them to the rank of skilled workmen — a title which, if properly 
 appreciated, would add dignity to the possessor of it. 
 
 J. N. 
 
 Partick, June , 1875. 
 
CONTENTS. 
 
 GENERAL PROPERTIES OF MATTER.— HEAT. 
 
 Conditions of Matter, .... 
 
 Heat the Cause of Conditions of Matter, 
 
 General Effects of Heat, ..... 
 
 Measures of Temperature, .... 
 
 Boiling of Liquids, ...... 
 
 Substances affecting Boiling Point, . 
 
 Strong Boiling, ...... 
 
 Chemical Effects of Heat upon Colours, 
 
 LIGHT. 
 
 Nature of Light, ...... 
 
 Relation of Colours to the Fabric, .... 
 
 Effects of Different Rays upon Colours, 
 
 Effects of Light causing Combination, 
 
 Light decomposes Chemical Compounds, 
 
 Practical Application of the Principles, 
 
 ELEMENTS OF MATTER. 
 
 Differences between an Element and Compound, 
 
 Use of Symbols, ...... 
 
 Nomenclature, ...... 
 
 Rules for Naming Compounds, .... 
 
 Salts — their Nature and Nomenclature, 
 
 CHEMICAL AFFINITY. 
 
 Application of Affinity, ..... 
 Circumstances influencing Affinity, .... 
 Catalytic Influence, .... 
 
 Constitution of Salts, ..... 
 
 Salt Radicals, ...... 
 
 PAGE 
 
 1 
 
 1 
 
 2 
 
 3 
 
 5 
 
 5 
 
 5 
 
 6 
 
 8 
 
 9 
 
 10 
 
 11 
 
 12 
 
 13 
 
 16 
 
 19 
 
 20 
 
 20 
 
 21 
 
 24 
 
 24 
 
 ~ I 
 
 25 
 
 27 
 
XVI 
 
 CONTENTS. 
 
 ELEMENTARY SUBSTANCES. 
 
 TAGK 
 
 Oxygen, ........ 29 
 
 How to make Oxygen Gas, ...... 29 
 
 Properties of Oxygen, ...... 31 
 
 Hydrogen, ........ 31 
 
 Water, ........ 32 
 
 Incrustation on Steam Boilers, ..... 38 
 
 Binoxide of Hydrogen, ...... 39 
 
 Nitrogen, ........ 39 
 
 Protoxide of Nitrogen — Nitrogen Monoxide, ... 41 
 
 Binoxide of Nitrogen — Dioxide, ..... 41 
 
 Nitrogen Trioxide, or Nitrous Acid, .... 41 
 
 Nitrogen Tetroxide, or Peroxide of Nitrogen, ... 42 
 
 Nitrogen Pentoxide, ....... 42 
 
 Nitric Acid, ........ 42 
 
 Table of the Quantity of Acid in 100 Parts by Weight, . . 46 
 
 Ammonia, ........ 48 
 
 Chlorine, ........ 49 
 
 Chlorine Protoxide, or Hypochlorous Acid, ... 50 
 
 Chlorous Acid, ..... 50 
 
 Chloric Acid, ....... 50 
 
 Perchloric Acid, ....... 51 
 
 Hydrochloric Acid, . . . . . . .51 
 
 Chloride of Nitrogen, ...... 55 
 
 Bleaching, . . . . . . . .55 
 
 Ozone, . . . . . . .71 
 
 Sulphur, 72 
 
 Sulphurous Acid, ....... 73 
 
 Sulphuric Acid, ....... 74 
 
 Hyposulphurous Acid, ...... 80 
 
 Hyposulphuric Acid, . . . . . . .81 
 
 Hydrogen Sulphide, ....... 81 
 
 Selenium, ........ 82 
 
 Phosphorus, ........ 82 
 
 Iodine, ........ 83 
 
 Bromine, ......... 84 
 
 Fluorine, . . . . . . . . 85 
 
 Silicium, ........ 85 
 
 Boron, ........ 85 
 
 Carbon, ........ 86 
 
 Carbonic Oxide, ....... 87 
 
 Carbonic Acid, ....... 88 
 
 Oxalic Acid, ........ 88 
 
 Cyanogen, ........ 89 
 
CONTENTS. xvii 
 
 METALLIC SUBSTANCES. 
 
 PAGE 
 
 General Properties of Metals, . . . . .91 
 
 Potassium, ........ 91 
 
 Potash, ........ 92 
 
 Sulphate of Potash, ....... 96 
 
 Bisulphate of Potash, ...... 96 
 
 Sulphite of Potash, . . . . . . .96 
 
 Nitrate of Potash, . . . . . . .96 
 
 Chlorate of Potash, ....... 96 
 
 Phosphate of Potash, ...... 97 
 
 Oxalate of Potash, . . . . . .97 
 
 Ferrocyanide of Potassium, ...... 97 
 
 Ferricyanide of Potassium, ...... 100 
 
 Cyanide of Potassium, ...... 101 
 
 Cyanate of Potash, ....... 101 
 
 Sodium, ........ 101 
 
 Soda, ......... 102 
 
 Soda made direct from Common Salt, .... 103 
 
 Soda-Ash, . . . . . . . 104 
 
 Sulphate of Soda, ....... 109 
 
 Chloride of Sodium, ....... 109 
 
 Nitrate of Soda, ....... 109 
 
 Borate of Soda, ....... 109 
 
 Phosphate of Soda, ....... 109 
 
 Lithium, ........ 110 
 
 Soap, ......... 110 
 
 Composition of Soaps, per 1,000 Parts, . . . .111 
 
 Barium, : . . . . . . .115 
 
 Chloride of Barium, . . . . . . .115 
 
 Nitrate of Barytes, . . . . . . .115 
 
 Strontium, . . . . . . . .115 
 
 Calcium, ........ 116 
 
 Caustic Lime, . . . . . . .116 
 
 Sulphate of Lime, . . . . . . .116 
 
 Carbonate of Lime, . . . . . . .117 
 
 Magnesium, . . * . . . . .117 
 
 Magnesia, * . . . . .117 
 
 Aluminum, . . . . . .117 
 
 Alumina, . . . . .117 
 
 Alum, . .117 
 
 Sulphate of Alumina, . .121 
 
 Acetate of Alumina, . . . • . . .121 
 
 Manganese, ........ 127 
 
 Mineral Cameleon, . . . . . . .129 
 
 b 
 
XV111 
 
 CONTENTS. 
 
 PAG* 
 
 Iron, ......... 129 
 
 Sulphate of Iron, or Ferrous Sulphate, .... 130 
 
 Chloride of Iron, ....... 135 
 
 Carbonate of Iron, ....... 135 
 
 Acetate of Iron, ....... 135 
 
 Persulphate of Iron, ....... 136 
 
 Nitrate of Iron, ....... 136 
 
 Protosalts, ........ 139 
 
 Persalts of Iron, ... ... 139 
 
 Cobalt, ........ 139 
 
 Nickel, ........ 140 
 
 Sulphate of Nickel, ....... 140 
 
 Chloride of Nickel, ....... 141 
 
 Nitrate of Nickel, ....... 141 
 
 Carbonate of Nickel, ...... 141 
 
 Zinc, ......... 141 
 
 Chloride of Zinc, ....... 142 
 
 Sulphate of Zinc, ....... 142 
 
 Nitrate of Zinc, ....... 142 
 
 Cadmium, ........ 143 
 
 Indium, ........ 143 
 
 Copper, 144 
 
 Protoxide of Copper, ...... 144 
 
 Sulphate of Copper, ....... 144 
 
 Nitrate of Copper, ....... 145 
 
 Chloride of Copper, ....... 145 
 
 Acetate of Copper, ....... 146 
 
 Oxalate of Copper, . . . . . . .146 
 
 Arseniate and the Arsenite of Copper, .... 146 
 
 Lead, ......... 146 
 
 Sub oxide of Lead, ....... 147 
 
 Protoxide of Lead, ....... 147 
 
 Peroxide of Lead, . . . . . . .148 
 
 Carbonate of Lead, ....... 148 
 
 Nitrate of Lead, ....... 148 
 
 Acetate of Lead, ....... 148 
 
 Sulphate of Lead, ... ... 150 
 
 Chloride of Lead, ....... 150 
 
 Testing the Value of Lead Salts, ..... 151 
 
 Thallium, ........ 151 
 
 Bismuth, ........ 151 
 
 Nitrate of Bismuth, ....... 152 
 
 Tin, ......... 152 
 
 Protoxide of Tin, or Stannous Oxide, .... 153 
 
 Protochloride of Tin, ...... 154 
 
CONTENTS. 
 
 XIX 
 
 PAGE 
 
 Protosulphate of Tin, ...... 154 
 
 Protonitrate of Tin, . . . . . . .155 
 
 Tartrate of Potash and Tin, ...... 155 
 
 Deutoxide, or Sesquioxide of Tin, ..... 155 
 
 Peroxide of Tin, ....... 156 
 
 Perchloride of Tin — Stannic Chloride, .... 156 
 
 Spirits, ........ 158 
 
 Red Spirits, ........ 158 
 
 Plumb Spirits, ....... 159 
 
 Barwood Spirits, 159 
 
 Yellow Spirits, ....... 159 
 
 Acetate of Tin, ....... 159 
 
 Oxalate of Tin, ....... 159 
 
 Stannate of Soda, . . . . . . .160 
 
 Titanium, ........ 162 
 
 Chromium, ...... . 162 
 
 Chloride of Chromium, ...... 163 
 
 Sulphate of Cromium, . . . . . .163 
 
 Chromic Acid, . . . . . . .164 
 
 Bichromate (Red Chromate) of Potash, .... 165 
 
 Chromate of Lead, . . . . . . .166 
 
 Chrome Yellow, ....... 166 
 
 Chrome Greens, ....... 168 
 
 Chrome Orange, . . . . . . . 168 
 
 Tests for Bichromate of Potash, . . . . .169 
 
 Vanadium, ........ 170 
 
 Tungstenum, or Wolfram, ...... 170 
 
 Molybdenum, ....... 171 
 
 Peroxide of Molybdenum, . . . . . .171 
 
 Molybdic Acid, . . . . . . .171 
 
 Tellurium, ........ 172 
 
 Tellurous Acid, ....... 172 
 
 Telluric Acid, . . . . . . .172 
 
 Arsenic, ........ 172 
 
 Arsenious Acid, ....... 173 
 
 Arsenic Acid, . . . . . . .174 
 
 Sulphides of Arsenic, . . . . .174 
 
 Antimony, ........ 175 
 
 Oxide of Antimony, . . . . . . .175 
 
 Sulphate of Antimony, ...... 176 
 
 Antimonious Acid, . , . . . .176 
 
 Antimonic Acid, . . .176 
 
 Uranium, ........ 176 
 
 Protoxide of Uranium, .177 
 
 Peroxide of Uranium, .177 
 
XX 
 
 CONTENTS, 
 
 PAGE 
 
 Cerium, ....... 
 
 178 
 
 Mercury, ....... 
 
 178 
 
 Suboxide of Mercury, ..... 
 
 178 
 
 Protoxide of Mercury, Peroxide of Mercury, or Red Oxide, 
 
 178 
 
 Silver, ■ . 
 
 179 
 
 Nitrate of Silver, ...... 
 
 180 
 
 Sulphate of Silver, ...... 
 
 180 
 
 Gold, 
 
 181 
 
 Chloride of Gold, ...... 
 
 181 
 
 Perchloride or Trichloride of Gold, .... 
 
 182 
 
 Platinum, ....... 
 
 182 
 
 Palladium, ....... 
 
 183 
 
 Iridium, ....... 
 
 184 
 
 Osmium, ....... 
 
 184 
 
 Rhodium, ....... 
 
 184 
 
 Lanthanium, ....... 
 
 185 
 
 MORDANTS. 
 
 
 Red Spirits, ....... 
 
 196 
 
 Barwood Spirits, ...... 
 
 197 
 
 Plumb Spirits, ...... 
 
 197 
 
 Yellow Spirits, ...... 
 
 198 
 
 Nitrate of Iron, ...... 
 
 198 
 
 Acetate of Iron and Alumina, .... 
 
 199 
 
 Acetate of Alumina, ..... 
 
 199 
 
 Black Iron Liquor, ...... 
 
 199 
 
 Iron and Tin for Royal Blue, .... 
 
 199 
 
 Acetate of Copper, ...... 
 
 199 
 
 VEGETABLE MATTERS USED IN DYEING. 
 
 Introductory Remarks, ...... 206 
 
 Galls, ........ 213 
 
 Sumach, ........ 220 
 
 Catechu, ........ 224 
 
 Valonia Nuts, ....... 227 
 
 Divi Divi, ........ 227 
 
 Myrobalans, ........ 227 
 
 INDIGO. 
 
 Woad and Pastel, 
 Indigo Blue, . 
 Pastel Vat, 
 
 257 
 
 257 
 
 259 
 
CONTENTS. 
 
 XXI 
 
 PAGE 
 
 Woad Yat, . . 261 
 
 Modified Pastel Yat, ....... 262 
 
 Indian Yat, ........ 263 
 
 Potash Yat, ........ 264 
 
 German Yat, ........ 264 
 
 Management of the Yats, ...... 265 
 
 Logwood, ........ 269 
 
 Brazil-Woods, ....... 276 
 
 Santal or Sandal-Wood, . . . . . 279 
 
 Barwood, ........ 280 
 
 Camwood, ........ 282 
 
 Fustic or Yellow -Wood, ...... 283 
 
 Young Fustic, ....... 284 
 
 Bark or Quercitron, ....... 285 
 
 Flavine, ........ 287 
 
 Weld or Wold, ....... 288 
 
 Turmeric, ........ 289 
 
 Persian Berries, ....... 289 
 
 Safflower or Carthamus, ...... 290 
 
 MADDER. 
 
 Levant Madder, ....... 294 
 
 Dutch Madder, ....... 295 
 
 Alcase Madder, ....... 295 
 
 Madder of Avignon, ....... 295 
 
 Madder Purple, ....... 298 
 
 Madder Red, . ....... 298 
 
 Madder Orange, ....... 299 
 
 Madder Yellow, ....... 299 
 
 Madder Brown, ....... 299 
 
 Madder Acids, ....... 299 
 
 Madder Preparations, ...... 300 
 
 Munjeet, or Mungeet, ...... 303 
 
 Annotta, or Arnotto, ...... 803 
 
 Alkanet Root, ....... 306 
 
 Archil, or Orchil, ....... 806 
 
 Sooranjee, ........ 308 
 
 Carajuru, or Chica, . . . . . . .311 
 
 Wongshy, ........ 312 
 
 Aloes, ........ 315 
 
 Pittacal, ........ 316 
 
 Barbary Root, . . . . .317 
 
 Cochineal, . . . 318 
 
 Carmine, ........ 819 
 
xxii CONTENTS. 
 
 PAG* 
 
 Lake Lake, or Lac, ....... 322 
 
 Kerms. ........ 323 
 
 Ultramarine, ........ 323 
 
 COAL-TAR COLOURS. 
 
 Greens, ........ 331 
 
 DYEING RECEIPTS. 
 
 Introductory Observations, ...... 338 
 
 PRELIMINARY PREPARATIONS FOR DYEING. 
 
 1. Banding, ........ 339 
 
 2. Boiling and Sticking, ...... 339 
 
 3. Cotton Cloth, . . . . . . . 339 
 
 4. To remove Oil Stains, ...... 340 
 
 5. To remove Iron Stains, ...... 340 
 
 6. To make Bleaching Liquor, ..... 340 
 
 7. To bleach Cotton Yarn for Dyeing, .... 340 
 
 8. To work Cotton Yarn for Dyeing or Bleaching for Dyeing, . 341 
 
 9. To bleach Cotton Yarn to be finished White, . . . 341 
 
 10. To bleach Cotton Cloth, ..... 341 
 
 11. To make Caustic Potash, ..... 341 
 
 12. To make Caustic Soda, ...... 342 
 
 13. To slake Lime, ....... 342 
 
 14. To make a Sour, ....... 342 
 
 15. To make Nitrate of Iron, ..... 342 
 
 16. To make Acetate of Iron, ..... 342 
 
 17. To make Sulphate of Iron, ..... 343 
 
 18. To make Proto -Chloride of Iron, .... 343 
 
 19. To make Persulphate of Iron, ..... 343 
 
 20. Other Methods, ....... 343 
 
 21. To make Perchloride of Iron, ..... 343 
 
 22. To make Sulphate of Zinc, ..... 344 
 
 23. To make Sulphate of Copper, ..... 344 
 
 24. To make Nitrate of Copper, ..... 344 
 
 25. To feather Tin or Zinc, . . . . . . 344 
 
 26. Protochloride of Tin, ...... 344 
 
 27. To make Bichloride of Tin, ..... 345 
 
 28. Another Method for Permuriate of Tin, . . . 345 
 
 29. Red Spirits, ....... 345 
 
CONTENTS. 
 
 XX1U 
 
 PAGE 
 
 30. To make Yellow Spirits, 
 
 
 . 
 
 345 
 
 31. Barwood Spirits, .... 
 
 
 
 345 
 
 32. Spirit Mordant for Woollen, 
 
 
 
 345 
 
 33. Plumb Spirits, ..... 
 
 
 
 346 
 
 34. Double Muriate of Tin, .... 
 
 
 
 346 
 
 35. Single Muriate of Tin, .... 
 
 
 
 346 
 
 36. To make a Plumb Tub, .... 
 
 
 
 346 
 
 37. Alum Plumb Tub, .... 
 
 
 
 346 
 
 38. Peachwood Plumb, .... 
 
 
 
 346 
 
 39. To make up a Blue Vat, 
 
 
 
 346 
 
 39a. Another Method, .... 
 
 
 
 347 
 
 40. To prepare Annotta, .... 
 
 
 
 347 
 
 41. To prepare Catechu, .... 
 
 
 
 347 
 
 42. To make Decoctions of Ground Woods, 
 
 43. To test the Comparative Quality of Logwood, or other Vegetable 
 
 347 
 
 Colouring Matters Soluble in Water, . 
 
 
 
 347 
 
 44. To make Sulphate of Indigo, 
 
 
 
 348 
 
 45. To prepare Indigo Extract, 
 
 
 
 348 
 
 46. To make Sour Extract of Indigo, 
 
 
 
 348 
 
 47. To make Free Extract of Indigo, 
 
 
 
 348 
 
 48. To make Chemic, .... 
 
 
 
 349 
 
 49. To prepare Safflower for Dyeing Cotton, 
 
 
 
 349 
 
 50. To prepare Safflower for Dyeing Silk, . 
 
 
 
 349 
 
 51. To make Oxalate and Muriate of Tin, . 
 
 
 
 349 
 
 52. To make Acetate of Alumina, 
 
 
 
 350 
 
 53. To test Water, ..... 
 
 
 
 350 
 
 54. To make Lime-Water, .... 
 
 
 
 350 
 
 55. To make Cochineal Liquor, or Paste, 
 
 
 
 351 
 
 56. To remove Mildew from Cotton, 
 
 
 
 351 
 
 57. To remove Indelible Ink Marks, 
 
 
 
 351 
 
 58. Another Method, .... 
 
 
 
 351 
 
 59. To detect Animal and Vegetable Fibres, 
 
 
 
 351 
 
 60. To detect Mixed Fabrics of Cotton and Wool, 
 
 
 
 351 
 
 61. To detect Cotton in Linen, 
 
 
 
 351 
 
 62. Another Method for detecting Cotton in Linen, 
 
 
 
 352 
 
 63. Cotton and Wool, .... 
 
 
 
 352 
 
 64. Cotton with Silk and Wool, 
 
 
 
 352 
 
 65. Cotton with Silk and Woollen, . 
 
 
 
 352 
 
 66. Softening, . .... 
 
 
 
 852 
 
 67. To strip Royal Blue from Silk or Woollen, 
 
 
 
 862 
 
 68. Strip Scarlet Cochineal Dye, 
 
 
 
 353 
 
 69. To make Soluble Prussian Blue for Domestic Use, 
 
 
 
 353 
 
 70. Another Method, .... 
 
 
 
 353 
 
 71. To find the Quantity of Tannin in any Vegetable, 
 
 
 
 853 
 
 71a. Testing Dyed Stuffs or Fibres, . 
 
 
 
 353 
 
XXIV 
 
 CONTENTS. 
 
 COTTON DYEING. 
 
 PAGE 
 
 General Directions, . . . . . . 356 
 
 72. Black, 357 
 
 73. Jet Black, ....... 357 
 
 74. Blue Black, ....... 358 
 
 75. Spirit Brown, ....... 358 
 
 76. Mordant Brown, ...... 358 
 
 77. Cinnamon Brown, ...... 358 
 
 78. Uvanterine Brown, ...... 359 
 
 79. Fawn Brown, ....... 359 
 
 80. Bismarck Brown, ...... 359 
 
 81. Catechu Brown, ...... 359 
 
 82. Catechu Chocolates, ...... 360 
 
 83. Chocolate or French Brown, ..... 360 
 
 84. Catechu Fawns, . . . . . .360 
 
 85. Catechu Fawns — Another Method, .... 360 
 
 86. Catechu Fawns — Another Method, .... 361 
 
 87. Safflower Pink, ...... 361 
 
 88. Bose Colour, . . . . . . . 361 
 
 89. Safflower Crimson, ...... 362 
 
 90. Safflower Bed, ....... 362 
 
 91. Safflower Scarlet, ...... 362 
 
 92. Aniline Pink, ....... 362 
 
 93. Common Bed, ....... 362 
 
 94. Barwood Bed, ....... 363 
 
 95. Aniline Bed, ....... 363 
 
 96. Common Crimson, . . . . . .364 
 
 97. Magenta, ....... 364 
 
 98. Light Straw, . . . . . . .364 
 
 99. Leghorn, . . . . . . .364 
 
 100. Lemon Yellow, . . . . . . .364 
 
 101. Chrome Yellow, ...... 365 
 
 102. Chrome Amber, . . . . . .365 
 
 103. Another Method for Dark Yellows, .... 365 
 
 104. Spirit Yellow, ....... 366 
 
 105. Light Spirit Yellow, ...... 366 
 
 106. Bark Yellow with Mordant, ..... 366 
 
 107. Chrome Orange, ...... 366 
 
 108. Another Method for Chrome Orange, .... 367 
 
 109. Annotta Orange, ...... 367 
 
 110. Sky Blue or Prussian Blue, ..... 367 
 
 111. Napoleon Blue, ...... 368 
 
 112. Boyal Blue, ....... 368 
 
 113. China Blue, ....... 368 
 
 114. Opal or Spirit Blue, ...... 369 
 
CONTENTS. 
 
 XXV 
 
 PAGE 
 
 115. Logwood Blue, ...... 369 
 
 116. Indigo Vat Blue, ...... 369 
 
 117. Chrome Green, ...... 370 
 
 118. Bark Green on Yarn, ...... 370 
 
 119. Fustic Green on Yarn, . . . . . .370 
 
 120. Bark or Chemic Green on Cloth, . . . .370 
 
 121. Fustic Green on Cloth, . . . . .371 
 
 122. Green with Prussian Blue, ..... 371 
 
 123. Sage Green, . . . . . . .371 
 
 124. Olive or Bottle Green, ..... 372 
 
 125. Olive or Bottle Green — Another Method, . . . 372 
 
 126. Deep Olive Green, ...... 372 
 
 127. Aniline Green, ....... 372 
 
 128. Lavender Puce or Lilac, ..... 373 
 
 129. Another Method, ...... 378 
 
 130. Light Purple or Adelaide, ..... 373 
 
 131. Another Method and Deeper Shade, .... 373 
 
 132. Ordinary Purple, ...... 374 
 
 133. Lavender or Peach, ...... 374 
 
 134. Logwood Puce, ...... 374 
 
 135. Another Method, . . . . . .374 
 
 136. Light Lavender, ...... 374 
 
 137. Aniline Purple, ...... 375 
 
 138. Mauve, ........ 375 
 
 139. Aniline Lavender, . . . . . .375 
 
 140. French White, ...... 375 
 
 141. Safflower Lavender, ...... 375 
 
 142. Safflower Lavender — Another Method, . . .376 
 
 143. Iron Buff or Nankeen, ...... 376 
 
 144. Another Method, ...... 376 
 
 145. Another Method, . . . . . . 377 
 
 146. Drab, ........ 377 
 
 147. Olive Drab, ....... 377 
 
 148. Rich Reddish Drab, . . . . . .377 
 
 149. Stone Colour, ....... 377 
 
 150. Catechu Stone Drab, ...... 378 
 
 151. Catechu Drab, ....... 378 
 
 SILK DYEING. 
 
 Preliminary Remarks, . . . . . .379 
 
 152. Black, ........ 379 
 
 153. Full Deep Black, ..... 380 
 
 154. French Black, ....... 380 
 
 155. Blue Black by Prussiate, ..... 380 
 
XXVI 
 
 CONTENTS. 
 
 PAGE 
 
 156. Deep Hat Black, or Paris Black, .... 380 
 
 157. Mixed Black, ....... 380 
 
 158. Brown, ..... . 381 
 
 159. Brown, ........ 381 
 
 160. Red Browns, ....... 381 
 
 161. Another Method, ...... 382 
 
 162. Chocolate Brown, . .... 382 
 
 163. Bronze Brown, ... ... 382 
 
 164. Another Method, ... . . 382 
 
 165. Safflower Pink, ....... 382 
 
 166. Safflower Rose and Crimson, ..... 383 
 
 167. Safflower Scarlet, ...... 383 
 
 168. Cochineal Crimson, ...... 383 
 
 169. General Remarks, ...... 384 
 
 170. Aniline Pink, 384 
 
 171. Aniline Red, 384 
 
 172. Common Red, ...... 385 
 
 173. Cochineal Pink, ...... 385 
 
 174. Cochineal Scarlet, . . ... 385 
 
 175. Common Crimson, ...... 385 
 
 176. Common Scarlet, ...... 385 
 
 177. Rubies, Maroons, &c., ...... 335 
 
 178. Rubies, &c., 386 
 
 179. Sky Blue, 386 
 
 180. Prussian Blue — Sky, . ... 386 
 
 181. Royal Blue, ....... 386 
 
 182. Another Method, or Napoleon Blue, .... 387 
 
 183. Alkaline Blue, ....... 387 
 
 184. Aniline Blue, ....... 388 
 
 185. Lavender, ....... 388 
 
 186. Lavender — Another Method, ..... 388 
 
 187. Wine Colour, Violet, Lilac, &c., .... 388 
 
 188. Violet, ........ 389 
 
 189. Hofmann’s Violet, ...... 389 
 
 190. French and Pearl White, ..... 389 
 
 191. Another Method, ...... 389 
 
 192. Weld, Yellow, ....... 389 
 
 193. Bark and Fustic Yellow, ..... 390 
 
 194. Another Method, ...... 390 
 
 195. Gold and Amber, ...... 390 
 
 196. Nankeen, Buff, Salmon, Flesh, &c., .... 390 
 
 197. Orange, ........ 390 
 
 198. Orange — Another Method, ..... 391 
 
 199. Yellow Drab, ....... 391 
 
 200. Common Drabs, ...... 391 
 
CONTENTS. xxvii 
 
 PAGE 
 
 201. Slate or Stone Colour, ...... 391 
 
 202. Common Green, ...... 392 
 
 203. Another Method, ...... 392 
 
 204. Sage Green and Pea Green, ..... 392 
 
 205. Bottle Green, ....... 393 
 
 206. Another Method, ...... 393 
 
 207. Green, ........ 393 
 
 208. Another Method, ...... 393 
 
 209. Olive, 393 
 
 210. Light Olive, 394 
 
 WOOLLEN DYEING. 
 
 Preliminary Remarks, ...... 395 
 
 211. Black, ........ 395 
 
 212. Black, ........ 395 
 
 213. Blue Black, ....... 396 
 
 214. Common Black, . ..... 396 
 
 215. Brown, ........ 396 
 
 216. Chrome Brown, ...... 396 
 
 217. Yellow or Light Brown, .... 397 
 
 218. Brown, ........ 397 
 
 219. Brown, ........ 397 
 
 220. Madder Brown, ....... 397 
 
 221. Crimson, ....... 397 
 
 222. Magenta, . . . . . . .398 
 
 223. Scarlet, ........ 398 
 
 224. Another Method, ...... 398 
 
 225. Red, ........ 398 
 
 226. Lac -Scarlet or Red, ...... 398 
 
 227. Claret, ........ 398 
 
 228. Madder Red, ....... 399 
 
 229. Pink, ........ 399 
 
 230. Pink, ' . . . . . . . .399 
 
 231. Yellow, ........ 399 
 
 232. Yellow or Amber, ...... 399 
 
 233. Another Method, ...... 400 
 
 234. Another Method for Yellow, ..... 400 
 
 235. Orange, ....... 400 
 
 236. Sky Blue, ....... 400 
 
 237. Aniline Blue, ....... 400 
 
 238. Royal Blue, ....... 401 
 
 239. Another Method, ...... 401 
 
 240. Saxon Blue, ....... 401 
 
 241. Pigeon Blue, ....... 401 
 
XXV111 
 
 CONTENTS. 
 
 PAGE 
 
 242. Another Method, ...... 401 
 
 243. Oak or Apple Green, ...... 402 
 
 244. Common Logwood Green, ..... 402 
 
 245. Common Green, ...... 402 
 
 246. Fast Green, ....... 402 
 
 247. Bottle Green, ....... 402 
 
 248. Invisible Green, ...... 403 
 
 249. Grass Green, ....... 403 
 
 250. Olive, ........ 403 
 
 251. Olive, ........ 403 
 
 252. Purple, . . . . . . . . 403 
 
 253. Hofmann’s Violet, ...... 404 
 
 254. Peach, to Wine Colour, . . . . . 404 
 
 255. Light Violet, ....... 404 
 
 256. Perkin’s Mauve Original Colour, .... 404 
 
 257. Common Puce, ....... 405 
 
 258. Puce or Purple, ...... 405 
 
 259. Greenish Drab, ....... 405 
 
 260. Brown Drab, ....... 405 
 
 261. Light Grey, ....... 405 
 
 262. Grey Drab, ....... 406 
 
 263. Another Method, ...... 406 
 
 264. Slate Drab, ....... 406 
 
 265. Slate or Stone Colour, ...... 406 
 
 266. Blue by Woollen Blue Vat, . . . . 407 
 
 267. Another Blue Vat for W'oollen, .... 407 
 
 MIXED FABRICS— DYED TWO COLOURS. 
 
 268. Green and Pink, ...... 408 
 
 269. Green and Crimson, ...... 493 
 
 270. Blue and Orange, ...... 408 
 
 MIXED FABRICS— DYED ONE COLOUR. 
 
 271. Black on Cotton and Woollen, . 410 
 
 272. Brown on Cotton and Woollen by one Process, . . 410 
 
 273. Black on Silk and Woollen by one Process, . . . 410 
 
 274. Black on Cotton, Silk, and Woollen, by one Process, . 410 
 
 275. Drabs on Cotton, Silk, and Woollen, by one Process, . 410 
 
 Colour and Dress, .... . 411 
 
 Glossary of Technical Terms, . . . . . 413 
 
 Index, . . . . . . . .417 
 
DYEING. 
 
 GENERAL PROPERTIES OF MATTER. 
 
 HEAT. 
 
 Conditions of Matter. — Matter, which is everything capable of affecting 
 the senses, exists in three different states, — solid, fluid, and gaseous. 
 Looking upon matter in any of these states, the most casual observer 
 cannot fail to distinguish a great variety of appearances. For example, 
 stone differs from brick, bread from wood, and iron from both, among 
 the solid forms ; while differences quite as great are seen both in fluids 
 and amongst gases. But although these differences are familiar to all, 
 there are few who inquire the cause why, under the same circumstances, 
 one portion of matter exists as a solid, another as a fluid, and a third as 
 a gas. Correct answers to these inquiries are the objects of scientific 
 research. They are in their nature twofold — physical and chemical. The 
 former, embracing the study of matter in mass , takes cognisance of shape, 
 measure, hardness, weight, flexibility, tenacity, divisibility, and such like 
 properties; while the latter, the chemical, investigates those more remote 
 differences which depend on the relative powers, properties, and mutual 
 actions of the elemental components of the given substance an inquiry 
 which embraces a universal interrogation of all kinds of matter. 
 
 Heat the Cause of Conditions of Matter.— That one body is solid, 
 another fluid, and a third gaseous, is an inquiry which belongs more 
 directly to physics than to chemistry; yet heat, which is the cause of 
 these differences, is so intimately connected both with the molecular 
 changes and the constitution of bodies, particularly of the colouring 
 matters used in dyeing, that it will be proper to enumerate, preliminarily, 
 a few of its most prominent effects and general laws, for convenience of 
 frequent reference when we come to speak of the practical effects of those 
 laws on many of the operations in the dye-house. 
 
 All bodies are supposed capable of existing in the three states solid, 
 fluid, and gaseous— by the addition or subtraction of heat; but the 
 same degree of heat does not affect all kinds of bodies to the same extent. 
 For example, water subject to the ordinary pressure of the atmosphere, at 
 32° Fah. and under is solid, from 32° to 212° it is fluid, and from 212® 
 upwards it is gaseous ; while quicksilver, another fluid, at the ordinary 
 
 A 
 
2 
 
 GENERAL EFFECTS OF HEAT. 
 
 temperature does not become solid until it is cooled 72° below that of the 
 solidifying point of water, and does not pass into the gaseous state until 
 it is heated upwards of 400° above the aeriform point of water. Again, 
 lead and several other bodies only become fluid at the temperature which 
 gasifies quicksilver. The following table will make this more apparent: — 
 
 
 Solid 
 
 Becomes 
 
 Becomes 
 
 Range of 
 
 
 under 
 
 fluid at 
 
 gaseous at 
 
 fluidity. 
 
 Sulphurous Acid, 
 
 . -105 
 
 105 
 
 14 
 
 91 
 
 Carbonic Acid, 
 
 . -71 
 
 None. 
 
 71 
 
 None. 
 
 Mercury, 
 
 . -39 
 
 39 
 
 622 
 
 701 
 
 Water, 
 
 32 
 
 32 
 
 212 
 
 180 
 
 Tin, 
 
 . 442 
 
 442 about 2400 about 2058 
 
 Lead, 
 
 . 600 
 
 594 
 
 Not known. 
 
 
 Bismuth, . 
 
 . 500 
 
 500 
 
 900 
 
 400 
 
 Arsenic, . 
 
 . 356 
 
 None. 
 
 356 
 
 None. 
 
 Silver, 
 
 : 2283 
 
 2283 
 
 Not known. 
 
 
 Cast Iron, 
 
 . 3479 
 
 3479 
 
 Not known. 
 
 
 This table shews how differently the same degree of heat affects different 
 substances. We cannot conceive a condition so cold that all matter would 
 be solid, nor so hot that all would be gaseous. In the cases of carbonic 
 acid and arsenic, there appears an exception : these bodies have no fluid 
 range — they have no known existence in a fluid state. The former may 
 be obtained fluid by pressure ; but this is under extraordinary circum- 
 stances, and the particles still retain their elasticity, which a true fluid 
 does not. But when in the -solid state, and under ordinary conditions — 
 that is, under the ordinary pressure of the atmosphere — it passes directly 
 from the solid to the gaseous state on the temperature being raised. 
 
 Some philosophers, reasoning from analogy, and not admitting any 
 exceptions to what are considered general laws in nature, object to the 
 apparent fact, and give, as their opinion, that such substances as carbonic 
 acid really have a fluid range; but being so little, probably only a few 
 degrees, the body may pass through that state without observation. 
 There are many other bodies, besides carbonic acid and arsenic, that 
 require a greater amount of pressure than that of our atmosphere to 
 maintain them in the fluid state, so that both the facts and the circum- 
 stances are in accordance with the general laws of nature. 
 
 General Effects of Heat. — In connection with the general laws of 
 heat, we may notice, first, that bodies when they become heated expand, 
 or become larger — the particles which compose them seem to separate farther 
 from one another. Familiar illustrations of this effect of heat are numerous. 
 If a pair of tongs, with legs of equal length, have one of the legs put into 
 the fire and made red hot, it will be found, in this state, longer than the 
 other. It is well known to dyers that if a boiler be filled to within a 
 little of the mouth with cold water, and a fire put under it, by the time 
 
MEASURES OF TEMPERATURE. 
 
 3 
 
 it begins to boil the water runs over, having enlarged so much that the 
 boiler is too small to contain it when hot. Another circumstance often 
 occurs — when a certain quantity of a decoction of a dye is required, and 
 is measured out of the boiler in gross while hot, and then distributed in 
 the same proportions when cold, there is wanting a considerable portion 
 of liquid at the end, causing serious annoyances in the dye-house, when 
 the contraction and expansion by temperature are not taken into con- 
 sideration. 
 
 That gaseous bodies are affected in the same way by heat, may be 
 illustrated by taking a bladder, and filling it three parts full with cold 
 air, tying it round the neck, and holding it before a fire — or, what is 
 better, taking the bladder into the drying-stove connected with the dye- 
 house. In a very little time the bladder becomes distended and quite 
 full, and may be made to burst by the expansion of the air, if the heat be 
 high, or the bladder originally nearly filled. 
 
 Measures of Temperature. — Upon this expansive effect of heat is 
 founded the means of measuring its intensity. Our senses tell us when a 
 body is hot or cold, but they are very imperfect indicators of the degree 
 or intensity of the heat. Our own temperature being the standard, we 
 can only tell that a substance is hotter or colder than our own body. In 
 the dye-house, where the hand is often made the indicator of the tempera- 
 ture of the dyeing liquid, the result varies according to whether the person 
 has been previously working in hot or cold liquids, and is therefore a very 
 imperfect test of temperature, and often productive of evils by giving 
 different tints of shades, and deteriorating the beauty of a colour. Tem- 
 perature is very correctly measured by observing the amount of expansion 
 in any given body. Instruments for this purpose are plentiful and cheap : 
 we will therefore not require to detail their mode of manufacture; but a 
 good thermometer is an essential instrument in the dye-house, and ought 
 to be constantly employed. The thermometers used in this country are 
 generally those of Fahrenheit. The scale of measurement of this has 
 been determined in the following manner: — Fahrenheit divided the two 
 points, from the freezing of water to its boiling, into 180 degrees: he 
 called the freezing point the 32nd degree, from some reason of his own; 
 hence 32° + 180° =212, the boiling point of water, according to Fahren- 
 heit. There is another scale sometimes used, called Reaumur’s. This has 
 the two points, from the freezing to the boiling of water, divided into 80 
 degrees. Another, and more generally used scale, has the range from 
 freezing point to boiling of water, divided into 100 degrees; thus the 
 freezing point is marked 0, the boiling point 100. This is termed the 
 Centigrade thermometer. In reading books where temperature is referred 
 to — such as in many dyeing recipes and processes — attention must be paid 
 which thermometer scale is referred to. They are generally indicated by 
 abbreviations — as F. or Fah., for Fahrenheit’s scale, It. or Reau., for 
 Reaumur’s, and C. for the Centigrade. The following table of the corn- 
 
4 
 
 MEASURES OF TEMPERATURE. 
 
 parative value of the different scales, of Centigrade and Fahrenheit, will 
 guide the operator in using one Or other of them : — 
 
 Cent. 
 
 Fah. 
 
 Cent. 
 
 Fah. 
 
 Cent. 
 
 Fah. 
 
 0 
 
 ....32 
 
 34 
 
 .... 93-2 
 
 68 
 
 ....154-4 
 
 1 
 
 ....33-8 
 
 35 
 
 .... 95 
 
 69 
 
 ....156-2 
 
 2 
 
 ....35-6 
 
 36 
 
 .... 96-8 
 
 70 
 
 ....158 
 
 3 
 
 ....37-4 
 
 37..... 
 
 .... 98-6 
 
 71 
 
 ....159-8 
 
 4 
 
 ....39-2 
 
 38 
 
 ....100-4 
 
 72 
 
 ....161-6 
 
 5 
 
 ....41 
 
 39 
 
 ....102-2 
 
 73 
 
 ....163-4 
 
 6.... 
 
 ....42-8 
 
 40 
 
 ....104 
 
 74 
 
 165-2 
 
 7 
 
 ....44-6 
 
 41 
 
 ....105-8 
 
 75 
 
 ,...167 
 
 8.... 
 
 ....46-4 
 
 42 
 
 ....107-6 
 
 76 
 
 ....168 8 
 
 9 
 
 ....48*2 
 
 43 
 
 ....109-4 
 
 77 
 
 ,...170-6 
 
 10 
 
 ....50 
 
 44 
 
 ....111-2 
 
 78 
 
 ,...172-4 
 
 11.... 
 
 . ..51-8 
 
 45...:. 
 
 ....113 
 
 79 
 
 ....174-2 
 
 12 
 
 ....53*6* 
 
 46 
 
 ....114-8 
 
 80 
 
 ,...176 
 
 13 
 
 55*4 
 
 47 
 
 ....116-6 
 
 81 
 
 177-8 
 
 14 
 
 57-2 
 
 48 
 
 ....118-4 
 
 82 
 
 179-6 
 
 15 
 
 59 
 
 49 
 
 ....120-2 
 
 83 
 
 181-4 
 
 16 
 
 60-8 
 
 50.. .. 
 
 ....122 
 
 84 
 
 183-2 
 
 17 
 
 ....62-6 
 
 51 
 
 ....123-8 
 
 85 
 
 185 
 
 18 
 
 64-4 
 
 52 
 
 ....125-6 
 
 86 
 
 186-8 
 
 19 
 
 66-2 
 
 53 
 
 ....127-4 
 
 87 
 
 188-6 
 
 20 
 
 68 
 
 54..... 
 
 ....129-2 
 
 88 
 
 190-4 
 
 21 
 
 69-8 
 
 55..... 
 
 ....131 
 
 89 .... 
 
 192-2 
 
 22...., 
 
 71-6 
 
 56 
 
 132-8 
 
 90 
 
 194 
 
 23 
 
 73-4 
 
 57 
 
 134-6 
 
 91 
 
 195-8 
 
 24 
 
 75-2 
 
 58 
 
 136-4 
 
 92.... 
 
 197-6 
 
 25 
 
 77 
 
 59 
 
 138-2 
 
 93.... 
 
 199-4 
 
 26.... 
 
 78-8 
 
 60 
 
 ,. ,.140 
 
 94.... 
 
 201-2 
 
 27.... 
 
 80-6 
 
 61 
 
 141-8 
 
 95.... 
 
 203 
 
 28.... 
 
 82-4 
 
 62 
 
 143-6 
 
 96.... 
 
 204-8 
 
 29.... 
 
 84-2 
 
 63 
 
 .....145-4 
 
 97.... 
 
 206-6 
 
 30.... 
 
 86 
 
 64 
 
 147-2 
 
 98.... 
 
 208-4 
 
 31.... 
 
 87-8 
 
 65 
 
 149 
 
 99.... 
 
 210-2 
 
 32.... 
 
 89-6 
 
 66.... 
 
 150-8 
 
 100.... 
 
 212-0 
 
 33.... 
 
 91-4 
 
 67 
 
 152-6 
 
 
 
 It will be seen from this table that every 5 degrees of the Centigrade 
 scale is equal to 9 Fahrenheit ; so that any degree of the one may be con- 
 verted into the other by a simple rule — namely, by multiplying the 
 Centigrade by 9, and dividing by 5, then adding 32°. Thus, if any 
 liquid is recommended to be at 60° C., then 60° Cent. X 9 5 -f- 32° = 
 
 140° F. ; or, by Reaumur’s, the only difference in the process is to divide 
 by 4 instead of by 5. Thus, 60° R. X 9 ~ 4 -f- 32° = 167° F. 
 
STRONG BOILING. 
 
 5 
 
 Boiling of Liquids. — The heating and boiling of liquids is explain- 
 able by the principle of expansion. When heat is applied to a vessel 
 holding water, the particles of water nearest the fire become heated, and 
 consequently expand ; and in this expanded state, being lighter than the 
 particles above them, they rise to the surface and give place to another 
 layer of particles. These particles are in turn heated, and rise to the 
 surface ; and so on successively until the fluid is all heated to the point 
 at which it passes off as vapour or steam. The exact temperature at which 
 this takes place is stated above as 212 Q Fah,, but varies a little from the 
 amount of pressure upon its surface, so that water boils at a lower heat 
 upon a high hill than at the foot of it ; and for the same reason, it requires 
 a higher temperature to boil the water at the bottom of a deep pit than 
 upon the surface at the mouth of the pit— there being a greater pressure 
 of air at the bottom of the pit in proportion to the depth. 
 
 Substances Affecting Boiling Point. — Anything that gives an 
 increased attraction to the particles of a fluid also raises the temperature 
 of the boiling point. Some kinds of vessels — such as glass and polished 
 metals— retain the water with greater force than rough vessels, hence it 
 requires a little higher heat to boil water in vessels of polished material. 
 Water upon the surface of oil boils two degrees of heat below water in a 
 glass vessel, in consequence of the oil having no attraction for water. 
 
 Substances dissolved in water have often a similar effect, the attraction 
 of the two substances having to be overcome. Thus, alkaline leys — soda 
 or potash dissolved in water— require higher temperatures to boil them 
 than pure water does. But,, connected with this, we may mention a cir- 
 cumstance of great importance in the dye-house. In boiling alkaline leys, 
 so strong is the attraction of the water for the alkali, that it carries a small 
 quantity with it in passing off as steam; so that great care should be taken 
 in a dye-house where leys are being boiled, that the steam or vapour does 
 not come into contact with any colours that will be affected by alkalies. 
 Where convenient, it is, indeed, safest to have all alkaline leys boiled 
 entirely apart from where any coloured goods are likely to be exposed to 
 the influence of these vapours. We have seen many annoying and expen- 
 sive accidents caused by neglecting this precaution, especially upon such 
 colours as safflower reds and Prussian blues — these being often dried in a 
 shed by a current of air, the steam mixing with this hurts the colour. 
 
 Strong Boiling. — Another circumstance of common occurrence in 
 the dye-house is what is termed strong boiling. This means, that in the 
 process of boiling we increase the fire, in order to give the liquor more heat, 
 and make it hotter. We need hardly say that this is an error ; fora liquid 
 at the boiling point cannot be more heated by increase of fire, provided 
 it is not under pressure. All that is required is as much heat as will retain 
 it on the spring of the boil, and the liquid will then be as hot ns though it 
 boiled with the greatest violence. The only difference in strong boiling is, 
 
6 
 
 CHEMICAL EFFECTS OF HEAT UPON COLOURS. 
 
 that much more steam is driven off, which carries off the heat applied and 
 lessens the quantity of solution ; if a thermometer be placed in the liquor, 
 the temperature is found to be the same ; the only effect is that the extra 
 heat is rapidly carried off by the steam, causing a waste of fuel. The amount 
 of heat which steam thus takes away, is calculated, in round numbers, at 
 1000° Fah. per pound of water, which may be illustrated as follows : — If one 
 pound of water, at 32°, requires the burning of a pound of coal to bring it 
 to the boiling point (212°), the water will have received 180° of heat; if the 
 fire be continued at the same rate, it will take 5^- lbs. of coal to convert the 
 pound of boiling water into steam, and the temperature of the steam will 
 never be above 212° Fah. : thus 1000° of heat have been taken up by the 
 steam, and retained in what is termed a latent state — that is to say, in a 
 state not sensible to the thermometer. Or we may illustrate this principle 
 by another experiment: If we take 5^- lbs. of water at 32°, and pass a jet of 
 steam at 212° through it, until the water begins to boil, the whole water 
 will weigh 6^ lbs. ; thus 1 lb. of steam, has brought lbs. of water up 180°, 
 thereby shewing that this pound of steam had contained 1000° of heat. 
 These facts the practical dyer can easily apply to his own purposes. Steam 
 is very generally used in the dye-house as a heating agent for water, making 
 decoctions, and the boiling of goods. It is an observed fact that steam is 
 not so effective for many purposes as fire — as in the making of some decoc- 
 tions. The conditions noticed of the raising the boiling point of water 
 by the presence of matters held in solution, and by different kinds of 
 vessels, do not apply to liquids when boiled by steam. This may be the 
 cause of the observed difference of effect in the dye-house when making 
 decoction by fire and steam heat. Again, water boiled by passing a jet 
 of ordinary pressure steam into it, never gets above 210°, a small deficiency, 
 but sufficient to cause a difference in the results of many operations in 
 the workshop. This fact may be accounted for by the circumstance that 
 in boiling by steam there is no attraction of the water by the surface of 
 the vessel, as when boiled by fire, which, as has been observed by 
 Berzelius, causes the boiling point in different vessels to vary upwards of 
 2° ; hence 210° may be actually the true boiling point of water. For all 
 ordinary purposes steam, as a heating agent, is of the highest value to 
 the dyer. 
 
 Chemical Effects of Heat upon Colours. — The effects of heat in 
 relation to chemical combination and decomposition, are of the utmost 
 importance in all the operations of the dye-house. The influence of heat 
 in producing particular tints and colours, and also upon many colours when 
 produced, are subjects of every-day observation. Nevertheless, the conse- 
 quences are often so important that the subject cannot be too fully 
 impressed upon the minds of all interested. We shall, therefore, enumerate 
 a few of the more prominent effects in this place. 
 
 In making a decoction of quercitron bark for dyeing yellow, if it is 
 made at a temperature of about 90°, a much finer and purer yellow is 
 
CHEMICAL EFFECTS OF HEAT UPON COLOURS. 
 
 7 
 
 obtained than when the decoction is made by boiling, but the amount of 
 colour got at this temperature is not so great. When woollen cloth is dyed 
 by bark and then hotpressed, the heat impairs the colour ; but generally 
 dyed colours are more liable to be affected by heat when moisture is present 
 than in a dry atmosphere. For instance, a safflower red on cotton will 
 stand a high temperature when the air is dry, but if moisture be present, it 
 passes rapidly into a yellowish brown. If cotton dyed a Prussian blue be 
 placed in a moist atmosphere, and raised to the temperature of about 300° 
 Fah., it fades entirely in a few hours. A moist heat is hurtful to most 
 dyes. Many of the colouring matters of flowers, when imparted to cloth, 
 may be dried without change in the cold and dark, and afterwards be sub- 
 mitted to a temperature of 200° without alteration, but could not stand a 
 temperature of 95° without being altered, were these precautions not taken ; 
 such colours, therefore, if put on goods, could not be dried in a stove. 
 
 The kind of material on which the colour is dyed also influences the 
 effects of heat. Indigo blue dyed upon cotton is permanent, exposed to 
 heat and moisture ; but the same colour, with the same dye-stuff, upon silk, 
 is readily changed under those conditions. Safflower colours upon silk and 
 cotton, placed under similar circumstances in regard, to heat and moisture, 
 are affected differently ; that on the cotton is completely destroyed before 
 that upon the silk is at all affected. 
 
 Finding that heat affects colours differently when the heated atmo- 
 sphere is dry and when it is moist, it suggests the propriety of paying 
 strict attention to the condition of the drying-stove, and the hanging of 
 the coloured fabrics, so- as to give a free outlet to all moisture. If this is 
 neglected, the colours are subjected to a hot-vapour bath, and are under 
 the most favourable conditions to be destroyed by the joint action of the 
 heat and steam. 
 
 The same kind of colouring matter fixed upon cotton by different 
 mordants, is affected by heat differently, whether moisture be present or 
 not. This is very apparent with logwood colours, when fixed by tin or by 
 alumina. The different changes which these colours undergo in the pro- 
 cess of drying, and the dependence of these upon the state of the stove, 
 as to being hot and dry , or hot and moist , are familiar to the practical dyer. 
 But as we shall have occasion to- notice some of these changes when 
 describing the dye-stuffs, and the colours produced, we pass over the 
 details in this place. The following, however, may be stated as a general 
 rule — namely, that all organic colouring matters are destroyed at a heat 
 approaching to redness. There are some, however, such as indigo, which 
 sublime, or may be distilled by a heat less than sufficient to effect their 
 destruction. Those colouring matters which are volatile are in general 
 most permanent when fixed upon fabrics, and resist the action of heat best ; 
 and those colours that do not sublime are most susceptible of decomposition 
 under the combined influence of air, heat, and moisture. 
 
LIGHT. 
 
 Nature of Light. — The effects of light upon dyed colours are so closely 
 related to those of heat, and so powerful — particularly the direct rays of the 
 sun — that we cannot pass over the consideration of those phenomena, 
 which, however, we must understand as independent altogether of that 
 essential relation which light has to produce colour. Strictly speaking, 
 colours have no material existence, but are altogether the effect of light — 
 at least colours do not exist in the objects appearing coloured, but in the 
 light which is reflected from the apparently coloured object. In order, 
 then, to define colour, we may briefly state what is known upon the nature 
 and composition of light — at least so far as is necessary for our present 
 purpose. 
 
 There is believed to exist everywhere throughout all space, and sur- 
 rounding the atoms of all matter, an exceedingly thin and subtle ether called 
 the luminiferous ether. This is set into rapid vibration by all luminous 
 bodies, and these vibrations are propagated through the ether in waves 
 which strike the eye and produce the sensation of light. In this respect it 
 is similar to sound, which consists' of wave motions imparted to the air 
 by sonorous bodies. 
 
 If a ray or beam of white sunlight be allowed to pass through a hole 
 in a shutter into a dark room, and a glass prism be placed in its path, the 
 ray is found to be stretched out into a band of prismatic colours, ranging 
 from violet through Indigo blue, green, yellow, and finishing with red. 
 This band is called the spectrum ; and it is found that the varying colours 
 all through the band have separate wave lengths ; in fact, it is the wave 
 length in the vibratory motion of this ether that determines the colour of 
 the light, just as it is the wave length in sound determines the pitch. We 
 see, then, from the prism experiment, that white light is composed of all 
 the colours or waves vibrating together. When these waves composing a 
 ray of white light strike upon the surface of any substance, they may be 
 totally thrown back or reflected, in which case the substance will appear 
 white, or they may be almost totally absorbed or destroyed, in which case 
 the substance will have a black appearance. Again, they may find a free 
 passage through the substance, and when this is the case the substance is 
 said to be transparent ; indeed, when the transmission or passage of the 
 wave through a substance is perfect the substance is invisible. Now, 
 between these three extremes any number of combinations may occur, and 
 with every varying proportion of the number and nature of the waves 
 
RELATION OF COLOURS TO THE FABRIC. 
 
 9 
 
 reflected, absorbed, or transmitted, so will be the variety of colour and tint 
 and the amount of transparency or opacity. This subject, however, may 
 be very much simplified, as the spectrum is capable of being divided into 
 three broadly distinctive parts, the blue at the one end, the yellow in the 
 middle, and the red at the other end, as philosophers used to divide it, 
 distinguishing them as the three primary colours ; sometimes also termed 
 the chemical, the luminiferous, and the calorific rays or parts, owing to dis- 
 tinctive properties they possess. The blue is found most active in exciting 
 chemical action. The yellow has the greatest light-giving, and the red 
 the greatest heat-giving properties. We will hereafter speak of the 
 combinations of colours in this more popular sense, taking for our 
 illustrations these three primary colours — Blue, Yellow, and Bed. If the 
 different coloured rays are not reflected or absorbed in the same ratio, the 
 result is a colour according to the difference in the reflection or absorption 
 of the different ray or rays. If the red ray is absorbed, and only the blue 
 and yellow rays reflected, the object from which they are reflected appears 
 green ; if the yellow ray is also absorbed, the object appears blue ; or if 
 it is the blue ray that is absorbed, and red and yellow reflected, the 
 object appears orange; or if the yellow ray only is absorbed, the object 
 appears violet or purple. Thus, by the rate of the disturbing influence, and 
 the different combinations of these three colours, are all the various shades 
 in nature produced. The same substance may reflect some of the rays 
 and transmit others. Such a substance will have a different colour when 
 looked upon than when looked through. 
 
 Relation of Colours to the Fabric. — Although these remarks go 
 to prove that colour has no material existence in the body appearing 
 coloured, still the question is one of chemical and physical science. As 
 every change which a body undergoes affects the character of the substance 
 in its relations to light, the dyer’s object is, therefore, to effect a combina- 
 tion with his stuffs that will produce certain effects upon light, and thereby 
 produce colours. It is found, sometimes, that the nature of the fabric 
 affects the beauty and tint of a colour. A chemical compound may be ob- 
 tained that vies with nature, both in the beauty and brilliancy of its colour ; 
 but when that is obtained within the fibre of silk, cotton, or wool, the light 
 must be transmitted through the material as a medium, and the fibre not 
 being perfectly transparent the original beauty of the colour is much 
 diminished. Hence, the same colour, fixed within the fibres of those three 
 substances, has different appearances in each; the cotton never yields 
 the beauty of colour that the silk does, or even the wool. These circum- 
 stances, in all their relations, afford matter of constant study to the practical 
 dyer. 
 
 It may be said that we cannot follow nature in the production of colours 
 — that were the dyer to attempt to produce a white by an exact admixture 
 of blue, red, and yellow, he would fail, and would produce instead a black 
 or deep brown; but this would not be a proper application of the law 
 
10 
 
 EFFECTS OF DIFFERENT RAYS UPON COLOURS. 
 
 above stated. Nevertheless, to a certain extent, the practice of producing 
 white by the combining the three colours is had recourse to every day by the 
 practical bleacher and dyer. All goods coming from the bleaching process, 
 no matter what the nature of the process has been, have always a brownish 
 yellow tinge when compared with pure white: to cotton goods, a little 
 indigo or cobalt blue is added, and the result is a much purer white : to 
 silk, which has much more of the yellow tinge than cotton, a little Prussian 
 blue and cochineal pink, or what is more common, a little archil, which 
 gives a violet colour, is added, the quantity varying according to the depth 
 of yellow— the result is a much purer white. 
 
 The following simple experiment serves to illustrate how far the pro- 
 duction of colours depends upon the relation of the substance to light : — 
 Take a solution of iodide of potassium, which is colourless and transparent, 
 and divide it into three proportions: into the one pour a little acetate, of 
 lead (sugar of lead), into the other a persalt of mercury, and into the third 
 a little starch, with a few drops of nitric acid. These are all colourless 
 substances ; but after they are mixed, in the first we have a deep and 
 beautiful yellow ; in the second a red ; and in the third a blue. Thus we 
 have the three primitive colours produced by the same substance combining 
 with other substances, all previously colourless. If to a concentrated 
 solution of protosulphate of manganese, which is of a red colour, there be 
 added a solution of protochloride or protosulphate of iron, which are of a 
 green colour, there is produced a perfectly colourless solution. Many 
 white flowers, when macerated in water, yield a yellow colour, which 
 alkalies turn green and acids red. 
 
 Effects of Different Rays upon Colours. — The three separate rays 
 of light have peculiarities of action : one has heating power, and is there- 
 fore termed the calorific ray ; another has more of the property of giving 
 light, and is termed the luminous ray ; and the third has the greatest effect 
 in changing the composition of bodies, and is in consequence termed the 
 chemical ray. But in our remarks upon the effects produced by light, we 
 will speak of their total action. 
 
 The effects of heat upon dyed colours, which we have already de- 
 scribed, are equally applicable to light, the presence of moisture greatly 
 facilitating the effects. Reds, dyed by Brazilwood and a tin mordant, 
 exposed to light, pass into a brownish orange, and then gradually fade 
 away. Prussian blue becomes reddish, and passes into a dirty grey. 
 Yellows become brown, and then fade. The effects of light and moisture 
 are beautifully shewn by taking a piece of Prussian blue dry, and another 
 wet, and placing each under a glass, exposed to the rays of the sun for a 
 day. The wet piece becomes a reddish lavender, while the dry piece is 
 very little affected. Safflower colours are easily affected by light, but more 
 so when wet; so that when such colours are being dried in the air, care 
 should be taken to keep them from exposure to light. Even the most 
 permanent dyes, when exposed to sunlight, yield their colour. The follow- 
 
EFFECTS OF LIGHT CAUSING COMBINATION. 
 
 11 
 
 ing are the effects upon a few of the more ordinary colours, when exposed 
 to the sun for a few days, often in a few hours : — 
 
 Dark Indigo blues become light, with a greenish grey tint. 
 
 Analine blue loses its beauty and becomes light grey. 
 
 Yellow dyed by fustic becomes a straw colour. 
 
 Yellow dyed by chrome becomes greenish brown. 
 
 Red by madder, Turkey Red, becomes lighter. 
 
 Red by cochineal and spirits becomes paler. 
 
 Red by safflower becomes white, with a yellow tint. 
 
 Red by Magenta becomes very light. 
 
 Green with Indigo and chrome becomes light and dirty. 
 
 Green with vegetable yellow becomes dull and pale. 
 
 Black with logwood becomes brown. 
 
 When these colours are exposed wet, these effects are much sooner pro- 
 duced, so that it is not good to dry coloured goods by exposure to the sun. 
 
 The action of light upon different matters and colours, and its power 
 of changing the constitution of these substances, forms the subject of a 
 distinct branch of chemical study, known by the name of actino chemistry. 
 Mr. Robert Hunt says — “ The changes produced by the influence of the 
 solar rays are of a remarkable character, and few of them, in the present 
 state of our knowledge, can be satisfactorily explained. In some instances 
 it would appear that new properties are imparted to bodies by exposure to 
 sunshine ; in others, that radiation has the power of disturbing the known 
 chemical forces, and apparently establishing a new order of affinities ; whilst, 
 in all we are forced to recognise the operations of a principle, the nature 
 of which is involved in the most perplexing uncertainty.” The art of 
 photography is dependent on the action of light. 
 
 Effects of Light causing Combination. — We will here refer to a few 
 examples of the action of light upon substances, and the power it possesses 
 of inducing changes, with a view to impress upon the practical man the 
 necessity of a strict attention to all the conditions and circumstances in 
 which he may have to place his coloured fabrics and colouring materials. 
 In many cases bodies remain mixed and without action upon each other in 
 the dark, but combine rapidly and form new compounds when exposed to 
 light. Thus, chlorine and hydrogen may be kept mixed in the dark for 
 any length of time; but, if exposed to daylight, they silently combine and 
 form muriatic acid. If the mixture be exposed to strong sunshine, tho 
 combination becomes so rapid as to cause an explosion. 
 
 Chlorine, in water, remains a long time unaltered in the (lark, but by 
 exposure to light the water is decomposed, muriatic acid is formed, and 
 oxygen given off. These effects are observed daily in the operations of 
 bleaching. If grey goods are put into the bleaching liquor, and kept in 
 the dark, they whiten much more slowly than when exposed to light. 
 
12 
 
 LIGHT DECOMPOSES CHEMICAL COMPOUNDS. 
 
 Many bleachers know this, and expose their goods to light, and keep their 
 bleaching vessels in the lightest part of the premises. 
 
 Mixtures of chlorine with carbonic oxide, of chlorine with sulphurous 
 acid, and chlorine with pyroxilic spirit, and many other substances, are 
 similar examples of the same kind, being all inactive upon each other in the 
 dark, but combining easily and rapidly when exposed to light. 
 
 Light Decomposes Chemical Compounds. — Chemical compounds are 
 also decomposed by exposure to light. Carbonic acid gas exposed to 
 strong sunshine is decomposed into oxygen and carbon. This decomposi- 
 tion is supposed to go on daily in vegetable bodies during their growth, 
 causing them to give off oxygen and take up carbon. Colourless nitric 
 acid exposed to the sun soon becomes yellowish brown, from a portion of 
 it being decomposed, and the red nitrous fumes remaining in the acid, 
 produces the colour — which again shews the propriety of keeping the car- 
 boys with that acid in the shade as much as possible, as such changes by 
 the sun’s rays materially affect the preparation of many of the compounds, 
 which dyers have to make for themselves, and also the strength of the 
 acid. 
 
 Nitrate and chloride of silver — both white salts— become black by 
 exposure to light : paper or cloth saturated with these salts, and exposed 
 to light, is dyed permanently black. This is the principle of the art of 
 photography — an art now so well known as to require no special description 
 in this place. It has not yet been put to dyeing purposes, but concerning 
 which there is hope. A piece of paper prepared with a solution of silver, 
 and exposed to the coloured rays passing through a prism, as described 
 (page 8), is affected thus: — 
 
 Names of coloured ray. 
 
 Violet, 
 
 Indigo, 
 
 Blue, . 
 Green, 
 Yellow, 
 Orange, 
 
 Red, . 
 
 Change on paper prepared. 
 Purplish black. 
 
 Black not so purplish, 
 Black. 
 
 Green. 
 
 Red. 
 
 Faint brick red. 
 
 No change. 
 
 These results are exceedingly curious and interesting, and may point 
 out some useful application in respect to the preserving of compounds 
 from change, by keeping them in vessels which admit those rays only 
 which least affect them. 
 
 Solutions of substances are also affected by the sun’s rays, sometimes 
 sufficiently to cause a precipitation. A solution of proto -sulphate of iron 
 (copperas) in distilled water may be kept a long time clear in the dark ; 
 but, when exposed to sunshine, it becomes cloudy, and oxide of iron 
 precipitates. A solution of bichromate of potash, exposed to the sun’s 
 
PRACTICAL APPLICATION OF THE PRINCIPLES. 
 
 13 
 
 rays, acquires a property of precipitating many metals, as chromates, much 
 darker than will be produced by a similar solution kept in the dark. The 
 reddening and darkening of chrome colours by exposure to light is well 
 known to dyers. The effects of light upon precipitates are well known to 
 the manufacturers of lakes — which, let it be borne in mind, are simply the 
 colouring matter which constitutes the dyes, precipitated and dried — and 
 therefore the effect produced upon these precipitates is equally true of the 
 same colours as dyes. Sir H. Davy gives the following anecdote of a 
 maker of carmine — a lake made from cochineal : — 
 
 “A manufacturer of carmine, who was aware of the superiority of the 
 French colour, went to Lyons for the purpose of improving his process, 
 and bargained with the most celebrated manufacturer in that city for the 
 acquisition of his secret, for which he was to pay £1000. He was shewn 
 all the process, and saw a most beautiful colour produced, but he found 
 not the least difference in the French mode of fabrication and that which 
 had been constantly adopted by himself. He appealed to his instructor, 
 and insisted that he must have kept something concealed. The man 
 assured him he had not, and invited him to inspect the process a second 
 time. He minutely examined the water and the materials, which were in 
 every respect similar to his own; and then, very much surprised, said— 
 
 ‘ I have lost both my labour and my money, for the air of England does 
 not admit us to make good carmine.’ ‘ Stay,’ said the Frenchman, ‘ don’t 
 deceive yourself ; what kind of weather is it now?’ ‘A bright sunny day, 
 replied the Englishman. 1 And such are the days,’ said the Frenchman, 
 
 ‘ on which I make my colour ; were I to attempt to manufacture it on a 
 dark and cloudy day, my results would be the same, as yours. Let me 
 advise you, my friend, only to make your carmine on bright sunny days.’” 
 Probably in this case as much depended upon the knowing the instant for 
 arresting the action of heat upon the materials as upon the light. The 
 Frenchman having always prepared it under one circumstance, may have 
 been in error as to the cause. 
 
 Practical Application of the Principles. — In the application of some 
 of these phenomena to the trade, we must pause and inquire experimentally 
 how this can be effected. For instance, if we dissolve a piece of iron in 
 nitric acid, and expose a portion of this solution for some time to the rays 
 of the sun, and keep the other portion in the dark, on adding a solution of 
 prussiate of potash to each of these, the precipitate formed by the portion 
 exposed to light will be much deeper in colour than that kept in the dark. 
 Were we to reason directly from the result, we would expose our nitrate of 
 iron solutions to the light in order to have a deeper dye; but if we test this 
 by experiment, and dye a piece with each of the iron solutions, it will be 
 found that the darkest blue is obtained from the iron solution kept in the 
 dark. Thus, we observe, without experiment we may be liable to reason 
 falsely. The change effected upon the iron by the light may make it less 
 fit to enter within the pores or cells of the fibre ; or if the dye be a com- 
 
14 
 
 PRACTICAL APPLICATION OF THE PRINCIPLES. 
 
 bination of the stuff and fibre by affinity, these relations are affected — 
 which we will discuss more fully in another part of this work. 
 
 These brief notices of the more prominent effects of light upon colours, 
 and other compounds, will serve to impress the dyer with the importance of 
 attending to what he too often considers trifling circumstances ; and to 
 shew that while every different condition — the moisture of the air, the 
 temperature, the degree of light, &c. — are all acting and reacting upon the 
 substances composing his colours, both before and after they are fixed 
 upon the fabric, nothing should be considered too trifling or of too little 
 consequence to warrant its being overlooked. 
 
 The consideration of the chemical changes which are supposed to be 
 taking place in the vegetable kingdom through the influence of light, will 
 be more fully explained when we are treating of the colouring matters of 
 vegetables. 
 
 In connection with light, there is an application of a very important 
 practical kind which it will be well to notice — namely, the arrangement of 
 colours, so that their harmony should produce the best effect. Upon this 
 subject many propositions were made for the decoration and laying out 
 the manufactures in the Great Exhibition. Upon the philosophy of the 
 arrangement of different colours for effect, we will quote from the Athen- 
 aeum (. Athen ., 1851, page 273) a few passages upon this subject, which we 
 think will be useful to the dyer : — 
 
 “ The ‘successive 1 contrast has long been known ; and it consists in 
 the fact, that if you look steadfastly for a few minutes on a red surface 
 fixed on a white sheet of paper, and then carry your eye to another white 
 sheet, you will perceive on it not a red but a green one ; if a green, red ; 
 if purple, yellow ; if blue, orange. The ‘ simultaneous 1 contrast is the 
 most interesting and useful to be acquainted with. When two coloured 
 surfaces are in juxtaposition, they mutually influence each other — favour- 
 ably, if harmonising colours, or in a contrary manner if discordant ; and in 
 such proportion in either case as to be in exact ratio with the quantity of 
 complementary colour which is generated in our eye. For example, if two 
 half-sheets of plain tint-paper — one dark green, the other red — are placed 
 side by side on a grey piece of cloth, the colours will mutually improve, in 
 consequence of the green generated by the red surface adding itself to the 
 green of the juxtaposed surface — thus increasing its intensity — the green in 
 its turn augmenting the beauty of the red. This effect can easily be appre- 
 ciated if two other pieces of paper of the same colours are placed at a short 
 distance from their corresponding influenced ones, as below — 
 
 RED. RED GREEN. GREEN. 
 
 It is not sufficient to place complementary colours side by side to produce 
 harmony of colour, the respective intensities having a most decided 
 influence : thus pink and light green agree — red and dark green also ; but 
 light green and dark red, pink and dark green do not ; therefore, to obtain 
 the maximum of effect and perfect harmony, the following colours must be 
 
PRACTICAL APPLICATION OF THE PRINCIPLES. 
 
 15 
 
 placed side by side, taking into account their exact intensity of shade and 
 tint : — 
 
 HARMONISING COLOURS. 
 
 Primitive Colours. 
 
 Secondary Colours. 
 
 Red, 
 
 . Green, 
 
 Blue, 
 
 . Orange, 
 
 Yellow orange, 
 
 . Indigo, 
 
 Greenish yellow, 
 
 . Violet, 
 
 Black, 
 
 . White, 
 
 /■Light blue. 
 
 •^Yellow. 
 
 (Red. 
 
 /died. 
 
 3 Yellow. 
 
 (Blue. 
 
 (Blue. 
 
 3 Red. 
 
 (Yellow. 
 
 (Red. 
 
 3 Blue. 
 
 (Yellow. 
 
 (Yellow. 
 
 3 Blue. 
 
 (Red. 
 
 “If respect is not paid to the arrangement of colours according to 
 the above diagram, instead of colours mutually improving each other, they 
 will, on the contrary, lose in beauty : thus, if blue and purple are placed 
 side by side, the blue throwing its complementary colour, orange, upon the 
 purple, will give it a faded appearance ; and the blue receiving the orange- 
 yellow of the purple, will assume a greenish tinge. The same may be said 
 of yellow and red, if placed in juxtaposition. The red, by throwing its 
 complementary colour, green, on the yellow, communicates to it a greenish 
 tinge ; the yellow, by throwing its purple hue, imparts to the red a dis- 
 agreeable purple appearance. It is of very great importance that every one 
 should be acquainted with the laws of colours who intends to display or 
 arrange coloured goods or fabrics. 
 
 “The mixed contrast gives the reason why a brilliant colour should 
 never be looked at for any length of time, if its true tint or brilliancy is to 
 be appreciated; for if a person looks, for example, at a piece of red cloth 
 for a few minutes, green, its complementary colour, is generated in the 
 eye, and adding itself to a portion of the red, produces black, which 
 tarnishes the beauty of the red. This contrast explains why the shade of a 
 colour may be modified according to the colour which the eye has previ- 
 ously looked at, either favourably or otherwise. An example of the first 
 instance is noticed when the eye first looks to a yellow substance and then 
 to a purple one ; and as exemplifying the second case, looking at a blue and 
 then at a purple.” 
 
 Attention to these principles is of the first importance to the calico 
 printer ; for although the public may not understand why a certain arrange- 
 ment of tints please the eye, still there is a something about the proper 
 combination of colours that never fails to please. 
 
ELEMENTS OF MATTER. 
 
 Differences between an Element and Compound. — It has been intimated 
 that the conditions of matter— solidity, fluidity, and gasuity — depend upon 
 heat ; and it was also stated that in each state there is a vast variety — a 
 variety so great that the idea of telling where any one variety begins and 
 ends is a task seemingly beyond human power. Nevertheless, by labour, 
 by experiment, and comparison, much has been done not only to distin- 
 guish every variety of substance, but why one substance differs from 
 another both in appearance and quality. Let us take a known compound 
 as an illustration :■ — When a piece of steel is placed in diluted sulphuric 
 acid, the acid dissolves the greater part of it ; but there is left undissolved 
 a black matter, which, by testing, we find to be charcoal or carbon, and 
 that which has been dissolved is iron. We therefore infer that steel is 
 composed of iron and charcoal— that it is a compound substance ; but if we 
 take the carbon, and treat it in any way within our power, we find it still 
 the same, without components. In the same manner let us test iron — 
 dissolve it, melt it, or treat it as we will, it yields nothing but iron. All 
 such substances, then, that resist every effort to decompose, or shew any 
 admixture, are termed elementary, or simple substances. The number of 
 such elements known to the chemist at the present time are sixty-three ; 
 and all the varieties in which we find matter presenting itself to us — 
 whether in the mineral, the vegetable, or the animal kingdoms — are made 
 up of one, or a mixture of two or more of those sixty-three elements. 
 The following table gives the names and particulars necessary to be 
 observed in the study of these elements : — 
 
 Aluminum .. 
 
 Symbol. 
 
 A1 
 
 
 Equivalent. 
 
 27-26 
 
 Cobalt 
 
 Symbol. 
 
 ....Co = 
 
 Equivalent. 
 
 58-74 
 
 Antimony ... 
 
 Sb 
 
 
 122-3 
 
 Copper 
 
 ....Cu — 
 
 63-12 
 
 Arsenic 
 
 
 = 
 
 75-15 
 
 Didymium ... 
 
 ....D = 
 
 94-96 
 
 Barium 
 
 .....Ba 
 
 = 
 
 137-14 
 
 Erbium 
 
 ,...E == 
 
 112-6 
 
 Bismuth 
 
 Bi 
 
 
 210-0 
 
 Fluorine .... 
 
 ....F — 
 
 18-96 
 
 Boron 
 
 Bo 
 
 = 
 
 11-04 
 
 Glucinum ... 
 
 ....Gl — 
 
 9-30 
 
 Bromine 
 
 .....Br 
 
 r — i ' 
 
 79-95 
 
 Gold 
 
 ...Au = 
 
 196-71 
 
 Cadmium.... 
 
 Cd 
 
 ;= 
 
 112-04 
 
 Hydrogen ... 
 
 ,...H — 
 
 1-0 
 
 Caesium 
 
 Cs 
 
 
 133-00 
 
 Indium 
 
 In = 
 
 113-4 
 
 Calcium 
 
 Ca 
 
 = 
 
 40-00 
 
 Iodine 
 
 ....I m 
 
 126-85 
 
 Carbon 
 
 C 
 
 == 
 
 12-00 
 
 Iridium 
 
 ...Jr — 
 
 196-87 
 
 Cerium ...... 
 
 Ce 
 
 — 
 
 92-16 
 
 Iron 
 
 ....Fe — 
 
 56-00 
 
 Chlorine ... 
 
 Cl 
 
 — 
 
 35-46 
 
 Lanthanium , 
 
 .....La — 
 
 92-88 
 
 Chromium . . 
 
 ....Cr 
 
 — 
 
 52-08 
 
 Lead 
 
 ....Pb — 
 
 206-92 
 
DIFFERENCES BETWEEN AN ELEMENT AND COMPOUND. 
 
 17 
 
 Lithium 
 
 Symbol. 
 
 ...Li 
 
 
 
 Equivalent. 
 
 7-02 
 
 Silver 
 
 Symbol. 
 
 Ag 
 
 — 
 
 Equivalent. 
 
 107-93 
 
 Magnesium . 
 
 -Mg 
 
 = 
 
 24-0 
 
 Silicon 
 
 
 = 
 
 28-10 
 
 Manganese ... 
 
 ...Mn 
 
 = 
 
 54-04 
 
 Sodium 
 
 Na 
 
 = 
 
 23-04 
 
 Mercury 
 
 ...Hg 
 
 = 
 
 200-00 
 
 Strontium . 
 
 Sr 
 
 = 
 
 87-54 
 
 Molybdenum 
 
 ...Mo 
 
 = 
 
 96-00 
 
 Sulphur .... 
 
 ...... S 
 
 = 
 
 32-07 
 
 Nickel 
 
 ...Ni 
 
 .= 
 
 58-74 
 
 Tantalum .. 
 
 Ta 
 
 = 
 
 182-30 
 
 Niobium 
 
 „..Nb 
 
 = 
 
 04-0 
 
 Tellurium . 
 
 Te 
 
 = 
 
 128-06 
 
 Nitrogen 
 
 ...N 
 
 = 
 
 14-0 
 
 Thalium .... 
 
 ,T1 
 
 = 
 
 203-64 
 
 Osmium 
 
 
 = 
 
 199-0$ 
 
 Thorium ... 
 
 Th 
 
 = 
 
 115-72 
 
 Oxygen 
 
 ....0 
 
 — : 
 
 16-00 
 
 Tin 
 
 
 = 
 
 118T0 
 
 Palladium.... 
 
 ...Pd 
 
 = 
 
 106-57 
 
 Titanium . . 
 
 Ti 
 
 = 
 
 50-00 
 
 Phosphorus.. 
 
 ....P 
 
 = 
 
 31-00 
 
 Tungsten . . , 
 
 W 
 
 = 
 
 184-00 
 
 Platinum...... 
 
 ...Pt 
 
 = 
 
 197-18 
 
 Uranium.... 
 
 U 
 
 = 
 
 120-00 
 
 Potassium .... 
 
 ,...K 
 
 — 
 
 39-13 
 
 Vanadium . 
 
 V 
 
 = 
 
 51-35 
 
 Rhodium 
 
 ...Rh 
 
 = 
 
 104-21 
 
 Yttrium .... 
 
 Y 
 
 = 
 
 61-70 
 
 Rubidium.... 
 
 ...Rb 
 
 — 
 
 85-40 
 
 Zinc 
 
 Zn 
 
 = 
 
 65-16 
 
 Ruthenium .. 
 
 
 — 
 
 104-40 
 
 Zirconium . 
 
 Zr 
 
 = 
 
 89-60 
 
 Selenium 
 
 ....Se 
 
 — 
 
 79-46 
 
 
 
 
 
 "When two or more of these elements combine together, it is found 
 that the union does not take place indeterminately, but always in definite 
 proportions. ’ Those proportions are expressed by the figures placed 
 opposite to the names in the above table. For example, if we mix 
 together one ounce of hydrogen and one ounce of oxygen, and bring 
 them under circumstances to cause combination, it is found that the one 
 ounce of oxygen has combined with an eighth part of the hydrogen, or 
 two drams, and that other seven ounces of oxygen are required to combine 
 with the whole of the hydrogen. Their combining properties are there- 
 fore set down as 1 to 8. The same law holds good for every other element; 
 so that the union is invariably distinct and definite. This has relation to 
 the actual and relative weight with which two elements combine. Hydro- 
 gen being the lightest of the elements, one volume of it was taken as the 
 standard, with which all the others were compared; but experiment shewed 
 that by this method many of the elements, such, for example, as oxygen, 
 would occasionally have a combining proportion of only half a volume, 
 and as volume is equivalent to atom, there cannot be half an atom. 
 This difficulty has been got over by fixing upon one volume of oxygen as 
 the standard, which consequently is called 16 as the equivalent weight, 
 so that instead of water being formulated as 110 = 9, it is now represented 
 as Ii 2 0 = 18, thus the same relation is retained. This will explain the 
 difference of the combining numbers affixed to the elements in the table 
 compared with those in our former edition ; several remain as before, many 
 are doubled, and some are tripled — each number refers to the weight of one 
 volume of the element. In reference to the combining of volumes, there 
 is much to interest the philosophic mind, which we will briefly indicate, in 
 
18 
 
 DIFFERENCES BETWEEN AN ELEMENT AND COMPOUND. 
 
 hopes of sending the reader to works devoted to the subject of chemical 
 philosophy.. If we take one cubic inch of hydrogen and one cubic inch of 
 chlorine, they combine and form two cubic inches of hydrochloric acid. 
 If we take one cubic inch of oxygen and two cubic inches of hydrogen, 
 they combine and form water, and make only two cubic inches ; the first 
 of these results is 'termed Monad, the second is termed Diad combina- 
 tions. One cubic inch of nitrogen combines with three cubic inches of 
 hydrogen, forming ammonia, and making only two cubic inches. The 
 following compounds will probably be more familiar to the dyer, and serve 
 to illustrate : — 
 
 Nitric oxide, 
 
 N 
 
 |o|. 
 
 
 
 
 
 Nitrous oxide, 
 
 N 
 
 N 
 
 0 
 
 
 
 
 Hyponitric acid,... 
 
 M 
 
 1° 
 
 1 0 
 
 
 
 
 Nitrous acid, 
 
 N 
 
 01 
 
 01 
 
 |0| 
 
 0 
 
 
 Nitric anhydrate,.. 
 
 0 
 
 0 
 
 0 
 
 0 
 
 0 
 
 0 
 
 0 
 
 NO equivalent 30 
 44 
 
 NoO 
 
 NO< 
 
 N,0, 
 
 n 2 o 5 
 
 46 
 
 76 
 
 108 
 
 The reader will observe here that the addition of oxygen in most cases 
 adds nothing to the bulk, but increases the weight of the compound. How- 
 ever, as we look upon these results, we cannot refrain from the thought that 
 there is something more simple to be yet found. From the above it is 
 seen that one element is often found to combine with another in a great 
 number of proportions. Thus, nitrogen — which, according to the table, 
 has a combining equivalent or weight of 14 — combines with oxygen in 
 proportions as under: — 
 
 Two nitrogen = 28 to one oxygen = 16. 
 
 One nitrogen = 14 to one oxygen = 16. 
 
 Two nitrogen = 28 to three oxygen = 48. 
 
 Two nitrogen = 28 to four oxygen — 64. 
 
 Two nitrogen = 28 to five oxygen = 80. 
 
 Thus we observe that the proportion of oxygen is always 16, or a multiple 
 of 16 ; so it is with nitrogen, always 14, or twice 14, and so on to any 
 number of multiples of 14 or 16. The same rule holds good with every 
 element in the table ; they combine only according to the number follow- 
 ing the name. 
 
 But when they thus combine in different and distinct quantities, the 
 compounds formed are also distinct and definite. Thus, two proportions 
 of nitrogen and one oxygen is laughing gas; and it is so at all times and 
 under all circumstances, and can be nothing else. But when two of 
 
USE OF SYMBOLS. 
 
 19 
 
 oxygen combine with one of nitrogen, a different substance is formed from 
 laughing gas, also distinct and definite from every other proportion in 
 which the elements unite. The first and last of the above list form an apt 
 illustration — - the former being laughing gas, the latter pentoxide of 
 nitrogen, formerly hypothetical nitric acid (aquafortis). 
 
 Use of Symbols. — The letters placed immediately after the names of 
 the elements in the above table are the symbols commonly used to 
 represent the respective elements, and facilitate the expression of the 
 compounds into which they enter. Thus, to represent laughing gas, we 
 write N 2 0, which means two of nitrogen and one of oxygen. The symbol 
 always represents the volume, the weight of which is given in the table, and 
 the figures attached shew how often that proportion or volume is repeated. 
 Thus, the formula for pentoxide of nitrogen, N 2 0 5 , which means two 
 parts of nitrogen and five of oxygen — the figure being placed immediately 
 after the symbol which is to be multiplied ; but sometimes there may be 
 two or more proportions of a compound combined with another com- 
 pound: this is represented by placing a large figure before the compound 
 to be multiplied, and a comma at the end. For example, two proportions 
 of pentoxide of nitrogen united with one of water should be expressed 
 thus, 2 N 2 O 5 , H 2 0. The figure 2 preceding applies to all between it and the 
 comma. Some use the sign -j- instead of a comma — thus, 2N 2 0s II 2 0. 
 
 It being important to the student .that these be fully understood before 
 beginning to read for study, we will take another series of compounds : — 
 
 H 2 SO 2 hypo-sulphurous acid; two hydrogen, one sulphur, and two oxygen. 
 
 50 2 anhydrous sulphurous acid ; one sulphur and two oxygen. 
 
 H 2 S0 3 sulphurous acid ; two hydrogen, one sulphur, and three oxygen. 
 
 50 3 anhydrous sulphuric acid ; one sulphur and three oxygen. 
 
 H 2 S0 4 sulphuric acid ; two hydrogen, one sulphur, and four oxygen. 
 H 2 S0 4 +H 2 0 sulphuric acid, with one equivalent of water. 
 
 HaS0 4 -|-2H 2 0 sulphuric acid, with two equivalents of water, being acid 
 
 at about 120°. — Twaddell. 
 
 To make up the equivalent weight of any compound from symbols, 
 wo have simply to multiply the elements given according to the table. 
 Thus, suppose we take the sulphuric acid and two water, we have — 
 
 Two hydrogen, 1 = 2 
 
 One sulphur, equivalent weight, 32 = 32 
 
 Four oxygen, 16x4 = 48 
 
 Two water, ....: 2 Hy. and 16 oxygn..... = 18 x 2 = 36 
 
 I* 118 
 
 which is the proportion or weight of sulphuric acid of the strength which 
 would be required to combine with any element, suppose iron, which 
 
20 
 
 RULES FOR NAMING COMPOUNDS. 
 
 is 56; therefore it would require fully twice the weight of sulphuric acid 
 of this strength to that of a piece of iron to dissolve it. 
 
 Nomenclature. — In the nomenclature of these elements in the above 
 table there has been no definite rule followed. They have been named 
 either from the fancy of the discoverer or from some leading property or 
 appearance they presented, which appearances will be noticed under their 
 separate descriptions; but, in naming compounds, a distinct rule has 
 been adopted, so that the name of the compound expresses, as nearly as 
 possible, its composition and property. We will give a few of the leading 
 principles observed in this rule of naming compounds. 
 
 Kules for Naming Compounds. — When two elements combine to- 
 gether, and the compound formed has not acid properties, the name ends 
 in ide, such as oxide , chloride , bromide , iodide , &c. Formerly uret was used 
 instead of ide , such as in sulphur et, carburet , phosphuret , &c. ; but ide is now 
 generally adopted for these, giving sulphides , carbonides , phosphides , &c. 
 When the compound formed by the union of the elements has acid 
 properties, the name ends in ic or ous; thus we have sulphuric , sulphurous , 
 nitric , nitrous , chloric , and chlorous acids. Elements, uniting together in 
 different multiples, have prefixes added to express the number of propor- 
 tions. Thus, pro to denotes one proportion, or first; bi, two proportions; 
 tri, three proportions ; per denotes no particular number, only the highest 
 proportion. As examples, take the compounds of hydrogen and nitrogen, 
 already noticed : — 
 
 NO protoxide of nitrogen. 
 
 N0 2 binoxide of nitrogen. 
 
 N0 3 trioxide. 
 
 N0 4 tetroxide. 
 
 NO 5 pentoxide. 
 
 Thus, we observe, the full name of the substance not having acid pro- 
 perties denotes its composition. In the case of acids, it does not tell the 
 number of elements combined, as with oxides — ous simply signifying that 
 it has less oxygen than another acid composed of the same elements, and 
 which ends in ic. There are sometimes more than two acids formed by 
 the combining of the same elements; in this case, if the oxygen is less 
 than in the acid whose name terminates with ous, the prefix hypo is put to 
 the name of the ous acid ; if there be more oxygen than in the ous acid, 
 and less than the ic acid, the same prefix is made to the last-named acid. 
 Finally, when there is more oxygen present than in the acid whose name 
 terminates with ic, the prefix per is put, as in oxides. The following 
 illustrations will exemplify these terms : — 
 
 H 2 S0 2 hypo^sulphurous acid. 
 
 H 2 S0 3 sulphurous acid. 
 
 H 2 S 2 0 3 hypo -sulphuric acid. 
 
 H 2 S (>4 sulphuric acid. 
 
SALTS-— THEIR NATURE AND NOMENCLATURE. 21 
 
 Any acid found having more oxygen, in relation to the sulphur, than the 
 last named in this list, would be called per- or di- or in-sulphuric acid, 
 per being highest. It will thus be seen that the names of the compounds 
 denote their composition, and give an idea of their leading properties. 
 The term sesqui — as sesquioxide — - which was often used, meant one 
 and half of an equivalent, which, from what has been said, cannot take 
 place. Nevertheless, the name is conveniently retained to denote such 
 compounds as have two of one element and three of another; such as 
 sesquioxide of iron, also termed peroxide, and which is composed of 
 two iron with three oxygen, FegOs. Sometimes one proportion of oxygen, 
 chlorine, &c., combines with two proportions of a base as a metal; 
 such compounds have the prefix sub, or di, as — 
 
 Fe 2 0, sub-oxide of iron, or dinoxide of iron. 
 
 Cu 2 Cl, sub -chloride, or dichloride of copper. 
 
 When one proportion of oxygen, chlorine, &c., combines with three of a 
 metal, the prefix trisub or tridi, is occasionally used; but this is not very 
 convenient; the best and most general plan is to denote such compounds 
 as basic, and then apply the ordinary prefixes, such as bibasic, tribasic, &c., 
 thus : — 
 
 CU 2 O, bibasic oxide of copper. 
 
 Cu 3 0, tribasic oxide of copper. 
 
 In the name of a compound ending in ide, the base or element with 
 which the oxygen, chlorine, &c., is combined, used to be given last, as 
 
 Oxide of iron. Oxygen and iron. 
 
 Chloride of iron. Chlorine and iron. 
 
 Now it is reversed, as 
 
 Ferrous oxide. Ferrous chloride. 
 
 With compounds having acid properties, the base is placed at the begin- 
 ning, thus: — 
 
 Sulphuric acid. Sulphur and oxygen. 
 
 Nitric acid. Nitrogen and oxygen. 
 
 Hydrochloric acid. Hydrogen and chlorine. 
 
 Salts — Their Nature and Nomenclature. — The acids combine with 
 other substances, such as the metals, and form another class of compounds 
 termed Salts. The names of these also denote their composition : the salt 
 formed with the acid terminating in ic and a base, ends with ate; that 
 formed by the acid terminating in ous ends with ite, the name of the 
 element with which the acid combines being added. Thus, 
 
 Sulphuric acid and iron form sulphate of iron. 
 
 Sulphurous acid and iron ... sulphite of iron. 
 
22 
 
 SALTS — THEIR NATURE AND NOMENCLATURE. 
 
 Some have altered these terms into sulphic acid and sulphous acid, hence 
 the above is snlphic iron and sulphous iron. When these acids unite with 
 elements or bases in different proportions, the same prefixes are used as 
 with oxides. If one proportion of acid unites with one of another element, 
 the compound is termed proto, as proto -sulphate of iron; if two of acid 
 and one metal, the compound has hi, as bisulphate of iron, &c. Per is 
 also used as denoting the highest proportion — as, when three equivalents 
 of acid unite with two equivalents of iron, the salt is termed persulphate 
 of iron. 
 
 Sometimes we have the metal uniting with acids, forming basic salts, 
 as described in the case of basic oxides; such as having two proportions of 
 metal to one of acid, and three proportions or equivalents of metal to one 
 of acid. In such cases, the same prefixes are used as we have before 
 stated — namely, hibasic sulphate of copper, two equivalents of copper to 
 one of sulphuric acid; trihasic sulphate of copper, three copper to one 
 acid. 
 
 Combinations of water with oxides or salts are termed hydrates , or the 
 compound is termed hydrous , in contradistinction to substances having no 
 water, which are termed anhydrous — thus, hydrate of potash, or hydrous 
 potash, K 2 0H 2 0; anhydrous potash, K 2 0. 
 
 These formulae may appear at first sight rather puzzling, and require 
 a little explanation in addition to our remarks at page 20. In the old way 
 of stating these compounds we had — 
 
 Anhydrous potash, KO = 47 
 Hydrous potash, KOHO= 56 
 
 Although the equivalent of oxygen is doubled, the potassium equivalent 
 remains as formerly, so that 
 
 Anhydrous potash is now K 2 0 = 94 
 Hydrous potash is now K 2 0H 2 0 = 112 
 
 In this last there are two hydrogen, two potassium, and two oxygen, which 
 would be formulated H 2 K 2 0 2 ; instead of this it is divided HKO = 56. 
 
 The reader will meet with several compounds and hydrates formulated 
 in the same manner. 
 
 Two salts sometimes unite together, and form a definite compound, 
 which is termed a double salt. Alum is a good instance of this class of 
 compounds: it is a double salt of sulphate of alumina and sulphate of 
 potash. 
 
CHEMICAL AFFINITY. 
 
 The elements of matter have a disposition, if we may use the term, to unite 
 with one another : this disposition is termed affinity , or chemical attraction. 
 The affinity of any one element for the others is not equal, but is greater 
 for some one element, or for a particular class of elements. Thus, oxygen 
 has a stronger attraction under ordinary circumstances for those elements 
 the combining with which forms alkalies, than for any of the others ; and 
 amongst these potassium has the strongest affinity for oxygen, so that, by 
 the operation of this law, should a number of elements be arranged to- 
 gether, under proper circumstances for combining, those which have the 
 strongest attraction for each other will combine first. The same law holds 
 good when compound bodies unite together. Were we to take sulphuric 
 acid, and add to it a mixture of potash and magnesia, the acid would com- 
 bine with the potash with greater force than it would with the magnesia ; 
 and were there not enough of acid to combine with the whole of the 
 mixture, a part of the magnesia would be left, because the potash has a 
 stronger attraction for this acid than magnesia. This peculiarity of select- 
 ing is not merely owing to the substance having acid properties, but from 
 a stronger attraction existing between the base and acid compounds. 
 Thus the two acids, sulphuric and muriatic , comport themselves towards 
 the following bases, as under : — 
 
 Muriatic Acid. 
 Silver. 
 Potash. 
 
 Soda. 
 
 Barytes. 
 
 Strontia. 
 
 Lime. 
 
 Magnesia. 
 
 Sulphuric Acid. 
 Barytes. 
 Strontia. 
 Potash. 
 
 Soda. 
 
 Lime. 
 
 Magnesia. 
 
 Silver. 
 
 Although we have named silver here under the sulphuric acid column, 
 in order to complete the comparison, it is not immediately next to mag- 
 nesia in affinity for that acid ; a great many of the other metals rank before 
 it, such as mercury, copper, iron, zinc. So that were any of these metals 
 added to a solution of sulphate of silver, the acid would leave the silver 
 and combine with it — the silver being precipitated. 
 
 It is this law of affinity that regulates compositions and decomposi- 
 tions, all of which are matters of daily experience in the dye-house . 
 particularly that class of decompositions termed double, in which two 
 salts being put together, there takes place a mutual exchange of partners, 
 
24 
 
 CATALYTIC INFLUENCE. 
 
 if we may so term it. For instance, in mixing nitrate of iron with yellow 
 prussiate of potash, the nitric acid leaves the iron and combines with the 
 potash, while the iron and prussic acid combine, forming Prussian blue. 
 When any of the two compounds so combined forms an insoluble sub- 
 stance, the decomposition is always more apparent, more complete, and 
 most applicable to dyeing purposes. Compounds which cannot easily be 
 formed directly by bringing their elements together, are often formed 
 by means of double decomposition : thus, carbonate of iron is difficult to 
 form directly, but by mixing a solution of carbonate of soda with sulphate 
 of iron, this compound is instantly formed, which may be thus represented — 
 
 NaCQ* FeS0 4 = FeC0 3 NaS0 4 
 
 Application of Affinity. — These double decompositions and recom- 
 positions are of the utmost importance to the practical dyer, who should 
 make himself thoroughly acquainted with all their laws and conditions ; as 
 it is these formations of new and often insoluble compounds which con- 
 stitute a prominent feature in the production of colours, and every circum- 
 stance connected with this class of phenomena favours this kind of reaction 
 for practical purposes. It is a general law that in the rapid union of two 
 elements, or of a compound with an element, such as dissolving a metal in 
 acid, that there is always a great evolution of sensible heat. This circum- 
 stance would interfere with many dyeing operations, affecting both the fibre 
 and colour ; but in the double affinity referred to, where two compounds 
 merely exchange elements, there is no sensible heat evolved to interfere 
 with the dyeing operations or fabric. The interchange of elements takes 
 place quietly, so that the dyer may fix within the fibres of the most 
 delicate material any compound required for the colour. 
 
 Circumstances Influencing Affinity. — The force of affinity is greatly 
 influenced by the conditions in which the combining bodies are placed, as 
 indicated when treating of light and heat. Solid bodies, in general, have no 
 chemical action upon one another ; therefore, before any chemical change 
 can take place, it is necessary to bring the substance into a fluid state. 
 This is eminently necessary in all dyeing operations, not only for the 
 purpose of causing combination, but to enable the particles to enter within 
 the fibres of the cloth, and to be, while there, acted upon by the affinity 
 of another body, also in solution, brought into contact with them. This 
 is an essential condition of all dye drugs, and of all salts used in dyeing, 
 either as dyes or mordants, and must never be lost sight of in studying 
 either its philosophy or practical application, as anything that interferes 
 with the free operation of these conditions necessarily retards the process 
 or deteriorates the dye. 
 
 Catalytic Influence. — Another circumstance or power sometimes 
 occurring in dyeing operations, which interferes with or directs chemical 
 affinity amongst the particles of bodies is, that one body often induces a 
 
CONSTITUTION OF SALTS. 
 
 25 
 
 chemical change in another, while it undergoes no change itself. This 
 kind of affinity or power is termed Catalysis. A good instance of this is 
 in fermentation: a little yeast put into beer induces fermentation in all 
 the solution, while the yeast is not altered. If we boil starch with dilute 
 sulphuric acid, the starch is first changed into gum and then into sugar. 
 Yet, notwithstanding these changes, the sulphuric acid is found unaltered, 
 either in property or quantity. A great many substances possess this 
 property of catalytic influence ; and it is not unlikely that fibrous materials, 
 such as silk, woollen, and cotton, possess it towards many of the vegetable 
 colouring matters used in dyeing ; indeed, many operations in the dye- 
 house indicate the presence of some such influence. The real nature of 
 this power is not well understood ; only we know that bodies subject to 
 change by catalysis have their particles held together by a weak affinity, 
 and therefore changes are less or more easily effected, according to the 
 power exerted, to keep their elements together. The elements of many 
 organic compounds seem held together by a mere balance of power among 
 them, so that while another substance put into such a compound may 
 possess a sufficient attraction for some of the elements in the compound to 
 disturb this balance of power, yet it may not have sufficient power to com- 
 bine with them, but only cause the whole elements to re-arrange them- 
 selves in a new and probably more stable form. The study of such re- 
 actions is of the greatest interest; and as these principles of action, in all 
 probability, play a prominent part in the art of dyeing, it will be again 
 brought under consideration when describing operations where we think 
 this action takes place. We may here mention, however, that the intro- 
 duction of such a term as catalysis is only considered useful as bringing 
 under one group a certain class of phenomena ; but, indeed, the same may 
 be said of the no less useful term affinity. When our knowledge of these 
 hidden powers is more extended, all those phenomena may, perhaps, be 
 accounted for, and ranged under the operation of some one universal 
 power or law, of which at present we know only by particular terms : 
 until then the names are useful. 
 
 Constitution of Salts. — It may have been observed that, in describ- 
 ing the constitution of compounds and their nomenclature, the elements 
 are grouped together in a certain order, not only shewing their composition 
 in so far as the elements and the number of equivalents are concerned, but 
 how these elements are arranged in the compound salt. Salts were long 
 considered to be a double compound of an acid with the oxide of a metal. 
 Thus, sulphate of iron was represented as FeOSO a , being sulphuric acid 
 combined with oxide of iron, the name being the sulphate of the protoxide 
 of iron ; but the results of an extensive series of investigations by different 
 chemists have altered these views, and different formula) have been pro- 
 posed, not affecting the actual composition of the salts, but the supposed 
 manner in which the elements group themselves together in the compound. 
 However, it is not intended to enter here into the merits of the different 
 
26 
 
 CONSTITUTION OF SALTS. 
 
 views which, have been entertained by chemists regarding this point, but 
 briefly to give a general idea as a guide to the workman. We will take 
 sulphuric acid as our first illustration. The composition of this acid was 
 given as S0 3 , but S0 3 is a solid crystalline compound, which has no acid 
 properties until it is combined with one proportion of water, being then 
 SO 3 -f- HO, or hydrous sulphuric acid. If into this acid we place a piece 
 of iron, the reaction was expressed thus, SO s HO -J- Fe — SO s FeO -f- H ; 
 or as follows : — 
 
 Water, 
 
 jo ..„ 
 
 * Ih x 
 
 Hydr nnrp n gas 
 
 Sulphuric acid,.... 
 Iron 
 
 S0 3 
 
 ....Fe.. 
 
 Xs, Protosulphate of iron. 
 
 Here we have water decomposed, to give an atom of oxygen to the iron 
 forming an oxide ; and then we have the acid combining with this oxide. 
 The same principle of action is ascribed to all metals, and used to be 
 described as a sort of disposing affinity. The acid S0 3 is conceived to 
 have such an attraction for the oxide of the metal, that it disposes both 
 the metal to combine with oxygen and the oxygen with the metal, in order 
 that it might unite with the two to form a salt. Sir H. Davy, with his 
 usual clear perception of all chemical phenomena, thought that as sulphuric 
 acid SO 3 had no acid properties, and was incapable of combining with 
 any body as such, except in union with water, it was more probable that 
 what is termed hydrated sulphuric acid S0 3 -j- HO, may be the true com- 
 position of sulphuric acid, rather than S0 3 , and therefore ought to be 
 represented thus, S0 4 + H— the hydrogen being the base or metal, and 
 that its presence is an essential qualification to the acid, so that a piece of 
 iron being put into sulphuric acid will have a reaction as under, S0 4 H -}- 
 Fe = S0 4 Fe -}- H : — 
 
 Sulphuric acid, 
 Iron, 
 
 .... 
 
 (S0 4 
 Fe... 
 
 .Hydrogen gas. 
 ■Sulphate of iron. 
 
 Here we have no supposed primary- disposing action, but the iron 
 simply taking the place of hydrogen, by substitution, in virtue of S0 4 , 
 having a stronger affinity for it than for the hydrogen. The same reaction 
 explains the dissolving of any other metal in sulphuric acid. Names were 
 proposed in accordance with this theory, as, for instance, the S0 4 was 
 termed sulphion; therefore, S0 4 -f- II, instead of being termed sulphuric 
 acid, would be sulphionide of hydrogen, and sulphate of iron, sulphionide 
 of iron; now they are hydric sulphate and ferrous sulphate. Such new 
 names, however, are very difficult to introduce ; and although they may 
 be used and approved of by chemists, their use in the arts must necessarily 
 be a matter of gradual growth. 
 
 The views given above, of the true formula of sulphuric acid, may be 
 
SALT KADICALS. 
 
 27 
 
 applied to all hydrated acids. The so-called nitric anhydride of the 
 formula N 2 Q 5 not an ac ^- There is N 2 0 5 -f-H 2 0, hydrated nitric 
 acid; but why N 2 0 5 -f- H 2 0, rather than N 2 0 6 -f- H 2 ? from doubling the 
 equivalent of oxygen, nitric acid is represented as HN0 3 , instead of 
 N 2 0 6 H 2 . Metals dissolving in it only replace the hydrogen. The same 
 with muriatic acid, which is a compound of hydrogen and chlorine, pro- 
 perly termed hydrochloric acid. In dissolving a metal in this acid, the 
 acid, not the water, is decomposed. Or if we put hydrochloric acid upon 
 the oxide of a metal, say soda, the action is not that of the acid combining 
 with the oxide, but there is a double decomposition and composition re- 
 presented by HC1, NaHO =NaCl, H 2 0. So that bodies termed muriates 
 are more properly chlorides. 
 
 Salt Radicals. — There is another thing necessary for the student to 
 bear in mind, in reference to these views, and the nomenclature resting 
 upon them. The S0 4 , N0 3 , &c., are called the Salt Radical , which term 
 is often used in chemical books, and is applied equally to "compounds such 
 as the above, or to an element, such as chlorine. It refers to any element 
 or compound that will form an acid when combined with hydrogen, and a 
 salt when united with a metal. There are a great many salt radicals which 
 are compound substances, but which deport themselves in their reactions 
 as elements. One eminent example of a substance of this kind is cyanogen, 
 (CN), which is the salt radical of Prussic acid, and which we will have 
 occasion to notice when treating of the compounds of this acid and the 
 ferro-prussiates, so much used in the dye-house. The symbol of this 
 radical is Cy. 
 
 This view of the constitution of salts is much more simple than that 
 of oxides combining with the acids, and, as it will be apparent, reduces 
 the compound bodies, termed acids and salts, into one great class. 
 
 It also enables us to account for a remarkable law which has been 
 already noticed, namely, that bases, such as metals, always unite with the 
 same number of proportions, or equivalents of acids, or salt radicals. 
 Thus, if we dissolve protoxide of iron, ferrous oxide, in sulphuric acid, 
 one proportion of iron only combines with one proportion of acid, and is 
 represented by FeO, S0 4 H 2 = Fe S0 4 , H 2 0. 
 
 But if we take the peroxide of iron, ferric oxide, and dissolve it in 
 sulphuric acid, we then have three proportions of acid, thus — 
 
 Fe 2 0 3 , 3 S0 4 1I 2 =Fe 2 3 S0 4 II 2 0. 
 
 It must, however, be borne in mind, that both theories require several 
 hypothetical conditions to be taken for granted, to enable us to account 
 for all the phenomena which take place in the actions of one body upon 
 another ; and also, that both these views of the constitution of salts, as to 
 the manner in which the atoms or particles arrange themselves, are liable 
 to objections ; but the latter are more in accordance with observed pheno- 
 
28 
 
 SALT RADICALS. 
 
 mena. We have stated the fundamental principles of these views, both as 
 a general guide to the student in his inquiries into chemical science, and 
 because we will have occasion to refer to them hereafter. But the reader 
 who wishes to obtain more extended information may consult such works 
 as those of Graham, Liebig, Gmelin, Millar, Hoffman, and others, who 
 have given this matter much close attention ; and such research will be 
 found amply to repay any labour and time expended upon it, for on the 
 proper understanding of the fundamental laws of affinity depends, in a 
 great measure, the proper application of chemical science to practical pur- 
 poses, and more especially in such delicate operations, and with such 
 materials, as the animal and vegetable fibres operated upon in a dye- 
 house.. 
 
ELEMENTARY SUBSTANCES. 
 
 Oxygen (0. 16). 
 
 By referring to the table of elements, it will be found that several sub- 
 stances are therein named which many of our practical readers have never 
 heard of. There are, indeed, a number of elements of which little more is 
 known than the fact of their existing in certain compounds ; they have only 
 been seen by the discoverers and a few friends, and are as yet so rare, and 
 found in such small quantities, that under present circumstances their 
 application to any common branch of manufacture is not thought of. Such 
 substances we will therefore pass over with a very short notice, and confine 
 ourselves more to those that are, or so far as their cost and quantities are 
 concerned, may be brought into common use. The name of the element at 
 the head of this chapter is a very familiar term in the dye-house, but is 
 applied so indiscriminately, and so often erroneously, to different substances 
 as to cause a considerable misunderstanding of its real nature and proper- 
 ties. Many of these erroneous applications of the name, and consequent 
 confusion of ideas, will be noticed more appropriately under chlorine, with 
 which gas oxygen is often identified in the dye-house. 
 
 Oxygen exists in Nature both free and combined : when free, it forms 
 a colourless and transparent gas, without taste or smell ; it is a little heavier 
 than common air, of which it forms a part, and is dissolved or absorbed by 
 water, in the proportion of from 3 to 4 per cent, by weight. Its wide range 
 of affinity for other elements, its presence in almost every compound, and 
 the part it plays in nature, invest it with an importance not possessed by 
 any of the other elements. It constitutes more than a fifth part of the 
 atmosphere, as much as eight-ninths of the water, and fully half of the 
 solid crust of the globe ; and it is, besides, a prominent ingredient in all 
 animal and vegetable bodies. The following table shews its numerical 
 importance more precisely: — 
 
 Water has 
 The Air, 
 
 Crust of the Earth, 
 Animals and Vegetables, 
 
 8 oxygen in 9 by weight. 
 3 ,, in 9 ,, 
 
 5 „ in 9 „ 
 
 7 „ in 9 „ 
 
 How to Make Oxygen Gas. — The name oxygen was given to this 
 element from the idea which the old chemists had, that it gave acid pro- 
 perties to its compounds. It was first recognised in this country as a 
 distinct substance by Dr. Priestley, in the year 1774, and about a year after 
 in Sweden, by Scheele, without any previous knowledge of Priestley’s ilis- 
 
30 
 
 HOW TO MAKE OXYGEN GAS. 
 
 covery. It was obtained by Priestley by heating in a retort red oxide of 
 mercury, which is thereby resolved into fluid mercury and oxygen. But 
 
 other and more economical means are now 
 adopted for its preparation, as follows: — 
 An iron bottle is prepared, with an iron 
 tube fitted into the mouth air-tight, form- 
 ing a retort; into this a quantity of black 
 oxide of manganese is put, and the bottle 
 placed with its contents into a good fire, 
 with the open end of the iron pipe dipping 
 into a vessel filled with water. The accom- 
 panying figure shews the bottle in the fire, 
 with the conducting pipe. Care must be taken not to allow any water 
 to get into the bottle. This may be prevented by placing a receiver or 
 Woulff’s bottle between, thus — 
 
 When the bottle becomes red hot, bubbles of gas are seen to rise from the 
 pipe through the water : these bubbles are oxygen gas, and may be col- 
 lected by filling a bottle or jar with water, and holding its mouth down- 
 wards over the extremity of the pipe ; the gas, ascending into the bottle 
 or jar, gradually displaces the water. In explanation of what is taking 
 place within the retort-bottle in the fire, it may be stated that black oxide 
 of manganese is composed of MnQ 2 ; the high heat drives off, or sets at 
 liberty a portion of the oxygen, and the manganese is converted into a lower 
 state of oxidation, so that 3 MnO^ becomes Mn 3 0 4 -f-2 O. 
 
 Another and more rapid method of preparing oxygen is, by taking 
 equal parts of oxide of copper and chlorate of potash, and placing the 
 mixture in a small flask or test tube, fitted with a glass tube, as repre- 
 sented by the annexed cut. When 
 heat is applied by means of a lamp, 
 a rapid evolution of gas takes 
 place, very pure, and without any 
 danger to the operator. One 
 ounce of chlorate of potash, treated 
 in this way, will yield about 500 
 cubic inches of gas. The chlorate 
 of potash is composed of 2 KC10 3 , all the oxygen is set free, and 
 chloride of potassium left. The oxide of copper undergoes no decom- 
 position. The part it plays is not well understood ; but a practical use of 
 its presence in this experiment is to prevent fusion of the salt, which would 
 take place, and is liable to break the vessel used. When the experiment is 
 finished and the flask cold, a little water will dissolve out the chloride of 
 
PROPERTIES OF OXYGEN. 
 
 31 
 
 potassium from the oxide of copper, which, when dried, may be used again 
 for a similar experiment. Peroxide of iron or manganese may be substi- 
 tuted for oxide of copper. The facility that these bodies give to the 
 decomposition of the chlorate is considered catalytic. There are a variety 
 of other means of obtaining this gas, but they need not be detailed. 
 
 Properties of Oxygen.— Oxygen is an eminent supporter of com- 
 bustion. If a candle be placed in an atmosphere of this gas, it burns with 
 intense brilliancy. Sulphur and charcoal being kindled, and placed in 
 oxygen, give a vivid light, and there is formed sulphurous acid with the 
 sulphur, and carbonic acid with the charcoal. If a piece of iron or steel 
 wire be made red hot, and then immersed into oxygen gas, the combination 
 is so rapid that the heat produced causes the iron to scintillate, and the oxide 
 to fuse and drop off like water, sufficiently hot to melt or fuse china and 
 glass. Many other metals burn in the same way as iron in this gas. It is 
 upon this gas depend the processes of combustion and respiration ; and the 
 various functions of organised existence, in all its forms, are essentially 
 connected and sustained through the agency of oxygen. Indeed, there are 
 few operations in chemistry which are not in some way connected with 
 oxygen, so that, under the various heads in which we intend to treat our 
 subject, its nature and properties will be constantly developed. Dyed 
 fabrics, whether wet or dry, suspended in this gas are not affected — a fact 
 for the dyer to .bear in mind when he is identifying this gas with chlorine. 
 
 Hydrogen (H. 1). 
 
 Hydrogen is a gaseous element, never found free or uncombined in 
 Nature, but is easily obtained from some of the compounds of which it is 
 a component. When pure, it is without smell or colour, and is the lightest 
 substance known; if is therefore used for inflating balloons. Its dis- 
 tinctive character as an element was first pointed out by Cavendish, in 
 1766. It exists abundantly in Nature in combination with other elements ; 
 it is a constituent of all animal and vegetable substances ; and, being one 
 of the constituents of water, it enters as such into the composition of almost 
 all compounds. It is from the decomposition of 
 water that hydrogen is generally prepared for 
 experimental purposes. The process is simple. 
 
 By putting some iron or zinc into a retort, and 
 pouring over it a little dilute sulphuric or hydro- 
 chloric acid, the metal dissolves with effervescence, 
 and the gas, in passing off, may be caught in 
 bottles or jars over the pneumatic trough, as 
 described for oxygen. Instead of a retort, a flask 
 or bottle may be used, having a tube fitted by a 
 cork in the mouth of the bottle, as represented by 
 the annexed figure. 
 
82 
 
 WATER. 
 
 The reaction which takes place, by the acid acting on the metal, is, as 
 we have before shewn (page 26), formulated thus — 
 
 S0 4 H 2 + Zn = S0 4 Zn + II 2 . 
 
 We observe here that the change is only the substitution of the metal 
 for the hydrogen in the acid. The use of the water mixed with the acid is 
 to dissolve the salt of zinc formed in the process, which requires a con- 
 siderable quantity of water. From these and similar facts hydrogen is 
 supposed to be a metal existing in a gaseous form. Its chemical character 
 exhibits most of the properties possessed by the metals, and alloys of 
 hydrogen with other metals, particularly paladium, have been obtained. 
 Hydrogen, when prepared in the way described, has a slight smell, which 
 results from impurities in the substances used, generally from a small trace 
 of arsenic or sulphur being in the metal. When iron is used instead of 
 zinc, the smell is still more perceptible. Hydrogen is a combustible gas, 
 and burns with a yellow flame, but does not support combustion. A 
 burning candle immersed in it is instantly extinguished. When mixed with 
 oxygen, and heat is applied, the mixture explodes with a loud report, and 
 water is formed by the union of the gases* Hydrogen does not support 
 life. An animal immersed in an atmosphere of it soon dies. Several 
 attempts have been made to breathe this gas, and some curious effects have 
 been observed; bub from incautiousness in not purifying the gas perfectly 
 before inhaling it, two fatal accidents have followed. All such attempts 
 are extremely foolish. Hydrogen combines with oxygen in two propor- 
 tions, forming the protoxide or water, and peroxide or binoxide, a substance 
 which has strong bleaching properties. 
 
 Water. — The discovery of the true composition of water was made by 
 Cavendish, in 1781, by burning known quantities of oxygen and hydrogen 
 in a dry glass vessel, and observing that water was formed and deposited 
 on the glass, and in quantity exactly equal to the weights of the gases 
 which disappeared. He also found that these gases unite exactly in the 
 proportion of two volumes of hydrogen with one of oxygen, and by weight 
 1 to 8, or as now formulated, 2 to 16. 
 
 Pure water is colourless and transparent, and has neither taste nor 
 smell. It is eminently neutral, having neither acid nor alkaline properties, 
 and does not alter the nature of substances put into it. It often enters, 
 however, into the composition of compounds ; and many substances put into 
 it have the property of decomposing it, and appropriating its elements. 
 
 The statement that water is entirely neutral, and having no action 
 upon matters put into it, may appear doubtful to the practical dyer, as his 
 daily experience teaches him that the waters he uses have a strong effect 
 upon many of the dyes, and that certain kinds of water are better for some 
 of his colours than others, which manifests a difference either in the con- 
 dition or constitution of the water. This difference in water, experienced 
 by dyers, depends upon foreign matters dissolved in it. It would therefore 
 
WATER. 
 
 33 
 
 be a great object for the dyer to obtain pure water ; or, if this is not 
 practicable, to know what the ingredients are that are in the water he is 
 using, so that he may either counteract their effects and escape their conse- 
 quences, or render them subservient to his purpose. The great practical 
 importance of water to the dyer is not only its neutrality, but also 
 its solvent power. The cohesion of solid bodies is overcome, and the 
 particles are diffused through those of the water, and so placed in the best 
 possible condition for combining with the particles of other bodies brought 
 into proximity with them. This may be illustrated by taking two solid 
 substances that have a strong affinity for each other — say tartaric acid and 
 carbonate of soda; mix them together dry, there will be no apparent 
 action ; but if these substances be previously dissolved in water, and the 
 solutions mixed, the action is violent and immediate. It is its great solvent 
 powers that gives us impure water. 
 
 Water is rendered pure by distillation. When boiled it passes off as 
 steam, and when steam is condensed by cooling, it is pure water, provided 
 the impurities which were in the water before boiling do not volatilise 
 at a lower temperature than that of 212°. Gaseous matters are expelled, 
 and such liquids as alcohol, which boil at lower temperatures, are also 
 given off ; but the impurities that are found in common water to affect the 
 dyer are not given off, except these be in the water in great quantities, as 
 in leys, in boiling which some of the soda or potash is carried away with 
 the steam, as already noticed. 
 
 The original source of all our water is from the surface of the ocean : 
 it is evaporated, or vaporised, and carried through the atmosphere in the 
 form of clouds, or in solution, and deposited upon the earth as dew or 
 rain ; in these states it dissolves matters from the atmosphere, such as car- 
 bonic acid, ammonia, &c. ; so that rain water, especially if near towns, is not 
 altogether free of impurities. Nevertheless, when far from towns, or after 
 it has rained for some time purifying the air, rani is the purest water in 
 nature, but the moment it touches the earth it dissolves some solid matters, 
 and becomes contaminated with the ingredients of the soil over or through 
 which it passes, and these ingredients cause the differences experienced by 
 dyers. The nature of the impurities depends upon the immediate source of 
 the water — the nature of the soil or strata of earth through which it has 
 passed ; and as these substances act and react upon the dye-stuffs used, it 
 therefore becomes of the first importance that the dyer should fully com- 
 prehend the character and effects of the substances dissolved in the water 
 he is using. These ingredients are generally lime, magnesia, alumina, 
 potash, soda, iron, copper, sulphuric acid, hydrochloric acid, .and carbonic 
 acid. There are also other substances, which have been found in springs, 
 in more minute quantities, but which we need not enumerate here, as they 
 are not common ; and even some of these given, such as copper, are not 
 often present in waters used in the dye-house. These earthy substances 
 are generally found in the water combined as sulphates, chlorides, or car- 
 bonates. There are also gases present in waters, as atmospheric air, car- 
 
 c 
 
34 
 
 WATER. 
 
 bonic acid, sulphurous acid, &c. The last-named gas is easily detected by 
 the smell, and water could not be used for dyeing containing an appreciable 
 quantity of it. Copper will not be present except in the vicinity of a 
 copper mine, or a copper-ore vein. Iron as a sulphate, or chloride, 
 is often present in very minute quantity; but when the quantity is 
 considerable, the water is not good for many purposes ; and if the 
 water is conveyed through lead pipes, or retained in leaden tanks, a 
 small trace of lead may be detected, which is not only deleterious to 
 the dyer’s operations, but very destructive to health. Two common 
 definitions of the quality of water are hard and soft ; but these expres- 
 sions, so far as regards the dyer, are somewhat ambiguous, and are only 
 useful when alkalies and soaps are to be used. Distilled water is soft and 
 pure, and useful for all purposes of the arts ; but a water may be soft and 
 useful for bleaching and washing, and very deleterious in dyeing; and it 
 may be hard, and yet good for dyeing most colours. Such a term, there- 
 fore, does not denote any particular kind of impurities. If a piece of pure 
 white soap be dissolved in alcohol, not so strong as to form a jelly, and a 
 little of the solution be dropped into water, if the soap curdles the water is 
 hard ; if not, it is soft. If hard, the ingredients are of an acid or an earthy 
 nature, such as carbonic acid, carbonate of lime or iron, sulphate of lime, 
 &c. ; if soft, it may contain alkalies. The ingredients in the water are often 
 so minute that the ordinary tests do not for some time detect them. The 
 best mode of proceeding is to apply the soap test first, as a sort of 
 guide ; next, to try the water with delicately-prepared test papers, and 
 observe whether it has any acid or alkaline reaction; then take a gallon 
 of the water and boil it down to a pint ; put this into a narrow jar, and 
 allow it to settle for a few hours ; pour off the clear liquid into another 
 vessel, and retain for examination the turbid remainder if any : it will 
 most probably be carbonate and sulphate of lime, and a little iron. 
 Carbonate of lime has been held in solution as bicarbonate ; but the 
 boiling decomposes this compound, one proportion of carbonic acid being 
 given off, and the insoluble carbonate precipitates. The sulphate of lime 
 is soluble only in small quantity, so that a little may be precipitated by 
 boiling. To the residue add a few drops of hydrochloric acid, and the 
 carbonate of lime and iron will dissolve with effervescence, while the sul- 
 phate will remain undissolved. A drop or two of gallic acid added to the 
 acid solution will detect iron, by giving a black or bluish colour. A portion 
 of this solution may be taken, and a little ammonia added to neutralise the 
 acid ; iron will give a brown precipitate ; if lime is present, the addition of 
 a little oxalate of ammonia will give a white precipitate. 
 
 The clear portion is now divided into five different portions, and put 
 into small wine or test glasses. 
 
 To one portion is added a few drops of gallic acid, which, if iron be 
 present, will, after standing some time, produce a bluish colour. 
 
 To another portion add a few drops of oxalate of ammonia, which will 
 give a white precipitate if lime is present. This should be heated a little. 
 
WATER. 
 
 35 
 
 To a third portion add a few drops of phosphate of soda, and stir it 
 well. After standing some time, if a white precipitate be formed, this will 
 indicate the presence of magnesia. 
 
 To a fourth portion add chloride of barium : if a white precipitate is 
 obtained, which is not re-dissolved by adding a little pure nitric acid, 
 sulphuric acid is present. 
 
 To the fifth portion add nitrate of silver : if a white precipitate is 
 formed, not re-dissolved by the addition of a little pure nitric acid, then 
 hydrochloric acid is present. 
 
 These tests, and the nitric acid used, of course, must be perfectly pure, 
 or no dependence can be placed upon the results. 
 
 If carbonic acid exists in the water, which it does very commonly in 
 combination with a base, it will be known, as already intimated, by the 
 effervescence caused by the addition of an acid ; but it may exist free ; 
 and the best way to detect it, is to take a separate quantity of the water, 
 without boiling, say a pint, and add to it a little clear lime water; if 
 milkiness appear after standing some time, carbonic acid is present, either 
 free or as bicarbonate of lime. 
 
 If blue litmus paper be reddened, there is free acid present in the 
 water. 
 
 This manner of proceeding, which is very simple, is sufficient to give 
 the dyer an idea of the impurities he has to contend with. Of course, the 
 effects of each of these separately, or together, upon his dye-drugs, will 
 also have to be studied ; but for this we refer to the separate heads under 
 which they naturally fall. Should a more correct investigation be required, 
 such as the exact quantity of each ingredient, this must be done by a 
 regular course of analysis, which, we are afraid, few practical dyers have 
 the apparatus or other means of making. However, with the tests referred 
 to, a near approximation may be come at, by boiling the gallon of water to 
 dryness, and carefully weighing the contents, which will give the whole 
 solid matters in the gallon ; and afterwards, by dissolving this in distilled 
 water, pouring off the solution, and drying the insoluble portion, the 
 quantity of soluble salts, which may be those of potash, soda, magnesia, 
 &c., will be found. The water is tested for these and all the other ingre- 
 dients by the tests given. To the remaining insoluble part a few drops of 
 hydrochloric acid are added, and notice is taken if this produces efferves- 
 cence. This acid solution is then diluted with distilled water, and tested 
 as above : if anything remains insoluble, it is again dried and weighed, 
 and the result will indicate the silica present. 
 
 Water is used in the dye-house principally as a solvent ; but its solvent 
 property depends upon certain laws. The action being the mutual attrac- 
 tions between the solid and fluid, it becomes weaker as the attractions arc 
 satisfied. If, for example, we take a piece of white sugar of lead, and 
 immerse one small point of it in water, the liquid is quickly drawn up into 
 its pores, and adheres to the particles of the salt. If more water than is 
 merely sufficient to wet the particles is allowed to enter, the solid particles 
 
36 
 
 WATER. 
 
 of the salt break down and disappear in the water — in other words, the salt 
 dissolves. But this action of the water upon the salt is limited: it is very 
 powerful at first, but as the salt is diffused through the liquid, the action 
 upon the solid decreases gradually, until the water gets satisfied, and will 
 dissolve no more ; the water is then said to be saturated. 
 
 A general practice in dissolving salts in the dye-house may here be 
 noticed. When dissolving quantities of crystallised salts, such as alum, 
 sugar of lead, &c., the custom is to put the solid crystals into a vessel, and 
 pour water upon them; and a person keeps stirring until the whole is 
 dissolved or the water saturated. This takes up much valuable time, and 
 there is often a remainder of the salt not dissolved for want of time. If, 
 instead of proceeding in this way, the quantity of water which is neces- 
 sary to use be put into the vessel, and the crystals of the salt be suspended 
 upon the surface, the solution would proceed much more rapidly and 
 more economically than any other way. As the particles of water take up 
 the particles of the salt, they become heavier, and sink; other particles 
 take their place, dissolving more of the salt, and sink in turn, so that the 
 action of a constant current of liquid is kept up on the suspended crystals, 
 and always of that portion of the liquid most capable of dissolving. Now, 
 if the crystals of any salt are put into a vessel, and water poured over them, 
 and allowed to remain, they are a very long time in being dissolved, as the 
 water surrounding the crystals becomes saturated and incapable of dis- 
 solving more, and from its weight it remains at the bottom of the vessel. 
 This may be beautifully illustrated by taking three tumblers filled with 
 water, and adding to each an equal weight of crystallised sulphate of 
 copper. In the one let the crystals rest at the bottom, stir the second 
 constantly, and let the crystals in the third be suspended upon the surface 
 of the water, the action will be seen, and the difference in time appreciated. 
 
 In general, hot water dissolves more of a salt than cold water ; but 
 the relation of different dissolving powers of water, at different tempera- 
 tures and for different salts, is very curious. Some salts dissolve equally 
 at all temperatures, such as common salt. Some salts dissolve least in cold 
 water, and increase gradually as the water is heated; others, again, increase 
 rapidly, until the water is at a certain temperature, and then become less 
 soluble ; while other substances, such as lime, dissolve in larger quantity 
 when the water is cold. Thus, 66 gallons water, at 32° Fah., dissolve 1 lb. 
 lime; but it takes 75 gallons at 60° Fah., or 128 gallons at 212°, to produce 
 the same effect ; so that boiling water can contain only about the half of 
 the lime that ice-cold water can. Thus, when .saturated lime water at 60°, 
 which is about the maximum heat of water in summer, is boiled, a quantity 
 of lime is deposited as the heat increases. This is often experienced 
 in the raising of chrome oranges. 
 
 The following table illustrates these remarks, and is of great value 
 to the dyer : — 
 
WATER. 
 
 37 
 
 It will be seen here that if a salt is dissolved in boiling water to satura- 
 tion, and allowed to cool, a great quantity will be deposited either as 
 crystals or powder ; also, if we wish to have a highly-saturated solution, 
 there are certain temperatures better adapted for obtaining it than others. 
 The best means for uniformity is to use the salt dissolved to saturation in 
 cold water, as above stated ; and the dyer, while he uses his solution, say the 
 salts of iron, alum, &c., should know that when he uses the full of a ladle, 
 or pail, or small mug, he is taking exactly so many ounces or pounds of 
 the salt, rather than so many measures, as is generally the case, without 
 reference to the particular strength of the solution. 
 
 The following table of the quantity of a salt dissolved in a gallon of 
 cold water at saturation, will be an example of this : — 
 
 Common salt, 
 Sal-ammoniac, 
 Sulphate of copper, 
 Sulphate of iron, . 
 Sulphate of zinc, . 
 Sulphate of nickel, 
 Sulphate of soda, . 
 Alum, . 
 
 4^1bs. per gallon. 
 
 H 
 
 „ 
 
 n 
 
 7 * 
 
 H 
 
 H 
 
 Comparing this with the diagram above, it will be seen that double the 
 quantity of some of these salts is dissolved in boiling water ; so that a 
 saturated solution of some salts at different temperatures contains different 
 quantities — this the dyer ought to bear in mind. 
 
 Besides the property for dissolving solid bodies, which we have been 
 considering, water, as has been previously said, has also the property of 
 dissolving gases, and holding them in solution. In this case, cold water is 
 a more powerful solvent than hot. Some gases, if held in solution by 
 
38 
 
 INCRUSTATION ON STEAM BOILERS. 
 
 water used for dyeing, would be very deleterious ; and as many of these 
 gases are often floating about in the dye-house, they may be absorbed by 
 the water in small quantities, and be injurious, and the cause of the injury 
 may not be known or thought of. The following are a few of the gases 
 and their solubility in water. 
 
 100 volumes, or cubic inches of water, at 60°, will dissolve about 
 
 253 volumes of sulphuretted hydrogen, weighing 
 
 93-6 grains. 
 
 438 ,, sulphurous acid, 
 
 ?> 
 
 300 
 
 206 chlorine, 
 
 55 
 
 155-7 „ 
 
 100 ,, carbonic acid, 
 
 ?? 
 
 47-2 „ 
 
 76 ,, nitrous oxide, 
 
 55 
 
 75 „ 
 
 Any of these gases in the water will affect colours, and they are all, 
 to some extent, found in the dye-house. 
 
 One gallon is equal to 277 cubic inches, so that each gallon is capable 
 of holding in solution 
 
 259-3 grains of sulphuretted hydrogen. 
 
 189*7 grains of sulphurous acid. 
 
 4:31-3 grains of chlorine. 
 
 130-7 grains of carbonic acid. 
 
 273 grains of nitrous fumes. 
 
 Incrustation on Steam Boilers.— All natural water, except rain, 
 contains small portions of earthy matters in solution, which are not volati- 
 lised by boiling. This is a source of great annoyance and loss where 
 much steam is used. In steam boilers, as the wate$ boils off, these salts 
 accumulate until the water cannot hold more in solution, then the salt 
 deposits or crystallises upon the surface of the boiler. The salts principally 
 found affecting boilers are bicarbonate and sulphate of lime. The former 
 salt is soluble in water in small proportions-, but when the water contain- 
 ing it is brought to a boiling heat, it loses an equivalent of carbonic acid, 
 which passes off with the steam, and leaves carbonate of lime, which is 
 insoluble in water, and precipitates, so that every night, during the non- 
 use of the boiler, this precipitate falls to the bottom of the boiler and 
 forms a crust, so that in a few weeks, according to the quality of the 
 water, a thick layer of carbonate of lime is formed, which hurts the boiler 
 and causes great loss of heat. This kind of precipitate is, however, very 
 easily prevented by placing a perforated pipe along the bottom of the 
 boiler, and when the precipitate accumulates there, blowing off that portion 
 before it hardens; if this be done regularly, no incrustation is allowed to 
 form. It is different, however, when the water contains sulphate of lime : 
 that does not precipitate, but crystallises on the sides of the boiler, and 
 continues until it thickens so as to retard the production of steam, and 
 adheres so firmly as to necessitate its being chipped off by hammers. 
 Upwards of twenty years ago I adopted the following remedy with 
 good results, which was published at the time. The water used for the 
 boiler was carefully tested for the quantity of sulphate of lime it contained, 
 
BINOXIDE OF HYDROGEN. 
 
 39 
 
 and also the quantity of water boiled off was ascertained. A vessel con- 
 taining a known strength of solution of carbonate of soda was placed in 
 connection with the feeding apparatus* and by means of a stop-cock or 
 syphon as much carbonate of soda was allowed to drop into the feed water 
 as was equivalent to the sulphate of lime, this converted the sulphate into 
 the insoluble carbonate of lime, which precipitating was blown off at inter- 
 vals in the same way as stated above. Boilers that had to be emptied, and 
 the crust taken off by hammers every six weeks, were by this means only 
 cleaned out once a year. We have known carbonate of soda thrown into a 
 boiler in quantity when newly filled, in order to prevent incrustations ; but 
 free soda in the water is hurtful to the packing of engines, as a portion is 
 carried off by the steam. 
 
 Binoxide of Hydrogen. — Binoxide of hydrogen is a colourless liquid 
 like water ; it has a metallic taste, and bleaches almost instantly all organic 
 coloured substances. Its preparation is difficult and expensive. It was 
 first obtained by the decomposition of the binoxide of barium, the prepara- 
 tion of which is difficult. There are now known several other methods of 
 obtaining it, but all requiring precaution and chemical skill, that almost no 
 description which our limits permit would enable the student to prepare 
 it by, these are all given in detail by Thenard, the discoverer of the 
 compound, in his Traite de Chemie (vol. i., 6th edition). 
 
 Could there be any means of procuring it readily and cheap, its uses 
 would be invaluable, both as a bleaching agent and also for oxidising, and 
 many other operations in the arts. It is often referred to in proof that 
 oxygen has bleaching properties as well as chlorine — a fact which will be 
 noticed to some extent under that element. 
 
 Hydrogen combines with other elements besides oxygen, giving rise 
 to most important compounds, such as ammonia and the great variety of 
 hydrocarbons, some of which will be treated of under the separate elements 
 with which it combines. 
 
 Nitrogen (N. 14).. 
 
 If a small vessel be floated upon water with a piece of phosphorus 
 set on fire, and a glass jar inverted over it, as represented by the an- 
 nexed figure, the flame is soon extinguished, 
 and the water, when the air within the glass 
 cools, rises into the jar. If you let the 
 whole stand until the white fumes in the glass 
 disappear, the remaining air in the jar will be 
 found to differ entirely from common air: a 
 candle will not burn in it, and an animal put 
 into it would very soon die. This gaseous 
 substance is nitrogen. The atmosphere is com- 
 posed of oxygen and nitrogen ; and the burning 
 phosphorus combines with the former of these gases, forming phosphorous 
 
40 
 
 NITROGEN. 
 
 acid, constituting the white cloud referred to, which is absorbed by the 
 water after a little time. The rising of the water into the jar is to supply 
 the place occupied by the oxygen consumed, and nothing but nitrogen 
 remains. 
 
 This element was first called Azote by its discoverer, Dr. Rutherford — 
 the life-destroyer — from its not having the power of supporting life ; but 
 the name was afterwards changed to nitrogen, on account of its being 
 found to be the basic constituent of nitric acid (aquafortis). Nitrogen 
 has neither taste nor smell, and is rather lighter than oxygen. Its use in 
 the atmosphere is supposed to be for diluting the oxygen; but there is no 
 doubt that other important purposes are served by its presence in the air, 
 although we may be ignorant of them, as it forms an essential constituent 
 of animals and vegetables, and also of many mineral productions. Nitrogen 
 is peculiar for what are termed inert or negative properties. We cannot 
 cause it to combine directly with any other element, as we do oxygen and 
 hydrogen, or hydrogen and chlorine ; nevertheless, it combines with a 
 number of elements, when compounds are being decomposed. 
 
 With oxygen, nitrogen forms a variety of interesting compounds, 
 already alluded to (page 18), but which we will here notice more in 
 detail, particularly those more commonly met with. As already remarked, 
 the atmosphere is a mixture of nitrogen and oxygen, found to be in very 
 nearly the same proportions under all circumstances and at all places, not 
 in chemical union, but maintained in equal mixture by the principle of 
 diffusion. There is a variety of methods for ascertaining the proportions 
 of oxygen and nitrogen in the air : the one just described, .the burning of 
 phosphorus in an inverted jar over water, will suffice as an example. The 
 results of careful investigations into this subject give as the constitution of 
 the atmosphere in 100 parts — 
 
 21 Oxygen. 
 
 79 Nitrogen. 
 
 But from the constant evaporation of water from the sea and surface of 
 the earth, and the production, by many causes, of carbonic acid gas, which 
 finds its way into the atmosphere, the air always contains a small and 
 variable portion of those ingredients, which, being taken into account, 
 
 makes, as a general average, the composition — 
 Oxygen, .... 
 
 . 20 
 
 Nitrogen, .... 
 
 . 79 
 
 Yap our of water, . 
 
 . 0-9 
 
 Carbonic acid, 
 
 0-1 
 
 100-0 
 
 The dyer cannot fail to have observed a thin crust of solid matter 
 upon the surface of his lime solution, bleaching liquor, and blue vats. 
 This crust is the carbonate of lime, and is caused by the carbonic acid in 
 
NITROGEN TRIOXIDE, OR NITROUS ACID. 
 
 41 
 
 the air combining with the lime, and forming an insoluble carbonate. 
 The presence of this gas in the air has no deleterious effects in the dye- 
 house, so far as we know, except its combining with caustic alkalies, if 
 exposed, and deteriorating them. 
 
 The oxygen of the atmosphere plays a very prominent part in the dye- 
 house ; and the knowledge of the true constitution of the air will make 
 many of these phenomena better understood. This gas not being in 
 chemical union with the nitrogen, there is no chemical force retaining 
 and preventing it from acting upon other bodies, when brought under 
 its influence. 
 
 The principal compounds formed between nitrogen and oxygen are — 
 
 Nitrogen monoxide, or protoxide of nitrogen, 
 Nitrogen dioxide, or deutoxide of nitrogen, . 
 Nitrogen trioxide, or nitrous acid, 
 
 Nitrogen tetroxide, or peroxide of nitrogen, . 
 Nitric acid (aquafortis), .... 
 Nitrogen pentoxide, 
 
 . N 2 0 
 
 . NO 
 
 . n 2 0 3 
 
 . N 2 0 4 ,orN0 2 
 . HNO3 
 
 . n 2 o 5 
 
 Some of these being of no known importance in the dye-house, 
 we need do little more than refer to the condition in which they may 
 be found. 
 
 Protoxide of Nitrogen — Nitrogen Monoxide — is a gaseous body, 
 and is easily obtained by heating nitrate of ammonia in a retort, as 
 described for obtaining oxygen (page 30), and collecting the gas as it 
 escapes over water. It is known under the appellation of laughing gas. 
 
 Binoxide of Nitrogen — Dioxide — is also a gaseous body, and is 
 evolved when metals are being dissolved in nitric acid. When dissolving 
 iron or copper in nitric acid, in open vessels, as is done for the preparation 
 of mordants, a dense red gas is seen to escape during the process. This 
 red gas is produced by the binoxide of nitrogen combining with the oxygen 
 in the atmosphere, and forming a peroxide; but when the metal is dissolved 
 in a retort, or other close vessel, as described for hydrogen, and the gas 
 collected in a glass jar, it is found perfectly colourless. The following is 
 the reaction which takes place when a metal is being dissolved in nitric 
 acid and dioxide of nitrogen evolved. Every three equivalents of metal, 
 say copper, require eight equivalents of acid, two of which are decomposed 
 as follows : — 
 
 8 IINO3 + 3 Cu = 4 II 2 0 + 3 (Cu 2 N0 3 + 2 NO). 
 
 Nitrogen Trioxide, or Nitrous Acid. — This acid is prepared by 
 taking four volumes of the binoxide of nitrogen, adding to them one 
 volume of oxygen, and exposing this mixture to a low degree of cold : 
 the gases, under these circumstances, unite, and form a greenish-coloured 
 liquid, which is nitrous acid. As may bo supposed, from the manner in 
 
42 
 
 NITRIC ACID. 
 
 which it is prepared, this substance is very volatile. If put into water it 
 is decomposed. But it can be obtained by several means, in combination 
 with bases, such as potash, soda, lead, &c., with which it is more stable. 
 
 Nitrogen Tetroxide, or Peroxide of Nitrogen. — This compound 
 is formed when the binoxide of nitrogen is allowed to escape into the 
 atmosphere, and constitutes the red fumes observed when dissolving iron 
 or copper in nitric acid. It is also obtained by distilling nitrate of lead 
 in a retort, and allowing the fumes to pass into a bottle or flask kept cool 
 by placing it in a freezing mixture, such as snow and salt. It condenses in 
 this vessel, and forms a reddish -yellow liquid, which, however, passes off 
 as gaseous fumes by the slightest elevation of temperature. These fumes 
 are very corrosive : they are fatal to animal and vegetable life, and rapidly 
 destroy all colours, and also the fibres of the cloth of yarn exposed to 
 their action. The dissolving of metals in nitric acid should, therefore, 
 never be carried on within or near the dye-house, or any place where 
 goods are exposed. We have known a little inattention to these precautions 
 destroy the labour of several days, and this, too, when the destructive 
 agent was hardly perceptible to the senses, although its odour is amongst 
 the most easily detected of gaseous compounds. This gas is also very 
 suffocating and hurtful to health, and care should be taken that it is not 
 breathed. It is its presence in nitric alcid which gives that acid the 
 reddish-brown colour which the aquafortis of commerce often has. 
 
 Nitrogen Pentoxide. — We have already stated that the compound 
 NO s was a sort of hypothetical substance to suit the theory of acids 
 uniting with oxides ; but when this theory was proven in error, the exist- 
 ence of a pentoxide was a desideratum, which, however, is not so now: 
 such a compound may be formed by the action of dry chlorine on per- 
 fectly dry silver nitrate. It forms colourless needle-shaped crystals. It 
 is a very unstable compound, decomposing at ordinary temperatures. It 
 stands in a similar relation to nitric acid that Nordhausan oil of vitriol 
 does to sulphuric acid. Its symbol by the new notation is N 2 0s. When 
 combined with water it forms nitric acid. 
 
 Nitric Acid. — This acid exists abundantly in Nature, in combination 
 with other substances forming nitrates. We have said before that nitrogen 
 and oxygen do not combine directly in the same manner as oxygen and 
 hydrogen. There is no doubt, however, that the nitric acid which is found 
 united with bases in Nature has been the result of the union of the oxygen 
 and nitrogen of the atmosphere. When a quantity of hydrogen is mixed 
 with nitrogen in an open vessel and ignited, it burns rapidly in contact 
 with the oxygen of the air, forming water; and the water thus formed is 
 found to contain nitric acid. If electric sparks be passed through air, 
 confined in a vessel above a solution of an. alkali, a portion of the alkali 
 is converted into a nitrate. Pain which falls during a thunderstorm, 
 
NITRIC ACID. 
 
 43 
 
 almost always contains nitrate of ammonia. Ammonia is always being 
 found in the air by the decomposition of animal and vegetable sub- 
 stances, and it is absorbed by the watery vapour;, so that when electric 
 currents pass through the air during a thunderstorm, the nitric acid 
 formed combines with this ammonia, forming a nitrate. In warm climates, 
 where electric currents are abundant, and the quantity of ammonia in the 
 air is considerable, the formation of nitrate of ammonia is proportion- 
 ably great; and this, being washed down by the rain in porous lime- 
 stone soils, is decomposed by the nitric acid combining with the lime, and 
 also with potash and soda, which are general constituents of soils, forming 
 nitrates with these bases, and the ammonia is accordingly liberated, either 
 to be given to the air again, or taken up by plants, as a constituent of their 
 food. & In this way immense beds of nitrates have been formed in the East 
 Indies and in South America. In Chili and Peru there are found large 
 deposits of nitrate of soda upon the surface of the soil. Great quantities of 
 nitrate of potash and soda are imported from these localities for the various 
 manufacturing purposes in this country, where they are now extensively 
 applied. The nitrate of lime and other earths are converted into nitrate 
 of potash, by mixing them with carbonate of potash before sending them 
 to this country. 
 
 Nitric acid is prepared from the nitrate of potash or soda, by decom- 
 posing it with sulphuric acid. This may be done on a small scale by 
 putting a little of any of these salts into a retort, adding some sulphuric 
 acid, and then applying heat. The beak of the retort is inserted into a 
 receiver, which must be kept cool by causing cold water to drop upon it. 
 The arrangement of the apparatus is indicated by the following figure. 
 
 At the beginning of this experiment, red fumes of peroxide or 
 tetroxide of nitrogen come off ; but soon after a colourless liquid is seen 
 to distil over, and drop into the receiver — this is nitric acid. The reaction 
 which takes place may be represented by the following formula : 
 
 NaNO s + S0 4 H 2 ;= HNaS0 4 + HNO s . 
 
 Nitrate of soda is now more generally used than potash, being cheaper; 
 and having a lower combining equivalent, more nitric acid is obtained from 
 a given weight. Thus, 100 lbs. of nitrate of potash give 62 lbs. of acid ; 
 
44 
 
 NITRIC ACID. 
 
 while 100 lbs. of nitrate of soda give 74 lbs. The best proportion of 
 sulphuric acid to use with nitrate of potash is two equivalents, whereas 
 less suffices with nitrate of soda. 
 
 Nitric acid is generally prepared, on the large scale, in iron cylinders, 
 placed so that a fire plays round them. Into these cylinders are put the 
 materials ; and the acid vapours which are distilled over are conveyed to 
 the condensing apparatus by glazed earthenware pipes. 
 
 The nitric acid of commerce has generally a light brown colour, 
 caused, as before stated (page 42), by having a little peroxide of nitrogen 
 in it. Sir H. Davy drew out the following table of proportions of nitrous 
 gas contained in this acid, from its shades of colour. Thus, in 100 
 parts — 
 
 Colour. 
 
 Real Acid. 
 
 Water. 
 
 Peroxide of 
 Nitrogen. 
 
 A pale yellow has 
 
 90-5 
 
 8-3 
 
 1-2 
 
 A bright yellow has 
 
 88-9 
 
 8-1 
 
 2-9 
 
 A dark orange has 
 
 86*8 
 
 7-6 
 
 5-5 
 
 A light olive has 
 
 86 
 
 7*5 
 
 6-4 
 
 A dark olive has 
 
 85-4 
 
 7-5 
 
 7-4 
 
 A bright green has 
 
 84-8 
 
 7-4 
 
 7-7 
 
 A blue green has 
 
 88-6 
 
 7-4 
 
 8 
 
 This table must be considered to refer only to strong acid, for the colour 
 is changed by dilution. Thus, when water is added to the dark orange- 
 coloured acid, it changes it to a greenish -yellow. 
 
 Exposure to the sun’s light produces change of colour, by decomposing 
 the acid, and liberating peroxide of nitrogen, which remains dissolved in 
 the acid. A little oxygen gas is at the same time evolved; and, if the 
 bottle is stoppered, will either drive out the stopper or burst the bottle, a 
 fact too often experienced. The great effect of light upon this acid may 
 be tried by placing a little of the colourless acid in the rays of the sun, and 
 observing the change that follows ; this will shew the propriety of keeping 
 nitric acid always in the dark. Neither should it be exposed to the air, by 
 leaving the stoppers out of the bottles or carboys, as it thereby loses its 
 strength rapidly. 
 
 The nitric acid, formed as described, is often contaminated with iron 
 from the retorts, and also with sulphuric and hydrochloric acids, from a 
 little common salt and other impurities being in the nitre used. It is 
 purified from these matters by redistilling in glass retorts. The acid 
 coming off first in the distillation contains some hydrochloric acid; then 
 nothing but pure nitric acid passes over, until nearly three-fourths of this 
 acid is distilled. But if the operation be pushed further, there is danger 
 of impurities passing over. Of course, what remains in the retort contains 
 the most of the impurities. 
 
NITRIC ACID. 
 
 45 
 
 Sometimes the quantity of impurities in the nitric acid of commerce 
 is very considerable, and very deleterious to the dyer’s opertions. The 
 general test applied to this acid in the dye-house is the specific gravity, 
 taken by Twaddell’s hydrometer ; but density may be given to the acid by 
 dissolving a little nitre in it, or adding sulphuric acid. We have seen 
 nitric acid, with 8 per cent, of sulphuric acid, giving it a high specific 
 gravity. We have also 'met it in commerce with as much as 5 per cent, 
 hydrochloric acid. The presence of either of these acids is disadvan- 
 tageous for the preparation of many of the mordants, as will be noticed 
 under the proper heads. 
 
 When nitric acid contains nitre , or any other salt dissolved in it, the 
 impurity may easily be detected by evaporating to dryness a little of the 
 acid, either upon a piece of glass or a porcelain plate : when the acid is 
 pure, no residue is left. 
 
 The presence of sulphuric acid is detected by diluting a small portion 
 of the acid with four or five times its volume of distilled water, and adding 
 a little of a solution of nitrate of barytes, which will give a white pre- 
 cipitate if sulphuric acid is present. 
 
 Hydrochloric acid, or chlorine, may be detected by adding a little 
 nitrate of silver in solution to the dilute acid, which will also give a white 
 precipitate if any hydrochloric acid be present. 
 
 Iron is detected by adding a little gall water to the dilute acid — a 
 bluish-black colour then appears ; or, if on evaporating a small portion of 
 the acid there is a residue of a brown colour, it indicates the presence of 
 iron. 
 
 After having tested for the presence of these substances, and finding 
 the acid pure, or nearly so, then the specific gravity may be taken as a 
 further certainty of the value of the acid. This varies much with the acids 
 of commerce, but is generally about 1*300 = 60° Twaddell, although it 
 may be made as high as 1*500 = 100° Twaddell. Nearly all the hydro- 
 meters used in this country are those known as Twaddell’s, which is an 
 arbitrary scale. The true specific gravity may be reduced to Twaddell’s, 
 by dividing the fractional figures by 5, as will be observed from the above. 
 But in trying the acids by a Twaddell’s hydrometer, the above rule is to 
 be reversed: we then multiply the degree of Twaddell by 5, add 1000, 
 and divide the sum by 1000. Thus, supposing the specific gravity to be 
 60 ° of Twaddell, then 60 X 5 = 300 ; which, increased by 1000, becomes 
 1300 ; and this, divided by 1000, gives 1*300, the true specific gravity: or 
 say 64 ° Twaddell, which is a common number, then (64 X 5 = 3*20) + 
 1000 = 1*320 specific gravity. The following table shews the quantity of 
 acid in 100 parts, which may be called ounces or pounds, or any weight 
 convenient, according to the true specific gravity. 
 
46 
 
 NITRIC ACID. 
 
 , TABLE OF THE QUANTITY OF ACID IN 100 PARTS 
 BY WEIGHT. 
 
 Specific Gravity. 
 
 Acid in 100 parts. 
 
 Specific Gravity. 
 
 Acid in 100 
 
 1-5000 
 
 100 
 
 1-3376 
 
 58 
 
 1-4980 
 
 99 
 
 1-3323 
 
 57 
 
 1-4960 
 
 98 
 
 1-3270 
 
 56 
 
 1-4940.. 
 
 97 
 
 1-3216 
 
 55 
 
 1-4910 
 
 96 
 
 1-3163 
 
 54 
 
 1-4880 
 
 95 
 
 1-3110 
 
 53 
 
 1-4850 
 
 94 
 
 1-3056 
 
 52 
 
 1-4820 
 
 93 
 
 1-3001 
 
 51 
 
 1-4790 
 
 92 
 
 1-2947 
 
 50 
 
 1-4760 
 
 91 
 
 1-2887 
 
 49 
 
 1-4730 
 
 90 
 
 1-2826 
 
 48 
 
 1-4700 
 
 89 
 
 1-2765 
 
 47 
 
 1-4670 
 
 88 
 
 1-2705 
 
 46 
 
 1-4640 
 
 87 
 
 1-2644 
 
 45 
 
 1-4600 
 
 86 
 
 1-2583 
 
 44 
 
 1-4570 
 
 85 
 
 1-2523 
 
 43 
 
 1-4530 
 
 84 
 
 1-2462 
 
 42 
 
 1-4500 
 
 83 
 
 1-2402 
 
 41 
 
 1-4460 
 
 82 
 
 1-2341 
 
 40 
 
 1-4424 
 
 81 
 
 1-2277 
 
 39 
 
 1-4385 
 
 80 
 
 1-2212 
 
 38 
 
 1-4346 
 
 79 
 
 1-2148 
 
 37 
 
 1-4306 
 
 78 
 
 1-2084 
 
 36 
 
 1-4269 
 
 77 
 
 1-2019 
 
 35 
 
 1-4228 
 
 76 
 
 1-1958 
 
 34 
 
 1-4189 
 
 75 
 
 1-1895 
 
 33 
 
 1-4147 
 
 74 
 
 1-1833 
 
 32 
 
 1-4107 
 
 73 
 
 1-1770 
 
 31 
 
 1-4065 
 
 72 
 
 1-1709 
 
 30 
 
 1-4023 
 
 71 
 
 1-1648 
 
 29 
 
 1-3978 
 
 70 
 
 1-1587 
 
 28 
 
 1-3945 
 
 69 
 
 1-1526 
 
 27 
 
 1-3882 
 
 68 
 
 1-1465 
 
 26 
 
 1-3833 
 
 67 
 
 1-1403........ 
 
 25 
 
 1-3783 
 
 ! 66 
 
 1-1345 
 
 24 
 
 1-3732 
 
 65 
 
 1-1286 
 
 23 
 
 1-3681 
 
 64 
 
 1-1227 
 
 22 
 
 1-3630 
 
 63 
 
 1-1168 
 
 21 
 
 1-3579 
 
 62 
 
 1-1109 
 
 20 
 
 1-3529 
 
 61 
 
 1-1051 
 
 19 
 
 1-3477 
 
 60 
 
 1-0993 
 
 18 
 
 1-3427 
 
 59 
 
 1-0935 
 
 17 
 
NITRIC ACID. 
 
 47 
 
 Specific Gravity. 
 
 Acid in 100 parts. 
 
 Specific Gravity. 
 
 Acid in 100 parts. 
 
 1 - 0878 . 
 
 16 
 
 1-0430 
 
 8 
 
 1 - 0821 ....... 
 
 15 
 
 1-0375 
 
 7 
 
 1-0764 
 
 ........ 14 
 
 1-0322 
 
 ........ 6 
 
 1 - 0708 ....... 
 
 ........ 13 
 
 1-0267 
 
 5 
 
 1-0651 
 
 ........ 12 
 
 1-0212 
 
 4 
 
 1-0595 
 
 11 
 
 1-0159 
 
 3 
 
 1 - 0540 ....... 
 
 10 
 
 1-0106 
 
 2 
 
 1-0485 
 
 .9 
 
 1-0053 
 
 1 
 
 The presence of free nitric acid in a solution is easily ascertained by 
 the production of red fumes when a metal is put into it, such as iron or 
 copper; or by adding to the solution supposed to contain it a drop of 
 sulphate of indigo, and heating the solution to the temperature of boiling; 
 the indigo will be discoloured if nitric acid is present. But if the acid is 
 combined with a base, such as soda or potash, this test will not answer. 
 In that case, the best mode of proceeding is to put a little sulphuric acid 
 into the liquid suspected, and then to add a crystal of sulphate of iron 
 (copperas). If nitric acid be present, a ring of an olive-brown coloured 
 liquid will form round the crystal as it dissolves ; and by applying heat 
 the well-known smell of nitrous fumes is felt. By these simple means the 
 dyer can easily ascertain if nitric acid is present, either free or combined, 
 in any compound with which he is working. 
 
 Small portions of nitric acid is a common impurity in vitriol of com- 
 merce, and is very hurtful for some operations to which it is applied in the 
 dye-house : this can be detected by sulphate of indigo, as stated above ; or 
 by adding a few drops of a solution of sulphate of iron, a dark colour is 
 produced when the slightest portion of nitric acid is present. 
 
 The action of nitric acid on the different metals will be noticed under 
 the proper heads ; but one remarkable circumstance connected with this 
 class of action must have been observed by most dyers when dissolving 
 iron — namely, that on putting the iron into the aeid, it often remains with- 
 out any action : when this occurs with new acid, complaints are made that 
 the acid is bad or weak, or that something is wrong which prevents it dis- 
 solving the iron ; and not unfrequently have we seen carboys of acid 
 returned on this account. We had a sample of such acid sent us to test for 
 being bad, and found it to stand in specific gravity T425, and to contain 
 a mere trace of salts and sulphuric acid, with OT per cent, of hydrochloric 
 acid. It was a strong and comparatively pure nitric acid. The cause of 
 the iron not being acted upon, is from a condition which iron is known to 
 assume, termed the passive state ; in which condition aeids do not act upon 
 it. Strong and pure nitric acid places the iron in this state, and therefore 
 it is not dissolved till the acid is diluted, or heat applied. We cite tho 
 above case as an illustration of the value a little attention to chemical 
 principles would be in many dye-houses, not only in saving money, but 
 also preventing the manufacturer being necessitated either to adulterate or 
 dilute his acid, in order to preserve a good and profitable customer. 
 
48 
 
 AMMONIA. 
 
 Nitric acid is very corrosive, from which property it was named aqua- 
 fortis. It destroys all organic bodies, both vegetable and animal. It 
 converts vegetable matter into oxalic, carbonic, and several other acids. 
 Animal substances are acted upon by this acid, producing the yellow- 
 coloured compounds, observed when it comes in contact with the skin or 
 nails. It should be used at all times with great care. 
 
 Ammonia. — Nitrogen combines with hydrogen, and forms a very im- 
 portant compound, ammonia ; composed of one proportion of nitrogen 
 and three hydrogen, NH 3 . Ammonia is abundantly obtained from the 
 destructive distillation of organic matters containing nitrogen, such as 
 bones, horns, skins, blood, and other animal matters. It is also obtained 
 as a product in the distillation of coal. When animal matters are decom- 
 posed by burning or putrefaction, ammonia is formed, and produces the 
 disagreeable smell which these operations generally give. 
 
 The ammoniacal liquors obtained from the distillation of coal, or by 
 distilling animal matters, are saturated with hydrochloric acid, which 
 converts the ammonia into hydrochlorate of ammonia (sal-ammoniac), 
 which crystallises in a very impure state. These crystals are collected 
 and put into iron pots, set in a furnace lined with tire tiles, and having a 
 large cover or head of lead fitted to them. Fire is applied to the pots, the 
 sal-ammoniac sublimes and collects as a crust upon the leaden top, from 
 which it is removed from time to time. 
 
 Ammonia is prepared by mixing equal parts of slaked lime and sal- 
 ammoniac, and applying heat. The lime combines with the hydrochloric 
 acid, and the ammonia passes off as a gas, and is conducted by a pipe into 
 water, with which it combines, and forms liquid ammonia. 
 
 If the crude liquor, obtained by the distillation of coal or animal 
 matters, is not to be converted into liquid ammonia, sulphuric acid is used 
 instead of hydrochloric, forming a sulphate of ammonia which is crystal- 
 lised,- and is extensively used for making up manures, and also for several 
 operations in calico-printing. 
 
 Ammonia, long known as hartshorn, is a strong alkali, and has a very 
 pungent, sharp smell. It is an exceedingly valuable re-agent in the labor- 
 atory, both as a test and for making many useful salts by combination with 
 acids, the greater number of which are volatile. These salts are, however, 
 not much used in the dye-house. Ammonia is sometimes used for the 
 preparation of archil, for bringing out the colour. Its action upon the 
 colouring matter of the woods is very powerful. It is the presence of 
 ammonia and some of its salts in urine, which gives that fluid the peculiar 
 properties for which it is used in the dye-house — as a cleansing agent for 
 woollen, and for raising the colour of a decoction of logwood. 
 
 Nitrogen also combines with some of the other elements, forming 
 compounds more or less interesting according to their applications, some 
 of which will be noticed when treating of the elements with which these com- 
 binations take place. It is a common element in many organic compounds. 
 
CHLORINE. 
 
 Chlorine (35, 46). 
 
 Chlorine was discovered by Scheele, in 1774, and was called by 
 dephlcgisticated muriatic acid. About eleven years after this, Berthollet 
 considered that he had found it to be a compound of muriatic acid with 
 oxygen, and hence termed it oxygenised muriatic acid — a name which was 
 afterwards contracted into oxymuriatic acid; bleachers further contracted 
 it to oxygen. In 1811, Sir EL Davy discovered it to be a simple or elemen- 
 tary substance, and gave it the name of chlorine, from its having a greenish- 
 yellow colour. Chlorine has a very strong, suffocating smell, occasions 
 violent coughing and debility, and gives an astringency to the mouth : 
 therefore breathing it ought to be avoided as much as possible. 
 
 Chlorine exists in Nature in large quantities, in combination with 
 other elements, particularly sodium, forming chloride of sodium (common 
 salt). It is from this source that it is prepared for use in the arts. If we 
 mix about 8 parts of salt with 6 parts of black oxide of manganese, and 
 add to this about 3 parts of sulphuric acid, a portion of the oxygen of the 
 manganese combines with the sodium, and the chlorine is set at liberty- 
 The action may be thus defined : — 
 
 him 
 
 2 CINa, MnO 2 -f 2 S0 4 H 2 = S0 4 Mn, S0 4 Na 2 2 H 2 0, 2 Cl. 
 
 Two common salt,.... 
 
 i cl 
 
 (Sodium 
 /Mn 
 
 Peroxide manganese, 1 0 ^ 
 
 (O, 
 
 r el 
 
 Two proportions sul- SO 4 .... - Sulphate soda. 
 
 phuric acid, . 
 
 h 2 ... 
 
 lso 4 . 
 
 Chlorine gas. 
 
 Water. 
 
 Water. 
 
 Sulphate manganese. 
 
 Chlorine is also manufactured from hydrochloric acid. This acid 
 being obtained as a waste product in the manufacture of soda is utilised 
 for this purpose ; when four equivalents of liquid hydrochloric are put upon 
 one equivalent of peroxide of manganese and heat applied, there is formed 
 one equivalent of perchloride of manganese, and two equivalents of 
 chlorine are given off, shewn thus — 
 
 4 equivalents IIC1, 
 
 1 peroxide 
 gauese,.... 
 
 -f 
 
 2 II 
 
 2 ClX 
 
 Chlorine 
 
 2 H \ 
 
 
 2 Cl^C 
 
 
 
 Wfitor. 
 
 0 ... 
 
 X Water. 
 
 Mn. 
 
 . per CIMn. 
 
 Other peroxides may be used instead of manganese for the same purpose. 
 
50 
 
 CHLORIC ACID. 
 
 Chlorine combines with almost all the elements, and forms with them 
 a series of compounds as numerous as they are important. Its power of 
 combining with, and decomposing colouring substances, is remarkable, 
 and has given it a prominent standing in the arts. It combines with 
 oxygen in various proportions, giving origin to several compounds, both 
 useful and interesting to the dyer. 
 
 Chlorine protoxide, or hypochlorous acid, 
 Chlorine trioxide, or chlorous acid, 
 
 Chloric acid, 
 
 Perchloric acid, 
 
 . C1,0. 
 
 • C1 2 0 3 . 
 
 . HC10 S . 
 . HC10 4 . 
 
 Chlorine Protoxide, or Hypochlorous Acid. — This is a very 
 unstable compound, supposed to be connected with many of the operations 
 of bleaching. It may be prepared by diffusing some red oxide of mercury 
 in a little water, and then introducing it into a bottle previously filled 
 with chlorine gas. The chlorine is rapidly absorbed, and combines with 
 both the mercury and oxygen. It produces, with the former, an insoluble 
 oxychloride, and with the latter it forms hypochlorous acid, which is in 
 solution in the water. This solution has a yellow colour, smells like 
 chlorine, and bleaches powerfully; but it cannot be kept for any length of 
 time, even in the cold, but passes into chlorie acid. Hypochlorous acid 
 combines with alkaline bases, and forms hypochlorites, which also possess 
 bleaching powers. It is generally supposed that when chlorine gas is 
 passed through solutions of the alkalies, such as potash and soda, a similar 
 decomposition takes place as that described of the oxide of mercury, and 
 that the hypochlorite of the alkali is the bleaching salt formed. This salt 
 is decomposed by heat. 
 
 Chlorous Acid may be prepared by adding strong sulphuric acid to 
 chlorate of potash. The process is a dangerous one, and we would not 
 advise any workman not experienced in chemical manipulation to try it, 
 especially as neither the acid nor its salts are of any great importance. 
 The acid is a gaseous body of a yellow colour ; it combines with bases, 
 and forms salts termed chlorites. These also possess bleaching powers, 
 and are very unstable. 
 
 Chloric Acid. — This acid is not of any value in a separate form, and 
 is obtained with difficulty ; but it is easily enough obtained in combina- 
 tion. When chlorine gas is passed through a solution of caustic potash, it 
 is rapidly absorbed. This, by standing some time, or by the application 
 of a little heat, becomes converted into a mixed salt of chloride of potas- 
 sium and chlorate of potash. Thus — 
 
 6 HKOC1 = KC10 S , 5 KC1 + 3H 2 0. 
 
 The chlorate of potash being less soluble than the chloride, it is easily 
 separated by crystallising. Chlorate of potash has very strong detonating 
 
HYDROCHLORIC ACID. 
 
 51 
 
 powers, and should be used with great eare by the student, especially 
 when mixing it with any other substance, as these compounds are often 
 explosive. It is extensively used for lucifer matches. We are not aware 
 that this salt is used to any extent as yet in the dye-house ; but from the 
 property it possesses of giving off oxygen easily, it may be made very 
 useful in many operations, where oxydation is an object. It is extensively 
 used in calico print-works, along with steam, for producing what is termed 
 ageing. 
 
 Chloric acid combines with other bases besides potash. These com- 
 pounds were for a long time, and are occasionally still termed hyper - 
 oxymuriates. 
 
 Perchloric Acid is formed from the ehlorate of potash. It may 
 be obtained in combination with potash, by acting upon the above-named 
 salt with nitric acid, and putting the whole afterwards into a small portion 
 of boiling water : on cooling, the perchlorate of potash separates in 
 crystals. The acid may be separated from the base by boiling it with 
 fiuosilicic acid, when the perchloric acid remains in solution. It is also 
 obtained by the action of strong sulphuric acid upon perchlorates. The 
 pure acid is a colourless oily liquid, and fumes strongly in the air. It is a 
 powerful oxidising agent, and will set fire to paper, charcoal, and other dry 
 organic substances. It produces a painful burn when it touches the skin, 
 and dropped into water it hisses like hot iron. It is not yet of much use 
 in the arts, and it has no bleaching properties. It forms salts by com- 
 bining with the metals. Its potash salt is the least soluble salt of that 
 metal known. 
 
 Hydrochloric Acid, — Chlorine unites with hydrogen, and forms an 
 important compound, hydrochloric acid (muriatic acid). It is a gaseous 
 substance, very soluble in water, in which state it is used, and has been 
 known since a very early period in history under the names of marine acid , 
 spirit of salt , &c. Hydrochloric acid is easily obtained by the action of 
 sulphuric acid on common salt. It is prepared on the large scale, by 
 pouring vitriol on common salt, in a retort furnaee prepared for the pur- 
 pose ; the fumes passing off are absorbed by water, which thus becomes 
 the liquid hydrochloric acid of commerce. It is afterwards purified and 
 concentrated by distillation. The reaction going on during the preparation 
 may be thus represented : — 
 
 2 NaClS0 4 II 2 = Na 2 SO, 2 C1H. In liquid 2 CHI, 11*0. 
 
 The sulphuric acid is generally used in a diluted state, so that there 
 is always a quantity of watery vapour passing off with the gas. This acid 
 combines with bases, and forms a series of important salts. That from 
 which it is obtained — viz., chloride of sodium, is a good example. It used 
 to be matter of inquiry, as we have before stated, whether this acid was 
 capable of combining with bases, or if it is not decomposed, and water 
 
52 
 
 HYDROCHLORIC ACID. 
 
 formed along with the chloride of the base. As for instance, if hydro- 
 chloric acid be added to nitrate of silver, a white precipitate is formed, 
 which, if collected and analysed, will be found to be composed of chlorine 
 and silver. AgCl, the action having been — 
 
 Nitrate of 
 silver, 
 
 Hydrochloric 
 
 acid, 
 
 (NO,- — 
 
 —^Nitric acid. 
 
 
 
 
 
 (CL. 
 
 — Chloride of silver. 
 
 But if we dissolve a piece of zinc in hydrochloric acid, and evaporate to 
 dryness, we get a white powder, which, on analysis, will give zinc, chlorine, 
 and water, in single equivalents. The question then is, whether these 
 elements do not arrange themselves — 
 
 Water. 
 
 Chloride of zinc. 
 
 Forming chloride of zinc with water. 
 
 Or as 
 
 Hydrochloric acid. 
 
 Oxide of zinc. 
 
 Forming muriate of zinc. 
 
 We have, at the risk of repetition, introduced this here, knowing that 
 there is still confusion in these names among practical men, and have only 
 again to state that all called muriates are and should be properly termed 
 chlorides. Authors used to make a distinction, and call salts that are in 
 union with water, such as the zinc salt above, muriates, and only dry salts, 
 as that of silver, chlorides. The terms, when thus understood, may be used 
 synonymously, so that no confusion need occur on that head. When 
 hydrochloric acid is exposed to the air it emits white fumes, which are 
 hydrochloric acid gas with a little watery vapour ; hence exposure weakens 
 the acid, and should be avoided as much as possible in the dye-house. 
 This gas, besides, corrodes rapidly any substance it comes into contact 
 with, and destroys fabrics and colours. It is a colourless acid when pure, 
 but exposure to the light renders it of a yellow colour ; strong sunshine 
 decomposes it, and such exposure should be avoided. 
 
 The common impurities in this acid are iron, sulphuric acid, and 
 sulphurous acid. The iron may be detected by adding to a little of the 
 dilute acid a drop of gallic acid. Sulphuric acid may be detected by adding 
 a solution of chloride of barium to some of the acid diluted with distilled 
 water, which gives a white precipitate with sulphuric acid. If the clear 
 solution filtered from this test be boiled with a little nitric acid, any 
 sulphurous acid will be converted into sulphuric acid, which will be pre- 
 
HYDROCHLORIC ACID. 
 
 53 
 
 cipitated by the barium, and its presence detected. Different chloride 
 salts, such as common salt, are sometimes found in hydrochloric acid, 
 which give weight and specific gravity. This admixture may be detected 
 by evaporating a little of the acid in a small porcelain saucer, or on a piece 
 of glass, and seeing if any residue be left. Pure acid should leave nothing ; 
 if the residue is of a brown colour, it indicates iron. If the acid is found 
 by these tests to be pure, then the specific gravity may be taken to ascertain 
 its strength. The following table will serve as a guide : — 
 
 of Spec. Grav. 
 ) in 100 parts. 
 
 Specific Gravity. 
 
 Muriatic A 
 
 100 
 
 1-2000 
 
 40-777 
 
 99 
 
 1-1982 
 
 40-369 
 
 98 
 
 1-1964 
 
 39-961 
 
 97 
 
 1-1946 
 
 39-554 
 
 96 
 
 1-1928 
 
 39-146 
 
 95 
 
 
 38-738 
 
 94 
 
 1-1893 
 
 38-330 
 
 93 
 
 
 37-923 
 
 92 
 
 1-1857 
 
 37-516 
 
 91 
 
 1-1846 
 
 37-108 
 
 90 
 
 1-1822 
 
 36-700 
 
 89 
 
 1-1802 
 
 36-292 
 
 88 
 
 1-1782 
 
 35-884 
 
 87 
 
 1-1762 
 
 35-476 
 
 86 
 
 1-1741 
 
 35-068 
 
 85 
 
 1-1721 
 
 34-660 
 
 84 
 
 1-1701 
 
 34-252 
 
 83 
 
 1-1681 
 
 33-845 
 
 82 
 
 1-1661 
 
 33-487 
 
 81 
 
 1-1641 
 
 33-029 
 
 80 
 
 1-1620 
 
 32-621 
 
 79 
 
 1-1599 
 
 32-213 
 
 78 
 
 1-1578 
 
 31-805 
 
 77 
 
 1-1557 
 
 31-398 
 
 76 
 
 1-1536 
 
 30-990 
 
 75 
 
 1-1515 
 
 30-582 
 
 74 
 
 1-1494 
 
 30-174 
 
 73 
 
 1-1473 
 
 29-767 
 
 72 
 
 1-1452 
 
 29-359 
 
 71 
 
 1-1431 
 
 28-951 
 
 70 
 
 1-1410 
 
 28-544 
 
 69 
 
 1-1389 
 
 28-136 
 
 68 
 
 1-1369 
 
 27-728 
 
 67.. 
 
 1-1349 
 
 
 66 
 
 1-1328 
 
 26-913 
 
 65 
 
 1 1308 
 
 26-505 
 
54 
 
 HYDROCHLORIC ACID. 
 
 of Spec. Gray. 
 ► in 100 parts. 
 
 Specific Gravity. 
 
 
 Muriatic Acid. 
 
 64 
 
 
 
 26-098 
 
 63 
 
 1-1267 
 
 
 25-690 
 
 62 
 
 ........1-1247 
 
 
 25-282 
 
 61 
 
 1-1226 
 
 
 24-874 
 
 60 
 
 1-1206 
 
 
 24-466 
 
 59.. 
 
 
 
 24-058 
 
 58 
 
 1-1164 
 
 
 23-650 
 
 57 
 
 1-1143 
 
 
 23-242 
 
 56 
 
 1-1123 
 
 
 22-834 
 
 55 
 
 1-1102 
 
 
 22-426 
 
 54 
 
 1-1082 
 
 
 22-019 
 
 53 
 
 1-1061 
 
 
 21-611 
 
 52 
 
 ........1-1041 
 
 
 21-203 
 
 51 
 
 1-1020 
 
 
 20-796 
 
 50 
 
 1-1000 
 
 
 20-388 
 
 49 
 
 1-0980 
 
 
 19-980 
 
 48 
 
 1-0960 
 
 
 19-572 
 
 47 
 
 1-0939.. 
 
 
 19-165 
 
 46 
 
 1-0919 
 
 
 18-757 
 
 45..... 
 
 1-0899.. 
 
 
 18-349 
 
 44 
 
 1-0879 
 
 
 17-.941 
 
 43 
 
 1-0859 
 
 
 17-534 
 
 42 
 
 1-0838 
 
 
 17-126 
 
 41 
 
 1-0818 
 
 
 16-718 
 
 40 
 
 1-0798 
 
 
 16-310 
 
 39 
 
 1-0778 
 
 
 15-902 
 
 38 
 
 1-0758 
 
 
 15-494 
 
 37 
 
 1-0738 
 
 
 15-087 
 
 36 
 
 1-0718 
 
 
 14-679 
 
 35 
 
 1-0697.. 
 
 
 14-271 
 
 34 
 
 1-0677 
 
 
 13-863 
 
 33 
 
 1-0657 
 
 
 13-456 
 
 32 
 
 1-0636 
 
 
 13-049 
 
 31 
 
 1-0617 
 
 
 12-641 
 
 30 
 
 1-0597 
 
 
 12-233 
 
 29 
 
 1-0577 
 
 
 11-825 
 
 28 
 
 1-0557 
 
 
 11-418 
 
 27 
 
 1-0537 
 
 
 11-010 
 
 26 
 
 1-0517 
 
 
 10-602 
 
 25 
 
 1-0497 
 
 
 10-194 
 
 24 
 
 1-0477 
 
 
 9-786 
 
 23 
 
 1-0457 
 
 
 9-379 
 
 22 
 
 ........1-0437 
 
 
 8-971 
 
 21 
 
 1-0417 
 
 
 8-563 
 
BLEACHING. 
 
 55 
 
 Acid of Spec. Grav. 
 1*20 in 100 parts. 
 
 Specific Gravity. 
 
 Muriatic A 
 
 19 
 
 1*0377 
 
 7-747 
 
 18 
 
 1-0357 
 
 7-340 
 
 17 
 
 1-0337 
 
 6-932 
 
 16 
 
 1-0318 
 
 6-524 
 
 15 
 
 1-0298 . 
 
 .6-116 
 
 14 
 
 1-0279 
 
 5-709 
 
 13 
 
 1-0259 
 
 5-301 
 
 12 
 
 1-0239 
 
 ......4-893 
 
 11 
 
 1-0220 
 
 4-486 
 
 10 
 
 a -0200 
 
 .4-078 
 
 9 
 
 1-0180 
 
 3-670 
 
 8 
 
 1-0160 
 
 3-262 
 
 7 
 
 1-0140 
 
 2-854 
 
 6 
 
 ....1-0120 
 
 2-447 
 
 5 
 
 1-0100 
 
 2-039 
 
 4 
 
 ....1-0080 
 
 1-931 
 
 3 
 
 1-0060 
 
 1-224 
 
 2 
 
 1-0040.. 
 
 0-816 
 
 1 
 
 1-0020 
 
 0-408 
 
 Chloride of Nitrogen. — Chlorine combines with nitrogen to form 
 NC1 3 , which is one of the most explosive compounds known. It is a 
 heavy liquid substance, and, from its dangerous properties, cannot be of 
 any use to the dyer. 
 
 Chlorine also combines with some of the other non-metallic elements, 
 such as phosphorus, sulphur, carbon, &c., and forms compounds, some of 
 which are interesting in a chemical point of view, but not in respect to 
 their practical use in the dye-house*. The chlorides of the metals, how- 
 ever, are some of them important, and will be described in course under 
 the metals. 
 
 The great use of chlorine in the dye-house is as a bleaching agent — 
 into the consideration of which we will now enter a little more in detail. 
 
 While treating of light (page 9), we had occasion to notice the neces- 
 sity of goods being of a pure white previous to being dyed any light shade ; 
 otherwise the natural yellow colour of the goods, whether cotton, silk, or 
 woollen, would interfere with the particular shade wanted. If, for examph > 
 the shade required be a light pink upon cotton, and if it be put upon cotton 
 unbleached, the resulting colour would not be a pink, but a shade inter- 
 mediate between a salmon and a brick colour, from the yellow ray reflected 
 from the unbleached cotton mixing with the red reflected from the dye. 
 We must, therefore, before dyeing a light pink upon cotton get rid of these 
 yellow rays, and this is effected by the process of bleaching. Hence, the 
 dyer must, of necessity, be also a bleacher. 
 
 Where and when the practice of bleaching cloth first began we have 
 no account ; but we may reasonably suppose that as soon as man became 
 
5(5 
 
 BLEACHING. 
 
 so far civilised as to manufacture clothing, that the constant exposure of 
 that clothing to the atmosphere, and occasional washing, would naturally 
 suggest the idea of bleaching. However, we know that bleaching is of 
 very ancient origin, mention being made of it in the oldest books extant. 
 What was the nature of the process practised in these early times is not 
 clear ; but from the earliest description to the close of last century, no other 
 process was known but alternate boiling, washing, and exposure to the 
 atmosphere, a process which required a number of months to complete; 
 but, since the application of chlorine to this purpose, an application which, 
 as the late Professor Graham observed, “ is one of the most valuable which 
 chemistry has presented to the arts,” the process is completed in a few 
 days ; nay, for the most of dyeing operations, in a few minutes. 
 
 As many are now unacquainted with the routine of the process of 
 bleaching previous to the introduction of chlorine, it may be worth while 
 to give a short description of it, to illustrate the advantages obtained from 
 the application of science to the arts. The first operation was that of 
 steeping, which was merely immersing the yarn in hot water or cold 
 alkaline leys. When water was used, the steeping lasted for three or four 
 days, but with alkaline leys forty-eight hours were sufficient ; the goods 
 were then washed, and boiled in an alkaline ley for four or five hours ; 
 washed and exposed on the grass for two or three weeks ; again boiled or 
 bucked , which is a technical term for boiling; washed and crofted , a techni- 
 cal term for exposing on the grass, as before. These alternate operations of 
 bucking, washing, and crofting, were generally repeated four or five times, 
 each time reducing the strength of the alkaline leys in which the bucking 
 was performed. 
 
 The next process was that of souring, which, till nearly the middle of 
 last century, consisted in steeping the goods for several weeks in soured 
 butter-milk. This process was much shortened by Dr. Home, who sug- 
 gested the use of sulphurie acid (vitriol) instead of milk; and twelve hours, 
 with a sour of this acid, were sufficient.* After the first souring, the 
 operations of boiling, washing, souring, and crofting were repeated in 
 regular rotation, until the cloth or yarn came to a good colour, and was 
 considered perfectly clear. A quantity of soap was generally used in the 
 last operations of boiling. The number of times these operations were 
 repeated varied according to the quality of the goods ; linen was seldom 
 finished in less than six months, and cotton goods varied from six weeks to 
 three months. The kind of weather hastened or retarded the operation. 
 
 Various opinions were advanced to explain the nature of the chemical 
 changes induced during these operations ; but such opinions could be only 
 hypothetical so long as the composition of the atmosphere and of water 
 were not known, two substances which acted a very prominent part in these 
 operations, nnd also while they were ignorant of the nature of the colouring 
 matter upon the goods, and its composition. We have already given the 
 composition of water and air, but the composition of the colouring matter 
 * Home On Bleaching. 
 
BLEACHING. 
 
 57 
 
 upon cotton, &c., has not as yet been very accurately ascertained. Its pro- 
 perties are neutral, and it is composed of hydrogen and carbon with oxygen ; 
 a portion of which is soluble in alkalies and water, and therefore taken off 
 by steeping and boiling. These colouring matters do not form a part of 
 the cotton, but mechanically adhere to it, so that substances may act upon 
 and decompose them without in the least destroying the cotton ; indeed, 
 from a number of experiments, cotton is found as strong when deprived 
 of these substances as before. 
 
 In boiling eotton yarn in water alone, or with an alkali, it loses con- 
 siderably in weight, different qualities of cotton varying in this respect ; 
 fine qualities -lose least. When the alkaline ley in which the cotton has 
 been boiled has acid added, there is a precipitate obtained of a light brown 
 colour, which being washed from the alkaline salt was found by Dr. 
 Schunck to contain 
 
 A colouring matter, easily soluble in alcohol. 
 
 A colouring matter, sparingly soluble in alcohol. 
 
 A waxy substance, termed cotton wax. 
 
 Manganic acid. 
 
 Pectic acid, and an albuminous matter. 
 
 The principal part was pectic acid, the ultimate analyses of each giving 
 carbon, oxygen, and hydrogen, but the absence of this does not lessen 
 the colour of the cotton much. From a number of experiments made to 
 ascertain the loss of weight by bleaching various qualities of cotton, the 
 average loss may be taken at 5 per cent, of the weight of the cotton. 
 
 In order to ascertain the chemical changes which take place when 
 goods are bleached in the air, M. Berthollet, finding that those seasons 
 when most dew was -deposited, were the most effective upon the colour, 
 examined the dew which condenses upon the grass, and found it to contain 
 a sufficient quantity of oxygen to destroy the colour of turnsole paper.* 
 What errors led to these results we do not know, for although dew 
 did contain oxygen, it would not give it acid properties to redden turn- 
 sole paper. Or whether M. Berthollet considered the bleaching property 
 of dew was owing to its having free oxygen, or to the supposed acid pro- 
 perty of oxygen, we do not know, not having seen the original details. 
 Could we suppose the formation of peroxide of hydrogen (page 39), the 
 effects would be easily explained. Ozone has probably something to do 
 with it (see Ozone). The theory of croft bleaching has been explained 
 variously as follows: — 
 
 1. The oxygen of the atmosphere combines with the colouring matter 
 of the cotton, forming a new substance capable of solution in water or 
 alkalies, and comes off by washing or boiling; or it combines with some of 
 the elements of the colouring matter, such as the carbon, forming carbonic 
 acid gas, which escapes into the air, or with the hydrogen, and forms 
 * Parke’s Chemical Essays. 
 
58 
 
 CHLOHINE AS A BLEACHING AGENT, 
 
 water ; those elements which are left form either colourless substances, or 
 substances soluble in the next operation. 
 
 2. The oxygen combines directly with the colouring matter, forming 
 a permanent and colourless oxide. This would add weight to bleached 
 cotton. 
 
 3. The water acts otherwise than being merely a solvent; that it, 
 or one of its elements, combines with the colouring substance producing 
 the effects noticed in the first proposition. Hence dew being pure and free 
 from any admixture which might retard this union, is better fitted for 
 bleaching; consequently in seasons when most dew is deposited, the bleach- 
 ing process will be accelerated. Which of these theories is the true one 
 we cannot say ; but we know that light facilitates the process of bleaching, 
 and this circumstance, we think, favours the supposition of the colouring 
 matter being decomposed. Other interesting theories might be advanced 
 from phenomena observed during the process of croft bleaching; and also 
 the part that boiling in alkali and the sours take in the operation. 
 
 The modern process of bleaching, and that which is now almost uni- 
 versally practised, is by means of chlorine. This substance, as has been 
 mentioned (page 49), was discovered by Scheele, who also described its 
 peculiar property of destroying vegetable colouring matters; but M. 
 Berthollet was the first who called the attention of the public to its value 
 as a bleaching agent, in 1785. About the time this chemist was prose- 
 cuting his inquiries into the nature of this substance, he was visited by the 
 celebrated James Watt, to whom Berthollet related the results of his 
 experiments upon bleaching, and from this circumstance the inventor of 
 the modern steam engine became also the introducer of the new process of 
 bleaching into this country. Some give this honour to Professor Copland 
 of Aberdeen ; but from the evidence we have seen, it belongs to Watt, 
 although the difference of time was little. 
 
 The introduction of chlorine, as a bleaching agent, like all other dis- 
 coveries which tend to overturn old practices, met with a host of opposition. 
 The most prominent objections offered were, that it destroyed the cloth, 
 did not give a permanent white, and that it killed the men who wrought 
 with it. These statements were not altogether groundless, but the force 
 with which they were urged hastened improvements and effected remedies. 
 The first method of using chlorine was by saturating cold water with the 
 gas, the water taking up about twice its volume of it. The goods were 
 put into this water, after which it was heated to set free the gas, in order that 
 it might act upon the colouring matter ; but, the goods being impaired by 
 this process, even when the greatest care was taken, suggested the diluting 
 of the chlorine water ; which diluted liquor was found to bleach equally 
 well, and the goods were preserved. The defect of the goods becoming 
 yellow after a few days, suggested alternate boiling with alkaline leys ; and 
 the difficulty arising from the workmen being unable to endure the effects 
 of inhaling the escaping gas, led to the discovery that alkalies not only 
 absorb a greater quantity of chlorine than water, but that they hold it with 
 
BLEACHING POWDER. 
 
 59 
 
 greater affinity, not allowing the gas to escape so readily into the atmo- 
 sphere, at the same time parting with it more regularly and effectively to 
 the goods. The alkalies used were soda and potash, and each bleaching- 
 work had its regular apparatus of retorts and carboys, or wooden 
 chests, for the purpose of making chloride of potash or soda. This 
 practice is still continued in some print-works, both in Scotland and 
 England, for particular fabrics or delicate operations, as it is considered 
 much safer and better adapted for certain purposes than the common 
 bleaching powder. In the year 1798, Mr. Tennant of Glasgow patented a 
 process for using a solution of lime for absorbing the chlorine instead of 
 potash and soda ; shortly after, the hydrate of lime (slaked lime) was sub- 
 stituted for lime-water, and this is the preparation now used for bleaching, 
 under the names of bleaching powder and chloride of lime. Other minor 
 improvements have been made regarding the quantity of chlorine absorbed 
 by the lime under certain conditions, which will be noticed afterwards. 
 
 Notwithstanding all these discoveries and applications, the real nature 
 of the decolouring agent was long unknown : it was prepared by digesting 
 together a mixture of common salt, peroxide of manganese, and sulphuric 
 acid. The decomposition was explained as follows : — The sulphuric acid 
 combined with the soda of the salt and set the muriatic acid which was in 
 union with the soda at liberty. The oxide of manganese gave off a part of 
 its oxygen, which combined with the free muriatic acid, and formed oxy- 
 genated muriatic acid, a name which was first applied to this new substance ; 
 but after being introduced into the arts, this name was considered too un- 
 wieldy for common use, and was therefore contracted into oxy-muriatic 
 acid. It was ultimately contracted, by the workmen into oxygen , and, not- 
 withstanding the discovery of Sir H. Davy, in 1811, that oxy -muriatic acid 
 was not common muriatic acid with more oxygen, but a simple body 
 which he called chlorine, the name oxygen was and is still given to 
 bleaching powder and all its preparations by old bleachers. This is a 
 serious evil to the workmen ; not practically, but for their own under- 
 standing; as it identifies chlorine with oxygen, a substance which effects 
 reactions in the operations of dyeing quite distinct from those with which 
 it is identified. We remember the difficulty and confusion we were in 
 on learning that it was the oxygen of the air that supported life, and that 
 it was the same oxygen which turned the green colour of the goods while in 
 the vat to blue when exposed to the atmosphere, and at the same time seeing 
 bleaching liquor, which was also termed oxygen, destroying blues, and 
 felt that we could not breathe air containing its gas but with the greatest 
 difficulty. To solve this puzzle, every chemical book we could find was 
 examined for remarks on oxygen ; but, to our mortification, not one of 
 these works alluded to its bleaching properties. We doubt not but many 
 others have been in the same dilemma. The following order will shew our 
 young chemical friends the ridiculous position in which dyers and bleachers 
 were placed by retaining such names : — 
 
60 
 
 BLEACHING POWDER. 
 
 “Glasgow, . 
 
 “Messrs. * * Will please send, at their earliest convenience, a 
 
 cask of their strongest oxygen, containing as near as possible 2 cwt., let 
 it be newly made and dry : the last was damp, so that in a few days it 
 became like as much clay, and lost the most of its strength. — Your atten- 
 tion will oblige yours,” &c., &c. 
 
 Such ignorance need not be now, from the many excellent works on 
 chemistry within easy reach of the working dyer. 
 
 We are informed that chemic is still a common name for bleaching 
 liquor in some print-works; and that there are many names for other sub- 
 stances equally unsuitable. We will give a table of these technical terms with 
 their proper designations in another part of the volume. In the meantime, 
 we state that there is no better name for the substance we have been 
 describing than bleaching powder , or, if in solution, bleaching liquor. 
 
 Bleaching powder is prepared by exposing the hydrate of lime (slaked 
 lime) to an atmosphere of chlorine gas till the lime ceases to absorb the 
 gas. In practice, it is found that when the lime is in combination with an 
 extra equivalent of water, it will absorb much more chlorine than when it 
 has just as much water as slakes it. The chlorine is passed slowly into 
 large vessels or chambers furnished with shelves, upon which the lime is 
 placed, which combines with the chlorine forming bleaching powder. It 
 is white and pulverulent, and has a hot, bitter, and astringent taste, and a 
 peculiar smell. 
 
 Some of the continental chemists first suggested that the chlorine was 
 not merely absorbed and retained by the lime, but that it combined with 
 it, and formed one or more definite compounds. This has led to a great 
 deal of research, but scarcely to any definite conclusions, as there are 
 various compounds of chlorine with oxygen which may be formed during 
 the preparation of bleaching powder, and which possess bleaching pro- 
 perties as well as the chlorine alone. The most general supposition is, that 
 hypochlorite of lime is formed, and that on this salt, and its decomposition, 
 depend the operations of bleaching. This opinion is well-founded and 
 may be taken as expressing the true composition of bleaching powder, 
 which is therefore to be regarded as a definite salt of lime and hypo- 
 chlorous acid, with chloride of calcium and hydrate of lime. 
 
 The theory of the action of chlorine, when brought into contact with 
 slaked lime, is as yet hypothetical. The following has been given as the 
 probable reaction. Part of the oxygen of the lime combines with the 
 chlorine and forms hypochlorous acid, which combines with part of the 
 lime and forms hypochlorite of lime, and the calcium left combines with a 
 portion of chlorine, forming chloride of calcium. If the whole of the lime 
 was taken up according to this theory, the powder formed would have in 
 100 parts — 
 
BLEACHING POWDER. 
 
 61 
 
 Hypochlorite of lime, • . . . . 49-31 
 
 Chloride of calcium, 38-28 
 
 Water, 12-41 
 
 100-00 
 
 but the result is never found anything approaching to this, seldom over 
 three-fourths of this. There are probably other reactions interesting to the 
 chemist, although not affecting the practical results. When bleaching 
 powder is put into cold water, there is always left a quantity of insoluble 
 matter, composed of carbonate and hydrate of lime and other impurities, 
 not taken into account in the above analysis. 
 
 The best bleaching powder of commerce seldom contains above thirty 
 per cent, of chlorine available in bleaching ; but there are few of the sub- 
 stances employed by the dyer or bleacher more liable to change ; indeed, 
 from its first formation there seems to be a constant chemical action going 
 on between the chlorine and the lime ; oxygen is disengaged, and chloride 
 of calcium formed, a substance which possesses no bleaching properties. 
 These changes may be much retarded by keeping the powder perfectly dry, 
 or by dissolving it in cold water, and keeping the solution excluded from 
 the air. Chloride of lime (bleaching powder) having in it so much chloride 
 of calcium, a deliquescent salt, which, when exposed to the air, becomes 
 moist, and the powder is thus rapidly changed, and allowing that the lime 
 previously contained two equivalents of water, these combine with the 
 chloride of calcium ; and place this salt in the best circumstances for 
 attracting more water from the air, thus hastening the destruction of the 
 remaining hypochloride of lime. We have seen good bleaching powder, 
 by keeping it in a damp place, reduced to a pasty state in a few weeks, 
 and its bleaching properties almost totally destroyed. 
 
 As chloride of lime loses its bleaching properties on standing exposed 
 and by several other circumstances, it is of the utmost consequence to the 
 consumer that he should have some means of determining its real value, 
 both for the sake of safety and accuracy in his processes, and its com- 
 mercial worth. We have seen bleaching powder, which did not contain 
 above ten per cent, of chlorine, charged and paid for at the same rate as 
 that which contained thirty per cent. ; but not having the means of testing 
 it previously, the quality was not discovered till the salt was in solution ; 
 indeed, we are not aware of any relative prices, according to the quality of 
 this article, although with a very little care and trifling expense the dyer 
 may know the value of the article he is about to purchase, and of course 
 only pay accordingly. The first method of determining the value of 
 bleaching powder was by sulphate of indigo, but the indigo solution alters 
 by keeping, and is therefore objectionable. “ Several exact methods,” says 
 the late Dr. Graham, in his Elements of Chemistry, “ of which that in which 
 sulphate of iron is used, appears to be entitled to preference. This method 
 is based upon the circumstance that the chlorine of chloride of lime converts 
 
62 
 
 BLEACHING POWDER. 
 
 a salt of the protoxide into a salt of the peroxide of iron. It is found by 
 experience that ten grains of chlorine are capable of peroxidising 78 grains of 
 crystallised sulphate of iron. In an experiment to determine the percent- 
 age of chlorine in a sample of bleaching powder, some good crystals of 
 protosulphate of iron (copperas) are to be pounded and dried by pressing 
 between folds of cloth; 78 grains are dissolved in about two ounces of 
 water acidulated by a few drops either of sulphuric or muriatic acid; then 
 50 grains of the chloride of lime to be examined, are dissolved in about two 
 ounces of water, by rubbing them together in a mortar, and the whole 
 poured into a vessel graduated into a hundred parts. The common alkali- 
 meter will do. This is a straight glass tube, or generally a very narrow 
 jar about f of an inch in width, and 14 inches high, mounted upon a 
 foot, as shewn in the accompanying figure, capable at least of containing 
 a thousand grains of water, and graduated into a hundred 
 parts. The jar containing the 50 grains of chloride of lime 
 is filled up to the highest graduation by the addition of 
 water, and the whole is well mixed. The clear part of this 
 solution is gradually poured into the solution of sulphate 
 of iron, till the latter is completely peroxidised. This is 
 known by means of red prussiate of potash, which gives a 
 blue precipitate with the protoxide, but not with the per- 
 oxide of iron. A white plate of porcelain or glass is 
 spotted over with small drops of the prussiate ; a drop of 
 iron solution is mixed with one of these after every 
 addition of chloride of lime ; and the additions continued 
 so long as the prussiate drops are coloured blue. They 
 may be coloured green, but that is of no moment. When 
 the iron is peroxidised, the number of graduations or mea- 
 sures of chloride of lime required to produce that effect is noted; the 
 quantity of chlorine in the 50 grains of bleaching powder is now known, 
 being ascertained by proportion. Thus, if it required 68 measures of the 
 bleaching solution, then, as 68 is to 10, so 100 is to 14-7, the chlorine in the 
 50 grains of powder ; this being multiplied by two, gives the percentage of 
 chlorine in the sample, which is 29*4.” We have found, in operating in 
 this way, a liability to lose a little chlorine as gas. This is obviated by 
 having the iron solution in a stoppered bottle, and upon every addition of 
 bleaching liquor to put in the stopper and shake the bottle. 
 
 Another process recommended by Gay Lussac, which combines sim- 
 plicity with accuracy, is now in general use with the manufacturers of 
 bleaching powder. A solution of arsenious acid is made in muriatic acid, 
 and diluted with water. On adding a solution of chloride of lime, the 
 muriatic acid takes the lime ; the chlorine decomposes the water, combining 
 with its hydrogen, while the oxygen unites with the arsenious acid, and 
 converts it into arsenic acid. When the arsenious solution is tinged with 
 sulphate of indigo, and bleaching liquor added, there is no change takes 
 place on the indigo until the whole arsenious acid is transformed into 
 
BLEACHING POWDER. 
 
 63 
 
 arsenic acid ; but the first drop after this discolours the indigo. The 
 correctness of this test is founded upon the knowledge of what proportion 
 of chlorine is necessary to oxidise the arsenious acid in the test solution. 
 Various proportions have been proposed as the standard strength of the 
 solution ; but it does not matter much what proportions are used, provided 
 the operator knows what proportion of chlorine is necessary to transform 
 it, and being careful always to have it the same. The best proportions for 
 general use are those that require the least calculation. The following 
 proportions we have found to do very well, and to be easily counted. Take 
 two ounces of arsenious acid (common arsenic of the shops), and dissolve it 
 by digestion for a few minutes at a boiling heat, in 24 ounces by measure 
 of pure muriatic acid, then add 46 ounces by measure of distilled water ; 
 but in case of any loss by evaporation during digestion, it is better to have 
 a vessel which contains up to a certain mark 70 ounces, and when the 
 acid solution is put into it, to fill up to the mark with water. This may be 
 bottled and put past as the standard test liquor. Every three ounces by 
 measure of it are equivalent to twenty-five grains of chlorine. When a 
 sample of bleaching powder is to be tried, two hundred grains are carefully 
 weighed and dissolved in the manner already described, in twice as much 
 water as will fill the alkalimeter, or any other vessel graduated into a 
 a hundred parts. Three ounces of the arsenious solution are measured 
 out and put into a glass jar or tumbler, and tinged with sulphate of indigo. 
 The alkalimeter is now filled with the bleaching liquor, which is added 
 slowly to the arsenious solution, stirring constantly, and watching every 
 drop that is added for the decolouring of the indigo. If the sample be so 
 poor in chlorine that one measure of the alkalimeter will not change the 
 colour of the indigo, it may be filled again, and the process continued till 
 the indigo is decoloured, and the whole number of graduations taken to 
 effect this carefully noted; the fewer the number of graduations required, 
 the richer the sample is in chlorine. Now, as every three ounces of the 
 test liquor contain arsenious acid equivalent to 25 grains of chlorine, if the 
 hundred measures effect the change of the arsenious into the arsenic acid, 
 the value of the sample is exactly 25 per cent. ; in other words, every four 
 graduations taken to effect this change indicate one per cent, of chlorine. 
 These equivalents were practically determined, and may differ a little from 
 the theoretical calculation by atomic numbers, but the difference does not 
 vary above half a per cent., and is not of much consequence in practice. 
 The following table will serve as a guide to those who may adopt our 
 proportions. 
 
 The following table includes almost the whole range of percentage of the 
 bleaching powder of commerce; but should the dyer meet with any not 
 included in the table, the percentage may be calculated as follows. As 
 the number of measures is to 100, so is 25 to the answer required. Say, 
 for example, the measure is 160 — then 160 : 100 :: 25 : 15*62. 
 
 Any of the two methods just described may be performed in a few 
 minutes ; and in a substance that is liable to such deterioration, it is surely 
 
64 
 
 BLEACHING POWDER. 
 
 Measures. 
 
 Per cent. 
 
 Measures. 
 
 Per cent. 
 
 Measures. 
 
 Per cent. 
 
 Measures. 
 
 Per cent 
 
 150 
 
 16*66 
 
 127 
 
 19*68 
 
 104 
 
 24*03 
 
 81 
 
 30*86 
 
 149 
 
 16*77 
 
 126 
 
 19*84 
 
 103 
 
 24*27 
 
 80 
 
 31*24 
 
 148 
 
 16*89 
 
 125 
 
 20*00 
 
 102 
 
 24*51 
 
 79 
 
 31*64 
 
 147 
 
 17*00 
 
 124 
 
 20*16 
 
 101 
 
 24*75 
 
 78 
 
 32*05 
 
 146 
 
 17*12 
 
 123 
 
 20*32 
 
 100 
 
 25*00 
 
 77 
 
 32*46 
 
 145 
 
 17*24 
 
 122 
 
 20*49 
 
 99 
 
 25*25 
 
 76 
 
 32*89 
 
 144 
 
 17*36 
 
 121 
 
 20*66 
 
 98 
 
 25*40 
 
 75 
 
 33*33 
 
 143 
 
 17*48 
 
 120 
 
 20*83 
 
 97 
 
 25*77 
 
 74 
 
 33*78 
 
 142 
 
 17*60 
 
 119 
 
 21*00 
 
 96 
 
 26*04 
 
 73 
 
 34*24 
 
 141 
 
 17*73 
 
 118 
 
 21*18 
 
 95 
 
 26*31 
 
 72 
 
 34*72 
 
 140 
 
 17*85 
 
 117 
 
 21*36 
 
 94 
 
 26*58 
 
 71 
 
 35*21 
 
 139 
 
 17*98 
 
 116 
 
 21*55 
 
 93 
 
 26*87 
 
 70 
 
 35*71 
 
 138 
 
 18*11 
 
 115 
 
 21*73 
 
 92 
 
 27*17 
 
 69 
 
 36*23 
 
 137 
 
 18*25 
 
 114 
 
 21*93 
 
 91 
 
 27*48 
 
 68 
 
 36*75 
 
 136 
 
 18*38 
 
 113 
 
 22*12 
 
 90 
 
 27*77 
 
 67 
 
 37*31 
 
 135 
 
 18*51 
 
 112 
 
 22*32 
 
 89 
 
 28*08 
 
 66 
 
 37*87 
 
 134 
 
 18*65 
 
 111 
 
 22*52 
 
 88 
 
 28*40 
 
 65 
 
 38*46 
 
 133 
 
 18*79 
 
 110 
 
 22*72 
 
 87 
 
 28*73 
 
 64 
 
 39*09 
 
 132 
 
 18*94 
 
 109 
 
 22*93 
 
 86 
 
 29*06 
 
 63 
 
 39*68 
 
 131 
 
 19*08 
 
 108 
 
 23*14 
 
 85 
 
 29*41 
 
 62 
 
 40*32 
 
 130 
 
 19*23 
 
 107 
 
 23*36 
 
 84 
 
 29*76 
 
 61 
 
 40*98 
 
 129 
 
 19*38 
 
 106 
 
 23*58 
 
 83 
 
 30*12 
 
 60 
 
 41*26 
 
 128 
 
 19*53 
 
 105 
 
 23*81 
 
 82 
 
 30*48 
 
 
 
 of importance that the purchaser should have some knowledge of the 
 quality of the article he is purchasing, and that the workmen know some- 
 thing of the strength of the substance they are working with. Might not 
 a certain price be fixed for a standard strength of bleaching powder, and 
 to rise and fall according to the percentage of chlorine which it contains, 
 in the same manner as practised with soda-ash ? It would at least save 
 much annoyance and the common complaint, “ that the last cask was not 
 so good as the former.” The adoption of some such plan, we are con- 
 fident, would be satisfactory to all parties. 
 
 To prepare chloride of lime for bleaching, an aqueous solution is 
 requisite. For this purpose a quantity is put into a large vessel filled with 
 water, well stirred, and allowed to settle ; this is termed the stock liquor. 
 There are no definite proportions for making up this vat : every bleacher 
 makes up his stock- vat to a certain strength, indicated by Twaddell’s hydro- 
 meter, a most fallacious test, as the chloride of calcium, and every other 
 matter which is soluble in water, although it has no bleaching properties, 
 affects the hydrometer. Care should be taken that this stock-vat be 
 protected from the air as much as possible, as the lime absorbs carbonic 
 acid, and the chlorine being set at liberty, occasions considerable loss. 
 This may be illustrated by putting a little of the solution upon a flat 
 plate, and allowing it to stand a few days, when it will be found to have 
 lost its bleaching power altogether. 
 
 The first operation in bleaching cloth is steeping it in a waste ley, or 
 
BLEACHING POWDER. 
 
 66 
 
 tepid water, for a number of hours, generally over night: this is termed the 
 fot steep : its object is to loosen the paste and dirt that may have adhered 
 to the cloth during its manufacture. This steep ought not to be hotter 
 than blood heat, otherwise, if oil be upon the cloth, it is not saponified, 
 neither is it so easily taken out after ; in all cases when oil is observed, it 
 ought to be taken out by rubbing with soft soap and cold water previous to 
 putting the cloth into the steep. The goods are thoroughly washed from this 
 steep in the dash wheel, but if a wheel is not convenient, they are tramped 
 in water, and then washed by rinsing them through water with the hands ; 
 they are then ready for the boiler. The boiling ley is made up by taking 
 strong caustic ley (see soda and potash), a quantity equal to about six 
 pounds weight of alkali to one hundred pounds weight of cloth, having 
 as much water in the boiler as will allow the goods sufficient play when 
 boiling; they ought to boil for three hours. When goods are for 
 light delicate colours, such as Prussian blues, the success of a bleach 
 for such colours depends much upon a good boil. The goods arO 
 well washed from the boil, and allowed to drain; the draining is facili- 
 tated by pouring hot water upon them ; they are then hanked up, 
 taking out all the twists, and laid into the bleaching liquor as loose as 
 possible. The vessels which contain this liquor are large, made either of 
 stone or wood, and are termed bleaching vats or troughs. To prepare this 
 liquor, these troughs are filled with water, and a quantity 
 of the stock liquor added until the required strength is 
 obtained, which is indicated by its action upon the sul- 
 phate of indigo, in what is termed the test-glass, a vessel 
 of this form. It is filled to the mark a with the sulphate 
 of indigo : this indigo is generally supplied by the manu- 
 facturers of the powder as test blue, the liquor is added 
 drop by drop until the colour of the indigo is destroyed ; 
 the quantity taken to effect this is denoted by the gradua- 
 tions above; the weaker the liquor, the greater the 
 number of graduations required; each of these graduations 
 is termed its degree ; two degrees are considered a fair strength for light 
 goods, but for heavy fabrics it may be made stronger ; they are allowed to 
 steep in this for several hours, varying according to the nature of the 
 goods. The objections we previously stated to the use of sulphate of 
 indigo as a test in the former case are equally applicable here. We have 
 found this test to be very uncertain. A much better method has been 
 adopted by the late Mr. Walter Crum, a description of which was read by 
 him to the Glasgow Philosophical Society, and published in the Report of 
 that Society for 1841. We quote the following important paragraphs of 
 the paper, reserving the old notations : — 
 
 “ Chlorimetry requires to be practised by the bleacher for two pur- 
 poses — First, he has to learn the commercial value of the bleaching 
 powder which he purchases; and with that view he can scarcely desire 
 anything better than the method either by arsenious acid or green 
 
 E 
 
06 
 
 BLEACHING POWDER. 
 
 copperas. But tlie more important, because the hourly testing of his 
 bleaching liquor, and that on which the safety of his goods depends, is 
 the ascertaining the strength of the weak solutions in which the goods 
 have to be immersed. If the solution is too strong, the fabric is apt 
 to be injured. If too weak, parts of the goods remain brown, and the 
 operation must be repeated. The range within which cotton is safe in 
 this process is not very wide. A solution standing 1° on Twaddell’s 
 hydrometer (spec. grav. 1*005) is not more than safe for such goods, 
 while that of half a degree is scarcely sufficient for the first operation 
 of stout cloth, unless it is packed more loosely than usual. When the 
 vessel is first set with fresh solution of bleaching powder, there is little 
 difficulty, if the character of the powder be known ; but when the goods 
 are retired from the steeping vessels, they leave a portion of bleaching 
 liquor behind unexhausted, which must be taken into account in restoring 
 the liquor to the requisite strength for the next parcel. The chlorimeter 
 must, therefore, be applied every time that fresh goods are put into the 
 liquid. It must, consequently, be intrusted to persons who may not be 
 expert either in figures or in chemical manipulation. Hence all the 
 processes I have described are too delicate and tedious. 
 
 “ I introduced another into our establishment some years ago, which 
 has been in regular use ever since, and by which the testing is performed 
 in an instant. It depends on the depth of colour of the peracetate of 
 iron. A solution is formed of proto-chloride of iron, by dissolving cast- 
 iron turnings in muriatic acid of half the usual strength. To ensure 
 perfect saturation, a large excess of iron is kept for some time in contact 
 with the solution at the heat of boiling water. One measure of this 
 solution, at 40° Twaddell (spec. grav. 1*200), is mixed with one of acetic 
 acid, such as Turnbull and Co. of Glasgow sell at 8s. a gallon. That 
 forms the proof solution. If mixed with six or eight parts of water it is 
 quite colourless, but chloride of lime occasions with it the production of 
 peracetate of iron, which has a peculiarly intense red colour. 
 
 “ A set of phials is procured, 12 in number, all of the same diameter. 
 A quantity of the proof solution, equal to one-ninth of their capacity, is 
 put into each, and then they are filled up with bleaching liquor of various 
 strengths, the first at one-twelfth of a degree of Twaddell, the second, 
 two -twelfths, the third, three-twelfths, and so on up to twelve-twelfths, 
 or 1 degree. They are then well corked up, and ranged together, two and 
 two, in a piece of wood, in holes drilled to suit them. We have thus a 
 series of phials shewing the shades of colour which those various solutions 
 are capable of producing. To ascertain the strength of an unknown and 
 partially exhausted bleaching liquor, the proof solution of iron is put into 
 a phial similar to those in the instrument, up to a certain mark, one-ninth 
 of the whole. The phial is then filled up with the unknown bleaching 
 liquor, shaken, and placed beside that one in the instrument which most 
 resembles it. The number of that phial is its strength in 12ths of a degree 
 of the hydrometer ; and by inspecting the following table, we find at once 
 
BLEACHING POWDER. 
 
 67 
 
 how much of a solution of bleaching powder, which is always kept in 
 stock, at a uniform strength of 6 degrees, is necessary to raise the whole 
 of the liquor in the steeping vessel to the desired strength. 
 
 “The instrument is formed of long 2 ounce phials cast in a mould; 
 those of blown glass not being 
 of uniform diameter. The 
 outside, which alone is rough, 
 is polished by grinding, and 
 in this state they can easily be 
 procured at 4s. 6d. a dozen. 
 
 They are placed two and two, 
 so that the bottle containing the liquid to be examined may be set by 
 the side of any one in the series, and the colour compared by looking 
 through the liquid upon a broad piece of white paper stretched upon a 
 board behind the instrument. The above figure represents the instrument 
 fitted with tubes, which serve equally well. 
 
 “ To explain the table it is necessary to state that the steeping vessels 
 we employ contain, at the proper height for receiving goods, 1440 gallons, 
 or 288 measures of 5 gallons each, — a measure being the quantity easily 
 carried at a time. In the following table, 0 represents water, and the 
 numbers 1, 2, 3, &c., are the strength of the liquor already in the vessel 
 in 12ths of a degree of Twaddell, as ascertained by the chlorimeter. If 
 the vessel has to be set anew, we see by the first table that 32 measures of 
 liquor at 6° must be added to (256 measures of) water to produce 288 
 measures of liquor at eight-twelfths of a degree. But if the liquor already 
 in the vessel is found by the chlorimeter to produce a colour equal to the 
 second phial, then 24 measures only are necessary, and so on. 
 
 To stand T \° 
 
 
 To stand T e T ° 
 
 0 requires 32 measures. 
 
 0 
 
 requires 
 
 24 measures. 
 
 1 „ 
 
 28 
 
 1 
 
 
 20 
 
 2 „ 
 
 24 „ 
 
 2 
 
 
 16 
 
 3 „ 
 
 20 
 
 3 
 
 
 12 
 
 4 „ 
 
 16 „ 
 
 4 
 
 5’ 
 
 8 
 
 5 „ 
 
 12 „ 
 
 5 
 
 JJ 
 
 4 
 
 6 „ 
 
 8 
 
 
 
 
 7 „ 
 
 4 „ 
 
 
 
 
 To stand T ^° 
 
 
 To stand vj° 
 
 0 requires 
 
 16 measures. 
 
 0 
 
 requires 
 
 12 measures. 
 
 1 „ 
 
 12 
 
 1 
 
 
 8 
 
 2 „ 
 
 8 
 
 2 
 
 n 
 
 4 
 
 3 „ 
 
 4 
 
 
 
 
68 
 
 BLEACHING POWDER. 
 
 11 Let us see what takes place on mixing chloride of lime with proto- 
 muriate of iron. On the old view of the constitution of bleaching powder 
 — that it is a combination of chlorine and lime, we have — 
 
 3 (CaO, Cl) 
 6 FeCl 
 
 t 3 CaCl 
 
 becoming < 2 Fe 2 Cl 3 
 I Fe 2 0 3 
 
 the peroxide of iron forming peracetate with the acetic acid which is 
 present. Or, supposing with Balard that when two atoms of chlorine 
 unite with two atoms of lime, the product is CaCl-f-CaO, CIO, we have 
 this formula — 
 
 3 CaCl ) ( 6 CaCl 
 
 3 (CaO, CIO) > becoming ) 4 Fe 2 Cl 3 
 12 FeCl j ( 2 Fe 2 0 3 
 
 “ Here one-third only of the iron goes to form the deep coloured per- 
 acetate, while the whole might be employed for that purpose by using 
 protoacetate instead of protochloride. The latter, however, is preferred, 
 from the greater tendency of the acetate to attract oxygen from the air, 
 and consequently the greater difficulty of preserving it. Even with the 
 chloride it is best to give out small quantities at a time, preserving the 
 stock in well closed bottles.” 
 
 From this description it will be seen that the method recommended 
 by Mr. Crum may be adopted for testing the percentage of the powder, 
 as well as the strength of the liquors. However, we prefer the arsenious 
 acid process for strong solutions. 
 
 To return to the bleaching process. The goods being allowed to 
 steep in the bleaching liquor for some hours, they are lifted and washed, 
 after which, if they are thick stout goods, they are put into a sour for 
 a little, then washed, and again put through the same operations of boil- 
 ing, liquoring, and souring as before; but for all common fabrics, we have 
 found it the best practice to sweeten the goods from the liquor, building 
 the goods on a drainer and pouring water upon them till the water ceases 
 to taste of liquor as it comes from them, hank them anew, and put 
 them back into a new liquor of the same strength for a few hours, wash 
 them from this, and allow them to steep for an hour in strong sour of 
 vitriol and water, about pint of brown acid to four gallons of water. 
 Hydrochloric or muriatic acid may be used instead of vitriol. 
 
 There is perhaps no single branch connected with the art of dyeing 
 upon which there is greater difference of opinion than bleaching. Every 
 one has some peculiarity of his own ; but, when the peculiarities are all 
 compared, the difference in general is only nominal. One thing may be 
 noticed, namely, the necessity of washing the goods well from the liquor 
 before souring with vitriol, as any lime remaining upon the cloth 
 will be formed into an insoluble sulphate, and resist the dye. This, 
 however, is avoided by using muriatic acid. Some maintain that the 
 
BLEACHING POWDER. 
 
 69 
 
 presence of sulphate of lime is of no consequence; in our opinion, it 
 depends wholly upon the colour which is to be dyed on the cloth. We 
 have found that light pinks, light greens, light lavenders, and sometimes 
 light blues, when not washed well from the liquor, were often full of 
 white or lighter coloured spots, which we ascribed to that cause, although 
 there are white spots often occurring both on yarn and cloth from other 
 causes; but for dark shades we found no difference, and for colours to be 
 dyed with the bichromate of potash (chrome), such as yellows, ambers, 
 and orange, we seldom gave them any sour, only washed from the first 
 liquor, and then dyed. In souring fine piece goods with vitriol in a vessel 
 lined with lead, there was experienced for a long time a constant occur- 
 rence of small holes in the goods. On changing the vessel for a wooden 
 one, this evil entirely disappeared. The cause of the holes we could not 
 determine. 
 
 Cotton, in the hank (yarn), when it is to be finished white, goes 
 through the same process as cloth, with the exception of the rot steep; 
 but for dyeing a quicker operation is adopted. All cotton yarn must be 
 boiled in water for three or four hours previous to being dyed, whether 
 requiring to be bleached or not. Every lot of ten pounds weight, con- 
 stituting what is termed a bundle, is divided into six equal numbers of 
 spindles , and hung upon wooden pins about three feet long and two inches 
 thick ; this is termed sticking. 
 
 The stock-liquor for bleaching is generally prepared in a cask con- 
 taining about 120 gallons of water; to this is added about 20 lbs. of good 
 bleaching powder, stirred, and allowed to settle. A small tub of a size in 
 which a bundle is wrought freely, termed a ten pound tub, is filled nearly 
 two-thirds full with boiling water, and a bucket or pailful (about four 
 gallons) of the stock liquor added. The bundle is now let down as 
 quickly as possible, and turned over for about ten minutes, after which it 
 is put through a second tub of the same size, with water made a little sour 
 by adding about an imperial gill of strong vitriol or half a pint muriatic 
 acid. It is wrought in this for about five minutes. Being then well 
 washed, it is ready to be dyed almost any light shade. By this method 
 two men can bleach and wash two hundred pounds weight of yarn in about 
 three hours, a quantity which, by the other process of boiling, steeping, 
 and souring, would have occupied two days. 
 
 Having detailed the present method of bleaching cotton goods for 
 dyeing, we may say a little upon the chemical nature of these processes. 
 Previous to the discovery of the elementary nature of chlorine, when that 
 substance was considered a compound of muriatic acid and oxygen, it was 
 thought that the acid parted with its oxygen, and that this constituent 
 bleached the goods in the same way as atmospheric air was thought to do 
 in croft bleaching, but more rapidly. When the true nature of chlorine 
 was discovered, the theory was somewhat changed; finding, as was then 
 supposed, that chlorine did not bleach except water was present, it was 
 considered that the chlorine united with the hydrogen of the water form- 
 
70 
 
 BLEACHING POWDER. 
 
 ing muriatic acid, and that the liberated oxygen was still the bleaching 
 agent. 
 
 This theory is still maintained and supported by various analogies. 
 We quote the following from Gregory and Liebig’s edition of Turner's 
 Chemistry : — “ One of the most important properties of chlorine is its 
 bleaching power. All animal and vegetable colours are speedily removed 
 by chlorine, and when the colour is once destroyed, it can never be 
 restored. Davy proved that chlorine cannot bleach except water be pre- 
 sent; thus dry litmus paper suffers no change in dry chlorine, but when 
 water is admitted, the colour speedily disappears. It is well known, also, 
 that hydrochloric acid (muriatic acid) is always generated when chlorine 
 bleaches. From these facts it is inferred that water is decomposed during 
 the process, that its hydrogen unites with chlorine, and that decomposition 
 of the colouring matter is occasioned by the oxygen liberated. The 
 bleaching property of binoxide of hydrogen, and of chromic, and per- 
 manganic acids, of which oxygen is certainly the decolouring principle, 
 leaves little doubt of the accuracy of the foregoing explanation.” 
 
 Another theory has been advanced, and equally, if not more tenable, 
 by which the chlorine is supposed to act directly upon the colouring 
 matter. The following is from Sir Eobert Kane’s Treatise on Chemistry: 
 — “ Formerly it was considered that water was necessary for this bleaching, 
 and that the chlorine combined with the hydrogen, while the oxygen of 
 the water being thus thrown upon the organic substance, oxidised it, and 
 formed a new body, which was colourless. 1 have shewn, however, that, 
 this is not the case, but that the chlorine enters into the constitution of the 
 new substance formed, sometimes replacing hydrogen, at others simply 
 combining with the coloured body, and in some, the reaction being so 
 complete, that its immediate stages cannot be completely traced.” 
 
 This theory is also supported by several analogies, such as the action 
 of chlorine upon indigo already noticed ; but which of the changes 
 alluded to by Sir Eobert Kane takes place during the bleaching of cotton, 
 is not yet known. Chloride of lime, says the same author, does not 
 bleach except an acid be present to combine with the lime, and set the 
 chlorine at liberty; but this is only conditional. It is true, that if blue 
 litmus paper be put into a solution of newly dissolved chloride of lime, 
 it is not bleached; but if the solution be allowed to remain in contact 
 with the air for an hour or two, the lime combines with the carbonic acid 
 of the atmosphere ; and if the blue litmus paper be put into this solution, 
 it is instantly bleached by the liberated chlorine. Cotton that has not 
 been boiled in alkalies is acted upon as the litmus paper in both cases; 
 but if the cotton has received a good alkaline boil, and is well washed, 
 the bleaching process goes on, although the bleaching powder be newly 
 dissolved. This shews that the alkaline leys effect a change upon the 
 colouring matter. The nature of this change we are not as yet prepared 
 to state: several opinions have been given, but they are hypothetical, and 
 some of them are not borne out by practice. The theory of the forma- 
 
OZONE. 
 
 71 
 
 tion during bleaching of a colourless chloride, or oxide upon the fabric, 
 is not at all admissible, at least as regards cotton. According to this 
 theory, goods being bleached by having formed upon them a new com- 
 pound would become heavier, whereas practice shews that the operation 
 of bleaching causes the goods to lose in weight. Ozone is supposed by 
 some to play an important part in the relations of bleaching cotton. 
 
 It is known in practice, that whenever the cloth is put into the 
 bleaching liquor, there are acids formed, the principal of which is the 
 hydrochloric; but whether it is from the chlorine combining with the 
 hydrogen of the water, or the colouring matter of the goods, we cannot 
 say, the latter we think most probable. Our opinion is, that the chlorine 
 combines with the hydrogen of the colouring matter; and according to a 
 law we have several times alluded to, the remaining elements of the 
 colouring matter form a new substance, which is soluble, and thus the 
 whole colouring matter is taken off the cloth. In vats, where several 
 hundred pounds weight of cotton have been bleached before changing 
 the liquor, there is evidence of more substances remaining than merely a 
 solution of chloride of calcium ; but what these are have not, so far as we 
 know, been examined. 
 
 The effects of light in the operation of bleaching also favours this 
 hypothesis, for we know that exposure to the sun facilitates the process 
 very much. This circumstance, however, tells in favour of the theory 
 that the oxygen is the bleaching agent, as well as in favour of the theory 
 which makes the chlorine the bleaching agent. There is this difficulty, 
 however, which must not be overlooked, namely, that if a solution con- 
 taining chlorine is exposed to the light, there is a decomposition of the 
 water; for the chlorine combines with the hydrogen, and liberates the 
 oxygen. The oxygen, by this theory, requires to combine with the hydro- 
 gen of the colouring matter to form water — a series of affinities or reactions 
 which we cannot conceive — for if the affinity of the chlorine be stronger 
 for the hydrogen of the water than it is for the oxygen, it would take the 
 hydrogen from the colouring matter in preference, seeing that oxygen, 
 which by this theory has the weaker power, decomposes it to form water 
 again — a series of reactions altogether irreconcilable with one another. 
 
 Such is a brief outline of the processes of bleaching cotton goods for 
 dyeing, as practised in most dyeworks at the present day. Woollen and 
 silk are bleached by exposing them after being boiled or scoured to the 
 vapour of sulphurous acid, which process will be noticed under sulphur ; 
 but they are not thus bleached for dyeing. 
 
 Ozone. — It has long been known that when working with an electric 
 machine for some time, there was produced a peculiar smell. The same 
 kind of smell is often felt during a thunderstorm, when the lightning is 
 near giving, to the popular notion, the idea of brimstone. This smell is 
 due to the action of the electric discharges on the oxygen of the air. If 
 a little phosphorus be placed in a large bottle having a little water at 
 
72 
 
 SULPHUR. 
 
 bottom, and corked, the same smell is produced, and the air in bottle is 
 found to possess peculiar properties, somewhat like chlorine. It has 
 bleaching properties, decolours sulphate of indigo; it attacks mercury, 
 and liberates iodine from iodide of potassium; indeed, this substance is 
 employed for detecting the presence of ozone. These reactions were 
 first found out by Professor Schonbein, who considered it to be a distinct 
 substance, either elementary or compound, and called it Ozone, from a 
 Greek word, to smell. Much attention has been given to this substance 
 by different chemists, and the result of the inquiry is that ozone is oxygen 
 in an alio tropic state — that is, existing in a different state. It is found that 
 certain elements, by the action of different forces, may be changed in their 
 physical properties, such as colour, specific gravity, transparency, &c., 
 although still remaining an element. An excellent example of this is the 
 element carbon, existing as charcoal, graphite, and the diamond. Other 
 elements, as chlorine, hydrogen, &c., exist in different conditions. Ozone 
 is found to be oxygen in a condensed state, or rather oxygen combined 
 with oxygen. If pure dry oxygen gas be submitted to the silent discharge 
 of an electric current, it contracts in volume. If after this contraction it 
 be brought into contact with iodide of potassium, the iodide is decom- 
 posed by taking up oxygen, and the original bulk of gas is not altered. 
 On examining the solution of iodide, it is found that the amount of de- 
 composition effected corresponds with the amount of oxygen which has 
 suffered condensation. These results shew that three volumes of oxygen 
 have been condensed into two volumes by the electric current, and 
 consequently ozone is one and a-half times heavier than oxygen. Ozone is 
 produced in many operations, especially during combustion of bodies con- 
 taining hydrogen. Its great tendency to throw off one of its equivalents, 
 and to pass into ordinary oxygen, gives it great chemical energy in oxidising 
 bodies, and no doubt causes many important changes in nature not yet 
 investigated. If there were an easy method of forming ozone, it would be 
 found invaluable in many of the arts; and, judging from past experience, 
 we have no cause for despair. We will have occasion to refer to other 
 bodies having different conditions when speaking of isomerism. 
 
 Sulphur (S. 32). 
 
 Sulphur has been known from the earliest ages. It is found in large 
 quantities, uncombined, in the neighbourhood of volcanoes; and is also 
 extensively diffused through Nature in combination, especially with metals. 
 It is obtained in great abundance by roasting the sulphurets of iron, lead, 
 copper, and zinc. 
 
 Sulphur is a hard, brittle substance, of a greenish-yellow colour. It 
 is not soluble in water, and is not changed by exposure to the air. 
 When heated to a high temperature it volatilises, and deposits in the 
 fine powder well known as the flowers of sulphur . If heated in a close 
 
SULPHUR. 
 
 73 
 
 vessel, say a glass flask, to 218° Fall., it melts and becomes liquid as 
 water, but by increasing the heat it undergoes some curious changes; 
 at 340° it begins to get thick, and assumes a reddish colour ; and if the 
 heat be continued, it becomes so thick that it will not pour from the 
 vessel. At 482° it begins to become thinner, and continues thinning 
 until it boils at 750 °. When suddenly cooled from its most fluid state, 
 which is about 224° Fah., by throwing it into cold water, it becomes 
 instantly brittle ; but if cooled in the same manner, when thick (about 
 400°), it remains quite soft, and may be drawn into threads. If 
 heated in the open air to about 300 ° it takes fire, and burns with 
 a pale blue flame, and gives off most suffocating fumes of sulphurous 
 acid gas. 
 
 Sulphur combines with oxygen in several proportions, forming acids 
 of considerable importance in the arts. These are — 
 
 Sulphurous acid, H 2 SO 3 , . . . S0 2 Anhydrous. 
 
 Sulphuric acid, H 2 S0 4 , .... S0 3 Anhydrous. 
 
 Hyposulphurous acid, .... H 2 S 2 0 2 . 
 
 Hyposulphuric acid, .... H 2 S 2 0 3 . 
 
 Sulphurous Acid is a gaseous substance, and is always produced 
 when sulphur is burned in the air, or in oxygen. It may be prepared also 
 from the compounds of sulphur. If sulphuric acid be heated in contact 
 with metallic copper, or charcoal, sulphurous acid is given off. We 
 have — 
 
 2 S0 4 H 2 and Cu = S0 4 Cu S0 2 + 2 H 2 0. 
 
 If charcoal be used instead of copper in this experiment, carbonic acid gas 
 is also liberated. It may also be prepared by heating together three parts 
 flowers of sulphur and four parts black oxide of manganese, in a similar 
 apparatus to that described for the preparation of oxygen from manganese. 
 
 This gaseous acid, as has been stated, is much used in bleaching 
 animal substances, as silk and woollen; and also some vegetable sub- 
 stances, as straw. For these operations the gas is procured by merely 
 burning the sulphur in the air. The articles to be bleached are put into 
 a chamber or box, made as tight as possible, in which is placed a small 
 pan of sulphur, which is kindled by putting into it a piece of red-hot 
 iron. The chamber is then closed, and the articles, damp and well spread 
 out, are thus exposed to the sulphurous fumes. The gas is absorbed in 
 the first place by the water on the goods, and is thus brought into imme- 
 diate contact, and enabled to combine with the fabric. Goods bleached 
 by this gas are increased in weight, shewing that a combination has taken 
 place : they are not permanently white, the compound formed is decom- 
 posed ; indeed, the gas gradually escapes, and by immersing the goods in 
 a stronger acid, the white is destroyed. This may be beautifully illustrated 
 by exposing a red rose to the fumes of sulphurous acid gas : it is bleached 
 white, but by putting it into a sour (vitriol and water), the red colour is 
 restored. This shews the distinctive characters of this gas and chlorino 
 
74 
 
 SULPHUR. 
 
 as bleaching agents. Some bleachers of woollen pass the goods through a 
 solution of sulphurous acid in water, instead of stoving them. Bleaching 
 by this gas is not done with goods that are to be dyed. 
 
 Sulphurous acid passes readily into sulphuric acid by absorbing more 
 oxygen. In newly distilled water, or water having no air or oxygen dis- 
 solved in it, sulphurous gas may be kept a long time if well corked up, 
 but without these precautions it very soon combines with the oxygen dis- 
 solved in the water. If a quantity of peroxide of iron is put into a solution 
 of this gas, it passes into the state of sulphuric acid and protoxide of iron. 
 The formula is — 
 
 Fe 2 0 3 + S0 2 H 2 0 = S0 4 Fe + Fe0H 2 0. 
 
 Sulphuric Acid is one of the most important of the compounds of 
 sulphur; it is not produced by the direct action of its elements, but gene- 
 rally from the oxidation of sulphurous acid. We mentioned when treating 
 of nitrogen (page 41), that the binoxide of nitrogen on coming into con- 
 tact with the air combines with more oxygen, and is converted into the 
 peroxide or tretoxide of nitrogen ; and that this compound readily yields 
 its oxygen again to other bodies which have a strong attraction for it. If 
 sulphurous acid is brought into contact with peroxide of nitrogen in the 
 presence of water, a decomposition takes place, and there is formed sul- 
 phuric acid and nitrous acid, which may be represented by the formula — 
 
 S0 2 2 N0 3 H 2 = so 4 h 2 n 2 o 4 . 
 
 The manufacture of vitriol on the large scale is conducted, with slight 
 modifications, according to the fancy or experience of the manufacturer, 
 as follows, supposing that brimstone is the substance used : — A row of 
 brick-built chambers, about 2£ feet wide, 5 feet long, and 3J feet high, 
 arched over with a hole in roof leading into a flue running along the top — 
 the front being left open for a cast-iron door and for charging. A cast- 
 iron plate the whole length and breadth of the chamber or burner, with a 
 flange of inches, forms the bottom of each; this is built in about two bricks 
 above the floor, to allow a current of air to pass under. On starting, the 
 burner-plate, as it is called, is heated sufficient to kindle the sulphur, but 
 afterwards this is not necessary. Fifty pounds of brimstone is thrown 
 upon this plate, and along with it is put in an iron pot containing 5 lbs. 
 of nitrate of soda, with which is mixed 7 lbs. of brown vitriol ; the door 
 in front is then closed, leaving a small space for the admission of air. 
 The sulphur is kindled by the heat of the plate, and the fumes are 
 carried off by the flue on the top leading into large lead chambers. The 
 heat produces decomposition of the nitrate of soda and vitriol in the iron 
 pot, forming sulphate of soda; and the nitric acid is evolved and passes 
 off with the sulphurous gas to perform the actions and reactions in the 
 chambers. Small jets of steam are blown into the chambers at certain 
 intervals. These chambers are generally in sets of three, joined to- 
 
SULPHUR. 
 
 75 
 
 getlier by a small lead tunnel. In one work we know the first two of the 
 set are 80 feet by 20 wide and 18 high, the third stands across the end of 
 these two, and measures 42 by 20 by 18 feet. The real action and reaction 
 that takes place within the chambers between the sulphurous and nitrous 
 acids and steam are yet only hypothetically defined, and various ingenious 
 theories have been proposed, all having certain weak points in them. Fol- 
 lowing the ordinary explanation : — In the first place, as already stated, the 
 nitric acid evolved from the soda salt, is reduced by the sulphurous acid 
 liberating dioxide of nitrogen, which takes oxygen from the air it meet3 
 with in the chamber, forming with it compounds that are again decom- 
 posed, giving up their oxygen to the sulphurous acid — these combinations 
 and decompositions go on during their whole passage through the cham- 
 bers until all the sulphurous acid is converted into sulphuric acid or vitriol. 
 
 From the formula given above, it will be seen that one equivalent of 
 nitric acid liberated from the nitrate of soda gives up three equivalents 
 of oxygen to convert three equivalents of sulphurous acid into sulphuric 
 acid. There will thus be required, according to theory, about 2 lbs. of 
 nitrate of soda for every pound of sulphur ; but as we have stated, in prac- 
 tice, only 10 lbs. of nitrate of soda are used for 100 lbs. of sulphur, the oxy- 
 gen that is required further is taken from the air present in the chambers by 
 the reactions of the nitrous compounds just referred to ; hence the necessity 
 of chambers of large capacity to allow of sufficient air to supply oxygen 
 and time for the reactions to take place during their passage through the 
 chambers. The gases leaving the chambers to the chimney are per or 
 tretoxide of nitrogen, a little oxygen, the nitrogen of the air, and acid 
 vapour. Some manufacturers cause these to pass up through towers filled 
 with coke, placed between the chambers and chimney, down which is 
 caused to percolate strong vitriol, which possess the property of absorbing 
 the peroxide of nitrogen, and is led into the first chamber where the acid 
 is diluted, and it thus gives off the peroxide to do its work over again, 
 and thus save much nitrate of soda. 
 
 The vitriol found in the chamber falls as a heavy dew, and collects in 
 what may be termed the saucer of the chamber — the chambers being made 
 like a large dish, placed mouth down in a saucer. Small trays are placed 
 in different parts of the chambers, with pipes leading outside, through which 
 acid drops, and is caught and tested from time to time, care being taken 
 not to let it come under 90° Twad., or above 120° Twad. ; hence peroxide 
 of nitrogen is absorbed. The vitriol is drawn off by lead syphons, and 
 led to lead pans placed over a fire, and there evaporated until the acid 
 reaches 144° Twad., which is brown acid. If it is to be further concen- 
 trated, this is done in platinum or glass vessels, until its gravity rises to 
 168° Twad. — the ordinary strength of concentrated vitriol. It can be con- 
 centrated to 1G9£° Twad. ; but to do so requires extra time and care, and is 
 only done for special purposes. 
 
 The whole of the operation of making sulphuric acid may be shewn, 
 for illustration, by the following simple apparatus : — 
 
76 
 
 SULPHUR. 
 
 Generate sulphurous acid in one bottle (B), and peroxide of nitrogen in 
 another (C), and cause the two gases to meet in a third bottle (A), having 
 a little water at bottom; the formation of sulphuric acid will go on as 
 described, and be found in the water of the condensing vessel (A) after 
 the operation; or instead of water at bottom of (A), a jet of steam from 
 another flask may be led into it. 
 
 A great quantity of sulphuric acid is made by burning iron pyrites, 
 a native compound of iron and sulphur, FeS 2 . This mineral often con- 
 tains arsenic, which volatilises with the sulphurous acid and passes into 
 the acid-chamber; and therefore the vitriol made from this source con- 
 tains arsenic as an impurity. 
 
 Recently the principal source of pyrites is Spain. It is brought to 
 this country in large quantities, as much for the copper it contains as the 
 sulphur ; although, but for the acid makers burning out the sulphur, the 
 quantity of copper it contains would not pay to extract. The average 
 composition of the ore is shewn thus in 100 parts — 
 
 Sulphur, 
 
 
 ♦ 
 
 
 
 . 46-00 
 
 Iron, 
 
 
 
 
 
 . 44-00 
 
 Copper, 
 
 
 
 
 
 2-50 
 
 Arsenic, 
 
 
 
 
 
 •30 
 
 Lead f . 
 
 
 
 
 
 •20 
 
 Silica, . 
 
 
 
 
 
 7-00 
 
 100-00 
 
 This ore is burned in furnaces made somewhat similar to the sulphur 
 burners, only instead of an iron plate at bottom, there are iron bars between 
 which a current of air passes up through the ore. They are arranged in 
 rows, and all joined by a flue running along the top, which is continued to 
 
SULPHUR. 
 
 77 
 
 the chambers. A recess or oven is made in the flue, into which is put the 
 iron pot with the nitrate of soda and acid. The pyrites being once kindled, 
 burns without fuel. The greater portion of the sulphur of the ore is 
 burned off, the burned ore or cinder when properly done contains from 
 3 per cent, to 5 per cent, of sulphur. This cinder is afterwards ground 
 fine and mixed with common salt, and subjected to roasting in a close 
 furnace, whereby the copper is converted into chlorides, which is after- 
 wards dissolved out by water, and the copper precipitated as metal by 
 old iron, and then refined. The reactions and management of the vitriol 
 chambers are the same as described for brimstone. The acid, however, 
 contains arsenic— so that for some operations in the dye-house this is 
 objectionable; besides, there is a tendency in burning such ore, when the 
 heat is high, for a little iron being carried over by the arsenic, which is 
 not good for many dyeing operations. Pyrites acid is generally darker in 
 colour than that made from brimstone direct. It is seldom concentrated 
 to a higher specific gravity than 146° Twad., which can be done in lead pans. 
 It is used by soda makers for decomposing the salt, and for the manu- 
 facture of manures, and several other processes where its ordinary impuri- 
 ties are not hurtful. 
 
 Sulphuric acid may also be prepared by putting a quantity of sulphate 
 of iron into an earthenware retort, and applying a strong heat to it ; the 
 sulphuric acid is distilled over, and peroxide of iron remains. This is the 
 oldest method of obtaining sulphuric acid, and is still practised in some 
 parts of Germany. The acid so obtained is very strong, has a dark colour, 
 and gives off a quantity of white fumes ; hence it is called fuming sulphuric 
 acid. It is also called Hordhausen acid, from its being manufactured 
 there. It is a mixture of SO3 and $0 4 H 2 . When this acid is poured 
 into cold water, it produces a hissing noise, like that produced by putting 
 a red hot iron into water. This acid is excellently adapted for making 
 sulphate of indigo. 
 
 Sulphuric acid may be mixed with water in any proportion, but there 
 seems to be certain definite quantities with which it will combine with 
 water chemically. When added to water, there is always heat evolved 
 in a definite quantity, and accompanied by a condensation of bulk, as the 
 dyer may easily convince himself by taking measured quantities of strong 
 vitriol and water, and mixing them ; when the mixture is cool, he will find 
 a considerable diminution of bulk. The following experiments upon the 
 amount of condensation, and heat given out, were performed with a common 
 alkalimeter and thermometer : — 
 
78 
 
 SULPHUR. 
 
 Measure of 
 Water. 
 
 Measure of 
 Acid. 
 
 Heat -when 
 mixed. 
 
 Increase of 
 heat. 
 
 Loss by con- 
 densation. 
 
 90 
 
 10 
 
 86° 
 
 40° 
 
 5 
 
 80 
 
 20 
 
 116° 
 
 70° 
 
 7 
 
 70 
 
 30 
 
 154° 
 
 108° 
 
 8 
 
 60 
 
 40 
 
 188° 
 
 142° 
 
 H 
 
 50 
 
 50 
 
 210° 
 
 164° 
 
 n 
 
 40 
 
 60 
 
 212° 
 
 166° 
 
 n 
 
 30 
 
 70 
 
 200° 
 
 154° 
 
 9 
 
 20 
 
 80 
 
 164° 
 
 118° 
 
 8^ 
 
 10 
 
 90 
 
 136° 
 
 90° 
 
 7 
 
 The above is the mean of three trials. The proportions of acid and 
 water were taken to make 100 graduations, and mixed. The .heat was 
 observed immediately after mixing, and the mixture was kept in a stop- 
 pered bottle until cold, when it was measured by the alkalimeter, and the 
 loss by condensation noted. The heat of the water and acid separately 
 was 46°. The acid used was specific gravity 1*795, by Twaddell, 159°. 
 When the acid has the specific gravity of 150° Twad. it will crystallise in 
 large and regular crystals at a temperature of 32°, while stronger or 
 weaker acid at the same temperature will not crystallise. When this 
 takes place, it is commonly taken as an evidence of impurity in the 
 acid, which, however, it is not. These crystals take long to melt. 
 
 The ordinary impurities in sulphuric acid are lead, nitric acid, and 
 arsenic. The presence of lead is easily detected by diluting a little of 
 the acid with distilled water ; sulphate of lead is not soluble in dilute acid, 
 and when present there is produced a milkiness in the solution, as is often 
 seen in the dye-house when the acid is added to water. Nitric acid may 
 be detected, as described page 47, by putting a clean crystal of sulphate of 
 iron in the acid and heating it ; a black ring is then seen, or the smell of 
 peroxide of nitrogen perceived. Sometimes a little of this peroxide is 
 present in the acid, and either of these impurities is very bad when the 
 sulphuric acid is to be used for indigo, garancine, or any organic substance. 
 Arsenic may be detected by diluting the acid, and passing a current of 
 sulphuretted hydrogen through it, which gives a yellow precipitate when 
 arsenic is present. Should there be any sulphate of potash or soda, they 
 may be detected by" putting a few drops of acid into a small basin, and 
 saturating it with ammonia, then evaporating to dryness, and continuing 
 a strong heat until all white fumes of sulphate of ammonia cease ; nothing 
 will remain if the acid is pure. Should a little lead be present that will 
 also leave a white stain, but will turn brown by a drop of sulphide of 
 hydrogen. If iron be present the stain left will be brownish. 
 
 After ascertaining that the acid is pure, the hydrometer may be used 
 to discover its strength. The following table will be useful in this 
 operation : — 
 
SULPHUR. 
 
 79 
 
 Liquid 
 
 acid. 
 
 Specific 
 
 gravity. 
 
 Dry acid SO 3 
 in 100 parts. 
 
 Liquid 
 
 acid. 
 
 Specific 
 
 gravity. 
 
 Dry acid SO 3 
 in 100 parts. 
 
 100 
 
 1-8485 
 
 81-54 
 
 50 
 
 1-3884 
 
 40-77 
 
 99 
 
 1-8475 
 
 80-72 
 
 ^ 49 
 
 1-3788 
 
 39-95 
 
 98 
 
 1-8460 
 
 79-90 
 
 48 
 
 1-3697 
 
 39-14 
 
 97 
 
 1-8430 
 
 79-09 
 
 47 
 
 1-3612 
 
 38-32 
 
 96 
 
 1-8400 
 
 78-28 
 
 46 
 
 1-3530 
 
 37-51 
 
 95 
 
 1-8376 
 
 77-46 
 
 45 
 
 1-3440 
 
 36-59 
 
 94 
 
 1-8336 
 
 76-65 
 
 44 
 
 1-3345 
 
 35-88 
 
 93 
 
 1-8290 
 
 75-83 
 
 43 
 
 1-3255 
 
 35-06 
 
 92 
 
 1-8233 
 
 75-02 
 
 42 
 
 1-3165 
 
 34-25 
 
 91 
 
 1-8179 
 
 74-20 
 
 41 
 
 1-3080 
 
 33-43 
 
 90 
 
 1-8115 
 
 73-39 
 
 40 
 
 1-2999 
 
 32-61 
 
 89 
 
 1-8043 
 
 72-57 
 
 39 
 
 1-2913 
 
 31-80 
 
 88 
 
 1-7962 
 
 71-75 
 
 38 
 
 1-2826 
 
 30-98 
 
 87 
 
 1-7850 
 
 70-94 
 
 37 
 
 1-2740 
 
 30-17 
 
 86 
 
 1-7774 
 
 70-12 
 
 36 
 
 1-2654 
 
 29-35 
 
 85 
 
 1-7673 
 
 69-31 
 
 35 
 
 1-2572 
 
 28-54 
 
 84 
 
 1-7570 
 
 68-49 
 
 34 
 
 1-2490 
 
 27-72 
 
 83 
 
 1-7465 
 
 67-68 
 
 33 
 
 1-2409 
 
 26-91 
 
 82 
 
 1-7300 
 
 66-86 
 
 32 
 
 1-2334 
 
 26-09 
 
 81 
 
 1-7245 
 
 66-05 
 
 31 
 
 1-2260 
 
 25-28 
 
 80 
 
 1-7120 
 
 65-23 
 
 30 
 
 1-2184 
 
 24-46 
 
 79 
 
 1-6993 
 
 64-42 
 
 29 
 
 1-2108 
 
 23-65 
 
 78 
 
 1-6870 
 
 63-62 
 
 28 
 
 1-2030 
 
 22-83 
 
 77 
 
 1-6750 
 
 62-78 
 
 27 
 
 1-1956 
 
 22-01 
 
 76 
 
 1-6630 
 
 61-97 
 
 26 
 
 1-1876 
 
 21-20 
 
 75 
 
 1-6520 
 
 61-15 
 
 25 
 
 1-1792 
 
 20-38 
 
 74 
 
 1-6415 
 
 60-34 
 
 24 
 
 1-1706 
 
 19-57 
 
 73 
 
 1-6321 
 
 59-52 
 
 23 
 
 1-1626 
 
 18-75 
 
 72 
 
 1-6204 
 
 58-71 
 
 22 
 
 1-1549 
 
 17-94 
 
 71 
 
 1-6090 
 
 57-89 
 
 21 
 
 1-1480 
 
 17-12 
 
 70 
 
 1-5975 
 
 57-08 
 
 20 
 
 1-1410 
 
 16-31 
 
 69 
 
 1-5868 
 
 56-26 
 
 19 
 
 1-1330 
 
 15-49 
 
 68 
 
 1-5760 
 
 55-45 
 
 18 
 
 1-1246 
 
 14-68 
 
 67 
 
 1-5648 
 
 54-63 
 
 17 
 
 1-1165 
 
 13-86 
 
 66 
 
 1-5503 
 
 53-82 
 
 16 
 
 1-1090 
 
 13-05 
 
 65 
 
 1-5390 
 
 53-00 
 
 15 
 
 1-1019 
 
 12-23 
 
 64 
 
 1-5280 
 
 52-18 
 
 14 
 
 1-0953 
 
 11-41 
 
 63 
 
 1-5170 
 
 51-87 
 
 13 
 
 1-0887 
 
 10-60 
 
 62 
 
 1-5066 
 
 50-55 
 
 12 
 
 1-0809 
 
 9-78 
 
 61 
 
 1-4960 
 
 49-74 
 
 11 
 
 1-0743 
 
 8-97 
 
 60 
 
 1-4860 
 
 48-92 
 
 10 
 
 1-0682 
 
 8-15 
 
 59 
 
 1-4760 
 
 48-11 
 
 9 
 
 1-0614 
 
 7-34 
 
 58 
 
 1-4660 
 
 47-29 
 
 8 
 
 1-0544 
 
 6-52 
 
 57 
 
 1-4560 
 
 46-48 
 
 7 
 
 1-0477 
 
 5-71 
 
 56 
 
 1-4460 
 
 45-66 
 
 6 
 
 1-0405 
 
 4-89 
 
 65 
 
 1-4360 
 
 44-85 
 
 5 
 
 1-0336 
 
 4-08 
 
 54 
 
 1-4265 
 
 44-03 
 
 4 
 
 1-0268 
 
 3-26 
 
 53 
 
 1-4170 
 
 44-22 
 
 3 
 
 1-0206 
 
 2-45 
 
 62 
 
 1-4073 
 
 42-40 
 
 2 
 
 1-0140 
 
 1-63 
 
 51 
 
 1-3977 
 
 41-58 
 
 1 
 
 1-0074 
 
 0-82 
 
 The presence of sulphuric acid in a solution is detected by adding to 
 it a few drops of a solution of a salt of barium, which gives a white 
 
80 
 
 HYPOSULPHUROUS ACID. 
 
 precipitate not soluble in nitric acid. Sulphuric acid has a strong attraction 
 for water, so much so, that if left exposed to the atmosphere, it will absorb 
 moisture and become dilute. A saucer half filled with strong sulphuric 
 acid will become full in a few days by exposure to the atmosphere of a 
 dye-house. This shews the evil of leaving the stoppers out of the carboys, 
 or, as is often the case, leaving quantities of this acid in an open jug. 
 Animal and vegetable substances put into sulphuric acid become charred; 
 the hydrogen and oxygen of these bodies go to form water, which combines 
 with the acid, and the carbon is left as charcoal ; this same effect is pro- 
 duced upon the skin, causing a sore. The presence of organic matters 
 also tends to weaken the acid, as well as blacken it, and should therefore 
 be avoided as much as possible. This may be the proper place to refer 
 to a bad practice we have seen in the dye-house. When using vitriol, the 
 jug containing it is often placed upon the floor for convenience, and a 
 workman passing that way comes against it with his foot, and not only 
 spills the acid, but occasionally his shoe is filled with it. When this happens, 
 the first impulse, which is often obeyed, is to plunge the foot into water, 
 when, of course, the mixture of vitriol and water in the shoe is brought 
 nearly to the boiling point, as may be learned from the table above. Severe 
 accidents by this reckless habit are not uncommon. When such an 
 accident does take place, the person ought to take off his shoe and 
 stocking before putting his foot in water; and if his foot has been 
 previously dry, or merely moist, he will escape unhurt. The hand, if dry, 
 may be put into strong vitriol without burning, if washed immediately after. 
 
 Hyposulphurous Acid. — This acid is of singular composition; 
 although it is composed of equal equivalents of sulphur and oxygen, 
 what might be termed SO, yet it is represented double, S 2 0 2 . This 
 seeming anomaly is got over by supposing it to be a compound of 
 sulphurous acid with sulphur, thus : S0 2 + S. This acid is not prepared 
 directly from its elements, but formed either in combination as a salt 
 or by double decomposition. If a current of sulphurous acid gas S0 2 , 
 and sulphuretted hydrogen gas SH 2 are passed through water together, 
 four parts or equivalents of the former and two parts or equivalents of 
 the latter combine to form three equivalents of hyposulphurous acid, and two 
 of water. The formula may be accordingly this : — 4S0 2 and 2SH 2 = 3S0 2 S 
 2H 2 0. The acid when uncombined is very unstable : after exposure for 
 a short time it deposits sulphur, and sulphurous acid remains as a liquid. 
 
 When a solution of soda or potash is boiled with sulphur, there is formed 
 in the liquid hyposulphate and sulphide, of the base; supposing that soda 
 is employed, then four proportions of sulphur and six of soda produce — 
 Two hyposulphite of soda Na 2 S 2 0 3 , and 
 Two sulphide of sodium 2Na 2 S. 
 
 The hyposulphites are not yet much used in dyeing; but from the 
 property which the alkaline salts of this acid has of dissolving many metallic 
 oxides, it might undoubtedly be advantageously applied for several pur- 
 poses. Hyposulphite of soda is extensively used in photography. 
 
HYDROGEN SULPHIDE. 
 
 81 
 
 Hyposulphuric Acid. — This acid is easily formed in combination with 
 a base, by passing a current of sulphurous acid through water in which is 
 diffused a quantity of black oxide of manganese ; two proportions of the 
 acid combine with one proportion of oxygen from the manganese, and form 
 the hyposulphuric acid, which combines with the remaining manganese to 
 form the hyposulphate of manganese — 
 
 Mn0 2 2S0 2 =MnS 2 0 6 . 
 
 This acid may be obtained free from the manganese by precipitating that 
 metal, but cannot be freed from water. Its hydrate is moreover very un- 
 stable, but in union with bases it forms salts of great stability. Its formula 
 isH 2 S0 6 . 
 
 Hydrogen Sulphide. — Sulphur combined with hydrogen and forms 
 a gaseous compound termed hydrogen sulphide, or sulphide of hydro- 
 gen, H 2 S, which is sometimes not inappropriately termed hydrosulphuric 
 acid, as the gas has acid properties. This gas is prepared by acting 
 upon a metallic sulphide, with an acid, in this manner: — A few pieces 
 of protosulphide of iron are put into a glass or porcelain vessel con- 
 taining a little water, and a small quantity of sulphuric or hydrochloric 
 acid is added; a gas of a strong, suffocating smell, like rotten eggs, 
 immediately begins to come off, which is hydrogen sulphide. The reaction 
 which takes place is as follows : — 
 
 Sulphide of iron, 
 Sulphuric acid, 
 
 Sulphide of hydrogen. 
 
 Sulphate of iron. 
 
 This gas is used as a test for metals : it is absorbed by water, and may 
 thus used in solution as a test. It is also taken up in great quantity 
 a solution of ammonia, forming hydrosulphide 
 of ammonia, or ammonium sulphide, which is 
 also much used as a test. When used in the 
 gaseous state, such an apparatus as the 
 accompanying will serve. The sulphide of 
 iron, or other sulphide, is put into the bottle 
 a, containing some water, and the acid is 
 added by the long funnel d. The gas escapes 
 by the tube e,/, and passes through the solu- 
 tion to be tested, contained in the glass g. 
 
 The same apparatus serves for passing the 
 gas through water or liquid ammonia, when 
 it is required to produce the test in solution. 
 
 The precipitates formed by passing this gas 
 through solutions of various substances aro 
 very characteristic. Thus, a solution containing — 
 
 p 
 
 be 
 
 by 
 
PHOSPHORUS. 
 
 
 Antimony produces 
 
 Orange precipitate. 
 
 Tin and arsenic ... . . .. 
 
 Yellow precipitate. 
 
 Manganese 
 
 Flesh coloured precipitate. 
 
 Zinc . .’ 
 
 White precipitate. 
 
 Lead, copper, iron, &c., 
 
 Black precipitate. 
 
 In acid solutions of some of these substances, such as manganese, zinc, and 
 iron, the metal is not precipitated by the gas — the solution has to be made 
 alkaline, or ammonium sulphide is used to obtain these results. 
 
 Sulphide of hydrogen is evolved from decaying animal and vegetable 
 matters, and from dunghills, common sewers, and putrefying bodies that 
 contain sulphur. It is very deleterious to health, and care should be 
 taken to avoid breathing it. The effect of this gas upon many dyes is 
 so very great that the slightest quantity in the atmosphere is hurtful. It 
 gives to chrome yellows and oranges a smoky appearance, which cannot 
 be removed ; and to spirit reds it gives a rusty brown appearance. 
 Wherever, indeed, there is a metal present in the dye, this gas affects 
 the colour. Sulphurous fumes given off by burning sulphury coals in a 
 drying stove often produce similar effects. We have seen a whole 
 stove-charge of goods, yarn and cloth, spoiled in this way — the colours 
 appearing as if dried in smoke, and the watchman superintending the 
 stove, notwithstanding his protestations that there was no smoke, com- 
 pelled to bear the blame of negligence. 
 
 Selenium (Se 79, 46). 
 
 This element very much resembles sulphur in its properties and in 
 some of its combinations. It is solid, of a dark brown colour and metallic 
 lustre, and is found in Nature in combination with some of the metallic 
 sulphides, as those of copper, silver, lead, &c. It is very rare, and as it 
 has only been obtained in minute quantities, it has not yet been introduced 
 in the arts, or applied to any useful purpose. 
 
 Phosphorus (P 31.) 
 
 Phosphorus is a soft, solid substance, of a light amber colour, and 
 insoluble in water. It is very abundant in Nature in combination with 
 other substances, but principally with lime, giving the extensive supply of 
 mineral phosphates used by chemical manure -makers, both as crystallised 
 minerals and fossil coprolytes, and also the principal compound of the 
 bones of animals. It is exceedingly inflammable, oxidises rapidly when 
 exposed to the air, and emits light visible in the dark, from which circum- 
 stance it derives its name. It is manufactured from the bones of animals, 
 by various complicated methods, not very easily imitated on a small scale. 
 
IODINE. 
 
 83 
 
 This element unites with oxygen in various proportions, and most of 
 the compounds formed when united with water have acid properties, as — 
 
 Hypophosphorous acid, P0 2 H 3 . 
 
 Phosphorous acid, P0 3 H 3 . 
 
 Phosphoric acid, P0 4 H 3 . 
 
 These acids all unite with bases, forming salts which are interesting in 
 their relations to each other, and also to salts of other acids. Phosphoric 
 acid and the phosphates evince peculiar properties in combining with 
 various proportions of water, and producing compounds which differ 
 characteristically from one another. These combinations have been 
 extensively investigated by the late Professor Graham and other chemists. 
 Most of the phosphates are tribasic, having three of the metal Or base 
 to one of acid. We are not aware that any of these salts are used in the 
 operations of dyeing, except in so far as they constitute a portion of 
 the salts in dung, and the substance called dung substitute , used in dye- 
 ing turkey reds and other madder colours. 
 
 Phosphorus combines also with hydrogen, nitrogen, chlorine, and 
 sulphur, and likewise with many of the metallic elements, forming the 
 class of compounds termed phosphides. 
 
 Iodine (1 127). 
 
 Iodine is obtained from the ashes of seaweed, known as kelp. The 
 ashes are put into water, and the soluble portions are withdrawn, and 
 boiled down. During the boiling, common salt and other salts are 
 deposited and withdrawn ; and when the liquid is reduced to a very 
 small quantity and attains a dark colour, a little sulphuric acid is added ; 
 the whole is then allowed to remain at rest for a day or two. The 
 liquor is then mixed with oxide of manganese, and put into a retort, 
 to which heat is applied. The iodine distils over, and is condensed in 
 receivers fitted to the retort. Mr. Stanford has improved upon the 
 formation of kelp. He dries the seaweed and distils it in iron retorts, 
 getting gas, ammonia, &c. ; the salts are dissolved from the charcoal and 
 treated as stated. 
 
 Iodine is a solid substance, with a metallic lustre, and a bluish- 
 black colour ; it stains the hands yellow, and is volatile at a low 
 heat, rising in vapour of a beautiful violet colour. It combines with 
 nearly all the non-metallic elements, and also with the metals ; with many 
 of the latter it forms compounds having beautiful colours, suitable in 
 every way as dyes. But from the volatile nature of iodine, the colours 
 produced by it are fugitive, and do not bear exposure. Many attempts 
 have been made to employ the salts of iodine as dye-drugs, and to fix 
 the colour, but they have all failed. It is now used in the preparation 
 of Hoffman’s blue. 
 
84 
 
 BROMINE. 
 
 The compounds of iodine with oxygen are the two acids — 
 
 Iodic acid, ,.HIOs | Periodic acid, HI0 4 , 
 
 These acids combine with bases to form salts, termed iodates. Iodine 
 forms an acid with hydrogen, named — 
 
 Hydriodic acid, HI. 
 
 The salts which this acid forms are termed hydriodates. 
 
 Iodine combines with starch, and forms a deep blue violet colour, 
 which soon passes away. Starch is used as a test for the presence of 
 free iodine; or, if combined with a base such as potash, by adding a 
 little acid to take the potash, iodine is liberated and colours the starch. 
 The principal iodine compound with which experiments upon the colours 
 produced by iodine and the metals is the iodide of potassium, KI. This is 
 easily prepared by boiling iodine in a solution of caustic potash to 
 dryness, then fusing the dry mass in an iron vessel or crucible. The result 
 is iodide of potassium, which is easily soluble in water. This salt is 
 abundant in commerce, and always very pure. A little of the solution 
 of this salt added to a salt of lead produces a beautiful yellow precipitate, 
 which, when boiled, and the clear of the liquid set aside to cool, gives 
 brilliant golden-coloured crystals in scales. The salts of mercury give 
 with iodide of potassium a deep orange red precipitate. Iodine of potassium, 
 indeed, gives precipitates and colours with the salts of nearly all the metals ; 
 and, were it possible to render the colours it affords permanent, it would no 
 doubt become a most useful drug in the hands of the operative dyer. 
 
 Bromine (Br 80). 
 
 Bromine is another element obtained from the ashes of seaweeds, 
 but not in nearly so great abundance as iodine. When all the iodine 
 is distilled off more oxide of manganese is added to the still, and the heat 
 continued, bromine comes over and is condensed, in passing through a 
 leaden pipe or worm placed in cold water. It is a liquid at ordinary 
 temperatures ; has a deep red colour, and is much heavier than water, in 
 which it is generally kept to prevent it volatilising, as it does rapidly when 
 exposed to the air. It has a very penetrating odour, and its fumes destroy 
 vegetable colouring matters, leaving merely a yellow stain. 
 
 Bromine is known to combine with oxygen and hydrogen in various 
 
 proportions, forming — 
 
 Hypobromous acid, HBrO. 
 
 Bromic acid, HBr0 3 . 
 
 Perbromic acid, HBr0 4 . 
 
 Bromic acid, which combines with bases, forming the salts termed bro- 
 mates. With hydrogen it combines and forms hydrobromic acid = HBr, 
 
BORON. 
 
 85 
 
 the salts of which are termed hydrobromates. It also unites directly 
 with some of the other elements forming bromides, of which the bromide 
 of potassium is an example, a salt much used in medicine. The com- 
 pounds of bromine with some of the metals might also form dyes were 
 they procured abundantly; but the objection to the use of iodides is also 
 applicable to bromides — they are unstable, and vanish on exposure. 
 
 Fluorine (FI 19). 
 
 This element is only known in combination, and has never been 
 obtained free. By its powerful attraction for every other substance, it 
 fulfils in some degree the old hypothetical notion of a universal solvent. 
 It is, however, very abundant in Nature combined with calcium as a 
 fluoride, forming the mineral jiuor spar , CaFl ; it is also found in bones, 
 blood, and milk. It is not known to combine with oxygen, but it com- 
 bines very readily with hydrogen, and forms hydrofluoric acid = HF1. 
 This acid may be evolved from fluor spar by acting upon it with sulphuric 
 
 I acid ; it dissolves glass, and all matters containing silica, and therefore 
 cannot be kept in glass, china, or earthenware vessels ; it dissolves all 
 metals except lead, silver, gold, and platinum ; it can be kept in vessels 
 made of any of these metals ; lead bottles were commonly used until gutta- 
 percha was introduced, and vessels made of this material are now used. By 
 mixing fluor spar and pieces of glass or fine sand, and acting upon the 
 mixture by strong sulphuric acid, an acid gas is given off, called fluosilicic 
 acid = SiFl 4 , which, together with hydrofluoric acid, combines with water, 
 
 II and is termed Tiydrofluosilicic acid. This solution is occasionally used in 
 the laboratory as a test for potash and soda. 
 
 — 
 
 Silicium (Si 28). 
 
 Silicium is a light brown powder. It is one of the most extensively 
 diffused elements in Nature, but it always exists in combination with 
 oxygen, forming silica or silicic acid — Si0 2 . The substances known as 
 flints , agates , quartz , sand, &c., are nearly pure silica, and every other 
 earthy substance in nature contains more or less silica combined with it. 
 
 I This substance is of essential importance to the potter and glassmaker, 
 but it is of little consideration in dyeing. 
 
 Boron (B 11). 
 
 Boron is a solid, and is generally obtained as a greenish-brown powder, 
 destitute of metallic lustre. It is not found in Nature except in combina- 
 tion with oxygen and water, forming boracic acid = B0 9 II 8 . This acid 
 
86 
 
 CARBON. 
 
 combines with bases forming borates but it is found in Nature uncom- 
 bined, especially among the volcanic products of the Lipari Islands. The 
 sources of the compounds of boron are, however, some springs in India, 
 and the waters of Sasso, which hold in solution a quantity of borate of 
 soda (borax). In some lakes in the neighbourhood of volcanoes there are 
 great quantities of boraciG acid uncombined. These waters are concen- 
 trated by evaporation sufficient to allow the acid to crystallise, and in 
 this state it is known in commerce as raw borax. Arrived in this country 
 it is dissolved and saturated with soda to form borate of soda, which is 
 obtained in large crystals ; this is the refined borax of commerce, and the 
 principal compound of boron known in the arts. It is much used in 
 medicine and as a flux in the assaying of metals. 
 
 Carbon (C 12). 
 
 Carbon is very extensively diffused throughout Nature, and the complete 
 description of this element and its compounds would embrace the whole 
 chemistry of organic matter. It is met with also in various forms and 
 combinations in the mineral kingdom. Carbon exists pure in diamond 
 and coal, and forms nearly the whole of plumbago and graphite (popularly 
 llacklead). It may be obtained by submitting either animal or vegetable 
 matter to a high heat in a close vessel : the oxygen, hydrogen, and nitrogen 
 of these bodies pass off, and the carbon is left. Charcoal is therefore 
 carbon with a little earthy matter ; and coke, ivory-black, and lampblack, 
 are other familiar names for it in an impure state. These substances differ 
 in character from each other in having different proportions of earthy 
 ingredients in combination or mixture with the principal element. Carbon 
 is infusible, therefore we only know it in a solid form. It possesses many 
 singular properties connected with the principles of dyeing ; some of these 
 we will state here, and reserve the applications till we come to consider the 
 methods and theory of dyeing. 
 
 Carbon has the property of absorbing gases within its pores. One 
 cubic inch of the best charcoal made from boxwood has been found to 
 absorb or imbibe the following quantities of the different gases named in 
 first column. One volume of carbon from the shell of a cocoa-nut quenched 
 in mercury absorbs the following quantities in second column : — 
 
 Cubic inches. 
 
 90 Ammoniacal gas.. 
 
 85 Hydrochloric acid gas. 
 65 Sulphurous acid. 
 
 55 Sulphide of hydrogen. 
 40 Peroxide of nitrogen. 
 35 Carbonic acid. 
 
 9 Oxygen. 
 
 7 Nitrogen. 
 
 T7 Hydrogen, 
 
 171 Ammonia. 
 
 107 Cyanogen. 
 
 86 Nitrogen dioxide. 
 67 Carbonic acid. 
 
 21 Protoxide carbon. 
 18 Oxygen. 
 
CARBONIC OXIDE. 
 
 87 
 
 This curious property is not well understood : it is generally supposed 
 that it results from the powerful cohesive attraction between the gas and 
 the surface of the charcoal particles, by which means the gas is liquefied. 
 171 volumes of gas condensed into one volume should produce a great 
 amount of heat. This has not been referred to, so far as we have seen. 
 Somewhat analogous to this property is its power of absorbing or imbibing 
 colouring matters, and on this account it is extensively used for discolouring 
 sugar. This power of taking up colours from solution is possessed in the 
 highest degree by bone black — that is, ground bone charcoal, although 
 this may be said to be the most impure form of charcoal. Its composition 
 when clean bones are burned is — 
 
 Carbon, 100 
 
 Phosphate of calcium, 88*0 
 
 Other salts, 2-0 
 
 100-0 
 
 This, it will be seen, is rather a highly porous mass of phosphate of calcium 
 with finely divided carbon diffused through it. After being used for a short 
 time it loses its power of decolouring the syrup, but is revivified by wash- 
 ing and re-heating in close vessels. Bone black has also the property of 
 abstracting lime and acetate of lead from solutions. Other kinds of char- 
 coal have also the power of extracting colouring matters from solutions. 
 Different kinds of charcoal possess this property in different degrees. 
 Charcoal has also the property of keeping water sweet for a long time, 
 and of decomposing certain gases, and, as proposed by Dr. Stenhouse, has 
 been used as a filter for obnoxious gases, which it decomposes. It is 
 thus of use for sanitary purposes. 
 
 This property of absorbing colours is considered of the same nature — 
 an attraction by the charcoal surfaces — and it is found in some cases to be 
 sufficiently strong to overcome chemical affinity. The same property of 
 imbibing colours is possessed by other porous matters to some extent; and 
 the porous nature of the fibre of cotton, woollen, and silk may exercise an 
 influence of a similar kind — a subject which we intend to consider further on. 
 
 Carbon combines with oxygen in three proportions, forming — 
 
 Carbonic oxide, CO. 
 
 Anhydrous carbonic acid, C0 2 . 
 
 Hydrous do., C0 3 II 2 . 
 
 Anhydrous oxalic acid, C 2 0 3 . 
 
 Hydrous do., Ca0 4 II 2 . 
 
 Carbonic Oxide is obtained by heating together strong vitriol and 
 crystallised oxalic acid. This operation may be performed in a retort or 
 flask, as described for hydrogen (page 31); the action which takes place is — 
 
88 
 
 OXALIC ACID. 
 
 Crystallised 
 oxalic acid, 
 
 Strong sul- 
 phuric acid, 
 
 ” Carbon,... 
 Carbon,... 
 J Oxygen,.. 
 Oxygen,.. 
 Oxygen,.. 
 ^ Water, ... 
 
 [■ Sulphuric 
 
 Oxide of carbon. 
 Carbonic acid. 
 
 Sulphuric acid. 
 
 The action is simply the sulphuric acid taking the water from the 
 crystallised oxalic acid and setting the elements free. By passing the 
 gases through a solution of caustic potash or lime water, the carbonic acid 
 is absorbed, and carbonic oxide is obtained pure. It is a colourless gas, 
 inodorous, and burns with a blue flame. It is the presence of this gas 
 which gives the blue flame of a coke fire. The product of its combustion 
 is carbonic acid. 
 
 Carbonic Acid. — When carbon is brought to a red heat in air, it burns 
 and dissipates; oxygen combines with the carbon, and produces gaseous 
 carbonic acid. This gas is generally obtained for experiment from its 
 compounds. Thus, when a few pieces of marble or chalk are put into 
 a flask or retort, and some dilute muriatic acid is added, effervescence takes 
 place, and the action is — 
 
 f Carbonic acid,... Carbonic acid. 
 
 Marble, ... < Calcium, .... 
 
 I Oxygen, .... 
 
 Two muriatic { Hydrogen 2 , 
 
 acid, \ Chlorine 2 , Ax Chloride calcium. 
 
 or CaC0 3 + 2 HC1 = CaCl H 2 0C0 2 . 
 
 Carbonic acid is absorbed by the water over which it is collected in 
 considerable quantity ; but the materials from which it is prepared are so 
 cheap, that this absorption does not signify much in an experiment. The 
 gas is colourless, and heavier than atmospheric air, so that it may be poured 
 from one vessel to another as if it were a liquid. A light is instantly extin- 
 guished by immersion in it, and an animal soon dies if kept in air con- 
 taining nine per cent, of it. Combined with water, it manifests acid 
 properties, and gives the water an agreeable taste and pungency, as 
 experienced in aerated waters. It combines readily with alkaline and 
 earthy bases, producing carbonates. Its affinity for lime is very great ; 
 but it is liberated from all its compounds with effervescence by a stronger 
 acid. When the dry gas is passed over redhot charcoal, it is decomposed; 
 the charcoal combines with half its oxygen, and forms oxide of carbon. 
 
 Oxalic Acid has been long known in commerce as salt of sorrel. 
 It was formerly obtained from the Mails acete sella, a plant which contains 
 
CYANOGEN. 
 
 89 
 
 it as oxalite of lime ; but it is now manufactured in large quantities from 
 sugar and starch, by acting upon these substances with nitric acid, 
 which oxidises and • decomposes them, giving off carbonic acid and 
 nitrous gas; and from sawdust, by acting upon it with caustic potash. 
 The oxalic acid crystallises from the solution with water, which, as has 
 been shewn at page 87, is essential to its existence. It combines with 
 bases, and forms salts of great importance in the laboratory. Thus 
 the oxalates of potash and ammonia are excellent tests for lime; and 
 they are also of some importance in the dye-house. Oxalic acid is 
 easily distinguished from any of the alkaline and earthy salts, such as 
 the sulphate of magnesia (Epsom salts), for which it has occasionally, 
 through ignorance, been mistaken by its strong acid character. It is 
 easily distinguished from magnesia ; by heating it to redness upon a piece 
 of metal it will all evaporate, and leave no residue, while the mag- 
 nesian salt leaves one. It sometimes contains nitric acid, peroxide of 
 nitrogen, and Epsom salts ; the two first may be detected by dissolving 
 a little of the acid, and adding a minute colouring of sulphate of 
 indigo, and then boiling: the presence of these impurities decolours the 
 indigo. The presence of Epsom salts may be detected by chloride of 
 barium, or by evaporation, as directed above. There is often about one 
 per cent, of this salt in the commercial oxalic acid. 
 
 This acid has been long used in the dye-house, and acts powerfully 
 upon many substances, but it is not now so generally used. A curious 
 salt, of a beautiful colour, may be obtained by taking — 
 
 One part of bichromate of potash, 
 
 Two of binoxalate of potash, 
 
 Two of oxalic acid ; 
 
 and dissolve the whole together in hot water, carbonic acid is evolved, 
 and a double salt of oxalate of potash and chrome, having a fine purple 
 colour, is formed in solution. Crystals of the salt, possessing a very 
 deep blue colour, may be obtained by evaporation. 
 
 Cyanogen. — Carbon combines with nitrogen, and forms cyanogen, a 
 very important compound, consisting of one equivalent of nitrogen and 
 one equivalent of carbon = CN or Cy. It is a gas, and has the property 
 of combining with other elements, as if it were itself an element. It 
 belongs, therefore, as was stated at page 27, to the class of compounds 
 known as salt radicals. It is not obtained by directly bringing nitrogen 
 into contact with carbon, but by the decomposition of animal compounds in 
 contact with metallic bases, as we will have occasion to describe further 
 on. The gas is obtained for experiment from its salts generally by heat- 
 ing cyanide of mercury in a retort. The mercury comes over in a metallic 
 state, and the cyanogen escapes as gas, and may be caught at the pneu- 
 matic trough. Cyanogen combines with oxygen, and forms an acid called 
 cyanic acid, and this combining with bases forms cyanates. 
 
90 
 
 CYANOGEN. 
 
 Cyanogen combines also with hydrogen, and forms an acid termed 
 hydrocyanic acid, or more commonly prussic acid, CN + H or HCy ; 
 and although certain salts are termed prussiates, from this acid being first 
 termed prussic acid, they are properly cyanides. Some of them are highly 
 important in the arts, and will be noticed in their proper places. 
 
 Cyanogen also combines with the metals in the same manner as 
 chlorine and iodine, and forms that class of salts termed cyanides , which 
 will be described under metallic salts. 
 
 Carbon combines with hydrogen in various proportions, forming 
 different kinds of gases, such as light carbide of hydrogen, olefiant gas, 
 and common coal gas, and some other hydrocarbons have those gases 
 as constituents. Since the introduction of gas and paraffin to the manu- 
 facturing arts, the investigation into the compounds of carbon and hydro- 
 gen has yielded a large harvest of important discoveries, which is not yet 
 exhausted. Some are liquid, such as benzine, petroleum oils, &c. Some are 
 solid, like paraffin and anthracine, while some are gaseous, such as referred 
 to above; and to systematise these combinations they have been formed into 
 groups with suitable names, according to certain laws. Thus, for example — 
 
 Methane, or marsh gas, or light carburetted hydrogen = CH 4 . 
 
 Starting from this, there is a series that seems to be methane with an 
 addition of CH 2 , thus — 
 
 Ethyl hydride, . 
 
 . . C 2 H 6 . 
 
 Propane, or prop}d hydride, 
 
 c 3 h 8 . 
 
 Quartane, or butyl hydride, 
 
 . . . C,H I0 . 
 
 Quintane, or amyl hydride, 
 
 C 5 H, 2 . 
 
 and so on for a long series. 
 
 Again, there is olefiant gas, or heavy carburetted hydrogen, now called 
 
 Ethene, composed of . 
 
 . . . c 2 h 4 . 
 
 Propene, or propylene, 
 
 . . c 3 H 6 . 
 
 Quartene, or butylene, 
 
 . . . C 4 H 8 . 
 
 Quintene, or amylene, 
 
 . . . c 6 h 10 . 
 
 and so on for another long series. 
 
 There are several other series 
 
 equally interesting chemically, and of great importance in the study of 
 organic matters, but meantime of little interest to the dyer, except to shew 
 how apparently small discoveries effect great and important changes, and 
 that upon such changes has risen coal-tar colours, to be noticed in their 
 proper place. Carbon also combines with sulphur, and forms with it a 
 colourless, volatile, and inflammable liquid, possessing a most putrid smell, 
 termed bisulphide of carbon. It is much used in the arts as a solvent for 
 caoutchouc and gutta-percha in vulcanising, and also in the extraction of 
 quinine. In organic bodies, carbon is combined with oxygen, hydrogen, 
 and nitrogen, in an endless variety of proportions. Some of these com- 
 pounds will be brought under notice when treating of the organic sub- 
 stances which fall within the scope of our subject. 
 
METALLIC SUBSTANCES. 
 
 General Properties of Metals. 
 
 We now proceed to consider that division of the elements commonly known 
 as metals. To define the peculiar properties of a metal is somewhat diffi- 
 cult, for whichever property we select, it is either absent in some metal, or 
 is possessed by some non-metallic element. A few of the more prominent 
 physical properties may, however, be named. 
 
 1st. They all possess a peculiar lustre. 2nd. They all reflect light, 
 which is the cause of that lustre. 3rd, They are all fusible by heat. 4th. 
 They are all conductors of heat. 5th. They have all to a certain degree the 
 property of extension: they are malleable under the hammer, and laminable 
 under the roller ; and being capable of extension by drawing into wire, 
 they are termed ductile. 
 
 There are also chemical distinctions which are much more universal. 
 They are all basic , that is to say, capable of combining with oxygen, and 
 forming oxides ; and with acids they form a series of compounds termed 
 salts, of which the metal is termed the base. It is on account of the 
 possession of these general properties that hydrogen is regarded as a metal 
 in a gaseous state: it is pre-eminently basic. 
 
 When metals combine with one another the compound is termed an 
 alloy. Brass is a chemical mixture of copper and zinc; and German silver 
 is a like mixture of copper, zinc, and nickel; both brass and German silver 
 are therefore alloys. Alloys retain most of the physical properties of the 
 metals of which they consist. A great many of the recently discovered 
 metals are very rare, and have only been found in certain localities, and in 
 minute quantities. The alkalies and earths were long looked upon as 
 elements ; they had never, indeed, been decomposed till 1807. What was 
 until that time known as the element 
 
 Potash, we now know to be the oxide of the metal Potassium. 
 
 Soda, „ 
 
 55 
 
 „ Sodium. 
 
 Lithia, „ 
 
 55 
 
 ,, Lithium. 
 
 Lime, „ 
 
 55 
 
 ,, Calcium. 
 
 Barytes, ,, 
 
 55 
 
 ,, Barium. 
 
 Magnesia, „ 
 
 55 
 
 ,, Magnesium. 
 
 Alumina (pure clay), 
 
 55 
 
 ,, Aluminum. 
 
 Potassium (K 39 1). 
 
 Sir H. Davy decomposed potash by a powerful electric current, and 
 demonstrated it to be the oxide of a peculiar metal which he termed 
 
92 
 
 POTASH. 
 
 potassium. This metal may be obtained by roasting a quantity of 
 bitartrate of potash (cream of tartar) in a covered crucible : the immediate 
 product is what is termed by assayers black flux ; then, mixing this matter 
 with a quantity of finely ground charcoal, and putting the mixture into a 
 wrought-iron bottle, or submitting it to a high heat, the metal comes over, 
 and is caught in a vessel containing naphtha, or a hydrocarbon that contains 
 no oxygen. Only such a fluid can be used for this purpose, as the attrac- 
 tion of potassium for oxygen is so great that it decomposes all substances 
 which contain that element. 
 
 Potassium is a white metal, with a lustre somewhat like silver; at 
 ordinary temperatures it is soft, and may be flattened between the fingers, 
 but at 32° Fah. it is hard and brittle. It melts at 150°. When exposed 
 to the air it becomes covered immediately with a white crust of oxide. It is 
 lighter than water, and when thrown upon that fluid it swims, and instantly 
 bursts into flame, combining with the oxygen of the water so rapidly as to 
 produce heat sufficient to kindle the hydrogen as it makes its escape. The 
 metal not only fuses, but a small portion of it goes off as vapour, and burn- 
 ing with the hydrogen produces a beautiful red-coloured flame. In this 
 experiment potash is formed and is dissolved in the water. Pure potash is 
 the oxide of the metal potassium, but it is not prepared from the metal for 
 manufacturing purposes. 
 
 Potash — Sometimes termed the vegetable alkali — takes its name from 
 its having been prepared in iron pots. When a piece of wood or 
 other vegetable substance is slowly burned until all inflammable matters 
 are consumed, there is left a white substance called ash. This ash 
 consists of the mineral ingredients of the vegetables. The potash and 
 other soluble ingredients are extracted by treating the ash with water. 
 
 Different vegetables vary greatly in the amount of ash they contain and 
 the amount of potash that is in the ash. The following shews this in a 
 few of the most common vegetable substances : — 
 
 
 Per cent, of Ash. 
 
 Per cent, of 
 Potash in Ash. 
 
 Oak, as it grows, 
 
 3-30 
 
 1-53 
 
 Birch, .... 
 
 1-00 
 
 9-63 
 
 Firs, average, 
 
 0-92 
 
 8-75 
 
 Elm, .... 
 
 2-28 
 
 3-90 
 
 Elder, . . . 
 
 1-64 
 
 1-08 
 
 Hazel, .... 
 
 0*50 
 
 2-80 
 
 Whin, .... 
 
 1-64 
 
 2-40 
 
 Broom, 
 
 1-48 
 
 3-00 
 
 Potato stems (shaws), 
 
 . 15-00 
 
 4-69 
 
 Pease straw, . . . 
 
 8 
 
 . 20 
 
 Oat straw, . 
 
 5-10 
 
 0-87 
 
 Wheat straw, 
 
 7 
 
 3-90 
 
 Nettles, 
 
 . 10-67 
 
 . 25 
 
 Thistle, 
 
 4-03 
 
 5-00 
 
 Ferns, average, . 
 
 3-30 
 
 6-22 
 
POTASH. 
 
 93 
 
 The quantity of potash in any vegetable varies according to the 
 nature of the soil ; and potash to some extent is essential to the health of 
 the vegetable, so that care should be taken by farmers and others that 
 manures containing potash be supplied to the soil. 
 
 The average quantity of ash obtained from wood is about one per cent. 
 In America, where wood is an incumbrance, it is felled, piled up in masses, 
 and burned for the manufacture of potash. The ashes of the wood are 
 collected and put into cisterns provided with false bottoms, and run-olf 
 plugs underneath. A quantity of water is thrown upon the ashes in the 
 cistern, and after stirring and settling a few hours, all the soluble matters 
 are dissolved, and the liquor is drawn off by the plug-hole and evaporated 
 to dryness, the residue is afterwards fused at a red heat into compact masses, 
 and in this state constitutes the commercial black ash . As other matters 
 in the ash besides the potash are soluble in water, the black ash thus 
 prepared contains these substances as impurities. These are mainly 
 sulphites, sulphides, and chlorides of potash and soda, along with some 
 earthy matters. 
 
 Pearl-ash is prepared by calcining the black ash in a reverberatory 
 furnace until all the carbonaceous matters and the sulphur are driven off. 
 The remaining mass is then dissolved in water, and the solution evaporated 
 to dryness in large iron pans. Towards the conclusion of the process the 
 mass is stirred to give it a lumpy granulation. This ash contains much less 
 extraneous matter than black ash. It is more fully carbonated. Dr. Ure 
 states (Dictionary of Arts , &c.) that he found the best pink coloured 
 Canadian potash to contain 60 per cent, of real potash, while the best pearl- 
 ash contained only 50 per cent. These are the two states in which potash 
 is used in the dye-house. The methods for testing the quantity of real 
 alkali they contain will be given when we come to speak of soda. 
 
 The following are a few analyses of pot and pearl-ash : — 
 
 Potash. 
 
 Carbonate of potash, 
 
 43-68 
 
 24-57 
 
 Peakl. 
 
 Carbonate of potash, 
 
 56-01 
 
 71-38 
 
 Hydrate of potash, . 
 
 49-68 
 
 44-43 
 
 Hydrate of potash, . 
 
 5-61 
 
 ... 
 
 Sulphate of potash, . 
 
 4-07 
 
 16-14 
 
 Sulphate of potash, . 
 
 27-70 
 
 14-38 
 
 Chloride of sodium, . 
 
 1-64 
 
 4-40 
 
 Chloride of sodium, . 
 
 10-49 
 
 • • • 
 
 Carbonate of soda, . 
 
 ... 
 
 4-27 
 
 Carbonate of soda, . 
 
 ... 
 
 2-31 
 
 Insoluble matter, and 
 other matters, 
 
 0-72 
 
 6-19 
 
 Insoluble matter, and 
 other matters, 
 
 0-19 
 
 3.73 
 
 
 99-79 
 
 100-00 
 
 Moisture, . 
 
 Chloride potassium, . 
 
 100-00 
 
 4-57 
 
 3-63 
 
 100-00 
 
 These are American ashes ; but there are also large imports of potash 
 from Russia and other parts of the Continent. 
 
 The principal use of potash is to destroy or take off any grease or oil 
 
94 
 
 POTASH. 
 
 which may exist in or upon the fibre to be dyed, and it does this by com- 
 bining with these substances and forming soap, which, being soluble in 
 water, is easily removed. Dyers are often in the habit, when about to steep 
 or boil their goods, of simply adding to their solution or boiler some pearl 
 ash or potash, but when the alkali is in union with an acid such as car- 
 bonic acid forming a carbonate, its power of combining with oil or grease 
 is to a great extent neutralised. The white obtained upon the fabric may 
 be good enough, and as was before remarked when speaking of chlorine, a 
 good white can be got without potash; but it is not so permanent. If 
 grease or oil spots be present they are not removed, only concealed, and 
 the dyer is often annoyed by large resist spots which he cannot account for, 
 and which are not so easily removed after the goods are bleached as before. 
 The alkali, whether pearl or potash, before being used ought to be made 
 caustic, that is, deprived of its carbonic aeid, and converted into hydrate of 
 potash. This is done by boiling the carbonated alkali with newly slaked 
 lime ; the lime combines with the carbonic acid of the alkali and falls to the 
 bottom, while the caustic alkali remains in solution. Without detailing 
 the various methods practised, some of which are not good, we shall rather 
 give what we consider the best. The carbonate of potash ought to be dis- 
 solved in not less water than six times its weight; it is better, however, to 
 use ten times its weight, as if a less quantity of water be used, the potash is 
 not deprived of all its carbonic acid. The reason assigned for this singular 
 phenomenon is, that both caustic potash and carbonate have a strong 
 affinity for water, and when less than six times its weight is used, there is 
 sufficient water to supply the carbonate but not the caustic alkali, and 
 hence the carbonate is not all converted into the caustic state. The exact 
 quantity of lime is not material, provided there be enough. The lime 
 ought to be added when the alkali is boiling, and from time to time, until 
 a little of the solution being taken out, it does not effervesce by the addition 
 of a little dilute sulphuric acid. If strong acid is used, care must be taken 
 before adding it that the solution be cold, for if not it will spurt, and may 
 injure the manipulator. The best way is to take a little of the alkali and 
 dilute it with cold water, and then add the acid. When there is no effer- 
 vescence, the alkali is caustic. The boiling is then stopped, and when the lime 
 settles the clear liquor is taken off and kept in an iron vessel covered closely, 
 as the potash readily takes up carbonic acid from the air. For bleaching, 
 and other cleansing operations, and also for many purposes in the dye- 
 house, the supply should be taken from this stock vessel. It will be 
 necessary, however, that the operator knows the exact strength of the solu- 
 tion, in order that he may know the proper quantity of it he ought to 
 use for particular purposes. On this point a pretty correct approximation 
 is obtained by knowing the percentage of pearl or potash used in making 
 the solution, and then calculating the quantity to each gallon: but greater 
 exactness is attained by using the following table (drawn up by Dr. Dalton), 
 in which the specific gravity is supposed to be known, and hence the 
 quantity of the alkali present in solution : — 
 
POTASH. 
 
 93 
 
 Potash, per cent, 
 in solution. 
 
 Specific gravity 
 of solution. 
 
 Specific gravity 
 by Twaddell’s. 
 
 Boiling point of 
 solution. 
 
 72-4 
 
 2-000 
 
 200° 
 
 600° 
 
 63-6 
 
 1-880 
 
 176 
 
 420 
 
 56-8 
 
 1-780 
 
 156 
 
 360 
 
 51-2 
 
 1-680 
 
 136 
 
 320 
 
 46-7 
 
 1-600 
 
 120 
 
 290 
 
 42-9 
 
 1-520 
 
 105 
 
 276 
 
 39-6 
 
 1-470 
 
 94 
 
 265 
 
 36-8 
 
 1-440 
 
 88 
 
 255 
 
 34-4 
 
 1-420 
 
 84 
 
 246 
 
 32-4 
 
 1-390 
 
 78 
 
 240 
 
 29-4 
 
 1-360 
 
 72 
 
 234 
 
 26-3 
 
 1-330 
 
 66 
 
 229 
 
 23-4 
 
 1-280 
 
 56 
 
 224 
 
 19*5 
 
 1-230 
 
 46 
 
 220 
 
 16-2 
 
 1-190 
 
 38 
 
 218 
 
 13- 
 
 1-150 
 
 30 
 
 215 
 
 9-5 
 
 1-110 
 
 20 
 
 214 
 
 4-7 
 
 1-060 
 
 12 
 
 213 
 
 In the first column of this table the percentage of alkali is given by- 
 weight. Thus, a gallon of water is 10 lbs. weight, therefore a gallon of 
 the caustic ley solution will have one-tenth part of the potash indicated by 
 the table according to the specific gravity. Say the solution stands 30° 
 by Twaddell, — the percentage of this is 13, and this divided by 10 gives 
 1*3 lb. = 1 lb. 5 oz. nearly of caustic potash to a gallon of the ley. The 
 stock ley should not be made stronger than this. 
 
 In the last column the boiling points of the solution at different 
 strengths are entered. These numbers are important, and explain to some 
 extent why boiling by steam is not so effective as by fire ; for the steam 
 heat, as was stated at page 6, is not higher than 210°, whereas the lowest 
 temperature noted in the table is 213°. 
 
 Potash, as used in the dye-house, as already seen from the analysis 
 given, is never chemically pure. Even when used as caustic it generally 
 contains lime and soda, and often chlorides and sulphides. Lime may be 
 detected by adding a little clear solution of bicarbonate of potash to a 
 clear solution of the potash, when its presence will be known by the 
 milkiness produced. It is not, however, detrimental to the dyer in the 
 operations in which potash is commonly used. Sulphides may be detected 
 by adding to a dilute solution of the potash some acetate of lead ; if 
 a sulphide is present, there will be a blackish precipitate. Sulphides are 
 destructive to gold ornaments on muslin and other cloths, for the metal 
 used is rarely pure ; commonly it is an alloy of gold with copper, &c. The 
 sulphides act upon all the inferior metals by contact, and destroy, or at 
 least blacken them. Potash containing sulphides should therefore be 
 avoided for goods having such ornaments. 
 
CHLORATE OF POTASH. 
 
 Caustic potash is evaporated to dryness, fused, and poured into 
 moulds to form it into small cylinders ; in this state it is sold by druggists 
 under the name of stick-potash. 
 
 Potash has a strong affinity for water, and deliquesces rapidly when 
 exposed to the air ; this property is also possessed by the carbonates. 
 
 Potassium combines with chlorine, and forms chloride of potassium — 
 technically termed muriate of potash ; which may be prepared by adding 
 hydrochloric acid to caustic potash, or its carbonate. It combines also 
 with iodine, and forms iodide of potassium (page 84) ; with bromine it 
 forms bromide of potassium ; and with sulphur it forms the sulphide of 
 of potassium. We have already noticed most of these salts. 
 
 Sulphate of Potash. — When sulphuric acid is added to potash it 
 forms a salt which has neither acid nor alkaline properties, and which is 
 easily crystallised. This neutral salt is produced abundantly in the manu- 
 facture of iodine. It is not deliquescent, and requires 15 times its own 
 weight of water to dissolve it. 
 
 Bisulphate of Potash. — This salt is obtained in the process of 
 making nitric acid from nitre, as two equivalents of acid are used; but it 
 may be prepared by adding to the sulphate half its weight of sulphuric 
 acid, and bringing the mixture up to a red heat in a porcelain or platinum 
 vessel. This salt has strong acid reactions, is very soluble in water, melts 
 easily with heat, and is exceedingly useful for dissolving metals, many of 
 which may be dissolved in it easily, although of very difficult solution in 
 the pure acid. 
 
 Sulphite of Potash is prepared by passing a current of sulphurous 
 acid gas through a solution of carbonate of potash till saturated. It 
 crystallises, and should be kept close, as it rapidly passes into the state of 
 sulphate by exposure to the air. 
 
 Nitrate of Potash may be prepared by saturating potash with nitric 
 acid ; but it is obtained abundantly in native beds (page 43). It is prepared 
 artificially in Germany and France, by forming large beds of animal and 
 vegetable refuse, in which decomposition is effected by putrefaction. 
 Potash is present in the organic matter, and these also yield nitrogen and 
 oxygen to form nitric acid ; and by combination the nitrate of potash is 
 formed. It is also largely prepared by mixing chloride of potassium with ' 
 nitrate of soda: a mutual exchange takes place, and there is formed 
 chloride of sodium and nitrate of potash, which is crystallised from the 
 solution of common salt. The chief uses of nitrate of potash are in the 
 manufacture of gunpowder and nitric acid. 
 
 Chlorate of Potash is prepared by passing chlorine gas through | 
 carbonate of potash. When the solution is saturated, crystals of this salt jj 
 
 
FERROCYANIDE OF POTASSIUM. 
 
 97 
 
 are formed (page 50). This salt, as already stated, is advantageously used 
 in several operations in the dye-house in which oxidation is required; also 
 with decoctions of some of the woods. When mixed with substances 
 containing carbon, it gives them great combustibility. Thus, if to a 
 mixture of chlorate of potash and sugar a drop of sulphuric acid is added, 
 combustion ensues, and the mixture burns with great rapidity. 
 
 Phosphate of Potash. — This salt is obtained by adding carbonate of 
 potash to a hot solution of phosphoric acid, until the solution ceases to 
 redden blue litmus paper. By careful evaporation, the salt may be 
 crystallised. 
 
 If the carbonate of potash be added to the phosphoric acid while 
 cold, in sufficient quantity to saturate it, the solution by evaporation gives 
 crystals of a salt having two proportions of acid — a biphosphate of potash. 
 
 Oxalate of Potash. — This salt is obtained by saturating carbonate 
 of potash with oxalic acid, and crystallising. In this state it contains one 
 equivalent of water. 
 
 The Binoxalate is obtained from wood sorrel, in which it exists ready 
 formed. It is obtained by reducing the expressed juice of the sorrel to 
 the consistence of a syrup, and setting it aside to crystallise. It is sold as 
 salt of sorrel and essential salt of lemons. The salt is acid to the taste ; it is 
 employed for removing ink stains and recently-formed iron moulds from 
 goods. Its crystals are composed of two equivalents of acid, one potash, 
 and two water. 
 
 Ferrocyanide of Potassium. — This salt is known as yellow prussiate 
 of^potash. We have already referred to the compound radical termed 
 cyano^eu, Cy, a nd #st'ated that it combines with other bodies, and forms 
 salts resembling the chlorides; it is found that two such salts combine 
 together and form a distinct compound. Thus, one proportion of cyanide 
 of silver will combine with one of cyanide of potassium, and forms a 
 double salt, AgCy-j-KCy; or take the protocyanide of iron = FeCy 2 , 
 it combines with four proportions of cyanide of potassium, = 4CyK, and 
 forms the ferrocyanide of potassium. This proportion of potassium may be 
 replaced by an equivalent proportion of another metal, but the iron and the 
 six equivalents of cyanogen maintain themselves together. It has, there- 
 fore, been inferred, that FeCy e is a distinct salt radical, which may be 
 termed ferroprussic acid; a theoretical deduction very interesting to study, 
 and which will be more fully developed as we proceed. The salts formed 
 by this radical or acid are distinguished by the prefix ferro. 
 
 The ferrocyanide of potassium, or prussiate of potash, is prepared on 
 the large scale by calcining together dried blood, hoofs, horns, hides, old 
 woollen rags, or similar materials, with carbonate of potash in an iron 
 vessel: commonly those substances are partially carbonised or burned in 
 large cast-iron cylinders previously to being mixed with the potash. If 
 
98 
 
 FERROCYANIDE OF POTASSIUM. 
 
 the animal matters are used without being subjected to this preliminary 
 process, they are mixed in the ratio of about 8 to 1 of pearl ash; but if 
 burned previously, one and a half of the charcoal is mixed with one of 
 pearl ash. When the animal matters are used without being charred, the 
 calcining pot is left open to allow the materials to be stirred and the 
 noxious vapours to escape after which the vessel is closed, and the heat 
 is increased. This is continued for some time, and at intervals of half an 
 hour the top of the vessel is uncovered for the purpose of stirring the 
 matter within. This process is continued until the flame ceases to rise 
 from the surface, and the materials are reduced to a red semi-fluid mass; 
 this generally takes place in about eight hours after the pot is closed. From 
 this description, the nature of the aetion may be easily understood. The 
 animal matters which contain nitrogen and carbon abundantly, are decom- 
 posed by the heat ; but, on account of the presence of the potash and iron 
 of the pot, definite portions of the carbon and nitrogen combine and form 
 cyanogen, which is simultaneously taken up by the potassium and iron ; 
 and we have four proportions of cyanide of potassium, with one propor- 
 tion of cyanide of iron, FeCy 2 . The molten mass is scooped out with 
 iron ladles, and allowed to cool. When the mass has cooled, it is dissolved 
 in cold water, and the solution is filtered through cloth. Lest any cyanide 
 of potassium should remain which had not received the necessary pro- 
 portion of iron obtained from the pot, sulphate of iron (copperas) is 
 added by degrees to the solution, so long as the Prussian blue which is 
 . formed on adding the iron salt is redissolved. The whole is then eva- 
 porated to a proper consistency; after which, pieces of coarse cord are 
 suspended throughout the liquid, upon which crystals of ferro-prussiate 
 are formed in regular bunches, and of a beautiful light citron yellow. 
 
 F errocyanide of potassium crystallises with three proportions of water, 
 which it loses at 212°. It dissolves in 4 parts of cold and 2 parts of 
 boiling water. From this salt all other ferrocyanides are derived as pre- 
 cipitates ; those of the metals are formed by adding a salt of the metal to a 
 solution of the prussiate. The following are the appearances of a few of 
 those precipitates, corresponding to the metals employed : — 
 
 Protoxide of manganese, 
 Peroxide of manganese, 
 „ ' lead, 
 
 „ iron, . 
 
 Protoxide of iron, 
 
 „ copper, . 
 
 „ zinc, 
 
 „ tin, 
 
 Peroxide of tin, 
 
 . White, turning to a deep red. 
 Greenish grey. 
 
 . White, with a yellowish hue. 
 
 . Deep blue. 
 
 . White, turning blue by exposure. 
 . Brown. 
 
 . White. 
 
 . White. 
 
 . Yellow. 
 
 Each of these precipitates is a ferrocyanide of the metal which 
 has taken the place of the potassium ; they are all insoluble in water, but 
 
FERROCYANIDE OF POTASSIUM. 
 
 99 
 
 where colour can be obtained from them, they are suitable for dyes, 
 although the colours dyed by the yellow prussiate are fugitive. Every 
 alkaline substance destroys them, and they are easily affected by soap and 
 by sunlight. 
 
 The principal use of the ferrocyanide salt in the dye-house is for 
 dyeing Prussian blue. To dye this colour, the goods are impregnated 
 with a persalt of iron, and then passed through a solution of yellow 
 prussiate of potash ; but this mode is objectionable for light shades and 
 light goods, as it causes much loss of the Prussian salt. The general 
 method of dyeing light Prussian blues upon cloths is, to put a little nitrate 
 of iron into the dye-tub filled with water ; the cloth is wrought in this for 
 about ten or fifteen minutes, and then washed two or three times in 
 clean water, to take off all the superfluous acid and iron. Whether the 
 cause of the retention of the iron be an attraction of the material of the 
 cloth for the iron, or the simple power of absorption by the fibres, we shall 
 not stay to examine here ; but although the nitrate of iron is an exceedingly 
 soluble salt, a portion of the peroxide of iron remains fixed in the fibre, 
 and this no washing will remove. The cloth, being well washed from the 
 | acid, is put into the prussiate. A small quantity of an acid must be added 
 I to the ferrocyanide of potassium solution, to take up the potassium, and 
 to set the ferrocyanogen at liberty, to unite with the iron upon the cloth, 
 which forms ferrocyanide of iron or Prussian blue, and constitutes the dye. 
 Care ought to be taken in adding acid to the prussiate, not to add more 
 than can be tasted, otherwise the colour is liable to change, becoming grey 
 or reddish when dried. 
 
 The following mode of adding sulphuric acid to the prussiate, when 
 a considerable quantity of goods is to be dyed at once, is sometimes 
 practised. What the dyer considers the proper quantity of yellow prussiate 
 of potash for the quantity of goods to be dyed, is dissolved in as much 
 boiling water as is necessary for solution. To. this solution a quantity of 
 Isulphuric acid is added, sufficient to make it strongly acid; and a portion 
 of the mixture thus prepared is added to the prussiate tub as required. 
 This method of adding the sulphuric acid is exceedingly objectionable, as 
 it causes loss by the evolution of cyanogen, which may be detected by 
 the pungent smell it excites ; and in proportion to the escape of that gas, 
 there is a loss of the dyeing power of the prussiate. If three parts of acid 
 jbe added to seven of yellow prussiate, the loss would amount to one-half, 
 and the remaining half would be so changed in its properties as to produce 
 only a bad blue. Thus the dyer must use an additional quantity of 
 prussiate, and after all he produces but an indifferent colour. 
 
 The proper method of using the acid is to dissolve the prussiate in 
 ihot water, and to add the necessary quantity of this solution to the water in 
 the tub in which the goods are to be dyed. Previous to putting in the cloth, 
 a few drops of sulphuric acid are added, just sufficient to be perceptible to 
 the taste ; or, what is a much better test, sufficient to redden blue litmus 
 iaper. The goods being wrought for some time in this mixture, they are 
 
100 
 
 FERRICY ANIDE OF POTASSIUM. 
 
 washed in clean water, having a small quantity of alum in solution. For 
 light shades of sky-blue, they should not be dried from the alum solution, 
 as there is a great tendency to assume a lavender hue. A better plan is 
 to employ two tubs of water, the one being touched with alum, and the 
 other pure, for washing from it. Cloths dyed by the prussiate should be 
 exposed to a very dry atmosphere when hung up to be dried. 
 
 Deep blue is dyed by passing the goods through strong nitrate of 
 iron, then through potash ley, which fixes a large quantity of the oxide of 
 iron upon the cloth washed, and then passed through the prussiate. 
 
 Royal blue is dyed by adding protochloride of tin ( salts of tin ) to the 
 nitrate of iron; entering the goods immediately, and passing them from 
 the iron through the prussiate without washing. This method gives a rich 
 deep blue, and is now much practised. Some of the peculiarities of the 
 process will hereafter be described; meantime, it will be sufficient to 
 observe, that a peculiar purple bloom is given, by using hydrochloric acid 
 in the prussiate solution instead of sulphuric acid. 
 
 Ferricyanide of Potassium. — This is technically called red prussiate 
 of potash. If a current of chlorine gas be passed through a strong solution 
 of yellow prussiate of potash, till the solution changes to a reddish colour, 
 and a drop of it added to nitrate or any persalt of iron gives no precipitate, 
 there is formed chloride of potassium, a salt differing materially from yellow 
 prussiate. The solution being evaporated, this salt is obtained in beautiful 
 ruby-red crystals, termed, from their colour, red prussiate of potash. 
 They are anhydrous, soluble in four parts of cold and a less quantity of 
 hot water. The red prussiate is well adapted for many operations in 
 dyeing. It yields the following colours with the salts of the different 
 metals undernamed : — 
 
 Bismuth, . ... Pale yellow. 
 
 Cadmium, 
 
 Cobalt, . 
 
 Copper, 
 
 Protosalts of iron, 
 Persalts of iron, 
 Manganese, 
 Mercury, 
 
 Nickel, . 
 
 Tin, 
 
 Zinc, 
 
 Yellow. 
 
 Dark -brown red. 
 Yellowish-green. 
 
 Deep blue. 
 
 No precipitate. 
 
 Brown. 
 
 Red-brown. 
 
 Yellow-green. 
 
 White. 
 
 Orange-yellow. 
 
 It will be observed by comparing this table with the one given above, 
 that the salts of iron, which yield a blue with yellow prussiate of potash, 
 give no colour with the red prussiate ; and the protosalts of iron, which 
 give only a grey with yellow prussiate, yield a deep blue with red prussiate. 
 
 The constitution of this salt, or rather the arrangement in which 
 these elements unite, is considered to be as follows — In the ferrocyani.de the 
 iron exists as a protocyanide, with the cyanide of another metal; but 
 
SODIUM. 
 
 101 
 
 in the ferricyanide we have iron as a percyanide, with cyanides of other 
 metals. Thus — 
 
 Ferrocyanide, FeCy 2 + 4CKy = Protocyanide. 
 
 Ferricyanide, Fe 2 Cy 6 + 6CyK = Percyanide. 
 
 Those who suppose that the compound FeCy 6 of the yellow prussiate 
 forms the salt radical of all the ferrocyanides, must also suppose that the 
 red prussiate has Fe 2 Cy 2 consisting of the same number of elements com- 
 bined together in double proportions, corresponding to the pro and per 
 oxides of iron. But whatever may be the true relation in which the 
 elements are united, the two salts are distinct in their reactions, and we 
 would suggest to the dyer to give particular attention to the difference of 
 the salts, with reference to salts of iron, as they are important, and will be 
 referred to hereafter. 
 
 Cyanide of Potassium. — If yellow prussiate be dried at a heat of 
 about 220^ to 300°, and eight parts of this dried salt be mixed with three 
 parts of dry carbonate of potash, and the mixture put into a crucible and 
 kept fused until effervescence ceases, then removed from the fire, and 
 allowed to settle for a few minutes : on pouring off the clear into an iron 
 vessel, it solidifies into a white crystalline mass, which is cyanide of 
 potassium = CyK. This salt has a strong alkaline reaction, and is 
 peculiar for its power of dissolving metals and giving precipitates which 
 might be advantageously applied to some of the operations of dyeing. 
 
 Cyanate of Potash.— This salt is prepared in the same way as the 
 last, but with the addition of some oxide of manganese, or other oxide ? 
 which converts the cyanogen into cyanic acid, and forms cyanate of potash 
 = CyK 2 0. The cyanates of the alkalies are all soluble in water, and in 
 this they differ from the cyanates of the other metals. 
 
 Sodium (Na 23). 
 
 Soda was not distinguished from potash till near the middle of the 
 eighteenth century, when their distinctive characters were recognised. 
 The potash was termed the vegetable, and the soda the mineral alkali. 
 In 1807, Sir H. Davy demonstrated that soda, like potash, is the oxide of a 
 metal which he named sodium. It is a white metal, having much the ap- 
 pearance of silver, but is sufficiently soft to yield to the pressure of the 
 fingers, and to be cut by the nail. It oxidises spontaneously in the air, 
 but not so rapidly as potassium. When a small piece is thrown upon 
 water, it floats ; the heat, generated by combining with the oxygen of the 
 water, melts it, and it forms a silvery globe, which gyrates rapidly on the 
 surface of the water ; but it does not inflame the hydrogen unless it be 
 kept stationary, and then an explosion takes place. If, however, the 
 temperature of the water is as high as 110° Fah., the hydrogen burns as 
 it is evolved, with a bright yellow flame. In this experiment oxide of 
 sodium is formed and dissolved in the water, which thus becomes a solu- 
 
102 
 
 SODA. 
 
 tion of caustic soda. Sodium is a very abundant element in Nature, but is 
 always found in combination — e.g ., as nitrate or carbonate of soda and 
 chloride of sodium (common salt). This latter is the great source for soda 
 manufacturing purposes and since the process of making soda from it was 
 discovered. Soda, owing to its cheapness, has been used instead of potash 
 in almost all the processes of the arts that admit of the substitution. 
 
 Soda, as sold to dyers and bleachers, is in the state of a dry white 
 powder, or granular substance, termed soda-ash, which is an impure car- 
 bonate, prepared as follows: — A quantity of about 600 lbs. of common salt 
 is put upon the bottom of a reverberatory furnace, previously heated ; upon 
 this is let down, from an apparatus on the roof of the furnace, a quantity 
 of sulphuric acid, of the specific gravity 1*600 ; and the salt is decomposed. 
 
 The result is as follows : — 
 
 ( ci« 
 
 Tlyrlrnnhlnri'n a^id 
 
 Common salt,.. 1 ^ 
 
 ( Na 2 ..^^ ^ 
 
 ( H 2 ...^^ 
 Sulphuric acid, | c-q 
 
 Sulphate of soda. 
 
 The hydrochloric acid passes off with the steam occasioned by the dilute 
 sulphuric acid. This operation, during which the materials require to be 
 stirred occasionally, lasts about four hours: the charge is then withdrawn 
 from the furnace. The sulphate of soda thus prepared is reduced to 
 powder, and mixed with an equal weight of ground chalk, and half its 
 weight of coal, well ground and sifted. This mixture is introduced into a 
 very hot reverberatory furnace, about two hundredweights at a time, and is 
 frequently stirred until it is uniformly heated. In about an hour it fuses ; 
 it is then well stirred for about five minutes, and drawn out with a rake 
 into a cast-iron trough, in which it is allowed to cool and solidify. This is 
 called ball soda, or British barilla, and contains about 22 per cent, of 
 alkali. To separate the salts from insoluble matter, the cake of ball soda, 
 when cold, is broken up, put into vats, and covered with warm water. In 
 six hours the solution is drawn off from below, and the washing repeated 
 about eight times, to extract all the soluble matter. These liquors being 
 mixed together, are boiled down to dryness, and afford a mixture of salts 
 of extraordinary composition. The analyses of two samples will give the 
 reader some idea of their character : — 
 
 Carbonate of soda, 
 
 68*907 
 
 65*513 
 
 Caustic soda, 
 
 14*433 
 
 16*072 
 
 Sulphate of soda, 
 
 7*018 
 
 7*813 
 
 Sulphite of soda, 
 
 2*231 
 
 2*134 
 
 Hyposulphate of soda, 
 
 trace. 
 
 trace. 
 
 Aluminate of soda, . 
 
 1*016 
 
 1*232 
 
 Silicate of soda, 
 
 1*030 
 
 0*802 
 
 Chloride of sodium, . 
 
 3*972 
 
 3*860 
 
 Sulphide of sodium, . 
 
 1*314 
 
 1*542 
 
 Insoluble matters, 
 
 0*814 
 
 0*974 
 
 
 100*735 
 
 99*942 
 
SODA MADE DIRECT FROM COMMON SALT. 
 
 103 
 
 For the purpose of getting rid of the sulphur and carbonating the soda, 
 the salt is now mixed with one-fourth of its bulk of sawdust, and exposed 
 to a low red heat in another reverberatory furnace for about four hours, 
 which converts the caustic soda into carbonate, while the sulphur is carried 
 off. This product, if the process is well conducted, contains about 50 per 
 cent, of alkali, and forms the soda-ash of the best quality. When it is to 
 be converted into crystallised carbonate of soda, it is dissolved in water, 
 allowed to settle, and the clear liquid boiled down until a pellicle appears 
 on its surface. The solution is then run into shallow boxes of cast iron to 
 crystallise in a cool place, and after standing for a week the mother liquor 
 is drawn off, and the crystals drained and broken up for the market. This 
 mother liquor is evaporated to dryness, and yields a very impure soda-ash, 
 containing about 30 per cent, of alkali, which is often employed for making 
 soap. 
 
 The common crystallised carbonate of soda of the shops is very pure. 
 The crystals contain ten equivalents of water. When exposed to the air, 
 these crystals lose a portion of their water, and assume a chalky white 
 appearance ; if they are subjected to heat, they dissolve in their water of 
 crystallisation. We have known of these crystals being used for the opera- 
 tions of bleaching merely dissolved ; but they are neither well nor profitably 
 used in that way. 
 
 They contain in 100 parts by weight 
 
 Caustic soda, 
 
 21*81 
 
 Carbonic acid, . 
 
 15*43 
 
 Water, .... 
 
 62*76 
 
 
 100*00 
 
 Thus fully more than three-fifths of their weight is water. 
 
 The dry carbonate of soda of the shops, so much used for domestic 
 purposes, is the same as the crystallised soda deprived of its water of 
 crystallisation. 
 
 Soda made direct from Common Salt. — Some years ago, a patent 
 was taken out by Hemmings and Dyar for making carbonate of soda direct 
 from common salt by the mutual decomposition of carbonate of ammonia 
 and chloride of sodium ; but from certain practical defects in the process 
 it was not commercially successful. Several manufacturers endeavoured 
 to overcome these defects by certain forms of apparatus, but without that 
 success that warranted them giving up the old process for the new, 
 although, looking at it theoretically, it was perfect and beautiful. 
 
 Lately, Mr. James Young, of Kelly, has proposed such improvements 
 in the apparatus for carrying out this new process that give hopes of suc- 
 cess, a description of which will enable the reader to understand both the 
 theory and practice of the process. Into an air-tight boiler there is put a 
 solution of chloride of ammonium (sal-ammoniac) and a quantity of finely 
 ground chalk or carbonate of lime, and the solution brought to boil, when 
 
SODA-ASH. 
 
 101 
 
 a mutual transfer takes place between the chalk and the ammonium 
 chloride ; the chlorine of the latter combines with the calcium of the chalk, 
 forming chloride of calcium, and the ammonium and carbonic acid unite 
 and form carbonate of ammonium, which, being volatile at a boiling heat, 
 passes off with a little steam. Thus — 
 
 Chloride of ammonium 
 Chalk 
 
 { 
 
 { 
 
 Ammonium.. 
 
 Chlorine - 
 
 Carbonic acid 
 Calcium 
 
 As gas. 
 
 In solution. 
 
 This gaseous earbonate is conducted by a pipe into a second air-tight 
 boiler, containing a saturated solution of chloride of sodium (common 
 salt), giving rise to another double decomposition. The chlorine of the 
 chloride of sodium combines with the ammonium of the carbonate, and the 
 sodium combines with the carbonic acid. Thus — 
 
 Carbonate of am- 
 monium 
 
 Chloride of sodium 
 
 { 
 
 { 
 
 Ammonium . . . 
 Carbonic acid 
 
 Chlorine 
 
 Sodium 
 
 Ammonium 
 
 chloride. 
 
 Sodium carbonate. 
 
 Both these salts remain in solution. There is now passed through this 
 solution a current of carbonic acid gas, an equivalent of which unites with 
 the carbonate of soda and forms a bicarbonate which requires a much larger 
 quantity of water to dissolve it than is present; it consequently separates 
 from the water as a crystalline precipitate, leaving the chloride of ammonium 
 in solution with a small quantity of bicarbonate of soda ; this solution is run 
 off into another air-tight boiler to be treated with chalk as at first, when 
 the same reactions take place as above described. Water is now let into 
 the boiler containing the bicarbonate of soda and brought to boil, which 
 drives off the second equivalent of carbonic acid, leaving a solution of pure 
 carbonate of soda, which is run from the boiler, and may be crystallised as 
 washing soda or evaporated to dryness, forming pure carbonate of soda. 
 It will be observed from this description that the ammonium salt is used 
 over and over again, and it was the loss of this salt during the process that 
 has hitherto prevented its success. Mr. Young has avoided this source of 
 loss by having three air-tight boilers all connected together by pipes and 
 stopcocks, and effects all the decompositions in the liquid state; there is 
 no exposure until the operations are completed. The carbonic acid driven 
 off from the bicarbonate being led into the mixed solutions of carbonate of 
 soda and chloride of ammonium, everything is utilised. The adoption of 
 such a process would put into the hands of the dyer a pure carbonate of 
 soda, which for many operations in the art would be of great benefit. 
 
 Soda - Ash. — Owing to various circumstances attending the manu- 
 
SODA-ASH. 
 
 105 
 
 facture of this salt, its percentage is very uncertain, varying from 40 to 50 
 per cent., and it is, therefore, generally priced according to its percentage. 
 The percentage may be determined by some such means as we have 
 described for bleaching powder, that is, by having an acid exactly of the 
 strength at which 100 measures of it will saturate 100 grains of caustic 
 soda. To form the test acid, according to the late Professor Graham’s 
 directions, 4 ounces avoirdupois of oil of vitriol are diluted with 20 ounces 
 of water, or larger portions of acid and water may be mixed in these pro- 
 portions. About three-fourths of an ounce of bicarbonate of soda is 
 heated strongly by a lamp for a few minutes to obtain pure carbonate of 
 soda (or what will do for ordinary purposes of the dye-house, take some 
 crystals of soda and dry in a basin until all water is given off ; when boil- 
 ing has ceased, bring the heat to about a dull red, this will give the soda 
 salt), of which 171 grains are immediately weighed, this quantity contains 
 100 grains of soda ; it is dissolved in 4 or 5 ounces of water, and the alkali- 
 meter is filled up to the highest graduation with the dilute acid. The acid is 
 poured gradually into the soda solution till the action of the latter upon litmus 
 test-paper ceases to be alkaline and becomes distinctly acid, then the mea- 
 sures of acid necessary to produce that change are accurately observed. Say 
 it requires 90 measures : a plain cylindrical jar, of which the capacity is 
 about a pint and a half, is graduated into 100 parts, each containing 100 grain 
 measures of water, or ten times as much as the divisions of the alkalimeter. 
 This jar is filled up with the dilute acid to the extent of 90, or whatever num- 
 ber of the alkalimeter divisions of acid were found to neutralise 100 grains 
 of soda, and water is added to make up the acid liquid to 100 measures. 
 This forms a test acid of which 100 measures neutralise and are equivalent 
 to 100 grains of soda, or one measure of acid to one grain of caustic soda. 
 This acid ought to be kept in a well-stoppered bottle. By a curious 
 coincidence, strong oil of vitriol diluted with eleven times its weight of 
 water, gives this test acid exactly ; but, as oil of vitriol varies a little in 
 strength, it is better to form the test acid in the manner described, than to 
 trust to that mixture. Twenty-one measures of the test acid should 
 neutralise 100 grains of crystallised carbonate of soda, and 58-5 measures 
 of it should neutralise 100 grains of pure anhydrous carbonate of soda. 
 
 To test a sample of soda-ash, 100 grains are weighed and dissolved in 
 two or three ounces of hot water. The alkalimeter is filled with the test 
 acid, which is gently poured into this solution, stirring, as each drop is 
 added, until a piece of blue litmus-paper, which may be kept in contact 
 with the liquor, is turned red. The number of graduations taken to effect 
 this indicates the percentage of caustic alkali in the sample. 
 
 Another method of using test acid is by weight. The acid is made of 
 such a strength as one or two grains by weight will exactly neutralise one 
 grain of pure alkali. The vessel commonly used for this purpose is of the 
 annexed form, but any convenient vessel will do. It is filled with the test 
 acid, and the whole correctly weighed. The acid is then dropped from 
 the small orifice into a weighed quantity of the carbonate until a neutral 
 
106 
 
 SODA-ASH. 
 
 sulphate is produced, indicated as above by test-paper. The bottle with 
 its contents is then again weighed; the loss 
 of weight gives, by calculation, the quantity 
 of real alkali in the sample. Say that every two 
 grains of the test acid are equivalent to one 
 grain of pure soda, and that twenty-five grains 
 of soda-ash require twenty grains of acid to 
 neutralise it, the real alkali present will be ten. 
 Now 25 being the fourth of 100, the 10 is multi- 
 plied by 4, giving 40 as the percentage of the sample. This method of 
 testing carbonated alkalies, provided the operator has a good balance, is 
 very correct and simple. 
 
 An indirect method is sometimes recommended, thus : — Take a small 
 flask and a test-tube that can be put inside, and stand nearly upright. Fifty 
 grains of the soda-ash are dissolved in a little water in the flask, and the 
 tube, which is nearly filled with dilute sulphuric acid, is carefully placed in 
 the position shewn in the figure. A small chloride of calcium tube is fitted 
 into the mouth of the flask, and the whole is then 
 carefully weighed; after which, by holding the 
 flask a little on one side, the acid is poured from 
 the tube into the soda solution. This should be 
 done gradually, that the effervescence may not be 
 too violent. When all effervescence ceases, and 
 the flask is well shaken, the cork is taken out, 
 that the rest of the carbonic acid may freely 
 escape ; it is then put back, and the flask is again 
 weighed : the loss of weight will of course indicate the loss of carbonic 
 acid, and by this the quantity of soda present may be calculated. If the 
 loss of weight be 10 grains, then as 44, the equivalent of carbonic acid, is 
 to 62, that of soda, so is 10 to 14-09, which, being multiplied by 2, there 
 being only 50 grains of soda used, gives 28-18 as the percentage of alkali 
 in the sample. This method, however, is not much to be relied upon in 
 testing the value of soda-ash, as it takes no cognisance of caustic soda 
 present ; it is a very good method, however, for taking the quantity of car- 
 bonic acid present in soda or other carbonates. 
 
 The following analyses shew the composition of 
 common soda-ash and refined soda-ash : — 
 
 Soda-Ash. 
 
 what is termed 
 Refined-Ash. 
 
 Chloride of sodium (common salt), 
 
 3-665 
 
 3-310 
 
 Sulphate of soda, .... 
 
 9-676 
 
 10-012 
 
 Carbonate of soda, .... 
 
 72-037 
 
 84-517 
 
 Caustic soda, 
 
 12-181 
 
 0-280 
 
 Aluminate of soda, .... 
 
 0-828 
 
 0-474 
 
 Silicate of soda, 
 
 1-014 
 
 0-366 
 
 Insoluble matter, 
 
 0-390 
 
 0-374 
 
 99-791 99-333 
 
SODA-ASH. 
 
 107 
 
 From these analyses it will be seen that the carbonic acid process for 
 testing the value of soda-ash as a bleaching or dyeing agent is not good ; 
 but it may be adopted when other means are not at hand for the crystal- 
 lised soda, or what is termed washing soda. There are several other 
 methods and forms of apparatus for testing the value of soda-ash, all based 
 however upon the principles here detailed of neutralising the alkali with a 
 standard strength of acid. 
 
 We may observe that the same principle applies to potash as to 
 soda. The test acid is obtained of such strength that one graduation will 
 be equal to one grain of potash, which will be found in the same way as 
 for soda, namely, by neutralising a known weight of pure dry carbonate of 
 potash. 
 
 Where both alkalies are used there is prepared a test acid, which does 
 for either soda or potash. Prepare pure anhydrous carbonate of soda as 
 described for the soda test ; weigh 106 grains, which is an equivalent, and 
 dissolve it in water, then take dilute acid in the alkalimeter, and add it to the 
 soda until it is perfectly neutral ; mark the number of graduations it takes 
 for this : say it takes 60 ; then to every 60 graduations of the acid left add 
 40 of water, and thus we have a stock acid, of which 100 graduations is 
 equal to an equivalent of either alkali. Thus, 
 
 100 graduations is equal to 62 grains caustic soda, 
 
 94 potash. 
 
 To test by this method, take 100 graduations of the test acid, and weigh 
 200 grains of the alkali, and dissolve in 200 measures of water ; add this 
 solution to the acid till it is neutralised, and mark how many measures 
 have been necessary to effect this ; then the percentage of alkali is easily 
 calculated. Say that 140 measures of the alkali solution have been necessary 
 to neutralise the acid; if the alkali is soda, then the 140 grains of soda-ash 
 will contain 62 grains of caustic soda; and the percentage is found by the 
 following calculation : — 
 
 140 : 62 : : 100 : 44'29 per cent. 
 
 If the alkali is carbonate of potash, the 140 grains will contain 47 *2 grains 
 of caustic potash ; and then the percentage is found by the proportion : — 
 
 140 : 94 : : 100 : 67T4 per cent. 
 
 Care should be taken that the test acid when used is always of the same 
 temperature, as the bulk varies by heat. 
 
 It may be observed that the acid test for soda, derived from a coinci- 
 dent in their equivalents, will serve equally, in ordinary circumstances, 
 for potash, each graduation indicating 1 of caustic soda, and 1£ of 
 potash. 
 
108 
 
 SODA-ASH. 
 
 The process for making caustic soda from soda-ash is the same as 
 described for making caustic potash, namely, a quantity of ash is boiled, 
 and, when boiling, slaked lime is added until a small portion taken out 
 does not effervesce on adding an acid ; but the equivalent of soda being 
 less than that of potash, it requires more lime for a given weight. 
 
 The following table, constructed by Dr. Dalton, will be found useful 
 to the bleacher, shewing the quantity of caustic soda in his solutions, 
 indicated by the hydrometer : — 
 
 Specific 
 
 Gravity. 
 
 Alkali per 
 cent. 
 
 Twaddell’s 
 
 Hydr@meter. 
 
 Specific 
 
 Gravity. 
 
 Alkali per 
 cent. 
 
 Twaddell’8 
 
 Hydrometer. 
 
 2-00 
 
 77-8 
 
 200 
 
 1*40 
 
 29-0 
 
 80 
 
 1-85 
 
 63-6 
 
 170 
 
 1-36 
 
 26-0 
 
 72 
 
 1-72 
 
 53 -8 
 
 144 
 
 1-32 
 
 23-0 
 
 64 
 
 1-63 
 
 46-6 
 
 126 
 
 1-29 
 
 19-0 
 
 58 
 
 1-56 
 
 41-2 
 
 112 
 
 1-23 
 
 16*0 
 
 46 
 
 1*50 
 
 36-8 
 
 100 
 
 1-18 
 
 13-0 
 
 36 
 
 1*47 
 
 34-0 
 
 94 
 
 1-12 
 
 9-0 
 
 24 
 
 T44 
 
 31-0 
 
 88 
 
 1-06 
 
 4-7 
 
 12 1 
 
 The remarks (page 95) in reference to the presence of sulphides in 
 potash -ley injuring the gold ornaments of light muslins, &e., are equally 
 applicable here ; and the same tests for ascertaining the presence of these 
 impurities in potash may be employed to detect their presence in soda 
 solutions. With respect to the solubility of soda — 
 
 100 parts water at 
 
 62° 
 
 Fah. dissolve 41 parts of caustic soda. 
 
 100 
 
 90° 
 
 
 46 
 
 100 
 
 131° 
 
 
 64 
 
 100 
 
 158* 
 
 
 72 
 
 100 
 
 176° 
 
 5* 
 
 78 
 
 Cold water saturated with soda, and brought to boil, attains a tem- 
 perature of 266° Fah. 
 
 Crystallised carbonate of soda dissolves in water in the following 
 proportions and temperatures, as given in Chemical Technology by Rich- 
 ardson and Watts — 
 
 100 parts water at 57° Fah. dissolves 60 parts of soda crystals. 
 
 100 „ 97° „ 133 „ 
 
 100 „ 100° „ 1666 „ 
 
 100 „ 219° „ 445 
 
 This table shews the importance of attention being paid to the temperature 
 of the water in dissolving this salt. 
 
 The salts of soda are in general the same in their chemical characters 
 as the corresponding salts of potash, and form cyanides, prussiates, and 
 
PHOSPHATE OF SODA. 
 
 109 
 
 chromates ; but they are not so generally used, on account, perhaps, of the 
 disposition which almost all soda salts have to effloresce when exposed to 
 the air. 
 
 Sulphate of Soda. — Soda, saturated with sulphuric acid, forms 
 sulphate of soda, which crystallises easily, and is known by the name of 
 Glauber Salts. An impure sulphate of soda is sold under the name of 
 salt cake , obtained in making hydrochloric acid. It always contains com- 
 mon salt. A purer sort of salt cake is obtained by the makers of nitric 
 acid, or in the making of vitriol where nitrate of soda is acted upon by 
 sulphuric acid, the product being valuable, considerable care is taken to 
 have the nitrate decomposed; salt cake from this source contains an excess 
 of sulphuric acid. By heating this in a furnace, to drive off excess of acid, 
 or neutralising with carbonate of soda, and crystallising, there is obtained 
 Glauber salts, which are used in calico-printing. 
 
 Chloride of Sodium. — Hydrochloric acid, added to soda, forms 
 hydrochlorate of soda; in the language of the dye-house (muriate of 
 soda), common salt, properly chloride of sodium. The action is as 
 follows : — 
 
 Soda, 
 
 Hydrochloric acid, 
 
 Chloride sodium. 
 
 Water. 
 
 This salt is sometimes made artificially to be used with nitric acid to 
 make the aqua regia for dissolving tin. It is often amusing to see the care 
 taken to mix the acid and the soda to form what may be got so conveniently 
 as common salt. 
 
 Nitrate of Soda. — Nitric acid added to soda forms nitrate of soda. 
 This salt, as already stated (page 43), is found abundantly in Nature, and 
 is termed cubic nitre, from the shape of its crystals, and to distinguish it 
 from nitrate of potash (nitre). When heated to redness it is decomposed, 
 and gives off much oxygen gas ; it is often employed for this purpose, and 
 for oxidising metals in a fused state. It is also occasionally used along with 
 hydrochloric acid for preparing some of the salts of tin for mordants. 
 
 Borate of Soda. — Boracic acid with soda forms borate of soda 
 (borax or tinkal). This, as we have before noticed (under Boron), is also 
 a natural product ; it is used as a blowpipe re-agent for fluxing metals. 
 
 Phosphate of Soda. — Phosphoric acid with soda forms phosphate of 
 soda, also a useful salt as a test for the presence of magnesia in water 
 solutions. 
 
 Soda, on account of its cheapness, has been substituted for potash in 
 the manufacture of some of the salts most extensively used, such as ferro- 
 
110 
 
 SOAP. 
 
 cyanides, chromates, alum, &c., but none of these modified salts have come 
 into common use, not that they are less suitable in the dye-house, but for 
 other reasons, which we indicated above. 
 
 Lithium. (L 7.) 
 
 This is another alkaline metal, the oxide of which is termed lithia. 
 It has properties somewhat resembling those of soda and potash, and 
 combines with acids as a base in the same manner as these other alkalies. 
 It is, however, very rare, and only got in small quantities, from a mineral 
 termed Lepidolite. It has not as yet been used in any process of manu- 
 facture, so far as known to us, and therefore we pass it without further 
 consideration. 
 
 Soap. 
 
 In connection with the alkalies, it will be necessary to direct attention 
 to Soap , an article of great importance in the dye-house. If we take a 
 quantity of oil, and add to it some caustic alkali, a milk-white solution is 
 obtained, which is found to be soluble in water. This solution boiled 
 down to a proper consistence, and cooled, forms soap. All sorts of fats and 
 oils are used in soapmaking ; they all contain certain acids capable of 
 combining with the alkali, and giving a detersive character to the com- 
 pound, Soap may be considered as a salt. The soap made with soda is 
 hard, that with potash soft ; and the degree of hardness, in either case, 
 varies according to the nature of the oil or fat employed. In manu- 
 facturing soap, care is taken to obtain a proper mixture of these fats 
 and oils, so as to produce a soap of proper consistence. We quote from 
 an article by the late Professor Crace Calvert, upon different soaps made 
 and used by dyers and calico-printers. 
 
 “It is easy to understand that a great variety of soaps must be 
 manufactured to suit the various purposes to which soaps are applied 
 in domestic and manufacturing concerns, and so we find that different 
 qualities of soap are manufactured for boiling silks, clearing wool, or 
 for clearing madder goods, and giving to the different colours obtained 
 from this root a greater brilliancy and fixity. I have thought that it might 
 be interesting if I were to offer a statement of the results I have obtained in 
 connection with this point. To arrive at a medium , shewing the real difference 
 which exists between soaps employed for the above purposes, I have been 
 obliged to make a great number of analyses. This will be easily under- 
 stood if we reflect that the quality of the soaps used by different parties in 
 a given trade, is so little examined, that even the soap used by a single firm 
 varies as much as 25 per cent, in quality. The following general results I 
 have, however, arrived at in calculating the composition of these soaps as 
 containing 30 per cent, of water: — 
 
SOAP. 
 
 Ill 
 
 Composition of Soaps, per 1,000 Parts. 
 
 
 Calico Printers’ 
 
 Silk Dyers’ 
 
 Wool Scourers’ 
 
 
 Soap. 
 
 Soap. 
 
 Soap. 
 
 Fatty matters,... 
 
 640 
 
 619 
 
 614 
 
 Soda, 
 
 60 
 
 81 
 
 86 
 
 Water, — 
 
 300 
 
 300 
 
 300 
 
 
 1000 
 
 1000 
 
 1000 
 
 From these results we find that the soaps employed vary in the quantity of 
 alkali, according to the nature of their application ; thus, in 1,000 parts of 
 soap there are 21 parts more alkali in the one used for boiling silk, and 26 
 parts more alkali in that employed for clearing wools, than there are in the 
 soaps best suited for clearing madder purples. These facts shew us at 
 once how important it is to inquire into the real composition of a soap 
 before employing it for a given purpose. If, on the one hand, a calico- 
 printer were to use a soap which had the composition of the one used by 
 the wool-scourer, he would cause to fade the shade of his madder purples ; 
 and if, on the other hand, the wool-scourer were to employ the neutral 
 soap of the calico-printer, he would have but imperfect results, owing to 
 this circumstance, that in the latter case an excess of alkali is essential, 
 not that the alkali may combine with the fatty matters of the wool, but 
 that it may form an emulsion with the stearine and elaerine discovered 
 by M. Chevreul, and thus liberate the dirt which they fix on the wool. 
 There is another point which deserves the serious attention of calico-printers, 
 and that is, the influence which soaps of different compositions must have 
 on the different shades obtained in madder dyeing ; for it must be obvious 
 that the soap containing a slight excess of alkali, which is the best suited 
 for clearing madder reds or dark pinks, would deteriorate the beauty of the 
 madder purples. In the first case, the dyer has in view, not only to 
 fix and brighten his reds or pinks, but further to remove the yellow 
 colouring matter, and also partially the red ; whilst in the latter a soap 
 containing as little alkali as possible appears to me to give the best results. 
 I have found by experiment the two following soaps to be best suited for 
 these purposes : — 
 
 Soap for Purples. Soap for Dark Pinks. 
 
 Fatty matter, 604 59*23 
 
 Soda, 5*6 6*77 
 
 Water, 34*0 34*00 
 
 100*0 100*00 
 
 Still we find that calico-printers in general employ the same quality of 
 soap for all shades of madder goods. Some dyers think that they over- 
 
112 
 
 SOAP. 
 
 come this difficulty by employing less or more of the same soap ; but this 
 is an error, not only manifested by the above remarks, but because, as 
 we shall shew presently, the different soaps sold in the market offer in 
 their relative composition the differences which are equal to the different 
 proportions they are in the habit of using for given styles or shades of 
 madder prints. This fact can be easily proved by examining the qualities 
 of soap which are supplied to a firm during a period of twelve months ; 
 for we find, as the following results shew, that the quality of soap some- 
 times varies as much as 25 per cent, in value : — 
 
 
 No. 1. 
 
 No. 2. 
 
 No. 3. 
 
 No. 4. 
 
 No. 5. 
 
 Water, 
 
 26-00 
 
 29-3 
 
 34*81 
 
 38-0 
 
 46-00 
 
 Fatty matter, 
 
 66-00 
 
 64-0 
 
 56-00 
 
 55-4 
 
 46-01 
 
 Alkalies, 
 
 7-56 
 
 6-3 
 
 6-98 
 
 6-1 
 
 5-80 
 
 Impurities, 
 
 0-43 
 
 0-4 
 
 2-21 
 
 0-5 
 
 2-19 
 
 
 99-99 
 
 100-0 
 
 100-00 
 
 100-0 
 
 100-00 
 
 The figures also shew that the quantity of the really effective agent — viz. 
 the fatty matter — in a soap can vary from 46 to 66 per cent; consequently 
 it may be seen that a large sum of money is wasted by some of our large 
 firms annnally, for want of paying proper attention to one single article. 
 It must be remembered that each piece of madder-dyed goods requires 
 from 1 ounce to 4 ounces of soap to clear it. If we take the average at 
 2 ounces per piece, and admit that a print-work produces 100,000 pieces 
 per annum, the quantity of soap used would be 12,500 lbs. ; and if the soap 
 be 25 per cent, under value, the loss would equal 4,125 lbs. 
 
 “ There is another fact connected with the use of soap by calico-printers 
 which deserves most serious consideration, and to which attention has not, 
 so far as I am aware, been drawn — viz., that soaps are not at the present 
 day, as formerly, made with one kind of fatty matter, but are manufactured 
 sometimes from palm oil, at other times with vegetable fluid oils, such as 
 rapeseed oil, Gallipoli oil, again with animal fatty matters, and lastly with 
 the oily liquid called oleine, which is obtained when solid fatty matters 
 are submitted to pressure to obtain a fatty matter, having a higher fusing 
 point, and consequently more fit for the manufacture of composite candles. 
 The liquid oleine, containing small amounts of margarine and stearine, is 
 extensively employed at the present day in the manufacture of soaps. I 
 have ascertained from direct experiment, that such a soap will not give the 
 same brilliancy and fixity of colour to the shades obtained from madder 
 roots, as a soap made with a vegetable oil, composed of margarine and 
 oleine, or with an animal fatty matter, composed of margarine, stearine, 
 and oleine ; consequently, if a dyer uses a soap of the former composition, 
 it will prove, if not a direct loss to him, at least an injury to his goods, in 
 
SOAP. 
 
 113 
 
 disabling him from producing the maximum effect. I should also mention 
 here, that I have found in print-works household soap of an inferior 
 quality, and containing 10 per cent, and upwards of resins. These soaps 
 have none of the properties required in calico-printing, and must, therefore, 
 prove a loss to the printer, as well as those soaps which are sometimes 
 found to contain glue. I hope these facts will prove how highly desirable 
 it is, that with the existing competition, both amongst our local firms, and 
 those of the continent, the indifference which exists as to the qualities of 
 the drugs employed in print-works should cease, and that science, united 
 with practical knowledge, should step in and guide the application of 
 chemical art in manufactures. Then, and then only, will our manufacturers 
 progress in a sound and remunerative manner. 
 
 “ I have also examined a great variety of soaps employed for domestic 
 purposes, and have found their qualities to vary materially, as the figures 
 underneath shew: — 
 
 
 Hard Soap. 
 
 Soft Soap. 
 
 No. 1. 
 
 No. 2. 
 
 No. 3. 
 
 No. 1. 
 
 No. 2. 
 
 Fatty matters, &c., .... 
 
 67-00 
 
 57-52 
 
 56-09 
 
 41-67 
 
 58-95 
 
 Water, 
 
 26-81 
 
 36-00 
 
 39-14 
 
 49-49 
 
 32-15 
 
 Alkali, 
 
 6-19 
 
 6-48 
 
 4-77 
 
 8-84 
 
 8-90 
 
 
 100-00 
 
 100-00 
 
 100-00 
 
 100-00 
 
 100-00 ” 
 
 The quantity of water in soap may be ascertained by taking 100 grains 
 of the sample in thin parings, putting them into a water bath or oven, of 
 which the heat does not exceed 212°, and allowing them to stand as long 
 as they continue to lose weight, which is known by occasional weighing ; 
 the loss of weight indicates the water evaporated. 
 
 The other impurities in soap may be detected by dissolving 100 grains 
 in strong alcohol, and applying a gentle heat ; the soap is thus dissolved 
 and the impurities remain insoluble. The best soap should not contain 
 above one per cent, of matter insoluble in alcohol. Good soap may be 
 known by its comparative transparency. When cut thin, the purer the 
 soap is, the more translucent. Dry soap is also more transparent than moist. 
 
 The earths combine also with fats and form soaps, some of which are 
 sparingly soluble in water, so if there be oil or grease upon goods, and 
 they are put into water or other liquid containing earths which form an 
 insoluble or sparingly soluble soap, these will be so many white stains in 
 the dyed goods; when ordinary soap is put into water that has earthy 
 salts in it, such as carbonate or sulphate of lime, these salts are decom- 
 posed by the alkali of the soap taking the acid of the salt, and greasy or 
 
 H 
 
114 
 
 SOAP. 
 
 insoluble soapy spots are produced. This is often experienced when 
 washing with soap in hard water: these spots are sources of annoyance to 
 the dyer. 
 
 When soap is dissolved in water there should be no oily or fatty 
 matters visible 'On the surface — this would indicate that too little alkali 
 had been used in the manufacture of the soap. The following method of 
 testing the quality of soaps is given by M. Dumas, in the Chemie Applique'e 
 aux Arts , tome vi : — 
 
 “ To determine the quantity of water, thin slices are cut from the 
 edges and from the centre of the bars. A portion is then weighed, about 
 60 to 70 grains, and exposed to a current of air, heated to 212° Fah., or 
 in an oil-bath until it ceases to lose weight. The dry substance is then 
 weighed ; the difference between the first and last weighing will indicate 
 the quantity of water evaporated. If it be a soft soap it is weighed in a 
 counterpoised shallow capsule. In good soap the amount of water varies 
 from 30 to 45 per cent., in mottled and soft soaps, from 36 to 52 per 
 cent. 
 
 “ The purity of soap may be ascertained by treating it with hot 
 alcohol; if the soap be white, and without admixture, the portion 
 remaining undissolved is very minute, and a mottled soap of good quality 
 does not leave more than about one per cent. 
 
 “ If there should be a sensible amount of residue from white soap, or 
 more than one per cent, from mottled soap, some accidental or fraudulent 
 admixture may be -suspected — silica, alumina, gelatine, &c. — the quantity 
 and nature of which may be determined by analysis. 
 
 “ The quantity of alkali contained in the soap is easily determined by 
 means of the alkalimeter: a known quantity of the soap is dissolved in 
 water and tried by the test acid. 
 
 “ There is no difficulty in ascertaining in the same assay the quantity 
 of the fatty substance. For this purpose 150 grains of pure white wax, 
 free from water, are added to the liquid after saturation with the test acid, 
 and the whole heated to complete liquefaction ; it is then allowed to cool, 
 and when it has become solid, the cake of wax and fatty matter which 
 have united is removed and washed, dried and weighed ; the augmentation 
 in weight beyond the 150 grains employed will give the weight of the 
 fatty matter. 
 
 “ The liquid decanted from the solidified wax may afterwards be tested 
 to ascertain the purity of the base. 
 
 “The solution of the sulphate may also be evaporated, and by an 
 examination of its crystalline form, or by means of chloride of platinum, it 
 may be ascertained whether the base be soda or potash, or a mixture of 
 the two. 
 
 “ As to the nature of the fatty substance, it is ascertained, with more 
 or less certainty, by saturating the solution of the soap with tartaric acid, 
 collecting the fat acids, and taking their point of fusion. It is possible, at 
 least, by this to prove the identity or the absence of identity with the 
 
STRONTIUM. 
 
 115 
 
 sample in the soap supplied, for instance whether it is made from oil or 
 tallow, &c. The odour developed by the fatty acids at the moment of the 
 decomposition of the soap by acids assisted by heat, will often indicate 
 the nature of the fatty substance employed in its fabrication, or that at 
 least of which the odour may prevail.” 
 
 The impurities found in soaps are many, and often used to enable them 
 to retain water. They are gelatine, dextrine, potato starch, pumice stone, 
 silica, plaster of Paris, clay, salt, chalk, resin, and carbonate of soda. 
 
 Barium. (Ba 137*2.) 
 
 This is a metal having a silver-white lustre and considerable ductility ; 
 it is four times heavier than water, oxidises rapidly when exposed to the 
 air, forming barytes ; it is one of those substances termed earths, and has 
 strong alkaline properties. This earth, which was decomposed and its 
 metallic basis discovered by Sir H. Davy in 1808, exists abundantly in 
 Nature in combination with sulphuric acid, in the form of sulphate of 
 barytes ( heavy spar), and with carbonic acid forming carbonate of barytes, 
 both insoluble. The soluble salts are generally prepared from the sulphate, 
 which is ground fine, mixed with charcoal, and kept at a strong red heat 
 in a crucible for about an hour. Sulphide of barium is thus formed. This 
 is acted upon by nitric or hydrochloric acid, to form the nitrate or 
 chloride, according as one acid or the other is used. These salts may also 
 be obtained from the carbonate direct by merely digesting the mineral in 
 the acid. The sulphate is occasionally used for giving weight to goods 
 and diluting pigment colours in calico-printing. 
 
 Chloride of Barium is a crystalline salt ; 100 parts of cold water 
 dissolve about 43 parts of it. A solution of this salt forms the common 
 test for the presence of sulphuric acid in any substance. 
 
 Nitrate of Barytes is also a crystalline salt, but not so soluble in 
 water ; 100 parts of cold water dissolve only about 8£ parts of it. The affinity 
 of barytes for sulphuric acid is so great, it takes it from every soluble sub- 
 stance, and forms with it an insoluble precipitate. Hence it is that barytes 
 is pre-eminently the test for sulphuric acid. 
 
 The Acetate of Barytes is sometimes used to precipitate the sulphuric 
 acid of alum and form an acetate of alumina.; but this use of the salt is 
 not very extensive. 
 
 Strontium. (Sr 87 *5.) 
 
 This is a metal very similar to barium in appearance and properties. 
 Its oxide is termed Strontia. It is another of the earths which has alkaline 
 properties, and which occurs in Nature in combination with carbonic and 
 sulphuric acids, although not very abundantly. The soluble salts are pre- 
 pared from the carbonate, by acting upon it with nitric or hydrochloric 
 acids by which are formed nitrate of strontia, or chloride of strontium, both 
 
116 
 
 SULPHATE OF LIME. 
 
 crystallisable salts. Their solutions precipitate sulphuric acid, but not so 
 fully as the solutions of barytes. The salts of strontium are used for fire- 
 works, having the property of communicating a red colour to flame. 
 
 Calcium. (Ca 40.) 
 
 This is a metal the oxide of which is lime — one of the most widely 
 diffused of all the earths, and also one of the most generally useful. It 
 exists abundantly in Nature as carbonate and sulphate of lime. Ordinary 
 limestone, chalk, marble, &c., are carbonates; gypsum, plaster of Paris, 
 &c., are sulphates. 
 
 Caustic Lime, or calcium oxide, is obtained by heating the carbonate 
 to redness — as done in the ordinary process of lime-burning in a kiln. The 
 carbonic acid is driven off, and caustic or burned lime remains. Caustic 
 lime combines rapidly with one equivalent of water, becoming a hydrate, 
 and falls into a fine powder, commonly termed slaked lime. During this 
 operation, much heat is evolved from the water passing from a fluid to a 
 solid state in combining with the lime. 
 
 Lime is soluble in water, and the solution is termed lime water. It 
 has an alkaline reaction, and is much used in the dye-house. It takes 78 
 gallons of water at 60° to dissolve one pound of lime ; 97 gallons at 130° ; 
 and 127 gallons at 212°. So that cold water dissolves more lime than hot 
 water ; and the practice of putting boiling water upon lime, in order to get 
 a strong solution, is erroneous. When a boiler is filled with cold lime water 
 and brought to a boil, as when oranges are to be raised, we see why there 
 is always a quantity of powder deposited ; for, as the hot water does not 
 hold the same quantity of lime in solution as the cold, the surplus is 
 deposited in fine crystalline grains. Lime water exposed to the air absorbs 
 carbonic acid rapidly, forming thin pellicles on the surface, which, falling 
 down from time to time, the lime in the solution ultimately gets all 
 deposited. Lime in solution is extensively used in the dye-house, and 
 will be referred to when describing the operations in which it is used. 
 
 Lime combines with different acids, forming a series of salts, most of 
 which are of little practical use to the dyer. With hydrochloric acid it 
 forms the chloride of calcium — a very deliquescent salt, which is some- 
 times on that account used for absorbing moisture from gases, &c. It is 
 formed in the spontaneous decomposition of bleaching powder, which it 
 makes damp. ("See page 59.) 
 
 Sulphate of Lime. — Sulphuric acid and lime have a strong affinity 
 for each other, forming sulphate of lime or gypsum. It is nearly insoluble 
 in water, and is formed in the common blue vat by the lime decomposing 
 the sulphate of iron. It is held in solution in very minute quantities in 
 some spring waters. 
 
ALUM. 
 
 117 
 
 Carbonate of Lime ( Limestone ) is insoluble in water, but if the water 
 holds carbonic acid in solution there is formed a bicarbonate of lime, which 
 is slightly soluble in water. 
 
 The best test for the presence of lime is a solution of oxalate of 
 ammonia, which gives with lime a white precipitate. 
 
 Magnesium. (Mg 24.) 
 
 This is a silver-white metal, ductile and hard ; it oxidises rapidly when 
 exposed to moist air or water. It has of late become of great importance 
 in many operations of philosophical research from its property of burning 
 in the air. When made into wire or thin plates and heated at one end, it 
 burns and gives out an intense white light ; it continues to burn like an 
 organic substance, giving ample time for taking photographs by it, and 
 examining dark places, &c., leaving a white ash of pure magnesia. 
 
 Magnesia. — This oxide is the well-known alkaline earth magnesia, which 
 is found abundant in Nature in the state of carbonate. There are immense 
 beds of it in combination with lime, termed magnesian limestone. The 
 carbonate is soluble in water, which contains free carbonic acid, and 
 imparts to the water a slightly alkaline reaction. Magnesia combines with 
 the acids, and forms with them a series of salts of considerable importance 
 in several manufactures and in medicine, but they are not much used in 
 dyeing. The salt principally used is the sulphate (Epsom salt), which 
 is easily prepared by saturating magnesia or carbonate of magnesia with 
 sulphuric acid, and evaporating the solution to crystallise the salt. Salts 
 of magnesia are found in several springs ; such salts in water are very bad 
 for delicate colours. The best test for its presence is phosphate of soda, 
 with which, after long stirring, it gives a white precipitate, even with very 
 minute quantities. 
 
 Aluminum. (A1 27-3.) 
 
 The metal aluminum is obtained by decomposing a compound of 
 chloride of sodium and aluminum by heating it with sodium. It is a 
 white metal resembling zinc in colour and hardness, and is both malleable 
 and ductile. It preserves its brightness in the air, and is now much used 
 for trinkets and also for some philosophical purposes ; it is very light and 
 used for making fine weights for chemical purposes. It is easily dissolved 
 in hydrochloric acid ; it forms alloys with copper resembling gold, which 
 are used for cheap jewellery. 
 
 Alumina. — There is only one oxide of aluminum, A1 2 0 3 . This is 
 termed alumina, which is the pure plastic principle of clay, and is exceed- 
 ingly abundant in Nature. It combines with acids, forming salts. 
 
 Alum. — Alumina is easily dissolved in sulphuric acid, forming the 
 sulphate of alumina, which crystallises with much difficulty; but this 
 
118 
 
 ALUM. 
 
 salt has a strong affinity for some other sulphates, such as the sulphate 
 of potash, so that when these two salts are mixed, or when a salt of 
 potash is added to a strong solution of sulphate of alumina, they combine 
 and form common alum, which is easily crystallised. This is what 
 chemists denominate a double salt, being composed of two sulphates 
 — the sulphate of alumina and the sulphate of potash. This salt has 
 been known, and in general use among dyers, since the earliest accounts 
 we have of their processes ; but the true nature of its composition was 
 not known till the present century. The alchemists knew that sulphuric 
 acid was one of its constituents ; and during -the last century it was dis- 
 covered that the precipitate which falls when the acid is neutralised by an 
 alkali, was a particular kind of earth which chemists called alumina, be- 
 cause of its being obtained from alum. Amongst other peculiar properties 
 of alumina it has a strong attraction for organic matter, which it withdraws 
 from solutions with such force, that if the purest water be not used when 
 preparing it, the alumina is coloured; and when digested in solutions of 
 vegetable colouring matters, provided the alumina be in sufficient quantity, 
 i t will carry down all the colouring matter from the liquid. By this means 
 the pigments called lakes are formed, and it is this property that makes it 
 so valuable as a mordant. The fibre of cotton, when charged with this 
 earth, attracts and retains colouring matters. 
 
 A very pure alum is obtained in the Roman States from alum stone , 
 a mineral which is continually produced at the Solfatara, near Naples, 
 and other volcanic districts, by the joint action of sulphurous acid and 
 oxygen upon some of the felspathic rocks. This mineral contains an 
 insoluble subsulphate of alumina with sulphate of potash ; but it is 
 partially decomposed by heat ; so that, for the preparation of alum, the 
 mineral is simply heated, till sulphurous acid begins to escape, and is then 
 treated with water, by which process a very pure and excellent alum is 
 procured — much superior to that manufactured in this country. A large 
 proportion of the alum of this country is manufactured from a mineral 
 termed alum shale , a kind of clay slate much impregnated with sulphide 
 of iron, which is essential to this mode of manufacture. The general 
 composition of this alum ore, as it is< also called, is as follows, observing 
 that the proportions of the several components vary according to the depth 
 from which the ore is obtained: the table is therefore to be considered as 
 giving only the average constitution : — 
 
 Sulphide of iron, 
 
 26-5 
 
 Oxide of iron, 
 
 3-1 
 
 Alumina, . 
 
 18-3 
 
 Silica, 
 
 10-5 
 
 Lime and magnesia, 
 
 3-0 
 
 Magnesia, potash, soda, 
 
 1-4 
 
 Coaly matter, 
 
 287 
 
 Water, . . . . 
 
 8-5 
 
 100-0 
 
ALUM. 
 
 113 
 
 The ore is built up in large heaps with alternate layers of coal : these 
 heaps are set on fire, and allowed to burn for several weeks. During this 
 roasting process, a portion of the sulphur is expelled as sulphurous gas ; 
 but the greater portion of it is converted into sulphuric acid, by taking 
 a proportion of oxygen from the peroxide of iron formed in the burning. 
 The sulphuric acid does not, however, remain isolated, but combines with 
 the iron and alumina, and forms sulphates. The roasting being com- 
 pleted, the material of the heap is removed to large tanks or pits, into 
 which water is allowed to flow, which dissolves out the sulphates formed 
 in the roasting process. The solution is run into large tanks or pans and 
 evaporated, either by causing a current of dry heated air to pass over 
 the surface of the liquid or by fire. When the solution is sufficiently 
 concentrated, the sulphate of iron crystallises, and is then removed; 
 the sulphate of alumina being very difficult to crystallise, remains 
 in solution. All the iron having by this means been separated, the 
 sulphate of alumina in solution is removed to other vessels, where there 
 is added to it sulphate of potash, chloride of potassium, or other salts of 
 potash. There is then formed the double salt of potash and alumina 
 (alum), which, afte» a few days standing, crystallises, and is removed 
 and packed for the market. There are some modifications of this process 
 adopted by different makers, but this description exhibits the general 
 practice of the manufacture, and illustrates sufficiently the principle upon 
 which the practice is necessarily based. Large quantities of alum are also 
 manufactured by digesting pure clay, previously calcined in strong vitriol, 
 by which means sulphate of alumina is formed, which is afterwards treated 
 with salts of potash, as described above. 
 
 Soda or its salts may be used in the operation instead of potash, these 
 would give a soda alum; but, notwithstanding its being cheaper, there are 
 practical objections to it. Soda alum is not so easily crystallised as 
 common alum, and it effloresces when exposed to the air, which makes it 
 take the appearance of a dry powder. Sulphate of ammonia may also be 
 used instead of potash, giving an ammonia alum, which, however, is 
 expensive, and. possesses no corresponding advantage over the ordinary 
 article. 
 
 The following analysis by Dr. Thomson,, of the alum made in in this 
 country, will be useful : — 
 
 Potash, ...9-86 
 
 Alumina, 11-09 
 
 Sulphuric acid, 32-85 
 Water, ..46-20 
 
 Symbols. 
 
 EA1 2 S0 4 + 12H 2 0. 
 
 100-00 
 
 Thus every 100 lbs. of alum contain 46 lbs. of water. From the nature of 
 the processes by which the alum is manufactured, we may expect it to 
 contain small traces of sulphate of iron, a substance very deleterious to its 
 
120 
 
 ALUM. 
 
 use as a mordant or alterant. Iron may be detected by dissolving a little 
 of the alum in distilled water, and adding a few drops of a solution of red 
 prussiate of potash ; or boiling a little with the addition of a few drops 
 of nitric acid, and adding yellow prussiate of potash. In both cases a 
 deep blue colour is immediately produced if iron is present. The 
 addition to a solution of alum of a few drops of gallic acid will give 
 a black colour if iron be present. Or, if a little alum be put into 
 a vessel, and caustic potash added till the solution is strongly alkaline, 
 then the whole boiled and set aside to cool and settle, the alumina 
 will be dissolved, and if iron be present, it will subside to the bottom 
 as a brownish precipitate. When the proportion of iron is con- 
 siderable, it is better to reject the alum altogether, especially for bright 
 light shades. We have often experienced bad effects from the use of such 
 alum upon light shades when dyeing to a particular pattern. Having 
 obtained the particular depth of shade, and adding a little alum as raising, 
 the iron, by combining with the sumach upon the uloth, produced a colour 
 two or three shades darker than required, leaving no alternative but to 
 take off the colour and dye anew — a process much more difficult, and which 
 produces a colour much less brilliant than is the first. 
 
 Pure alum is soluble in water, and should give a colourless solution. 
 
 One gallon of 
 
 water at 54° 
 
 Fah. dissolves 1 lb. alum. 
 
 One „ 
 
 86° 
 
 75 
 
 2 
 
 One ,, 
 
 140 Q 
 
 55 
 
 3 
 
 One „ 
 
 158° 
 
 55 
 
 9 
 
 One 
 
 212° 
 
 J5 
 
 35 ,, 
 
 Alum forms but a weak mordant for cotton goods, owing, probably, 
 to the strong attraction which the sulphuric acid has for the alumina ; 
 there are three proportions of acid to every two of alumina. But if we 
 neutralise a portion of the acid, so that no more remains than is necessary 
 to hold the alumina in solution, which, according to experiment, is not 
 above a third of the acid contained in common alum, its properties as a 
 mordant are greatly improved. This may be done by taking a quantity of 
 carbonate of soda in solution, and adding this gradually to the alum 
 solution, stirring all the time: the alumina is at first precipitated; but by 
 keeping up the agitation, the precipitate again dissolves : continue till all 
 the precipitate is redissolved. In this state alum is a more powerful 
 mordant for cotton, as the base is held more feebly by the sulphuric acid, 
 and is readily detached by the superior affinity of the cloth to form a 
 mordant ; and thus prepared, it is perfectly pure — any iron formerly 
 present is precipitated in the process. Alum in this state is known by the 
 name of cubical or basic alum, from the form in which it crystallises. We 
 have already referred to Roman alum being superior to other alums. 
 
 This cubical alum, as it is termed, is also prepared on the large scale, 
 by boiling twelve parts of alum with one part of pure slaked lime. On 
 
ACETATE OF ALUMINA. 
 
 121 
 
 cooling, the alum crystallises, or the solution may be used without crystal- 
 lising and redissolving. The composition of alum prepared in this way is — 
 
 Sulphuric acid, ...33-95 
 
 Alumina, 11-40 
 
 Potash, 9-04 
 
 Water, 45-61 
 
 100-00 
 
 Sulphate of Alumina. — We have already stated above that alum is 
 occasionally made by digesting clay in vitriol. There is a large quantity of 
 sulphate of alumina made in this way ; and instead of converting it into 
 alum, the solution is evaporated to dryness, and the salts caked and sold 
 as cake alum, or patent alum. This salt is seldom pure, and very irre- 
 gular in composition. It is not well suited for light dyes, but may be used 
 for some dark shade and for the preparation of other aluminous salts ; it 
 contains more alumina than alum. 
 
 Acetate of Alumina. — The most common, and we believe the best 
 method of using alumina as a mordant for cotton, is by substituting acetic 
 acid for sulphuric acid in combination with it. The acetate of alumina has 
 several advantages over the sulphate: 1st, the acetic acid is not so hurtful 
 in its action upon the vegetable colouring matters; 2nd, it holds the 
 alumina with much less force than sulphuric acid, and consequently yields 
 it much more freely to the cloth ; and 3rd, being volatile, a great portion 
 of the acid flies off during the process of drying. When strong colours 
 are wanted, and the mordant is of such a nature as will admit of being 
 dried, it is better to dry the cloth from the mordant previous to dyeing 
 This last property of acetic acid is, therefore, very convenient, as it frees 
 the cloth from any superfluous acid which may have been in the mordant ; 
 besides, it has been found that during the drying by heat, the soluble acetate 
 is converted into a less soluble subacetate. We may here put the dyer in 
 mind that when goods containing volatile acids are drying, no other kind 
 of goods should be allowed to be in the same apartment, as the acid will be 
 absorbed by them, and will affect almost any colour that either has been 
 or may be put upon them. Many unpleasant and also expensive conse- 
 quences occur from the neglect of these precautions. 
 
 The acetate of alumina is easily prepared by mixing a solution of 
 acetate of barytes, lime, or lead with alum. When any of these salts are 
 added to alum, a double decomposition takes place ; the sulphuric acid of 
 the alum combines with the base of the salt, which falls to the bottom, and 
 the acetic acid unites with the alumina, forming acetate of alumina, which 
 remains in solution mixed with the sulphate of potash, which formed a 
 constituent of the alum. The acetate of lead is the salt generally used for 
 this purpose in the dye-house; the proportions of the lead and alum 
 are seldom taken in their equivalents, but vary according to the nature of 
 
122 
 
 ACETATE OF ALUMINA. 
 
 the colour to be dyed, or rather, the peculiar taste of the dyer, for the- 
 preparation of this substance is one of those operations which every one 
 who practises it thinks he has the best method ; but so far as we have had 
 an opportunity of knowing, the superiority only existed in the mind of the 
 individual, or rather in its being his secret. In the proportions generally 
 used for the preparation of this mordant there is never a sufficient quantity 
 of acetate of lead to precipitate all the sulphuric acid in the alum. The 
 alum having 4 equivalents of sulphuric acid, would, require 4 equivalents of 
 acetic acid to take its place. Thus — 
 
 Alum 
 
 contains, 
 
 exclusive of water, 
 
 It would take 
 4 proportions 
 acetate lead. 
 
 { 2 Al... 
 
 3 S0 4 „ v 
 
 1 K.. A—, 
 
 ISO, vX/ 
 
 3 Acetic acid/A<\ 
 
 1 Acetic acid,/ \\ 
 
 4 Pb ... A 
 
 Acetate of alumina. 
 
 Acetate of potash. 
 
 Sulphate lead. 
 
 So that the proper equivalent of acetate of lead is as- near as possible 6f lbs. 
 to 4f lbs. of alum. This is far from the proportions used, shewing that the 
 mordant is not a pure acetate of alumina, but a mixture of salts-, probably 
 of cubic alum, with acetate of alumina and sulphate of potash. 
 
 The following method and proportions for dyeing light shades on fine 
 muslin cloths we have generally found to answer very well: — Into a boiler 
 or pot put 20 lbs. of crystallised alum with about 9 gallons water, and 
 boil till the alum is completely dissolved. In a separate vessel dissolve 20 
 lbs. of acetate of lead in about 3 gallons of boiling water. This is added 
 to the alum while at a boiling heat, and well stirred. The sulphuric acid 
 combines with the lead, forming an insoluble sulphate of lead, which falls 
 to the bottom as a heavy white precipitate ; the soluble part constitutes 
 the mordant. The differences in the preparation of this mordant lie in the 
 proportion of lead varying from one-half to equal weights with that of the 
 alum. There is also added to the alum and lead a quantity of carbonate of 
 soda, varying from 4 to 8 ounces to the 5 pounds of alum. This is added 
 for the purpose of neutralising a portion of the acid ; but there are many 
 dyers who will not use soda or any other alkaline substance when light 
 bright shades aro wanted, under the impression that the colour is much 
 brighter without alkalies. Some use lime ; soda, however, is best. Without 
 soda or some other alkaline substance, the mordant is not so effective. 
 There are also some who object to the use of soda, as it throws down 
 the alumina ; but we have already noticed that a very little acid holds 
 the alumina in solution ; so that although soda, when added to the acetate 
 of alumina, appears to precipitate the alumina, by a little agitation the 
 precipitate is again dissolved, forming a mordant better adapted for a 
 strong colour. From the following recipes, taken from a French work on 
 dyeing, it will be observed that the quantities of the aluminous mordants 
 are similar both in England and France: — 
 
ACETATE OF ALUMINA. 
 
 123 
 
 60 gallons boiling water, 
 
 100 pounds alum, 
 
 100 pounds acetate of lead, 
 
 10 pounds crystallised sod 
 
 80 gallons boiling water, 
 
 100 pounds alum, 
 
 50 pounds acetate of lead, 
 
 6 pounds soda, 
 
 In addition to the above, I 
 Manufactures , article “ Calico-Printing,” gives another proportion — 
 
 50 gallons boiling water. 
 
 100 pounds alum. 
 
 75 pounds acetate of lead. 
 
 10 pounds soda. 
 
 The following curious phenomenon was observed by Gay Lussac — viz., 
 that the solution of a pure salt of the acetate of alumina may be boiled 
 without decomposition ; but if sulphate of potash, or any other neutral salt 
 of an alkali, be present, the solution becomes turbid when heated, and a 
 basic salt precipitates, which dissolves again on cooling. Now the acetate 
 of alumina prepared from the common alum always contains sulphate of 
 potash. If by the presence of this salt a portion of the acetate of alumina 
 is thrown down when hot, and incorporated with the sulphate of lead, 
 which falls in a very dense state, it may there be lost to the dyer. After 
 decanting the clear acetate, put a quantity of cold water on the precipitate 
 and stir well, and when it settles remove the clear and mix with the first. 
 
 Nearly all the acetate of alumina used in dyeing is prepared from pyro- 
 ligneous acid, as a separate manufacture, and sold to the dyer in a liquid 
 state ready for use ; it is called by calico-printers red liquor , but by dyers 
 mordant. No other substance is distinguished as mordant. All other 
 mordants have their technical names. The pyroligneous acid is one of the 
 products of the destructive distillation of wood. The hardwoods, such as 
 oak, ash, birch, and beech alone are used : they are put into large cast- 
 iron cylinders, so constructed that a fire plays about them so as to keep 
 them at a red heat, and having openings through which all volatile matter 
 escapes by pipes, which lead into condensing vats. The products thus 
 obtained consist principally of pyroligneous acid, mixed with a black tarry 
 matter, having a very strong smell, from which the acid had its name, 
 although it has been long since known that it is simply acetic acid (vinegar). 
 There is a great variety of other substances present, some of which have 
 very singular properties, such as pyroxilic spirit, or mithylene. The pro- 
 ducts of the distillation of the wood are allowed to stand for some time, 
 after which as much of the tarry matter as swims is skimmed off ; the 
 remainder is filtered and is put into a boiler and heated a little, and lime 
 
 This mordant is best adapted 
 for reds. 
 
 
 This is the best for bright 
 yellows. 
 
 )r. Ure, in his Dictionary of the Arts and 
 
124 
 
 ACETATE OF ALUMINA. 
 
 added by degrees, till the acid is neutralised; then a quantity of lime is 
 added in excess, and the whole is made to boil ; this throws up the tarry 
 matter to the top, where it is taken off. When it is purified as much as it 
 can be by this means, it is syphoned off into another boiler, and a quantity 
 of alum is added ; the acetate of lime, the sulphate of alumina and potash 
 mutually decompose each other ; the sulphate of lime falls to the bottom, 
 and the acetate of alumina remains in solution, which is the red liquor or 
 mordant of the dyers. When sent to the dyers it has a specific gravity of 
 1,090 (18 Twaddell), although it is often weaker. It has a dark-brown 
 colour, and a very strong pyromatic odour. When the acetic acid is wanted 
 pure, it passes through a number of other processes, which do not come 
 within our province to describe in this place. 
 
 There are considerable differences in the quality of red liquor, which 
 the mere specific gravity does not indicate; the specific gravity can be brought 
 up by the addition of foreign matters, such as British gum, dextrine, and such 
 like. A very simple method may be adopted to test the effective quality of 
 the mordant: — Take a little of the liquor and evaporate to dryness, then 
 burn the residue at a red heat until white in colour ; put this into distilled 
 water, which will dissolve out all but the alumina. Another way is by 
 digesting a little of the red liquor in nitric acid, adding ammonia until the 
 liquor smells of it, and then by filtering, the alumina is obtained upon the 
 filter-paper, which is dried and weighed. We will give four varieties here, 
 to shew the variableness in quality of the liquor as supplied to the dyer. 
 The quantity given refers to the percentage in solution : — 
 
 English red liquor- 
 
 —14° Twadd... 
 
 jacetate of alumina... 
 ^sulphate of potash... 
 
 ...15-3 
 ... -8 
 
 
 
 
 16-1 
 
 Scotch, No. 1 — 
 
 13^° Twadd... 
 
 (acetate of alumina... 
 ^sulphate of potash.. 
 
 ...11*5 
 .... 2-3 
 
 
 
 
 13-8 
 
 Scotch, No. 2 — 
 
 14° Twadd... 
 
 ("acetate of alumina... 
 (sulphate of potash... 
 
 M 
 
 I- 1 
 
 fci> 
 
 
 
 
 15-2 
 
 Scotch, No. 3 — 
 
 15° Twadd... 
 
 ^acetate of alumina... 
 ■(sulphate of potash... 
 
 ...12-2 
 ... 2-6 
 
 
 
 
 14-8 
 
 We have given these varieties to shew how little reliance ought to be 
 placed on the indications of the hydrometer. No. 3 is of a higher specific 
 gravity than the English red liquor, but far inferior as a mordant. Again, 
 such a mordant as No. 1 has a tendency to make light spots upon goods 
 dyed green by fustic or bark, the alumina being the effective agent in the 
 red liquor. The above is an ample illustration of the necessity of some 
 better mode of testing than by the hydrometer. 
 
ACETATE OF ALUMINA. 
 
 125 
 
 During the various applications of these aluminous mordants and the 
 manipulations attending them, many curious and interesting chemical 
 phenomena are witnessed by the dyer, although his familiarity with them 
 often prevents any particular remark; we shall instance one or two of those 
 ittendant upon the process of dyeing madder reds by means of acetate 
 of alumina. The cloth to be dyed is first thoroughly bleached and 
 dried, it is then padded or soaked in acetate of alumina, about the 
 specific gravity of 1,040 (8 Twaddell), and passed at full breadth through 
 nipping rollers (squeezers). These are large rollers covered with cloth, 
 which revolve one upon another. The pressure upon the piece, as it passes 
 through for the purpose we are describing, ought to be such that it will dry 
 in five minutes, on passing over rollers in a stove heated to 160° Fah. Pieces 
 mordanted with acetate of alumina and dried at a great heat, are highly 
 charged with electricity. If the hand be suddenly drawn along the piece, 
 a complete shower of fire is observed, with a sharp cracking noise, at the 
 'same time a prickling sensation is felt. Whether this has any effect upon 
 the mordant, in its immediately combining with other substances, we do 
 jnot know ; but cloth in this state is very difficult to moisten : water runs 
 off it as off a duck’s wing; but we offer no explanation. After being dried, 
 the goods are passed through a dung bath, made up with about one part 
 mow’s dung to fifty parts water, at a heat of 130° Fahrenheit; from this 
 they are well washed through the dash wheel. Into a boiler of cold water 
 is put from one to three pounds of madder, according to the colour wanted, 
 
 ;j for every pound of cloth. The cloth is put in, and a fire is kindled under 
 |the boiler, and so regulated that it will boil in two hours, during which time 
 | the cloth is kept running over a winch or wheel, first in one direction and then 
 in the other, and kept spread as much as possible, so that the whole surface 
 :|may be equally exposed to the dyeing operation. The infusion is kept at 
 | the boiling point from twenty to thirty minutes: this, with washing first 
 | through bran and then water, completes the dyeing operation. If a white 
 !j pattern be wanted upon these reds, the pattern is printed upon the goods 
 !} with citric acid (about 25° of Twaddell, thickened with pipe-clay and gum), 
 about twelve or twenty-four hours after being dried from the mordant. 
 This decomposes the aluminous mordant upon these parts, so that no dye 
 adheres to them afterwards. It is of the utmost consequence that the 
 !i goods be thoroughly cooled previous to printing on the resist, otherwise 
 there is danger of it not being successful. 
 
 Owing to differences in the manipulation, or a little variation upon some 
 of these processes, several curious changes take place upon the mordant, 
 jj For example, were the pieces merely washed with water from the mordant, 
 previous to printing on the resist acid, although the treatment were 
 every way else the same, the discharge of the mordant is not effected; 
 those parts upon which the citric acid is printed will be scarcely observ- 
 able after the cloth is dyed, while in the other case they are perfectly 
 j white. 
 
 A somewhat similar result, in reference to the action of the discharge 
 
126 
 
 ACETATE OF ALUMINA. 
 
 acid, takes place if the heat of the stove in which the goods are dried from 
 the mordant exceeds a certain temperature, or if dried upon steam rollers. 
 No acid printed upon the cloth after this will produce a white, except it 
 be of a strength that will destroy the fabric of the goods; besides this, the 
 colours afterwards dyed upon mordants heated in this manner are extremely 
 bad, being heavy and dull. 
 
 Various opinions have been offered by practical men upon the pro- 
 bable cause of these changes : some suppose that by the excess of heat the 
 acetate of alumnia is altogether decomposed, the acetic acid flying off, and 
 the alumina left in the goods adhering with such an affinity, that it requires 
 a stronger acid than the cloth will bear to disengage it ; but from the 
 similarity of the effects which take place by merely washing the piece from 
 the mordant, this opinion is liable to objection, for the subacetate of 
 alumina is not decomposed by washing with water; however, different 
 causes may produce the same effects. If this opinion be correct, the cir- 
 cumstance of a bad colour resulting from the acetate being decomposed, 
 will be a proof that it is not the alumina alone which constitutes a mordant, 
 but its salt ; in this case, it is the subacetate of alumina — the acetic acid 
 being an essential ingredient to the dyeing process. This we are inclined 
 to believe, for in those mordants, as we have already stated, where the acid 
 can be separated by washing, the proper colour is not produced until some 
 salt or acid be added to the colouring matter as an alterant. It is supposed 
 by some writers that the dunging and washing extract the acid from the 
 mordant, and leave the base upon the cloth. This we conceive to be an 
 error ; for although the part which dung acts in these processes is not well 
 understood, yet, from the analysis of this substance, and the nature of the 
 salts which are supposed to be useful in these operations, there is no pro- 
 bability of the aluminous salt being decomposed. Oge principal use of the 
 dung bath is to combine with and carry off anyloose or supernatant mor- 
 dant which may be upon the cloth, not combined, and which might affect 
 the colour, or more particularly the parts wanted to be white. 
 
 Alumina combines with all the acids, forming salts similar to those 
 already described, and all difficult to crystallise, except as double salts — 
 such as alum — which they form with other salts besides those named ; but 
 none of the others have been introduced into the dye-house. 
 
 Alumina, as an earth, is of great value in many other arts, as in pottery, 
 brickmaking, &c. It also forms the bases of some of the finest precious 
 stones : the sapphire and ruby, for example, are nearly pure alumina. 
 
 The salts of alumina, such as alum, act towards other salts and re- 
 .agents, as under : — 
 
 Potash White precipitate, which is redis- 
 
 solved in an excess of the precipi- 
 tant. 
 
 Ammonia White precipitate, insoluble in an 
 
 excess of the precipitant. 
 
MANGANESE. 
 
 127 
 
 Carbonate of potash White precipitate, not soluble in an 
 
 excess of the precipitant, but 
 soluble in caustic potash. 
 
 Caustic soda and its carbonate act in the same way as caustic potash 
 and its carbonate. 
 
 Carbonate of ammonia and phosphate of soda act in the same way as 
 carbonate of potash. 
 
 All these precipitates are soluble in acids. 
 
 Oxalic acid No precipitate. 
 
 Yellow prussiate of potash Precipitate, after standing for 
 
 some time. 
 
 Red prussiate of potash No precipitate. 
 
 All these precipitates of alumina have a bulky and a kind of plastic 
 | appearance, easily recognised and distinguished. 
 
 When a substance containing alumina is heated to redness, especially 
 j before the blowpipe, and is touched with a solution of nitrate of cobalt, 
 and then again heated, it takes a beautiful blue colour. In this way a very 
 small portion of alumina may be detected in any solid substance ; but when 
 the substance is in solution, it must be detected by the reaction of some of 
 the re-agents given above. It may also be noticed, that when operating to 
 obtain a precipitate, it is necessary to be careful that only pure water is 
 used for washing the precipitate. If the water is not pure, the precipitate 
 will attract the impurity, especially if it consists of any organic matters, 
 and thus become tinged, and assume an appearance as if iron were present. 
 
 The next general division of chemical elements consists of the Metals 
 Proper. These are very numerous ; but a great many of them are so rare 
 that they have been seen by a very few chemists, and are only obtained in 
 particular localities, consequently their properties have not been much inves- 
 tigated, and no practical applications have been made of them. Of these a 
 very short description will suffice, so that our remarks may be more 
 extended upon those which have a known practical value. 
 
 Manganese (Mn 54). 
 
 This metal is not found in Nature in a metallic state, but exists 
 abundantly in combination with oxygen. From this circumstance it was 
 long considered a species of earth, like magnesia, and was consequently 
 called magnesia nigra; but it was discovered to be the oxide of a metal in 
 1774 by Scheele and Gahn, and was then named manganese. 
 
 As a metal, it has a greyish-white lustre, resembling cast iron ; it is 
 very difficult to fuse, and it combines with oxygen so quickly that it cannot 
 be kept in the open air. It passes into several states of oxidation. The 
 
128 
 
 MANGANESE. 
 
 one in which it generally exists in nature is the peroxide or dioxide, having 
 2 proportions of oxygen to 1 of metal = Mn0 2 . When this oxide is 
 heated at a low red heat, it loses a part of its oxygen, and passes into the 
 state of sesquioxide — Mn 2 Os. When heated to bright redness, it loses 
 more oxygen, and becomes what is termed red oxide, or a mixture of the 
 protoxide MnO and of the sesquioxide Mn 2 0 3 . The peroxide does not 
 unite with either acids or alkalies. When boiled with sulphuric acid, one 
 proportion of the oxygen is evolved, and the protoxide MnO unites with 
 the acid, and forms sulphate of manganese, which is used in dyeing. 
 
 Peroxide, or black 
 oxide of manganese 
 
 Sulphuric acid 
 
 0 ... 
 
 Oxve-en fras. 
 
 0 ... 
 
 
 Mn. \ 
 
 
 Hi..\ 
 
 Water. 
 
 S0 4 
 
 Sulphate of manganese. 
 
 When the peroxide is digested in hydrochloric acid, chlorine is evolved, 
 and chloride of manganese formed. This is often done in houses for the 
 purpose of fumigation. The reaction is thus expressed: — 
 
 Four proportions hydro 
 chloric acid 
 
 Binoxide manganese, 
 
 _Chlorine gas. 
 
 Water. 
 
 Water. 
 
 Chloride manganese. 
 
 The oxide of manganese is extensively used in the manufacture of 
 bleaching powder, for obtaining the chlorine from common salt. (See 
 page 49.) 
 
 Manganese combines with almost all the acids forming salts, which 
 in their crystallised or dry state have less or more of a pinky hue. In 
 making these salts from the peroxide, there is always oxygen liberated; 
 they are therefore all what are termed salts of the protoxide. But by 
 removing the acid the protoxide soon combines with more oxygen, and 
 becomes brown. It is this circumstance that has made it applicable in 
 dyeing. In preparing any of the salts of manganese for dyeing purposes, 
 care should be taken that the salt is free of iron, as that metal is deleteri- 
 ous. The sulphate of manganese may be freed from iron by exposing it to 
 a red heat, then dissolving the residue in water. By this means the iron 
 present is peroxidised, it is thus rendered insoluble, and consequently sinks 
 to the bottom. 
 
 When cotton is passed through a solution of sulphate of manganese, 
 and then through a weak solution of an alkali, the manganese oxide is left 
 within the fibre, and by exposure becomes brown by attracting more oxy- 
 gen. Or if the cloth be immediately passed through a solution of weak 
 
IRON. 
 
 129 
 
 bleaching liquor, the protoxide is converted into a higher oxide without 
 exposure. This is the method generally adopted; it gives a brown, which 
 is dull and heavy, wants lustre, but is very permanent. 
 
 Mineral Cameleon. — When peroxide of manganese is fused with 
 carbonate or caustic potash, there is formed what has been long known as 
 the mineral cameleon. When this is put into water it produces first a deep 
 green solution, which passes rapidly to a red by absorbing oxygen. It 
 illustrates very forcibly the effects of oxygen in changing the colour of 
 substances, and the rapidity with which these changes take place; thus 
 teaching the necessity of attending to every condition, no matter how 
 apparently trifling, as often the merest trifle may be of the greatest con- 
 I sequence in a process. 
 
 Manganate of soda is now prepared on the large scale by heating a 
 Bmixture of caustic soda and finely-powdered manganese oxide to dull red- 
 ness for several hours. Solutions of this compound forms Condy’s disin- 
 Ifectant liquid, which is now very extensively used in disinfecting houses and 
 clothes. A little of this liquid put into a tub of water, and infected clothes 
 jput into it for a short time, removes infection, and will not stain the cloth. 
 Caustic potash may be used instead of soda in preparing this salt. 
 
 The salts of manganese, in solution, are affected by the following 
 re -agents : — 
 
 Potash, 
 
 Soda and ammonia, 
 
 1 Carbonates of potash and soda, 
 
 Yellow prussiate of potash, . 
 
 Red prussiate of potash, 
 
 Manganese is easily detected by this general property of turning brown 
 | when exposed to the air, and giving a brown with all the alkaline re -agents. 
 
 . Brown precipitate. 
 
 . Brown precipitate. 
 
 . Brown precipitate. 
 
 . Dirty-green precipitate. 
 . Brown precipitate. 
 
 Iron (Fe 56). 
 
 This is one of the most useful, generally diffused, and abundant of 
 the metals. There is almost no substance, whether organic or inorganic, 
 
 I quite free from iron. Its uses in the various arts and purposes of life are 
 linnumerable. The most common iron ores of this country are the black 
 land clay-band iron-stones, of which there are several varieties, and in 
 which the iron exists as a carbonate along with silica, alumina, carbon, 
 and a little sulphur. The ore is first calcined at a red heat, which expels 
 the carbonic acid and sulphur ; it is then mixed up with limestone and 
 coal, and put into a blast-furnace, and subjected to intense heat, the 
 effect of which is, that the silica and alumina combine with the lime and 
 form glass ; the coal takes the oxygen from the iron, and passes off with 
 it as carbonic acid; the metal meantime fuses, and, in consequence of 
 
 i 
 
130 
 
 SULPHATE OF IRON. 
 
 its superior gravity, sinks to the bottom of the furnace, while the glass and 
 scoriae float above it, and are run off separately when the furnace is tapped. 
 
 Iron combines with oxygen in two proportions — 
 
 Protoxide of iron, .... FeO. 
 
 Peroxide of iron, .... Fe 2 0 3 . 
 
 Both of these oxides unite with acids, and form with them two classes 
 of salts, distinguished from each other by affixing pro and per to their 
 names. Both salts are extensively used in the dye-house. 
 
 There is also what is termed the black or magnetic oxide of iron, 
 which is found as a distinct mineral in Nature ; and, also when peroxide of 
 iron is subjected to a high heat, it loses a part of its oxygen and forms the 
 magnetic oxide, which is considered a compound of protoxide and per- 
 oxide FeO -f- Fe 2 0 3 . 
 
 M. Fremy found what may be called a fourth oxide of iron, which he 
 obtained in combination with potash. This oxide can be obtained by heating 
 a mixture of nitrate of potash and peroxide of iron ; a brown mass is the 
 result, which, by digestion in water, gives a beautiful violet-red coloured 
 solution. The compound is very soluble in water. A large quantity of 
 water, however, decomposes it in course of time ; it becomes insoluble in 
 alkaline water, forming a brown precipitate, which readily dissolves in 
 pure water, and affords a fine purple-coloured solution. A temperature 
 of 212° dissolves it immediately; all organic substances decompose it; 
 and hence it is impossible to filter the solution. When the red solution is 
 treated with an acid, as soon as the potash is saturated oxygen is disengaged, 
 and peroxide of iron precipitated. If the acid be in excess, it dissolves the 
 peroxide, and gives rise to the formation of a persalt of iron. It was 
 stated by the discoverer to possess a powerful dyeing principle ; but we are 
 not aware of its having been put to that purpose. 
 
 Protoxide of iron is very difficult to be obtained in an isolated state, 
 on account of its great affinity for oxygen, which causes it to pass into the 
 state of peroxide very rapidly. When an alkali is added to a protosalt of 
 iron, the protoxide is precipitated as a hydrate of a greenish-grey colour, 
 which, by exposure to the air, soon becomes peroxide of an ochry-red 
 colour, as is seen almost daily in the dye-house during the dyeing of 
 nankeen or buffs by a protosalt of iron or copperas. 
 
 The goods are dipped into the sulphate of iron solution, and then 
 passed through lime water; the lime combines with the acid, and leaves 
 the hydrated protoxide precipitated within or upon the fibre ; the shade is 
 then greenish, but a slight exposure peroxidises the iron, and produces the 
 nankeen or buff. This property of the protoxide of iron of passing into the 
 peroxide, by its strong attraction for more oxygen, is beautifully applied in 
 some of the operations in dyeing besides the one referred to ; these will 
 be more fully described when treating of the blue vat. 
 
 Sulphate of Iron, or Ferrous Sulphate {green vitriol or copperas).— 
 This salt is very easily prepared, merely by adding metallic iron to sul- 
 
SULPHATE OF IRON. 
 
 131 
 
 huric acid, which has been diluted with three or four parts of water. The 
 ron quickly dissolves, with a copious evolution of hydrogen gas. The re- 
 ction taking place may be thus represented — 
 
 Sulphuric acid, 
 Iron, 
 
 ch 2 .. 
 
 lso 4 
 
 ..Fe..., 
 
 .Hydrogen gas. 
 
 Sulphate of iron. 
 
 When as much iron is dissolved as the acid will take, the solution is 
 vaporated by heat, until a pellicle or thin skin appears on the surface. 
 It is then set aside in a cool place, and in a short time there is formed 
 i quantity of green-coloured crystals of sulphate of iron. These crystals con- 
 tain seven proportions or equivalents of water of crystallisation, or in 100 
 parts 
 
 Sulphate of iron, FeS0 4 , 54-5 
 
 Water, 45.5 
 
 HXM) 
 
 If these crystals are heated a little above the boiling point of water, 
 Isay 238° Fah., they part with all this water, except one equivalent, or 
 kbout 10 per cent., and also lose their green colour, and become white. 
 '{The crystals of sulphate of iron require the following quantities of water 
 to dissolve them: — 
 
 1 gallon water at 50° Fah. dissolves 6 lbs. crystals. 
 
 1 
 
 11 
 
 59° 
 
 n 
 
 7 
 
 11 
 
 1 
 
 11 
 
 75° 
 
 11 
 
 11* 
 
 11 
 
 1 
 
 11 
 
 109° 
 
 M 
 
 15 
 
 11 
 
 1 
 
 11 
 
 115° 
 
 
 22f 
 
 11 
 
 1 
 
 11 
 
 140° 
 
 11 
 
 26* 
 
 11 
 
 1 
 
 1 1 
 
 183° 
 
 11 
 
 27 
 
 71 
 
 1 
 
 11 
 
 194° 
 
 11 
 
 37 
 
 11 
 
 1 
 
 11 
 
 212° 
 
 11 
 
 CO 
 
 CO 
 
 11 
 
 This table, which is of a similar character to tables of solubility of many 
 | ather substances dissolving in different quantities at certain temperatures, 
 I s interesting, and accounts for many of the circumstances occasionally 
 I observed in the dye-house, and puzzles the dyer — that sometimes the same 
 salt seems much more difficult to dissolve at one time than at other times. 
 
 1 [t also shews why crystallisation may occur much more rapidly at onetime 
 Iban at another. If we note the increase of heat and solubility of sulphate 
 of iron at different temperatures, we will see how irregular it is — 
 
 An increase of 9° 
 
 dissolves 1 lb., per gallon more than at 50° 
 
 5? 
 
 16° 
 
 11 
 
 
 ■11 
 
 11 
 
 59° 
 
 11 
 
 34° 
 
 » 
 
 H 
 
 11 
 
 11 
 
 75° 
 
 11 
 
 6° 
 
 11 
 
 7f 
 
 11 
 
 11 
 
 109° 
 
 11 
 
 25° 
 
 11 
 
 H 
 
 11 
 
 11 
 
 115° 
 
 11 
 
 43° 
 
 11 
 
 Of 
 
 11 
 
 11 
 
 140° 
 
 :i 
 
 11° 
 
 11 
 
 10 
 
 11 
 
 11 
 
 183° 
 
 11 
 
 18° 
 
 v 
 
 O 1 
 
 H 
 
 11 
 
 less than 
 
 194° 
 
 
132 
 
 SULPHATE OF IRON. 
 
 Ten gallons water, at 194°, will dissolve 100 lbs. more copperas than the 
 same quantity of water will do at 183°, only 11° colder — a fact quite suffi- 
 cient to account for many of the phenomena which exist in the practical 
 operations of the dye-house, when saturated solutions are used without 
 paying attention to the temperature of the solution. At 50° a gallon 
 contains 6 lbs.; at 194°, 37 lbs. 
 
 The sulphate of iron of commerce is not made by dissolving metallic 
 iron in acid, which would be too expensive a process, but from the sulphide 
 ores of iron (iron pyrites). 
 
 We have already, in treating of alum, given an account of how a 
 great quantity of the copperas of commerce is obtained ; but there are 
 numerous and extensive places for manufacturing this salt alone, where no 
 alum is made. The operations are, however, nearly the same as those 
 described for alum. 
 
 Iron pyrites is a bisulphide of iron, FeS 2 ; in 100 parts it has 52 of 
 sulphur and 48 of iron. This compound, when obtained from the older 
 geological formations, undergoes spontaneous decomposition by exposure 
 to the air and moisture ; the sulphur combines with the oxygen of the 
 air, and forms sulphurous acid, which again, in the presence of water 
 and peroxide of iron, takes more oxygen, and becomes sulphuric acid, 
 which combines with the iron forming sulphate. Generally the pyrites is 
 made into large heaps, and set on fire, in the same manner as the alum-shale 
 is treated in the preparatory process of the alum manufacture. This roastmg 
 causes the rapid oxidation of the sulphur, and consequent formation of the 
 sulphate of iron, which is afterwards dissolved out, by passing water through 
 the heaps, and collecting it into tanks. Owing to the excess of sulphur over 
 the iron, there is generally in the solution an excess of acid, with some 
 persulphate of iron, and often small quantities of copper, which would be 
 deleterious. To get rid of this, a quantity of old iron is put into the 
 solution, which takes up the excess of acid at the same time that it pre- 
 cipitates the copper from the solution, and reduces the persalt to the 
 protosalt thus — 
 
 Old iron 
 
 Sulphate of copper.. . ^ _ 
 
 (.Cu _ Copper. 
 
 The reduction of the persulphate of iron to the state of protosulphate 
 may be represented thus — 
 
 Fe.... 
 
 S0 4 ... 
 
 Sulphate of iron. 
 
 Protosulphate. 
 
 Protosulphate. 
 
 Protosulphate. 
 
 The solution is then evaporated to a proper density and crystallised. This 
 method of adding old iron to produce the changes described, not being in 
 
SULPHATE OF IRON. 
 
 133 
 
 all cases adopted, gives rise to some of the varieties of copperas found in 
 the market, concerning which there is great prejudice in the minds of 
 dyers. 
 
 M. Dumas considered the variations in this salt to arise from the forma- 
 tion of a double salt of th e proto and per sulphate, during the decomposition 
 of the pyrites. M. Bansdorff (Records of General Science ) states, that there 
 are three varieties of the protosulphate of iron : the first, greenish-blue, 
 formed from an acid solution free from peroxide; the second, dirty- 
 green, from a neutral solution without peroxide ; and the last, emerald- 
 green, from a solution impregnated with peroxide salt. This we know 
 is consistent with the opinion of practical dyers — that answering the descrip- 
 tion of his second variety being considered the best for general use : but the 
 selection of this particular quality of copperas has led dyers into a fatal 
 prejudice. Sulphate of iron crystallised from a neutral solution, if kept 
 any time, assumes a rusty appearance by absorbing oxygen, and forming 
 a film of peroxide of iron. Now, good copperas having generally this 
 appearance, especially on the surface of the cask when opened, dyers 
 pretty generally entertain the opinion that it is to this redness it owes its 
 superior quality. This, we need hardly say, is an erroneous opinion, 
 
 ! concerning which, Mr. Parkes mentions in his Chemical Essays , that 
 some unprincipled dealers take the advantage to sprinkle lime on the top 
 of the cask to peroxidise the surface, and make the dyers believe that 
 they have got a lot of excellent old copperas. 
 
 As copperas is generally judged of by the colour, a dark-green being pre- 
 ferred, it should be remembered that the worst coloured copperas can be 
 doctored by a solution of common salt or of lime sprinkled upon it, to give it 
 a dark tint; but although this may deceive the eye, it does not improve its 
 bad qualities. 
 
 Copperas, crystallised from solutions of sulphate of alumina, will have 
 an acid reaction, and is not good when used for some of the purposes of 
 ithe dye-house, such as the blue vat, and may be the cause of the light-green 
 watery-coloured copperas found in the market, by it having much more 
 (water of crystallisation than the other. The difference of value between the 
 light-green watery-coloured crystal and the dark-green, is, by experience, 
 about 14 per cent, in favour of the latter. The effects of this will be noticed 
 !more fully when treating of the blue vat. But these results, we believe, to 
 be the reason why a practical dyer, in an excellent treatise upon his trade, 
 [states that there is a bisulphate of iron, and warns the trade against its use.* 
 
 As this watery-looking bluish -green copperas, according to Bansdorff, 
 crystallises from an acid solution, it is probable that the extra proportion 
 of acid which is found in it is owing to a portion of the mother liquor being 
 mechanically combined with the crystals, but not forming an essential ingre- 
 dient in the composition of the salt. And if the salt has been crystallised 
 from sulphate of alumina, this apparent excess of acid will be the same. 
 
 The result of our experience upon the relative value of the light- 
 
 *. Cooper’s Treatise on Practical Dyeing. 
 
134 
 
 SULPHATE OF IRON. 
 
 green watery-coloured copperas over the dark-green, or what are gene- 
 rally termed new and old , is as 21 to 24, or 100 lbs. of best old copperas 
 is worth 114 lbs. of new light-green. In testing, there is always an excess 
 of acid, but not in quantity anything like this difference. As the colour 
 of the crystals of sulphate of iron depends upon the presence of water, 
 and it being well known that copperas, being exposed to the air in a dry 
 place, loses water, this will account for the different proportions of iron 
 which we have often found in the same weight of the salt. It has been 
 already noticed, that of the seven proportions of water which copperas 
 contains, it loses six at 238 p . We took 20 grains of each of the good and 
 bad qualities of copperas, reduced them to coarse powder, and submitted 
 them to a heat of between 305° and 400°, and taking the mean of several 
 experiments, the bad copperas lost 1J grains more than the other, or 
 per cent. — a result which agrees with the experience of the dyer. 
 
 English copperas is considered superior to Scotch. The former is 
 mostly made from pyrites, while the latter is made from alum shale, and 
 is therefore very liable to contain small portions of sulphate of alumina ; 
 then being crystallised from a strong solution of the sulphate of a salt of 
 another metal, it has every chance of being inferior. 
 
 The presence of alumina may be detected by dissolving some of the 
 copperas in water, and boiling the solution, during which a few drops of 
 nitric acid are added to peroxide the iron, which is known by the solution 
 becoming a clear amber colour. Caustic potash is then added in con- 
 siderable excess until the solution is alkaline, and the whole is then 
 boiled for some time, and passed through a filter, upon which the peroxide 
 of iron is retained. The solution contains the alumina. The potash is 
 neutralised by sulphuric acid, and on adding ammonia to this solution, 
 if alumina be present, a flocculent white precipitate is obtained. Other 
 tests for alumina are given under that element. If ammonia be added to 
 the iron precipitate retained upon the filter, if copper be present, the solu- 
 tion passing through will become blue. It is better to test for the presence 
 of copper separately: this is done by dissolving the copperas, as described, 
 peroxidising with acid, adding ammonia instead of potash, and filtering : 
 the slightest trace of copper will tinge the solution blue. Or it may be 
 detected by dissolving a little of the crystals, and putting into the solution 
 a piece of clean polished iron, such as the blade of a knife : when, if any 
 copper be present, it will be precipitated upon the iron in a metallic state. 
 The presence of zinc may be detected in copperas, by taking the ammonia- 
 cal solution which has passed through the filter in testing for copper, and, 
 if no copper be present, pass a stream of sulphuretted hydrogen gas through 
 the solution; the zinc, if there be any present, will give a white precipitate. 
 Copperas obtained from galvanising works has often zinc present, which 
 lowers the value of the salt. The effects of the presence of these salts in 
 some of the operations where copperas is used, will be considered when 
 treating of the blue vat. Magnesia is occasionally found in copperas, but 
 its reactions are not deleterious, further than diluting the salt. 
 
ACETATE OF IRON". 
 
 135 
 
 Chloride of Iron. — Iron is easily dissolved in hydrochloric acid when 
 treated in the same way as was described for dissolving the metal in 
 sulphuric acid, and the product is chloride of iron. 
 
 Two hydrochloric (H 2 Hydrogen gas. 
 
 acid, (,C1 2 
 
 Iron, ....Fe ~~^ r ~~ n > Chloride of iron. 
 
 This salt crystallises in green coloured crystals with four equivalents of 
 water, but with difficulty. The crystals are very soluble in water, and the 
 salt passes rapidly into the perstate. For some purposes of dyeing this salt 
 could be used equally with copperas ; but for others, such as the blue vat, 
 it would not do so well. Moreover, the expense of making it precludes its 
 extensive use in the dye-house. 
 
 Carbonate of Iron. — This salt, as we have already said, exists as an 
 ore ; but it is easily prepared, by adding to a solution of copperas a solu- 
 tion of carbonate of potash or soda. It is a whitish-green coloured 
 precipitate, and is obtained by double decomposition. 
 
 (K 2 ... Sulphate of potash 
 
 Carbonate of potash, (solution). 
 
 Sulphate of iron, ^^-^ Carbonate of iron 
 
 (precipitate). 
 
 This precipitate cannot be dried in the air without losing its carbonic acid 
 and passing into the state of peroxide; but it is soluble in water impreg- 
 nated with carbonic acid. This is the state in which iron is generally held 
 in solution in spring waters, and is hurtful to some dyes. 
 
 Acetate of Iron. — Acetic acid or vinegar acts readily upon iron, 
 dissolving it, and forming the acetate, which crystallises in small green 
 crystals, very rapidly acted upon by the air. This salt is much used in 
 dyeing, and is obtained in solution: it is known as iron liquor, and pyro- 
 lignite of iron, from its being prepared on the large scale with crude 
 wood vinegar. The acetate of iron may be prepared by mixing together 
 acetate of lead and protosulphate of iron. The sulphate of lead is formed 
 and falls to the bottom, and the acetate of iron remains in solution. The 
 pyrolignite of iron is preferable. It is prepared by allowing iron to steep 
 in pyroligneous acid (impure acetic acid, see page 121) for several weeks. 
 As this acid contains a quantity of pyrogenous oils and other impurities, it 
 preserves the iron for a longer time in a state of protoxide than almost any 
 other solvent available in the arts ; hence the decided preference given to 
 it by practical men. We shall often have occasion to refer to this subject, 
 as it is one which is too much neglected, and which produces many 
 serious evils. It may, however, be observed in the meantime, that 
 pyrolignite of iron, used instead of copperas in dyeing black, gives a 
 preferable shade of colour. 
 
136 
 
 NITRATE OF IRON. 
 
 The value of this solution may be taken by evaporating a known weight 
 to dryness, and burning the residue until all organic matters are consumed, 
 when there remains only the iron as a peroxide ; every forty grains of the 
 peroxide will be equal to ninety-six of the acetate of iron in the solution. 
 The operation is very simple, and the percentage of acetate of iron in the 
 solution easily known. The average of good iron liquor ranges about 13-5 
 per cent, of pure protoacetate of iron, the specific gravity being about 
 1*085 = 17° Twaddell. The state of oxidation in which a metal exists, 
 when used as a mordant, ought to be strictly attended to. 
 
 Iron combines in the protostate with oxalic acid, tartaric acid, and 
 indeed with all the acids ; but these salts possess no peculiar advantages over 
 those already described to warrant any extra expense in preparing them. 
 
 Persulphate of Iron. — Persalts of iron are also extensively used in 
 the dye-house. The persulphate of iron may be easily prepared, by boiling 
 a solution of copperas, to which a few drops of sulphuric acid have been 
 added, and, while boiling, adding a very small portion of nitric acid, or any 
 nitrate : red fumes are given off, and the solution becomes of a beautiful 
 amber colour. It is then in the state of a persalt. Chlorate ofjpotash may 
 be used instead of nitric acid or nitrates. The persulphate of iron might 
 be advantageously used for many operations, and be cheaper than the nitrate 
 of iron. 
 
 Nitrate of Iron. — This is the persalt of iron generally used in the 
 dye-house. It is made by putting clean iron into nitric acid, by which it is 
 very quickly dissolved. The iron ought to be added as long as the acid 
 continues to dissolve it; but cautiously, otherwise the action will be so 
 violent as to cause it to boil over. When engaged in this process, care 
 ought to be taken not to breathe any of the fumes which come off, as they 
 are very destructive to health. The reaction which takes place between the 
 acid and the iron may be expressed as in the table below, which we intro- 
 duce by remarking, that in dissolving iron in sulphuric or hydrochloric 
 acid, there is merely a substitution of the iron for the hydrogen (see page 
 26) ; but with nitric acid a different range of affinities takes place — a 
 proportion of the nitric acid is broken up, producing the following 
 arrangement : — 
 
 One nitric acid, 
 
 hno 3 
 
 Lh 
 
 Three proportions J 3 H... 
 
 nitric acid ( 3 N0 3 
 
 Two proportions iron 2 Fe.. 
 
 Or 4 HN0 3 + 2 Fe = 
 
 Binoxide of nitrogen. 
 
 2 Water H 2 0. 
 
 Nitrate of iron. 
 2Fe3N0 8 + N0 2H 2 0. 
 
NITRATE OF IRON. 
 
 137 
 
 The binoxide of nitrogen, or nitric oxide, is the gas passing off ; but it 
 instantly combines with more oxygen, and forms peroxide of nitrogen. 
 
 Nitrate of iron alone dyes a buff or nankeen colour, which is pro- 
 bably the easiest dyed of any of the colours, and is, at the same time, 
 very permanent. The process only requires that a little of this salt be put 
 into water, and that the goods be immersed in the solution for a few 
 minutes, then washed in clean water and dried. Passing them through a 
 weak soap solution softens the goods, and gives clearness to the tint. But 
 the particular use of this salt is for Prussian blue. The goods are first 
 dyed buff by the salt of iron, then thoroughly washed and put into a very 
 dilute solution of ferroprussiate of potash, made acid by a few drops of 
 sulphuric acid ; they are washed from this in clean water, to which a little 
 alum has been added. (This is only for light blues on cloth, but for dark 
 blues and for yarn the proper methods will be given hereafter.) We have 
 known many attempts made to substitute copperas for nitrate of iron in 
 dyeing Prussian blue with the yellow prussiate, but need hardly say they 
 were unsuccessful. A knowledge of the nature of these salts (see page 98) 
 shews that protosalts of iron give only a greyish colour with yellow 
 prussiate of potash ; but page 100 shews that with red prussiate of potash 
 copperas is a better mordant than nitrate of iron, as the red prussiate gives 
 a dark blue with the protosalts, and only a greenish grey with the persalts 
 of iron. 
 
 The preparation of nitrate of iron ( killing iron ) is apparently one of 
 the most simple operations of the dye-house, as all that is required is to 
 place metallic iron into nitric acid ; but the practical dyer often experiences 
 difficulties which he cannot account for, and which alter materially his 
 shades and colours. Sometimes, as we have already noticed, the iron seems 
 not to be acted upon ; at another time the action is so rapid that there is a 
 difficulty in preventing the liquid boiling over. When the acid is a little 
 diluted, and the iron is added in small pieces, the action is violent, and 
 there is often formed a brown turbid clay-looking solution. Colours dyed 
 by the iron in this state are never so brilliant as when the liquor is clear. 
 We have seen solutions of this sort diluted largely with water and allowed 
 to settle, and the clear only used ; but this is tedious, and not good after all. 
 The best means of improving this mordant when it thickens or becomes 
 turbid is to remove all metallic iron, add a little nitric or muriatic acid, and 
 apply heat. 
 
 When the nitric acid is not diluted, and the iron dissolves freely, when 
 the acid is saturated with iron, if the remaining metallic iron is not removed, 
 it continues to dissolve by the reaction of the nitrate of iron upon it, thus — 
 
 One part nitrate 
 
 of iron NO s 
 
 I no 3 
 
 Uo 3 
 
 One part iron Fe... 
 
 Protonitrate. 
 
 Protonitrate. 
 
 . Protonitrate. 
 
138 
 
 NITRATE OF IRON. 
 
 This protonitrate rapidly imbibes oxygen, passes into the pernitrate, and 
 in so doing liberates a portion of oxide of iron, which collects at the 
 bottom of the vessel, and accumulates so rapidly that the iron solution 
 is soon converted into a brown paste. This can be avoided by taking 
 out the iron when the acid is saturated, and before this deposit begins. 
 The addition of a little acid and heat re-dissolves this oxide ; or a little 
 sulphuric or hydrochloric acid, also dissolves it, and forms an excellent 
 mordant. 
 
 A still more remarkable circumstance often occurs: the iron being 
 placed in the acid, and action going on favourably, after a few hours, par- 
 ticularly if the weather be cold, the solution is observed to have a greenish- 
 yellow colour, and the vessel is found to be half filled with crystals of a 
 light-yellow tint. Although these crystals, when dissolved in water, or though 
 the solution above the crystals, may be used for dyeing, they give varieties of 
 quality differing from the usual iron solution, which often seriously disturb 
 the method of the dye-house. The true nature of the crystals is not well 
 understood, and it is difficult to get at their examination, as they are very 
 deliquescent, dissolve easily in water, and even in their own water of 
 crystallisation, by a slight elevation of temperature. When put upon 
 blotting paper they are decomposed, and the paper imbibes much of the iron. 
 We long thought that they were caused by the formation of ammonia in 
 dissolving the iron, but experiments have failed to shew the slightest trace 
 of ammonia. The analysis of these crystals by J. M. Ordway gave by the 
 old notation 3 nitric acid, 1 peroxide iron, and 18 water = 3 NOs-}-Fe 2 
 0 3 -)-18 HO. The same author has examined nitrates of iron of different 
 qualities, and states that nitric acid combines definitely with various pro- 
 portions of peroxide of iron and water, forming what he terms basic nitrates, 
 varying from 3 acid and 1 peroxide iron, to 3 acid and 2, 3, 6, 8, 12, 15, 18, 
 and 24 peroxide of iron, with various definite quantities of water, giving an 
 interest to this salt of the highest sort, and amply accounting for the great 
 differences experienced in its use for dyeing; and also for the ease with 
 which peroxide of iron is fixed upon the fabric when put into this salt : the 
 basic salt being decomposed, and a portion of the oxide of iron left upon or 
 within the fibre. There are many other phenomena observed in working 
 with these salts, which we will yet have occasion to notice. We have 
 already noticed the action of light on this salt (page 13). 
 
 Any other persalt of iron may be formed by adding ammonia, carbon- 
 ate of soda, or potash, to the nitrate of iron solution, so long as a precipi- 
 tate is formed, washing the precipitate, by repeatedly filling the vessel which 
 contains it with water, allowing it to settle, and decanting off the clear, 
 then adding to the precipitate the acid of the salt which is wanted. The 
 application of heat assists the solution of the precipitate in the acid. By 
 these means peracetate, peroxalate, pertartrate, &c., may be obtained either 
 for practical use or experiments. 
 
 The following is the reaction of different substances upon the pro and 
 per salts of iron : — 
 
COBALT. 
 
 139 
 
 Protosalts. — Potash, soda, and ammonia give at first a grey-white 
 precipitate, passing into green, then bluish, and which, by exposure, finally 
 becomes brown. 
 
 Carbonates of these alkalies produce precipitates, which pass through 
 the same changes as the alkalies themselves. 
 
 Yellow prussiate of potash... A grey- white precipitate, which by ex- 
 
 posure becomes blue. 
 
 Red prussiate of potash An immediate dark-blue precipitate. 
 
 Solution of galls A blue-black, not changed by standing. 
 
 Persalts of Iron. — Alkalies, and carbonates of the alkalies, all produce 
 dark-brown precipitates. 
 
 Yellow prussiate of potash... An immediate dark-blue precipitate. 
 
 Red prussiate of potash No precipitate, but the solution becomes 
 
 green. 
 
 Solution of galls Black, passing to brown, by standing. 
 
 The difference between the action of red and yellow prussiates and 
 galls with these salts will be remarked. 
 
 Cobalt (Co 58-7). 
 
 Cobalt generally occurs in Nature in combination with arsenic and 
 sulphur, and accompanied by other metals. The mineral in which it occurs 
 was long known to miners, and was called by them Tcobalds, or evil spirit of 
 the mines, because its appearance often deceived them by giving a favour- 
 able impression of mines which turned out erroneous, the cobalt being 
 taken for something else. Its distinct character as a metal was discovered 
 in 1733. Its oxide has long been extensively used for giving a blue colour 
 to glass and porcelain. As a metal it is brittle, of a reddish-grey colour, 
 and a little more flexible than iron. It has two oxides similar to iron — 
 
 Protoxide, CoO. 
 
 Peroxide, . Co 2 0 3 . 
 
 But there is no persalt of cobalt known equivalent to the peroxide. 
 
 Cobalt is easily dissolved in either hydrochloric or nitric acids, and forms 
 pink-coloured solutions which produce crystals of a beautiful red colour. 
 Solutions of these salts form sympathetic inks. By writing upon clean 
 paper with one of these solutions, the writing is invisible when dry ; but by 
 heating the paper before a fire, the writing becomes blue, and disappears 
 again on cooling. If the heat applied be too strong, the writing becomes 
 black and permanent — a significant fact to the dyer. Cobalt does not dis- 
 solve easily in sulphuric acid; but a sulphate may be prepared by adding 
 sulphuric acid to the oxide or carbonate, which is formed by adding a car- 
 
140 
 
 SULPHATE OF NICKEL. 
 
 bonate or caustic alkali to the nitrate or hydrochlorate of cobalt. The 
 sulphate salt has also a pink colour, but is not so generally used as the 
 others. Salts of any of the acids may be prepared by dissolving the oxide 
 or carbonate. They are all affected by heat in the manner described. 
 
 Some of these salts might be very usefully employed in dyeing were 
 they obtained at a sufficiently low cost ; however, they are progressively 
 becoming cheaper, and may therefore ere long be made available in the 
 dye-house. 
 
 A preparation of cobalt is used in bleaching, as smalt blue. It is a 
 compound of oxide of cobalt and alumina, prepared by mixing a solution 
 of a salt of cobalt and alum, and precipitating them together by an alkaline 
 carbonate, as carbonate of soda, drying the precipitate, and subjecting it 
 to a red heat. The process gives a beautiful blue mass, which is ground to 
 an impalpable powder, and mixed commonly with some carbonate of lime 
 (chalk). Salts of cobalt give the following reactions with other sub- 
 stances : — 
 
 Potash, soda, and ammonia... A green colour by a little exposure. 
 
 Carbonates of the alkalies Reddish precipitates, which become blue 
 
 by boiling. 
 
 Phosphate of soda Blue precipitate. 
 
 Yellow prussiate of potash... .Green precipitate, which changes to grey. 
 
 Red prussiate of potash Reddish-brown precipitate. 
 
 Sulphides of the alkalies Black precipitates. 
 
 The slightest trace of cobalt may be detected by the blowpipe, by 
 fusing a little borax, and adding a little of the substance suspected to con- 
 tain cobalt: if it be really present, it communicates to the borax a blue 
 colour, more or less intense. 
 
 Nickel. (M 58-7.) 
 
 Nickel occurs in Nature combined with arsenic, iron, cobalt, and sul- 
 phur. It was discovered in 1751. Isolated, it is a silver-white metal, 
 ductile and malleable, and requires a heat nearly equal to that of iron to 
 melt it. It is much used in the arts for alloying with other metals. It is 
 the principle constituent of German silver. Nickel combines with oxygen 
 in two proportions: 
 
 Protoxide, ...... NiO. 
 
 Peroxide, Ni 2 0 3 . 
 
 There are no salts of nickel equivalent to the peroxide known. 
 
 Sulphate of Nickel. — Sulphuric acid dissolves nickel with difficulty. 
 When the sulphate is required, the acid is applied to the carbonate or 
 
ZINC. 
 
 141 
 
 oxide of the metal ; in this state it is easily dissolved, and forms a beautiful 
 green-coloured solution. 
 
 Chloride of Nickel. — Hydrochloric acid, when dilute, dissolves 
 nickel, and forms a chloride ; the solution is emerald green. 
 
 Nitrate of Nickel. — Nitric acid dissolves nickel easily, and may be 
 called its true solvent: the product is the nitrate, of which the solution is 
 also emerald green. All these salts crystallise. 
 
 Carbonate of Nickel. — This salt is prepared by precipitating the 
 nitrate by a carbonated alkali, as carbonate of soda or potash. It is a 
 greenish coloured precipitate. The common means of preparing the salts 
 of nickel is by dissolving in nitric acid, then precipitating by carbonate of 
 soda, and washing the precipitate ; by adding the required acid to the pre- 
 cipitate it is dissolved. The acetate, or oxalate, or any of the other salts, 
 may easily be prepared in this way. The use of any of these salts in the 
 dye-house is very limited. Their solutions are precipitated as follows : — 
 
 Alkalies, . . . . 
 
 Ammonia, in excess, . 
 Carbonate of the alkalies, . 
 Yellow prussiate of potash, . 
 Red prussiate of potash, 
 Solution of galls, . 
 
 Phosphate of soda, 
 
 Sulphide of the alkalies, 
 
 An apple-green precipitate of hydrated 
 oxide, insoluble in excess. 
 
 Blue solution. 
 
 Green precipitate. 
 
 Greenish-white precipitate. 
 Yellow-green precipitate. 
 
 No precipitate. 
 
 White precipitate. 
 
 Black precipitate. 
 
 Zinc. (Zn. 65-2.) 
 
 Zinc was discovered in the sixteenth century. It is very abundant in 
 Nature in combination with sulphur, and with carbonic acid. With the 
 former, it is the ore called blende, or black jack ; with the latter, it is 
 calamine. Zinc is a white metal with a shade of blue, brittle, and of a 
 crystalline structure. When heated from the boiling point of water to 
 300°, it is ductile, and admits of being rolled into sheets, in which state it 
 has become a most useful metal in the arts. At a red heat it rises into 
 vapour, and takes fire in air, burning with a white flame. It is much used 
 along with copper for making the common alloy known as brass. 
 
 Zinc combines with oxygen in several proportions ; but the only one 
 of its oxides which has been studied is the protoxide = ZnO. The salts 
 formed are the protosalts, equivalent to this oxide. 
 
 Protoxide of zinc may be obtained either by burning the metal in the 
 
142 
 
 NITRATE OF ZINC. 
 
 air, or by precipitating it by an alkali from its acid solutions. It forms a 
 white powder, which is soluble in all the caustic alkalies. 
 
 Chloride of Zinc. — Hydrochloric acid acts rapidly upon zinc, evolv- 
 ing hydrogen gas — thus 
 
 Two hydrochloric CH 2 ... Hydrogen gas. 
 
 acid, (O2... — 
 
 Zinc, Zn... Chloride of zinc. 
 
 It crystallises in white crystals, which are very deliquescent, and often 
 used on account of this property for keeping substances damp. It is even 
 said to be employed by tobacconists for keeping snuff and tobacco moist — 
 a dangerous and most reprehensible practice, if true. It is now very 
 extensively used for soldering instead of rosin. 
 
 Sulphate of Zinc. — This salt is easily prepared by putting zinc into 
 sulphuric acid slightly diluted : the action is 
 
 Sulphuric acid, —Hydrogen gas. 
 
 Zinc, Zn... ^ Sulphate of zinc. 
 
 It crystallises in white-coloured crystals, which contain seven proportions 
 of water of crystallisation, and dissolve in two and a half times their weight 
 of cold water. It is known in commerce as white vitriol and white copperas , 
 and is produced as a by-product in the soldering of platinum vessels, and 
 by plumbers in burning together lead surfaces. Operations of this kind are 
 done by the flame of the oxyhydrogen blowpipe, for which the hydrogen 
 required is prepared by zinc and sulphuric acid, and thus the sulphate be- 
 comes a product. It is also obtained as a by-product in Electro-Metallurgy 
 from the galvanic batteries. 
 
 Nitrate of Zinc. — This salt is easily prepared by acting upon the 
 metal with nitric acid ; it is a crystalline salt, very deliquescent, but not 
 much used. 
 
 Acetates, oxalates, and salts of such milder acids may be prepared 
 either by digesting the metal in the acids, or by acting upon the oxide or 
 carbonate. The salts of zinc are not much used in the dye-house; the 
 precipitates formed from them are nearly all white ; but the sulphate is 
 used in several operations, where its elements may act an important part 
 without affecting the tint, as in the operations of dyeing chrome yellows , &c. 
 It is also used by calico-printers in some of the operations of discharging. 
 
 The salts of zinc act towards other subtances as follows : — 
 
 Potash, soda, and ammonia, . White precipitate, easily dissolved in 
 
 an excess of the alkali. 
 
INDIUM. 
 
 143 
 
 Carbonates of the alkalies, 
 
 Yellow prussiate of potash, 
 Red prussiate of potash, . 
 
 Solution of galls, 
 
 Sulphides of the alkalies, 
 Chromic acid, 
 
 White precipitate, not soluble in ex- 
 cess, but soluble in caustic alkalies. 
 White precipitate. 
 
 Yellowish-red precipitate; fades in 
 the air. 
 
 No precipitate. 
 
 White precipitate. 
 
 A purple-brown precipitate. 
 
 Cadmium. (Cd. 112.) 
 
 This metal was discovered in 1818 ; it is very rare, found only in small 
 quantities, and sometimes combined with zinc. The metal somewhat 
 resembles tin in colour ; it is also soft and flexible, and makes a crackling 
 noise when bent. It melts easily, and passes off as a gas at a heat of about 
 600°. It combines with oxygen in equal proportions, forming the pro- 
 toxide (CdO), which has an orange colour, and is easily obtained by 
 burning the metal in air, or by precipitation from acid solution as an 
 hydrate. When prepared in this way, it is white, and has one proportion 
 of water combined with it. This oxide is soluble in ammonia, but not in 
 soda or potash. 
 
 Cadmium is acted upon like zinc, both by sulphuric and hydrochloric 
 acids, and forms crystallisable salts. Nitric acid acts readily upon the 
 metal to form the nitrate, which is crystallised with difficulty. All these 
 salts give white- coloured crystals. The salts of the milder acids, as the 
 acetate, the oxalate, &c., may be obtained by dissolving the precipitated 
 oxide or carbonate in the particular acid. 
 
 Potash and soda, and their carbonates, give white precipitates, not 
 soluble in excess. 
 
 Ammonia — white precipitate, soluble in excess. (The oxide and car- 
 bonate, precipitated by the fixed alkalies, are all soluble in ammonia.) 
 
 Yellow prussiate of potash, . 
 Red prussiate of potash, 
 Solution of galls, . 
 
 Sulphides of the alkalies, 
 
 White precipitate.. 
 
 Yellow precipitate. 
 
 No precipitate. 
 
 Beautiful yellow precipitate. 
 
 Indium. (113-4.) 
 
 One of the recently discovered metals, found in small quantities 
 occasionally associated with zinc. It is a white soft metal. It is one of 
 those metals discovered by the spectroscope. When heated in a colourless 
 gas flame, it gives two strong lines in the indigo portion of the spectrum 
 — hence its name. It is very rare, and not yet known in the arts. 
 
144 
 
 SULPHATE OF COPPER. 
 
 Copper. (Cu 63-1.) 
 
 This is a very abundant and useful metal, and was known in the 
 earliest times. It is found in Nature in great quantities in combination 
 with sulphur, oxygen, and carbonic acid ; and is separated from these 
 combinations by various processes of roasting and fusing. Copper is of a 
 red colour; is very malleable and ductile, and only inferior to iron in 
 tenacity. It requires a heat of about 1900° to fuse it. It combines with 
 oxygen in two proportions, namely — 
 
 Suboxide, or red oxide, CU 2 O. 
 
 Protoxide, or black oxide, . . . . CuO. 
 
 The suboxide is of a reddish-brown colour, which is not changed by the 
 air. If acted upon by dilute acids, a protosalt is formed, and in stroug 
 hydrochloric acid there is formed a subchloride = CuCl. This is a greenish 
 or nearly colourless solution. This chloride is precipitated by dilution 
 with water ; as a white precipitate when exposed to air it becomes green. 
 If a portion of sub oxide be put into a stoppered bottle with ammonia, it is 
 dissolved ; the solution is colourless at first, but by admitting air it is 
 oxidised, and the solution becomes blue. 
 
 Protoxide of Copper is black, and is formed upon the surface of 
 metallic copper when brought to a red heat and exposed to the air ; or it 
 may be obtained by exposing the carbonate, acetate, or nitrate, to a red 
 heat. Alkalies added to solutions of copper precipitate the oxide as a 
 hydrate of a blue colour, , which becomes black by boiling. Oxide of 
 copper dissolves readily in ammonia, and gives a deep blue-coloured 
 solution. 
 
 Copper combines with nearly all the acids, and the salts produced are 
 generally blue or green. Sulphuric acid, when cold, dissolves copper 
 slowly, but at a boiling heat it acts upon it readily, a portion of the acid 
 suffering decomposition, as under : — 
 
 fS.... 
 
 , o.... 
 
 One proportion of q 
 sulphuric acid*> q 
 decomposed | q 
 
 [h 2 ... 
 
 One proportion of { SO .. 
 
 sulphuric acid ( H 2 ... 
 One prop, of copper.. Cu.... 
 
 Sulphurous acid gas. 
 
 .Water. 
 
 Water. 
 
 .Sulphate of copper. 
 
 Sulphate of Copper yields deep blue crystals, containing five pro- 
 portions or equivalents of water, four of which are given off by heating 
 the crystals to 212°, at which temperature they become white. They are 
 soluble in four times their weight of cold water, and in twice their weight 
 
CHLORIDE OF COPPER. 
 
 145 
 
 of boiling water. The salt is prepared on the large scale, in the same 
 manner as the sulphate of iron ; that is, from the sulphides of the metal. 
 Great quantities of it are produced by the metal-workers in Birmingham 
 and elsewhere, in their cleaning and bronzing operations, which are effected 
 by the action of acids upon copper or its alloys. As obtained in com- 
 merce, it is very impure, and is often contaminated with iron — a very 
 injurious ingredient for most of the purposes to which this salt is applied 
 in the dye-house. This impurity can be detected by dissolving a little of 
 the salt in pure water, and adding ammonia in excess ; on filtering through 
 paper, and washing the filter, the iron will be obtained as a brown pre- 
 cipitate of peroxide. If the salt contains much iron, it ought to be rejected . 
 Zinc is often present, but it has no deleterious effects further than in 
 lessening the value of the salt. Sulphate of copper is known in commerce 
 and in the dye-house as blue vitriol , Roman vitriol , and blue-stone. 
 
 Nitrate of Copper. — Nitric acid dissolves copper easily, forming 
 the nitrate ; the action is similar to that by which the nitrate of iron is 
 produced ; but we give here the old notation, and we suggest that the 
 reader compare this with that given for iron, page 135. 
 
 One proportion of 
 
 nitric acid 
 
 NO 5 + HO, or 
 
 no 6 + h 
 
 Three proportions of 
 copper 
 
 Binoxide, or nitric oxide. 
 
 H ^ 
 
 
 Water. 
 
 3 N0 6 
 
 3 H... ^ 
 
 
 ^ 3 Water. 
 
 3 Cu 
 
 
 ^ 3 Nitrate of copper. 
 
 Formula by newnotation, 8 HN0 3 -(-3 Cu = 2N0-f-3(Cu2N0 3 ) -J-4H 2 0. 
 
 It may be prepared in the dye-house by adding a solution of nitrate 
 of lead to a solution of sulphate of copper, so long as a precipitate is 
 
 formed. 
 
 Nitrate of copper crystallises in deep blue crystals, which deliquesce 
 in the air, and are accordingly very soluble in water. The salt acts rapidly 
 upon tin ; if a small crystal be crushed, slightly moistened, and wrapped in 
 tinfoil, combustion takes place by the rapid oxidation of the tin. The salts 
 of copper are useful for oxidising vegetable matters in solution, and are 
 sometimes used for that purpose in the dye-house. 
 
 Chloride of Copper is made by digesting oxide of copper in hydro- 
 chloric acid, by which a double decomposition takes place, as follows : — 
 
146 
 
 LEAD. 
 
 Two hydrochloric acid, 
 Oxide of copper, 
 
 Water. 
 
 Chloride of copper. 
 
 The solution of this salt is green, but it crystallises from this solution in 
 blue-coloured crystals.. It is prepared in the dye-house by mixing a hot 
 solution of chloride of calcium with sulphate of copper ; lime precipitates 
 as sulphate, and the chloride of - copper remains. 
 
 Acetate of Copper ( verdigris ) is prepared by exposing sheets of 
 copper to the action of acetic acid (vinegar), sometimes in solution, but 
 more commonly in vapour. The salt is obtained in beautiful dark-green 
 crystals ; in this state it is a subacetate, having one acetic acid to two of 
 copper. Acetic acid combines with copper in various proportions, and the 
 verdigris of commerce is often composed of several salts, not by adultera- 
 tion, but formed in the process of manufacture. 
 
 Oxalate of Copper is of a light-green colour, and is prepared by 
 digesting oxide of copper in oxalic acid. 
 
 Arseniate and the Arsenite of Copper are salts of a light-green 
 colour, forming the dyes called arsenic greens — blue-stone sages or Scheele's 
 green — in dyeing which the goods are passed through strong solutions of 
 an alkaline arseniate and copper. This process of dyeing is dangerous, 
 and the winding of the yarns, and other operations that follow, are more 
 so, and produce much serious mischief to the operatives. Green wall 
 paper is often coloured with this dye, which is very hurtful to the health 
 of the occupants of the house. 
 
 Copper salts produce the following reactions: — 
 
 Potash and soda,..., .Greenish -blue precipitates, become black with 
 
 boiling. 
 
 Ammonia, Deep-blue liquid. 
 
 Carbonate of alkalies, Green precipitate. 
 
 Yellow prussiate of potash, ...Dark-brown precipitate, becomes green when 
 
 boiled. 
 
 Ked prussiate of potash,. ...... Yellow-green precipitate. 
 
 Solution of galls, Brown precipitate. 
 
 Sulphides of the alkalies, ..... Black precipitates. 
 
 Lead (Pb 207). 
 
 This metal exists abundantly in Nature in combination with sulphur, 
 forming galena, from which it is separated by exposing the ore to a red 
 
PROTOXIDE OF LEAD. 
 
 147 
 
 i heat; the sulphur becomes oxidised, some of it passes off as sulphurous 
 | acid, and part is converted into sulphate of lead ; the heat is then raised, 
 
 | which causes a chemical reaction between the sulphate and sulphide, and 
 I the metal becomes reduced, and runs off by a channel prepared for it. 
 
 Lead has a bluish-grey colour, is soft and very malleable; it does 
 aot oxidise readily in the air, except at the water line, when it is partially 
 immersed in that fluid, and more rapidly still when the water is soft and 
 pure. Hence lead vessels should not be used to hold water for domestic 
 use, as the oxides of lead are all very poisonousL 
 
 Lead combines with oxygen in various proportions. 
 
 Suboxide of Lead is the greyish-blue crust formed upon the surface 
 l of lead exposed to the air, and consists of two equivalents of lead and one 
 pf oxygen, Pb 2 0. It may be prepared artificially by burning oxalate of 
 I ead in a retort ; the suboxide remains as a dark-grey powder. 
 
 | Protoxide of Lead consists of lead and oxygen in equal propor- 
 tions = PbO. It may be obtained by exposing metallic lead at a red 
 qeat to a current of air; the oxygen of the air combines with the lead, and 
 i'orms with it a semi-fluid mass. As it cools, it crystallises in concretions 
 of a greenish-yellow colour. It is obtained on the large scale by cupella- 
 
 I lon — a process of fusion to which lead is subjected in the process of 
 Extracting the admixture of silver it commonly contains. The process is 
 Conducted as follows:— A quantity of lead is put upon a flat vessel made 
 
 | )f bone ashes ( burned bones) placed in a furnace; when the lead is melted, 
 t strong current of air is blown upon the surface, which rapidly oxidises 
 jhe metal; at the same time, the force of the eurrent blows the oxide off, 
 vhich runs over the side of the vessel like water. The silver, not being 
 ||:apable of oxidation, by this means is ultimately left pure upon the bottom 
 )f the vessel. Fresh silver lead is continually added, until the silver remain- 
 jag nearly fills this bone-ash vessel, which is technically termed a cupel. 
 
 When the protoxide of lead is kept for some time, it falls into a brick- 
 led scaly crystalline powder, known in commerce as litharge. This is the 
 principal oxide from which the salts of lead are prepared ; but it is gene- 
 tally to some extent contaminated with iron, copper, and red lead, and is 
 Iso subject to much intentional adulteration. Litharge of good quality 
 ossesses a crystalline lustre, and is completely soluble by digestion in 
 itric acid. The amount of adulteration, if it be brick dust, may thus be 
 | scertained, as it remains insoluble, and by adding ammonia to the solution 
 he lead is precipitated; if iron be present, the precipitate will have a 
 rown colour ; if copper, the solution will be blue, but none of these are 
 i eleterious to the dyes for which lead salts are generally used. The 
 ; rotoxide of lead is also obtained by adding a caustic alkali to a solution 
 f a salt of lead ; the oxide is precipitated as a white powder, soluble in an 
 jxcess of caustic alkali, and also in solutions of the alkaline earths, as lime, 
 ft r ith which it forms compounds more or less soluble. 
 
148 
 
 ACETATE OF LEAD. 
 
 Peroxide of Lead consists of two equivalents of oxygen and one of 
 lead=Pb0 2 . It may be obtained by digesting litharge in a boiling 
 solution of chloride of lime (6 leaching powder). It is a powder of a dark- 
 brown colour, and is not used for preparing any salts of lead. 
 
 What is termed the fourth oxide of lead consists of Pb 3 0 4 ; but this 
 is not generally considered to be a direct combination of oxygen and lead 
 in these proportions, but a mixture of the second and third oxide just 
 described, in the proportion of two of the protoxide to one of the peroxide, 
 2Pb0-j-Pb0 2 , which maybe separated by digestion in dilute nitric acid, 
 the acid combining with the protoxide, and liberating the peroxide which 
 remains undissolved. Whether the view we have stated of its constitution 
 be correct or not is not very important, as this oxide is not much used in 
 the dye-house. It is known in commerce as red lead or minium. 
 
 Carbonate of Lead {White Lead) is formed when carbonate of soda is 
 added to a salt of lead. It is prepared on the large scale by exposing thin 
 sheets of lead to the vapours of vinegar: the acid is decomposed and 
 forms carbonic acid, which combines with the lead. This salt is some- 
 times used for preparing salts of lead, by dissolving it in the acid the salt 
 of which is required. 
 
 Nitrate of Lead is prepared by dissolving litharge or metallic lead 
 in dilute nitric acid, and then concentrating the solution by slow evapora- 
 tion, when the salt is obtained in a crystalline form ; it is white and 
 generally opaque, and soluble in 7^ parts of cold water. The nitrate of 
 lead, when prepared in this way, contains one proportion of oxide and 
 one of nitric acid; but by boiling the salt for some time over litharge, the 
 acid combines with two, three, or even six proportions of lead, forming 
 what are termed basic salts. This fact has been known to practical dyers 
 for many years, and is made available for the purpose of dyeing orange 
 colours and dark shades of yellow. 
 
 Acetate of Lead {Sugar of Lead ) may be obtained by exposing 
 metallic lead to the action of acetic acid, either as a liquid or as a vapour, 
 and to the air; a portion of the acid is decomposed, and carbonate of lead 
 is formed, which is easily decomposed by another portion of the acid; 
 the latter combining with the lead forms acetate of lead, and the carbonic 
 acid is evolved. 
 
 Acetate of lead is prepared extensively by a variety of modes. One 
 is by immersing a number of sheets of lead in vinegar, so arranged 
 that the uppermost sheets are exposed to the action of the air. When 
 they become covered with the crust of carbonate, they are shifted to the 
 bottom of the vat, where the acid decomposes the carbonate and forms 
 acetate, while the succeeding sheets are being exposed to the same course 
 cf action. 
 
 Another process is to expose sheets of lead to the vapour of vinegar; i 
 
ACETATE OF LEAD. 
 
 149 
 
 the carbonate formed is collected and immersed in strong vinegar. In 
 both these processes, when the acid appears to be saturated, or when it 
 ceases to decompose the carbonate, the solution is drawn into proper 
 vessels and allowed to crystallise. 
 
 Another process is to dissolve litharge in strong vinegar to saturation. 
 This is done by gradually sprinkling the litharge in a vessel of vinegar 
 subjected to a boiling heat; the vinegar is constantly stirred, to prevent 
 the adhesion of the litharge to the bottom and sides of the boiler. When 
 a sufficient quantity is dissolved, a moderate quantity of cold water is 
 poured into the solution, reducing it a little below the boiling point, and it 
 is allowed to settle ; the clear fluid is then drawn off into a separate vessel 
 and allowed to crystallise. If the solution be coloured, it is whitened 
 by filtration through bone black. Common unrectified wood vinegar, or 
 pyroligneous acid, is much used for the preparation of acetate of lead for 
 the dye-work. It is known in the dye-house by the appellation of brown 
 sugar. 
 
 Basic salts, or subacetates, are made by boiling common acetate of 
 lead with litharge. The tribasic acetate, a combination of three of lead 
 to one of acid, is the best salt for dyeing orange, deep yellow, and amber. 
 It is prepared in the dye-house by boiling a solution of sugar of lead with 
 litharge, and adding to this a little lime. The proportions, however, vary 
 in different dye-houses. Those which ought to be employed to produce 
 the tribasic acetate are — six parts of crystallised acetate of lead, eight of 
 litharge, and thirty of water, boiled till the litharge is dissolved. This 
 solution renders red litmus blue. The addition of small quantities of lime 
 causes a loss, as the lime combines with part of the acetic acid forming 
 acetate of lime, which, if these proportions have been used, would prevent 
 some of the litharge from being dissolved. If the mixture be not long enough 
 boiled, or if the proportion of litharge be too small, the addition of lime 
 insures the conversion of the acetate of lead into the tribasic state, though 
 it is to be observed that this will be at the expense of a portion of the 
 lead intended for producing the colour. We have experienced much 
 annoyance from this source; and it is well known in the trade, that when 
 the lead is hastily prepared for orange, it is a cause of great anxiety, and 
 the colour obtained is frequently defective. As this is an important point 
 in the economy of the dye-house, both in time and material, we shall 
 explain the practical view of the matter. If the proportions recommended 
 above be used, the following is the result : — The 6 pounds of acetate of 
 lead are composed of 4 lbs. oxide of lead and 2 lbs. acetic acid ; but when 
 the 8 lbs. of litharge are dissolved, or, as dyers say, taken up, the tribasic 
 salt will consist of 12 lbs. of oxide of lead and 2 lbs. of acetic acid — that 
 is, every ounce of acid holds in combination 6 ounces of oxide of lead. 
 Now, if a little lime, as we have often remarked, be put in along with the 
 litharge, the result will be as follows : — Suppose that 50 lbs. of cotton are 
 to be dyed orange, and that it consumed the 6 lbs. acetate of lead prepared 
 as now stated, to give it a good colour. If ounce of lime be mixed 
 
150 
 
 CHLORIDE OF LEAD. 
 
 with this, it will combine with 3 ounces of acid: in this way 36 ounces of 
 oxide of lead are not taken up, and are therefore ineffective in the pro- 
 duction of the colour; while at the end of the process, the dyer is surprised 
 to find his colour poor. We may notice that lead in the basic state is not 
 held in combination by a very great affinity, and thus a very little counter- 
 active influence precipitates it. The presence of sulphates or carbonates 
 in the water, which almost all water contains, precipitates the lead; hence 
 the reason that often, when the clear acetate solution is poured into a tub 
 of water, the contents become milk-white by the formation of an insoluble 
 carbonate or sulphate. The lead is all lost for the time, as it is rendered 
 insoluble and useless as a dye.- Every ounce of carbonate renders useless 
 five ounces of lead. The softest water should be used for the lead solu- 
 tion, as, for example, the condensed steam from an engine. Breathing 
 through the solution of subacetates produces a precipitate of lead car- 
 bonate. When much lime is added, it dissolves the lead, and forms a 
 mordant quite as good, if not superior to that described, as we will have 
 occasion more fully to indicate when we come to treat of the processes for 
 dyeing oranges and yellows. Alkaline salts of lead, i.e., oxide of lead 
 dissolved in alkalies, are now becoming more generally used than the acid 
 salts, and are superior for most purposes. 
 
 Sulphate of Lead. — Sulphuric acid, when hot and concentrated, 
 dissolves lead ; the sulphate formed is precipitated by dilution. It is an 
 insoluble white powder ; it is formed by adding a solution of any sulphate 
 to any salt of lead. It is formed in making acetate of alumina. 
 
 Chloride of Lead. — Lead dissolves slowly in hydrochloric acid, 
 forming a chloride which requires 135 times its weight of cold water to 
 dissolve it. Several subchlorides of lead are also capable of being formed, 
 but they are nearly all insoluble in water. Oxide of lead is soluble in 
 caustic soda, potash, and lime, and is used as a mordant in dyeing green 
 by chrome. 
 
 All the soluble salts of lead are poisonous, and have a sweetish taste. 
 Their reactions with other substances are as follows : — 
 
 Soda and potash give . 
 Lime, ....... 
 
 Ammonia, . 
 
 Carbonates of alkalies, 
 
 Oxalic acid, 
 
 Yellow prussiate of potash, 
 Red prussiate of potash, 
 Solution of galls, 
 
 Chromates of potash, . 
 Iodide of potassium, . 
 Sulphides of the alkalies, 
 
 White precipitates, soluble in excess. 
 White precipitate, soluble in excess. 
 White precipitate, insoluble in excess. 
 White precipitates, insoluble in excess, 
 but soluble in caustic alkali. 
 
 White precipitate. 
 
 White precipitate. 
 
 No precipitate. 
 
 White precipitate. 
 
 Yellow precipitates. 
 
 Yellow precipitate. 
 
 Black precipitates. 
 
BISMUTH. 
 
 151 
 
 Testing the Value of Lead Salts. — A very simple method of test- 
 ing the value of salts of lead — that is, of ascertaining the quantity of lead 
 in a solution — is to dissolve, say 10 grains of bichromate of potash ( red 
 chrome) in hot water, and put the solution into a tall glass jar; then take a 
 given weight, say 100 grains of the lead salt, whether acetate or nitrate, and 
 dissolve in one measure of the alkalimeter of water ; add this gradually to 
 the chrome solution until the liquor above the precipitate becomes colour- 
 less, or until a drop of the liquor added to a drop of the lead solution on a 
 glass plate is not turned yellow. The number of graduations taken to 
 effect this is noted ; then, as every 148*6 of bichromate of potash is equal 
 to 379*4 acetate of lead, or 330 nitrate of lead, the quantity required by 
 the 10 grains chrome is easily calculated — being for acetate 25*6, and for 
 nitrate 23 grains. All the solution required above these measures will 
 indicate impurities. The average of many experiments gave the following 
 as fair qualities : 
 
 Commercial nitrate required. 24 grains. 
 
 ,, white sugar , 27 , r 
 
 ,, brown sugar , 28 ,, 
 
 The quantity of lead in a solution may be tested in the same way. 
 
 Thallium (204). 
 
 This metal was discovered by Mr. W. Crookes by means of the 
 spectroscope, in giving, a single intense green line. It accompanies certain 
 kinds of iron pyrites, particularly that imported from Spain, which has both 
 copper and lead, which latter metal thallium resembles in appearance. It is 
 very quickly tarnished in the air. Its oxide is soluble in water, and has 
 an alkaline reaction on litmus. Its salts are mostly white. Mr. Crookes 
 has given an exhaustive investigation into the salts of this metal, published 
 from time to time in the Chemical News ... As yet, none of its salts have 
 been used in manufacture. 
 
 Bismuth. (Bi 210). 
 
 This metal occurs in Nature in the metallic state, and also in com- 
 bination with other substances. When found in the metallic state, it is 
 separated from the earths, through which it is diffused by melting: the 
 metal sinking to the bottom of the crucible is separated from the earthy 
 matters which float on the surface. It is a white metal, with a reddish 
 hue, very crystalline in structure, volatilises at a red heat, and burns in 
 the air with a pale blue flame, forming oxide of bismuth. The metal does 
 not tarnish by exposure to the air. It combines with oxygen in several 
 proportions. The protoxide =*= Bi 2 0 3 is formed by combustion, as stated, 
 
152 
 
 TIN. 
 
 and is of a straw-yellow colour. There is also a suboxide = Bi 4 0, and a 
 peroxide = Bi 2 0 5 , but these oxides have no corresponding salts. 
 
 Sulphate of bismuth may be prepared by dissolving the oxide in 
 concentrated sulphuric acid ; chloride of bismuth by dissolving in hydro- 
 chloric acid; these salts, added to water, are decomposed — the chloride 
 forms with water an oxychloride, setting hydrochloric acid free. 
 
 Nitrate of Bismuth. — Nitric acid dissolves bismuth easily, forming 
 the nitrate, which crystallises in beautiful white crystals. This salt is also 
 decomposed by water ; indeed, all the neutral salts of bismuth are decom- 
 posed by water, there being formed salts (oxysalts). 
 
 The action of re-agents upon the solutions of bismuth is as follows : — 
 
 Potash, soda, and ammonia,... White precipitates, not soluble in excess. 
 
 Carbonates of the alkalies, White precipitates, not soluble in excess. 
 
 Fellow prussiate of potash,... .White precipitate. 
 
 Red prussiate of potash, Pale yellow precipitate. 
 
 Solution of galls, Orange-yellow precipitate. 
 
 Iodide of potassium, Brown precipitate. 
 
 Chromates of potash, ....Yellow precipitates. 
 
 Sulphides of the alkalies, Black precipitates. 
 
 Tin (Sn 118). 
 
 This metal has nearly the colour and lustre of silver; it is one of the 
 few metals which were known to man at a very early period of his history, 
 and was extensively used in all countries, both east and west, having any 
 pretensions to civilisation. This was probably owing to the extensive use 
 of bronze by all countries in ancient times, it being an alloy of copper and 
 tin. The ores of tin are easily reduced to the metallic state, being in 
 general oxides; so that by merely fusing them with carbonaceous matter, 
 such as wood or charcoal, which combines with the oxygen, the metal is 
 fused, and sinks in the melted state to the bottom of the furnace. 
 
 The principal localities for obtaining tin are Cornwall, Bohemia? 
 Mexico, and the East Indies ; in this country the metal has been wrought 
 from the earliest ages, and may be said to be the first nucleus of civilisa- 
 tion in this country, as it formed the great mart where the civilised and 
 commercial Phoenicians obtained the tin which was so abundantly used by 
 them. The ore is found in Cornwall both in veins traversing the primary 
 rocks, and in small rounded grains in the neighbourhood of these rocks, 
 imbedded in what geologists term the alluvial deposit , signifying the deposit 
 formed by the washing away of the fragments of the primary rocks with 
 water. This gives the purest tin, and is distinguished by the name of 
 stream tin. The ore obtained from the veins is generally contaminated 
 with other metals, such as iron, copper, arsenic, and the like, but is 
 partially purified by liquation — that is, by heating the mass to the melting 
 
PROTOXIDE OF TIN. 
 
 153 
 
 point of tin, which melts out and leaves the others. Several other opera- 
 tions of refining follow this, which need not be detailed; but there are 
 often small portions of the impurities remaining in a portion of the tin. 
 That portion which contains these impurities is termed block tin. The 
 purer portions of the metal, termed grained tin, is heated till it becomes 
 brittle, and is then let fall from a height, which splits it into small bars or 
 prisms, and in this state it is found in commerce. These bars in bending 
 make a peculiar crackling noise, and become heated — phenomena probably 
 owing to the separating of their parts, and the sudden fracture caused by 
 bending. 
 
 The salts of tin are very extensively used in dyeing and printing both 
 cotton and woollen. Their introduction as mordants may be considered as 
 forming an era in the art of dyeing, and like many other important improve- 
 ments in this art, was the result of accident, an account of which is given by 
 Berthollet as follows : — “ A little while after the cochineal became known 
 in Europe, the scarlet process by means of the solution of tin was dis- 
 covered. It is stated that about the year 1630, Cornelius Drebbel observed, 
 by an accidental mixture, the brilliancy which the solution of tin gave to 
 the infusion of cochineal. He communicated his observation to his son-in- 
 law, Kuffelar, who was a dyer at Leyden. He soon improved the process, 
 kept it a secret in his workshop, and brought into vogue the colour which 
 bore his name.” 
 
 Soon afterwards, a German chemist found out the process of dyeing 
 scarlet by means of the solution of tin. He brought his secret to Lon- 
 don in 1643 ; it became known to others, was soon afterwards diffused 
 over Europe, and its applications became more extended, as whenever a 
 new dye drug was introduced into the art, the solution of tin was univer- 
 sally applied, by which means it became a standard mordant for the various 
 dyewoods, such as logwood, Brazil wood, and the like. There is every 
 probability that this was only a rediscovery, and that salts of tin were used 
 by dyers in ancient tim^s, but its use being kept secret, the knowledge of 
 it died with its possessor. 
 
 Copper boilers used for dyeing woollen and silks used to have a part 
 covered with or made of tin, to prevent the acid mordant from acting upon 
 the copper, and this it does by a galvanic action, the tin being slowly acted 
 upon, while the copper is protected. Now, wood vessels are used, the 
 liquid being heated by steam. 
 
 Tin combines with oxygen in three different proportions — 
 
 Protoxide, SnO. 
 
 Sesquioxide, Sn 2 0 3 . 
 
 Peroxide, Sn0 2 . 
 
 There are salts of tin corresponding to these oxides, all more or less useful 
 in dyeing. 
 
 Protoxide of Tin, or Stannous Oxide, is formed by precipitation from 
 a solution of the protochloride of tin with carbonate of potash or soda. It is 
 
154 
 
 PROTOSULPHATE OF TIN. 
 
 obtained as a white powder, which is a hydrate of the oxide, and which, if' 
 heated to 176°, loses its water of combination and becomes black, and may- 
 be kept in this state ; but jf brought to a red heat, or into contact with a 
 red-hot body, it takes fire, and in burning passes into -the state of peroxide. 
 The white hydrated oxide is easily dissolved in acids, and also in solutions 
 of the alkalies, but these alkaline solutions are not permanent : for if diluted 
 with water, a portion of the tin is precipitated, and another portion passes 
 into the state of peroxide. Also, when brought into contact with other 
 oxides which yield their oxygen freely, such as peroxide of iron, a reaction 
 takes place : the iron is reduced to a lower state of oxidation, and the tin 
 is raised to a higher. These reactions and properties are taken advantage 
 of in some of the operations in dyeing. 
 
 The protoxide of tin and its protosalts all come under the denomi- 
 nation of stannous salts: and it may be remarked of them, as a general 
 characteristic, that they all absorb oxygen from the air by exposure. 
 
 Protochloride of Tin (Salts of Tin, or Tin Salts '). — This salt is pre- 
 pared by dissolving tin in strong hydrochloric acid; with the assistance of 
 heat, the solution is rapidly evaporated, having, some tin in it to prevent 
 oxychlorides being formed, and the crystals collect at bottom. The 
 crystals were formerly said to contain three equivalents of water, about 
 22 per cent.; but according to investigations by the late Dr. Penney,, 
 they contain only two equivalents. The crystals dissolve in a small 
 portion of water; but if put into a large quantity, the whole becomes- 
 milky, and a white powder separates, which is an oxychloride of tin. A 
 complete and clear solution of salts of tin in water cannot be retained, 
 for any length of time on account of the great attraction which this 
 salt has for oxygen. A little hydrochloric acid put into the water, how- 
 ever, has the effect of greatly retarding, and, indeed, of almost wholly 
 preventing this decomposition. In establishments where the dyers pre- 
 pare their own salts of tin , they do not crystallise it, and as there is nearly 
 always an excess of acid, some of these phenomena mentioned may not 
 have been observed. 
 
 On adding potash to salts of protochloride of tin, a double salt is 
 formed of chloride of tin and chloride of potassium, which may be 
 crystallised. 
 
 Tin salts are occasionally adulterated with sulphate of zinc or 
 magnesia. This can be detected by adding to a solution of the salt a 
 little pure hydrochloric acid, then a few drops of a solution of chloride 
 of barium. If any sulphates be present there is a white precipitate pro- 
 duced. Zinc may be present as chloride; in this case the crystals, by 
 standing, become damp, as chloride of zinc attracts water. 
 
 Protosulphate of Tin. — Sulphuric acid dissolves tin slowly, and 
 forms a thin pasty-looking mass, which, by evaporation, yields crystals. 
 This salt is not used in the dye-house ; it is. indeed, immediately decom- 
 posed by aqueous dilution. 
 
DEUTOXIDE. 
 
 155 
 
 Protonitrate of Tin. — Protoxide of tin dissolves easily in dilute 
 nitric acid, but it cannot be concentrated, from its liability to pass into 
 the state of peroxide. When nitric acid of specific gravity 1T14 = 23 of 
 Twaddell, is poured upon the metal, it dissolves it rapidly, and much heat 
 is evolved, which ought to be kept down by placing the vessel containing 
 the acid in cold water. If this be properly done, a protonitrate of tin is 
 formed. But should the heat be allowed to rise too high, the nitric acid 
 is also decomposed, and the tin passes into a higher state of oxidation- 
 
 Tartrate of Potash and Tin is prepared by dissolving protoxide of 
 tin in bitartrate of potash ( tartar or cream of tartar). This forms a 
 soluble salt, occasionally used in dyeing woollens; but the common mode 
 of preparing this mordant is by adding tartar to the salts of tin. 
 
 A combination of the protoxide of tin, arsenic, and soda, and also 
 alumina, tin, and soda, have been used in calico-printing. 
 
 Deutoxide, or Sesquioxide of TiN = Sn 2 0 3 , can be prepared by 
 adding to a saturated solution of protochloride of tin some newly- 
 % precipitated peroxide of iron: a double decomposition takes place as 
 follows : — 
 
 Two proportions proto- j 4 
 
 chloride of tin, J 2 Sn. 
 
 One proportion of per- ) 2 
 oxide of iron...... / 3 O. 
 
 Protochloride of iron 
 in solution. 
 
 Sesquioxide of tin pre- 
 cipitated. 
 
 Strong hydrochloric acid dissolves this oxide, and forms with it a sesqui- 
 chloride, thus: — 
 
 3 O.. ^ 3 Water. 
 
 2 Sn. 
 
 6 H.. ^ 
 
 6 Cl. Sesquichloride of tin. 
 
 One sesquioxide of tin 
 Six hydrochloric acid, | 
 
 The other salts corresponding to this oxide have not been examined ; 
 but the distinctive character of the oxide itself may be made evident by 
 the two following reactions: — Ammonia dissolves this oxide, but does 
 not dissolve the protoxide; and hydrochloric acid dissolves this oxide, 
 but does not dissolve the peroxide. These reactions, however, may not 
 positively prove the existence of such a salt as a sesquisalt ; and, indeed, 
 many chemists do not admit these salts. Mr. Ordway, however, in 
 Silliman’s American Journal , gives strong evidence in favour of such salts, 
 which practical dyers will be inclined to homologate. When nitrate of tin 
 is prepared by dissolving the metal in weak nitric acid, ammonia is formed 
 in the process ; but the spirit mordant made by this means is not regular in 
 its results in dyeing, so that when such spirits are required it is customary to 
 add 1 lb. of sal-ammonia to 9 lbs. of nitric acid at 32° Twad., and dissolv- 
 ing in this 14 lb. of tin, put in in bars. These salts of tin which are supposed 
 to be sesqui are distinguished from protochloride of tin by their colour 
 
156 
 
 PERCHLORIDE OF TIN. 
 
 being dark or brownish; while both proto and perchlorides are colourless 
 or white. Every dyer who is in the practice of preparing his own tin 
 mordants will recognise the distinction, although he may not know the 
 chemical difference; but he knows there are differences in the colours or 
 tints produced. Ammonia in tin salts is generally used for dyeing wool. 
 Different methods for preparing tin salts will be given when treating of 
 the different dyes and their receipts. There can be little doubt but that 
 a more full investigation into the sesquioxide and its salts would explain 
 many of the hitherto unexplained phenomena of the process of dyeing ; 
 and that it is highly probable the formation of salts of this class play a 
 considerable part in many dyeing operations, such as those processes 
 in which chloride of tin is mixed with pernitrate of iron, as for royal 
 blues, &c. 
 
 Peroxide of Tin. — The ores of tin, termed tinstone , are mostly per- 
 oxide. They are black, shading to brown : in this state the oxide is not 
 soluble in acids, but becomes so by previous ignition with an alkali. 
 
 When metallic tin is put into dilute nitric acid, and the action . 
 allowed to proceed rapidly, or when heat is applied, there is formed a 
 hydrated peroxide, as a white mass, which contains 11 proportions of 
 water. Dilute hydrochloric acid dissolves this oxide slightly, but it is 
 not soluble in nitric or sulphuric acids. If acted upon by hydrochloric 
 acid, and allowed to stand for some time, and the supernatant liquor then 
 poured off, the remaining oxide is soluble in water. If this hydrated 
 peroxide be dried with heat, it loses its water, and passes into the same 
 state as the ore. Boiling water poured upon it will effect similar changes 
 
 The peroxide of tin is obtained easily by precipitation from a solution 
 of bichloride, on adding an alkaline carbonate. Thus prepared, and in this 
 condition, the peroxide is easily dissolved in hydrochloric acid, either 
 strong or dilute ; but if this oxide be heated in any way, as by pouring 
 boiling water upon it, strong hydrochloric acid will not dissolve it, and 
 dilute acid only partially. The oxide has now indeed every property that 
 it has when formed by the nitric acid process. It is also soluble in pure 
 water, after being made into a paste with strong hydrochloric acid, but 
 the addition of a little of this acid to the watery solution will precipitate it. 
 
 The changes effected upon this oxide by heat or applying boiling 
 water are supposed to be owing to its state of hydration ; but be that as it 
 may, these peculiarities ought to attract the attention of the practical dyer, 
 as the peculiarities of different tin salts and the annoyances to which they 
 give rise are very considerable, and may only require the exercise of a little 
 care to be avoided. The hydrated peroxide of tin is very soluble in caustic 
 alkalies. 
 
 The peroxide of tin has been termed stannic oxide and stannic acid , as it 
 has certain acid properties. It combines with alkalies, and forms salts. 
 
 Perchloride of Tin — Stannic Chloride ( Permuriate of Tin).— When 
 
PERCHLORIDE OF TIN. 
 
 157 
 
 tin is dissolved in a mixture of hydrochloric and nitric acids, the salt 
 formed is generally the perchloride = SnCl.*, and is the salt most generally 
 used in the dye-house. But from what has been stated in reference to the 
 separate oxides and salts, it will be evident that this subject stands in need 
 of further investigation — the modes of preparing these mordants are so 
 varied in the proportions of each of the acids, in the quantities of tin used, 
 and in the manner of adding the tin ; all and each of these circumstances, 
 it will be observed, make a difference. If tin is added too rapidly, the 
 action may be so violent and the heat so high as to precipitate some of the 
 oxide in an insoluble state, which is termed firing ; and if added too slowly 
 and at a temperature too low, there may be protochlorides formed, or 
 mixtures of the different salts, in very varied proportions ; and hence, no 
 doubt, the cause of the irregularity both in quality and kind of colour pro- 
 duced by tin mordants. Perchloride of tin is sometimes formed by dissolving 
 crystals of the protochloride in a small portion of water, adding a little nitric 
 acid and applying heat, or by passing a stream of chlorine gas through the 
 solution of the salts of tin. These are termed in the dye-house oxychlorides 
 of tin. 
 
 The late Dr. Penney communicated to the Chemical Society a simple 
 means of testing the quantity of tin present in a solution of its salt in the 
 proto-state, founded upon the well-known property of the reduction of 
 chromic acid to oxide of chromium by protoxide of tin. The method 
 recommended for salts of tin is the following 100 grains of the crystals 
 are put into a vessel with 20 oz. of water and half an ounce of hydrochloric 
 acid; 83^ grains bichromate of potash are dissolved in warm water, and 
 placed in an alkalimeter, the whole measuring 100 graduations ; this 
 solution is added by degrees to the solution of tin, which takes on a rich 
 green colour ; the solution of chrome is added, until a drop taken out and 
 put upon a drop of acetate of lead, on a glass or paper surface, gives 
 yellow. If the tin solution is more dilute and put into a large glass jar, the 
 green tint, whenever the chrome is in excess, is perceptibly yellow. A little 
 experience renders the operation simple. The quantity of bichromate (83^- 
 grains) is equal to 100 grains of pure metallic tin ; hence every graduation 
 of the chromic solution taken to effect the change described is equal to one 
 grain of tin. As 83^- grains of bichromate of potash may not be soluble in 
 one measure of the common alkalimeter, two measures may be taken ; in 
 that case two graduations will indicate one grain of tin in the salt tested. 
 
 Solutions of tin, such as are sold to calico-printers under the term 
 single and double muriates , being simply strong and weak chloride, may be 
 tested by taking a measured quantity of the solution and treating it in the 
 same manner. Or by taking a weighed quantity of the solution of tin, say 
 500 grains, and making up with water to fill the alkalimeter, then dissolve 
 41*6 grains of bichromate of potash in warm water, and add the solution of 
 tin to this very cautiously, as long as the tint remains of an olive-green 
 colour, or a drop taken out and added to a drop of lead in solution 
 gives a yellow colour. Whenever the yellow ceases to be obtained, the 
 
158 
 
 RED SPIRITS. 
 
 operation is complete. Finally, by dividing 1000 by the number of gradua- 
 tions taken of the tin solution, the percentage of the tin is ascertained. 
 Thus, say that 41*6 of bichromate of potash required 38 graduations of the 
 tin solution to reduce the chromic acid, then 
 
 38)1000(26-3 — percentage of tin in solution. 
 
 This test only applies to tin in solution in the proto-state, but gives no 
 change in the persalts of tin. 
 
 Spirits. — The solutions of tin, in the technical language of the dye- 
 house, are termed spirits , with prefix to denote their special application, 
 such as red spirits, yellow spirits, plumb spirits, &c. The preparation 
 of these spirits is a matter of much importance and pride amongst dyers, 
 and each has some little peculiarity which he keeps to himself, and on 
 the virtue of which he supposes all his success depends. These pecu- 
 liarities are generally in the proportion of the acids and the tin, and the 
 manner of mixing them; hence the reason that we find one dyer best at 
 reds, another at purples, another at blacks, and another at browns. 
 
 W e will here give a few practical methods for preparing these spirits, 
 as performed in the dye-house, reserving our remarks upon their varieties 
 and effects for our general observations on mordants, to which we intend 
 to devote a separate chapter, in order that we may be able to go fully into 
 the subject. 
 
 The first process in preparing spirits is to feather or granulate the 
 tin. This is done by melting it in an iron ladle, and pouring it, when in a 
 melted state, into a vessel filled with cold water, the hand to be held as 
 high as possible, so that it may pour more in drops. The appearance of 
 the tin in this state is very beautiful. By this process of feathering, a very 
 extended surface of metal is exposed to the acid, which facilitates its 
 solution very much. 
 
 Bed Spirits. — If red spirits be wanted— that is, a mordant for dyeing 
 red upon cotton with Brazil-wood — the general method is to take three 
 measures of muriatic acid and one of nitric acid, then add the tin by 
 degrees to this mixture so long as the aeids continue to dissolve the metal ; 
 care ought to be taken not to add it too rapidly, but bit by bit, adding one 
 piece just as the other is dissolved. We know that this is not generally 
 attended to, as one handful of the metal is put in after another, at certain 
 and too often irregular intervals of time, giving very annoying results. 
 When the metal is put in too rapidly, or too much at once, the action 
 becomes violent, the solution gets heated, the nitric acid is decomposed, 
 ammonia is formed in the solution, and when the solution cools a quantity 
 of peroxidised tin falls to the bottom as a gelatinous precipitate, creating 
 much loss. When spirits thus prepared are used for a brilliant red upon 
 cotton by Brazil-wood, the proper hue is never obtained,' the colour being 
 always more or less brownish. The proportions of the acids for pre- 
 
OXALATE OF TIN. I59 
 
 paring the red spirits are not invariably three to one, the mixture varies 
 from half-and-half to five to one, depending upon the taste and experience 
 of the dyer. Some dyers only dissolve a given quantity of the metal to the 
 pound weight of the mixed acids, varying from one and a half to three 
 ounces to the pound; but according to our experience, the acids, in what- 
 ever proportions they are mixed, ought to be saturated, at least so far as 
 they will become saturated, observing the precautions described above. 
 We have also found that when much nitric acid is used the reds are gener- 
 ally deeper in colour, and have a very great tendency to turn brown, 
 especially if the goods be dried at a high temperature ; but when the 
 muriatic acid prevails, the colour obtained has more of the crimson or rose 
 tint, and is not so liable to become brown or rusty in drying. 
 
 Plumb Spirits. — This solution is prepared by dissolving tin in hydro- 
 chloric acid diluted with about a seventh of water, adding two ounces of 
 tin to every pound weight of acid. The tin, as in other cases, ought to be 
 added gradually. Some, however, add nitric acid, and prefer it thus mixed, 
 and others add as much tin as the acid will dissolve cold. 
 
 Barwood Spirits. — The method given for the preparation of this solu- 
 tion is six measures muriatic and one of nitric acid, adding tin gradually 
 until white bubbles begin to rise to the surface, allowing the solution to 
 stand at least twelve hours before using it — a rather uncertain test of 
 quantity of tin, and of the quality of the spirits. 
 
 Yellow Spirits.— This solution is now seldom used ; it was applied as 
 a mordant for the dyeing of yellow by quercitron bark, and was merely the 
 substitution of sulphuric acid for the nitric acid of the common red spirits. 
 It was proposed by Dr. Bancroft as a question of cheapness in the prepara- 
 tion of scarlet spirits, and was afterwards much used, as stated, for dyeing 
 yellows, as its name implies. By this method of preparation the tin was 
 generally in the proto-state, which gave it a peculiarity in relation to the 
 common red spirits, as it afforded bluer tints with red woods when used as 
 a raising or alterant The tin spirits, called double and single muriates, the 
 salts of tin dissolved in water and muriatic acid, and metallic tin dissolved 
 m hydrochloric acid {plumb spirits ), have all the same effect. Some dyers, 
 however, use the red spirits both as alterants and for dyeing yellows. 
 
 Instead of using hydrochloric acid for preparing spirits, some woollen 
 dyers use sal-ammoniac or common salt, adding it to nitric acid in the pro- 
 portion of 6 lbs. nitric acid to 1 of water, in which 1 lb. sal-ammoniac is 
 dissolved, and then adding 10 oz. of tin. 
 
 Acetate of Tin is prepared by adding a solution of acetate of soda to 
 protochloride of tin ; common salt is formed and acetate of tin ; the former 
 is not hurtful to the dyer. 
 
 Oxalate of Tin may be formed in the same way, by using oxalate of 
 soda, or by dissolving precipitated protoxide of tin in oxalic acid. 
 
160 
 
 STANNATE OF SODA. 
 
 In dissolving tin in hydrochloric acid, it is often observed that towards 
 the end of the process, when a quantity of tin is in the solution, a part of 
 the metal nearest the surface dissolves, while other parts become coated 
 with a crystalline substance soluble only with much difficulty, and occa- 
 sioning both annoyance and loss. This is caused by the bottom por- 
 tion of the solution becoming denser than the upper portions, a galvanic 
 action being induced between those parts of the tin in the weaker portion 
 of the solution and the parts in the stronger, consequently depositing the 
 tin upon the metal in the strongest parts of the solution. This evil can be 
 prevented by occasionally stirring the solution. 
 
 The following is the reaction of solutions of other substances on the 
 protosalts of tin : — 
 
 Potash and soda, 
 
 Ammonia, 
 
 Carbonates of the alkalies, 
 
 Yellow prussiate of potash, 
 
 Red prussiate of potash, . 
 
 Galls in solution, 
 
 Chloride of gold, 
 
 Sulphides of the alkalies, . 
 
 With the persalts of tin — 
 
 Potash and soda, 
 
 Ammonia, 
 
 Carbonates of the alkalies, 
 
 Yellow prussiate of potash, 
 
 Red prussiate of potash, . 
 
 Solution of galls, 
 
 Sulphides of the alkalies, . 
 
 White precipitates, soluble in excess. 
 
 ,, insoluble in excess. 
 
 „ soluble in caustic alkali. 
 
 White precipitate. 
 
 Slight yellow precipitate. 
 
 Deep purple precipitate (purple of cassius). 
 Brown precipitates. 
 
 White precipitates, soluble in excess. 
 
 ,, soluble in caustic alkali. 
 
 No precipitate. 
 
 n 
 
 Yellow precipitates, soluble in caustic potash. 
 
 Stannate of Soda. 
 
 We have already stated that peroxide of tin plays the part of an acid, 
 and is in consequence termed stannic acid ; it combines with alkalies and 
 forms salts termed stannates. The stannate of soda is a most important 
 salt, and is extensively used as a mordant. In some dye-houses it is made 
 as required by adding caustic soda to a saturated solution of perchloride of 
 tin until the precipitate formed is redissolved, which is facilitated by heat- 
 ing the solution. In this way it will be observed that there is also 
 formed a good quantity of common salt, which, however, is not deleterious 
 to its use as a mordant. The manufacture of stannate of soda for dyers 
 and calico-printers has been the subject of several patents. The following 
 are the two principal, a description of which will enable the dyer to under- 
 stand the principle of the formation of the salt. Messrs. Greenwood & 
 
STANNATE OF SODA. 
 
 161 
 
 Mercer prepared the stannate by putting 22 lbs. of caustic soda into an iron 
 pot or crucible placed in a furnace, and bringing to fusion, and when all 
 vapours had ceased being given off, there were added 8 lbs. of nitrate of soda 
 and 4 lbs. of common salt, and when the whole was again on the point of 
 fusion, 10 lbs. of feathered tin were put into the mixture. In this operation 
 the nitrate oxidises the tin, which, combihing with the soda, forms stannate. 
 When the mass cools it is dissolved in water and any impurities allowed to 
 settle ; the clear solution is decanted and evaporated to dryness, and sold in 
 this state. Mr. James Young shortly after improved upon this process. 
 Instead of using metallic tin and nitrate of soda, he took caustic soda, 
 and bringing it to a heat of 600° Fah. in an iron vessel, he added thereto 
 tin ore in powder, which is a peroxide, then recommended the addition 
 of a little nitrate of soda and common salt, which aids ithe flow of the 
 fused mass. After cooling, the mass was dissolved in water, and treated 
 as the other. There have been several modifications of these processes, 
 the result of experience, but they have not been superseded. Stannate 
 of soda, as found in the market, often contains a considerable portion of 
 silica and excess of alkali, and a good quantity of common salt, sometimes 
 as much as 25 per cent. There are some dyers who content them- 
 selves with testing the value of their stannate by dissolving a weighed 
 quantity, and taking the strength by the hydrometer. Nothing could be 
 more fallacious and misleading, because all the . soluble impurities raise 
 the specific gravity ; indeed, the required gravity can easily be obtained 
 without the presence of tin, which is the mordant. The proper object is to 
 ascertain the quantity of tin present in a given weight, which can be done 
 by a very simple process. Weigh 100 grains and dissolve in water, add 
 muriatic acid in slight excess, and put into this a piece of clean sheet zinc, 
 which precipitates the tin in a metallic state, when it can then be collected, 
 washed, and weighed; or this precipitated metal may be dissolved in 
 muriatic acid, and tested as we have described, for protochloride of tin. 
 There are several other simple methods, provided the dyer has a pair of 
 good balances. 
 
 Under this heading we may mention a case that may prove useful as 
 well as illustrative of the care required where tin or its oxides may be present. 
 A large bleaching establishment was annoyed by having goods returned to 
 them after being away for several months, because of large brown stains 
 which shewed themselves when the goods were taken out the folds. Some 
 blamed iron oxide, others mildew and adulterated starch, &c. ; much time 
 and expense were expended to get at the cause, but still goods were re- 
 turned. We had some of the stained goods sent us, and found the stains 
 to be caused by the presence of tin. The starching bowls or rollers were 
 made of bronze ; and during the night, and particularly from Saturday till 
 Monday, moisture condensed upon these rollers, and collected at the lower 
 portion, causing a partial oxidation of the tin in the bronze. When this 
 took place, the first piece that passed through in the morning was stained 
 with tin oxide, which being colourless, the stain was not seen ; but after 
 
 L 
 
162 
 
 CHROMIUM. 
 
 exposure for months in a warehouse where gas was used, a sulphide of tin 
 was formed from the sulphur in the gas producing a brown stain. Care 
 was afterwards taken to clean the rollers every morning before using. 
 Although the workmen never could see the use of doing so, as no dirt 
 was seen, still twenty years have passed since, and no more stains of this 
 sort have occurred. 
 
 Titanium (Ti 50). 
 
 This metal was discovered in 1791. It is generally found in Nature in 
 combination with iron ; a great number of the iron ores of this country 
 seem to contain traces of this metal. It regularly makes its appearance in 
 the blast furnace ; but its proportion in the ores is so minute, that no 
 chemist has yet detected it in analysing them ; and it has not been found 
 in any great quantity. It is not dissolved in any acid except aqua regia , a 
 mixture of nitric and hydrochloric acids. It combines in two proportions 
 with oxygen, forming 
 
 Protoxide, = TiO. 
 
 Peroxide, = Ti0 2 . 
 
 The latter oxide, on account of its combining with the alkalies, and forming 
 soluble salts with them, has been termed titanic acid. 
 
 The salts formed by the action of acids upon this metal have not been 
 much studied ; those which have been investigated most carefully are the 
 salts formed by the peroxide or titanic acid. Solutions of these salts give 
 a brown precipitate with galls ; but all the compounds of this metal are 
 very untractable, and being besides very scarce, they are of little use in 
 the arts. 
 
 Chromium (Cr 52). 
 
 This metal is found in considerable quantities in Nature, combined 
 with lead and iron. The latter (chrome iron) is its principal ore. It is 
 found in America and in different parts of the continent of Europe ; also 
 in Shetland, and in Fife and Perthshires, in Scotland. The composition of 
 the ore is FeO -J- Cr 2 0 3 . 
 
 The metal was discovered in 1797 by Vauquelin. It approaches to 
 cast iron in appearance, but has only been obtained in the state of powder. 
 It is very difficult to fuse, and does not undergo oxidation by exposure to 
 the air. The metal is not acted upon directly by the common acids ; but 
 may be obtained in combination with acids, by decomposing some of its 
 salts or oxides, of which the two following are the most useful, namely, — 
 
 Peroxide or chromic oxide, Cr 2 O s . 
 
 Chromic anhydride, CrO s . 
 
SULPHATE OF CHROMIUM. 
 
 163 
 
 The latter with water forms chromic acid, the acid of the salts named 
 chromates. The oxide of chromium exists combined with iron in the 
 ore, as stated above ; it is not, however, obtained from the ore direct, but 
 by acting upon some of the salts of chromic acid. It is of a beautiful green 
 colour, and may be prepared by various methods ; the following is one 
 method : — 
 
 1 part bichromate of potash. 
 
 1L part sal-ammoniac. 
 
 1 part carbonate of potash. 
 
 Ignite this mixture in a crucible : the chromic acid is decomposed, and 
 the oxide formed. By digesting what remains in water, the oxide is 
 obtained as an insoluble powder. Another and more easily-practised 
 method for the dye-house is that adopted on the continent. Take 9 lbs- 
 of bichromate of potash, and dissolve in 5 gallons of boiling water; then, 
 into a boiler containing 23 gallons of boiling water, put 10 lbs. of the 
 white oxide of arsenic; boil for ten minutes, and allow the liquor to 
 settle. The clear is then mixed with the solution of bichromate of 
 potash, stirring all the time, when very soon the hydrated oxide of chrome 
 is formed and precipitated. After the whole is cool, it is put upon a 
 filter, and the oxide which remains upon the filter is washed with boiling 
 water. If a little hydrochloric acid be added, the chrome oxide is obtained 
 as a green solution. This o^dde has long been used to give a green colour 
 to glass and porcelain, and has lately been introduced and is now used 
 in calico-printing. It is also partially used in the dye-honse for 
 dyeing colours of various tints, all of which have the valuable property 
 of permanency. 
 
 Chloride of Chromium. — The oxide of chromium, as just stated, 
 dissolves readily in hydrochloric acid, and forms a chloride which has a 
 deep green colour and a strong acid reaction. Evaporated nearly to 
 dryness, there are produced red-coloured scales, which give a green 
 solution with water. The following method for the preparation of the 
 chloride has been recommended: Hydrochloric acid is diluted with water 
 until the acid no longer gives off fumes ; it is then heated, and when hot 
 as much of the oxide of chromium, prepared by the arsenic solution, is 
 added as the acid will dissolve ; the whole is then left to settle, and the 
 clear is taken off. This contains some free acid, which would act upon the 
 cotton fibre ; to remove it and obtain the salt in a neutral state, potash or 
 soda ley is poured in gradually, until the oxide of chromium begins to be 
 precipitated. The solution thus prepared has a dark-green colour, and is 
 used for several operations in dyeing. Preparations of this salt, or rather 
 mixture of salts, have been long used in calico-printing. These are made 
 by mixing together chromate of potash, hydrochloric acid, and tartaric 
 acid, in a great variety of proportions, giving green tints of various depths 
 according to the mixture used. 
 
 Sulphate of Chromium. — Sulphuric acid added to oxide of chromium 
 
164 
 
 CHROMIC ACID. 
 
 dissolves it, and forms a green-coloured solution, which does not crystallise. 
 If evaporated to dryness, it loses its solubility in water. By adding 
 sulphate of potash or a solution of potash to solution of chromium, 
 taking care not to precipitate any of the oxide, there is formed a double 
 salt, termed chrome alum . The solution of this double salt is a bluish 
 purple ; it crystallises easily, giving dark purple-coloured crystals ; but 
 care must be taken that the solution is not heated to the boiling point, 
 as it is thereby turned green, and yields no crystals. 
 
 Oxalate, acetate, tartrate, &c., of chromium may be obtained by 
 dissolving the oxide in any of these acids ; they all give green-coloured 
 solutions. If we mix "together one part of bichromate of -potash, two of 
 crystallised oxalic acid, and two of binoxalate of potash, and dissolve the 
 mixture in boiling water, a salt is formed which crystallises in nearly black- 
 coloured crystals. It is a double oxalate of chromium and potash. 
 
 Chromic Acid. — Salts of this acid are prepared directly from the chrome 
 iron ore ; and the acid is obtained by decomposing these salts. Chromic 
 acid is of a beautiful deep orange colour, approaching to scarlet, and may 
 be obtained in a crystalline form, having the following formula, Cr0 4 H 2 . 
 Various methods have been proposed for preparing it; the following, by 
 the late Mr. Robert Warrington, is probably the most simple: — “Take 
 100 measures of a cold saturated solution of bichromate of potash (pre- 
 pared by boiling, and then allowing the solution to cool and deposit the 
 excess of the salt), and add to this from 120 to 150 measures of con- 
 centrated sulphuric acid; the latter should be free from sulphate of lead, 
 as otherwise it would fall as chromate and sulphate of lead with the 
 chromic acid on dilution with the bichromate. The mixture is then 
 allowed to cool, and the chromic acid gradually crystallises in beautiful 
 dark crimson needles. Decant the fluid part, and place the crystals with 
 the adhering sulphuric acid -on a thick flat tile of biscuit porcelain; 
 another tile is then to be placed upon the crystals, and the whole 
 submitted to a pressure for a considerable time. On removing the 
 chromic acid, it will be found In a perfectly dry state, and yielding a mere 
 trace of sulphuric acid on examination.” 
 
 Chromic acid may also be prepared from the chromate of lead, which 
 results from the mixture of a salt of lead and bichromate of potash at the 
 bottom of the chrome tubs used in dyeing yellows. Two parts of strong 
 sulphuric acid being added to one part of dry chromate of lead slightly 
 heated, and allowed to stand for about twelve hours ; water is then added, 
 which causes the lead to be precipitated as a sulphate, and the chromic 
 acid, mixed with a little sulphuric acid, remains in solution. The liquid 
 is decanted and evaporated at a boiling heat; on cooling, the greater 
 portion of the chromic acid separates in beautiful carmine-red crystals. If 
 the process be carefully conducted, a great portion of what is now little 
 better than thrown away might be made useful by a trifling addition of 
 
BICHROMATE OF POTASH. 
 
 165 
 
 expense; Another method of preventing waste is to add potash to the 
 solution, so as to form chromate and sulphate of potash, which may after- 
 wards be separated by crystallisation. 
 
 Chromic acid combines with the different bases, and forms a series of 
 important salts. With potash it combines in two proportions, forming 
 what is termed the yellow and the red chromate of potash. The yellow 
 chromate of potash may be prepared by adding to two pounds of red 
 chromate one pound of caustic potash ; it crystallises in small crystals of 
 a rich deep lemon colour, composed of one proportion of acid and two of 
 potassium, K 2 Cr0 4 . This salt is not much used in the arts. 
 
 Bichromate (Red Chromate) of Potash. — This salt may be prepared 
 from the yellow chromate by adding a little sulphuric- acid, which combines 
 with a portion of the potash, leaving two proportions of chromic acid 
 in union with one proportion of potassium, represented as KHCr0 4 ; it 
 crystallises in large square tabular crystals of a rich orange-red colour. 
 This is the salt used in the arts, not only for dyeing, but for the pre- 
 paration of other chrome compounds; it is prepared on the large scale 
 in the following manner: — Chrome iron ore, after being finely ground 
 and sifted, is mixed with a quantity of dried nitrate and carbonate of 
 potash. This mixture is thrown into a reverberating furnace, and sub- 
 jected to a powerful heat, being occasionally stirred. When perfectly 
 calcined, the- mass is raked out and dissolved in water. It is then boiled 
 for several hours, after which the insoluble portion is allowed to settle, 
 and the solution decanted; this is evaporated, and leaves the yellow 
 chromate of potash crystallised. The chemical changes which take place 
 in the furnace are these: the nitre gives off oxygen, which combines 
 with the oxide of chromium, and forms chromic acid ; this unites with 
 the potash of the nitrate and of the carbonate, and forms the yellow salt 
 or chromate which is soluble in water, and. is afterwards separated as 
 described. It contains also soluble impurities, such as caustic potash, 
 silicate and aluminate of potash, which are separated by the succeeding 
 operations of boiling and crystallisation. 
 
 The bichromate, which is the salt used in dyeing, is prepared from the 
 yellow salt obtained as above, as follows : — Into a concentrated solution is 
 poured acetic or sulphuric acid. The latter acid, though often used, is 
 not well adapted for the purpose, as the sulphate of potash formed is 
 very difficult to separate from the bichromate, and constitutes a serious 
 adulteration. Acetic acid is preferable, and is now generally employed. 
 The quantity of the acid is so regulated, that it combines with the one- 
 half of the potash in the yellow salt, leaving two proportions of chromic 
 acid in union with the other half. The solution of yellow chromate being 
 concentrated before the addition of the acetic acid, the bichromate formed 
 has not as much water as will hold it in solution, and is therefore thrown 
 down as an orange-coloured powder ; this is carefully collected, dissolved 
 in water, and crystallised by slow evaporation. 
 
166 
 
 CHROME YELLOW. 
 
 Another method is by heating finely-ground ore with chalk and 
 carbonate of potash to redness in a current of air; the mixture absorbs 
 oxygen and becomes yellow ; it is treated with water, and carbonate of 
 potash added to precipitate the lime ; the yellow solution is drawn off, and 
 nitric acid added, and on evaporating the solution crystals of bichromate 
 of potash are formed. 
 
 When the bichromate of potash has been prepared by sulphuric acid, 
 as in the first process, it is very liable to contain sulphate of potash, and 
 that often to a great extent. This salt may be detected by dissolving a 
 small quantity of the chromate in distilled water, adding to it a little pure 
 nitric acid, and then nitrate of barytes, which will give a white precipitate 
 if a sulphate be present. The solution used in testing should be much 
 diluted. If any chloride of potassium be present, it may be detected by 
 adding a little nitrate of silver to a solution of the chromate, similarly 
 prepared by having a little nitric acid added to it; in this case a white 
 precipitate results. 
 
 Soda has been tried in the preparation of this salt to form a bichromate 
 of soda, which might be equally useful to the dyer, but this base is not 
 used for the reasons already assigned at page 109. 
 
 Chromate of Lead. — The chromates of other bases or metals are 
 obtained by adding solutions of their salts to solutions of either the 
 yellow or red chromate of potash. For example, when a salt of lead — e. g. 
 the acetate or nitrate, is added to a solution of bichromate of potash, the 
 chromate of lead is formed and precipitates as a yellow powder, con- 
 stituting the chrome yellow dye. If this yellow precipitate is digested in 
 hot caustic ley, a basic salt of lead and chromium is formed, having two 
 proportions of lead and one of chromic acid : it is therefore a subchromate 
 of lead. This is a deep orange precipitate, approaching to a scarlet, and 
 constitutes the orange dye. If a little chromate of lead (the grounds of the 
 chrome tub) be dried, and added to some fused nitre in a crucible as long 
 as effervescence and red fumes are observed, and the melted mass is then 
 poured out, there will be at the bottom some subchromate of lead, which 
 may be washed out by water : it is of a rich vermillion red, far superior in 
 tint to anything we have ever seen as a dye — to produce which on the fibre 
 is worth aiming at. 
 
 Chrome Yellow. — The chromate of lead has almost completely 
 superseded the use of vegetable dye-stuffs in dyeing yellow, orange, 
 and green upon cotton fabrics. To dye a yellow, the goods are immersed 
 or wrought through a solution of either acetate or nitrate of lead, from 
 which, after being tightly wrung or pressed, they are passed through a 
 solution of bichromate of potash, and the chromate of lead is thus formed 
 upon and within the fibre. The goods are put several times through this 
 operation when deep shades are required; or, what is now more generally 
 practised, the lead solution is added to lime water as long as the precipitate 
 
CHROME YELLOW. 
 
 16 ? 
 
 formed is re-dissolved, and the goods are wrought through this solution, and 
 then passed through the bichromate solution; or the lead solution may be 
 added to potash or soda. Yellows dyed by alkaline solutions of lead are not 
 so liable to redden. Other qualities of yellow are also obtained by adding 
 hydrochloric acid to the solution of bichromate of potash, distinguished 
 as acid yellow. When dyeing yellows with the acid salt of lead, on passing 
 the goods into the chrome solution, there is a great quantity of chromate of 
 lead formed which is not in the fibre : this precipitates to the bottom, and 
 causes considerable loss. We have already shewn that this chromate of 
 lead may be used for making chromic acid ; it is very soluble in alkalies, 
 and may be made useful in that way also in the dye-house. When this 
 method is practised for dyeing a quantity of goods in different parcels 
 to be dyed of the same shade of colour, there is a liability to inequality, 
 as the chromate solution is not renewed each time, only an addition of the 
 chrome salt is made for each parcel of goods passing through the dye ; 
 there therefore follows an accumulation of free acid in the solution which 
 re-acts upon the colour, varying the tint of different lots. So well are 
 these circumstances known in practice, that if yellow of a red tint is 
 required, or what is termed amber , nitrate of lead is used in preference to 
 the acetate in proportion to the depth of redness required. This gives free 
 nitric acid in the dye, which acts more powerfully than the acetic acid upon 
 the chromate of lead. The same effects are produced by adding a little 
 nitric acid to the chrome solution. The action of the nitrate of lead added 
 to bichromate of potash may be thus stated: Suppose that 100 lbs. of 
 cotton goods are to be dyed yellow, and that the dyer use 330 ounces 
 nitrate of lead, which, if all were taken up by the cotton, there would be 
 required 204 ounces of bichromate of potash, thus : — - 
 
 330 oz. nitrate of l 206 lead 
 
 lead, composed 63 N0 3 
 
 of ( 63N0 3 
 
 204 oz. of bichro- ( 164 
 
 mate of potash... 1 1 hydrogen 
 
 { 1 potassium .... 
 
 All the lead used is not imbibed by the cotton, therefore much less 
 bichromate is required than that given here ; but the action is the same in 
 relation to the lead really fixed upon the goods. The same reaction 
 takes place when acetate of lead is used, but the free acetic acid does 
 not act so powerfully upon the chromate of lead forming the dye. 
 When subsalts of lead are used no acid is liberated — hence the decided 
 preference given to these salts in dyeing. For instance, were we dye- 
 ing 100 lbs. of cotton in different parcels — say 10 lbs. at a time — one 
 after the other, without a new liquor for each, only adding a little lead 
 for each, the last parcel would have the same chance as the first of 
 being uniform in the tint. These remarks also enable us to appreciate 
 the use of alkaline solutions of lead. 
 
 Chromate of lead. 
 
 Nitric acid. 
 Nitrate of potash- 
 
168 
 
 CHROME ORANGE. 
 
 Chrome Greens are dyed in tlie same manner as the yellow, the 
 goods being previously dyed blue by means of the blue vat. In dyeing 
 green, the acid salts of lead are not used, as the free acid tends to redden 
 the hue ; the goods are not allowed to stand for any time out of the solu- 
 tion of the bichromate-, as that also reddens the yellow. If acid salts 
 are used, even with the greatest amount of care, there is much difficulty in 
 avoiding brown blotches and light parts; but there are fewer of these 
 difficulties experienced when the lead is either in a subacetate state, or in 
 the state of an alkaline salt. 
 
 Chrome Orange is obtained by fixing upon the goods the subchromate 
 of lead, as already mentioned. This is effected by dyeing the goods a deep 
 yellow, and passing them through a strong hot alkaline solution, which 
 combines with a portion of the chromic acid, and leaves the subchromate 
 of lead upon the cloth. The alkaline solution commonly used for con- 
 verting the chromate of lead into the subchromate upon yarn or cloth is 
 lime, for piece goods soda is used. 
 
 The following receipt will produce a good orange upon a hundred 
 pounds weight of cotton : — 
 
 Thirty pounds of brown sugar of lead and 17 lbs. of litharge are 
 put into a boiler with about 12 gallons of water, and boiled together for 
 an hour or so, until the litharge is dissolved; then a quantity of lime> 
 from one to two pounds, is added, any sediment formed is allowed to 
 settle, and the clear fluid drawn off and put into a tub ; 12 lbs. bichromate 
 of potash are dissolved in another tub ; these are stock tubs, from 
 which the dyeing tubs are supplied. Two other tubs, capable of 
 allowing ten pounds of yarn to be wrought in them with freedom, are 
 filled, one with water, to which a little of the lead solution is added, and 
 the other with lime water; 10 lbs. of the yarn (a bundle) is now wrought 
 for some time through the tub containing the lead, wrung out, and put 
 through the lime water ; a little more lead is added, another bundle is 
 passed through the same tub, renewing the lime-water each time. The 
 whole are passed two or three times through this operation, according 
 to the depth of orange wanted. The bundles are next wrought through 
 a tub of water, to which is added some of the solution of the bichromate 
 of potash, then passed through the lead solution, and again through the 
 chrome. A saturated solution of newly slaked lime is brought to the 
 boiling point; in this the yarn is wrought, either by drawing some off 
 in tubs, or by the most convenient method that circumstances will allow, 
 until the colour is changed to a deep orange or scarlet. It is then taken 
 out, passed through another tub filled with boiling water, to which is 
 added a small quantity of solution of soap, soda, and oil; afterwards 
 it is wrung out and dried at a high temperature. The raising of the 
 orange, as the hot liming is termed, is the most trying operation. If the 
 lead has not been properly prepared, or if there be any mismanagement 
 in the operation of fixing it upon the fibre, the hot lime will take all the 
 
TESTS FOR CHROME. 
 
 169 
 
 colour off, leaving but a red salmon shade. Or if the goods are unequally- 
 dyed, the colour will come off in parts ; and, what is still more frequently 
 the case, the chromate of lead being entirely soluble in lime-water at a 
 temperature a little under boiling, if the lime solution is allowed to 
 become too cold, the colour will be discharged. The lime-water ought 
 to be at the spring of the boil , and as we have seen (page 116), the higher 
 the temperature the less lime is held in solution, consequently the less 
 risk of failure. Great care is necessary, for an orange once wrong, 
 it is very difficult to recover. 
 
 Bichromate of potash has been very extensively used of late as a 
 mordant for a variety of colours upon woollen, and is entirely superseding 
 several of the old processes for dyeing many of the ordinary shades, 
 which were very tedious in manipulation. It is also extensively used 
 for dyeing catechu browns upon cotton, examples of which will be given 
 in the receipt. We may mention that working much with solutions of 
 chrome and lead is very injurious to the hands, especially if there be any 
 part of the skin broken, producing often very severe sores ; a solution of 
 gutta-percha applied over the sore, forming an artificial skin, has the effect 
 of preventing this annoyance. 
 
 Tests for Bichromate of Potash. — Tests for the strength and 
 quality of bichromate of potash may easily be formed, thus: — Take pure 
 nitrate of lead, say 165 grains, and dissolve in 200 measures of water; this 
 ought to precipitate 74 grains of bichromate; so that it is merely required 
 to dissolve 74 grains of bichromate of potash, and adding the nitrate 
 of lead solution as long as any precipitate takes place; if all the lead 
 is requisite, the chrome is good, but every three graduations of the 
 lead solution left, after precipitating all the chrome, will represent about 
 one per cent, impurity of the bichromate; or the same method may be 
 taken as described for lead (page 151). These operations are easy, and 
 may be performed by any practical dyer, although little acquainted with 
 chemical manipulations. 
 
 The following is the reaction of salts of oxide of chromium with 
 other substances in solution : — 
 
 Potash and soda, Greenish precipitates, soluble in 
 
 excess. 
 
 Ammonia, Blue precipitate. 
 
 Carbonates of the alkalies, Light-green precipitates. 
 
 Yellow and red prussiates of potash,... No precipitates. 
 
 Solution of galls, Greenish precipitate. 
 
 The reaction of bichromate upon the re-agents is as follows: — 
 
 Solutions of lead, Yellow precipitates, soluble in potash 
 
 Silver salts, Red brown. 
 
 Zinc, Forms with these salts a double salt, 
 
 which is brown, and crystallises. 
 
170 
 
 tungstenum. 
 
 Vanadium (V 51-3). 
 
 This metal was discovered in 1830. It is found in Nature combined 
 with lead and iron, but is exceedingly rare. Small samples of its oxide, 
 termed vanadic acid, are sold by the grain as a chemical curiosity. It 
 has a strong resemblance to chromium in many of its chemical characters, 
 and combines with oxygen in three proportions : — 
 
 Suboxide =V 2 0. 
 
 Protoxide = VO . 
 
 Vanadic acid = V 2 O 3 . 
 
 There is no combination of vanadium with an acid corresponding to 
 the suboxide, but there are salts corresponding with the protoxide ; these, 
 in solution, produce with 
 
 Ammonia, Brown precipitate. 
 
 Yellow prussiate of potash, Yellow precipitate. 
 
 Red prussiate of potash, Green precipitate. 
 
 Galls, Blue-black precipitate. 
 
 Sulphides of the alkalies, Brown-black precipitate. 
 
 Vanadic acid combines with the alkalies, and forms a variety of 
 coloured salts, nearly all soluble in water. All the reactions of the 
 compounds of this metal give strong hopes that, were it found plentifully, 
 it would become a useful substance in the hand of the dyer; although 
 in the meantime, from its price and scarcity, it is of no importance to him. 
 
 Tungstenum or Wolfram (W 181). 
 
 This metal has the appearance of iron, and exists in Nature chiefly in 
 combination with lime. It combines with oxygen in two proportions : — 
 
 Binoxide of tungsten = WC> 2 . 
 
 Tungstic acid =W0 3 . 
 
 Binoxide of tungsten is a brown-red powder, which does not dissolve 
 in acids, and there are therefore no salts of tungstenum corresponding 
 to this oxide. The oxide passes readily into the state of tungstic acid 
 by combining with more oxygen ; and it is in this state that it is found 
 in Nature forming a tungstate of lime. By dissolving this mineral in 
 hydrochloric acid, the lime is dissolved, and the tungstic acid remains 
 as a yellowish powder, which combines with alkalies, and forms soluble 
 salts. Acids added to these salts give yellow precipitates. 
 
 If tungstic acid is dissolved in sulphide of potassium, or of sodium, 
 and an acid is added, the tungstenum is precipitated in the state of 
 sulphide, of a deep-brown colour, nearly black. 
 
MOLYBDIC ACID. 
 
 171 
 
 Molybdenum (Mo 96). 
 
 This metal is obtained in Nature combined with sulphur. The ore 
 has much the resemblance of plumbago; but the metal itself is white, 
 resembling silver, and difficult to fuse. It is not soluble in dilute 
 acids, but dissolves readily in aqua regia. It combines with oxygen in 
 three proportions — 
 
 Protoxide = MoO. 
 
 Peroxide = Mo0 2 . 
 
 Molybdic acid...= MoC> 3 . 
 
 The protoxide is of a black colour; it is difficultly soluble in acids, 
 giving a black solution not crystallisable. 
 
 Peroxide of Molybdenum is obtained by digesting molybdic acid 
 with hydrochloric acid and copper; the solution has a deep-red colour, 
 and by adding to it an excess of ammonia, the copper is dissolved, and 
 the peroxide of molybdenum is precipitated. This oxide dissolves in 
 acids, forming salts which are red when crystallised, owing to the pres- 
 ence of water, but when rendered anhydrous, they become black. 
 
 Oxalic acid dissolves this oxide, and forms with it a salt which 
 crystallises in bluish-black crystals. These crystals are soluble in water, 
 and give a red coloured solution, to which, if ammonia be added, a red- 
 brown precipitate is obtained. 
 
 Molybdic Acid is obtained by roasting the native sulphide in the 
 air until all the sulphur is evolved; the acid remains as a powder. 
 When required pure, this powder is dissolved in ammonia, and the 
 solution is evaporated in order to crystallise the acid. The crystals 
 obtained are then submitted to a moderate heat to drive off the ammonia, 
 and the acid remains pure. It is slightly soluble in water, but combines 
 readily with the alkalies, forming salts, which are all soluble in water, 
 and all crystallise. By adding an acid to the solution of these salts, 
 the molybdic acid is precipitated. They act towards re-agents as 
 follows : — 
 
 Salts of lead, 
 
 Nitrate of silver, . 
 
 Persalts of iron, . 
 
 The salts formed by dissolving 
 re-agents as follows : — 
 
 Solution of galls, . 
 
 Red prussiate of potash, 
 Yellow prussiate of potash, . 
 Potash and soda, 
 
 Carbonates of the alkalies, . 
 Sulphides of the alkalies, 
 
 . White precipitate. 
 
 . White precipitate. 
 
 . Yellow precipitates. 
 
 the peroxide in an acid act towards 
 
 . Yellow precipitate. 
 
 * | Brown precipitates. 
 
 . Brownish-black precipitates. 
 
 . Light-brown precipitates. 
 
 . Brownish-yellow precipitates. 
 
172 
 
 ARSENIC. 
 
 Similar precipitates may be obtained from the salts of molybdic acid, by 
 adding, along with the re-agents, a little hydrochloric acid, to take up the 
 alkali of the salt. 
 
 Some years ago expectations were raised by the discovery of a large 
 quantity of native molybdate of lead, and the preparation of a compound 
 of molybdenum with phosphoric acid and ammonia, to be used in dyeing, 
 under the name of mineral indigo, but it failed in practice. 
 
 Tellurium (Te 128). 
 
 This is a metal which is found in combination with silver, bismuth, 
 and lead. Its colour is silver-white, its structure crystalline and brittle ; 
 it volatilises at a high heat, and bums in air with a blue flame ; its chemical 
 properties resemble sulphur. It combines with oxygen in two proportions, 
 both of which have acid properties : — 
 
 Tellurous acid = Te 203 H 2 . 
 
 Telluric acid = Te0 4 H2. 
 
 Tellurous Acid is a light, white, earthy powder, soluble in acids, and 
 also in the alkalies, with which it forms salts ( tellurites ), which are very 
 soluble in water, and easily decomposed. 
 
 Telluric Acid may be obtained by first fusing tellurous acid with 
 nitre, which gives tellurate of potash ; then, by dissolving this salt, and 
 adding a solution of barytes, there is formed an insoluble tellurate of 
 barytes, which is again decomposed by digestion in sulphuric acid ; the 
 sulphuric acid takes up the barytes, and the telluric acid remains in solu- 
 tion, and may be afterwards crystallised. A tellurate of soda and potash 
 may be formed by dissolving these alkalies in the acid : they are soluble in 
 water. 
 
 The action of re-agents upon the salts of tellurium is as follows 
 
 Alkalies, . 
 
 Yellow and red prussiate, . 
 Solution of galls, 
 
 Sulphides of the alkalies, . 
 
 White precipitates, redissolved. 
 No precipitate. 
 
 Yellowish precipitate. 
 Brownish precipitates. 
 
 Arsenic (As 75). 
 
 This metal is very abundantly distributed, in Nature, and is found in 
 various states of combination. It is chiefly, however, associated with iron, 
 nickel, and cobalt. Arsenic has a grey steel lustre, is brittle, crystalline, 
 and very easily volatilised, rising in vapour at a heat of about 356°, and is 
 thus easily separated from its ores. It combines with oxygen in three 
 
ARSENIOUS ACID. 
 
 173 
 
 different proportions : — First, a greyish oxide, probably suboxide, which 
 forms opon the surface of the metal by exposure to air ; and 
 
 Arsenious acid = As 2 0 3 . 
 
 Arsenic acid = As 2 0 5 . 
 
 Arsenious Acid. — This is plentiful in commerce as white arsenic ; it is a 
 heavy, white, opaque mass as sublimed, although generally sold in the market 
 as a powder or in crystals. This acid is dissolved by boiling water, in the 
 proportion of about 1 part to 10 of water ; but on cooling, the solution 
 deposits nearly three-fourths of this quantity. It has little, if any, taste, 
 but is notoriously a deadly poison. 
 
 The best antidote for arsenic when taken into the stomach, is newly- 
 precipitated peroxide of iron. This can always be obtained in a very few 
 minutes in the dye-house, by adding ~to the nitrate, or any other jser-solu- 
 tions of iron, a little ammonia, potash, or soda : the iron is immediately 
 precipitated. The precipitate ought first to be washed with water, and then 
 taken in the gelatinous state. The arsenious acid in the stomach receives 
 oxygen from the peroxide of iron, and is converted into arsenic acid, which 
 combines with the protoxide of iron, and is not poisonous. Should 
 arsenic be taken into the stomach in the state of arsenic acid, protoxide of 
 iron will serve the same purpose as the peroxide, and is obtained by pre- 
 cipitating some copperas by means of an alkali. At the same time medical 
 aid ought not to be neglected. 
 
 Arsenious acid dissolves in hydrochloric acid in much greater quantity 
 than in water, but does not combine with the acid (see Chlorine). It is 
 rapidly dissolved in hot solutions of bitartrate of potash, and forms a 
 crystallisable salt. It is dissolved also in great quantity by solutions of 
 potash and soda, and also, but not so effectually, by the carbonates of 
 these alkalies. 
 
 This acid, as before mentioned (page 146) is used in the dye-house for 
 dyeing Scheele’s green ( arsenic sages ) ; but not so much at the present time 
 as some years ago ; and there cannot be a doubt but that any process which 
 would supersede its use entirely would benefit all who are engaged in the 
 working with such goods. Common humanity, indeed, dictates its complete 
 abandonment as a dye, either on goods or paper. Nor is the evil so much 
 in the operations of dyeing as in those that succeed: persons who have 
 occasion to work with the yarns after they are dyed, suffer more severely 
 than the dyers. The colour being merely a precipitate of the arsenite of 
 copper (a most deadly poison) upon the fibre of the yarn, to which 
 much adheres loosely, and is readily disengaged as dust in the dry state, 
 especially in the process of winding, much of it is unavoidably inhaled 
 by the unfortunate operative. The result is, as might be expected, 
 that health is seriously impaired, and not unfrequently the consequences 
 are fatal. Warpers also are subjected to the same baneful evil, although 
 in a less degree ; and even the weaver is not exempt from it. Altogether, 
 
174 
 
 SULPHIDES OF ARSENIC. 
 
 indeed, the injury to the community by the use of this dye is as great 
 as that arising from the unrestricted sale of poisons, against which a legal 
 enactment was Shortly obtained. We are convinced, moreover, that it is 
 an unnecessary evil, and that dyers would very soon, under the pressure 
 of a little public opinion, find means of avoiding it, and producing a 
 similar colour innocuously and of an innocuous character. 
 
 This dye is still continued to be extensively used upon paper for rooms. 
 When used as flock it is very reprehensible, but even upon glazed paper it 
 is not safe. Only two years ago, a gentleman complained to us that for 
 several months he and his wife had got into a low state of health, and he 
 suspected the paper in his bedroom as the cause. We had a piece of the 
 paper to test, and found the green to be an arsenic green. The paper was 
 taken off, and another, not green, put on. They soon regained their 
 wonted health. This is only one case out of many that have come within 
 our notice. At the same time, while we believe that such dyes on paper 
 put on walls are hurtful, we must acknowledge that the amount of arsenic 
 given off under the circumstances must be exceedingly minute, and suggests 
 a still further inquiry into the effect of such infinitesimal quantities of dele- 
 terious substances taken into the system. 
 
 Arsenic Acid. — This acid is made by heating arsenious acid with 
 about its own weight of water, and when at the boiling point adding nitric 
 acid, as long as red fumes are given off : the whole is then evaporated to 
 dryness, to expel any excess of nitric acid that may be present. The heat 
 of the mass, when dry, must not be high, otherwise the arsenic acid will be 
 decomposed. Arsenic acid is milk-white, deliquesces, and is soluble in 
 water : its solution having a sour taste, and strong acid reactions. 
 
 When an equivalent of arsenic acid is ignited with an excess of car- 
 bonate of soda or potash, a subsalt is formed, which is soluble in water, and 
 easily crystallised. Salts of the alkalies are also formed by adding arsenic 
 acid to hot alkaline solutions. These salts crystallise, and their solutions in 
 water give white precipitates with the solutions of the earths and their salts. 
 Solutions of the salts of lead also give white precipitates ; nitrate of silver 
 a precipitate of a brown colour ; and salts of copper produce green pre- 
 cipitates. These salts can all be made available in the dye-house, although, 
 for the reasons above stated, it would be well if substitutes were used. 
 
 Sulphides of Arsenic. — There are two compounds of sulphur and 
 arsenic, which are, or rather were, occasionally used in the dye-house. 
 These are — 
 
 Kealgar ...= As 2 S 2 . 
 
 Orpiment = As 2 S 3 . 
 
 The first of these can be prepared by fusing arsenic, or arsenious acid, 
 with sulphur ; it is transparent, and of a fine ruby colour. 
 
 The latter may be prepared by adding to a solution of arsenious acid in 
 
ANTIMONY. 
 
 175 
 
 hydrochloric acid a sulphide of an alkali, either potash or soda; it is pre- 
 cipitated of a rich yellow colour, and is much used in painting, under the 
 name of king's yellow. 
 
 Both of these sulphides are found native. Their principal use in the 
 dye-house was in the blue vat, but they are seldom used now. 
 
 We remember seeing a beautiful illustration of the formation of these 
 two sulphides, realgar and orpiment. A large quantity of copper ore con- 
 taining arsenic was laid out upon a bed of cinders from the furnace, which 
 by some cause was set on fire, and the lower portion of the copper ore 
 subjected to great heat. A portion of the arsenic was sublimed in passing 
 through the mass of ore, in a crystalline state, both as realgar and 
 orpiment. Some beautiful crystalline specimens were obtained of these 
 sulphides. 
 
 Arsenic combines readily with hydrogen, and forms a gas, arseniuretted 
 hydrogen, which is very poisonous. When arsenic is present in any solution 
 from which hydrogen is being given off, arseniuretted hydrogen is formed, 
 and therefore care ought to be taken not to breathe any of the gas. From 
 this property of combining with hydrogen, the presence of arsenic in the 
 most minute quantity can be detected by putting a piece of pure zinc and 
 hydrochloric acid in the solution. Hydrogen is given off, which is passed 
 through a fine jet and burned by holding over the flame a piece of white 
 china ; if arsenic is present it gives a dark metallic spot on the china. 
 Sulphuric acid (see page 77) often contains arsenic. 
 
 Antimony (Sb 122-3). 
 
 This metal is found in considerable abundance associated with sulphur, 
 which is separated from it by roasting. Antimony is a bright and white 
 metal, of a crystalline structure, very brittle, and not oxidised by exposure 
 to the air. It volatilises at a high heat and oxidises or burns at a red heat, 
 when exposed to the air : it then passes off in white fumes. Antimony 
 combines with oxygen in three proportions, forming — 
 
 Oxide of antimony, = Sb 2 0 3 . 
 
 Antimonious acid, = Sb 2 0 4 . 
 
 Antimonic acid, — SbsOs. 
 
 Oxide of Antimony may be prepared either by sublimation, as already 
 stated, or by precipitation from a solution of any of its salts, by an alkali. 
 
 When the sulphide of antimony (the common ore) is digested in 
 strong hydrochloric acid, the metal dissolves, and forms a chloride of 
 antimony, or rather a terchloride, as follows : — 
 
176 
 
 URANIUM. 
 
 Sulphuret of antimony, . 
 
 (S 
 
 <Sb 2 
 
 3 Sulphide hydrogen gas. 
 
 Six proportions of hydro- 
 
 (611 
 
 . Terchloride of antimony, 
 
 chloric acid, 
 
 (6 Cl 
 
 or trichloride. 
 
 The clear solution being poured off, and heated to the boiling point, 
 carbonate of potash or soda is then added, and the antimony is precipitated 
 in the state of oxide as a white powder. Both potash and soda dissolve 
 this oxide. 
 
 Sulphate of Antimony may be prepared by digesting the sulphide in 
 strong sulphuric acid with the aid of heat ; or the metal may be substituted 
 for the sulphide. 
 
 All the acid salts of antimony are decomposed by aqueous dilution ; 
 an insoluble oxychloride is thereby formed and precipitated as a white 
 powder, except there be an excess of acid. There are, however, several 
 double salts of antimony with other substances, which are soluble, and not 
 precipitated by dilution. Thus, when a strong solution of binoxalate of 
 potash is heated, and oxide of antimony added, a salt is formed, which is 
 soluble in water, and from which the antimony is not precipitated by 
 dilution. Again, when oxide of antimony is boiled in water, and tartrate 
 of potash added, a double salt (tartar emetic) is formed, which crystallises, 
 and is not precipitated by dilution. 
 
 Antimonious Acid is obtained by oxidising or acting upon metallic 
 antimony with nitric acid. It is also formed when sulphate of antimony is 
 roasted. Some doubts exist as to the true nature of this compound; it is 
 probably a mixture of oxide of antimony with antimonic acid (thus 
 Sb 2 0 3 + Sb 2 0 5 ), having the same elements as two proportions of anti- 
 monious acid = Sb 2 0 4 . By heating any of these two oxides in a current 
 of air, Sb 2 0 4 is formed. 
 
 Antimonic Acid is prepared in the same manner as described for 
 arsenic acid — that is, by acting upon the oxide with nitric acid, and 
 expelling any excess of the acid by heat. Antimonic acid is a pale-yellow 
 powder, not soluble in water, but soluble in potash and soda, with which 
 it forms antimoniates, which, however, are not stable, and are decomposed 
 by almost any other acid or salt. 
 
 The precipitates formed by re-agents with salts of antimony are nearly 
 all white, but when a sulphide of any of the alkalies is added to a solution 
 of antimony, a beautiful golden yellow precipitate is formed. 
 
 Uranium (U 120). 
 
 This rare metal is a component of the mineral named pitchblende, 
 which contains several other metals. Its metallic characteristics have not 
 
PEROXIDE OF URANIUM. 
 
 177 
 
 been long known ; indeed, one of its oxides was a long time regarded as 
 an element. It is a white coloured metal, very like silver, but is peculiar 
 in being very inflammable, burning with great brightness at a low red heat- 
 It combines with oxygen in several proportions, but only two of its oxides 
 are soluble in acids, and form corresponding salts. These are the 
 
 Protoxide = UO. 
 
 Peroxide = U 2 0 . 
 
 Protoxide of Uranium is obtained by acting upon the mineral above- 
 named, by aqua regia, and separating it from the various other metals with 
 which it is associated, by precipitation. When a solution of uranium in an 
 acid is precipitated by an alkali, and the alkali is well washed out, the 
 remainder is in the state of protoxide. This oxide dissolves with difficulty 
 in hydrochloric acid, but more freely in dilute sulphuric acid with the aid 
 of heat, and gives a green solution, which yield's similarly coloured crystals. 
 It is used for giving a deep black to china. It is very soluble in nitric 
 acid, forming a nitrate. These salts give the following reactions : — 
 
 Alkalies, .... Brownish precipitates. 
 
 Carbonates of the alkalies, . Greenish precipitates. 
 
 Yellow prussiate of potash, . Reddish-brown precipitate. 
 
 Red prussiate of potash, . Reddish-brown precipitate, after a time. 
 
 Sulphides of the alkalies, . Black precipitates. 
 
 Peroxide of Uranium, or sesquioxide, is obtained by precipitation 
 from a solution of the mineral by means of an alkali; the precipitate 
 is collected, but the alkali is not washed out, and it is exposed to 
 a red heat. When thus treated the oxide is stable. The presence of 
 alkali is considered necessary, so that ammonia will not serve as the 
 precipitant in this case ; on account of its volatile nature, it would be 
 dissipated by the heat to which the precipitate must be exposed. 
 
 The peroxide of uranium has a beautiful yellow colour, and is soluble 
 in all the acids, forming persalts. The solutions of these salts act to- 
 wards re-agents as follows : — 
 
 Alkalies and their carbonates, 
 Yellow prussiate of potash, 
 Red prussiate of potash, . 
 Solution of galls, 
 
 Sulphides of the alkalies, . 
 
 Yellow precipitates. 
 Reddish-brown precipitate. 
 No precipitate. 
 
 Dark brown precipitate. 
 Brown precipitates. 
 
 It may be inferred from these reactions, that could this metal be 
 obtained in sufficient quantity, it would form a valuable addition to the 
 dyer’s colouring matters. At present, however, it is too scarce to be 
 regarded as of any practical importance. It is used for giving glass a 
 peculiar yellow colour, which is fluorescent. 
 
 M 
 
178 
 
 PROTOXIDE OF MERCURY. 
 
 Cerium (Ce 92). 
 
 This metal is obtained in small quantities from several minerals, found 
 chiefly in Sweden and Greenland. These are acted upon by aqua regia , 
 and the metal is separated by re-agents. Hitherto it has been obtained 
 only as a powder of a brownish-black colour, which is rapidly decomposed 
 in water. With oxygen it forms 
 
 Protoxide = CeO. 
 
 Peroxide = Ce 2 0 3 . 
 
 The oxides and salts of cerium are mostly white, but have not been 
 subjected to any close investigation. Re-agents generally give white 
 precipitates with solutions of the salts. 
 
 Mercury (Hg 200). 
 
 This metal is found abundantly both in the metallic state and in 
 combination with sulphur, forming the mineral cinnabar , from which the 
 metal is distilled, by heating it with iron and lime. Mercury at ordinary 
 temperatures is liquid : hence its popular name of quicksilver ; it has a high 
 metallic lustre, becomes solid at 40° below zero, and gaseous at 662°. It 
 combines with oxygen in two well-known proportions — 
 
 Suboxide, or black oxide, = Hg 2 0. 
 Protoxide, or red oxide, = HgO. 
 
 Suboxide of Mercury is a black powder, and is obtained by pre- 
 cipitation from a cold solution of calomel by potash or soda. It dissolves 
 in acids, and forms a series of salts of great use in medicine. The common 
 calomel of the druggists is a chloride of mercury = HgCl. These salts of 
 mercury give the following reactions : — 
 
 Alkalies, . . . . Black precipitates. 
 
 Carbonates of the alkalies, White precipitates, which become black 
 
 by heating. 
 
 White precipitate. 
 
 Reddish-brown precipitate. 
 
 Light yellow precipitate. 
 
 Red precipitate. 
 
 Plack precipitates. 
 
 Yellow prussiate of potash, 
 Red prussiate of potash, .. 
 Solution of galls, 
 Bichromate of potash. 
 Sulphides of the alkalies, . 
 
 Protoxide of Mercury, Peroxide of Mercury, or Red Oxide. — This 
 oxide is obtained by heating mercury in contact with oxygen, or by expos- 
 ing nitrate of mercury to heat until all the acid is expelled. Its colour is a 
 deep red, and hence it is known in commerce as red precipitate. 
 
 When mercury is acted upon by an acid, persalts are generally formed. 
 These salts may also be formed by dissolving the red oxide in the acids. 
 Thus the perchloride (corrosive sublimate) (HgCl 2 ) may be prepared by 
 
SILVER. 
 
 179 
 
 dissolving the red oxide in hydrochloric acid. There are a great variety of 
 salts of mercury, nearly all poisonous, and all less or more used in 
 medicine. None of them are used in dyeing, but some are useful as tests. 
 The following are their reactions with other substances : — 
 
 Potash and soda, 
 Ammonia, 
 
 Carbonates of the alkalies, 
 Carbonate of ammonia, 
 Yellow prussiate of potash, 
 Red prussiate of potash, 
 Solution of galls, . 
 
 Iodide of potassium, 
 Bichromate of potash, . 
 Sulphides of the alkalies, 
 
 . Yellow precipitates. 
 
 . White precipitate. 
 
 . Reddish-brown precipitates. 
 . White precipitate. 
 
 . White precipitate. 
 
 . Yellow precipitate. 
 
 . No precipitate. 
 
 . Red precipitate. 
 
 . Red precipitate. 
 
 . Black precipitates. 
 
 These colours are not permanent when dyed upon cotton — they are 
 destroyed when exposed to a moderate heat. 
 
 Silver (Ag 108). 
 
 This metal is found in considerable abundance in Nature, and is very 
 widely diffused: it is generally in combination with sulphur, along with 
 other metals, particularly with lead. It is obtained from the lead ores 
 of this country, and is extracted from them by cupellation, as was de- 
 scribed under the heading Litharge (page 147). It is also extracted from 
 its sulphides, and from some other ores which are found abroad, from 
 which the greater quantity of the silver is obtained, by roasting the ore, 
 after mixing with it a quantity of common salt, which converts the silver 
 into a chloride. The ore is next put into large barrels with water and 
 scraps of metallic iron and mercury, and the barrels are kept revolving in 
 order thoroughly to mix their contents. The iron decomposes the chloride 
 of silver, and becomes a chloride of iron, and the mercury takes the 
 liberated silver, and forms with it an amalgam. The reactions may be 
 
 thus represented: — ■ 
 
 
 
 Two chloride of 
 
 f Ag 2 . 
 
 . Amalgam of silver. 
 
 silver, 
 
 \ CW. . ^ 
 
 
 Mercury, 
 
 ...Hg.. 
 
 
 Iron, 
 
 ...Fe.. _ 
 
 ■'Chloride of iron, soluble. 
 
 The amalgam is collected and subjected to a high heat in a retort ; the 
 mercury is thereby distilled over, and the silver remains behind. 
 
 Silver is the whitest of all the metals ; it is also highly ductile and 
 malleable, and does not combine with oxygen by exposure to the air, but 
 is very soon tarnished by the fumes^of sulphur, which always exist to some 
 
180 
 
 SULPHATE OF SILVER. 
 
 extent in localities where coal is burned. Silver combines with oxygen 
 in three proportions — 
 
 Sub oxide = Ag 4 0. 
 
 Protoxide = Ag 3 0. 
 
 Peroxide = Ag 4 0 4 , or 2 Ag 2 0 2 . 
 
 The first and last of these oxides are little known; the protoxide is of the 
 most importance, and is obtained as a deep-brown powder, by adding 
 an alkali to the solution of any soluble salt of silver. This oxide dis- 
 solves in acids, and forms protosalts. 
 
 Nitrate of Silver. — Nitric acid diluted dissolves silver by the aid 
 of heat with great ease ; and the nitrate formed is the salt commonly used 
 in the laboratories. It is very corrosive, blackens the skin, and constitutes 
 the permanent marking ink for linen, which, by the way, may be easily 
 obliterated by dipping the cloth in chlorine water. The chlorine converts 
 the silver into a chloride, which may be washed out by passing the 
 cloth through liquid ammonia. Nitrate and chloride of silver are exten- 
 sively used for photographical purposes, and the study of the action of light 
 upon these salts is indeed well worthy the attention of dyers (page 12), 
 as the phenomena are highly suggestive of many changes observed in 
 dyed colours. 
 
 Sulphate of Silver. — Silver is dissolved by hot sulphuric acid, and 
 forms a sulphate of silver. This salt crystallises, and is very corrosive, 
 but it is little used. 
 
 The attraction of silver for chlorine is so great that hydrochloric acid, 
 or any chloride, added to a salt of silver, instantly decomposes it, and 
 converts the silver into an insoluble chloride. Hence it is that chlorides 
 are the best tests for silver, and that silver is in turn the best test for 
 chlorine. 
 
 Oxide of silver is soluble in acetic acid and many of the milder acids. 
 
 Chloride of silver is soluble in hyposulphite of soda, and is used in 
 photography for dissolving off the silver which has not been acted on by 
 light. 
 
 When experimenting with salts of silver, it is of course important 
 that none of the metal be lost; it can be all recovered by converting it 
 into chloride, evaporating or filtering the solution, and when the chloride 
 is dry, mixing it with three times its weight of dry carbonate of potash; 
 putting this into a crucible, and fusing for fifteen minutes: when the 
 crucible cools, the metallic silver will be found as a button of metal at 
 the bottom. 
 
 The salts of silver have the following reactions with other sub- 
 stances : — 
 
 Potash and soda, . . . Brown precipitates. 
 
 Ammonia, Brown precipitate, very soluble in 
 
 excess. 
 
CHLORIDE OF GOLD. 
 
 181 
 
 Carbonates of the alkalies, 
 Yellow prussiate of potash, 
 Red prussiate of potash, 
 Solution of galls, 
 Bichromate of potash, 
 Sulphides of the alkalies, . 
 
 White precipitates. 
 White precipitate. 
 Red-brown precipitate. 
 No precipitate. 
 
 Crimson -red precipitate. 
 Black precipitates. 
 
 The necessary expense of this metal prevents the introduction of its 
 salts to the dye-house ; and we are afraid that the property of becoming 
 black by exposure to light would destroy their general usefulness, even 
 could they be had sufficiently cheap. 
 
 Gold (Au 197> 
 
 This metal is commonly found in the metallic state nearly pure, but 
 sometimes it is associated with other metals; it is extensively diffused 
 through Nature. When it is found along with silver, in what is termed 
 silver ore , the ore is treated in the same way as described for ores of silver, 
 and the two metals are obtained together in alloy; but when the metal is 
 diffused through the rock in the metallic state, in grains or nuggets, the 
 rock is stamped to fine powder, and then submitted to a current of water, 
 which carries away the light earthy portion, and the gold falls to the 
 bottom from its superior weight. This residuum is mixed with metallic 
 mercury, to form an amalgam with the gold, which is afterwards distilled 
 in the same manner as was described for silver. 
 
 Gold and silver are separated by subjecting the alloy to the action of 
 nitric or strong sulphuric acid, which dissolve the silver and leave the 
 gold — an operation which is termed parting. The silver is afterwards preci- 
 pitated as a chloride, and reduced by fusion with carbonate of potash. 
 
 Gold is the only yellow metal known; it is the most ductile as well 
 as the most malleable of the metals, and does not oxidise or tarnish by 
 exposure to the air, which gives it an intrinsic value over most of the 
 other metals. It does not dissolve in any single acid, but is readily acted 
 upon by aqua regia, forming a perchloride. It combines with oxygen in 
 two proportions — 
 
 Sub oxide = Au 2 0. 
 
 Peroxide = Au 2 Os. 
 
 The first of these oxides is obtained by adding a solution of potash 
 to subchloride of gold : it is a green powder. 
 
 The peroxide is obtained by precipitating the solution of gold in aqua 
 regia by magnesia, and washing the precipitate with a little nitric acid. This 
 oxide is of a brown colour. 
 
 Chloride of Gold is prepared by evaporating a solution of gold in 
 
182 
 
 PLATINUM. 
 
 aqua regia to dryness, and heating the residue to about 400°, until all 
 smell of chlorine has ceased, stirring all the while. The product is the 
 chloride, and is decomposed by water. 
 
 Perchloride or Trichloride of Gold. — This is the salt obtained by 
 dissolving the metal- in aqua regia,- 
 
 Peroxide of gold, 
 
 Six hydrochloric acid, 
 
 Perchloride of gold, AuC1 3 . 
 
 § Water =H 2 0. 
 
 This salt is yellow, but when it touches the skin it dyes it of a deep 
 
 purple. Its reactions are as follow : — 
 
 Potash and soda, 
 
 Ammonia, ..... 
 Oxalic acid, .... 
 Yellow prussiate of potash, 
 
 Red prussiate of potash, 
 Protosalts of iron, 
 
 Protosalts of tin, 
 
 Solution of galls, 
 
 No precipitate. 
 
 Yellow precipitate. 
 
 Dark-green precipitate. 
 Light-green precipitate. 
 
 No precipitate. 
 
 Brown (metallic gold) precipitates. 
 Purple precipitates. 
 
 Black precipitate, which becomes 
 brown (metallic gold). 
 
 Salts of this metal, on account of their expense, can only be used as 
 re -agents in the laboratory, not in manufacturing operations. 
 
 Platinum (Pt 197). 
 
 This metal is found in a native state in the debris of rocks belonging to 
 the earliest igneous formation. It was first discovered in the auriferous 
 sands of some rivers in America, but is now found in various localities. 
 Platinum is a white metal, very ductile, and also malleable; it is the 
 densest metal known, and is not acted upon by exposure to the air, nor 
 oxidised by heat. No single acid affects it, on which account it is exceed- 
 ingly useful in many chemical processes. Aqua regia dissolves it with the 
 aid of heat, and forms with it a perchloride. It combines with oxygen in 
 two proportions — 
 
 Protoxide = PtO. 
 
 Peroxide = Pt0 2 . 
 
 The protoxide is obtained by digesting the protochloride in potash ; 
 it is a black powder, soluble in excess of potash, yielding a green solution, 
 from which the platinum may be precipitated. 
 
 The protochloride is obtained in the same manner as the protochloride 
 of gold ; it is a greenish powder, slightly soluble in strong hydrochloric 
 acid. 
 
PALLADIUM'. 
 
 183 
 
 The peroxide of platinum is obtained by adding to a solution of sul- 
 phate of platinum some nitrate of barytes : the sulphuric acid is precipitated, 
 and nitrate of platinum is formed, and remains in solution. By adding to 
 this solution a little soda, peroxide of platinum is precipitated as a reddish- 
 brown powder. This oxide dissolves in acids, forming salts, which are 
 mostly of a brownish-red colour, and has a strong attraction for the 
 earthy bases. 
 
 The sulphate is prepared by adding to a solution of platinum in aqua 
 regia , drop by drop, a solution of sulphide of potassium, which forms a 
 bisulphide of platinum ; by exposure to the air the sulphur attracts oxygen, 
 and becomes sulphuric acid, which combines with the metal. 
 
 Bichloride of platinum is the salt formed when the metal is dissolved 
 in aqua regia ; it has a deep-red colour. This salt combines with chloride 
 of potassium, and forms with it a double salt, which crystallises in beautiful 
 reddish-yellow crystals, insoluble in alcohol, and is on that account used 
 for separating potash from other substances. The persalts of platinum are 
 all more or less red in colour, and have the following reactions with other 
 substances : — 
 
 Potash, soda, ammonia, and their car- 1 
 
 bonates, .) 
 
 Yellow prussiate of potash, 
 
 Red prussiate of potash, . 
 
 Solution of galls, .... 
 Protochloride of tin, .... 
 
 Sulphides of the alkalies, .. 
 
 Yellow precipitates. 
 
 Yellow precipitate. 
 
 Yellow precipitate. 
 
 No precipitate. 
 
 A reddish-brown coloured solu- 
 tion, the tin being rendered a 
 perchloride, the platinum a 
 protochloride, but there is no 
 precipitate. 
 
 Reddish-brown precipitates. 
 
 Palladium (Pd 106-6). 
 
 This metal is found associated with platinum ; its appearance is very 
 similar, except that it has a slightly reddish tint, and only about half the 
 density. It is nearly as infusible, but its surface slightly tarnishes by 
 exposure to air, and it is soluble in nitric acid. Like platinum, it combines 
 with oxygen in two proportions — 
 
 Protoxide = PdO. 
 
 Peroxide = Pd0 2 . 
 
 The protoxide is a dark-brown powder, and is obtained by dissolving 
 the metal in nitric acid, evaporating to dryness, and heating the residue to 
 drive off the acid; or it is precipitated from the acid by an alkaline solution. 
 
 The protochloride of palladium is formed by dissolving the metal in 
 
184 
 
 RHODIUM. 
 
 hydrochloric acid, to which a few drops of nitric acid have been added. 
 The former acid acts upon the metal slowly when alone, but this addition 
 quickens the action. The solution is evaporated to dryness, to expel any 
 excess of acid, and yields a compound of a dark -brown colour, which is 
 protochloride. This salt combines with chloride of potassium and sodium, 
 and forms double salts, which deposit yellow-coloured crystals from their 
 solutions. 
 
 The peroxide of palladium is obtained by first dissolving the metal in 
 strong aqua regia-: this gives a solution of a dark-brown colour, which is a 
 bichloride of the metal. To this solution is added, gradually , either potash 
 or soda, which precipitates the metal as a hydrated peroxide of a reddish- 
 brown colour. The salts corresponding to the peroxide are little known. 
 Solutions of the protosalts of palladium act towards re-agents as under : — 
 
 Potash -and soda, ..... 
 Ammonia, -. .... 
 
 Carbonates of potash and soda, 
 Yellow and red prussiates of potash, 
 Protochloride of tin, 
 
 Phosphate of soda, .... 
 Sulphides of the alkalies, . 
 
 Brownish precipitates. 
 No precipitate. 
 
 Brown precipitates. 
 No precipitates. 
 
 Black precipitate. 
 Brown precipitate. 
 Black precipitates. 
 
 Iridium (Xr 197). 
 
 This mertal is found combined with platinum, and, like palladium, 
 resembles it in appearance. It is more infusible than platinum, and, if 
 pure, resists the action of all the acids ; but when alloyed with platinum it 
 is soluble in aqua, regia. It is known to combine with oxygen in three pro- 
 portions, to all of which there are corresponding chlorides known. The 
 salts of this metal are mostly of a rose colour, and insoluble, or nearly so, 
 in water. They are of no known practical value. 
 
 Osmium (Os 199). 
 
 This metal is always found associated with iridium in platinum, and is 
 obtained in a pulverulent state. It is the most infusible of the metals. It 
 dissolves when alone in strong nitric acid and aqua regia — in both cases 
 forming osmic acid. If combines with oxygen in different proportions. 
 When the metal is heated in a current of air, it forms a volatile oxide, 
 OSO4, soluble in water. The oxides of this metal are nearly all brown. 
 There are also corresponding chlorides, which are generally coloured. 
 
 Rhodium (R 104-2). 
 
 This is another metal found alloyed with platinum, which it resembles 
 in appearance, but is brittle and hard. If pure, it is not acted upon by any 
 
LANTHANIUM. 
 
 185 
 
 of the acids, but when alloyed with another metal, as with platinum, it 
 readily dissolves in aqua regia . Soda precipitates both metals from this 
 solution ; but the platinum precipitate is soluble in alcohol, and is thus 
 easily separated. The rhodium in this state is of a beautiful rose colour, 
 and combines with oxygen in two proportions — 
 
 Protoxide = RO. 
 
 Peroxide = R2O3. 
 
 The protoxide has not been isolated: the peroxide is a black powder. The 
 salts are all less or more coloured, and generally give coloured precipitates 
 with re-agents. Rhodium has been introduced into the arts on account of 
 its giving great hardness to metals alloyed with it. It is used for tipping 
 metallic (gold and silver) writing pens, &c. 
 
 Lanthanium (La 93). 
 
 This metal was discovered in a mineral from which cerium is obtained. 
 Its oxide has a brick-red colour, and dissolves in acids, giving red-coloured 
 salts. 
 
 Along with this metal another was detected by the same discoverer : it 
 is named Didymium, and very much resembles lanthanium in its chemical 
 properties. 
 
 There are other three rare metals — 
 
 Erbium , Niobium , Ruthenium — 
 
 requiring no further notice than their names, and it is probable that some 
 of these may yet be found to be combinations of other metals ; but until 
 that is proved we must look upon them as elements as yet too rare to be 
 of any value to the manufacturer. 
 
 In the preceding sketch of the elements we have treated very briefly 
 all those which have not yet had any practical application to the art of 
 dyeing, and also those that are rare and expensive. Of those elements, 
 we have noticed merely the features and reactions which seemed to us 
 best calculated to attract attention, or which might suggest experiments, 
 with a view to their application in the dyeing trade. And although many of 
 the metallic elements, which give indications of available properties, are at 
 present too rare to be employed, yet we know not how soon the rarest of 
 them may be discovered in abundance ; and it is a law, quite as certain as 
 gravitation itself, that if a demand be created exertion will follow to satisfy 
 it. When chromium was first discovered it was considered a rare metal, 
 but, as the demand grew, other ores were found to contain it in great 
 abundance ; and so it may be with some of those metals now considered 
 the most rare and unlikely ever to become abundant. 
 
MORDANTS. 
 
 If the various colouring matters used in dyeing had an affinity for 
 the fibre the process would be very simple : it would only be necessary 
 to make a solution of the dye-drug, and immerse the goods in it to 
 ensure their being dyed. But so far from this being the case, if we 
 except indigo and safflower, there is scarcely a dye-stuff that imparts its 
 own colour to goods ; nay, the greater part of the dye-drugs used have so 
 weak an affinity, especially for cotton goods, that they impart no colour 
 sufficiently permanent to deserve the name of a dye. The cause of this is 
 obvious. If, for example, we take a decoction of logwood, the colouring 
 matter is held in solution by the water ; by putting a quantity of cotton 
 into this solution the fibres become filled with the coloured solution, but 
 if the cotton has no power to render that colouring matter insoluble, and 
 retain it within its fibres, it is plain that, by taking out the cotton and 
 putting it into water, the colouring matter within and upon it will be 
 diffused in the water — in other words, the dye having no attraction for 
 the fibre, is washed out. This want of affinity makes dyeing sufficiently 
 intricate, and renders it more dependent upon science ; indeed, it is only 
 by the nicest arrangement of a few chemical laws that the dyer is enabled 
 to turn to advantage the various colouring matters of which he is in pos- 
 session. When the dyer finds that there is no affinity between the goods 
 and any colouring substance which is put into his possession, he endea- 
 vours to find a substance which has a mutual attraction for the cloth 
 and colouring matter, so that by combining this substance with the cloth, 
 and then passing the cloth through the dyeing solution, the colouring 
 matter combines with the substance which is upon the goods, and con- 
 stitutes a dye. This third substance used, which acts as a mediator, com- 
 bining two inimical bodies, is termed a mordant, from the French mordre, 
 to bite — from an idea which the old dyers had that these substances bit or 
 opened a passage into the fibres of the cloth, giving access to the colour. 
 And although the theory of their action is now changed, the term is still 
 continued, and perhaps further investigation will prove the term not 
 altogether inapplicable. 
 
 All the mordants, with one or two exceptions, are found among the 
 metallic oxides. It may be supposed from this that, as metals are the 
 most numerous class of elements, mordants are also very numerous ; it is 
 not so, however. In order that the substance may act as a mordant, it 
 must possess certain properties : it must have an attraction for the colour- 
 ing matter, so as to form with it an insoluble coloured compound ; and it 
 must be held easily in solution in order to enter within the fibre. It may 
 
MORDANTS. 
 
 187 
 
 also have an affinity for the fibre, a tendency to unite with it, but this 
 property is not essentially necessary; only the two first properties are 
 so, and they limit the mordants almost wholly to what are termed the 
 insoluble bases — that is, substances which are not by themselves soluble 
 in water. 
 
 The bases or oxides which are in general use as mordants,' and which 
 appear to succeed best, are alumina and the oxides of tin and iron; the 
 two first are colourless, and the peroxide of the latter is brown, and 
 imparts to white goods a buff or nankeen colour, which in many cases 
 affects to a considerable extent the colour of the cloth, a circumstance 
 which must also be attended to by the dyer. Indeed, the principal part of 
 all dyeing operations is the proper choice and application of mordants ; 
 there being a chemical union between them and the colouring matter, a 
 new substance is formed, not only differing in properties, but differing in 
 colour, from any of the originals, consequently a very little alteration in 
 the strength or quality of a mordant gives a decided alteration in the 
 shade of colour. However, this gives the dyer a much wider field for 
 variety of shades, and at the same time a less number of colouring sub- 
 stances are required ; as, for example, logwood alone gives no colour to 
 cotton worthy the name of a dye ; yet by the judicious application of a few 
 different kinds of mordants, all the shades from a French white to a violet, 
 from a lavender to a purple, from a blue to a lilac, and from a slate to a 
 black, are obtained from this substance. 
 
 Before any chemical union takes place between bodies, they must not 
 only be in contact, but they must be brought into contact element with 
 element, or particle with particle; hence, substances used as mordants that 
 are insoluble of themselves in water must be dissolved in some appropriate 
 menstrua before their particles can enter the fibres of the goods, or com- 
 bine with the colouring matter. In doing this, the dyer has often to attend 
 to the degree of affinity between the solvent and the mordant, to determine 
 what force it will exert to prevent the mordant combining with the fibre ; 
 should there exist an affinity between them, an otherwise excellent mordant 
 may be less effective by the attraction of its solvent ; as an example, 
 common alum, even though much concentrated, is but a weak mordant for 
 cotton goods, owing to the great attraction between the sulphuric acid and 
 the alumina. But if acetic acid, which has comparatively a weak affinity 
 for the alumina, be substituted for the sulphuric acid, it becomes a very 
 much more effective mordant. From these things having to be attended 
 to, the dyer has many beautiful illustrations of the relative attraction of 
 different substances for each other. In some cases the dyeing compound 
 formed between the mordant and colouring matter being soluble may be 
 kept mixed, and the goods, when immersed in this solution, having a kind 
 of reciprocal affinity, only receive their share, they do not extract the 
 colouring matter from the solvent, but the depth of colour upon the cloth 
 depends upon the colour of the solution. In other cases the attraction 
 between the mordant solution and colouring matter is so powerful, that if 
 
188 
 
 MORDANTS. 
 
 the least quantity of the mordant solution be left upon the cloth when put 
 into the dye, it seizes the colouring matter, which it instantly precipitates 
 or renders it insoluble, and therefore unfit to combine with the goods, 
 not only causing loss, but the colour will be uneven; in this case, 
 the goods passing through the mordant have a part of the base 
 fixed in the fibre, they are then washed, or the solvent of the mordant 
 otherwise removed. From these circumstances, the close alliance of 
 the art of dyeing to the science of chemistry is evident; but an 
 individual from experience may know these effects, and, though ignorant 
 of the cause, may often guard against their consequences ; knowledge, 
 however, procured only by routine practice, is purchased at a very great 
 cost, and attended with many unpleasant circumstances. In cases where 
 the base has no affinity for the fibre, there exists the same difficulty, 
 the fibre being filled with the solution of the base ; should the goods 
 so filled be passed through water, the base will be washed out; and 
 should they be put into the dyeing solution, a great quantity of the colour- 
 ing matter will be precipitated upon the fibre, not within it, and will thus 
 be left merely adhering to the surface, and, when dry, much of it will of 
 course come off as dust, which is so much loss. For example, the simple 
 protosalts of lead have little or no affinity for the fibre, and if cotton im- 
 pregnated with nitrate or acetate of lead be washed several times, nearly 
 the whole lead salt is dissolved out. If put through the bichromate of pot- 
 ash solution directly from the lead, a great quantity of chromate of lead will 
 fall to the bottom of the tub and be lost ; but by passing the goods from 
 the lead solution through a little lime-water, the lime takes away the acid, 
 the lead is fixed within the fibre as an oxide, and when put into the chrome 
 solution combines with the chromic acid, and no chromate of lead is preci- 
 pitated. Nevertheless there are colouring matters that require a little of the 
 free mordant to be added to bring out the colour. Thus, a piece of cotton 
 passed through red spirits, and then well washed in water, will retain a great 
 part of the oxide of tin. Let the cotton be put into a solution of logwood, 
 this will combine with the base or oxide of tin, and leave the water of the 
 decoction nearly colourless, giving a reddish-brown colour to the goods 
 without brilliancy, and not suitable as a dye ; but by adding a small quan- 
 tity of spirits to this exhausted water, and then immersing the dyed cotton 
 again, instantly the true violet or purple colour is brought up. The 
 substances thus added to the coloured liquor to change the colours are 
 termed alterants , and the operation, in the language of the dye-house, 
 raising , because it brightens the colour. Alterants and mordants are often 
 spoken of as two distinct kinds of substances ; but the only distinction is in 
 the mode and time of applying them. In some instances different substances 
 are used. In the process detailed above, a little alum would do as well as the 
 salt of tin ; or if a particular bluish shade were wanted, a little pyrolignite 
 of alumina: but in almost all cases the mordant may also be used as the 
 alterant. This shews that in some instances the dye may require some 
 of the acid in the salt which constituted the mordant to bring it out, and 
 
MORDANTS. 
 
 189 
 
 must be applied after the colour is fixed. If in the above operation the 
 cloth had been passed through the hot logwood solution directly from the 
 spirit tub, a great part of the logwood would have been precipitated, and 
 unless the decoction had been very strong, the colour upon the fibre would 
 have been weak and unequal. Other matters are often added as a sort of 
 alterant in some colours, not to affect the required change of the colour, 
 but to take up some substance that may have a tendency to retain the 
 colouring matter, and prevent its uniting with the mordant. Thus it may 
 be necessary with lead mordants, where the acid of the lead is taken away, 
 to add some acid to the chrome solution to combine with the potash, in 
 order to liberate the chromic acid, and allow it more freely to take the lead. 
 This is particularly the case with Prussian blue. If the goods are washed 
 from the nitrate of iron solution, or passed through an alkali, a little acid 
 must be added to the prussiate of potash solution, to take the potash and 
 liberate the prussic acid. 
 
 It is with the vegetable colouring matters, however, that the greatest 
 attention must be paid to the many conditions and properties of mordants : 
 some of these may be shortly noticed. 
 
 The mordant, or solvent of the base constituting the mordant, should 
 not be capable of injuring or destroying immediately, or by prolonged 
 action, either the colouring matter or the fabric. Thus, acids alone do not 
 serve as mordants, as they generally either destroy the fabric or the colour- 
 ing matter; and in cases where destructive acids are used for dissolving the 
 base, care has to be taken that they are washed off or neutralised before 
 they have had time to act upon the tissue or upon the colour. The action 
 of bases upon colours, and the condition of those best adapted to give 
 beauty and permanency, are most important subjects, and deserve that we 
 should here consider them a little in detail. 
 
 1. The base being insoluble in water, has to be rendered soluble by 
 combining it with an acid, so as to allow the base to combine with the 
 colouring matter. What becomes of that acid which holds the base in 
 solution when the colouring matter combines with the base? Will it act 
 upon the colour formed? We have already discussed this point as regards 
 lead and chrome (page 167) ; we will now take another colour, which, 
 although strictly speaking it does not embrace the action mordant, will 
 serve very well to illustrate the point of inquiry. Indigo is insoluble in 
 water, but is dissolved in strong sulphuric acid, forming sulphate of indigo, 
 and is used for dyeing green upon light cotton cloths. The goods are first 
 dyed yellow by a decoction of quercitron bark or fustic, and then dyed 
 blue by means of sulphate of indigo, which gives green. Now, were the 
 yellow dye passed through the sulphate of indigo as made, the acid would 
 destroy the yellow and spoil the colour; the acid has, therefore, first to be 
 neutralised by an alkaline substance. If soda or potash be used, we have 
 the sulphate of the alkali held in solution with the indigo ; and although 
 the acid will not now destroy the yellow, there is another consideration — 
 namely, the effect of this sulphate of the alkali upon the yellow colour; 
 
190 
 
 MORDANTS. 
 
 and if there be an effect, it becomes a question how to avoid it. Thus, 
 every circumstance produces a new feature, and should be fully studied. 
 Where fine clear shades of green are required, the sulphates of the alkalies do 
 affect the yellow dye, giving what the dyer calls a rusty tint; this is avoided 
 by using carbonate of lime (chalk) instead of soda or potash, forming sul- 
 phate of lime, which precipitates, leaving a clear blue solution of the indigo ; 
 in any case neither acid nor alkali should prevail. 
 
 2. We must consider the nature and properties of the base con- 
 stituting the mordant, and its reaction upon the colouring matter, both 
 in combining together, and afterwards under exposure to the air. Thus 
 we have stated, when treating of the oxides of iron and tin, that these 
 substances, under various circumstances, are unstable, the protoxide having 
 a strong attraction for oxygen, and the peroxide, when in contact with 
 organic matters, readily yielding oxygen. 
 
 In one or other of these conditions, these bases combine with the 
 colouring matter. How, then, will the above properties affect the com- 
 pound? The action of the peroxide in contact with organic matters 
 seems to supply an answer to the question, because in all cases in which 
 peroxides give up their oxygen to the organic colouring matter and 
 become protoxides, it would follow that the proper condition of apply- 
 ing the mordant would be the protoxide state. On any other sup- 
 position it would be necessary to prove that when peroxide is applied, 
 the giving up of the oxygen produces a reaction favourable to the 
 resulting colour; but this is seldom if ever the case. The reaction of 
 the peroxide is generally the combination of a part of the oxygen with 
 the hydrogen of the colouring matter, which thus becomes partially 
 decomposed. This will be seen by attempting to dye common black with 
 a persalt instead of a protosalt of iron, or by adding a persalt of iron to a 
 solution of galls or sumach, and allowing them to stand, the colour will be 
 greatly deteriorated. Supposing cloth from sumach put into a solution of 
 persulphate of iron, there will be a decomposition : the persulphate being 
 three acid and two iron, some of the hydrogen of the vegetable colour will 
 produce one proportion of free acid by the reduction of th e per to th e proto 
 sulphate. When peroxide of iron is fixed upon the cloth free of acid, and 
 put into the colouring matter, water is formed by the oxygen of the peroxide 
 and colouring matter. We then have— 
 
 So that one-third of the colouring matter will be destroyed, and a more 
 imperfect dye will result, as will be more fully illustrated when we come to 
 describe the composition of the vegetable dyes. 
 
MORDANTS. 
 
 191 
 
 It is this principle which prevents the use of many oxides of metals 
 that might otherwise be valuable, such as oxide of silver, mercury, &c., 
 which are easily reduced by organic matters. When any of these bases com- 
 bine with vegetable colouring matters as mordants, they are gradually re- 
 duced, and pass into the metallic state, the oxygen taking the hydrogen or the 
 carbon of the colouring matter, and thus the colour fades away. Still this 
 property of giving up oxygen is often of great value in other operations, as 
 in working with substances that require oxidation to give a colour, as in the 
 case of catechu; salts of silver, mercury, &c., would serve the purposes for 
 which copper salts are at present applied to this dye-drug ; whereas persalts 
 of iron cannot be used with this substance for oxygenising purposes, as its 
 protosalt blackens the tannin of the catechu, and affects the production of 
 other shades of colour; but where modified tints are required, iron furnishes 
 the means of obtaining them to a great extent. Thus, by a careful study of 
 the conditions of the mordants, their relations to the colouring matter, the 
 reactions that will take place under all the varied circumstances of appli- 
 cation, and what kind of reaction is required to obtain the results sought, 
 the dyer will find his trade easy, interesting, and pleasant. When the mind 
 guides the hand, labour ceases to be felt either as a curse or degradation. 
 
 In connection with mordants, Dr. Bancroft, in his work on the Philo- 
 sophy of Permanent Colours , arranges all colours in two classes. He says — 
 
 “ To me colouring matters seem to fall naturally under two general 
 classes. The first including those matters which, when put into a state of 
 solution, may be fixed with all the permanency of which they are suscep- 
 tible, and made fully to exhibit their colours in or upon the dyed sub- 
 stance, without the interposition of any earthy or metallic basis. The 
 colours of the first class I shall call subtsantive , as denoting a thing solid, 
 by or depending only on itself ; and colours of the second class I shall call 
 adjective , as implying that their lustre and permanency are acquired by 
 their being adjected upon a suitable basis. 
 
 “ Earthy and metallic substances, when thus interposed, serve not only 
 as a bond of union between the colouring matter and the dyed substance, 
 but they also modify as well as fix the colour : some of them, particularly 
 the oxide of tin and the earth of alum, exalting and giving lustre to most of 
 the colouring matters with which they are united ; whilst others, and espe- 
 cially the oxide of iron, blacken some, and darken almost all such matters, 
 if made to combine with them.” 
 
 This clear definition will remove many erroneous impressions of the 
 meaning of these terms, adjective and substantive. We have often heard an 
 adjective colour defined as one that required to be previously mordanted ; 
 but this definition is ambiguous, and seems to ground the distinction more 
 upon the mode of dyeing than upon the nature of the colour. Thus, by 
 passing a piece of cotton through alum, and then through a solution of 
 logwood, we produce an adjective colour, having been previously mor- 
 danted ; but if the solutions of the alum and lbgwoid be mixed together, 
 and the piece be passed through this mixture, the same colour is produced. 
 
192 
 
 MORDANTS. 
 
 Yet, by the above definition, it would be a substantive colour, not being 
 previously mordanted, and not because the colour produced is neither that 
 of the logwood nor of the alum, but of the compound formed between 
 them. Again, if we pass a piece of cotton through a solution of copperas, 
 and then through lime-water, there is first produced a light-greenish 
 colour, which, by exposure to the air, becomes nankeen or buff ; and not- 
 withstanding its thus taking two operations, equivalent to mordanting and 
 dyeing, the colour produced is substantive, being the pure peroxide of iron 
 fixed within the fibre. Another fallacy we have often heard, namely — 
 identifying substantive and adjective with fast and fugitive. The impro- 
 priety of this application of the term is shewn by simply referring to the 
 two colours, indigo-blue and safflower-pink ; both are eminently substan- 
 tive, yet the one is fast and the other fugitive. 
 
 The property which the fibre possesses of fixing portions of the dye- 
 stuff within its pores will have to be often referred to, as it bears a very 
 important relation to mordants. What are termed astringent substances 
 have a strong action in this way in combining with the fibres of cotton 
 goods. A piece of cotton put into a hot solution of sumach, and remain- 
 ing in it until cool, there is a quantity of the astringent principle, pro- 
 bably gallic or tannic acid, fixed upon the fibre, which no washing will 
 remove. We have seen goods thus treated passed afterwards through all 
 the regular operations of bleaching, and still retaining so much of these 
 substances as was sufficient to impart a black tint on passing them through 
 protosulphate of iron. Hence the astringent matters in many vegetable 
 dyes act a very important part in the dyeing operations. Whether such 
 substances as galls and sumach, which are used only for their astringent 
 principle, may be termed mordants, is a question we need not discuss ; but 
 they are essentially necessary for fixing within the fibre such quantities of 
 the metallic base or mordant as are required to give depth and permanency 
 to the colour; and as these astringent matters produce tints with the 
 bases, they give a wider scope for variety of colour. Thus, if we pass a 
 piece of cotton through a solution of protochloride of tin, and then wash 
 it in water, we will have a great quantity of oxide of tin fixed within the 
 fibre by the operation of washing (page 154) ; and by passing this cloth 
 through a decoction of Brazil-wood, and then raising with a little spirits, 
 there is a fine, though not very permanent, rose-red produced. If we pass 
 the cotton through bichloride of tin, and then wash, there is very little of 
 the oxide of tin fixed ; for the bichloride is not decomposed, as the proto- 
 chloride is, by water. If, then, it be passed through the Brazil-wood in 
 the same manner as the other, a colour of less depth is produced ; but if 
 the cloth be previously steeped in sumach, and be then passed through the 
 tin solution, even the bichloride, the astringent principle of the sumach 
 combines with the tin, and forms an insoluble compound ; and there is 
 thus fixed a great quantity of the metallic base within the fibre, which 
 gives the colour with the Brazil-wood, so that, when immersed into the 
 wood decoction, there is obtained a colour of great depth and permanency. 
 
MORDANTS. 
 
 193 
 
 But the compound formed between the tin and sumach gives a yellow, and 
 thus peculiar tints of the colour are obtained ; instead of having a rose 
 colour, as was obtained without the sumach, a deep rich red, between rose 
 and scarlet, is produced. Thus sumach, galls, &c., are extensively used, in 
 connection with metallic bases, to fix, modify, and impart depth to colours 
 for which these bases are applied. The nature of these astringent sub- 
 stances will be given under the distinctive names of the matters which 
 contain them. 
 
 The strong attraction which animal fabrics, silks and woollens, have 
 for colouring matters is well known, and the dyeing of these fabrics is 
 more simple than that of cotton. The mordants used are often of a class 
 that do not act the part of mordants in cotton. From this cause, means 
 were sought to impart to cotton something of the property of animal 
 tissues. The following are analyses of wools 
 
 Mineral matters, . 
 Suint and fatty matter, 
 Pure wool, . 
 
 Moisture, 
 
 Raw wool. 
 
 6*3 16*8 
 44-3 44-7 
 38-0 28*5 
 11*4 9-0 
 
 Washed wool. 
 
 0-94 1-0 
 
 21-00 27-0 
 72-00 64-8 
 6-06 7-2 
 
 100-0 99-0 ... 100-00 100-0 
 
 The substance termed suint is a singular compound, containing oxalate of 
 lime, silica, chloride of potassium, salts of potash, with certain fatty acids, 
 forming soap. In certain factories the potash from suint is obtained as a 
 product for sale. The fibre of pure wool also contains a good deal of 
 sulphur, not referred to in the above analyses, still sufficient at times to 
 affect light colours where metallic oxides are used, such as lead. Some 
 dyers steep the wool for a long time, and then wash in a weak sour of 
 muriatic acid. Although this does not remove the sulphur from the fibre, 
 it neutralises its action upon metallic oxides. The composition of silk is 
 quite a different affair : — 
 
 Composition of Neapolitan Silk. 
 
 Fibres of silk, 
 
 Yellow. 
 
 53.37 
 
 From Levant. 
 White. 
 
 54-04 
 
 Gelatine, 
 
 20-66 
 
 19-08 
 
 Albumen, 
 
 24-43 
 
 25-47 
 
 Cerin, .... 
 
 1-39 
 
 1-11 
 
 Fat and resin, 
 
 •10 
 
 0-30 
 
 Colouring matter, 
 
 •05 
 
 
 
 
 100-00 
 
 100-00 
 
194 
 
 MORDANTS. 
 
 It was considered that, in all probability, the substances giving the pro- 
 perty to silk to imbibe and fix colours more easily than cotton, were such 
 matters as albumen, &c., which are known to have a strong attraction for 
 colouring matters, and which might be imparted artificially. Upon this 
 subject we extract from the Chemical Gazette , vol. viii., page 384, an 
 excellent article translated from the Journ. de Chem. et de Pharm ., vol. 
 xvii., page 271 : — 
 
 “ When an egg is boiled in a colour-bath, the colour immediately fixes 
 itself to the shell. Egg-shells contain, like bones, an organic tissue and 
 mineral salts. If it is attempted to dye these mineral salts — the phos- 
 phate or carbonate of lime — separately, it fails, and therefore neither 
 of these salts can be regarded as the mordant. If, on the contrary, it is 
 attempted to colour the organic tissue of egg-shells or of bones, this im- 
 mediately becomes dyed ; hence it follows that the organic matter of the 
 bones and egg-shells is the mordant. 
 
 “ Now, in the same manner as mineral mordants have hitherto been 
 employed to fix colouring matters upon cotton, organic mordants may be 
 used; and Broquette has already employed caseine for this purpose. The 
 coating of vegetable fibres with animal substances was first carried out by 
 M. Hausmann, as observed by M. Barreswil, in this article, but is said 
 never to have attained to any importance. The caseine must, of course, be 
 first dissolved, in order that the tissues may be permeated by the solution, 
 but it must then be rendered insoluble in the tissues. Now, it has been 
 shewn by Braconnot that caseine furnishes a soluble compound with 
 ammonia, which is again decomposed by boiling. Broquette, therefore, 
 impregnates the goods with a solution of caseine in ammonia, then heats 
 them to expel the ammonia, upon which the caseine remains in an insoluble 
 state in the tissues. 
 
 “ Cotton goods, after this treatment, are saturated with animal matter, 
 and may now be dyed in the same colour-baths as those used for woollen 
 tissues. 
 
 “ Frequently the dyes are alkaline ; they then dissolve the caseine, 
 instead of being fixed by it. But since Bachelier used as a cement a 
 mixture of lime and caseine, it is known that this mixture hardens and 
 becomes fixed. Broquette therefore employs the caseine sometimes with 
 lime alone, sometimes with ammonia and lime together, and saturates the 
 goods with this caseate of lime, which soon sets in a warm atmosphere, and 
 then resists the alkalies and rinsing with alkaline liquids. 
 
 “ By this treatment the cotton acquires a peculiar stiffness; so that, 
 although its capacity for dyes has become nearly equal to that of wool, it is 
 far behind the latter, owing to want of lustre. But this evil can also be 
 remedied by mixing the mordant with oil. Oil, caseine, and lime form a 
 mordant which fixes the colours with a perfectly remarkable lustre. 
 
 “ When the goods to be dyed consist of wool and cotton, a different 
 plan has to be followed ; the mordant in this case is not adapted for the 
 two materials ; the wool is deprived of its natural lustre, and the cotton 
 
MORDANTS. 
 
 195 
 
 tissues are not sufficiently penetrated. For such goods Broquette employs 
 the mordant before the weaving; it is applied to the cotton in the spinning, 
 when it can afterwards be woven and bleached like wool, without the 
 mordant experiencing any injury. When threads thus prepared are 
 woven, the tissues can be dyed just like woollen stuffs, without further 
 treatment. 
 
 “ By means of the solution of caseate of lime, mineral colours which 
 are insoluble in water can be adapted to the dyeing of stuffs ; they are 
 mixed in a state of very fine powder with the solution. These liquid 
 colours, which can be prepared, for instance, with ultramarine, ochre, &c., 
 can again be removed with water, unless they have been dried; but as soon 
 as they coagulate, they adhere firmly to the tissues enclosing the colouring 
 principle. 
 
 u A further application of the mordant of caseine, oil, and lime, is in 
 the printing of stuffs ; in this case we are not limited merely to mineral 
 colours, which by its aid may be fixed upon the goods, but the numerous 
 vegetable colours may be likewise very well applied, by first converting 
 them into lakes by means of alumina or protoxide of tin, and then using 
 these lakes in the same manner as powdered mineral colours. After being 
 printed, the goods are wrapped in moist linen, and left for about half an 
 hour in the moist vapour in a warm atmosphere. During this time the 
 impressed colour does not dry superficially, but it is absorbed into the 
 interior of the fibres, and is then completely fixed in the subsequent 
 drying. 
 
 “This new method of mordanting has already had considerable in- 
 fluence upon several pigments — for instance, upon archil, which has only 
 been used for dyeing exceptionally ; according to Broquette’s process, 
 some very beautiful colours are obtained from it, modifications of the 
 peculiar colour of the archil by lime. 
 
 “ It will be evident, from what has been above stated, that in this 
 process of dyeing it is requisite to pass the goods through a lime-bath, 
 which will not do for many dyes, as the colours have their tints altered 
 by such treatment. In sueh cases magnesia is to be substituted for the 
 lime. 
 
 “ When goods are printed with the mineral colours or lakes, according 
 to the above process, very full colours are obtained, which, in the case of 
 many patterns, is not desirable. To bring out the shades and half-colours 
 in the full-coloured impressions, the printed goods are placed with their 
 coloured surface upon an absorbing ground, cotton stuff, and the forms 
 pressed on the back. The printed portion pressed upon the absorbing 
 surface is deprived of some of its colour, and numerous patterns can be 
 produced in this manner.” 
 
 The curd of milk, which contains different substances — having properties 
 allied to albumen ; they are insoluble in water, but are rendered soluble 
 by alkaline substances, such as ammonia — has been used in a similar way to 
 the albumen of eggs or blood, and is known in the trade as lactarine. The 
 
196 
 
 RED SPIRITS. 
 
 use, however, of these substances is more for calico-printing than dyeing. 
 In using lactarine for preparing cloth to combine with dyes that have no 
 affinity for the fibre, there is*a great tendency to unevenness in the colour ; 
 as, for example, if the lactarine is dissolved in ammonia, and goods passed 
 through it, and dried hot, the ammonia is volatilised and the lactarine 
 left. Any portion of the piece being a little wetter, as it may be termed, 
 will have more of the lactarine left behind, and form a darker tint on that 
 part. In calico-printing this is different— the soluble lactarine is mixed 
 with the colouring matter and printed on the cloth, and when the ammonia 
 is volatilised the insoluble lactarine and colouring matter remain. 
 
 The preparation of the salts which constitute mordants has been given 
 under the particular element constituting the base of the salt ; but we 
 mentioned that different methods of preparing such salts are practised by 
 different dyers, every one preferring his own method, from some real or 
 supposed peculiarity or advantage it possessed ; although in some cases 
 this difference is difficult to appreciate, both because the acids used are 
 not regularly tested, and also because it is a common custom to take the 
 acids by measure ; so that when a dyer says he prefers 4 to 1, he as often 
 means 4 jugs as 4 lbs. How, nitric acid having a greater specific gravity 
 than hydrochloric acid, 4 measures of this acid to 1 of nitric acid will be 
 quite different to 4 lbs. muriatic acid to 1 lb. nitric acid. The following 
 are a few of the principal mordants used in the dyeing of cotton. The 
 proportions given are by weight : — 
 
 Red Spirits. — These are named from being used in dyeing red by 
 means of Brazil and other red woods. They are sometimes termed nitro- 
 muriate of tin , from being prepared by dissolving tin in a mixture of these 
 acids. Mix together — 
 
 1 lb. Nitric acid, 
 
 3 lbs. Hydrochloric acid. 
 
 Add feathered tin, in small quantities at a time, until the acid ceases to 
 dissolve more ; keep the solution cool, pour off the clear, and preserve in 
 a dark cool place. This is a spirit for a deep heavy red. 
 
 If a red of a bluer or crimson hue be required, then — 
 
 •1 lb. Nitric acid, 
 
 5 lbs. Hydrochloric acid, 
 
 dissolving the tin as above, will give a better quality of mordant. The 
 greater proportion of nitric acid gives brown or depth to the red ; but 
 some sorts of woods contain, more of the yellow or browning principle 
 than others. Attention ought to be paid to this, so as to prepare the 
 spirits suitable to the character of the wood which is to be used as the 
 dye. This difference of tint is occasionally regulated by the quantity of 
 tin dissolved ; hence some dyers give a definite quantity of tin, generally 
 from 2 ounces to 2£ ounces to the pound of mixed acids : this is, indeed, 
 not far from what is generally dissolved when tin is added to saturate the 
 
PLUMB SPIRITS. 
 
 197 
 
 acid. Whichever method is adopted, it is necessary that there should 
 always be a knowledge of the quantity of tin which the spirit contains ; 
 and, moreover, as this is commonly prepared in the open air, the quantity 
 of tin dissolved will depend somewhat on the season of the year, on 
 account of the influence which temperature has on the action of the acid. 
 When red spirits are used with logwood, the influence of large proportions 
 of nitric acid is very apparent, causing the purples, or such colours dyed, 
 to dry brownish — a result, however, which the dyer is often called upon 
 to obtain. The spirit solution in the tub, or beck, in which the yarn is 
 wrought should stand from 2° to Twaddell. 
 
 Barwood Spirits. — These are named from being used as the mordant 
 for dyeing with that wood. They are prepared by taking — 
 
 1 lb. Nitric aeid, 
 
 6 lbs. Hydrochloric acid, 
 
 adding gradually, as dissolved, ounce of tin to the pound of the 
 mixture ; or — 
 
 1 Nitric acid, 
 
 4 Hydrochloric acid, 
 
 2 ob. of tin per pound. 
 
 This spirit should not be used within at least twelve hours after its 
 preparation. There are other variations in its preparation ; they vary 
 generally from 4 to 7 hydrochloric acid to 1 nitric acid. Excess of tin 
 in this mordant is avoided. The same rule as referred to above in respect 
 to the proportion of acids is applicable here, — they regulate the tint more 
 or less. The working solution is 2^° Twaddell ; but the barwood dye 
 requires some experience and attention to manage it well. 
 
 Plumb Spirits, so called from being used with a decoction of logwood 
 to prepare a dye solution of a deep wine or plumb colour, it is sometimes 
 termed a French tub (see page 187, at bottom) — 
 
 Take 7 lbs. Hydrochloric acid, 
 
 1 lb. Nitric acid, 
 
 adding by degrees, as dissolved, 1^ ounces tin to the pound of mixture.; or, 
 
 1 Nitric acid, 
 
 5 Hydrochloric, 
 
 ounce tin to the pound of acid. 
 
 Some prepare this spirit by dissolving the tin in hydrochloric acid alone. 
 In that case the vessel containing the acid should be placed in a hot 
 situation ; it is generally, indeed, placed in another vessel containing 
 boiling water. Plumb spirits are also prepared by dissolving some of 
 the salts of tin in dilute hydrochloric acid. For to 2 lbs. of logwood 
 used, 1 lb. of the spirits is added. 
 
198' 
 
 NITRATE OF IRON. 
 
 Yeleow Spirits, as before mentioned (page 159), are prepared with 
 sulphuric instead of nitric acid, but they are seldom now used. 
 
 The above embraces, with very little modification, almost all the qualities 
 of spirits used for cotton. That termed oxymuriate of tin, when used for 
 woollens and : sillks, is prepared by adding to a solution of the salts of tin 
 in hydrochloric acid, some nitric acid, which causes effervescence, and an 
 escape of red fumes of nitrous oxide, caused by the peroxidising of the 
 tin. The same result is often observed in the preparation of the spirits 
 given above, when the tin is added too rapidly, and heat is developed ; 
 there is then a rapid solution, and fumes of nitrous oxide are given off, 
 producing what the dyers eall firing. Fired spirits, or spirits thus peroxi- 
 dised, give brownish, dull, and unsatisfactory colours on cotton. 
 
 Several qualities of spirits are used for woollen and also for silk, by 
 adding sal-ammoniac, or common salt, to nitric acid, along with the tin — 
 the former most commonly ; by this method a double salt of chloride of tin 
 and ammonia is produced. The proportions of the acid and the sal- 
 ammoniac and tin are varied for different objects ; but spirits prepared 
 in this way are seldom if ever used for cotton. The strength of the acids 
 used is the ordinary commercial aquafortis and muriatic acid. 
 
 Nitrate of Iron is prepared by taking a quantity of common nitric 
 acid (aquafortis), and adding clean iron (generally old hoops with the rust 
 beaten off) as long as the metal will dissolve. The acid acts best when 
 diluted in the proportion of about one part to six of water; and after it 
 has ceased to act upon the iron, all the metal not dissolved ought to be 
 removed, otherwise the nitrate will continue to dissolve more of it, and 
 precipitate oxide of iron, and thereby produce a thick insoluble mass at 
 the bottom (see page 136) : the solution should be clear. Some prefer to 
 add only a small quantity of iron for light shades, but we have never seen 
 any advantage in such a mode of proceeding. The iron and nitric acid 
 ought, however, to be weighed, and have a fixed relation to each other. 
 This solution of iron should be kept in the dark. 
 
 This salt or mordant is manufactured on a large scale and sold in 
 solution in carboys. We have generally found it to be a mixture of 
 nitrate and persulphate of iron. A sample recently tested, bought from 
 a very respectable maker, had a specific gravity of 90° Twad. ; it contained 
 per gallon 36 ounces by weight of sulphuric acid (S0 3 ) and 2 ounces of 
 muriatic acid,, so that either the nitric, acid had been very impure or 
 sulphuric acid had been added, either in the form of acid or as sulphate 
 of iron. The impurities in common aquafortis is more commonly muriatic 
 acid, generally about 2 ounces to the gallon of aquafortis. A curious 
 circumstance in using persalts of iron may be noticed: if a piece of cloth 
 of a mixed fabric of cotton and woollen be put into nitrate of iron, the 
 cotton will be dyed a deep buff colour, while the woollen remains little , 
 affected; but if the same kind of cloth be put into perchloride of iron the 
 reverse takes place, the woollen is dyed while the cotton is but little affected. 
 
 In this way the presence of cotton may be detected in woollen fabrics. 
 
TARTAR AS A MORDANT. 
 
 199 
 
 Acetate of Iron and Alumina. — This mordant is now seldom used ; 
 but it is useful for dyeing a wine colour, &c., with logwood. It is pre- 
 pared by dissolving equal parts of copperas and alum in boiling water, 
 then adding a solution of acetate of lead as long as a precipitate is formed. 
 Allowing this to settle, the clear solution is the double acetate. But a 
 better and cheaper mode of preparing it is to mix black iron liquor and 
 red liquor together, which form the mordant in question. 
 
 Acetate of Alumina, or Pyrolignite of Alumina (see page 121 for an 
 account of its preparation, and the mode of testing it). It is not, however, 
 prepared by the dyer. We may mention, as this mordant is often dried 
 upon the cloth in stoves at a high heat, that care should be taken not to 
 allow two pieces of the cloth to hang too closely together, this prevents 
 a free circulation of air ; the stove ought also to be well ventilated, other- 
 wise the warm vapour of the acetic acid will react upon the mordant in 
 the cloth, and give an unequal dye, and full of dark parts, thus rendering 
 the colour cloudy. 
 
 Black Iron Liquor. — This is pyrolignite of iron, prepared by allowing 
 iron to steep in pyroligneous acid. It is not prepared by the dyer. We 
 have given a method of testing it (page 135). 
 
 Iron and Tin for Royal Blue. — This is- not prepared to stand in 
 reserve, but only when about to be used. The iron solution used for this 
 colour should be well killed , that is, the acid should be well saturated with 
 iron, and produce a solution of a deep dark red. Some dyers add a little 
 muriatic acid to the iron when, it is to be used along with the tin. The 
 crystals of tin should be added to the iron liquor immediately before 
 entering the goods, and the liquor should be well stirred to prevent 
 inequality. 
 
 Acetate of Copper. — This is sometimes prepared in the dye-house in 
 a similar manner to acetate of alumina, viz., by adding a hot solution of 
 sulphate of copper ( 'blue-stone ) to a solution of acetate of lead : the clear 
 liquor is acetate of copper. It is better, however, to purchase it in the 
 crystallised state; this forms a good alterant for logwood blues. It is not 
 much used in cotton dyeing, but useful for woollen. 
 
 Bichromate of potash is used as a mordant for cotton with great 
 success, especially in mixed fabrics of cotton and wool. 
 
 There are a variety of other mordants used in woollen and silk dyeing, 
 but these we do not particularise here, as they will be treated of under 
 recipes; but we proceed to enumerate a few theoretical considerations 
 concerning the action of mordants generally upon silk, cotton, and wool. 
 
 Cream of tartar — bitartrate of potash — is a very feeble mordant 
 alone; still it is universally employed in dyeing woollen fabrics. When 
 used along with alum, sulphate of iron, or chloride of tin, it is a strong 
 
200 
 
 THEORY OF MORDANTS. 
 
 mordant, probably owing to decomposition : the sulphuric acid of the 
 alum and iron, and the chlorine of the tin, may take the potash from 
 the tartar, and the alumina, iron, or tin be converted into a tartrate, and 
 in that state combine more readily with the wool, and be much less 
 destructive to the fabric. Woollen goods seem to require certain thermal 
 and acid conditions of the mordant; and it is known that a portion of the 
 wool dissolves, and an equivalent of the mordant takes its place : this has 
 been especially demonstrated of alum mordants. 
 
 For silk, the alum mordant is always used cold, otherwise the lustre 
 of the silk is destroyed; and alum, having the least quantity of acid, is the 
 best and most effective mordant. This explains why the Roman alum is 
 always preferred. It may also be remarked that silk, in relation to alum, 
 comes closest to cotton. 
 
 We copy the following theory of the action of mordants by M. 
 Dumas : — 
 
 “ Cream of tartar, or bitartrate of potash, constitutes by itself a feeble 
 mordant, but which is very often used in dyeing light woollen stuffs, 
 to which we may wish to give a delicate but brilliant shade. It is also 
 employed in the dyeing of ordinary woollen goods, but here it is associated 
 with alum, sulphate of iron, chloride of tin, &c. Its influence, under these 
 circumstances, consists evidently in determining a double decomposition, 
 from which we have produced a sulphate of potash or chloride of potassium, 
 whilst the tartaric acid combines with the alumina, the peroxide of iron, or 
 the oxide of tin. Now, it is very probable that the colouring matters 
 remove the alumina, the peroxide of iron, or the oxide of tin, more readily 
 from tartaric than from sulphuric acid. Moreover, the presence of free 
 sulphuric acid would certainly prove injurious, as well to the stuff as to 
 the colouring matter, whilst free tartaric acid can exercise no unfavourable 
 action over them. 
 
 “ The operation of subjecting wool to the alum mordant is always 
 effected at the boiling point; the mixture used in this process is a com- 
 pound of alum and of cream of tartar. One of the objects of this addition 
 is to free the bath of the carbonate of lime which the water generally 
 retains in solution, and which, acting on the alum, would determine its 
 partial decomposition by producing an insoluble subsulphate of alumina 
 and potash, and this accumulating on the stuff, and becoming unequally 
 fixed upon its surface, would lead to stains or blotches on passing the 
 material through the dye-bath. But, independently of the above effect, 
 which might be produced by any acid, cream of tartar appears to be 
 capable of effecting a further object, by inducing a double decomposition, 
 which transforms the alum into a tartrate of alumina. However this may 
 be, after one or two hours 1 boiling in the alum-bath, the cloth, which 
 should be constantly agitated so as to cause a more equal application of 
 the mordant, is withdrawn from the copper, and, after thoroughly drain- 
 ing, it should be put aside for two or three days, when we wish to dye it 
 with any full-bodied colour. Experience has proved that this repose after 
 
THEORY OF MORDANTS. 
 
 201 
 
 the use of the mordant greatly favours the union of the latter with the 
 stuff. In applying the tin mordants we also make use of cream of tartar. 
 It is, moreover, an indispensable addition where we desire to fix the salts 
 of iron previously to dyeing in black. 
 
 “ Woollen cloth, on being dipped into a cold aqueous solution of alum, 
 appropriates to itself a part of this salt, but without undergoing any very 
 sensible alteration. MM. Thenard and Hoard have, indeed, proved that 
 cloth, when thus treated by a cold solution of alum, gives up this salt to 
 boiling water, and that, after a few washings performed at the boiling 
 point, it will have parted with the whole of the alum which it had received 
 in the cold bath. When, however, cloth is boiled in a solution of alum, 
 it yields to this liquid a portion of its organic matter, which becomes 
 dissolved; but at the same time it absorbs an equal amount of the 
 alum. 
 
 “We have now merely to shew the action which wool undergoes 
 when brought into contact with alum and cream of tartar at one and the 
 same time. It is very possible that there may be in this case a simul- 
 taneous fixation of alum, as well as of the double tartrate of alumina and 
 potash, and of tartaric acid. The presence of alum in the cloth when 
 taken from the boiling solution is very evident ; that of the tartrate of 
 alumina and potash and of free tartaric acid is only presumable. 
 
 “ Silk, in like manner, unites itself with alum when placed in a cold 
 solution of this salt, and afterwards parts with it to boiling water; it may 
 be reproduced from this liquor by evaporation. The action of silk on 
 acetate of alumina is identical with that of wool. It at first absorbs this 
 salt in its pure form ; then, by desiccation it loses some acetic acid, and 
 retains a mixture of the acetate together with alumina in its free state ; it 
 gives up a further portion of this acetate to boiling water. 
 
 “ Tiie alum mordant is always used cold with silk: if employed hot, it 
 would destroy its lustre. The bath should not contain cream of tartar 
 when it is intended for this material ; on the contrary, we here have 
 recourse to a variety of alum of as neutral a character as possible. 
 
 “ The theory of the action of mordants is connected in the closest 
 manner with that of dyeing. It may, in fact, be viewed under two very 
 different aspects. Sometimes we admit that there exists a true combination 
 between the stuff and the colouring matter — a combination which can only 
 be determined by a veritable affinity between these two bodies, and which 
 will present a condition analogous to that which occurs in all chemical 
 combinations — that is to say, a state of saturation, beyond which the union 
 of these bodies becomes of a very unstable character; at other times, on 
 the contrary, we regard the dyeing of stuffs as produced by a nearly 
 mechanical phenomenon, by virtue of which the colouring matters 
 become imprisoned in the meshes of the organic filaments contained 
 in the material to be dyed. This latter opinion is evidently the better 
 founded. It approximates the theory of dyeing to some analogous 
 phenomena which we find manifested by animal charcoal on coloured 
 
202 
 
 THEORY OF MORDANTS. 
 
 solutions; for, as the animal charcoal seizes upon the colouring matters 
 contained in an aqueous solution, and renders them insoluble by fixing 
 them in a purely mechanical manner within its own pores: so may the 
 wool, the silk, and the cotton, appropriate the colouring matters held in 
 solution, and, by fixing them in their pores, render them more or less 
 insoluble to water. Experience, however, shews that dyeing thus pro- 
 duced is wanting both in intensity and in fixity — two qualities which it 
 derives by the previous application of a mordant. Now, we can readily 
 see that the mordants themselves may become fixed in the tissues by 
 similar causes to those which determine the fixation of the colouring 
 matters by animal charcoal. We know, in fact, that this latter body 
 possesses the property of removing from water not only the colouring 
 matters, but also certain salts. There will, therefore, be no difficulty in 
 imagining that silk, wool, and cotton may, in their character of porous 
 bodies, purely and simply seize upon the alum, and that this salt, when 
 once imprisoned in the meshes of the tissue, may subsequently react 
 upon the colouring matter according as this latter, in its turn, penetrates 
 the interior of these materials. 
 
 “We may then refer the phenomena of absorption, which characterise 
 the fixation of the mordants and the penetration of the colouring principles 
 into the tissues, to the same cause as that which determines the action of 
 animal charcoal on certain soluble salts and colouring matters. But if one 
 of these stuffs be impregnated with alum and then dipped in a bath of 
 soluble colouring matter, it acquires a very deep tint, which appears to 
 be essentially produced by a kind of lac, formed by means of the 
 colouring matter and the base of the mordant. On the other hand, in a 
 great number of cases, the mixture of the above mordant with the dye- 
 bath fails in producing an insoluble precipitate. Thus, when we mix 
 together alum and a decoction of Brazil-wood, no precipitate is formed, 
 and, to obtain a lac from this liquor, we are obliged to add some alkali or 
 alkaline carbonate, such as ammonia ; in a word, we must render the 
 alumina free. While admitting, then, in accordance with the experiments 
 of MM. Thenard and Board, that the stuffs fix the alum in its natural 
 state, we must acknowledge, at the same time, that, by some special 
 action, the tissue subsequently determines the union of the base of the 
 mordant with the colouring matter. This special action is equivalent to 
 that of the alkali. 
 
 “ Now, it is certain that the above-mentioned stuffs possess in a high 
 degree the faculty of seizing upon the insoluble colouring matters when these 
 are presented to them in their nascent state. It is thus that cotton becomes 
 dyed of a rose colour in a liquor which contains carthamic acid in sus- 
 pension, arising from the decomposition of carthamate of soda by an acid. 
 In like manner we find wool acquire a black colour, when placed in a 
 boiling solution of a salt of iron and tannin, by attracting to itself the 
 black precipitate resulting from their admixture. Consequently, although 
 the dyer generally endeavours to produce the insoluble compound, on 
 
THEORY OF MORDANTS. 
 
 203 
 
 which the colouring stuff depends, within the very pores of the tissue, still 
 we may affirm that, in many cases, the cloth or other material, when placed 
 in presence of the nascent precipitate, has the property of seizing upon it, 
 and thus acquiring a shade of greater or less intensity. 
 
 “It is to this property (which is due to some hitherto undetermined 
 cause) that we must undoubtedly refer the reaction which takes place 
 between the alum and the soluble colouring matters, as well as some of 
 those more mysterious phenomena which are manifested in dyeing. How 
 else, indeed, are we to account for the fact that wool so readily takes a 
 scarlet colour, while cotton and silk are unable to fix it? How explain the 
 cause of wool so easily appropriating the black precipitate formed by 
 tannin and the salts of iron, while silk, under the same circumstances, 
 acquires a black colour only by great trouble and expense ? How, in one 
 word, can we understand why certain colours should fix themselves better 
 on certain materials than on others, unless it be by virtue of some special 
 action, wrongly designated by the name of affinity, but which does not the 
 less constitute a force, or rather a consequence of diverse forces of which 
 we must take full account during the operations of dyeing? To con- 
 found, in fact, a chemical affinity properly so called, such as is evidenced 
 in ordinary chemical combinations when produced in definite proportions, 
 with the phenomena of dyeing, is certainly to mix together two very 
 distinct ideas. The union of silk with Prussian blue, or of wool with 
 indigo, is quite a different thing to the combination of sulphur with lead. 
 But to consider the tissue as a simple filter, capable of retaining in its pores 
 certain precipitates, and of receiving from them peculiar colours, is to go 
 equally far in an opposite direction; nor would this supposition at all 
 explain the mode in which the coloured lac is formed in most of the 
 operations of dyeing, operations which are effected by an aluminous 
 salt and a colouring bath, altogether incapable of producing any lac, 
 except by the addition of an alkali for the purpose of setting the alumina 
 at liberty, or of a stuff which has the power of taking up the lac, as quickly 
 as it is formed. 
 
 “ Among the reasons which induce us to regard the insoluble colouring 
 matters and the stuffs as capable of uniting together by virtue of some 
 special force, we must mention the facts elicited by the recent experi- 
 ments of M. Chevreul, who has found that the stuffs and colours, when 
 once united, form products which are endowed with properties differing, 
 according to the nature of the stuff, in the same given colour. The pro- 
 perties of the dyeing matter are, then, greatly modified by the peculiar 
 action of the tissue on the dye. Numerous examples place the truth of 
 this assertion beyond all question. It becomes, therefore, perfectly clear 
 that it is only by an attentive and systematic study of the specific pro- 
 perties of the stuffs, in their relation to the various dyeing matters which 
 we may desire to fix upon them, that we can hope to direct the future 
 progress of the art of dyeing.” 
 
 The late Walter Crum of Thornliebank made the fixing of colours 
 
204 
 
 THEORY OF MORDANTS. 
 
 upon fibre a special study for several years, and gave as the result of this 
 inquiry, that there was no real chemical union between the fibre and 
 colour; and on this matter we will convey his ideas better by a few 
 extracts from his papers. 
 
 “ Cotton in the bleached state may be considered as pure woody 
 fibre or cellulose C 12 H 10 O 10 . It is one of the most inert of the vegetable 
 bodies. In the textile fabric it is capable of having incorporated with it, 
 in all proportions, a multitude of different substances, without changing 
 its own or their physical or chemical characters, except by holding them 
 against mechanical effort to wash away or otherwise to separate them, but 
 yielding them up to their proper solvents as readily as they could be taken 
 from a surface of glass. 
 
 “The attraction which is attributed to porosity or capillary we know 
 to be an attraction of surface ; but it is one in which, in consequence of its 
 structure, the absorbing body has its power of attraction for that which it 
 imbibes immensely increased. The term capillary gives but a faint idea of 
 the disproportion between the extent of surface of the cell which constitutes 
 a pore in the woody fibre and the almost mathematical line or point of 
 matter which the cell is capable of containing. 
 
 “ The power which charcoal possesses of attracting to its surfaces 
 certain solid bodies which are dissolved in water is equally well known. 
 Bone charcoal removes the colouring matter from the brown solution of 
 tartaric acid, and from syrup in the refining *of sugar. It precipitates lime 
 from lime-water, and metallic oxides from their solution in ammonia or 
 caustic potash ; but no chemical union has ever been supposed to exist 
 between the charcoal and these matters. It is well known to be chemi- 
 cally indifferent to all bodies.” 
 
 Substances applied to cotton as dyes, or for the purpose of attracting 
 dyes, become fixed in the cotton fibre in two different ways. 
 
 1. They are attracted and precipitated from their solutions by the 
 pores of the cotton; or, 
 
 2. They enter these pores in combination with an acid or other 
 solvent, and in a state of solution, and are there fixed, not by an effort 
 of porosity, but by the subsequent removal of their solvent, or by other 
 means which render them insoluble in water. 
 
 As an example of the first or attraction of porosity, Mr. Crum 
 instances the blue dyed by the ordinary blue vat, which will be described 
 in its place. Of the second class, where the mordant or dye has entered 
 and become fixed within the fibre independently of attraction, he gives as 
 examples madder colours with mordants of iron or alumina, and remarks 
 as follows : — 
 
 “ 1. That the pores, whether larger or smaller, receive the solution of 
 iron by ordinary hydrostatic capillary attraction. 
 
 “ 2. That while within these cavities or vessels, whatever be their 
 form, the salt is peroxidised and decomposed ; and, 
 
 “ 3. That the result of the decomposition — an insoluble oxide is left 
 
THEORY OF MORDANTS. 
 
 205 
 
 there by the volatile acid, which by the solvent power had placed it in 
 that position. 
 
 “ Having formed the idea that no portion of the dye but that which 
 is held most firmly within the cotton-fibre could bear the severe soaping 
 operations to which this class of prints is subjected, I formerly described 
 a piece of dyed cotton, as consisting of a set of colourless bags, containing 
 coloured substances, and in so far resembling the cells of natural flowers ; 
 but the statement was incomplete, and the proof rested to some extent 
 upon theoretical considerations, until the opportunity occurred of observing 
 the effects of the same process upon dead cotton 
 
 What was technically known as dead cotton was a kind of cotton that 
 would not take the dye, and what it did take it could not retain, or with- 
 stand the after- operations it was subjected to. By careful microscopic 
 examination, this cotton was found to be unripe cotton ; and Mr. Crum 
 says of them : — 
 
 “ These fibres are readily distinguished from those of ordinary cotton, 
 by their perfect flatness, not having the vestige of a cavity even at the 
 sides, and by their uniform as well as great transparency. They are 
 broader than the usual fibre, and they shew numerous folds both longi- 
 tudinal and transverse.” 
 
 Referring to the ripe and unripe fibre of cotton, after careful investi- 
 gation, Mr. Crum adds — 
 
 “ Here, then, are two specimens of cellulose, having the same chemical 
 composition, and subjected to the same process of dyeing — one of them 
 which is formed by deposition in a manner to expose the greatest amount 
 of surface, and enclose the greatest number of minute cavities, having the 
 power of decomposing certain solutions and entrapping mordants, while 
 the other, a hard compact polished membrane, is without appreciable 
 action upon mordants or dyes.” 
 
 And thus Mr. Crum, by a most exhaustive series of microscopic 
 observations on all the varieties of cotton fibre — half-ripe, unripe, and 
 full-grown, dyed and undyed— has, we think, fully proven that dyes, 
 whether substantive or adjective, do not combine chemically with the 
 fibre, but are imbibed into the cavities and pores by what is termed 
 capillary attraction, which has a power of decomposing certain substances 
 and retaining them within these cells or cavities. A conclusion to which, 
 from a practical point of view, we unhesitatingly subscribe; at the same 
 time, we observe that the substantive colours — those colours that are 
 imbibed into the cavities in a solid form without mordants, such as 
 indigo blue and safflower reds — can be washed out by repeated washings 
 in clean water, more readily than most of the adjective colours, especially 
 those fixed by astringent substances. We have washed a deep indigo blue 
 dyed in the blue vat and rose-pink dyed by safflower to nearly whiteness, 
 while the same amount of washing had no effect upon Turkey-red. 
 
VEGETABLE MATTERS USED IN DYEING. 
 
 Introductory Remarks. 
 
 In entering upon this division of our subject, we may mention that it is 
 not our intention to go through anything like a systematic course of 
 vegetable chemistry, but to confine ourselves to those vegetable substances 
 which, are used in dyeing, giving their composition and reactions with 
 bases and other matters used in the dye-house. We may, however, give 
 a general outline of the nature of vegetable bodies, beginning with the 
 consideration of the chemical changes which are supposed to take place 
 in Nature, under the influence of light, giving rise to the various colours 
 presented to us in the vegetable kingdom, which will probably aid us 
 in describing the artificial means of imitating Nature in these colours, 
 although as yet there is comparatively little known concerning the nature 
 of these changes. For a long time chemists considered iron to be the 
 colouring principle of all animals and vegetables, being almost universally 
 diffused, and capable of assuming a variety of colours when in combination 
 with other substances ; but it was afterwards demonstrated that the iron 
 present in any vegetable, even in those where it existed most abundantly, 
 was altogether inadequate to produce the splendid colours which vegetable 
 substances assumed. Several other hypotheses were proposed to account for 
 the colours of vegetables; but these hypotheses, not being founded upon 
 inquiry and proof, died at their birth. Within these thirty years a truer 
 method of ascertaining the nature and cause of vegetable colours has been 
 adopted — that is, by the ultimate analysis of vegetable substances in all 
 their stages of existence ; and since then, a number of important facts have 
 been made known respecting this interesting subject, and new ones are daily 
 being added; and many of these discoveries have been made available to 
 the practical man. 
 
 The principal elements of vegetable substances are oxygen, hydrogen, 
 carbon, and nitrogen: the last exists in such a minute quantity, that in 
 many cases it is scarcely appreciable; but according to the opinion of 
 the late Professor Liebig, who stood at the head of this department of 
 chemistry, it is never absent. It is to be remarked, however, that none 
 of the colouring matters of the dye-woods contain nitrogen. There is also 
 a variety of earthy substances in vegetables, such as lime, iron, magnesia, 
 soda, potash, &c., which seem indispensable to the existence of plants ; 
 but they differ in proportion according to the nature of the plant and the 
 soil on which it grows. The three elements, oxygen, hydrogen, and 
 carbon enter very abundantly into the composition of vegetables, form- 
 
VEGETABLE MATTERS. 
 
 207 
 
 ing from 95 to 99 per cent.; but it must not be supposed from this that 
 all vegetables are alike in their chemical properties; they may be, and 
 are more varied than the mineral kingdom, considering the few elements 
 which compose them, and are beautifully illustrative of the law of definite 
 compounds (page 18). The following table, shewing the composition of a 
 
 few substances which constitute 
 serve to illustrate this point : — 
 
 the great mass 
 
 of all vegetables, will 
 
 Gum, .... 
 
 Carbon. 
 
 Oxygen. 
 
 Hydrogen. 
 
 . 12 
 
 11 
 
 22 
 
 Starch, 
 
 . 12 
 
 10 
 
 20 
 
 Sugar, .... 
 
 . 12 
 
 11 
 
 22 
 
 It will be observed from the table how little change is necessary to 
 produce an entirely different compound. It will also be observed, that 
 gum and sugar are the same in composition, which at first sight appears 
 to contradict the law of definite compounds ; but in analysing substances 
 such as are named in the table, they are reduced to their elements, and 
 although we obtain the same weight of elements, we have no positive 
 information how these elements may have been united together in the 
 plant. All those bodies which differ in properties, and at the same time 
 give the same number and weight of elements, are termed isomeric , 
 signifying equal parts. The discovery of bodies having the same 
 number of elements, and differing in their chemical properties, has 
 excited much interest among chemists, and has led to much careful 
 study and investigation, and most important results — the difference 
 is now believed to be in the numerical arrangement of the elements. 
 As, for example, hydrogen and carbon will combine in the proportion 
 of two and two, four and four, and eight and eight, forming three 
 substances, differing considerably in chemical properties, although the 
 elements are combined in the same relation; but interesting as this 
 subject is, we cannot in the meantime enter into any lengthened details 
 it shews us, however, the extensive means employed by Nature for 
 giving us a variety of substances from a few elements. Another point 
 to be observed from the above table is, that the oxygen and hydrogen in 
 each of these compounds are in the same proportion, or in that rela- 
 tive proportion in which they unite ‘to form water. Now, it may be 
 stated as a general rule, that when oxygen and hydrogen are united to 
 carbon in the proportion in which they form water, the resulting com- 
 pounds are of a saccharine or mucilaginous character ; and when vegetable 
 compounds have hydrogen united to carbon without oxygen, or when 
 there is less of that element than would be required to convert the 
 hydrogen present into water, the resulting compounds are generally oily, 
 resinous, or alcoholic. A table of the composition of a few of these sub- 
 stances will illustrate this : — 
 
208 
 
 VEGETABLE MATTERS. 
 
 Oil of turpentine, 
 
 Carbon. 
 
 10 
 
 Hydrogen. 
 
 16 
 
 Oxygen. 
 
 0 
 
 Oil of potatoes, . 
 
 5 
 
 12 
 
 1 
 
 Oil of cloves, 
 
 23 
 
 28 
 
 5 
 
 Resin of gamboge, 
 
 20 
 
 28 
 
 5 
 
 Caoutchouc, 
 
 4 
 
 8 
 
 0 
 
 Beeswax, . 
 
 37 
 
 78 
 
 2 
 
 Pyroxilic spirit, . 
 
 2 
 
 8 
 
 2 
 
 Alcohol, 
 
 2 
 
 6 
 
 1 
 
 When the proportion of oxygen united to carbon is in greater quantity 
 than the hydrogen, or when no hydrogen is present, the resulting com- 
 pounds have generally an acid character: green fruits are in this state, 
 which gives them their sour taste, and makes them deleterious to health, 
 either by giving too much acid to the stomach, or the acid being of a 
 directly poisonous nature; but as the fruit ripens, it takes in or assimilates 
 more hydrogen, and the acid, or at least part of the acid, is converted into 
 a saccharine compound. The following table will shew the composition 
 of a few of the most common acids found in vegetables, as given in Dr. 
 Thomson’s Vegetable Chemistry , doubling the hydrogen : — 
 
 Acetic acid (vinegar), . 
 
 Carbon. 
 
 4 
 
 Oxygen. 
 
 3 
 
 Hydrogen. 
 
 6 
 
 Tartaric acid, 
 
 4 
 
 5 
 
 4 
 
 Citric acid (lemon juice), . 
 
 4 
 
 4 
 
 4 
 
 Gallic acid, .... 
 
 7 
 
 5 
 
 6 
 
 Tannic acid, 
 
 . 18 
 
 12 
 
 16 
 
 There are also a number of alkalies, alkaloids or bases, formed in plants, 
 which unite with the acids, constituting a very important feature in the 
 study of vegetable chemistry, but which we will not in the meantime 
 enter upon further than to state that they almost all contain nitrogen as an 
 ingredient. 
 
 Besides analyses giving the quantities and proportions of each element, 
 as shewn in the above tables, chemists have been led into the necessity 
 of classifying them into groups, having certain properties and composi- 
 tions. Thus in what is termed the polybasic or many basic acids, which 
 are diffused through the vegetable kingdom, such as some of those already 
 named, they are laid down as follows, according to new formulae : — 
 
 Malic acid, 
 Tartaric acid, . 
 Citric acid, 
 Meconic acid, . 
 Gallo -tannic acid, 
 Gallic acid, 
 
 h 2 c 4 h 4 o 3 . 
 
 h 2 c 4 h 4 0 6 . 
 
 hc 6 h 5 o 7 h 2 o. 
 
 H 3 C 7 H0 7 3 H 2 0. 
 
 h 2 c 27 h 20 o 17 . 
 
 h 3 c 7 h 3 o 5 h 2 o. 
 
 There are ample reasons for adopting such formulae by which the 
 
GREEN COLOUR OF VEGETABLES. 
 
 209 
 
 relations of one compound to another are more easily defined. The reader 
 is referred to systematic works on organic chemistry for the full details and 
 reasons for this grouping. 
 
 In our remarks upon light (page 9), we mentioned that colours 
 depend wholly upon the reflection and absorption of light, by the ap- 
 parently coloured substance ; but it was also mentioned, that this result 
 depends upon the chemical constitution of the particular substance ; hence 
 the inquiry into the cause of vegetable colours becomes a chemical one; and 
 from the chemical laws above described, these coloured substances must have 
 a definite constitution; and when any change of colour takes place, there 
 must also be a change of constitution or re-arrangement of its elements. 
 In prosecuting this inquiry, or rather, in collecting the inquiries of the 
 most eminent chemists upon this subject, we shall begin with the para- 
 mount colour of the vegetable kingdom, namely, green. 
 
 Green is well known to be a compound colour, produced by yellow 
 and blue, and is always produced upon cloth by dyeing it first the one 
 colour, and then the other. It is not always the yellow that is dyed first, 
 according to the description in chemical books; but sometimes the blue, 
 according to the nature of the dyeing agent. This will be explained in 
 its proper place. Speaking of vegetable green, Berthollet says, “ The 
 green of plants is undoubtedly produced by a homogeneous substance, 
 in the same way as the greater number of hues which exist in Nature. 
 This colour owes, then, its origin sometimes to simple rays, and some- 
 times to a union of different rays ; and some other colours are in the 
 same predicament. Were the green of plants due to two substances, one 
 of which is yellow and the other blue, it would be extraordinary if we 
 could not separate them, or at least change their proportions by some 
 solvent.” This idea of Berthollet, that the green of plants is a distinct 
 substance existing in the plant, has since been verified. It is obtained 
 by bruising green leaves into a pulp with water, pressing out all the liquid, 
 and boiling the dry pulp in alcohol: when the alcohol is evaporated, there 
 remains a deep green matter, which, by digesting in water, is dissolved, 
 and freed from a little brown colouring matter with which it is mixed. 
 This substance has been named chlorophyl. Later, however, Fremy has 
 ascertained that chlorophyl is composed of a yellow and blue substance, 
 which can be detected; and the fading of leaves is the destruction of the 
 blue. The formation of chlorophyl seems to depend entirely upon the 
 action of the solar rays. “ It is known that the function of the leaves, 
 and other green parts of plants, is to absorb carbonic acid, and with the 
 aid of light and moisture, to appropriate its carbon. These processes are 
 continually in operation: they commence with the formation of the leaves, 
 and do not cease with their perfect development.” But when light is 
 absent, or during the night, the decomposition of carbonic acid does not 
 proceed : it is evident then that a plant kept always excluded from the 
 light must have a difference in its composition. “ No one can have failed 
 to observe the difference between vegetables thriving in the full enjoyment 
 
 o 
 
210 
 
 GREEN COLOUR OF VEGETABLES. 
 
 of light and those which grow in obscure situations, or which are entirely 
 deprived of its agency: the former are of brilliant tints, the latter dingy 
 and white. Numerous familiar instances might be cited, especially among 
 our esculent vegetables : the shoots of a potato produced in a dark cellar 
 are white, straggling, and differently formed from those which the plant 
 exhibits under its usual circumstances of growth. Celery is cultivated for 
 the table by carefully excluding the influence of light upon its stem : this 
 is effected by heaping the soil upon it, so as entirely to screen it from the 
 solar rays ; but if suffered to grow in the ordinary way, it soon alters its 
 aspect, throws out abundant shoots and leaves, and, instead of remaining 
 white and of little taste, acquires a deep-green colour and a peculiarly bitter 
 and nauseous flavour. The heart of the common cabbage is another 
 illustration, and the rosy-coloured aspect of the sides of fruit is referable 
 to the same cause. Changes yet more remarkable have been discovered 
 in plants vegetating entirely without exposure to light. In visiting a coal- 
 pit, Professor Robinson found a plant with a large white foliage, the form 
 and appearance of which were quite new to him : it was left at the mouth 
 of the pit, when the subterranean leaves died away, and common tansy 
 sprung from the roots.” 
 
 Some very curious and interesting results have been obtained by Mr. 
 Hunt and others, respecting the effects of the different rays of light upon 
 vegetable substances, all going to prove the great influence exerted by that 
 agent over the vegetable kingdom, and that to it we are indebted for the 
 beauty of our fields and gardens. 
 
 The green colour of vegetables, as stated, is owing to a peculiar 
 approximate element existing in the vegetable, not invariably nor alto- 
 gether essential to the plant, but depending upon circumstances — these 
 circumstances being at the same time the best for the health and existence 
 of the plant. This colour differs from the other colours of vegetables in 
 the time of its appearing. Flowers of plants do not appear till the plant 
 has reached a certain state of maturity ; but whenever a plant rises above 
 the soil, it immediately begins to assume the green hue, and this hue is 
 continued till the object of the leaves is completed. When a chemical 
 change takes place , the green passes away, and another colour, reddish- 
 yellow, takes its place. These changes are effected in different degrees, 
 and in different lengths of time, just according as the leaves have the 
 property of absorbing oxygen gas. Those leaves which continue longest 
 green absorb oxygen slowest. The leaves of the holly will only absorb a 
 small fraction- of oxygen, in the same time that the leaves of the poplar 
 and beech will absorb eight or nine times their bulk. These last are 
 remarkable for the rapidity and ease with which the colour of their leaves 
 change. That eaves do absorb oxygen gas when they change colour in 
 autumn, and that it is owing to the absorption of this gas, may be verified 
 by placing some green leaves of the poplar, the beech, and the holly under 
 the receiver of an air-pump, and drying them thoroughly, keeping them 
 excluded from light: when taken out, wet them with water, and place 
 
COLOUR OF FLOWERS. 
 
 211 
 
 them immediately under a glass globe full of oxygen gas, when they will 
 change colour; and it will be found that the change of colour is just in 
 proportion to the quantity of oxygen each absorbs. The consequence of 
 this absorption is the formation of an acid, in accordance with the law 
 mentioned before. This acid changes the chlorophyl, or green principle, 
 from green to yellow, and then to a reddish hue. If we treat green leaves 
 with an acid, the same changes of colour take place, and if we macerate a 
 red leaf in potash it becomes green. 
 
 The green of leaves and the colours of flowers are common to all 
 vegetable substances under the influence of light ; but there are a number of 
 colouring substances in vegetables which are peculiar to certain orders, and 
 which exist as proximate elements sometimes in the leaves, in the woody 
 part, in the juice, in the bark, in the flower, in the seeds, and in the roots. 
 Several of these have been made subservient to our use in the art of 
 dyeing, and will be noticed separately. 
 
 The various and beautiful colours of flowers are produced by a some- 
 what different process from that of the green of the leaves, in so far as they 
 do not appear until the plant has attained a certain state of maturity. 
 “ The leaves of the plant being fully developed, they take in more nourish- 
 ment from the atmosphere than what is necessary for the existence of the 
 plant. This extra nourishment takes a new direction, a peculiar transfor- 
 mation takes place, new compounds are formed, which furnish constituents 
 of the blossoms, fruit, and seed.” 
 
 Some of these reactions upon vegetables caused by sunlight, such as 
 the gradual change of leaves from green to yellow seen in the autumn, by 
 the decomposition of the chlorophyl, we look on with little surprise, and 
 so do we also in the case of some flowers, such as the rose, where the 
 calyx opens up and allows the light to fall upon the flower, producing the 
 colour white the calyx remains unchanged ; but when we look at such 
 flowers as the tulip, the calyx is also green, but by sunlight it becomes 
 the flower. The green gradually changes into every variety of hue. If the 
 green petal or calyx of the tulip be chlorophyl, it is decomposed in a 
 different way from what it is in leaves, being converted into a great many 
 compounds, in some cases one colour gradually passes into another, and in 
 others they have marked lines of distinction. If each colour has a different 
 composition, it widens our view respecting the wonderful variety of bodies 
 that may be formed out of a very few elements, and gives hope to the 
 photographer of yet fixing the colours upon his picture. 
 
 Many attempts have been made to transfer the colouring matters of 
 flowers to cloth, but without success. In general they are so fugitive as 
 to change the moment they are brought into contact with the atmosphere, 
 and such of them as can be extracted have no affinity for the cloth. If a 
 third substance be used to give this affinity, it destroys the original colour 
 of the vegetable. 
 
 It is very probable that all the colours of flowers depend upon only a 
 few proximate elements formed in the vegetable, in the manner already 
 
212 
 
 VEGETABLES USED IN DYEING. 
 
 described, and that their various hues are the consequence of the presence 
 of acids affecting more or less this colouring substance. This is the most 
 probable hypothesis that has been framed, and with which we must rest 
 satisfied till more accurate experiments verify its truth, or give us a better. 
 The following summary of experiments will give some idea of the views 
 held upon this subject : — u The expressed juice of most red flowers is blue ; 
 hence it is probable that the colouring matter in the flower is reddened by 
 an acid, which makes its escape when the juice is exposed to the air. The 
 violet is well known to be coloured by a blue matter, which acids change 
 to red ; and alkalies and their carbonates first to green and then to yellow. 
 The colouring matter of the violet exists in the petals of red clover, the 
 red tips of the common daisy of the field, of the blue hyacinth, the holly- 
 hock, lavender, in the inner leaves of the artichoke and numerous other 
 flowers. The same substance made red by an acid colours the skin of 
 several plums ; probably, also, gives the red colour to the petals of the 
 scarlet geranium, and of the pomegranate tree. The leaves of the red 
 cabbage, and the rind of the long radish, are also coloured by this prin- 
 ciple. It is remarkable that these, on being merely bruised, become blue, 
 and give a blue infusion with water. It is probable that the reddening 
 acid in these cases is the carbonic, which, on the rupture of the vessel 
 which encloses it (being a gas), escapes into the atmosphere. If the 
 petals of the red rose be triturated with a little water and chalk, a blue 
 liquid is obtained. Alkalies render this blue liquid green, and acids 
 restore its red colour.” 
 
 We need hardly mention that the influence of light in producing 
 colours, and changing them when produced, is regulated to a great extent 
 by the vitality of the plant; so that the effects vary in intensity according 
 to the season of the year. When leaves or flowers are taken from a plant, 
 they are both very soon affected by light ; but it has been observed by 
 Sir John Herschel, that flowers plucked at an early period, as when 
 newly formed, are much more sensitive to light than at a later period 
 of flowering, shewing that flowers have a period of maturity; and if 
 pulled at that time,, the colouring compound is much more stable, and 
 resists the action of light much more powerfully than when pulled before 
 they are matured. This law of development and maturity is universal, 
 and may be the cause of many of the varieties — the superiority or inferiority 
 of many vegetable dyes even of the same kind. 
 
 The vegetable substances used in dyeing may be divided into two 
 classes : first, those which are used not on account of their possessing 
 colouring properties, but because they possess matters that have a strong 
 attraction for the fibre, which they fill, and also form insoluble compounds 
 with the bases, and so enabling them to act the part of mordants "to the 
 substances which are afterwards to be applied; and second, those sub- 
 stances that are applied or used for the colouring matter they contain. 
 
 The substances comprised in the first class of these are termed 
 astringents, from their producing a roughening or corrugating effect upon 
 
GALLS. 
 
 213 
 
 the mouth when tasted. All the vegetables that produce these effects are 
 tound to contain certain acids, to which this property of astringency is 
 referable ; and the presence of these acids gives them their value in the 
 dye-house. These acids, as we have already stated, are gallic acid and 
 tannic acid or tannin. 
 
 It has been found, from the extensive researches of Dr. Stenhouse on 
 the vegetables containing these substances, that the tannin exists in them 
 m a great variety of modified forms, or rather that they give certain modi- 
 fied reactions with chemical agents, the cause of which, from several 
 analyses, has been defined to be compounds of different proportions of 
 elements which have been formulated, thus 
 
 Moritannic acid, 
 Quinotannic acid, 
 
 Ci 8 H 16 Oi 0 . 
 
 C28H38O17. 
 
 For our purposes we will divide these substances thus acted upon 
 into two — r 
 
 1. Those which give a black precipitate with the salts of iron— for a 
 proper type of which may be cited galls and sumach ; and, 
 
 . 2 * Those which give a dark-olive precipitate with iron— the type of 
 which is catechu. The latter is much more stable in its composition, and 
 less liable to change by standing. 
 
 Galls. 
 
 Upon certain species of oak there grow excrescences which originate 
 m punctures, made by a peculiar insect, for the purpose of depositing her 
 eggs. A kind of juice exudes from this puncture, and gradually forms 
 round these ova hard round bodies, varying in size from one-fourth of an 
 inch to an inch m diameter. These substances, from their resemblance to 
 nuts, and from their bitter taste, are called gall-nuts. The excrescences 
 are produced by the cynips (gall- wasp), upon the tender shoots of the 
 Quercus mfectoria, a species of oak which is common in Asia Minor. When 
 the maggot is hatched, it eats its way out of the nidus. The best galls are 
 those brought from Aleppo and Smyrna. From repeated experiments of 
 many excellent, chemists upon this substance, it is considered to contain 
 two peculiar principles. One of these, a crystallisable matter, is obtained 
 rom a macerated solution of galls, after standing in the air for a longtime. 
 This, from its possessing many acid properties, is termed gallic acid. The 
 other is that substance which combines with skins during the process of 
 tanning, changing them into leather, and is termed tannin, or, from its 
 having some acid properties, tannic acid. 
 
 The best galls, according to Sir H. Davy, contain 26 per cent, tannin 
 and 6-2 of gallic acid, but from the circumstance of these two compounds 
 being generally found together in the same vegetable, and in variable pro- 
 
214 
 
 GALLS. 
 
 portions, it was thought probable that the one produced the other. This 
 supposition was verified to a great extent by M. Pelouze, particularly as 
 respects the tannin of galls. 
 
 O A method of extracting tannin from galls is as 
 follows : — To a vessel such as that represented in the annexed 
 figure is fitted, by means of a cork g, a funnel-shaped tube, 
 and the neck c is kept corked air-tight during the process. 
 At the bottom of the tube is placed a little clean cotton, as 
 shewn at f. Above the cotton is placed a quantity of nut- 
 galls in fine powder, as shewn at e. Over this is poured a 
 quantity of common sulphuric ether, sufficient to fill the rest 
 of the tube, as seen at d. A cork is then fitted tightly to the 
 opening at the top of the tube, and the whole set aside. 
 Next day, two layers of liquor are found in the vessel a, one 
 very light and limpid, occupying the upper part, the other 
 having a light-amber colour, and the consistence of a syrup, 
 occupying the lower part. These liquids are put into a 
 pipette, upon which the finger is kept, and after remaining 
 at rest for a few minutes till they separate, the heavy 
 liquid is allowed to fall out into a capsule, and the light liquid retained, 
 so that it may be distilled for the sake of recovering the ether. The 
 dense liquid which is in the capsule is next to be washed two or three 
 times with sulphuric ether, and afterwards dried by a very gentle heat ; 
 the matter left has a spongy appearance, is very brilliant, and generally of 
 a yellow tint. This is tannin in a state of purity. By this process, from 
 35 to 40 per cent, can be extracted from nutgalls. 
 
 M. Pelouze found that if a solution of tannin be kept closely corked 
 from the atmosphere no change takes place; but if left in contact with 
 oxygen, the tannin undergoes a change, and gallic acid is formed. Hence 
 he concludes that gallic acid does not exist except in very minute quantity 
 in vegetables, and that the error of supposing that these two acids existed 
 together in galls, arose from the common method adopted to procure 
 gallic acid, which was by allowing the macerated vegetable matter in water 
 to stand in contact with the air till the gallic acid crystallised from the 
 solution, this being nothing more than a process for converting tannin into 
 gallic acid by the absorption of oxygen. 
 
 This discovery is of great importance to the dyer, as it points out the 
 evil of allowing liquids which contain tannin to stand exposed to the air for 
 any length of time ; for although gallic acid and tannin act in a somewhat 
 similar manner with metallic oxides, yet the gallates are much more fugitive 
 than the tannates. For example, if we precipitate tannic acid and gallic 
 acid by a persulphate of iron, they are both dark blue, bordering on black; 
 excepting a slight change of shade, the tannate remains permanent ; but if 
 the gallate be allowed to stand a few hours, it is dissolved in the supernatant 
 liquid, and becomes almost colourless ; the sulphuric acid resumes its 
 attraction for the iron, and crystallises as a protosulphate (copperas), and 
 
GALLS. 
 
 215 
 
 the gallic acid is partly decomposed and partly crystallised. These changes 
 take place in a few minutes, if the liquor containing the precipitate be boiled. 
 Now, if galls, or what is now more commonly used instead, sumach, be 
 allowed to stand till fermentation takes place, which does very soon, a 
 great portion of the tannin is converted into gallic acid ; and although the 
 cloth dyed in sumach that is thus altered should be, as some dyers affirm, 
 equally dark, the colour will not be equally fast ; but from personal experi- 
 ence, we can say that it is neither equally dark nor equally beautiful. It 
 cannot be so dark, for gallic acid being much more insoluble than tannin 
 falls to the bottom whenever it is formed, and consequently leaves the 
 supernatant liquid much weaker in its dyeing properties. 
 
 More recent discoveries have shewn that tannin is convertible into 
 gallic acid by other and much more rapid means than being left to absorb 
 oxygen: these are by the common processes of inducing fermentation. It 
 is well known that fermentation is simply a derangement of the elements of 
 certain complex compounds, and the re-arrangement of these elements in 
 different positions and proportions, giving rise to new and altogether 
 different compounds of a more simple nature. The primary compounds have 
 been formed under the influence of the vital principle; but whenever this 
 is withdrawn, the attraction of their elements seems too weak to enable 
 them to resist any marked change of circumstances. Even a slight elevation 
 of temperature is sufficient to overpower their affinities and induce change. 
 Or if they are brought into contact with a body which is in the act of derange- 
 ment, such as yeast, that body excites the same derangement in them, and 
 the equilibrium being disturbed, the elements are left to arrange themselves 
 according to their different attractions. If, for example, we dissolve a little 
 sugar of grapes, which is composed of 12 carbon, 24 hydrogen, and 12 
 oxygen, in a little water, and raise the solution to a temperature of about 
 80°. Fah. ; and if to this we add a little yeast, which is a substance whose 
 atoms are in the act of transposition, the yeast does not combine chemically 
 with the sugar, but it communicates to it by contact the action of trans- 
 position, and thereby deranges the arrangement which the atoms had 
 assumed to form sugar; and the atomic elements, being thus set at liberty, 
 begin to arrange themselves differently: every six equivalents of the 
 hydrogen combine with two of the carbon and one of the oxygen, forming 
 four atoms of alcohol. The remaining eight atoms of oxygen unite with 
 the remaining four of carbon in the relation of one to two, forming four 
 atoms of carbonic acid gas. Thus the whole sugar is converted into two 
 different substances, of which the yeast forms no part. It only acts the 
 part of a bold revolutioniser, breaking up existing combinations, that new 
 ones may be formed from their elements. Now tannin is found to undergo 
 a similar sort of change as the sugar, when brought into contact with certain 
 substances; and one of the new compounds formed from this transposition 
 is gallic acid. M. Antoine has indeed directly shewn, that a very small 
 quantity of nut-galls is capable of converting a large quantity of tannin 
 into gallic acid, and that galls contain a substance capable of producing 
 
216 
 
 GALLS. 
 
 fermentation amongst the elements of the tannin. The composition of 
 tannin, as compared with that of gallic acid, is as follows : — 
 
 TANNIN. 
 
 18 Carbon. 
 
 12 Oxygen. 
 
 16 Hydrogen. 
 
 GALLIC ACID. 
 7 Carbon. 
 
 5 Oxygen. 
 
 6 Hydrogen. 
 2 Water. 
 
 The action considered to take place during the fermentation of tannin by 
 exposure to the air is, that it absorbs or combines with 8 proportions of 
 oxygen from the atmosphere — 
 
 14- 
 
 4 
 
 One proportion f / 
 
 of tannin ^ ( * / 
 
 f 10 / 
 
 -j 12 O equal to -j g \/ 
 
 ^ 16 H equal to. 
 
 ! 
 
 Oxygen im 
 bibed 
 
 7 2 Equivalents 
 gallic acid. 
 
 2 Water. 
 
 4 Carbonic 
 acid. 
 
 Now, in proportion as gallic acid is inferior to tannin in its dyeing pro- 
 perties, will be the extent of the evil of allowing liquors which contain 
 tannin, and which depend upon it for their dyeing properties, to stand till 
 fermentation begins. In some liquors this commences in the course of 
 three or four days ; much, however, depends upon the temperature. 
 
 But although galls thus contain within them the property of a 
 ferment, it may justly be asked whether sumach, which has in many 
 operations of the dye-house superseded the use of galls, possesses the 
 same property ? That it does possess the property of exciting fermentation 
 in other substances has not yet been determined; but from a number of 
 experiments upon the action of various substances on tannin, it would seem 
 either to induce or facilitate fermentation ; and further, we venture to say, 
 that the tannin in sumach is more readily converted into gallic acid than 
 the tannin of gall-nuts. If the liquor of galls be allowed to stand exposed 
 to the air, it requires a considerable time before its tannin is converted into 
 gallic acid; but there are a number of substances which, if put into it, cause 
 the formation of gallic acid to proceed much more quickly. Among others, 
 tartaric and malic acids possess this property in a high degree. Now, 
 sumach, according to some recent analyses, contains a great quantity of 
 malic acid, which, were we allowed to reason from analogy in chemical 
 science, places it under very favourable circumstances for fermentation. 
 Indeed, in certain seasons of the year, we have known it to ferment in 
 forty- eight hours. Whether this fermentation was induced first by the 
 tannin or by the colouring matter which it contains — for sumach contains a 
 distinct colouring matter — we cannot certainly in the meantime determine. 
 But this we well know, that a very short exposure to the air makes it lose 
 its colouring matter. 
 
GALLS. 
 
 217 
 
 It was found by M. Antoine that a little sulphuric, hydrochloric, or 
 nitric acid, added to a solution of galls, makes it less liable to ferment by 
 exposure. We have often seen a little sulphuric acid put into sumach 
 to cause it to keep, as dyers say; but this weakens its dyeing powers, 
 and unfits it as a good mordant for very deep shades of colour. 
 
 The following table, abridged from Brande’s Manual of Chemistry, will 
 give some idea of the action of some metallic salts upon a solution of galls 
 or sumach : — 
 
 Names of Salts used. 
 Protochloride of manganese, 
 Protosulphate of iron (copperas), 
 Persulphate of iron, . 
 
 Chloride of zinc (muriate of zinc), 
 Protochloride of tin, 
 
 Perchloride of tin, 
 
 Sulphate of copper (blue-stone), 
 Nitrate of copper, 
 
 Nitrate of lead, 
 
 Tartrate of antimony and potash, 
 Tartrate of bismuth and potash, 
 Sulphate of uranium, 
 
 Sulphate of nickel, . 
 Protonitrate of mercury, . 
 
 Colour of Precipitates. 
 
 . Dirty yellow. 
 
 . Purple tint. 
 
 . Black. 
 
 . Dirty yellow. 
 
 . Straw colour. 
 
 . Fawn colour. 
 
 . Yellow brown. 
 
 . Grass green. 
 
 . Dingy yellow. 
 
 . Straw colour. 
 
 . Copious yellow or orange. 
 . Blue black. 
 
 . Green. 
 
 . Yellow. 
 
 In attempting to draw a practical inference from some of these results, 
 we would, for example, conclude that persulphate of iron is much better 
 adapted for dyeing blacks than protosulphate, as the former is mentioned 
 as producing a deep black, while the latter gives only a purple tint. It is 
 much to be regretted that in making out these tables, care has not been taken 
 to give the results in all their bearings. What is mentioned of these two salts 
 is correct at the instant the mixtures are made ; but in the course of twenty 
 minutes the black from the persulphate becomes a brownish slate, whereas 
 the purple tint of the protosulphate changes during the same time to a deep 
 black ; and these changes continue till the former has become a light 
 yellowish slate, and the latter a perfect ink black. 
 
 When trying the difference of effect produced by the persulphate and 
 protosulphate of iron upon pure tannin and gallic acid, it may further be 
 observed, that the changes produced with tannin are somewhat similar to 
 those which occur in a solution of galls. With gallic acid the persulphate 
 gives at first a black precipitate, not so dark as the tannate, but in a few 
 minutes it changes to an olive, and continues changing till it becomes 
 almost colourless. With the protosulphate at first the colour is scarcely 
 visible, but after an hour’s exposure it assumes a rich violet. From these 
 facts it may be concluded that tannin is superior to gallic acid as a dyeing 
 agent for black ; moreover, the compound formed is more insoluble. 
 
 Another circumstance which modifies the results of these experiments 
 
218 
 
 GALLS. 
 
 in their application to dyeing, is the quality of the water used. If the 
 experiments be performed with distilled water, it will be found on repeating 
 them with common spring water, that one-half of the quantity of stuffs will 
 give the same depth of colour; and that the colours, in this instance, have 
 more of a purple hue, and are much more permanent. This may be illus- 
 trated by a very simple experiment. Take two glass jars of equal size, fill 
 them half full with distilled water, and add an equal quantity of a solution 
 of galls or sumach ; put into each an equal number of drops of a solution 
 of protosulphate of iron (copperas) ; the change of colour is scarcely per- 
 ceptible. But fill up one to the brim with spring water, and it almost 
 instantly becomes a dark reddish black. Allow both jars to stand for an 
 hour, the solution with the distilled water will have become a deep violet, 
 while the other, notwithstanding the double quantity of water, is so dark 
 that no light is transmitted; and it will require one -half more water to 
 reduce it to the same shade as the other, but still retaining more of the 
 reddish hue — which, by the way, makes it superior for black. It will also 
 be found to be much more insoluble, and to require a greater proportion of 
 acid to decompose it. If soft or filtered river water be used instead of dis- 
 tilled water, the distinction is not so great, but still the difference is equal 
 to one-half. The best water in our experience for dyeing black, and other 
 saddened colours , gave by analysis sulphuric, muriatic, and carbonic acids, 
 lime, a trace of silica, and iron. The whole solid contents did not exceed 
 one grain in a fluid ounce, or 160 grains per gallon, which, we may remark, 
 is a large quantity (see page 33). These ingredients probably existed in the 
 water as sulphate, carbonate, and muriate of lime, and carbonate of iron. 
 The iron was in very small proportion ; the carbonic acid and lime greatest. 
 
 Now a dyer learning his trade in a work where such water is used, 
 could not fail to become a successful and economical dyer of all saddened 
 colours ; but were he taken from this work to another where soft filtered 
 water was used, what would be the result? When he attempted to dye a 
 black with the same quantity of dye-stuff he formerly used, he would only 
 produce a dark-slate colour ; and if he wished to obtain a slate colour, he 
 would produce a grey. In this dilemma the dyer adds stuff till he comes 
 to the desired shade; -but fancy dyes, bolstered up with stuffs, are not so 
 pretty ; besides, the employer, in consequence of this extra stuff, must 
 either submit to a loss or discharge the dyer — who, no doubt, considering 
 himself ill-used, talks loudly of his ability in dyeing such colours, and offers 
 to prove that the fault is not with him but in the water. Were this wholly a 
 supposed case, we would pause here, and make an apology to our brethren 
 for these remarks ; but not being so, we will rather endeavour to shew that 
 the fault is the dyer’s. Dyeing being an art wholly dependent upon 
 chemistry for its development and successful practice, he who practises it 
 without studying chemistry is like a boy learning to repeat a number of 
 choice sentences from an author without knowing his letters. Had the 
 dyer alluded to known the principles of chemistry, so far as they are appli- 
 cable to his trade, he would, on finding that the same quantity of stuffs did 
 
GALLS. 
 
 219 
 
 not yield the same results, have examined the water to discover where lay 
 the difference, and in this particular case he would find, that instead of 
 adding an extra quantity of sumach, copperas, and logwood, to get a good 
 black, a little chalk and hydrous gypsum (sulphate of lime) added to the 
 water, would so qualify it as to render it equally effective with that to which 
 he had been accustomed. 
 
 There are several kinds of galls, but the following three kinds occur in 
 commerce — Aleppo galls, Smyrna galls, and East Indian galls. These three 
 kinds consist, according to the ripeness of the gall-nuts, of black, green, and 
 white galls. When the galls occur in commerce mixed, they are termed 
 “ natural,” and are sorted into the following kinds: — Picked black, natural 
 black (consisting of black and dark-green galls), dark green, light green, 
 natural white (light green and white galls), and picked white. Aleppo 
 galls are the best ; but under this name must be reckoned not only such as 
 come from Aleppo, but also those derived from Mosul in Natalia, and which 
 are therefore called in Constantinople and Smyrna lists not Aleppo, but 
 Mosul galls. This gall recommends itself by its heaviness, and the lighter- 
 coloured kinds (white and light-green galls) are frequently remarkable from 
 their large size ; but the best distinguishing character between the Mosul 
 and Smyrna galls is the darker kind of the Mosul galls having as it were a 
 bluish bloom, while the Smyrna are of a greyish colour. The Mosul gall, 
 moreover, has not so many tubercules as the Smyrna kind. The first is 
 exported from Constantinople and Smyrna, the latter principally from 
 Smyrna. The chief markets are Trieste, Leghorn, Marseilles, and London. 
 The fourth kind of nut-gall is the marmorated one, which is brought from 
 Puglia ; the chief staple places are Naples and Trieste. It consists generally 
 of large nuts, which have fewer tubercules, and these not acute. They are 
 generally of a whitish -red and greenish colour, sometimes also darker. Istria 
 produces a very inferior kind of galls ; they are small, commonly of a 
 reddish colour, and are much tuberculated. Place of export, Trieste. 
 These are the principal kinds, not to mention others of rare occurrence ; for 
 instance, a kind of gall is brought from Asia Minor and Dalmatia which 
 is hollow, not heavy, and of a reddish colour. 
 
 Analysis of galls by M. Guibourt : — 
 
 Woody fibre, 
 Water, 
 Tannin, 
 Gallic acid, 
 
 . 10-5 The luteo-gallic acid is 
 . 11-5 i applied to the yellow 
 . 65-0 colouring matter of the 
 . 2-0 J galls. 
 
 Ellagin acid and luteo-gallic acid, 2*0"" 
 
 Gum, . 
 Starch, 
 
 Extractive matter. 
 
 2-5 Sometimes white galls 
 2-5 are dyed by a little iron- 
 2- water being put upon 
 
 Chlorophyl, 
 
 Sugar, 
 
 0-7 them, which darkens 
 
 1-3 them, and makes cthem 
 I appear of a better quality. 
 
 100-0 J 
 
220 
 
 SUMACH. 
 
 * Sumach. 
 
 Called by botanists Rhus coriaria, is a native of Syria. It is diligently 
 cultivated in Spain, Portugal, and in some parts of Italy and Sicily, and 
 known in tbe market as Sicily, Malaga, Trieste, and Verona sumach : the first 
 is the best quality. Upwards of 60,000 tons of this dye are used annually in 
 this country. The sumach tree, or rather shrub, grows to a height of about 
 eight or ten feet ; the stems are ligneous, and divide at the bottom into 
 many irregular branches ; the bark is hairy and of a brown colour. The 
 leaves are winged, have seven or eight pair of jagged lobes, and terminate 
 in an odd one. The leaves are placed alternately upon the branches, which 
 are surmounted by flowers of a greenish -white colour. The shoots of the 
 shrub are cut down every year close to the roots, and after being dried 
 are reduced to powder by means of a mill ; the very fine stems are often 
 cut into small pieces, and put amongst the powder. 
 
 We have already referred to the use of sumach in the dye-house ; we 
 speak of it simply as a fit substitute for galls, possessing similar properties, 
 and seemingly passing through similar decompositions by exposure. 
 Indeed, galls are very seldom used now in the ordinary dye-house, only 
 sumach. A little sulphuric acid added to sumach retards fermentation ; 
 but, as already stated, it is not good to add it when dark shades are 
 required, and should only be used for sumach which is to stand for some 
 time, or is to be used for very light drabs. In this case the colour 
 obtained is more pleasant — technically, more sweet ; but either the addition 
 of acid, or by standing exposed to the air, very soon destroys the colouring 
 matter which sumach contains, and also affects the depth of shade of dye 
 obtained from it. It is, therefore, always advisable to use the sumach 
 newly boiled. The comparative advantages of using it newly boiled, and 
 after it has been kept for some time, can easily be ascertained by taking a 
 given quantity, boiling it, and allowing it to stand over a few days ; then 
 taking the same quantity, boiling it the same length of time, heating the 
 old solution to the same temperature as the new, and adding to each the 
 same weight of cotton ; the effects produced will be very different, and 
 will, more than any written description, shew the importance of attending 
 to this circumstance. 
 
 Sumach is generally used as a bottoming when the metallic base or 
 mordant is iron or tin, and for dyeing deep colours, such as blacks, reds, 
 &c. Sicilian sumach has a greenish -yellow colour, and is the best when 
 bright colours of red are to be dyed ; also for barwood, and all colours 
 that require clearness. Verona sumach when compared with Sicilian has a 
 fawn tint ; it is best for deep reds, browns, and blacks. When used for 
 barwood reds the colour is heavy, and to use Sicilian sumach for the pur- 
 poses that Veronian is most suitable, would require about one-half more 
 in quantity for the same weight of cloth. 
 
 The following process for dyeing black will enable us to illustrate 
 
SUMACH. 
 
 221 
 
 some of the reactions of this substance in connection with the metallic 
 bases : — 
 
 The goods are put into a hot decoction of sumach, and allowed to 
 steep for twelve hours ; they are then wrought through lime-water, which 
 gives them a beautiful bluish-green colour, becoming very dark with a 
 short exposure to the air. If allowed to stand for half an hour, the green 
 colour passes off, and the goods assume a greenish-dun shade. When 
 they are at the darkest shade of green, they are put through a solution of 
 copperas ; after working some time in this, and allowing them to stand 
 exposed to the air, they become black. But if dried from this, the colour 
 is only a slate or dark grey. They are again put through lime-water, 
 which renders them brown ; they are then wrought through a decoction 
 of logwood till the colour of the wood has nearly disappeared from the 
 solution. A little copperas is added, which throws of the reddish hue of 
 the wood, giving them a blue shade. This is termed raising the colour. 
 The goods are washed from this in cold water, and dried in the shade. 
 When a deep blue-black is wanted, the goods are dyed blue previous to 
 steeping in the sumach. 
 
 The passing of the goods from the sumach through lime, before intro- 
 ducing them into the iron solution, is not essentially necessary for pro- 
 ducing the colour, but is very useful in facilitating the operation, and in 
 giving depth of hue by the iron. This metal is held by the strong affinity 
 of the acid, but the goods impregnated with lime, being put into the 
 copperas, the lime takes the acid, and the iron takes to the tannin of the 
 sumach. The passing through lime-water from the copperas solution is for 
 the purpose, also, of neutralising the acid of the iron upon the goods, 
 which, as a salt, would act upon the logwood, and precipitate it and injure 
 the operation. Washing in water from the copperas answers equally well, 
 and for fine goods, where a soft tint of black is necessary, is even prefer- 
 able. When the goods are passed through the lime, and put into the log- 
 wood, the presence of the alkali is hurtful to the logwood ; therefore it is 
 best to pass the goods through water before putting them into the log- 
 wood. The action of the iron upon this substance is the same as we have 
 described for galls ; a persalt of iron added or used gives an immediate 
 black, but not permanent, the oxygen seeming to affect the decomposition 
 of the colour m some way. When a protosalt of iron, as copperas, is used, 
 the blackening is slower, but more permanent, shewing that it is the most 
 suitable salt to use. It is, however, to be remarked, that the combination 
 of iron and tannin, forming the black colour, seems to depend on a state 
 of oxidation of the iron a little higher than the protoxide, and much lower 
 than the peroxide ; that the peroxide, when used, is reduced in oxidation, 
 and causes change and loss in reduction, and that the protoxide imbibes 
 oxygen as required ; an opinion urged by the author in the Practical 
 Mechanics ’ and Engineers ’ Magazine, in 1843, and which was advocated 
 afterwards in the Comptes Rendus , the translation of which we take from 
 the Chemical Gazette. 
 
222 
 
 SUMACH. 
 
 “ When a solution of gallic or of tannic acid, which are colourless, and 
 generally form colourless salts or of the colour of the basis, is poured into 
 a solution of the persulphate of iron, an intense blue precipitate is formed, 
 which remains suspended in the liquid. This anomalous fact has fre- 
 quently excited the attention of chemists, MM. Berzelius and Chevreul 
 have even expressed some doubts respecting the simplicity of the reaction. 
 
 “It has long been known that tannin and gallic acid do not precipitate 
 the protosalts of iron when protected from contact with the atmosphere. 
 Berzelius, Chevreul, and Persoz, have, moreover, observed that when gallic 
 acid or tannin is conveyed into a salt of the peroxide of iron, it is always 
 reduced to the state of a protosalt. This fact is easily proved by adding 
 to the blue solution produced by the persulphate of iron in a solution of 
 gallic acid an excess of acetate of lead or of carbonate of lime, which pre- 
 cipitates the blue combination, and at the same time the sulphuric acid. A 
 colourless liquid is separated by filtration, in which the presence of iron 
 may be demonstrated in the state of protoxide. 
 
 “ These experiments are insufficient to explain this curious reaction. It 
 is not improbable to admit, as MM. Berzelius and Chevreul have done a 
 priori , that the oxygen combining with the gallic acid or the tannin 
 converts them into a new acid of a blue colour ; but positive experiments 
 were wanting to decide the point. 
 
 “ When a solution of tannin or of gallic acid is poured by drops into 
 a solution of persulphate of iron in excess, no blue colouring is obtained ; 
 if there is one produced it is only momentary. ISTor is there one formed 
 with the same salt in minimum in presence of chlorine, nor with a protosalt 
 of iron and gallic acid oxidised in various degrees by chlorine, by a salt of 
 silver, or lastly, by the atmosphere in an alkaline solution. 
 
 “ When a solution of gallic acid in excess is conveyed into persulphate 
 of iron, and the liquid thrown down by acetate of lead, a blue paste is 
 obtained, which treated with oxalic acid forms soluble oxalate of iron ; the 
 blue colour disappears entirely, and is restored by acetate of soda. The 
 solution of the oxalate, diluted very much with water, treated cautiously 
 with the two prussiates and sulphuretted hydrogen, presents all the 
 characters of the salts of iron in the state of peroxide and protoxide. 
 
 “ It appears to me that we may conclude from the above facts, that if 
 we start with a protosalt of iron, it is requisite to add oxygen, and if we 
 set out with a persalt, some oxygen must be removed, in order to produce 
 the blue compound, and that this compound contains the two oxides. In 
 the first case the protoxide of iron combines with the oxygen of the 
 atmosphere ; in the second, a portion of the oxygen of the peroxide 
 destroys a corresponding portion of the gallic acid or of the tannin, con- 
 verting it into a brown substance. This substance does not enter into the 
 constitution of the new compound, which must be considered as a salt 
 formed of tannin or gallic acid and of an intermediate oxide of iron, pro- 
 bably of a blue colour, the tint of which is slightly altered by this brown 
 substance. 
 
SUMACH. 
 
 223 
 
 “ To prove in the most evident manner that the blue colouring is not 
 to be ascribed to a blue acid, but to a particular oxide, I endeavoured to 
 obtain other blue salts with mineral acids — for instance, with sulphuric acid. 
 For this purpose I prepared some mixtures in variable proportions of the 
 protosulphate of iron and of the persulphate, and to avoid an inevitable 
 separation of the two salts from their different degrees of solubility, I 
 removed immediately the water by adding to the solution concentrated 
 sulphuric acid in large excess, taking care to produce as little heat as 
 possible. In this manner I obtained a thick paste of a deep blue, the tint of 
 which was more or less pure according to the proportions of the two salts 
 of iron; I likewise produced a blue sulphate, but of very ephemerous 
 existence, by evaporating rapidly a mixture of the two salts of iron ; 
 the blue tint appeared at the moment when the mass was nearly dry. 
 On substituting phosphate of soda for the sulphuric acid, I obtained 
 a deep-blue phosphate of iron and some sulphate of soda, which removed 
 the water immediately. I endeavoured, but without success, to prepare 
 combinations with other salts ; the hyposulphite of soda alone afforded an 
 intense blue colouring, but of remarkable instability. This is not sur- 
 prising : there are many instances in chemistry of bases which prefer com- 
 bining with certain acids and refuse to unite with others — such, for instance, 
 among others, is the protoxide of copper. 
 
 “ I made numerous experiments to obtain the blue oxide in a free 
 state ; I succeeded several times, but under circumstances which I was not 
 able to produce at will. It is, however, a well-known fact, that when 
 a protosalt of iron is precipitated with ammonia in contact with the atmo- 
 sphere, the white precipitate of the protoxide soon becomes green, passing 
 first, however, through blue. 
 
 “ The impossibility of obtaining the blue sulphate of iron in a crystal- 
 line state, and of isolating the acid of the blue gallate compound, prevented 
 me from having recourse to analysis in order to arrive at the formula for 
 these -intermediate salts : I was forced to proceed by synthesis, which I 
 confess is far from being accurate, and it is with some doubts that I 
 publish the results. 
 
 “ Of all the mixtures of protosulphate and persulphate which I ex- 
 perimented on, that which afforded the most pure blue with sulphuric and 
 gallic acids and&vith the phosphate of soda, contained precisely three 
 equivalents ®f protosalt to two of the persalt — proportions which corre- 
 spond to the cyanide Fe 7 0 9 , Prussian blue. 
 
 “ If, as I trope, I have rendered probable the existence of two inter- 
 mediate oxides of iron, capable of forming salts and of entering into the 
 salts with their peculiar colour, I shall have thrown some light on the 
 various tints produced by the different kinds of astringent substances, 
 morphine, salicylic acid, and some other organic principles ; and likewise 
 on the production of violet, black, brown, and green tints, with red and 
 yellow colouring principles, in presence of salts of peroxide of iron. I 
 have convinced myself that all the yellow-colouring substances (for 
 
224 
 
 CATECHU. 
 
 instance, curcuma) do not produce green ; that the red colouring prin- 
 ciples (among others aloetic acid) do not give a violet; and that when 
 there is a production of green (as with the Persian berries and the quer- 
 citron), or of violet (as with madder, logwood, &c.), the phenomena are 
 identical with those which occur with tannin and gallic acid. These 
 observations agree, moreover, perfectly with the suppositions of M. 
 Thenard, with the facts published by M. Kochlin-Schouch, and by M. 
 Schlumberger, and which M. Stackler informs me he has found confirmed 
 in his establishment, that the iron mordants should be at a fixed degree of 
 oxidation to produce beautiful dyes.” 
 
 Catechu. 
 
 This is another substance containing much tannin. We have already 
 noticed some of its peculiarities, but may state further that it is a dry 
 extract prepared from the wood of a species of sensitive plant, named 
 Acacia catechu. It was long considered an earthy substance, and termed 
 terra Japanica. The plant is indigenous to Hindostan, and flourishes 
 abundantly in mountainous districts. It grows to about twelve feet in 
 height ; the trunk is about a foot in diameter, and covered with a thick 
 dark-brown bark. The extract which is obtained from the tree is made 
 from a decoction of the wood. As soon as the trees are felled, all the 
 exterior white wood is carefully cut away, the interior, or coloured wood, 
 is then cut into chips ; narrow-mouthed unglazed pots are nearly filled 
 with these, and water is added to cover them. Heat is applied, and when 
 half the water is evaporated, the decoction, without straining, is poured 
 into a shallow earthen vessel, and further reduced two-thirds by boiling. 
 It is then set in a cool place for a day, and is afterwards evaporated by the 
 heat of the sun, care being taken to stir it occasionally during that process. 
 When it is reduced to considerable thickness it is spread upon a mat or 
 cloth, which has been previously covered with the ashes of cow dung, and 
 this mass, divided by a string into quadrangular pieces, is completely dried 
 in the sun, and is then fit for sale. 
 
 It is a brittle, compact substance, of a dark-brown or chocolate colour ; 
 has no smell, but a very stringent taste ; is soluble in water ; contains a 
 great amount of tannin, and a peculiar acid, which has been named 
 catechuic acid, or catechuin, with a formula C 20 H 18 O 8 H 2 O, which passes 
 into other compounds by oxidation, &c. It is the reactions of these 
 ingredients with oxygen and other chemical agents, that constitute its 
 dyeing properties. A solution of catechu in water is of a beautiful reddish- 
 brown colour, which ought to be kept in mind in perusing the following 
 summary of the reactions of other substances upon it : — 
 
 Acids brighten the colour of the solution ; alkalies darken it, and the 
 shade deepens by standing; protosalts of iron give olive-brown precipitates 
 persalts of iron also give olive-brown precipitates, but with more green 
 
CATECHU. 
 
 225 
 
 than those of the protosalts; salts of tin give yellow-brownish precipitates ; 
 nitrate and sulphate of copper, yellowish-brown; acetate of copper, a 
 brown precipitate ; salts of lead, brick-coloured precipitates ; bichromate 
 of potash, a deep red-brown. These reactions alone indicate how very 
 important an agent catechu is in the hands of the dyer, and how very 
 extensive its applications in the processes of his art. 
 
 Ihere are various qualities of catechu in the market, differing con- 
 siderably in their value as dyes. The Bombay catechu is met with in 
 square masses, of a reddish-brown colour, which, when broke, exhibit a 
 uniform texture. Its composition is as follows:— 
 
 Tannin, 
 
 Gum, . rj 
 
 Extractive matter, 34 
 
 Impurities, 
 
 100 
 
 “ Extractive matter ” is a sort of indefinite term, applied to designate 
 a brown matter extracted from vegetables when boiled; its true nature is 
 not known, but the part it may play in the reactions of catechu is probably 
 important, and is at least not to be overlooked. 
 
 Bengal catechu is met with in flattish round lumps, of a light-brown 
 colour outside, but dark internally. It gives— 
 
 Tannin, 
 
 Gum, . 
 
 Extractive matter, 
 Impurities, . 
 
 49-5 
 
 7-0 
 
 36-5 
 
 7-0 
 
 
 100-0 
 
 Malabar catechu is imported in large masses, of a light-brown colour 
 outside, dark within, and covered with leaves. It gives— 
 
 Tannin, 
 
 Gum, . 
 
 Extractive matter, 
 Impurities, . 
 
 •• 
 
 45-8 
 
 8-0 
 
 39-9 
 
 6-3 
 
 
 
 100-0 
 
 There is a sort of catechu brought to this country from India in small 
 cubical masses, about an inch in size. This is a very inferior quality, and, 
 as imported, is easily known from genuine catechu. Sometimes, however, 
 means are resorted to, to alter the colour of this spurious article, and make 
 it more difficult to be detected. It is said often to contain a great quantity 
 of roasted starch, or British gum, termed dextrine. 
 
 Catechu is often adulterated by other vegetable extracts, and also by 
 sand, clay, and ochre. These last impurities maybe readily detected by 
 dissolving a portion of the catechu in water, when any of them contained 
 
226 
 
 CATECHU. 
 
 in it will be precipitated ; or by burning a little of it in a crucible until 
 all organic matter is consumed, the latter adulterants will remain. We 
 have examined samples of catechu of good colour, having 8|- per cent, of 
 clay and sand mixed with them. Good catechu is all soluble in cold water, 
 and gives a clear solution. 
 
 The tannin which is in catechu is not converted into gallic acid by 
 exposure so easily as that in galls ; but it is subject to oxidation. When a 
 portion is dissolved in water, the solution has a gummy character, and 
 goods put into it would be affected as by a weak solution of gum; the 
 threads of yarn, for example, adhere when dried out of it. The addition of 
 a metallic salt destroys this viscous quality, and those salts answer best, or 
 are most effectual for that purpose, which yield their oxygen most easily. 
 Accordingly, the salts of copper are most commonly used, and they are 
 added to the dissolved catechu before putting in the cotton. The chemical 
 changes which catechu undergoes in the operations of dyeing are not yet 
 well understood. The result, however, depends upon oxidation — hence 
 substances that give oxygen are used with it. The action has been ex- 
 plained in this way : — The copper salt oxidises a portion of, or a certain 
 compound in, the catechu, which, although insoluble in water, is soluble 
 in deoxidised catechu; therefore, the whole is held in solution in the bath ; 
 the goods become impregnated with this solution, and as the whole of the 
 catechu upon the cloth becomes oxidised, it becomes also insoluble. This 
 explanation does not account for all the phenomena occurring during the 
 dyeing of browns, &c., with this substance; for if we take two portions 
 of a solution of catechu, and to the one add a salt of copper, to the other a 
 salt of zinc, pass the cloth from these through a solution of lime, and 
 expose to the air, the piece treated with the zinc will become dark brown, 
 but not that treated with the copper. The above explanation would lead 
 us to expect the opposite, as copper yields its oxygen more easily than 
 zinc. When catechu is oxidised, there is formed an acid nearly of the 
 composition of gallic acid, which has a deep-brown colour. This is formed 
 when catechu in solution is treated with alkaline matters. The lime, 
 therefore, in the above experiment, may have acted the principal part ; 
 but cotton from catechu solution, put through acetate of lead, also 
 gives a deep-brown colour without alkali. When goods impregnated with 
 catechu are passed through bichromate of potash, there is obtained a deep 
 brown: an oxidation of the catechu takes place at the expense of the 
 chromic acid. Whether the oxide of chromium may act as a base on any 
 part of the dye, we cannot positively affirm, but we think so ; for on burning 
 cotton dyed brown by this means, there is obtained in the ash the oxides 
 both of chrome and of copper, shewing that both the copper and chrome 
 used play a part in forming the dye, and that the dye by this method is 
 something more than mere oxidation of the catechu, as in passing the cloth 
 from the catechu through bleaching liquor, it also gives an immediate 
 brown, but wanting the richness of that by chrome. 
 
 The reactions of catechu are so varied, that it is now used for almost 
 
MYROBALANS. 
 
 227 
 
 all compound colours — blacks, browns, greens, drabs, and fawns — both in 
 cotton and wool ; and its permanency renders these colours of high estima- 
 tion in the market. 
 
 The following is the analysis of a sample of catechu by Mr. Cooper, 
 giving a wider range to the matters contained in it, and which will serve to 
 give some better idea of the varieties of this substance; for, from its mode 
 of preparation, probably no two samples will give the same proportions 
 
 Tannin, 
 
 62-8 
 
 Extractive, or colouring matter, . 
 
 8-2 
 
 Resinous matter, .... 
 
 2-0 
 
 Gummy matter, .... 
 
 8*5 
 
 Insoluble matter, 
 
 4*4 
 
 Water, ..... 
 
 12-3 
 
 
 98-2 
 
 Valonia Nuts. — These are the cups of the acorn from the valonia 
 oak, which grows in the Dardanelles and the islands of the Archipelago, 
 and throughout all the maritime ports of Asia Minor. They are imported 
 in great quantities from Smyrna and its neighbourhood. These contain a 
 great quantity of tannin, and also gallic acid ; but they are inferior to 
 sumach or galls for dyeing cotton, and for giving depth of colour with the 
 salts of iron. For silk, however, they possess some peculiarities exceed- 
 ingly valuable for deep blacks, giving a permanency not obtained with 
 ordinary galls; and, moreover, the production of the proper black with 
 valonia nuts upon silk requires a certain treatment whieh it is not every 
 dyer has yet attained, particularly in Scotland, as Scotch dyers are yet 
 behind in silk dyeing. We cannot, for instance, furnish a black upon silk 
 which will withstand unchanged all the operations which a hat undergoes 
 in the process of manufacture — for which purpose we understand the 
 valonia black is applied. 
 
 Divi Divi, or Libi Davi , is the pod of a leguminous shrub, a native of 
 South America; it has been tried as a dye instead of galls or sumach, but 
 is not much used. 
 
 Myrobalans. This is the fruit of a tree which grows in India; it is 
 imported into this country in various forms, has a pale-yellow colour when 
 new, but becomes darker by age, and then resembles dried plums. It 
 contains tannin, and is sometimes used on that account for the operations of 
 dyeing. Its reactions with iron, tin, and alum, are similar to those of 
 sumach, but of less value. 
 
 Oak bark contains a great quantity of tannin, and is used on that 
 account for tanning skins ; but it is not much employed in the dye-house, 
 although it may be used for similar purposes to sumach. The chestnut, 
 both nut and tree, is ground to powder and sold to the dyers for its 
 tannin, under the name of “ Damajavag.” The bark of the mangrove tree 
 also contains tannin in considerable quantity ; there are, indeed, very 
 
228 
 
 TANNATES. 
 
 few vegetable substances which have not in their composition more or 
 less of tannin, and which may be used in virtue of this property instead of 
 galls or sumach ; but the quantity of tannin in them being much less than 
 in sumach, they are not cultivated for that purpose. The bark of the ash, 
 willow, hazel, birch, broom, &c., are often used for dyeing woollens by 
 country people; and some of these substances possess peculiar dyeing 
 properties. The husks of several nuts also contain much tannin. The 
 walnut, for instance, has been long used and much esteemed by the French 
 dyers for woollen stuffs; it gives very fast shades, without previous mor- 
 danting, although alum is sometimes used to give variety. The outer peel 
 of this nut is collected for the dyers ; they are put into large casks, with 
 water poured over them, and kept for a year or more, as they improve 
 when this process of maceration is prolonged. The roots of the walnut 
 tree are also used for dyeing browns. The husks of the horse-chestnut 
 likewise possess dyeing qualities, and might be applied advantageously for 
 some purposes. Mahogany sawdust, although not affected much by 
 mordants, possesses dyeing properties of considerable value, yielding with 
 iron a variety of shades of great permanence and beauty. 
 
 Many of the dye-woods which are used for their colouring matter 
 contain tannin, the action of which upon the mordants is often very inju- 
 rious to the tint. Many varieties of the different woods, giving the same 
 colour, depend much upon the presence of tannin. The whole woody 
 matter being boiled to extract the colouring matter, the tannin is also dis- 
 solved, and it is sure to act upon the mordant in the process of dyeing, 
 producing an effect very similar to that of adding a little sumach to the 
 colouring matter. In many cases this is done beneficially, but in other 
 cases it would deteriorate the tint required. In such cases the presence of 
 tannin in the colouring matter obtained from the wood does not suit. The 
 late Mr. Warrington proposed, as a practical means of ascertaining the 
 quantity of tannin in any matter, the following test : — Premising that a 
 solution of gelatine, isinglass, or glue precipitates tannin : by making a given 
 quantity of this solution and adding drop by drop to a given quantity of 
 the substance to be tested for tannin, also in solution, as long as a preci- 
 pitate is formed, and marking on the alkalimeter the quantity of gelatine 
 used ; every three grains of pure gelatine are equal to two grains tannin, 
 and accordingly it is easy to arrive at a near approximation of the quality 
 of these dye-stuffs. This operation will, no doubt, require a little expe- 
 rience, but it is easily performed, and well deserves attention. 
 
 Several operatives who have practised this method have found it very 
 useful in comparing different sumachs and other dyes containing tannin. 
 
 The following is the range of tannin in the different substances : — 
 
 Oak bark, from . . 11 to 16 
 
 Sumach, ,, . 12 ,, 18 
 
 Divi divi, ,, . . 18 ,, 25 
 
 See also under Receipts. 
 
 Nut-gall, from 
 Valonia, ,, 
 Catechu, ,, 
 
 . 58 to 66 
 . 40 „ 45 
 . 40 „ 52 
 
INDIGO. 
 
 In the few introductory remarks we made upon vegetable colours we men- 
 tioned that, besides the green of leaves and the colours of flowers, which 
 we considered common to all vegetables, there were other colouring 
 matters, which existed only in certain kinds of vegetables, and in par- 
 ticular parts of the vegetable. Indigo is one of these: it belongs to a 
 genus of leguminous plants found in India, Africa, and America, named 
 Indigofera. Botanists have described about sixty species of this genus. 
 These all yield indigo ; but the species from which it is usually extracted 
 are the I. anil , the I. argentea , and the I. tinctoria. It is also extracted 
 from a tree very common in Hindostan (the Nerium tinctorium of botanists), 
 and from the woad plant (Isatis tinctoria ), which is a native of Great 
 Britain, and of other parts of Europe. The colouring matter of these 
 plants is wholly in the cellular tissue of the leaves, as a secretion or juice 
 — not, however, in the blue state in which we are accustomed to see indigo, 
 but as a white substance, which, as we shall presently see, remains white 
 so long as the tissue of the leaf remains perfect. When this tissue is by 
 any means destroyed, the indigo absorbs oxygen from the atmosphere and 
 becomes blue. 
 
 The use of indigo as a dyeing agent dates back to the remotest anti- 
 quity, and so also does the knowledge of the drug as we possess it, which is 
 evidenced by its name nil , which, according to Sir William Jones, is the 
 Hindoo word for blue. It was known by the same name to the Arabs, 
 Egyptians, and other nations of the East, from which circumstance it is 
 supposed that it originally was imported from India. The Greeks and 
 Romans used it as a paint, and Pliny conceived it to be a slime collected in 
 the scum of the sea. The indigo dye was known, however, to nations who 
 had no intercourse with India, and also by people who did not know indigo 
 as a separate drug from the plant. Csesar states that the ancient Britons 
 made their blue dye from the woad plant, and that their wives and daugh- 
 ters, when they appeared naked at the sacred festivals, had their bodies 
 dyed with it, so that they resembled the Ethiopians. That indigo was used 
 as a dye by the ancient Egyptians is proved by the analyses of the blue 
 upon mummy cloths ; and as indigo-producmg plants are said to grow wild 
 in certain parts of Palestine and Egypt, and the blue colour was in high 
 esteem and symbolical of heaven, there is strong evidence that the 
 dyeing of blue with indigo or indigo plant goes back to the earliest ages 
 in man’s history. At the same time there may have been, and really 
 were, nations that dyed blue with the plant, yet did not know indigo 
 in the sense that we now know it. Its value as a dye-stuff was not known 
 
230 
 
 INDIGO. 
 
 in Europe till nearly the close of the sixteenth century, when it was im- 
 ported from India by the Dutch ; and our legislators for a long time pro- 
 hibited its use in England under severe penalties. These prohibitions 
 continued in force till the reign of Charles II., and the reason assigned 
 was, that it was a corrosive substance, destructive to the fibres of the cloth, 
 and therefore calculated to injure the character of the dyers of this country. 
 This opinion, no doubt, sprung from the strong and interested opposition 
 to its use by the cultivators of the woad, which was then regarded as an 
 important branch of national industry. 
 
 “When indigo was first introduced, only a small quantity was added 
 to the woad, by which the latter was much improved ; more was afterwards 
 gradually used, and at last the quantity became so large that the small 
 admixture of woad served only to revive the fermentation of the indigo. 
 Germany thus lost a production by which farmers, merchants, carriers, and 
 others acquired great riches. In consequence of the sales of woad being 
 so much injured, a prohibition was issued against the use of indigo in 
 Saxony in the year 1650 ; and in the year 1652 Duke Ernest the Pious 
 caused a proposal ta be made to the diet by his envoy, that indigo should 
 be entirely banished from the empire, and that an exclusive privilege should 
 be granted to those who dyed with woad. This was followed by an im- 
 perial prohibition of indigo on the 21st of April, 1654, which was enforced 
 with the greatest severity in his dominions. The same was done in France ; 
 but in the well-known edict of 1669, in which Colbert separated the fine 
 from the common dyers,, it was stated that indigo should be used without 
 woad, and in 1737 dyers were left at liberty to use indigo alone, or to em- 
 ploy a mixture of indigo and woad.” — Barlow’s Manufactures and Machinery 
 of Great Britain. 
 
 The plant which yields the indigo in Bengal is a small straight 
 plant, with thin branches, which spread out and form a sort of tuft ; 
 the average height is 4 feet, but on good ground it sometimes attains a 
 height of even 7 feet. The leaves are soft, and somewhat like those of 
 the common clover, and the blossoms are of a light-reddish colour. The 
 plant is at its greatest perfection, and yields the greatest quantity of 
 indigo, when in full blossom. 
 
 There are two methods of extracting the colouring matter from the 
 leaves : the first is by fermentation and beating. This process is conducted 
 in two large brick cisterns or vats, built in relation to one another like 
 two steps of a stair. The upper one is termed the steeper, because in it 
 the fermentation is conducted.. At the bottom of this cistern there is a 
 plug-hole through which, when the process of fermentation is finished, the 
 fluid is run off into the lower cistern, denominated the beater, because in 
 it the process of beating the fluid with paddles, to separate the feculse from 
 the water, is perform.ecL The plant, when cut, is tied up in bundles about 
 5 feet in circumference, and conveyed as quickly as possible to the vat ; 
 for, were it kept but a short time in heaps, the indigo in the plant would 
 be destroyed. The upper vat is filled to about 5 or 6 inches from the top 
 
INDIGO. 
 
 231 
 
 with these bundles, laid in regular tiers. To prevent the throwing up of 
 the herb by the swelling and agitation caused by the fermentation, there 
 are irons built in the two side walls, opposite to one another, to which are 
 fastened beams of wood, which traverse the whole length and breadth of 
 the vats. When the vat is sufficiently filled with the vegetable, a strong 
 grating of bamboo, large enough to cover the whole surface, is laid over 
 the plant, and fastened down by the cross beams. These operations 
 being completed, cold water is poured as quickly as possible into the 
 vat, till it is within 3 or 4 inches of the upper edge. In a short time 
 fermentation commences, and is completed in from nine to twelve hours. 
 Towards the end the action is very brisk, swelling and throwing up frothy 
 bubbles, which sometimes rise like pyramids. These bubbles are white at 
 first, but after a little exposure to the air they become blue, and then 
 purple. This part of the operation requires great skill. If the fermenta- 
 tion be continued too long, the indigo will be much damaged ; and if too 
 short, the quantity is much diminished. When the liquor ceases to swell, it 
 is let out into the second or beating vat, and is then of a light-green colour. 
 
 The liquor being now in the lower or beating vat, a number of men 
 enter it, furnished with oar-shaped paddles about 4 feet in length ; they 
 continue to walk backwards and forwards, agitating or beating the liquor 
 with these paddles. At the commencement of this agitation the liquor 
 begins to froth ; but this is prevented, provided the fermentation has not 
 gone on too long, by adding a little oil. In the course of an hour and a 
 half the liquor begins to granulate and assume the appearance of agitated 
 water, full of wood grounds or sawdust. This part of the process also 
 requires considerable care and management ; for, if the beating be stopped 
 too soon, the indigo will not be all separated from the liquor, occasioning 
 a proportionate loss ; if continued too long, the granulated particles are 
 broken, and disposed through the liquor, and do not readily fall to the 
 bottom. When the beating is completed, the grounds are allowed to settle ; 
 the grains which constitute the indigo fall to the bottom,, and the supernatant 
 liquor is let off by plug-holes in the side of the vat. The precipitate is 
 then removed to a copper boiler, which is kept heated till the liquor becomes 
 as thick as oil. Some manufacturers bring it to this state by causing the 
 liquor to boil; others by keeping it at a moderate temperature. The former 
 process produces lighter coloured indigo than the latter. In this state 
 it is put into a large flat vessel, furnished at the one end with a close filter. 
 After most of the liquor has filtered through, the indigo remains in the 
 vessel about the consistence of butter. It is then put on proper frames, 
 and subjected to considerable pressure by a sort of screw-press, and 
 afterwards cut into small cakes, which are placed upon boards in a 
 drying stove ; when dry, these cakes are packed up, and in this state form 
 the indigo of commerce. 
 
 The other method of extracting the indigo from the plant differs from 
 that described only in the first operations. Instead of putting the plant 
 into the vat when newly cut, it is spread out to dry in the sun for two days, 
 
232 
 
 INDIGO. 
 
 and then thrashed to separate the leaves from the stems. The leaves are 
 then kept until they have changed from a green to a bluish-grey, or 
 lavender colour; they are then put into the first vat with warm water, and 
 kept stirred till the leaves are so completely wetted as to sink. The liquor 
 is then instantly let off into the beating vat, where it is treated as already 
 described. 
 
 The chemical changes which take place during these operations are not 
 well understood, and the various opinions expressed by chemists concerning 
 them are not very easily reconciled. Berthollet, in his Elements of Dyeing, 
 while describing the process of the first or fermenting vat, says — “In the 
 first a fermentation is excited, in which the action of the atmospheric air 
 does not intervene, since an inflammable gas is evolved. There probably 
 results from it some change in the composition of the colouring particles 
 themselves, but especially the separation or destruction of a yellowish sub- 
 stance, which gave to the indigo a greenish tint, and rendered it susceptible 
 of suffering the chemical action of other substances. This species of fer- 
 mentation passes into a destructive putrefaction, because the indigo, as we 
 shall see, has a composition analogous to that of animal substances.” 
 
 Dr. Ure, in his Dictionary of the Arts and Manufactures , says that from 
 some experiments made upon the gases given off during fermentation, they 
 were found to be composed, when taken about the middle of the operation, 
 of 27-5 of carbonic acid gas, 5*8 of oxygen, and 66-7 of nitrogen, in the 100 
 parts ; and towards the end of the operation. they consisted of 40*5 of car- 
 bonic acid gas, 4*5 of oxygen, and 55 of nitrogen. No carburetted hydrogen 
 is disengaged. “ The fermenting leaves,” using the Doctor’s words, 
 “ apparently convert the -oxygen of the air into carbonic acid, and leave its 
 nitrogen free.” They also evolve a quantity of carbonic acid spontaneously. 
 It will be observed that these two opinions are decidedly contradictory: the 
 one says that the action of the atmosphere does not intervene, and that an 
 inflammable gas is evolved; the other, that there is no inflammable gas 
 evolved, and that the air is apparently the principal agent in effecting the 
 various changes. But when we recollect that the leaves are all under the 
 liquor, and kept so by the fixed position of the beams, there can be little 
 contact between the fermenting leaves and the air, except that held by the 
 water and among the leaves, and in the plants themselves — hence the con- 
 version of its oxygen into carbonic acid gas must be very limited. 
 
 Sir Robert Kane says of this process— “ After some time a kind of 
 mucous fermentation sets in ; carbonic acid, ammonia, and hydrogen gases 
 are evolved, and a yellow liquor is obtained, which holds the indigo dis- 
 solved. The theory of this action is, that by the putrefaction of the vegeto- 
 animal matter of the leaves, the indigo is kept in the same white soluble 
 condition in which it exists in the plant.” 
 
 Dr. Thomson, in his Vegetable Chemistry , supposes that the indigo 
 exists in the plant in union with another substance, and during fermentation 
 that substance is decomposed, and carbonic acid gas consequently evolved. 
 But we will give his own words: — “The leaves of the indigofera yield a 
 
INDIGO. 
 
 233 
 
 p'een infusion to hot water, and a green powder may be precipitated from 
 it ; but unless a fermentation has taken place, neither the colour nor the 
 properties have any resemblance to those of indigo. There is little doubt 
 that in the leaves it exists in the state of white or deoxygenated indigo , and 
 that during the fermentation it combines with the requisite quantity of 
 oxygen to convert it into blue indigo. The evolution of carbonic acid gas 
 renders it not unlikely that the white indigo was in combination with some 
 principle (probably of an alkaline nature) which was decomposed during 
 the fermentation.” ° 
 
 These discrepancies of opinion relative to the nature of the changes 
 which take place during fermentation, shew that proper investigations have 
 not yet been made into this part of the process : and it is obvious that until 
 this is done, any hypothesis founded upon statements concerning the gases 
 evolved must be unsatisfactory. The supposition hazarded by Dr. Thomson 
 certainly appears to us the most consistent ; for as deoxidised indigo com- 
 bines readily with alkaline substances, and as the vegetable alkalies almost 
 always contain nitrogen, we can easily conceive of that gas being evolved 
 either free or in combination with hydrogen, forming ammonia. It may 
 yet be found that indigo, like gallic acid, does not exist in the living vege- 
 table, but is the result of a decomposition of some more complicated 
 compound. 
 
 The chemical action which takes place in the second vat in which the 
 beating process is conducted is apparently much more easily explained, 
 and therefore the discrepancies among writers on the subject are not so 
 great. We shall give only two quotations. Berthollet says— “ Hitherto the 
 colouring particles have preserved their liquidity. In the second operation 
 the action of the air is brought into play, which, by combining with the 
 colouring particles, deprives them of their solubility, and gives them 
 the blue colour. The beating serves at the same time to dissipate the 
 carbonic acid formed in the first operation, which action is an obstacle 
 to the combination of the oxygen.” Dr. Ure’s opinion is thus expressed :— 
 
 U The object of the beating is threefold: first, it tends to disengage a 
 great quantity of carbonic acid present in the fermented liquor ; secondly 
 to give the newly-developed indigo its requisite dose of oxygen by the 
 most extensive exposure of its particles to the atmosphere ; and, thirdly, 
 to agglomerate the indigo in distinct flocks or granulations. In order to 
 hasten the precipitation, lime-water is occasionally added to the fermented 
 liquor in the progress of beating; but it is not indispensable, and has been 
 supposed to be capable of deteriorating the indigo.” 
 
 _ That the liquor in the beating vat absorbs oxygen from the air as the 
 indigo separates from it, has, we believe, been ascertained by direct experi- 
 ment ; and it is also known to manufacturers that the sunshine assists in 
 the separation of the indigo from the liquor. But though these facts may 
 have been ascertained, it does not give us any positive information respecting 
 the nature of the change which takes place in the vat; neither can we 
 expect such information till it be ascertained what keeps the indigo in 
 
234 
 
 INDIGO. 
 
 solution previous to the operation of beating. Both oxygenised and deoxy- 
 genised indigo are insoluble in water ; there must therefore be some 
 substance in the liquor capable of holding the indigo in solution previous 
 to being beat. According to our present knowledge of the nature of white 
 or deoxidised indigo, there is no other substance can hold it in solution 
 except the alkalies and alkaline earths. But during such generation and 
 emission of carbonic acid gas, the existence of any known alkali capable of 
 holding the indigo in solution in those vats is next to impossible, and 
 the results prove this ; for while the acid is liberated the indigo be- 
 comes more insoluble — a result which is just the opposite of what we 
 conceive would take place were an alkali present — unless we suppose that 
 the carbonic acid is the result of the decomposition of the alkali or 
 alkaloid, or is evolved, as already hinted, from the decomposition of a 
 substance which is resolving itself into indigo. 
 
 Dr. Schunck may be said to have discovered that it is a fact that the 
 indigo results from the decomposition of a more complicated compound, by 
 researches upon the Isatis tinctoria , or woad. He found in this a substance 
 very soluble in water, which he called indican, composed of C26H 3 iN 0 17 . 
 This substance, with two proportions of water, forms into two other 
 compounds, thus — 
 
 Indican. Indigo. Iryliglucine. 
 
 c 26 h 31 no 17 o 2 h 2 o = C 8 H 5 NO + 3 C 6 II 10 O 6 . 
 
 The indican forms a light-brown, syrupy, bitter mass, which has an acid 
 reaction with test paper. It yields, under the influence of ferment or acids, 
 indigo blue sugar. Dr. Schunck considers in every case indican is the 
 parent substance of indigo, which under the influence of a ferment produces 
 white indigo and sugar. The Doctor also shews that if care is not taken 
 the indican is liable to undergo rapid modifications, and may yield other 
 substances than indigo blue ; hence the great care required in the manu- 
 facture of indigOj that the fermentation may be conducted to a proper 
 point. 
 
 Having given the opinions of several chemists upon the chemical nature 
 of the manufacture of indigo, and hinted at the difficulties which some of 
 these theories involve, we shall now consider the nature of indigo; and 
 whatever be the chemical changes which take place in the beating operation, 
 we are certain that the indigo is precipitated in union with various other 
 substances, rendering it very impure. The best indigo of commerce, 
 according to several analyses, contains only 75 per cent, of pure indigo, 
 while some of the inferior kinds do not contain above 29 or 30 per 
 cent. Part of these impurities may be dissolved out with water, alcohol, 
 dilute acids, or alkaline leys. Berzelius found these impurities to consist, 
 besides a little iron, of clay, lime, magnesia, silica, and a substance 
 resembling vegetable gluten, which may be obtained by digesting indigo in 
 dilute sulphuric acid (vitriol) ; also a brown matter , which he termed indigo 
 brown, and which he obtained by digesting the indigo in strong potash ley 
 
INDIGO 
 
 235 
 
 after the gluten had been extracted. He found likewise a red resinous sub- 
 stance, which he termed indigo red; it was obtained by boiling the indigo 
 in alcohol, after digestion in the acid and alkali. Several experiments have 
 been made upon the colouring properties of these substances, but the 
 results have shewn that they are incapable of being used as dyes. On the 
 contrary, as we shall afterwards have occasion to remark, some of them 
 being more soluble than the pure indigo, and much more easily decomposed, 
 their presence is very hurtful, especially when the indigo is to be used as 
 sulphate of indigo. 
 
 From the great differences in the quality of indigo, it would be of the 
 utmost importance to the dyer to have an easy method of ascertaining its 
 true value. This, so far as we are aware, has not yet been obtained ; the 
 various methods proposed generally imply formal analyses, which, how- 
 ever important they may be to the dyer, are too delicate and tedious 
 to be generally adopted. The method practised by the dyer is that 
 of comparison — putting several samples together, and breaking and com- 
 paring their clean surfaces. The best indigo generally is of the deepest 
 violet blue, and the finest grain, and if scratched with the nail it presents a 
 copper hue ; but notwithstanding great care and long practice in judging 
 of the value of indigo in this way, it often happens that the lot chosen 
 turns out to be of inferior quality — a fact which is not discovered until it 
 is in the vats. 
 
 The process of Berzelius is to take a weighed quantity of the indigo 
 of commerce in very fine powder, and after digesting it in dilute sulphuric 
 acid, to filter and wash it ; then digest what remains on the filter in strong 
 potash or ammonia ; filter and wash again, then boil the remainder in 
 strong alcohol ; what remains is pure indigo, and, by weighing it, we 
 find the percentage of real indigo in the sample. 
 
 Another process, somewhat similar, was recommended by Chevreul. 
 He treated the powdered indigo first with water, then with alcohol, and 
 afterwards with muriatic acid. The following is the result of his experiment, 
 taking 100 parts : — 
 
 ( Green matter united to ammonia, \ 
 
 Treated with \ A little deoxidised indigo, I 
 
 water. j Extractive, r ^ P ar ^ s - 
 
 ( Gum, j 
 
 Treated with j matter, | 
 
 Red resin, V30 ,, 
 
 ( A little indigo, j 
 
 alcohol. 
 
 r Red resin, 6 
 
 Treated with J Carbonate of lime, 2 
 
 muriatic acid. Red oxide of iron, 2 
 
 Alumina, 3 
 
 There Silica, 3 
 
 remained, ( Pure indigo, 42 
 
 100 
 
236 
 
 INDIGO. 
 
 Although these processes give a much nearer and more certain 
 approximation to the true value of indigo than the mere comparison of 
 samples by the eye, still they are not direct enough, and require too much 
 nice management to be resorted to generally in the dye-house. Many 
 indeed, who are most affected by a bad bargain, and ought to be most 
 interested in any process that would enable them to avoid loss, and who 
 have the requisite time and means to try such experiments, do not seem 
 impressed with the importance of such inquiries. 
 
 Another method was proposed by Dr. Dana of Lowell, United States, 
 for ascertaining the real value of commercial indigo. He directs that 10 
 grains of indigo, reduced to a very fine powder, be put into a small glass 
 flask, with two and a half ounces, by measure, of a solution of carbonate 
 of soda, of from 30° to 35 Q of strength by Twaddell’s hydrometer ; after 
 boiling for a few minutes, 8 grains of crystals of chloride of tin are to be 
 added, and the whole boiled for half an hour. By this means the indigo is 
 dissolved, and the liquor appears of a yellow colour. Six grains of bichro- 
 mate of potash (red chrome) are dissolved in 6 ounces of water ; and this 
 solution of chrome is added, which precipitates the indigo blue, along 
 with a trace of the indigo red, leaving the other ingredients in solution. 
 The whole is next to be poured upon a weighed filter (keeping in reserve 
 another filter of the same weight), and the precipitate washed with 1 ounce 
 of muriatic acid diluted with 3 ounces of boiling water, and afterwards with 
 hot water, till nothing but water passes through. Then dry, and weigh 
 the filter, and make a note of the weight of the precipitate ; burn one filter 
 paper against the other, and their difference in weight is the quantity of 
 silica contained in the indigo. This, deducted from the weight of the 
 precipitate, gives the quantity of pure indigo. The late Mr. Walter Crum, 
 who communicated the above to the British Association in 1841, added 
 that carbonate of soda with protoxide of tin dissolves indigo, and forms a 
 yellow solution, but so slowly, that he doubts if all the 10 grains are acted 
 upon. He thinks Dr. Dana must mean soda-ash, which contains a notable 
 quantity of caustic soda, but a much weaker solution of caustic soda would 
 answer the purpose. 
 
 Pure indigo, besides its great importance as a dye-drug, possesses 
 some most important and interesting chemical properties, but which are 
 as yet not very well understood. Some of these we shall notice before 
 entering upon its practical value. If pure indigo be heated to about 550° 
 Fah. it sublimes, producing a beautiful transparent vapour of a reddish- 
 violet colour, which adheres to the sides of the vessel in which it is sub- 
 limed, or on the top of the cinder left, in long needle-shaped crystals. 
 Mr. Crum, whose investigations have thrown great light upon the chemical 
 nature and properties of indigo, employed for its sublimation the covers of 
 two platinum crucibles, about three inches diameter, and of such a form 
 that, when placed with their concave sides inwards, they were about three- 
 eighths of an inch distant in the middle. About the centre of the lower lid 
 were placed spread thinly about 10 grains of indigo, precipitated from the 
 
INDIGO. 
 
 237 
 
 dyer’s vat, in small lumps, about a grain each ; then, having put on the 
 cover, the flame of a spirit lamp was applied beneath the cover containing 
 the indigo. The indigo immediately began to melt with a hissing noise, 
 which, when it had nearly ceased, the lamp was withdrawn, and the whole 
 allowed to cool. On removing the cover, the sublimed indigo was found 
 planted on its inner surface, and a little remained upon the charred matter, 
 and was easily removed. In this way he obtained from 18 to 20 per cent, 
 of the indigo employed. 
 
 As few working men have access to platinum crucible covers to repeat 
 this experiment, we may state, that it may be successfully repeated by 
 taking a thin porcelain plate, or a sheet of iron or copper, with the indigo 
 placed upon it, and covering it with a pretty large watch-glass ; when that 
 part of the plate under the indigo is heated by a lamp, the vapours very 
 soon make their appearance; and towards the close the glass appears 
 black, owing to the coating of indigo which adheres to its inner surface. 
 To obtain pure indigo for experiment, the easiest method is to take a little 
 of the yellow solution of the indigo vat. On adding to this a few drops of 
 muriatic acid, to combine with the lime, the blue indigo falls to the bottom, 
 and can be readily collected upon a filter, then washed and dried. 
 
 Another method has been described by T. Taylor, Esq., which is as 
 follows : — “ Any quantity of indigo is to be reduced to powder, and mixed 
 with about half its weight of plaster of Paris. To these materials so much 
 water is to be added as will bring the whole to a thin paste. This is to.be 
 spread evenly upon an iron plate to the depth of the eighth of an inch, and 
 allowed to remain exposed to the air, or to a gentle heat, until it is toler- 
 ably dry. If the heat of a large spirit-lamp be now applied to the under 
 surface of the plate, the indigo begins to smoke, emits a disgusting odour, 
 and in a few minutes is covered over with a dense purple-red vapour, 
 which condenses into brilliant flattened prisms, or plates of an intense 
 copper colour, forming a thick velvety coating over the surface imme- 
 diately exposed to heat. When this ceases to appear, the heat is of course 
 to be withdrawn; and when cold, the sublimed crystals may be readily 
 lifted or swept off, without in the slightest disturbing the subjacent mass. 
 The operation is exceedingly beautiful to look at, is effected in a few 
 minutes, and any quantity of materials might be acted upon. For ultimate 
 analysis, the sublimed indigo must be previously washed with alcohol or 
 ether.” 
 
 We have tried this and most of the other experiments repeatedly, but 
 the results were not favourable for such processes being of practical value 
 in the dye-house as a test for the value of indigo. 
 
 A method of much easier practice in the dye-house than any of those 
 given, was proposed by Henry Schlumberger : — 
 
 “ This test consists in dissolving the indigo in fuming sulphuric acid, 
 and decolourising the solution, which has been diluted with much water, 
 by means of chloride of lime. As this acts only on the blue-colouring 
 substance, and not at the same time on the various other bodies which 
 
238 
 
 INDIGO. 
 
 indigo contains, the quantity of chloride of lime requisite to produce 
 decolourisation agrees with the amount of colouring matter. 
 
 “ The operations in this experiment are as follows: — I prepare, in the 
 first place, a portion of pure indigo or indigo blue by removing the scum 
 which is continually formed on the blue vat, treating it with an excess of 
 dilute hydrochloric acid, washing the deposit until all soluble parts have 
 been removed, then drying it and preserving the indigo in well-closed 
 bottles, in order to protect it from all changes in the moist state. In all 
 my experiments this pure indigo serves as a standard, and for com- 
 parison with the results which the various kinds of indigo submitted to 
 the test afford. Suppose the quantity of colouring matter in the pure 
 indigo to be 100°, I express the value of the tested indigo by numbers 
 which indicate the percentage of pure colouring matter. In each experi- 
 ment I employ the standard indigo for comparison with that of commerce, 
 as it is then not requisite to determine previously the amount of chloride 
 of lime in solution; besides which, the experiment is more accurate. In 
 this case the causes of the differences in the results depend on cir- 
 cumstances, which always remain the same whether the standard indigo 
 is employed, or the indigo the degree of purity of which is to be 
 ascertained. Twenty grains of each kind of indigo is weighed off, 
 which must be pulverised and finely ground; half an ounce of fuming 
 sulphuric acid is added, and the mixture is now rubbed together, the 
 dish containing it being placed for four hours at a temperature of from 
 122° to 140°. 
 
 Meantime as many glasses, containing about a quart, are filled with 
 distilled water as there are sulphate solutions, and to each solution of 
 indigo is added its equal volume of water from the glass. The liquid 
 becomes warm, upon which they are rubbed again; water is then gradu- 
 ally added until the dish is full, when the whole is poured into the 
 glass, and the dish washed with a portion of the water. Hereupon a 
 solution of chloride of lime is prepared of 2° Twad. in strength, and a 
 given quantity taken, say ten graduations of an alkalimeter. 
 
 “ The well-stirred blue solution of the sulphate of indigo is now 
 measured in an alkalimeter," a tube divided into 100°, and a portion 
 poured into a dish, well stirred, and the entire quantity of the chloride 
 of Hme contained in the measure added at once. If the liquid imme- 
 diately assumes a yellow colour, it is a sign of an excess of chloride of 
 lime, and now sulphate of indigo is added by degrees until a faint olive- 
 green colouring has been obtained. The experiment is now repeated, 
 and the quantity of chloride of lime which had been found necessary in 
 the first case, added to the quantity of sulphate of indigo ; so that with 
 one single mixing, there being neither an excess of chloride of lime nor 
 of sulphate of indigo, the liquid acquires that tint at once. But when 
 after the first mixture the liquid has retained a blue colour, which is a 
 sign of an excess of the sulphate of indigo, fewer degrees of it are 
 taken, until the requisite tint has likewise been attained with a single mixing. 
 
INDIGO. 
 
 239 
 
 “ When the several indigoes have been treated in this manner, the 
 following calculation is made to obtain the true value of the indigo 
 which has been examined; the goodness of the indigo is in inverse ratio 
 to the quantity of sulphate of indigo employed in decolourising. 
 
 “ Suppose, for instance, it were found that pure indigo required 54 
 parts of its sulphate solution to be decolourised by the fixed quantity 
 of chloride of lime, and that, on the other hand, the indigo under ex- 
 amination required 64 parts of its sulphate solution, then according to the 
 proportion — 
 
 64 ; 54 = 100 : a?, --- =ar, or equal to 84*5, 
 
 which indicates the quantity of indigo blue contained in 100 parts of the 
 indigo examined. 
 
 “It is important for the accuracy of the experiment that the pure 
 indigo, and the kinds of indigo submitted to the test, should be equally 
 moist, and it is therefore requisite to enclose* all the samples as soon as 
 they are taken out of the chests in glass phials, to prevent any attraction 
 of moisture or desiccation previous to weighing. When a chest contains 
 several kinds of indigo which exhibit slight differences in their tints, some 
 pieces are selected which are separated into several lots, these are then 
 powdered together, and the mean result taken as the correct one. But 
 when, as often happens, a chest contains pieces of indigo of entirely 
 different tints, it is best to examine the mixed sorts separately. 
 
 I also dilute the solution both of the sulphate of indigo and of that 
 of the chloride of lime, since the experiment in this manner is less exposed 
 to error than with concentrated solutions. Besides, it is easier when the 
 liquid is only faint blue to distinguish the degree of decolourisation, when 
 it must be discontinued. 
 
 “Impure water, or such as contain salts of lime, produces a more or 
 less considerable precipitate of the blue-colouring substance mixed witli 
 sulphate of mdigo ; it is therefore necessary to employ rain or distilled 
 water. 
 
 “ Tbe last stage of decolourisation, or the point at which it is best to 
 discontinue it, is the more easily ascertained the purer the indigo, and the 
 more complete its solution; and in this case it is evident how sensitive the 
 reaction of the chloride of lime is on the indigo; for a yellow solution of 
 indigo, to which chloride of lime has been added, in which, therefore, 
 there is an excess of chloride of lime, is rendered blue by a single degree 
 of the indigo solution, a proof that this method will indicate a half per 
 cent. In the commercial kinds of indigo it is less easy to fix the point at 
 which decolourisation must be discontinued, for in this case the de- 
 colourised liquid assumes an olive colour, and from 2° to 3° of the indigo 
 solution must be added to change the yellow colour into the blue. 
 
 “I have preferred the method of taking a fixed quantity of the chloride 
 of lime and varying that of the sulphate of indigo, to that of making the 
 
240 
 
 INDIGO. 
 
 sulphate of indigo a fixed quantity, and allowing the decolourising agent 
 to be diminished or increased, from its being possible to dilute the indigo 
 solution with much water, which has the advantage of rendering the 
 degrees greater.” 
 
 Another method, and of much easier practice in the dye-house, is thus 
 given by M. Reinsch : — 
 
 Reinsch tried various modes of determining the quality of indigo — 
 such as the external appearance, the intensity of colour imparted to yarn 
 by the cold vat, the quantity of indigo blue obtained by sublimation, the 
 quantity of indigo blue deposited from the cold vat, and the specific 
 weight. Not one of these methods, however, gave results to be relied on. 
 
 “ At last,” he says, “ I resorted to fuming sulphuric acid, and obtained 
 the most satisfactory results. It is necessary, however, that the indigo 
 should be pounded very fine, and the acid should be as concentrated as 
 possible. I must also observe, that the solution of the Java indigo, and 
 of that indigo which I prepared in a chemical way, by treating it with 
 acid, caustic potash, spirit of wine and water, did not possess that pure 
 blue colour like that of the Bengal sort, although I repeated the experi- 
 ments several times, and could not, therefore, determine anything with 
 regard to the purified indigo. A dyer of great experience informed me, 
 that for solution in sulphuric acid he prefers Bengal to the Java sort, as 
 the latter is burnt by the acid, which is always the case when the indigo 
 does not dissolve with a pure blue colour, but assumes a crimson hue on 
 the sulphuric solution being poured in water. 
 
 “ The mode in which I proceed is as follows: — 2 grains of each sample 
 of indigo are well pounded, mixed with four or five drops of fuming 
 sulphuric acid, and rubbed with it until the whole forms a brown uniform 
 mass. To this 15 grains of sulphuric acid are added, and triturated till it 
 produces a clear green solution, whereupon other 15 grains of fuming 
 sulphuric acid are added; lastly, this solution is gradually mixed with 
 150 grains of water. Two glass cylinders of equal length and width are 
 now divided each into twenty equal parts, and 15 grains of the sulphuric 
 solution (which is best measured by a glass tube closed at one end) 
 poured into one and mixed with water, till the solution is of a light- 
 blue colour and transparent; if 15 grains of the solution do not produce 
 sufficient colouration, a small quantity more of it is added till the cylinder 
 is filled with the light-blue solution. I generally commence with the ap- 
 parently best indigo. After this the second cylinder is filled in the same 
 way with an equal quantity of sulphuric solution of the same indigo 
 sample and water, in order to see whether the two solutions are equal in 
 colour. If this be the case, one of the cylinders is emptied, and an equal 
 quantity of sulphuric solution of an inferior sample poured into it and 
 gradually diluted with water, till the solutions in both cylinders are per- 
 fectly alike in colour. Care is to be taken that the colouration be not 
 too intense nor too light, it being in either case difficult to obtain both 
 solutions of the same hue. For discovering this equality the eye will also 
 
INDIGO. 
 
 241 
 
 be much assisted if the relative position of the cylinders is changed from 
 the right to the left, or by placing them alternately before or behind one 
 another. As soon as the colour of both is thus found to be equal, the 
 quantity of water is examined which has been poured into the second 
 cylinder. Supposing now that 15 grains of sulphuric solution have been 
 employed in either of the cylinders, but the quantity of water which 
 produced the equal colour was in the first or standard cylinder 20 parts, 
 and m the second only 15 parts, then the sample of which the latter 
 solution was made will contain five-twentieths or one quarter less of 
 colouring matter. 
 
 “This method is so easy and convenient, that everybody can avail 
 himself of it. All that is required is to keep ready a certain quantity of 
 indigo solution of a known quality as standard solution, and then to 
 prepare a sulphuric solution of the indigo to be tested. 
 
 The above described method may even be made more accurate if 
 longer glass cylinders are used, so that the percentage quantities may be 
 indicated. The glasses must then be divided in 100 parts. The larger the 
 degrees are, the more accurate will the results be. 
 
 “ I have yet to add some observations with regard to an adulteration 
 practised on the indigo, and which is of importance to the druggist. Each 
 large indigo-chest contains a quantity of dust, which is said to amount 
 sometimes to 8 or 10 pounds. This dust is an artificial product, composed 
 of starch or white lead and powdered indigo, and is put in the chest in 
 order to increase its weight.” 
 
 In testing by this method we think it better, instead of putting the 
 indigo into a dish with vitriol and rubbing it, to take 2 grains of each sample 
 well ground, put them into small bottles well stoppered with i ounce 
 vitriol at 169° Twad., free from nitric acid, in each, and allow them to stand 
 for twelve hours, shaking them occasionally, then proceed as stated by 
 Keinsch. Bad and adulterated indigo sometimes gives a greenish blue, 
 and interferes with this comparison, and should be rejected or valued 
 accordingly. 
 
 Another process of testing the value of indigo has been recommended 
 7 B ° lley ’ de P endm g upon the decolourising by chlorine, and by a 
 
 method which ensures the constancy of the chlorine; this is done by using 
 y rochlonc acid and chlorate of potash. A given quantity of pure 
 indigo, say 100 grains, is converted into sulphate of indigo by adding 
 to the 100 grains about 2^ ounces of the strongest sulphuric acid, and 
 allowing it to stand for six or eight hours. The whole is now put into 
 an evaporating basin or flask, with about one pint of water, and one 
 quarter of an ounce, by measure, of hydrochloric acid, and brought to 
 boil. A solution of chlorate of potash is now made in 100 measures of 
 water by alkalimeter, which is added to the indigo solution by degrees 
 until the blue liquor passes into green, brownish-green, and lastly into 
 red, when the operation is finished. A little experience will shew the exact 
 time to stop. The amount of chlorate solution taken to effect this is 
 
 Q 
 
242 
 
 INDIGO, 
 
 noted, say it took 50 graduations, then each graduation taken is equal 
 to 2 grains of indigo, or by doubling the water of the chlorate then 
 one graduation of the chlorate will be equal to 1 grain of pure indigo ; 
 such a standard solution being made, the relative value of indigoes will 
 be easily ascertained. 
 
 Still another method of testing the value of indigo was recommended 
 by the late Dr. Penney of the Andersonian University, Glasgow, based upon 
 the circumstance that indigo blue, in presence of hydrochloric acid, is 
 decolourised by bichromate of potash. Ten grains of the sample, in very 
 fine powder, are dissolved in 2 drachms, by measure, of fuming sulphuric 
 acid. After standing several hours, to ensure complete solution, it is 
 diluted with a pint of water, and the whole well stirred, after which there 
 is added f of an ounce, by measure, of hydrochloric acid. Seven and a 
 half grains of dry and pure bichromate of potash are now dissolved in 
 water, and the solution made up to 100 measures of an alkalimeter; this 
 is added drop by drop to the sulphate of indigo, until the blue colour 
 disappears, and the colour of a drop of the solution put on a white plate 
 or paper is found to be orange-brown, having no green or blue tint. 
 The number of graduations required to effect this is noted. Dr. Penney 
 found that 7\ grains bichromate of potash were equal to 10 grains pure 
 indigo, so that every ten graduations of the solution taken to decolour the 
 sulphate are equal to 1 grain of pure indigo, or one graduation to a per 
 cent, of indigo. 
 
 Indigoes of Commerce . — The indigoes of commerce have been described 
 in a very able manner by M. Chevreul. The following ^details are extracted 
 from his work: — “ They are sometimes in small, light pieces, of a violet- 
 brown colour, and sometimes in cubical loaves.. These loaves may be 
 considered good when they assume a copper-coloured aspect on friction 
 with any hard and smooth body; when there are no cavities found in 
 their interior presenting a series of brown or whitish-coloured streaks ; 
 and lastly, when they are free from fissures externally. If they are of a 
 blue instead of a violet colour, it is a proof that they^contain more or less 
 of the yellow matter. The presence of this matter in large proportions 
 tends, by its admixture, to convert the blueinto a green, and also neutralises 
 the colour of the red matter of indigo. An obscure dark brown or dirty- 
 green colour indicates, in general, that the indigoes have undergone some 
 deterioration in their preparation or during their transport. Indigo is 
 destitute of odour, provided it has undergone no alteration by heat and 
 moisture. Indigoes are classified into different kinds, according to the 
 country in which they are prepared, or according to their colour. 
 
 “ First. Indigoes prepared in Asia : they are from Bengal, Coromandel, 
 Madras, Manilla, and Java: — 
 
 “ Bengal Indigoes. — The trade in this indigo is chiefly carried on 
 in Calcutta, and through the medium of the East India Company; its 
 varieties are very numerous. The principal, commencing with those of the 
 best quality, are — 1. The superfine or light blue. This is in a cubical 
 
INDIGO. 
 
 243 
 
 form, light and friable, soft to the touch, of a clean fracture, and giving a 
 beautiful copper colour on being rubbed with the nail. 2. Superfine 
 violet. 3. Superfine purple. 4. Fine violet, in colour a little less brilliant 
 than the superfine, and rather heavier. 5. Fine purple violet. 6. Good 
 violet, somewhat heavier than the fine violet. 7. Violet red. 8. Common 
 violet. 9. Fine and good red, heavier than the preceding, colour border- 
 ing decidedly on red. 10. Good red, of a firmer and more compact 
 structure. 11. Fine copper-coloured, redder and more compact still. 
 12. Middling copper-coloured. 13. Ordinary and low copper-coloured: 
 this is of a copper-coloured blue or red, somewhat difficult to break. 
 
 “ Coromandel. — Those of the best quality correspond to the middling 
 Bengal indigoes, and are met with in square masses, having an even 
 fracture, but are more difficult to break. The inferior indigoes are heavy, 
 of a sandy feel, having a blue colour bordering on green or grey, or even 
 black — often in very large squares, and covered with a slight crust or rind 
 of a greenish-grey colour. These are the most difficult to break of all the 
 indigoes of commerce. 
 
 “ Madras. — They have a grained rough fracture, and are of a cubical 
 figure. The superior qualities have no rind; in figure they somewhat 
 resemble a hat , and are more light and friable than those of Coromandel. 
 These indigoes, when of the best quality, have great lightness, but are not 
 equal to the superfine blue of Bengal. The middling qualities have a very 
 slight copper colour. The colour of the inferior qualities is a dark or 
 muddy blue, black, or even grey, and greenish. 
 
 “ Manilla. — These present the mark of the rushes upon which they 
 have been dried. They are of a .finer consistence and lighter colour than 
 are the indigoes of Madras, but not so fine as the indigoes of Bengal. The 
 better qualities are often in flat and elongated masses, somewhat porous, 
 and consequently light. The middling qualities are of a violet colour, but 
 they are inferior to the violet ,of Bengal. 
 
 “ Java. — In flat, square masses, sometimes of a lozenge shape. The 
 superior qualities appear to the sight as fine as the blue, violet, or red 
 indigoes of Bengal; but they are not so in reality. 
 
 “ Second. Indigoes prepared in Africa. They are from Egypt and 
 Senegal : — 
 
 “ Egypt. — The superior qualities of Egyptian indigo are superfine and 
 fine violet blues. They are light, but their structure is not very fine, and 
 they often contain sand. The squares are rather .flatter than those of 
 Bengal. 
 
 “ Senegal. — They are of good quality, .but they contain more earthy 
 matter than any other indigoes in the trade. 
 
 “Third. Indigoes from America; those of Guatemala, Caraccas, 
 Mexico, Brazil, Carolina, and the Antilles : — 
 
 “ The indigoes of Guatemala , of the Caraccas , and of Mexico , are of 
 various kinds. The best are of a bright blue colour, remarkably light and 
 fine. These indigoes are esteemed equal to the best Bengal. The inferior 
 
244 
 
 INDIGO. 
 
 qualities are of a violet colour, but in general are more mixed than the 
 Bengal kinds. 
 
 “ Brazil . — These indigoes are in small rectangular parallelopiped 
 masses, or in irregular lumps, of a greenish -grey colour externally, and 
 having a smooth fracture, a firm consistence, and a copper-coloured tint of 
 greater or less brilliancy. 
 
 “ Carolina . — In small square masses, having a grey exterior. The 
 best qualities have a dull copper colour, bordering on violet or blue. The 
 common qualities are almost always of a greenish-blue ; they are rarely 
 found of a copper colour. 
 
 “ The principal varieties of indigo in commerce are the Bengal, the 
 Caraccas, the Guatemala, the Madras, and the Manilla. 
 
 “Besides the numerous shades already described, we should also be 
 on our guard against certain defects, of greater or less consequence, and 
 which depend on causes acting either on the indigo when already prepared, 
 or else occurring during its preparation. The following are some of the 
 characters to be borne in mind: — The large or small fracture : squares of 
 indigo reduced, by accident, into lumps of variable size. Fragment : 
 squares reduced into irregular pieces, and fine enough to be passed 
 through a sieve. Sometimes, also, we meet with squares which are readily 
 broken, and which present a whitish kind of mouldiness in their interior ; 
 gritty lumps, throughout which are points presenting the appearance of 
 granite ; streaky masses, in which are layers of various shades of blue, placed 
 one above the other, in the same square; pieces of a scorched appearance, 
 which, on being sharply rubbed between the hands, are ground into small 
 fragments, nearly black in colour ; sandy lumps, in the interior of which 
 the eye can detect shining specks, which are nothing more than sand.” 
 
 Pure indigo, whether obtained by sublimation, or other chemical 
 means, is of a deep blue, approaching to violet. If scratched or rubbed, 
 it has a strong copper hue, and a metallic lustre. It has neither taste nor 
 smell, and is remarkable for its neutral properties. It is insoluble in water, 
 alcohol, ether, alkalies, and dilute acids. Strong sulphuric acid dissolves 
 indigo readily, and forms with it a purple-blue solution. Its chemical 
 composition is, according to the late Mr. Crum and M. Dumas, — 
 
 Crum. 
 
 8 Carbon. 
 
 5 Hydrogen. 
 1 Oxygen. 
 
 1 Nitrogen. 
 
 Dumas, who doubled the atoms. 
 
 16 Carbon. 
 
 10 Hydrogen. 
 
 2 Oxygen. 
 
 2 Nitrogen. 
 
 The chemical qualities, and some reactions of indigo, have been exten- 
 sively studied. If blue indigo be brought into contact with substances 
 having a strong attraction for oxygen and in the presence of an alkali, 
 the indigo is said to be reduced to the white state, and becomes soluble in 
 the alkali ; this, as is well known, is the principle of the blue vat. The 
 following matters all reduce blue indigo to white : — 
 
INDIGO. 
 
 245 
 
 Protoxide of tin, 
 Protoxide of iron, 
 Sulphide of arsenic, 
 Phosphorus, 
 
 The phosphites, 
 Sulphites, 
 
 Sulphide of potassium, 
 Sulphide of sodium, 
 Sulphide of calcium, 
 Sugar, 
 
 Starch, 
 
 Tannin. 
 
 Substances which yield oxygen, such as oxide of copper, turn white 
 indigo to blue, and the copper is reduced to the suboxide. Water con- 
 taining carbonic acid also oxidises white indigo. Indigo white is a crys- 
 talline solid, having a fibrous silky lustre, tasteless, without smell, and 
 heavier than water ; it is insoluble in water, but soluble in alcohol and ether. 
 
 When well dried it may be kept in the air for several days without 
 change, but if moist it soon becomes blue; when heated it becomes 
 purplish-blue. White indigo was long thought to be blue indigo with 
 less oxygen, and was sometimes called deoxidised indigo ; but chemists 
 now consider it as blue indigo, with an equivalent more of hydrogen : 
 Thus we have — 
 
 Blue. 
 
 White. 
 
 Carbon, . 
 Nitrogen, . 
 Hydrogen, 
 Oxygen, . 
 
 Carbon, 
 Nitrogen, . 
 Hydrogen, 
 Oxygen, . 
 
 Dumas supports his view by reference to many vegetable organic sub- 
 stances which comport themselves in a similar manner, and gives the formulae 
 of a few compounds, which by analogy he connects with indigo, and shews 
 that there may be not only a relation, but that by the mere addition or 
 subtraction of one equivalent of an element, such as hydrogen, two bodies 
 may differ as much in their properties as does blue indigo from white. 
 
 The late Baron Liebig’s view of the reactions of indigo and its rela- 
 tions to other bodies differs from that of Dumas. He considers, from the 
 result of careful and extensive investigation, that indigo contains a salt 
 radical (page 27) which he termed anyle , and which is composed of C 8 H 6 N. 
 This, in a sense, is indigo without any oxygen. He then considered 
 that white indigo is the hydrated protoxide of this base or radical, and 
 that blue indigo is the peroxide. Thus — 
 
 Anyle, 
 
 White indigo, 
 Blue indigo, 
 
 C. H. N. Q. Water. 
 
 8 5 10 0 
 
 8 5 111 
 
 8 5 12 0 
 
 This view of the matter was not inconsistent with facts and practical 
 observations in the dye-house, and can be supported by analogies 
 in the same manner as the other view. Indeed, most of the colouring 
 principles of vegetables exist in the plants as colourless bases, and become 
 coloured by the absorption of oxygen. 
 
 M. Pressier, who has been very fortunate in his researches into vege- 
 table colouring matters and bases, favours Liebig’s view, from the fact that 
 
246 
 
 INDIGO. 
 
 blue indigo, sugar, and potash react together, and form white indigo. He 
 therefore considers it very improbable that indigo should extract hydrogen 
 from water, at the same time that the oxygen of the water would combine 
 with the hydrogen of the sugar to reproduce water. Dumas, however, 
 observes upon this, that there is no necessity for supposing water to be 
 decomposed, as the hydrogen of the sugar may combine directly with the 
 indigo blue and form indigo white. These views of the question shew 
 that the subject is full of interest, and ought to stimulate the dyer to study 
 his trade as a science, which might lead him to the solution of some of those 
 vexed questions of chemical science. The present prevailing idea of the 
 constitution of indigo and its relations to other bodies is, that indigo 
 contains a definite colouring material termed indigotin , from which numer- 
 ous derivatives belonging to the indigo series have been prepared. The 
 following are the most important of the immediate compounds derived 
 from or related to indigo, premising that indigo blue or indigotin is termed 
 in the series indyl : — 
 
 Indigo blue, 
 White indigo, 
 Isatin, 
 
 Isatic acid, 
 Isathyd, 
 Indin, 
 Hydrindin, 
 
 Symbol. 
 
 . C 8 H 5 NO = Indyl symol, . . In 
 
 . C 8 H 6 NO *= Indyl hydride, . . InH 
 
 . C 8 H 5 N0 2 = Indyl oxide, . . InO 
 
 HC 8 H 6 N0 3 = .... HInHOj 
 
 . C 8 H 6 N0 2 = Indyl hydrate, . InHO 
 C 16 H 10 N 2 O 2 = Polymeride of indyl, In 2 
 Ci 6 H 11 lSr 2 0 2 = Indin hydride, . 2InH 
 
 It will be observed here that the compound indin is exactly that given by 
 Dumas as the composition of indigo blue. It is simply doubling the 
 equivalents given by Crum; but hydrindin contains an equivalent of 
 hydrogen less than a double equivalent of white indigo. 
 
 If indigo be thrown into fused hydrate of potash, its blue colour 
 disappears ; it dissolves, and is partly decomposed along with the water of 
 the alkaline hydrate ; hydrogen and ammoniacal gases are evolved, while 
 carbonic acid and another acid, having properties similar to acetic acid, are 
 formed, and combine with the potash. By digesting this mixture with a little 
 sulphuric acid, the alkali combines with it, and the acids may be obtained. 
 
 If indigo, in fine powder, be added to nitric acid, diluted with seven 
 or eight times its weight of water, and a gentle heat be applied, it dissolves 
 with effervescence, forming a yellow liquid. After standing a little, this 
 liquid may be decanted from any resinous matter formed during the 
 process, and concentrated by evaporation, and speedily there will be found 
 deposited a quantity of yellowish-white crystals, having a sourish -bitter 
 taste, and requiring about 100 parts of cold water for their solution. This 
 was formerly termed indigotic acid, but is now called anilic acid, from the 
 species and name of one of the plants which yields indigo. It combines 
 with all known bases, forming salts, which have generally a yellow colour. 
 It gives a blood-red colour to solutions of the persalts of iron. 
 
 If indigo be added to strong nitric acid, and heat be applied, it quickly 
 
INDIGO. 
 
 247 
 
 dissolves, evolving a great quantity of nitrous gas. On allowing the liquid 
 to cool, a large quantity of semi-transparent yellow crystals are formed, 
 having a very bitter taste. This is called carbazotic or picric acid. 
 
 To procure it in a purer state, the crystals obtained by the above 
 operation are to be washed in cold water, and then boiled in water suffi- 
 cient to dissolve them. On filtering the liquid and allowing it to cool, 
 the acid again crystallises in brilliant yellow prisms. The acid may also 
 be obtained by the action of nitric acid upon anilic acid. 
 
 Picric acid is very permanent in its constitution. When fused in 
 chlorine or with iodine, it is not decomposed, nor does a solution of 
 chlorine affect it. Cold sulphuric acid has no action upon it, but dissolves 
 it when hot. Boiling hydrochloric acid does not act upon it, and nitro- 
 muriatic acid (aqua regia') dissolves it with difficulty. It acts like a strong 
 acid upon metallic oxides, dissolving them, and forming peculiar crystallis- 
 able salts. These are yellow ; they detonate strongly when sharply heated, 
 and also by percussion, particularly the salt formed with potash. When a 
 little of it is gradually heated in a glass tube, it first fuses, and then sud- 
 denly explodes, breaking the tube to pieces. Care is necessary in making 
 this experiment, as the fragments of glass may injure the face. 
 
 This acid is an excellent test for the presence of potash in any fluid. A 
 solution of it in alcohol produces a bright yellow crystalline precipitate, 
 even in a diluted solution of the alkali. It is thus more sensible than the 
 chloride of platinum, commonly employed for the detection of potash, for 
 that re-agent does not produce a precipitate in dilute solutions. Picric acid 
 has strong tinctorial properties, and has been long used as a dye for silk 
 and woollen, to which it imparts a beautiful rich yellow when mordanted 
 with alum or tartar. 
 
 When indigo is acted upon by very dilute fuming nitric acid, it 
 unites with two atoms more of oxygen, and is consequently converted into 
 isatine. This substance, under the influence of alkalies, absorbs one equiva- 
 lent more of water, and assumes an acid character, and is termed isatinic 
 acid. This acid combines with other substances, forming a series of inter- 
 esting compounds. 
 
 Chromic acid has a similar action upon indigo as nitric acid. 
 
 When indigo in the dry state is brought into contact with dry chlorine, 
 no chemical action is observed ; but when indigo, suspended in water, is 
 subjected to the action of chlorine, it becomes brown, and several new pro- 
 ducts are formed. In addition to muriate of ammonia and formic acid, there 
 are several distinct chlorinated compounds formed, termed chlorisatin, di- 
 chlorisatin , trichloraniline , trichlorophinic acid, and chloranil. Chlorisatin forms 
 in red crystals of a bitter taste ; when dissolved in a solution of caustic 
 potash they produce a red colour. The salts of lead give with this solution a 
 yellow precipitate, which becomes a fine scarlet on standing. The salts of 
 copper (blue-stone), &c., give a brown, which becomes blood-red by 
 exposure to the air. Bichlorisatin has properties analogous to those of 
 chlorisatin ; its solution in potash gives a yellow precipitate with the salts 
 
24S 
 
 INDIGO. 
 
 of lead, but does not alter by exposure to the air ; and with the copper 
 salts it gives a yellowish-brown, which passes to blood red. Chloranile 
 crystallises in scales of a brass -yellow colour, and when dissolved in potash 
 gives a beautiful purple colour. 
 
 If indigo in powder be added to a solution of caustic potash of specific 
 gravity 1*35 (70 Twaddell) and boiled, an orange-yellow salt is formed. 
 The solution of the boiled mass becomes blue in the air from absorption 
 of oxygen (like a solution of white indigo), and blue indigo precipitates. 
 
 Besides the compounds resulting from the action of nitric acid and 
 chlorine upon indigo, there are several others which, from their true char- 
 acters being still doubtful, we have not thought it necessary to enumerate. 
 Some practical dyer may indeed be inclined to ask, what those already 
 noticed have to do with dyeing ? We are sorry that, with respect to some 
 of them, we cannot give any satisfactory answer to the question ; but the 
 same question was asked when chemists first intimated that chromic acid 
 produced yellow salts when combined with lead, yet this simple hint has 
 completely revolutionised various departments of dyeing ; and the action 
 of chromic acid upon indigo, as already observed, has been both a source 
 of annoyance and advantage to the dyer. Previous to the use -of alkaline 
 solutions of lead, dyers seldom could get an evenly dyed chrome green upon 
 indigo blue ; the chromic acid being set at liberty acted upon the indigo 
 which was upon the goods, destroying in part the blue colour, after which 
 the green was all light-yellow Mains. But now this same action of chromic 
 acid upon indigo has been taken advantage of by calico-printers when 
 they want a white pattern on a blue ground. 
 
 Previous to the introduction of bichromate of potash for this purpose, 
 the calico-printers were, to a certain extent, limited in their operations. 
 Thus — 
 
 The pattern was printed upon the cloth with the oxide of a metal, such 
 as copper and zinc, which yield their oxygen easily to other substances ; the 
 goods were afterwards dyed blue by passing them through the vat ; but 
 the parts upon which these metallic salts were printed resisted the dye, by 
 yielding their oxygen to the indigo — a process which will afterwards be 
 described, so that the piece when finished had a blue ground with a white 
 pattern. But after the blue vats had been wrought for some time, they 
 could not be used for this purpose, owing to the weakness of the dye, and 
 the consequent length of time necessary to produce the required shade. 
 So that these resist pastes were in a manner washed off, and the pattern 
 spoiled. Now, in place of -throwing out as useless vats not exhausted of 
 their indigo, as was formerly done, the cloth is dyed blue without resists, 
 and after being slightly scoured and washed, it is passed through a strong 
 solution of chromate of potash, and dried in the shade ; the required 
 pattern is then printed on the cloth with a mixture of oxalic and tartaric 
 acids made into a paste with gum or clay. The potash in union with the 
 chromic acid is taken up by these acids, and the chromic acid being set at 
 liberty acts on the indigo, and a white pattern is produced. 
 
SULPHATE OF INDIGO. 
 
 249 
 
 V‘ 
 
 The following table exhibits the composition of those substances wWch 
 we have briefly described as resulting from the action of nitric acid and. 
 chlorine upon indigo. It may be required for reference: — 
 
 Name. 
 
 Indigo, .... 
 Isatin, .... 
 Anilic, or indigotic acid, 
 Picric, or carbazotic acid, 
 Chlorisatin, . 
 Bichlorisatin, 
 Trichloranilj 
 Chloranil, 
 
 C. H. O. N. CL 
 
 8 5 110 
 
 8 5 2 1 0 
 
 7 5 5 1 0 
 
 6 3 5 1 0 
 
 8 4 2 1 1 
 
 8 3 2 1 2 
 
 6 4 0 1 3 
 
 6 0 2 0 4 
 
 The only substance which dissolves indigo, without destroying its 
 colour and composition, is highly concentrated sulphuric acid. For this 
 purpose the fuming acid of Nordhausen is preferable (page 77) ; acid made 
 from brimstone, concentrated to 169° Twaddell, is what is universally used 
 in this country. The substance formed is popularly known by the names 
 of sulphate of indigo, Saxon blue, China blue, and extract of indigo. The 
 action of sulphuric acid upon indigo is found to be something more than a 
 mere solution : a chemical combination, in definite proportions, results, 
 forming two distinct substances, differing considerably from each other in 
 their properties. These two compounds were discovered and described by 
 the late Mr. Crum, and called by him cerulin and phinacin from their colours 
 — the former blue and the latter purple. They have been since named 
 sulph-indylic acid and sulpho-purpuric acid. The former, which consti- 
 tutes the blue principle of Saxon blue, is formed most abundantly when 
 the sulphuric acid is sufficiently strong and abundant, and other proper 
 means attended to. Its composition is found to be one atom of indigo 
 combined with two of sulphuric acid. The other is the principal pro- 
 duct when the indigo preponderates. It is of a purple colour, and 
 when the solution is diluted with water it precipitates. Its composition 
 is found to be equal to one atom indigo to one of sulphuric acid. 
 
 From the nature and properties of these two substances, it is evident 
 that every care should be taken to convert the indigo into sulph-indylic 
 acid, and to avoid the formation of sulpho-purpuric acid. The circum- 
 stances under which this latter acid is formed are — first, too little acid 
 in proportion to the indigo, and, secondly, too little time allowed for 
 digestion. The general proportions used by dyers vary from three to 
 five pounds of acid to the pound of indigo. This is by far too little, 
 and occasions a considerable loss of indigo by the precipitation of the 
 sulpho-purpuric acid when the solution is diluted with water. Close 
 observation shews that it requires from six to eight pounds of concen- 
 trated sulphuric acid to convert a pound of indigo into blue sulph-indylic 
 acid. From some investigations made by M. Dumas, indigo requires 
 even a larger proportion of acid to convert it into sulph-indylic acid. 
 
250 
 
 SULPHATE OF INDIGO. 
 
 He recommends no less than fifteen parts of acid to one of indigo. 
 This quantity, however, we have found to be of no advantage in practice, 
 but rather the opposite, particularly when the acid is to be neutralised 
 before the indigo solution is used, which is the general custom in dyeing 
 cotton. 
 
 We have said that the second circumstance under which sulpho- 
 purpuric acid is formed is that of too short time being given for the indigo 
 and acid to digest. When indigo is first put into the sulphuric acid, there 
 seems to be an immediate solution; but if a drop be spread upon a window 
 pane it appears of a dirty-green colour ; and if allowed to stand for a little 
 upon the glass, a yellowish-coloured liquid begins to run from the blue 
 mass, occasioned, no doubt, by the acid absorbing moisture and separating 
 itself from the indigo, and clearly shewing that the change upon the indigo 
 by the acid is not an immediate one. The more impure the indigo, the 
 darker and greener appears the substance when put upon the glass. After 
 the mixture has stood two or three hours, if tried in the same manner, it 
 appears of a reddish -purple colour. As the liquid stands it begins to 
 assume a violet shade, and finally passes to a deep rich blue. But dyers 
 seldom obtain it in this state: in their hands it generally has a reddish tinge. 
 Mr. Crum found that when the solution is diluted with water, after the 
 colour has become of a bottle-green, the action of the acid is stopped, and 
 sulpho -purpuric acid only is formed. But there are other means by which 
 the action of sulphuric acid upon indigo may be stopped, than by directly 
 diluting the solution with water. As already intimated, it is only the 
 highly concentrated sulphuric acid which converts indigo into sulph- 
 indylic acid. Now, dyers not unfrequently alter the strength of their 
 acid by the process of mixing and preparing their chemic (the technical 
 name for sulphate of indigo). This is very generally done in an open 
 wide-mouthed vessel, which is allowed to stand uncovered, probably in 
 the midst of the steam and vapours of the dye-house ; or, in some cases, 
 the vessel is put into a boiler or tub with boiling water. By these 
 injudicious means the sulphuric acid, which absorbs water very rapidly, 
 is diluted below the necessary strength for the making of sulph-indylic 
 acid, and the result is the formation of sulpho -purpuric acid instead. 
 
 Another cause of the stopping of the action of the acid by dilution is 
 from the indigo. Ground indigc absorbs a quantity of moisture; and if it 
 be not thoroughly dried previous to putting it in the acid, the acid is too 
 much weakened to effect the formation of the substance required. 
 
 There are other causes by which the preparation of chemic is injured. 
 Sometimes the acid and indigo are mixed together at once, and by this 
 means the heat evolved is sufficient to decompose the impurities of the 
 indigo. Part of the acid also suffers decomposition, and a great quantity 
 of sulphurous acid gas is given off ; so much, indeed, that the head cannot 
 be held above the vessel for any length of time without injurious effects. 
 Another practice, for the sake of quickening the operation, is to place the 
 vessel upon the flue in the stove, and keep the solution for hours at a heat 
 
SULPHATE OF INDIGO. 
 
 251 
 
 upwards of 300° Fah. The gas given off in these cases is sometimes so 
 great as to destroy the colours of goods hanging in the stove. Indigo 
 submitted to such treatment is seldom found good ; often its appearance 
 on white paper or glass (which is a general method of testing the quality 
 of sulphate of indigo) is a blackish-green — sometimes a dirty purple — 
 seldom the fine blue violet — scarcely ever the beautiful blue. 
 
 Although the sulpho-purpuric acid is precipitated when water is mixed 
 with the solution of sulphate of indigo, and is insoluble in dilute acids, it is, 
 when freed from the sulphuric acid, soluble in distilled water ; but if any 
 substance be in the water — and common spring water is never pure — it 
 is less soluble. It dissolves in alkalies, and in solutions of the alkaline 
 earths, giving a blue colour of greater or less purity according to the 
 nature of the solvent. 
 
 We have found the following method of preparing sulphate of indigo 
 in quantities for use very satisfactory: — The indigo is reduced to an im- 
 palpable powder, either by grinding in a mortar or a mill, and completely 
 dried, by placing it upon a sandbath or flue for some hours, at a tempera- 
 ture of about 140° or 150° Fah. For each pound of indigo to be used 
 six pounds of highly concentrated sulphuric acid are put into a large 
 jar, or earthen pot, furnished with a cover. This is kept in as dry 
 a place as possible, and the indigo is added gradually in small quan- 
 tities. The vessel is kept closely covered, and care taken that the 
 heat of the solution does not exceed 212° Fah. When the indigo is all 
 added, the vessel is placed in such a situation that the heat may be kept 
 at about 150° Fah., and allowed to stand, stirring occasionally, for forty- 
 eight hours. These precautions being attended to, we have uniformly 
 found that any failure occurring was clearly traceable to impurity of the 
 indigo or weakness of the acid used. 
 
 The dyer now very seldom prepares his own sulphate of indigo ; it is 
 manufactured for him, and sold in the market as indigo extract , which, 
 when properly prepared, is a superior article to that generally prepared by 
 himself. The following is the process of its manufacture : — The indigo is dis- 
 solved in the sulphuric acid as described ; it is then diluted with hot water — 
 distilled water is best; the whole is put upon a filter of woollen cloth, by 
 which means the insoluble impurities of the indigo are separated. The 
 blue solution which has passed through the filter is transferred to a leaden 
 vessel, and evaporated till reduced to about three gallons for every pound 
 of indigo used. There is then added about 4 lbs. of common salt to the 
 pound of indigo, and the whole is well stirred. The sulph-indylic acid 
 is thus precipitated, and the whole is again thrown upon a similar filter of 
 woollen cloth ; the extract remains upon the filter, and when sufficiently 
 drained, is ready for the market. Some makers add a little potash or 
 soda, which may be advantageous, and a little ammonia gives the extract a 
 beautiful bloom. A pound weight of good indigo should yield 14 lbs- 
 of extract. The adulterations in this substance are various. Some of 
 the insoluble matter is occasionally added, or rather not removed, but 
 
252 
 
 SULPHATE OF INDIGO. 
 
 this deteriorates the appearance of the extract. The addition of a little 
 lime or barytes gives an insoluble precipitate, which adds weight to the 
 extract; but all practices of that kind react upon the maker; for 
 although the dyer may not have methods of testing his stuff, he very 
 soons ascertains its working value by experience, and avoids the bad. 
 
 The extract of indigo is used in the dye-house in the same way as the 
 sulphate was used before this method of preparation was adopted. The 
 general term chemic is applied to both, and chemic blue is used in various 
 operations. For dyeing silks and woollens blue, the extract is simply 
 diluted, and the goods merely passed through it ; but this method cannot 
 be adopted with cotton, as its fibres have no affinity for sulphate of indigo. 
 But although not used for dyeing blue upon cotton, it is extensively used 
 for dyeing green upon light goods of that material — for this purpose the 
 chemic is carefully prepared. The extract is put into a cask nearly filled 
 with hot water — the exact quantity is not material, and well stirred ; to this 
 solution a quantity of pounded chalk or whiting is added gradually, until 
 the acid is exactly neutralised ; this is a nice operation, and requires great 
 care on the part of the operator; for, were the acid property to prevail in 
 the least, it would destroy the yellow previously dyed upon the cloth, and 
 a dirty blue would be produced; and were the alkaline matter predominant, 
 it would brown the yellow, and the green would assume a blackish-olive 
 shade. Thus the beauty of the colours depends upon the dyer being 
 careful to stop just at the turning point. The only method employed by 
 dyers for determining the point of neutrality is the taste, and this, from 
 many circumstances which we need not enumerate, is liable to error ; and 
 when the dyer is deceived, the results are very annoying and also expensive. 
 However, the reader may be astonished when we inform him that failures 
 from this source are very few. Were very delicately prepared blue and 
 red litmus-papers used, the results would be much more certain. Some 
 dyers use carbonated alkalies, such as soda and potash, to neutralise their 
 acid ; and no doubt when any of these are used, the sediment at the bottom 
 is much less ; but we have always thought that owing to the salts formed 
 by these alkalies being soluble in the blue solution, the green colour is 
 not so good, especially when quercitron bark is the yellowing substance. 
 
 The process of dyeing greens by this sort of prepared chemic is as 
 follows: — The goods, after being well boiled and washed, are put through 
 a dilute solution of pyrolignite of alumina of specific gravity 1-035 — that is, 
 7 of Twaddell — and washed from this through hot water ; they are then 
 wrought through a decoction of quercitron bark or fustic. When suffi- 
 ciently yellow for the shade of green required, they are then wrought 
 through a quantity of chemic mixed with cold water, wrung from this 
 and dried. If fustic is the yellowing substance used, alum is a better 
 mordant. 
 
 The greatest consumpt of indigo is for dyeing blue by means of the 
 blue vat. We have already mentioned that indigo is insoluble in water ; but 
 if it be by any means deprived of an equivalent of oxygen (or according to 
 
INDIGO BLUE YAT. 
 
 253 
 
 the generally received theory, gets an equivalent of hydrogen), it is soluble 
 in alkalies. It may be said, that according to the law of definite pro- 
 portions described in our first article, it cannot be indigo with an atom 
 less of oxygen. Neither is it; and we see that it has different properties 
 from common indigo, for it is soluble even in weak alkalies, has a power- 
 ful attraction for oxygen, and is a of a white colour. This substance has 
 been termed indigogen , and it may be observed, that the nature of the blue 
 vat depends upon the introduction of substances capable of converting 
 indigo into indigogen. The substances generally used for this conversion 
 are the protoxides of iron and tin, orpiment (sulphide of arsenic), and 
 some organic substances, such as sugar. These last produce the desired effect 
 by their decomposition, such as in the woad vat, where, by the fermentation 
 of the woad and madder, the indigo is converted into indigogen. The 
 indigogen is dissolved by the potash or other alkali put into the vat. 
 
 What is termed the common blue vat, or lime vat, is made up with 
 indigo, lime, and sulphate of iron (copperas). But before describing the 
 nature of this vat, it will be necessary, at the risk of a little repetition, to 
 refer to the properties of oxide of iron (page 129). 
 
 The protoxide of iron, especially when in contact with moisture, has 
 a strong attraction for more oxygen, so as to pass into the peroxide. When 
 the sulphuric acid of copperas is neutralised by an alkali, the iron is left 
 in the state of a protoxide. The blue vat is made up by putting three 
 parts slaked lime, two parts copperas, and one part finely ground indigo 
 into a vessel filled with water, and stirring occasionally for a day or two, 
 when the indigo is dissolved. Thus, the first action which takes place is 
 the decomposition of the metallic salt by the acid, which is in union with 
 the iron, combining with a portion of the lime, forming sulphate of lime 
 and pro-oxide of iron. The oxide of iron, according to old theory, takes 
 oxygen from the indigo, converting it into indigogen (white indigo), and 
 the peroxide of iron and the sulphate of lime thus formed are precipitated, 
 forming what is technically termed sludge. The remaining portion of lime 
 in solution dissolves the indigogen, and forms with it the solution required. 
 The following diagram represents this action and the results more clearly, 
 and gives the old view of the theory of the blue vat : — 
 
 Indigo, com- J Indigogen 7 Dyeing solution. 
 
 posed of ... ( Oxygen 
 
 ( Oxide of iron..- 
 
 2 Copperas... J of iron.. Peroxide of iron. 
 
 I Sulphuric acid' 
 
 [ Sulphuric acids 
 ( Lime 
 
 3 Lime < Lime ....- Sulphate of lime. 
 
 I Lime —^Sulphate of lime. 
 
 According to the view which is now taken of the constitution of indigo, 
 the action which takes place in the vat will be somewhat different from that 
 
254 
 
 INDIGO BLUE VAT. 
 
 given above. When the lime combines with the acid of the copperas, the 
 iron decomposes a portion of water combining with its oxygen, and the 
 hydrogen combines with the indigo, forming indigogen, which may be 
 represented as follows: — 
 
 2 Indigo.... | Indigo 
 
 Water ( 2 Hydrogen... 
 
 { Oxygen 
 
 ( Lime 
 
 3 Lime ) Lime 
 
 ( Lime 
 
 { Oxide of iron 
 Oxide of iron 
 Sulphuric acid 
 Sulphuric acid 
 
 2 Indigogen, forming 
 dyeing solution. 
 
 Peroxide of iron, 
 v -X Sulphate of lime. 
 —A\ Sulphate of lime. 
 
 This theory is equally, if not more beautiful than the former, and is 
 now all but generally accepted by chemists. When the goods are put into 
 the vat, the dissolved indigogen combines with them, and when brought 
 into contact with the air, according to the former theory, the indigogen 
 combines with oxygen, for which it has a strong disposition, and insoluble 
 blue indigo is formed, and remains combined with the cloth; according to 
 the latter theory, the blue indigo is left in combination with the cloth by 
 the extra hydrogen in the indigogen combining with the oxygen of the 
 atmosphere, and forming water. The supposition that hydrogen should 
 combine with the free oxygen of the air, and form water so rapidly under 
 such circumstances, is somewhat anomalous, but this is no reason for 
 rejecting it. If a mixture of copperas and lime be put into a bottle with 
 distilled water, the water is not decomposed ; the lime combines with the 
 acid, which, along with the iron, is precipitated, and if the air be com- 
 pletely excluded, the iron remains as a protoxide for days; indeed, the 
 change from a protoxide .to a peroxide is so slow that a long time elapses 
 before it is appreciable ; but if indigo be added, even after the mixture has 
 stood for some time, the action of the common vat proceeds. This gives a 
 beautiful illustration of relative affinities. Before the indigo is introduced, 
 the attraction of the iron for oxygen is about equal to that of the hydrogen, 
 which holds it in combination as water ; but when the indigo is introduced, 
 although its attraction for hydrogen must be very weak, as it requires the 
 nicest management to get that compound isolated, still it is sufficient to 
 disturb the equilibrium with which the oxygen was held by the iron and 
 hydrogen, giving the former the mastery. The presence of an alkaline 
 substance has no doubt an effect of inducing, if we ma} 7- be allowed the term, 
 the formation of indigogen; it is never formed in the vat without the 
 presence of some free alkaline substance to dissolve it the moment it is 
 formed. This circumstance indicates that the alkali has also an affinity 
 for indigogen, and may assist the reaction in the vat. 
 
INDIGO BLUE VAT. 
 
 2 55 
 
 We would recommend the reader to re-peruse the remarks upon the 
 salts of iron, in connection with these on the blue vat, in order that he 
 may be better able to appreciate them, and especially to understand what 
 ought to be the properties of good copperas from the part it is required 
 to play in the vat; also why it is that the quality of the copperas makes so 
 great a difference in the working of a blue vat. 
 
 There is one serious annoyance often experienced in working the vat, 
 technically called swimming — that is, the precipitate not properly settling 
 down, so that the goods come in contact with it, to the serious injury of 
 the colour. This may be occasioned by several circumstances. Should 
 the copperas have an excess of acid, either from its being crystallised out 
 of an acid solution, or from its having sulphate of alumina in it (as de- 
 scribed at page 132), it will form a sulphate of lime, which will not 
 precipitate so quickly as that formed by the decomposition of good copperas ; 
 but the prevailing cause of a floating vat is excess of copperas and lime. 
 Let the dyer take a solution of copperas or protosulphate of iron, and one of 
 persulphate, and add to each a sufficient quantity of lime to precipitate the 
 iron, he will find that the peroxide of iron will precipitate rapidly and com- 
 pletely, and that the protoxide will precipitate slowly and incompletely. 
 The same phenomenon takes place in the vat when lime and copperas are 
 added ; sulphate of lime and protoxide of iron are formed, and if there be not 
 enough of indigo to convert the protoxide of iron to the state of peroxide — 
 in which state it 'precipitates easily — the protoxide will remain floating 
 for a long time, the only cure for which is the addition of a little 
 indigo, or of a substance that will peroxidise the iron. When vats become 
 weak, great care should be taken not to add an excess of copperas. We 
 have seen a little soda added to a floating vat as a cure; and if the 
 evil consisted in the over quantity of copperas, this mode of cure 
 might be successful, but not otherwise. A floating vat is sometimes caused 
 by using improper lime. When slaked lime lies exposed for a short time 
 to the air, and more especially in such as is in a dye-work, it absorbs 
 carbonic acid, and becomes converted into chalk, and this put into the vat 
 is very deleterious in other respects, besides causing swimming. The lime 
 used for the vat should always be neivly slaked. This is a necessary pre- 
 caution, as the practice is too often otherwise than is here recommended. 
 
 When the paucity of indigo in the last stages of a vat causes swimming, 
 a small portion of a copper salt may be of service, as this oxide will give 
 up a part of its oxygen to the iron, becoming a sub oxide ; or it will 
 oxidise a portion of the indigo in solution, and this would react in turn 
 upon the iron. The property of this and some other metals for neutralising 
 the effects of iron in the vat has already been noticed ; but it may be more 
 apparent by thus referring to it here, and it may be still further enforced 
 in connection with that branch of calico-printing called resist-work , indi- 
 cated at page 248, and which may be thus further described : — A certain 
 preparation — the best we believe is the sulphate of copper or zinc — mixed 
 either with flour paste, with gum, or with pipe-clay and gum, and printed 
 
256 
 
 INDIGO BLUE VAT. 
 
 on the calico, of any pattern that may be desired ; when this is sufficiently 
 dry, the goods are dyed in the blue vat; those parts of the piece which 
 are printed with the copper or zinc will not be dyed blue, because the 
 deoxidised indigo becomes oxygenated the moment it touches the copper, 
 which yields its oxygen to the indigo, and occasions it to become insoluble, 
 and consequently incapable of forming a dye; or the hydrogen, in com- 
 bination with the indigo, unites with the oxygen of the copper, and forms 
 water — the results are alike in both. 
 
 Before concluding this article, we may inform the general reader that 
 in print-works and dye-houses where piece-goods are dyed blue, the vats 
 are necessarily large, being generally about 3 feet wide by 5 feet long 
 and 8 feet deep, made of iron, but sometimes of stone, and are sunk into 
 the ground about half their depth. The goods to be dyed are stretched 
 upon a frame, and the whole is lowered into the vat. Sometimes these 
 frames are furnished with rollers, when, instead of fixing the piece on 
 hooks, it is passed over these rollers while in the vat, by which means long 
 pieces are dyed perfectly regular in colour. 
 
 The vats for yarn or skein used to be small, being generally old wine 
 or oil pipes ; these were sunk about half their depth into the ground. 
 These kind of vats are now going out of -use, and large iron vats, as 
 described above, are taking their place. Wooden pins about 3 feet long are 
 put through the skein, and rest upon the edge of the vat; the skein is then 
 turned over, the one-half dipping in the liquor, the other half over the pins. 
 The time of this operation varies according to the strength of the vat and 
 depth of blue required; when the skein is taken out, wrung, and exposed 
 to the air, if the colour is not deep enough it is dipped again, and so 
 on, alternately dipping and exposing, till the requisite shade is obtained. 
 
 To prepare the vat, it is filled to within a few inches of the mouth 
 with cold water, the dyeing ingredients are then added ; the proportions 
 given in most chemical books are, 1 part (by weight) indigo, 2 parts 
 sulphate of iron, and 3 parts lime ; but the practical dyer does not consider 
 his vats in good condition when these proportions are used at the first set- 
 ting. The following are good proportions for preparing one of these small 
 vats — assuming all the ingredients good : — 8 pounds of indigo, 14 pounds of 
 copperas, and from 18 to 20 (not above 20) of slaked lime. If the copperas 
 be bad, a pound or even 2 pounds more of it may be required, along with 
 2 or 3 additional pounds of lime, to obtain the same results: These in- 
 gredients being put in, the whole is well stirred every two or three hours 
 during the day, and after settling for twelve hours, the vat is ready for use. 
 
 The chemical equivalents of lime may be calculated from the table of 
 elements, and also the rate of combination. Thus, slaked lime is the 
 hydrated oxide of calcium — 
 
 Lime, ... . . CaO == 56 
 
 Water, . . ... H 2 0 =- 18 
 
 74 
 
INDIGO BLUE. 
 
 257 
 
 And again we have — 
 
 Copperas, 
 
 Water of crystallisation, 
 
 FeS0 4 = 152 
 7 H 2 0 = 126 
 
 278 
 
 Thus, by equivalents, 74 lbs. of slaked lime should neutralise 278 lbs. 
 of crystals of copperas ; but as 77 gallons of water, at 60°, can dissolve 
 only 1 pound of lime, it is easy to see how a few pounds are required 
 above the equivalent for copperas to form the lime solution of the vat to 
 dissolve the indigogen. How it is that practice dictates such a quantity of 
 lime to be used is deserving of inquiry ; we merely hint that it may be that 
 the compound of indigogen and lime is more soluble than lime alone. 
 
 The indigo used for making up a vat is ground in water by means of 
 machinery, in proportion of about 3^- lbs. of indigo to the gallon of water ; 
 it is ground until the whole forms a fine paste, and not the slightest 
 grittiness is felt when rubbed between the fingers. 
 
 Woad and Pastel. — We have already alluded to these vegetables as 
 yielding a variety of indigo which has been long used for dyeing woollen 
 goods. It is still extensively used for that purpose, especially on the Con- 
 tinent; and as a description of the process, as it is there followed out, 
 may be interesting to many of our readers, we extract the following from 
 Dumas’s Lectures on Dyeing : — 
 
 “ Indigo Blue. — We give a solid dye of indigo blue to wool by 
 plunging it into an alkaline solution of indigo white, and then exposing it 
 to contact with the air. The solution of indigo white is prepared in a 
 vessel usually from 8 to 9 feet in depth, and 6 to 7 feet in diameter. This 
 size is very convenient for the requisite manipulations, and presents a 
 large volume of water, which, when once heated, is capable of preserving 
 a high temperature for a long time. This vessel should be made of wood 
 or copper. It always bears the name of vat. These vats are covered with 
 a wooden lid, divided into two or three equal segments. Over this lid are 
 spread some thick blankets. Without this precaution the bath would 
 come in contact with the atmospheric air ; a portion of the indigo would 
 absorb oxygen, and become precipitated. There would also be a great 
 waste of heat. 
 
 “ A most necessary operation, and one which has to be frequently 
 repeated, consists in stirring up the deposit of vegetable and colouring 
 matter which is formed in the vat, and intimately mixing it in the bath. 
 For this purpose we employ a utensil called a rake , which is formed of a 
 strong square piece of wood set on a long handle. The workman takes 
 hold of this with both hands, and, dipping the flat surface' into the deposit 
 at the bottom of the vessel, he quickly draws it up until it nearly reaches 
 the surface, when, giving it a gentle shake, he discharges the matter again 
 
 R 
 
258 
 
 INDIGO BLUE. 
 
 through the liquor of the bath. This manoeuvre is repeated until the 
 whole of the deposit seems to be removed from the bottom of the vessel. 
 Before the tissue is dipped into the dye-bath it should be soaked in a 
 copper full of tepid water ; it is then to be hung up and beaten with sticks. 
 In this state it is plunged into the vat ; it thus introduces less air into the 
 bath, while it is more uniformly penetrated by the indigo solution. The 
 cloth is now kept at a depth of from two to three feet below the surface 
 of the liquid, by means of an open bag or piece of network fixed in the 
 interior of an iron ring, which is suspended by cords, and fixed to the out- 
 side of the vat by means of two small iron hooks ; the bag is thus drawn 
 backwards and forwards without permitting it to come in contact with the 
 air. When this operation has been continued for a sufficient length of 
 time, the cloth is wrung and hung up to dry. 
 
 u Flock wool is also, for the purpose of dyeing, enclosed in a fine net, 
 which prevents the least particle from escaping, and which is fixed in the 
 bath in the same way as in the foregoing case. 
 
 “ The many inconveniences attending the use of wooden baths, which 
 necessitate the pouring of the liquor into a copper for the purpose of giving 
 it the necessary degree of heat, have led to the general employment of 
 copper vessels. These are fixed in brickwork, which extends half way up 
 their surface, whilst a stove is so constructed at this elevation that the 
 flame shall play around their upper part. By this means the bath is 
 heated and kept at a favourable temperature, without the liquor being 
 obliged to be removed. 
 
 “ The potash vats are usually formed of conical-shaped coppers, sur- 
 rounded by a suitable furnace. These may be constructed with less depth, 
 inasmuch as there is less precipitation induced in the liquor. By using 
 steam for heating the vats, we might dispense with the employment of 
 copper vessels, and so return to those of wood. 
 
 “ The vats employed for dyeing wool are known under the names of 
 the pastel vat, the woad vat, the potash vat, the tartar lee vat, and the 
 German vat. 
 
 “ The pastel is cultivated in France, Piedmont, England, and Saxony. 
 It is distinguished into several varieties, according to the localities in 
 which it is grown. We have already stated that the pastel contains a 
 blue-colouring matter, identical with indigo, and a fawn-coloured yellow 
 matter, which may easily be separated by treating the pastel-balls by hot 
 water, before the fermentative process is established. The woad is cul- 
 tivated in Normandy ; it contains less colouring matter, whether blue or 
 yellow, than the pastel ; its durability is also inferior to that of the last- 
 named substance. M. Chevreul has given an analysis of the pastel, which 
 will tend to throw some light upon its use. 
 
 “ When the leaves are subjected to the action of the press, we obtain, 
 on the one hand, a residue of a ligneous nature, and, on the other, a juice 
 which holds in suspension sundry matters which give it a cloudy appear- 
 ance. Thrown on a filter, it leaves a greenish matter or fecula, which is 
 
PASTEL VAT. 
 
 259 
 
 formed of chlorophyl, wax, indigo blue, and an azotised substance. The 
 clear liquid, after passing through the filter, contains an azotised substance, 
 coagulable by heat ; an azotised substance, non-coagulable by heat ; a red 
 matter, resulting from the union of the blue-colouring principle with an 
 acid ; a yellow principle ; gummy matter ; some liquid sugar ; a fixed 
 organic acid ; free acetic acid and acetate of ammonia ; the odorous prin- 
 ciple of the Cruciferse ; a volatile principle, having the odour of osmazome ; 
 citrate of lime ; sulphates of lime and potash ; phosphates of lime ; mag- 
 nesia, iron, and manganese ; nitre and chloride of potassium. 
 
 “ M. Chevreul has not discovered in these products any body possessed 
 of the power of seizing upon oxygen in an energetic manner, and which 
 would explain the action of the pastel in the indigo vat. Still we cannot 
 doubt that the principles furnished by this matter intervene, to a certain 
 extent, as combustibles, and that we must refer at least a part of their 
 effect to this mode of action. The indigo should itself be selected with 
 care. The Guatemala variety is preferred for the urinary or Indian vat, 
 and the Bengal indigo for the pastel vat. 
 
 “ Pastel Vat. — The first care of the dyer in preparing the vat should 
 be to furnish the bath with matters capable of combining with the oxygen, 
 whether directly or indirectly, and of giving hydrogen to the indigo. We 
 must, however, be careful to employ those substances only which are 
 incapable of imparting to the bath a colour which might pro ve injurious 
 to the indigo. These advantages are found in the pastel, the woad, and 
 madder. This latter substance furnishes a violet tint when brought into 
 contact with an alkali, and by the addition of indigo it yields a still deeper 
 shade. 
 
 “ In preparing the Indian vat we ordinarily employ 1 lb. of fine madder 
 to 2 lbs. of indigo. The madder is here especially useful, by reason of the 
 avidity of some of its principles for oxygen. 
 
 u The pastel vat, when prepared on a large scale, ordinarily contains 
 from 18 to 22 lbs. of indigo ; 11 lbs. of madder would suffice for this pro- 
 portion, but we must also bear in mind the large quantity of water which 
 we have to charge with oxidisable matters. I have invariably seen the best 
 results from employing 22 lbs. to a vat of this 'size. Bran is apt to excite 
 the lactic fermentation in the bath, and should, therefore, not be employed 
 in too large a quantity: 7 to 9 lbs. will be found -amply sufficient. 
 
 “ The weld is rich in oxidisable principles : it turns sour, and passes 
 into the putrid fermentation with facility. Some dyers use it very freely ; 
 but ordinarily we employ in this bath an equal quantity of it to that of the 
 bran. Sometimes weld is not added at all. 
 
 “ In most dye-houses the pastel is pounded before introducing it into 
 the vat. Some practical men, however, maintain that this operation is 
 injurious, and that it interferes with its durability. This is an opinion 
 which deserves attention. The effect of the pastel, when reduced to a 
 coarse powder, is more uniform ; but this state of division must render its 
 
260 
 
 PASTEL VAT. 
 
 alterations more rapid. When the bath has undergone the necessary- 
 ebullition, the pastel should be introduced into the vat, the liquor de- 
 canted, and, at the same time, 7 or 8 lbs. of lime added, so as to form an 
 alkaline ley which shall hold the indigo in solution. Having well stirred 
 the vat, it should be set aside for four hours, so that the little pellets shall 
 have time to become thoroughly soaked, both inside and out, and thus be 
 prepared for fermentation. Some thick coverings are to be spread over the 
 vat, so as to preserve it from contact with the atmosphere. After this 
 lapse of time, it is to be again stirred. The bath at this moment presents 
 no decided character ; it has the peculiar odour of the vegetables which it 
 holds in digestion ; its colour is of a yellowish-brown. 
 
 “ Ordinarily, at the end of twenty-four hours, sometimes even after 
 fifteen or sixteen, the fermentive process is well marked. The odour be- 
 comes ammoniacal, at the same time that it retains the peculiar smell 
 of the pastel. The bath, hitherto of a brown colour, now assumes a 
 decided yellowish-red tint. A blue froth, which results from the newly- 
 liberated indigo of the pastel, floats on the liquor as a thick scum, being 
 composed of small blue bubbles, which are closely agglomerated together. 
 A brilliant pellicle covers the bath, and beneath we may perceive some 
 blue or almost black veins, owing to the indigo of the pastel which rises 
 towards the surface. If the liquor be now agitated with a switch, the 
 small quantity of indigo which is evolved floats to the top of the bath. 
 On exposing a few drops of this mixture to the air, the golden yellow 
 colour quickly disappears, and is replaced by the blue tint of the indigo. 
 This phenomenon is due to the absorption of the oxygen of the air by the 
 indigogen from the pastel: in this state we might even dye wool with it 
 without any further addition of indigo ; but the colours which it furnishes 
 are devoid of brilliancy and vivacity of tone, at the same time that the 
 bath becomes quickly exhausted. 
 
 “ The signs above described announce, in a most indubitable manner, 
 that fermentation is established, and that the vat has now the power of 
 furnishing to the indigo the hydrogen which is required to render it 
 soluble, that contained in the pastel having been already taken up. This, 
 then, is the proper moment for adding the indigo, which should be pre- 
 viously ground in a mill. 
 
 “We stated above that the liquor of the vat should be previously 
 charged with a certain quantity of lime : we also find in it ammonia gene- 
 rated by the pastel; but a part of these alkalies becomes saturated by the 
 carbonic acid gas along with the proper acids of the madder and of the 
 weld, as well as by the lactic acid produced by the bran during fermenta- 
 tion. The ordinary guide of the dyer is the odour which, according to 
 circumstances, becomes more or less ammoniacal. The vat is said to be 
 either soft or harsh ; if soft, a little more lime should be added to it. The 
 fresh vat is always soft : it exhales a feeble ammoniacal odour, accom- 
 panied with the peculiar smell of the pastel ; we must therefore add lime 
 to it along with the indigo. We usually employ from 5 to 6 lbs., and, 
 
WOAD VAT. 
 
 261 
 
 after having stirred the vat, it is to be covered over. The indigo, being 
 incapable of solution except by its combination with hydrogen, gives no 
 sign of being dissolved until it has remained a certain time in the bath. 
 We may remark that the hard indigoes, as those of Java, require at least 
 eight or nine hours, whilst those of Bengal do not need more than six 
 hours, for their solution. We should examine the vat again three hours 
 after adding the indigo. We ordinarily remark that the odour is by this 
 time weakened : we must now add a further quantity of lime, sometimes 
 less, but generally about equal in amount to the first portion ; it is then to 
 be covered over again, and set aside for three hours. 
 
 “ After this lapse of time the bath will be found covered with an 
 abundant froth, and a very marked copper-coloured pellicle ; the veins 
 which float upon its surface are larger and more marked than they were 
 previously; the liquor becomes of a deep yellowish-red colour. On dip- 
 ping the rake into the bath, and allowing the liquid to run off at the edge, 
 its colour, if viewed against the light, is of a strongly- marked emerald- 
 green, which gradually disappears in proportion as the indigo absorbs 
 oxygen, and leaves in its place a mere drop, rendered opaque by the blue 
 colour of the indigo. The odour of the vat at this instant is strongly 
 ammoniacal ; we also find in it the peculiar scent of the pastel. When we 
 discover a marked character of this kind in the newly-formed vat, we may 
 without fear plunge in the stuff intended to be dyed ; but the tints given 
 during the first working of the vat are never so brilliant as those subse- 
 quently formed: this is owing to the yellow-colouring matters of the 
 pastel, which, aided by the heat, become fixed on the wool at the same 
 time as the indigo, and thus give to it a greenish tint. This accident is 
 common both with the pastel and the woad vats ; it is, however, less 
 marked in the latter. 
 
 “ When the stuff or cloth has been immersed for an hour in the vat it 
 should be withdrawn ; it would, in fact, be useless to leave it there for a 
 longer time, inasmuch as it could absorb no more of the colouring prin- 
 ciple. It is therefore to be taken from the bath and hung up to dry, when 
 the indigo, by attracting oxygen, will become insoluble and acquire a blue 
 colour. Then we may replunge the stuff in the vat, and the shade will 
 immediately assume a deeper tint, owing to renewed absorption of indigo 
 by the wool. By repeating these operations we succeed in giving very 
 deep shades. We must not, however, imagine that the cloth seizes only 
 on that portion of indigo contained in the liquor required to soak it. Far 
 from such being the case, experience shews that, during its stay in the 
 bath, it appropriates to itself, within certain limits, a gradually increasing 
 quantity of indigo. We have here, then, an action of affinity, or perhaps 
 a consequence of porosity on the part of the wool itself. 
 
 “ Woad Yat. — These vats are extensively employed at Louviers, and 
 in the manufactories of the north of France. The bath is prepared in the 
 same manner as in the foregoing case : the finely-cut root is introduced 
 
262 
 
 MODIFIED PASTEL VAT. 
 
 into the copper along with 2 lbs. of pounded indigo, 9 lbs. of madder, 
 and 15i lbs. of slaked lime. The liquor is, after the necessary ebullition, 
 poured upon the woad. This substance contains but a very small quantity 
 of colouring principle; we must, therefore, add some indigo when pre- 
 paring the vat, so- as- to indicate the precise instant when the mixture 
 arrives at the point of fermentation so necessary for imparting hydrogen 
 to the colouring principle, and for rendering it soluble. We must also use 
 a larger quantity of lime, since the woad contains no ammonia resulting 
 from previous decomposition, such as we find to be the case with the pastel 
 of the south. When the vat is in a suitable state of fermentation, a rusty 
 colour becomes manifest, in addition* to the signs already described in 
 speaking of the pastel vat ; besides the ammoniacal odour, the bath 
 always retains the peculiar smell of the woad. The pounded indigo is 
 now added, and we proceed, in the manner already detailed, to reduce it 
 to a state of solution fit for dyeing. 
 
 “ The vats prepared by means of pastel have greater durability than 
 those made with the woad; but it is thought that the colours given by the 
 latter are more brilliant than those obtained from the former dye. 
 
 “Modified Pastel Yat. — This vat is about 7 feet in depth, and 
 feet in diameter. It is made of copper, and heated by steam. The lid is 
 composed of three segments, each of which is formed of two planks, about 
 an inch thick, and strongly secured together by bolts. 
 
 “ The beating is performed in the usual way, with sticks, before the 
 first dipping, after having moistened the cloth in tepid water. This opera- 
 tion is not subsequently repeated. 
 
 “ This vat is prepared with 13 lbs. of indigo, 17^ lbs. of madder, 4£ 
 lbs. of bran, 9 lbs. of lime, and 4£ lbs. of potash. Having filled the vat, 
 we heat it to about 200° Fah., and as soon as the water is tepid introduce 
 441 lbs. of pastel. The liquor becomes of a yellowish-brown colour ; small 
 bubbles appear upon its surface, ordinarily at the end of four hours if the 
 vat be heated by steam, but not until after eight or twelve hours where 
 heat is applied by the common fire : in the latter case the mixture should 
 be stirred every three hours. When the liquor displays the signs of fer- 
 mentation, we add the above-mentioned ingredients, and cover the vat 
 over; it is then to be set aside, stirring it every three hours, or oftener if 
 the fermentative action be very rapid.. Each time that it is stirred we are 
 to add from 2 to 4 lbs. of lime ; if fermentation proceed quickly we even 
 use more, but in the contrary case less. After about eighteen hours we 
 plunge into the vat three pieces of common cloth, measuring 20 to 25 ells 
 in length each ; when they have received six or seven turns they are to be 
 taken out again. The object of this is to remove the excess of lime from 
 the bath. The vat is then set aside for three hours, when it is to be stirred, 
 and 13 lbs. of indigo, wfith 2 lbs. of madder, added to it. We now again 
 apply heat to the mixture. 
 
 “ If the vat contain a superabundance of lime, it will be unnecessary 
 
INDIAN VAT. 
 
 263 
 
 to add more ; otherwise we throw in a further quantity. During the night 
 it should be covered with a cloth, and a workman left to watch it. It is 
 usually stirred once before the morning; but if it be deficient in lime, it 
 will require this manipulation to be more frequently repeated, and also 
 fresh lime added to it. On the following day the stirring should be con- 
 tinued every three hours, and so on for the next thirty hours, taking care to 
 heat the vat from time to time. On the morning of the fourth day the 
 dyeing may be commenced. 
 
 “ The temperature should be maintained at a pretty uniform point ; if 
 it be too hot the blue takes a red reflection, by reason of the madder con- 
 tained in the liquid. A vat thus prepared will last three months ; we may 
 even work it for double that period, but after the third month it appears 
 to lose some of its indigo. 
 
 “We maintain the power of the vat by introducing every night lbs. 
 of madder. Some indigo is also added twice or three times a week. These 
 additions are made in the evening. After the former, the vat is left at rest 
 for forty-two hours ; with the latter, only for twenty-four, at the same 
 time observing the precautions already indicated. At the end of three 
 months, or sooner, when we wish to stop the working of the vat, we 
 exhaust the indigo ; for this purpose we continue to charge it every night, 
 for the space of a month, with madder, and dip into it white cloths, or 
 more particularly woollen tissues, which become more or less loaded with 
 the indigo. We must continue this plan until these matters take up no 
 further colour. The dippings are to be performed twice a day at first, but 
 once only towards the termination. Many dyers make use of this bath for 
 preparing a new vat ; but it is better to throw this away and make it up 
 afresh with common water. 
 
 “ Indian Yat. — These vats are of more simple and of more ready 
 construction than the pastel or woad vats. We are- to boil in water a 
 quantity of madder and of bran, proportioned to- the weight of indigo 
 which we wish to employ. After two hours’ ebullition, we turn into this 
 bath some tartar-lees, which are also to be boiled for an hour and a half or 
 two hours, so as to charge the bath with whatever soluble matter they may 
 contain ; after this ebullition, the bath should be allowed to cool, and the 
 indigo, which has been previously ground, is then to be introduced'. Sup- 
 posing that we wish to employ 21 lbs. of indigo, the following would be 
 the proportions used in preparing this vat-: — 41 lbs. of tartar-lees, 13 lbs. 
 of madder, and 5 lbs. of bran. These vats are usually mounted in coppers 
 of a conical shape ; a small fire should be kept up around them, so as to 
 maintain a moderate and uniform heat. The indigo will usually be found 
 dissolved at the end of twenty-four hours, often even after twelve or 
 fifteen hours. The liquor has a reddish colour in the new vats, and a 
 green tint in those ‘which are in a working state. The frothy surface, as 
 well as the brilliant-coloured pellicle, become manifested in this as in all 
 other preparations of a like kind. 
 
264 
 
 GERMAN YAT. 
 
 “ This species of vat has to be renewed much more frequently than 
 the woad and pastel vats, from the indigo being more difficult to dissolve 
 after a certain lapse of time. A moderate heat should be maintained in 
 these vats. 
 
 “ Potash Yat. — This species of vat is extensively employed at Elbeuf 
 for the dyeing of wool in the flock. It presents in all respects a perfect 
 analogy with the Indian vat ; in fact, the action of the tartar-lee in the 
 latter preparation depends entirely on the carbonate of potash which it 
 contains. The ingredients used in the preparation of the potash vat are — 
 bran, madder, and the subcarbonate of potash of commerce. 
 
 “We obtain the deep shades in this species of vat with greater celerity 
 than in all others — a fact which undoubtedly depends on the greater power 
 which potash has of dissolving indigo than is possessed by lime. Expe- 
 rience proves that the potash vat has the advantage in point of celerity of 
 nearly a third ; but this is balanced by the inconvenience resulting from 
 the darker shade, which we must attribute to the large quantity of colour- 
 ing matter of the madder dissolved by the alkaline lee, and which becomes 
 fixed on the stuff with the indigo. 
 
 “ To render this vat in its most favourable state, the indigo should be 
 made to undergo a commencement of hydrogenation before turning it into 
 the mixture ; for this purpose we prepare, in a small copper, a bath analo- 
 gous to that in the vat, to which the pounded indigo is added. This bath 
 is maintained, for twenty-four hours, at a moderate heat, taking care to 
 stir it from time to time. The indigo assumes a yellowish colour, becomes 
 dissolved, and in this state is turned into the vat ; we thus avoid many 
 delays and losses in its preparation, and, indeed, it would be desirable if a 
 similar plan were adopted with all these compounds. 
 
 “ German Yat. — This vat is of nearly similar dimensions to that used 
 for the woad, being three times the size of the potash vat. Its diameter is 
 about 6^ feet, and its depth 8^- feet. Having filled the copper with water, 
 we are to heat it to 200° Fah. ; we then add 20 pailsful bran, 22 lbs. of 
 carbonate of soda, 11 lbs. of indigo, and 5^ lbs. of lime, thoroughly 
 slaked in powder. The mixture is to be well stirred, and then set aside 
 for two hours ; the workman should continually watch the progress of the 
 fermentation, moderating it more or less by means of lime or carbonate of 
 soda, so as to render the vat in a working state at the end of twelve, 
 fifteen, or at the most eighteen hours. The odour is the only criterion 
 by which the workman is enabled to judge of the good state of the vat; 
 he must, therefore, possess considerable tact and experience. 
 
 “ In the process of dipping we introduce 84 lbs., 106 lbs., or even 
 130 lbs. of wool, in a net bag, similar to that used in the woad vat, taking 
 care that the bag is not allowed to rest against the sides of the copper. 
 When the wool has sufficiently imbibed the colour, we remove the bag 
 containing it, and allow it to drain for a short time over the vessel. We 
 
MANAGEMENT OF THE VATS. 
 
 265 
 
 operate in this way on two or three quantities in succession ; we then 
 remove the vat, and set it aside for two hours ; we must be careful, from 
 time to time, to replace the indigo absorbed by the wool, as also to add 
 fresh quantities of bran, lime, and crystallised carbonate of soda, so as 
 constantly to maintain the fermentation at a suitable point. 
 
 “ The German vat differs, then, from the potash vat by the fact that 
 the potash is replaced by crystallised carbonate of soda and caustic lime, 
 which latter substance also gives to the carbonate of soda a caustic 
 character. It presents a remarkable saving as compared to the potash vat ; 
 hence the frequency of its employment ; but it requires great care, and is 
 more difficult to manage. It also offers considerable economy of labour ; 
 one man is amply sufficient for each vat. 
 
 “ Tlie army cloth is usually dyed by means of the pastel vat, which 
 gives the most advantageous results. We here make use of vats about 
 8^ feet in depth and 5 feet in diameter, into which we introduce from 
 361 lbs. to 405 lbs. of pastel or of woad, after previous maceration. The vat 
 is to be filled with boiling water, and we then add to the bath 22 lbs. of 
 madder, 17^ lbs. of weld, and 13 lbs. of bran. The mixture is to be 
 maintained in a state of ebullition for about half an hour; we next add a 
 few pailsful of cold water, taking care, however, not to lower the temper- 
 ature beyond 130° Fah. ; during the whole of this time a workman, 
 provided with a rake, keeps incessantly stirring the materials of the bath. 
 The vat is then accurately closed by means of a wooden lid, and sur- 
 rounded by blankets, so as to keep up the heat. It is now put aside for 
 six hours; after this time it is again stirred, by means of a rake, for the 
 space of half an hour; and this operation should be repeated every three 
 hours until the surface of the bath becomes marked with blue veins ; we 
 then add from six to eight pounds of slaked lime. 
 
 “ The colour of the vat now borders on a blackish-blue. We 
 immediately add the indigo in a quantity proportioned to the shade 
 which we wish to obtain. The pastel in the foregoing mixture may last 
 for several months ; but we must renew the indigo in proportion as it 
 becomes exhausted, at the same time adding both bran and madder. In 
 general we employ — 
 
 “ 11 to 13 lbs. of good indigo for 100 lbs. of fine wool. 
 
 “ 9 to 11 lbs. of good indigo for 100 lbs. of common wool. 
 
 “9 to 11 lbs. of good indigo for 131 yards of cloth dyed in the piece. 
 
 “ Management of the Vats. — A good condition of the vat is recog- 
 nised by the following characters : — The tint of the bath is of a fine golden- 
 yellow, and its surface is covered with a bluish froth and a copper-coloured 
 pellicle. On dipping the rake into the bath, there escape bubbles of air, 
 which should burst very slowly ; when they vanish quickly, it becomes an 
 indication that we must add more lime. The paste which is found at the 
 bottom of the vat green at the moment of its being drawn up, should 
 become brown in the air; if, however, it remain green, this is a further 
 
266 
 
 MANAGEMENT OF THE VATS. 
 
 sign that more lime is required. Lastly, the vat should exhale the odour 
 of indigo. We usually complete the assurance of the vat being in a good 
 state by plunging into it, after two hours’ respite, a skein of wool, which, 
 on being withdrawn after the lapse of half an hour, should present a green 
 colour, but change directly to blue. We then once more mix the materials 
 of the vat, and, two hours after, it may be considered ready for dyeing. 
 
 “ These vats, like those already described, are provided with a large 
 wooden ring, the interior of which is armed with a kind of network, for the 
 purpose of preventing the objects which are intended to be dyed coming in 
 contact with the materials at the bottom of the vat; we, moreover, take 
 the precaution of enclosing the wool or cloth in bags. These tissues, when 
 plunged into the bath, should remain there for a longer or shorter time, 
 according to the shade which we wish to obtain ; one dipping, however, will 
 never suffice for this object; usually we leave in the stuff for half an hour 
 only; it is then to be taken from the bath, wrung, and exposed to the 
 air. This operation is repeated until we have succeeded in procuring the 
 desired shade; we ordinarily suffer three hours to elapse between each 
 dipping. The heat of the vat should never be allowed to fall below 130° 
 Fah. After each operation the bath must be well stirred, and fresh lime 
 added ; generally speaking, a pound a-day will suffice ; we re-establish the 
 indigo about every second day. When once this vat is well mounted, 
 and we are careful to examine its working, we may dye from two to four 
 batches a-day with it. 
 
 “ When the Stuffs have acquired the desired shade, they are first to 
 be washed in common water, and then in a very weak solution of hydro- 
 chloric acid (about one part in a thousand); after this they are again 
 rinsed in pure water. 
 
 “The Indian vat is much more easily managed than the foregoing; 
 it presents less danger of failure, from the fact that it is quickly exhausted, 
 and also from the fermentative process, which is so difficult to govern in 
 the pastel vat, here not having time to change in character. It is prepared 
 by first introducing an equal quantity of madder and of bran, and a triple 
 quantity of potash; this is to be gradually heated until it reaches a 
 temperature of 167° Fah., and we then add to it the indigo, thoroughly 
 agitating the matters for half an hour. The vat is maintained at a tem- 
 perature of 86° to 100° Fah., by keeping it closely covered, and at the 
 same time the mixture is to be stirred occasionally at intervals of twelve 
 hours. It should by this time present a beautiful green shade, the liquor 
 being surmounted by a copper-coloured pellicle and a purplish froth. 
 We may now commence the dyeing, following the same course as 
 with the pastel vat; but the stirrings being here repeated much more 
 frequently than with the other mixture, we can dye a larger quantity of 
 wool within a given time. When the vat ceases to give a brilliant blue, 
 we must altogether renew it; if it be merely weakened, we add to it a 
 small quantity of freshly-prepared liquor containing a few pounds of 
 potash, and a little less bran and madder. In giving the dark and the 
 
MANAGEMENT OF THE VATS. 
 
 267 
 
 clear sky-blues, we must be careful to employ a quantity of indigo pro- 
 portioned to the colour which we wish to obtain, or, better still, we may 
 use the previously exhausted vat for the dark blue. 
 
 “ When exposed to the influence of the putrid fermentation, indigo is 
 decomposed and loses its colour. If rendered soluble, it obeys the impulse 
 communicated to the azotised matters with which it is brought into contact, 
 although, if macerated in pure water at the ordinary temperature, it is itself 
 decomposed with great difficulty. 
 
 “ The pastel and the woad are very prone to the putrid fermentation, 
 by reason of the large quantity of azotised matters which they contain, as 
 do all the Cruciferse ; they require, therefore, considerable care in their 
 employment. 
 
 “ When a vat is mounted, if the fermentation be allowed to continue 
 unchecked, after the appearance of the blue froth and the other signs 
 already indicated, the liquor will acquire a yellow colour similar to that 
 of beer; the froth will become white; it will give out a stale smell and lose 
 its ammoniacal odour ; after a few days it will turn whitish, and exhale a 
 smell at first similar to that of putrefied animal substances ; then it will 
 acquire the odour of rotten eggs, and set free sulphuretted hydrogen. 
 The lime in the pastel and the woad vats, and the tartar-lee and potash 
 in the other mixtures, are used for the purpose of preventing these 
 accidents. 
 
 “ Besides the oxygenated compound, which is formed by the com- 
 bination of oxygen with the extractive matters of the plants held in 
 digestion, there is a production of carbonic acid which saturates the 
 alkaline lee, and forms a carbonate of lime in the pastel vat. We find 
 this attached to the sides of the vat in such quantity, that the inside of 
 these vessels becomes encrusted with it to a considerable depth. It is this 
 product which dyers call the tartar of the vat; it effervesces with acids, 
 and gives on analyses carbonic acid, lime, and a few particles of indigo. 
 In the potash vat the solubility of the carbonate of potash prevents its 
 deposition; but it is very probable that we have even here a formation of 
 some carbonated products, perhaps in part formed at the expense of the 
 carbonic acid of the air. 
 
 “ The soluble extractive principle being the only matter which remains 
 in solution in the bath with the indigo, the lime, &c., we have formed 
 deposits which, varying both in their volume, and in the greater or less 
 facility with which they are precipitated during the various periods of 
 fermentation, lead to a more or less considerable waste of time. If we 
 plunge a piece of woollen tissue into a vat which has been recently stirred, 
 it will acquire a dark colour, and will be found covered with brown stains 
 which are with difficulty removed. When the woad or pastel vat has been 
 stirred, it need be left two or three hours only before plunging in the stuff, 
 at least during the early months of its working, inasmuch as the pastel, 
 being but slightly divided and attenuated, is readily precipitated; but 
 when by reason of its extreme division, in consequence of repeated oper- 
 
268 
 
 MANAGEMENT OF THE VATS. 
 
 ations, it is thrown down with less facility, the dipping should not be 
 performed oftener than three times in the day. 
 
 “ The Indian vat requires less time than the others ; we may even dye 
 with it an hour after stirring the mixture. The potash, being soluble, 
 forms no precipitate; while the ligneous fibre of the madder and the 
 pellicles of the bran become deposited with great facility. We can also dip 
 with these vats much oftener than with those made by pastel or woad.” 
 
 Most of the French and German dyeing establishments are under the 
 direction of experienced chemists, and their methods of dyeing are syste- 
 matised, and are therefore easily described in detail. In this country the 
 practical manager may know nothing of chemistry, but follows his 
 experience, which is often a true guide; but as each manager’s experience, 
 from several causes, may lead to slightly different views on certain points, 
 there will be considerable modifications in many of the operations in 
 managing a vat or series of vats for different purposes, although the 
 principles may be the same. The details now given, although they may 
 differ in some points from what is practised in this country, embrace all 
 that is required in the management of the several vats ; experience and 
 observation will guide to modifications where required. It is when any- 
 thing goes wrong with the woad vat that often the dyer is put to his wits’ 
 end, if he does not understand the chemical principles of the action. We 
 have seen several weeks spent over a woad vat, and every conceivable filth 
 added to produce fermentation. 
 
 A very ingenious method for setting a vat for dyeing cotton was intro- 
 duced on the Continent a few years ago by using metallic zinc, ground to an 
 impalpable powder, instead of copperas. The zinc decomposes the water, 
 the hydrogen combining with the indigo forms indigogen, which is dis- 
 solved by the lime ; by this method there is no sludge formed. The 
 copperas and lime vat when stirred requires several hours, generally a 
 day to settle, and consequently can only be used once a day; but by the 
 zinc process the vat may be used several times a day, as after stirring 
 the vat settles in a short time. Notwithstanding these advantages, this 
 method has not met with general acceptance in this country. There 
 being several apparently small matters to be attended to making it trouble- 
 some in practice, and when compared with the old and usual method there 
 is less value got out of the indigo, in some cases to an extent of ten per cent. 
 Were the vats taxed, as we understand they are in Germany, it would be an 
 object to be able to use the same vat several times over during one day. 
 The following materials and proportions will be enough to set a vat of 
 ordinary size by this method : — 
 
 30 lbs. iron filings. 
 
 75 lbs. zinc preparation. 
 
 56 lbs. slaked lime. 
 
 100 lbs. indigo, finely ground. 
 
 Stir occasionally, and in six hours the vat may be worked. 
 
LOGWOOD. 
 
 289 
 
 Logwood. 
 
 Logwood is the Bois de Campeche and Bois bleu of the French, and the 
 Blauholz of the German dyers. This wood is brought to us from Jamaica 
 and from the eastern shores of the Bay of Campeachy, and on this account 
 is distinguished in commerce by the names of Campeachy and Jamaica log- 
 wood. The former is considered much superior to the latter, and brings 
 always a higher price in the market. Among botanists the logwood tree is 
 known by the name of Hxmatoxylon Campechiacum. In a favourable soil it 
 grows to a very great size ; its bark is thin and smooth, but € furnished with 
 thorns ; its leaves resemble the laurel ; the wood is hard, compact, and 
 capable of taking a fine polish ; its specific gravity is much higher than 
 water, in which it consequently sinks. 
 
 We are not aware who first introduced logwood as a dyeing agent ; 
 but its nature, and the art of using it as such, seem to have been but little 
 understood in the reign of Queen Elizabeth, for we find her government 
 issuing an enactment entirely forbidding its use. The document is curious, 
 and affords a good proof of the absurdity of a government interfering with 
 the industry of its subjects. The act is entitled, “An Act for the abolishing 
 of certeine deceitful stuffeused in the dyeing of clothes;” and it goes on 
 to state that, “ Whereas there hath been brought from beyond the seas a 
 certeine kind of stuffe called logwood, alias blockwood, wherewith divers 
 dyers,” &c., and “Whereas the clothes therewith dyed are not only solde 
 and uttered to the great deceyte of the Queene’s loving subjects, but 
 beyond the seas, to the great discredit and sclaunder of the dyers of this 
 realme. For reformation whereof, be it enacted by the Queene our 
 Soveraygne Ladie, that all such logwood, in whoes handes soever founde, 
 shall be openly burned by authoritie of the maior.”* This act was put 
 forth in the 23rd year of the queen’s reign, and was renewed again in the 
 39th, with the addition that the person so offending was liable to imprison- 
 ment and the pillory. Upwards of eighty years elapsed before the real 
 virtues of this dyeing agent were acknowledged; and there is no dyewood 
 we know now so universally used, and so universally useful. 
 
 Like many other valuable substances, logwood was long used before 
 anything was known of the real nature of the colouring principle. Chevreul 
 made a chemical examination of the wood, and found it to contain a distinct 
 colouring substance, which he called haematine, a name which was after- 
 wards changed to hsematoxylin, to avoid any confusion with a substance 
 having a similar name to the former contained in blood. Logwood contains, 
 besides this coluring matter, resin and oil, acetic acid, and a double salt of 
 potash and lime, with a vegetable acid. It sometimes contains also sul- 
 phate of lime, a little alumina, peroxide of iron, and oxide of manganese. 
 These ingredients, however, vary ; some woods having more than others, 
 and others wanting some altogether. These varieties of constitution 
 probably arise from the varying qualities of the soil on which the wood is 
 grown. 
 
 * Parke's Chemical Essays , 8vo, \ol. i, page 632. 
 
270 
 
 LOGWOOD. 
 
 We have frequently tried pieces of logwood as imported, and the 
 average ash left after burning was 1*5 per cent., half of which was lime 
 with a trace of iron, and the remainder consisted of magnesia, alumina, and 
 silica. 
 
 Chevreul’s process for procuring the colouring matter is by subjecting 
 logwood, after grinding, to digestion for a few hours in water at 120° or 
 130° Fah., afterwards filtering the liquor and evaporating to dryness; what 
 remains is put into strong alcohol for a day ; this is again filtered, and the 
 clear liquor evaporated till it becomes thick ; to this is added a little water 
 and evaporated anew; it is then left to itself, and the colouring matter 
 crystallises. 
 
 An improvement on this method has been recommended by Erdmann. 
 The extract of logwood being evaporated to dryness is pulverised, and 
 mixed with a considerable quantity of pure silicious sand, to prevent the 
 agglutination of the extract, and the whole allowed to stand several days 
 mixed with five or six times its volume of ether ; the mixture being often 
 shaken, the clear solution is poured off and distilled, until there is only 
 a small syrupy residue. By this means most of the ether is saved ; and 
 this residue being mixed with a certain quantity of water, is allowed to 
 stand for some days, when the hsematoxylin crystallises out, and may be 
 dried between folds of blotting paper. 
 
 We are afraid both of these processes will be too tedious for adoption 
 in a dye-house. We have seen some very good specimens of the hsema- 
 toxylin obtained by evaporating a strong decoction of logwood nearly to 
 dryness, and allowing it to stand for several days ; a solid matter settles to 
 the bottom, having a syrupy fluid above it ; large crystals of hsematoxylin 
 appear to grow from the crust, giving it, when removed, a most beautiful 
 velvety appearance. The crystals vary in length from one-fourth to five- 
 eighths of an inch. They dissolve readily in hot water, but very slowly in 
 cold; they are soluble in alcohol. When dissolved in distilled water, 
 the solution has a beautiful rich wine colour ; but when the least trace of 
 lime or iron is present in the water (and very few waters are free of these), 
 its colour is materially altered. The action of re -agents upon the solution 
 is very powerful. Potash when first put in colours the solution violet ; 
 but this speedily passes into a purple, becoming brownish-yellow, and in 
 a little time the mixture becomes almost colourless. The reason of this 
 final change is, that a quantity of oxygen is absorbed ; the hsematoxylin is 
 thereby destroyed, and the caustic alkali converted into a carbonate from 
 the decomposition of the colouring matter. Caustic soda has a similar 
 effect ; carbonate of soda is much more mild in its action than carbonate 
 of potash. 
 
 An extract of logwood is sold in France in a crystalline form, and is 
 obtained from a decoction of the wood. The crystals are dark red, nearly 
 black ; they are hsematoxylin with several impurities, but yield a very con- 
 siderable quantity of colour. 
 
 The action of ammonia on hsematoxylin is similar to that of potash and 
 
LOGWOOD. 
 
 271 
 
 soda, but much more powerful in regard to the changing colour, and less 
 destructive upon the substance. Some beautiful and also amusing experi- 
 ments may be performed with ammonia and the colouring matter of log- 
 wood. If a jar full of distilled water be taken, and a few drops of a 
 solution of hsematoxylin be added, not so much as to give a perceptible 
 colouring to the water ; on adding a few drops of ammonia, the water 
 instantly takes a reddish tint, and changes so rapidly that in two minutes 
 the colour is so dark a violet shade that the light is hardly transmitted; 
 in a little it becomes redder and gradually the colour passes away. 
 This experiment may be repeated by placing the jar simply in the fumes 
 of ammonia; the water begins to colour at the top, and as the absorp- 
 tion goes on the colour passes gradually down, so that when it is dark 
 at the top it is slightly tinged at the bottom, and so on till the whole is 
 converted into a dark violet, seemingly by magic. 
 
 Erdmann has been able to collect this compound of hsematoxylin and 
 ammonia, and finds that the colouring matter absorbs three equivalents of 
 oxygen under the influence of the ammonia, and is converted into a sub- 
 stance which he names hsematein. This hsematein combines with ammonia, 
 and forms a violet-black powder, which is soluble in water, giving it an 
 intense purple colour, which spontaneously fades and passes away by 
 keeping. 
 
 The action of the alkalies upon logwood is similar to those described 
 upon its colouring matter, and suggests the reason why those who add a 
 little alkali to their logwood liquor while dyeing black, on purpose to give 
 the colour of the logwood a richness and prevent the action of the iron 
 upon it, invariably have a bad greyish-black. Stale urine, indeed, which is 
 most generally used for this purpose, if not used cautiously, produces the 
 same bad colour from the ammonia which it contains. For this reason, also, 
 we advise washing from the lime, when it is used to pass the cloth through 
 after being impregnated with iron, otherwise the lime on the cloth will 
 cause the colouring matter to undergo similar changes, and give the 
 blacks thus dyed a greyish appearance. Indeed, so delicate is the action 
 of all earthy and alkaline salts upon logwood, that it has been proposed 
 as a test for the presence of lime in water. 
 
 In the chemical investigation of logwood, the colouring matter has 
 been obtained in two conditions, differing in chemical composition only in 
 one having more water than the other ; but these researches have led to 
 some curious and interesting speculations upon the relation which different 
 colouring matters of vegetables have to each other. They have not yet 
 been sufficiently investigated. The following is the composition of — 
 
 C. H. O. N. Water. 
 
 Protohydrate hsematoxylin, . . . 16 11 6 0 1 
 
 Perhydrate hsematoxylin, . . . . 16 14 6 0 3 
 
 When hsematoxylin oxidises in presence of an alkali, as when 
 a saturated solution in ammonia is agitated in contact with air, the liquid 
 becomes cherry-red, and deposits granular crystals of hsemateate of 
 
272 
 
 LOGWOOD. 
 
 ammonia ; if the ammonia be neutralised with acetic acid, there pre- 
 cipitates a brown-red substance like peroxide of iron, which is termed 
 hamatein ; its composition is expressed by Ci 6 H 12 0 6 , differing from 
 hsematoxylin by having two equivalents less hydrogen. Potash dissolves 
 this, giving a blue colour, becoming brown by exposure to the air. The 
 use of caustic alkalies with logwood colours is always followed by a 
 destructive result. 
 
 The action of metallic salts upon the colouring matter of logwood is 
 somewhat similar to the action of these salts on logwood itself, varying 
 considerably with the kind of acid, with the metal, and the particular state 
 of oxidation. 
 
 Protosalts of iron give... Blue -black precipitates, permanent. 
 
 Persalts of iron .....Jet-black precipitates, which become brown. 
 
 Protosalts of tin... ...Rich wine-colour precipitates, permanent. 
 
 Persalts of tin... .Deep wine-colour precipitates, which become 
 
 brown. 
 
 Acetate of lead ..Brownish-black precipitate, which passes to 
 
 grey. 
 
 Acetate of copper Greenish -black, passing to brown. 
 
 Salts of alumina Wine-colour precipitates, permanent. 
 
 These are the principal metallic salts used with logwood, and their 
 effects. The acid in which the oxides are dissolved affects materially the 
 results obtained; the iron should be used in the state of sulphate or 
 acetate, the tin as chloride, lead and copper as acetates. The protosalts 
 give with logwood the most brilliant and also the most permanent 
 colours: this should be constantly attended to. The iron protosalts, if 
 exposed to the air, pass very readily into the state of persalts, especially if 
 the salts be neutral — that is, havejio more acid than is combined with the 
 metal. A little free acid prevents this change, but generally produces bad 
 effects upon logwood. However, where the use of a protosalt of iron is 
 necessary, any persalt in the mordant may be reduced to the proto-state by 
 the immersion of a piece of clean iron a few hours previous to using 
 the solution. When an iron salt becomes peroxidised by exposure to the 
 air, every third atom is precipitated as an insoluble oxide — the acid leaving 
 this atom, and combining with two atoms iron and three oxygen to form 
 a persalt (page 131). When a piece of iron is put into a persalt solution 
 the following reaction takes place : — 
 
 Persalt of iron 
 composed of... 
 
 
 Iron .... 
 
 Iron 
 
 Oxygen 
 Oxygen 
 Oxygen 
 Acid.... 
 Acid.... 
 Acid. . . . 
 
 Protosalt. 
 
 Protosalt. 
 
 Piece of clean iron 
 
 Trotosalt. 
 
LOGWOOD. 
 
 273 
 
 This operation ought to be performed just previous to using the solution, 
 which should be as little exposed as possible ; for when the salt is all con- 
 verted into the proto -state, the atmosphere again speedily destroys it. 
 
 Decoctions of logwood are prepared in the dye-house either by boiling 
 or by scalding; if the logwood is chipped or cut it requires to be boiled for 
 two or three hours. This generally gives the purest and finest colours. 
 When the wood is ground, the decoctions are generally made by pouring 
 boiling water upon it. Some dyers put the quantity of wood required into 
 a tub ; fill this with boiling water, stir, and allow the grounds to settle, 
 and decant the solution ; but the best method is to use a basket lined 
 with cloth — the logwood is put into the basket, and boiling water is 
 poured upon it ; the clean decoction filters through. No more logwood 
 should be taken than what is to be used at the time, as it loses its dyeing 
 properties by standing; the colour passes from a rich wine hue to a 
 yellow-brown, and assumes a syrupy appearance; and colours dyed by 
 it after this change takes place are always wanting in brilliancy : besides, 
 it takes a greater quantity of stuff to produce the same depth of shade. 
 This may be caused by a partial decomposition of the colouring matter, 
 or by the other ingredients of the wood reacting upon the colouring 
 matter. 
 
 Parkes, in his Chemical Essays , has the following observations bearing 
 upon this subject Considerable advantage is derived by the woollen 
 dyers from the use of water in the preparation of rasped logwood. As the 
 wood is cut into chips, they sprinkle it abundantly with water, and in that 
 moistened state it is thrown into large heaps, and sometimes into bins of 
 great size, where it is suffered to lie as long as is convenient. By this 
 treatment the chips become heated, or they ferment, as the dyers call it, 
 and thus undergo a very remarkable change ; for, after having lain a few 
 months in this state, they give out the colouring matter in the dyeing 
 copper much more easily; and any given quantity of such chips will 
 produce a more intense dye than could have been obtained from an equal 
 quantity of chips which had not been thus heated. It is difficult to 
 account for this, unless we suppose that the water becomes in part decom- 
 posed, and that its oxygen, uniting with the vegetable colouring matter, 
 renders it more intense.” We have found that, by damping the wood 
 with boiling water a little before pouring the necessary quantity of boiling 
 water upon it, the wood, in the language of the dyer, is much better bled ; 
 but we considered this to result from softening the particles of wood, and 
 so making the colouring matter more easily dissolved by the water after- 
 wards applied. Whether anything more is effected by the practice 
 noticed by Mr. Parkes, or if any decomposition takes place, we cannot 
 say. If by fermentation is meant the formation of acids, we know that 
 acids do not produce the effects stated ; but if it is a fermentation caused 
 by the decomposition of any substance having nitrogen as a constituent, 
 the result would be the formation of ammonia, a substance, as we have 
 already noticed, which has a powerful influence upon the colouring matter 
 
 s 
 
274 
 
 LOGWOOD. 
 
 of logwood, and extracts it very rapidly — -a property possessed, indeed, by 
 all alkalies and alkaline earths. This is well known to dealers in logwood, 
 who occasionally sprinkle it with water containing a little lime, which gives 
 the wood a richness in colour, thereby making the poorest woods, thus 
 doctored , appear equal to those of the finest quality. Such wood, however, 
 never produces good light shades. The presence of an alkali may be 
 detected in logwood by taking a little in a tumbler, and allowing it to 
 steep for a few hours in distilled water, and then trying the solution with 
 delicate test-papers. 
 
 This practice of putting lime-water upon the ground logwood may 
 be one reason why decoctions of ground logwood lose their colouring 
 power so rapidly on standing; as all alkaline matters in connection with 
 logwood, although they give to it, in the first place, a richness of colour, 
 it soon passes into a brown, and the colour decays. 
 
 There is yet no simple and accurate process for testing logwood which 
 could be introduced to the dye-house, although there are few substances 
 of apparently greater variety. The differences, however, often consist 
 only in the moisture and in the doctoring. 
 
 The method generally adopted for judging the value of logwood con- 
 sists in comparimg the colour of samples of yarn dyed by different specimens 
 of it. A given weight of each of the logwood samples is macerated in 
 boiling water, and then an equal quantity of mordanted cotton is dyed by 
 each of the several decoctions: the depth and kind of colour produced is 
 the test of the quality. With care this method is very satisfactory for 
 practical purposes ; but an oversight is often made in these trials in not 
 taking into account the quantity of water which is in the sample. It is 
 necessary that ground logwood should be a little damp, to prevent part of 
 it flying away as dust, but it is also requisite to avoid paying for the water 
 put into it at the same rate as for logwood.; care ought therefore to be 
 taken not only to dry the samples, but also to ascertain the water con- 
 tained in them. This will be rendered more apparent by stating the 
 results of some experiments directed to this point. Samples of wood, as 
 imported, before being ground or chipped, kept at a temperature of 212°, 
 as long as they decreased in weight, gave a loss ranging from 9 to 16 per 
 cent. — average 12 per cent. The moisture in ground logwood, as supplied 
 to the dyer, ranges from 38 to 46 per cent.— average 42 per cent. ; so that 
 the amount of water added or absorbed averages 30 per cent. 
 
 The amount of moisture may be tried by putting a weighed sample of 
 the ground wood upon a piece of paper, or on a plate for some hours in 
 the drying-stove, when no wet goods are in it. In the experiments, of 
 which the results are given above, we used a water-bath, which is pre- 
 ferable. Samples to be tried ought all to be previously submitted to the 
 drying process. 
 
 Water is not the only thing added to logwood: a little lime is occa- 
 sionally added to the water, which gives the logwood a bloom, and makes 
 it appear better than it really is. In burning samples of ground logwood, 
 
LOGWOOD. 
 
 275 
 
 and deducting the water that had been added, we have found the ash to 
 vary from 2 to 2-3 per cent. 
 
 When the usual mode of testing is followed, by trying the depth of 
 colour with a doctored sample and one not doctored, say half an ounce 
 of each, the ground wood in each case put into a small basin, and filled 
 with boiling water, and tl^e decoction used to dye a skein of cotton, the 
 doctored sample will be found to yield its colour immediately to boiling 
 water, and the other slower — in which case, the former having yielded all 
 its colour at once, may give a deeper dye than the other, and yet actually 
 contain less colouring matter. The proper way of proceeding is to take 
 100 grains of each sample, put each quantity upon a filter, and pour 
 boiling water upon them as long as the water passing through is coloured, 
 then use each liquor with cotton so mordanted as to take up all the 
 colour. The remaining logwood thus exhausted should be nearly colour- 
 less ; and by drying and weighing them, an approximation to the quantity 
 of colour may be obtained. Good logwood loses about 12-5 per cent 
 after deducting all water. 
 
 The following will illustrate our remarks, and the rules followed by 
 the dealer: — 
 
 A sample of Campeachy, Honduras, and Jamaica logwoods, ground 
 and raised, as supplied to the dyer, put into the water bath lost in drying — 
 
 Honduras, 
 
 36 per cent. 
 
 Campeachy, 
 
 . 22 „ 
 
 Jamaica, .... 
 
 33 ,, 
 
 Taking the samples as received, including the water, and extracting soluble 
 
 by boiling water, they gave — 
 
 Honduras, 
 
 13-5 per cent. 
 
 Campeachy, .. 
 
 . 15-5 „ 
 
 Jamaica, .... 
 
 13-0 „ 
 
 But giving each wood the same quantity of added water and comparing the 
 
 results, they stand thus : — 
 
 Honduras, 
 
 15*7 per cent. 
 
 Campeachy, 
 
 . 15-5 „ 
 
 Jamaica, .... 
 
 . 14-6 „ 
 
 Mordanted samples of cloth dyed by the wood as received shewed 
 Campeachy the best, Honduras next, and Jamaica worst; but when dyed 
 with the same weight of the dried samples Honduras was best, Campeachy 
 next. 
 
 These remarks and experiments apply less or more to all the ground 
 dye-woods. 
 
 We have already referred to the plumb tub and plumb spirits, and 
 stated that if a salt of tin be put into a hot solution of logwood, there is a 
 
276 
 
 BRAZIL-WOODS. 
 
 precipitate formed. If the neutral salt of tin be added to’ logwood cold, 
 there is a precipitate formed of a beautiful wine colour; but this precipi- 
 tate is soluble in dilute muriatic acid — hence the reason why so much acid 
 is used for the tin in the preparation of the plumb spirits. (See Spirits.) 
 
 The plumb tub is prepared as follows : — A decoction of logwood is 
 made by boiling, continuing the ebullition until the specific gravity is 8° 
 of Twad. This decoction is allowed to stand till it is perfectly cold; a 
 quantity of tarry matter precipitates in the cooling, so that the clear liquor 
 requires to be decanted. There is then added to it a quantity of plumb 
 spirits , sufficient to raise the specific gravity to about 14° of Twad. 
 After standing twenty-four hours, it is fit for use — which consists simply 
 in immersing the goods for a short time, then taking them out and wash- 
 ing them. As this compound of tin and logwood is held in solution by 
 the free acid of the spirits, whenever the cotton impregnated with it 
 is put into water the dye is rendered insoluble ; repeated washing is 
 necessary to carry off all free acid. Occasionally, in preparing the plumb 
 tub , it happens from some cause, as want of care in making the spirits or 
 decoction, that the logwood gets all precipitated. This precipitate may 
 all, or the greater part of it, be dissolved by adding hydrochloric acid ; but 
 in this case the tint of colour produced upon the goods will not be so blue: 
 it will be more red, with a tendency to brown. Hydrochloric or nitric 
 acid added to a cold solution of logwood will make a plumb tub without 
 tin; but there being no base, and the solution being soluble in water, it 
 does not form a good dye, being nearly all removed by washing. But if 
 the goods be previously mordanted with a base, colours of various tints 
 may be obtained; this may be resorted to when a plumb tub is not at 
 hand. 
 
 Brazil-Woods. 
 
 Bois de Pernambouc of the French, and the Brazilienholz of the German 
 dyers. There are several varieties of this wood, which are distinguished 
 from each other by the name of the locality where they are obtained, 
 such as Pernambuco, Japan, &c. In the dye-house they are often 
 all named peach-wood , from an inferior sort often used and obtained 
 from Campeachy. 
 
 The Brazil-wood tree, called by botanists Csesalpinia crista , is an 
 American production, and, according to some authorities, gave the name 
 to the country in which it grows, Brazil. The Portuguese government 
 discovered the value of the wood, and made it an object of royal monoply; 
 hence it came by the now forgotten name of Queen-wood. It grows mostly 
 in dry places, and amongst rocks; its trunk is large, crooked, and full 
 of knots. 
 
 The following paragraph upon these woods is taken from Bell’s 
 Geography : — u The ibiripitanga, or Brazil-wood, called in Pernambuco the 
 pao da rainha (Queen’s-wood), on account of its being a government 
 monopoly, is now rarely to be seen within many leagues of the coast, 
 
BRAZIL-WOODS. 
 
 277 
 
 owing to the improvident manner in which it has been cut down by the 
 government agents, without any regard being paid to the size of the tree 
 or its cultivation. It is not a lofty tree. At a short distance from the 
 ground innumerable branches spring forth, and extend in every direction 
 in a straggling, irregular, and unpleasing manner. The leaves are small 
 and not luxuriant ; the wood is very hard and heavy, takes a high polish, 
 and sinks in water; the only valuable portion of it is the heart, as the 
 outward coat of wood has not any peculiarity. The name of this wood is 
 derived from brasas, a glowing fire or coal ; its botanical name is Ccesalpinia 
 brasileto. The leaves are pinnated; the flowers white and papilionaceous, 
 growing in a pyramidal spike ; one species has flowers variegated with 
 red. The branches are slender and full of small prickles. There are 
 nine species.” 
 
 The species brasileto is inferior to the crista ; it grows in great abun- 
 dance in the West Indies. The demand for this wood a few years ago 
 was so great, owing to its being a little cheaper than the other, that nearly 
 the whole of the trees in the British possessions were cut down, and sent 
 home, which Mr. Bell very justly terms improvidence. New colouring 
 matters have taken the place of Brazil-wood, so that it is not now so much 
 used, and is consequently scarcer in the market. 
 
 The wood known in commerce as Pernambuco is most esteemed, and 
 has the greatest quantity of colouring matter. It is hard, has a yellow 
 colour when newly cut, but turns red by exposure to the air. That kind 
 termed Lima-wood is the same in quality. Sapan-wood grows in Japan, 
 and in quality is next to the two named above. It is not plentiful, but is 
 much valued in the dye-house for reds of a certain tint : it gives a very 
 clear and superior colour. The quantity of ash that these two qualities 
 of wood contain is worthy of remark. Lima-wood as imported gives the 
 average of 2-7 per cent., while Sapan-wood gives only 1-5 per cent.: in 
 both the prevailing earth is lime. The quantity of moisture in the wood 
 averages about 10 per cent. That in the ground wood in the market 
 about 20 per cent. 
 
 Peach-wood , or Nicaragua, and sometimes termed Santa Martha-wood , 
 is inferior to the other two named, but is much used in the dye-house, 
 and for many shades of red is preferred, although the colouring matter is 
 not so great. It gives a bright dye. The means of testing the quality of 
 these woods by the dyer is similar to that described for logwood, with the 
 same recommendations and precautions. 
 
 The world is much indebted to the French chemists for their valuable 
 researches into the colouring matters of the dye-woods. M. Chevreul 
 long since obtained the colouring matter from Brazil-wood by the follow- 
 ing process: — “Digest the raspings of the wood in water till all the 
 colouring matter is dissolved, and evaporate the infusion to dryness, to 
 get rid of a little acetic acid which it contains. Dissolve the residue in 
 water, and agitate the solution with litharge, to get rid of a little fixed 
 acid which it contains. Evaporate again to dryness, digest the residue in 
 
278 
 
 BRAZIL-WOODS. 
 
 alcohol, filter and evaporate to drive off the alcohol. Dilute the residual 
 matter with water, and add to the liquid a solution of glue, till all the 
 tannin which it contains is thrown down; filter again and evaporate to 
 dryness, and digest the residue in alcohol, which will leave undissolved 
 any excess of glue which may have been added. This last alcoholic 
 solution being evaporated to dryness, leaves brezilin, the colouring matter 
 of the wood, in a state of considerable purity.” 
 
 Brezilin is very soluble both in water and alcohol, but from the hard- 
 ness of the wood the colouring matter is not completely extracted except 
 by boiling ; even the method recommended for logwood does not dissolve 
 all the brezilin. The decoction, when boiled, has a deep-red colour, but 
 passes into a rich yellow-red on standing. Acids give this solution a 
 yellowish colour, but render it unfit for dyeing operations. Alkalies com- 
 municate a violet colour, which is very fugitive : — 
 
 Protosulphate of iron, Dark purple, not changed by standing. 
 
 Persulphate of iron,. . Blackish-brown, permanent. 
 
 Chloride of tin, .. . Changes to a deep crimson. 
 
 Chloride of tin, . . With warmed liquor, a deep-red precipitate. 
 
 Acetate of copper, . Dark purple. 
 
 Since these researches by Chevreul, M. Preisser has investigated these 
 substances with great minuteness, and gives it as his opinion that the 
 colouring matter of these, as well as of the other woods, are oxides of a 
 colourless base. Thus brezilin is the oxide of a base which is without 
 colour, and which he terms brezilein* Their compositions are — 
 
 c. H. o. 
 
 Brezilein — Colourless base, . . . . = 18 14 12 
 
 Brezilin — Coloured substance, . .. . = 18 14 14 
 
 It will thus appear that the one is converted into the other by absorbing 
 two proportions of oxygen, and that the reactions are allied to those of 
 indigo and logwood, already described. 
 
 When a strong decoction of the colouring matter is allowed to stand 
 for some time, there is found a quantity of crystals of brezilein. These 
 have been carefully tested, and a formula somewhat different from the 
 above has been proposed — namely, C 22 H 2 oO;:. In the crystalline state it 
 contains two equivalents of water ; like the colouring matter of logwood, 
 it combines with oxygen under the influence of ammonia, and gives definite 
 compounds. Some of these reactions may be made available in calico- 
 printing. 
 
 The action of chromic acid and of the chromates upon brezilin is 
 remarkable : they decompose each other, and produce a beautiful reddish- 
 brown. The action of bichromate of potash with the decoction of Brazil- 
 wood has been long taken advantage of in calico-printing, and by proper 
 modifications may also be applied in the dye-house. The remarks upon 
 the pure colouring matter are applicable to the decoction of the wood; but 
 
SANTAL OR SANDAL WOOD. 
 
 27D 
 
 the wood contains other matters (small portions of astringent substance), 
 which are also soluble in the water, and which accordingly modify to a 
 great extent the results produced by the combined action of the decoction 
 and the pure colouring principle — a circumstance which should be con- 
 stantly borne in mind by the dyer. It is known that decoctions of Brazil- 
 wood improve by standing, often to the extent of giving a half more 
 effect as a dye, which is supposed to be owing to the oxidation and deposi- 
 tion of the tannin and other foreign matters injurious to the colour. 
 
 The nitrates of the metals almost all destroy the red colour of Brazil- 
 wood, turning it into a dirty yellow. The salts of potash, soda, and am- 
 monia change the decoction into a rose colour, which soon passes away on 
 standing. Alum throws down a bulky red precipitate. This substance 
 and the chloride of tin are considered the proper mordants for Brazil- 
 wood ; but all the colours obtained by this wood are exceedingly fugitive, 
 losing their brilliancy on a short exposure to air. The sun has a very 
 powerful influence upon colours dyed by this wood. By a short exposure 
 the red colour assumes a blackish tint, passes into a brown, and fades 
 away into a light-dun colour. These changes are supposed to arise from 
 the colouring matter being decomposed into water and some other volatile 
 substance, leaving a part of the carbon free, which produces the black ; 
 heat is also very destructive to this colour ; nevertheless, the consumption 
 of this species of wood is very great, especially for dyeing what are termed 
 fancy reds upon cotton. 
 
 Santal or Sandal- Wood, 
 
 Commonly called saunders-wood , is a native of the East Indies. It 
 differs from Brazil-wood in many of its properties; it is very hard, and 
 gives but a weak decoction in water. The colouring matter of this wood 
 is different from that of Brazil-wood. 
 
 The opinion of chemists who have studied the colouring matter of this 
 wood is that it contains two colouring substances — one in the younger and 
 paler-coloured wood, the other in the old dark-coloured wood, which 
 contains more oxygen. The colouring matter is termed santaline ; its 
 composition is given as C 15 H 14 0 5 , or C 30 H 26 O 10 . The young wood, 
 by standing, becomes darker from absorbing oxygen. The wood seems to 
 have several other colouring matters in it not yet investigated. 
 
 Alumina gives red precipitates with santaline, which have more of a 
 violet tint than those of brezilin; but it does not react in the same manner 
 with the chromates. Santaline is much more soluble in solutions of the 
 astringent substances than in water, and is therefore boiled along with 
 sumach, and is frequently used for woollens in dyeing browns and other 
 mixed colours containing red. According to the investigations of the 
 French chemists, this wood is a variety of bar wood, at least the colouring 
 matter is of the same composition. 
 
280 - 
 
 BARWOOD. 
 
 Barwood. 
 
 This wood is brought principally from Sierra Leone. Its colouring 
 matter has been examined by MM. Girardin and Preisser, who considered 
 it the same as santaline. MacCulloch, in his Commercial Dictionary , makes 
 a distinction between barwood and camwood ; but they are found to be the 
 same in chemical composition, only coming from two different places. 
 
 The following is MM. Girardin and Preisser’s description of this 
 wood : — 
 
 “ This wood, in the state of a coarse powder, is of a bright-red 
 colour, without any odour or smell. It imparts scarcely any colour to the 
 saliva. 
 
 “ Cold water, in contact with this powder, only acquires a fawn tint 
 after five days’ maceration ; 100 parts of water only dissolve 2-21 of sub- 
 stances consisting of 0-85 colouring matter and of 1-36 saline compounds. 
 Boiling water becomes more strongly coloured, of a reddish -yellow, but 
 on cooling it deposits a part of the colouring principle in the form of a 
 red powder. 100 parts of water at 212° dissolve 8*86 of substances, con- 
 sisting of 7*24 colouring principle and 1*62 salts, especially sulphates and 
 chlorides. On macerating the powder in strong alcohol, the liquid almost 
 immediately acquires a very dark vinous-red colour. To remove the whole 
 of the colour from 15 grains of this powder, it was necessary to treat it 
 several times with boiling alcohol. The alcoholic liquid contained 0*23 of 
 colouring principle and 0*004 salt; barwood contains, therefore, 23 per 
 cent, of red colouring matter, whilst saunders -wood, according to Pelletier, 
 only contains 16*75. 
 
 “ The alcoholic solution behaves in the following manner towards 
 re-agents : — 
 
 great quantity. Produces a considerable 
 
 Distilled water, added in 
 
 Fixed alkalies 
 
 Lime-water 
 Sulphuric acid . 
 
 Sulphide of hydrogen 
 Salt of tin . 
 
 Chloride of tin . 
 Acetate of lead . 
 
 yellow opalescence. 
 The precipitate is re- 
 dissolved by the fixed 
 alkalies, and the liquor 
 acquires a dark vinous 
 colour. 
 
 Turn it dark crimson or 
 dark violet. 
 
 Ditto. 
 
 Darkens the colour to a 
 cochineal red. 
 
 Acts like water. 
 
 Blood-red precipitate. 
 
 Brick-red precipitate. 
 
 Dark violet gelatinous 
 precipitate. 
 
BARWOOD. 
 
 2S1 
 
 Salts of the protoxide of iron 
 
 Copper salts, 
 
 Chloride of mercury, . 
 
 .Nitrate of bismuth 
 
 Sulphate of zinc, 
 
 Tartar-emetic, 
 
 Neutral salts of potash 
 Water of barytes, 
 
 Gelatine, .... 
 
 Chlorine .... 
 
 . Very abundant violet 
 precipitates. 
 
 . Violet-brown gelatinous 
 precipitates. 
 
 . An abundant precipitate 
 of a brick-red colour. 
 
 . G i ves a light and brilliant 
 crimson-red. 
 
 . Bright-red flocculent 
 precipitate. 
 
 . Abundant precipitate of 
 a dark cherry colour. 
 
 . Act like pure water. 
 
 . Dark violet-brown pre- 
 cipitate. 
 
 . Brownish-yellow ochre - 
 ous precipitate. 
 
 . Brings back the liquor 
 to a light yellow, with 
 a slight yellowish - 
 brown precipitate, 
 resembling hydrated 
 peroxide of iron. 
 
 “ Pyroxylic spirit acts on barwood like alcohol, and the strongly- 
 coloured solution behaves similarly towards re-agents. Hydrated ether 
 almost immediately acquires an orange-red tint, rather paler than that 
 with alcohol. It dissolves 19-47 per cent, colouring principle. Ammonia, 
 potash, and soda, in contact with powdered barwood, assume an extremely 
 dark violet-red colour. These solutions, neutralised with hydrochloric 
 acid, deposit the colouring matter in the form of a dark reddish-brown 
 powder. Acetic acid becomes of a dark-red colour, as with saunders-wood.” 
 
 The difficulty of its slight solubility in water is overcome by a very 
 ingenious arrangement. The colouring matter while hot combines easily 
 with the proto-compounds of tin, forming an insoluble rich red colour ; 
 the goods to be dyed are impregnated with protochloride of tin combined 
 with sumach ; the proper proportion of barwood for the colour wanted is 
 put into a boiler with water and brought to boil ; the goods thus impreg- 
 nated are put into this boiling water containing the rasped wood, and the 
 small portion of colouring matter dissolved in the water is immediately 
 taken up by the goods. The water thus exhausted dissolves a new portion 
 of colouring matter, which is again taken up by the goods, and so on, till 
 the tin upon the cloth has become, if we may so term it, saturated ; the 
 colour is then at its brightest and richest phase. 
 
 A good deal of attention and skill is necessary to know the exact point 
 to take the goods out of the bath, otherwise the dyer may either have the 
 
282 
 
 CAMWOOD. 
 
 colour poor, or, by being in too long, give it a brown colour. It is not 
 therefore every dyer who can dye good barwood red. 
 
 In dyeing with this wood it must be in contact with the goods : the 
 particles of the wood must mix with the fibre. To have the wood in a bag 
 even does not answer ; and therefore great care is necessary in putting the 
 mordanted goods into the dyeing bath, that there be no loose mordant 
 upon them ; for if there is, the wood (being in the bath) will take up this 
 mordant and become dyed, and so retain a corresponding portion of the 
 colouring matter, and to that extent cause loss. Inattention to this pre- 
 caution is, moreover, frequently the cause of great irregularity in the 
 shades; and even with the greatest care the wood-grounds come out of the 
 bath richly dyed. Barwood is not used along with other matters for com- 
 pound colours in the same way as the other red woods are for dyeing 
 cotton; but it is occasionally so used in dyeing woollens. The dyer has 
 no means of testing the value of this dyewood, owing to its insolubility in 
 water. In a piece of wood, as imported, we found moisture 11 per cent., 
 and only 0-5 per cent, of ash. In ground samples the moisture averages 
 about 20 per cent., and the ash 1-2. The colouring matter is very soluble 
 in dilute ammonia. By passing ammonia water through a weighed quan- 
 tity upon a filter, until all soluble matters are dissolved out, then drying 
 the residue, the average of good barwoods gives — 
 
 Lost, water at 212°, 18-2 
 
 Colouring matter, . . . . . . . 8*4 
 
 Wood remaining, 734 
 
 100-0 
 
 By neutralising the ammonia, the colour is precipitated as a lake. 
 
 It is recommended in some works upon dyeing, as a general rule, that 
 as all colours that are dyed in boilers by having the wood and fibre 
 together, the fibre begins to take on the dye when the solution is luke- 
 warm ; therefore the goods should be put in at that heat, and kept in till 
 the proper depth of colour is got. This may be best in the case of 
 woollen, and is necessary with some colours, such as barwood and madder, 
 upon cotton ; but it is not good as a rule for cotton. Generally, indeed, 
 the quicker cotton is dyed the better; and especially when there is a mix- 
 ture of colouring matters used, long working causes that colour which has 
 the greatest attraction for the mordant to prevail at the expense of the 
 others, even although the attraction when the goods were newly put into 
 the mixture may have been simultaneously equal and mutual. 
 
 Camwood 
 
 Is another species of red wood imported from Sierra Leone, and some- 
 times used in the dye-house. Its colouring matter is more soluble than 
 that of barwood or saunders -wood, and is more allied to brezilin, and the 
 colour obtained from it is more permanent, and in many instances much 
 
FUSTIC OR YELLOW- WOOD. 
 
 283 
 
 more beautiful than those termed Brazil-woods. The precipitates from a 
 decoction of this wood are more yellow than those afforded by the Brazil- 
 woods, which explains why the colours dyed by it have a certain degree 
 of richness not obtained with the other woods. It is not so easily affected 
 by alkaline substances, and appears to contain more tannin than the 
 Brazil-woods. With it — 
 
 Gives a brownish-black precipitate. 
 
 A reddish-brown. 
 
 Give the solution a very bright carmine- 
 red colour, but little precipitate. 
 
 A rich orange precipitate, after standing 
 some time. 
 
 Protosulphate of iron 
 Persulphate, . . 
 
 Protosalts of tin . . 
 
 Lead salts, . . . 
 
 Acetate of copper, 
 
 Mtrate of silver, . . A reddish-yellow precipitate. 
 
 Perchloride of mercury, Light orange by standing. 
 
 Alum Gives the solution a beautiful red colour. 
 
 It is used for wool more than for cotton, and may be used for browns 
 and other composition colours where Brazil-wood is used ; or as a sub- 
 stitute for many other purposes in which the best Brazil-woods are 
 employed. 
 
 Fustic or Yellow- Wood. 
 
 This dye-stuff has been long known. It is uncertain when it was 
 introduced as a dye-drug, but mention is made of it in a book published 
 in 1692. The botanical name of the tree which produces this drug is 
 Morus tinctoria. It grows spontaneously in Brazil, and in several of the 
 West Indian islands, where it attains to a great height. The wood is of a 
 sulphur colour, with orange veins, and contains two colouring matters — 
 the one resinous, and not soluble in water ; the other very soluble in this 
 menstruum, producing a deep yellow colour, having a light orange cast. 
 This substance has been long used for dyeing yellow, is still extensively 
 employed for producing that colour upon woollen and silk, and is the 
 principal ingredient in dyeing greens upon these substances ; but it is now 
 seldom used for these colours on cotton. 
 
 The colouring matter of this wood has been studied by M. Chevreul, 
 who has given it the name of morin. If we take 1 lb. of ground fustic and 
 boil it for a short time in a gallon of distilled water, and then pass the 
 solution rapidly through a filter to separate the woody particles, as the 
 solution cools it becomes turbid, and a quantity of the colouring matter is 
 precipitated. If allowed to stand for several days, a goodly quantity of 
 morin may be obtained in a crystalline form. Every practical dyer who 
 has used fustic knows that if his decoction of this wood stands over it loses 
 its colouring properties, and that therefore it should be used immediately 
 
284 
 
 YOUNG FUSTIC. 
 
 after boiling. The yellow decoction of this wood gives, with the following 
 re-agents, — 
 
 Alkalies, 
 
 Protochloride of tin, 
 Perchloride of tin, 
 Alum, 
 
 Acetate of lead, 
 Acetate of copper, 
 Protosalts of iron, 
 
 Persalts of iron, 
 Sulphuric acid, . 
 Nitric acid, 
 
 An orange colour with a green tint. 
 
 A reddish-yellow. 
 
 A rich yellow. 
 
 A canary yellow. 
 
 An orange -yellow, but dirty. 
 
 A brown tint. 
 
 A greenish-olive tint, which darkens by 
 standing. 
 
 The same. 
 
 A red precipitate by standing. 
 
 A red precipitate. 
 
 The morin precipitated from the solution is soluble in water with 
 difficulty, but dissolves freely in a weak alkali, from which it may be pre- 
 cipitated. The colouring matter is often found crystallised in veins of the 
 wood. The base of this colouring substance is also considered to exist in 
 the white state, but it passes into yellow by absorbing oxygen. Its com- 
 position is C 12 H 8 0 5 ; the wood also contains a tannic acid, Ci8H 16 O 10 , 
 or C 13 H 10 O 6 H 2 O, which gives green precipitates with salts of iron, and 
 gives it a value in the dye-house for olives and green tints. 
 
 This dyewood was partially superseded for the dyeing of yellows upon 
 cotton by quercitron bark, and both are now almost totally displaced by 
 bichromate of potash and lead in the dyeing of cotton. There are still, 
 however, some greens dyed by fustic upon cotton yarn. The yarn is first 
 dyed blue by the blue vat, and then passed through a little pyrolignite of 
 alumina ; it is next wrought in a hot decoction of fustic, which commu- 
 nicates a beautiful rich shade of greeiu 
 
 Light cotton fabrics, such as gauzes and muslins, are also occasionally 
 dyed green by fustic. For this purpose the wood is used in the same 
 manner as the quercitron bark. Fustic is also used with other woods for 
 compound shades, as drabs, fawns, olives, &c., and is much used with 
 logwood in dyeing black, both on cotton and upon silks and woollens. 
 
 Young Fustic, 
 
 Called also Venetian sumach , was long used in France under the name 
 of fustet , for giving a yellow dye. These names caused a good deal of 
 confusion, which is to some extent obviated by the prefix young to this 
 wood, the yellow-wood being old fustic. Young fustic is a shrub (Rhus 
 cotinus') which grows principally in Italy and the south of France, where it 
 is cultivated for the purposes of dyeing. When cut down it is stripped of 
 its bark and broken into small pieces, in which state it is met with in com- 
 merce. This wood contains a large quantity of yellow colouring matter, 
 
BARK OR QUERCITRON". 
 
 285 
 
 named fusteric. It is soluble in water, and in that state gives the following 
 reactions with other substances : namely, with — 
 
 Tin salts, 
 
 Iron salts, . 
 Acetate of lead, . 
 Alkalies in solution 
 
 An orange-yellow precipitate. 
 An olive-green colour. 
 
 A yellowish -white. 
 
 Change the colour to red. 
 
 This colouring matter has a strong attraction for oxygen, a property 
 which affects its use as a dye. The colours being fugitive, it is seldom 
 used alone, but as an assistant to enable the dyer to obtain some particular 
 tint. It is not used in cotton dyeing. 
 
 Bark or Quercitron 
 
 Is the inner bark of a tree (the Quercus nigra of botanists) which 
 grows native in North America. Its dyeing properties were first made 
 known to the public by Dr. Bancroft in 1784, and were very soon 
 appreciated. Two years after he obtained an Act of Parliament vesting in 
 him the exclusive use and application of it for a certain term of years. 
 
 A decoction of quercitron bark has a yellow-orange colour. If the 
 decoction be made very strong, it deposits a portion of the colouring 
 matter in cooling. It contains a great quantity of tannin, which is always 
 dissolved in the decoction, and which gives the solution of bark a greater 
 variety of uses. A decoction of the bark gives the following reactions 
 with other matters : — 
 
 Alkalies 
 
 Lime, 
 
 Protochloride of tin, . 
 Alum, 
 
 Acetate of alumina, . 
 Acetate of lead, 
 Acetate of copper, 
 Salts of iron, 
 
 Hydrochloric acid and 
 nitric acid, 
 
 Deepen the colour of the solution. 
 
 A precipitate of a yellowish-red colour. 
 
 A yellowish -red precipitate. 
 
 A slight precipitate cold, but more when 
 hot. 
 
 A bulky reddish-yellow precipitate. 
 
 A reddish -yellow precipitate. 
 
 A greenish-yellow precipitate. 
 
 Dark olive -green precipitates, passing into 
 brown. 
 
 Reddish-yellow precipitates. 
 
 The pure colouring matter of bark has been extracted and investigated 
 by Chevreul and Bolley. It is termed quercitrine, is a crystalline substance 
 of a sulphur-yellow colour, and, like the other extractive colouring matters, 
 is considered to be the oxide of a colourless base. The composition of 
 quercitrine was given as follows : — 
 
 Carbon. Hydrogen. Oxygen. Water. 
 
 8 8 9 1 
 
286 
 
 BARK OR QUERCITRON. 
 
 But this substance having been further studied, these elements are arranged 
 by the chemists in a different way, the yellow colouring matter (quercitrine) 
 is now considered C2 7 H 18 0 12 . 
 
 A decoction of bark standing until it becomes stale loses much of its 
 dyeing properties. The yellow matter is deposited, and what remains in 
 solution is of a darker hue, and gives a dull colour when used for 
 dyeing. 
 
 This was extensively used in the dye-house for many years for the 
 purpose of dyeing yellow, and almost completely superseded the use of 
 fustic, both from its beauty and also its cheapness; but its use for that 
 purpose on cotton has been superseded by the bichromate of potash. Its 
 principal use in the cotton dye-house is to form the ground for certain 
 browns, and for dyeing green upon light muslin cloth ; but catechu has 
 nearly superseded it for browns. The quantity of tannin combined with 
 it makes it very useful for olives ; goods impregnated with iron, and passed 
 through a decoction of bark, take a beautiful olive. When used for dyeing 
 green, the mordant employed is acetate of alumina ; but for yellow, which 
 is only dyed upon yarn for particular purposes, the mordant used is 
 chloride of tin (spirits). 
 
 When bark is used for brown upon yarns, the goods are dyed a 
 deep yellow by being steeped in sumach, and then passed through the 
 spirits, out of which they are wrought in a boiling decoction of bark, 
 raised with spirits — that is, having a quantity of spirits put into the 
 bark solution. The goods are washed from this, and afterwards passed 
 through a mixture of logwood and Brazil-wood, according to the shade of 
 brown required. And we would here draw attention to a very interesting 
 fact, observed first by Mr. Thom of Manchester — namely, that amongst 
 the colouring matters and bases there is an elective affinity, which, if not 
 studied, will lead to several errors. We quote on this subject from 
 Parnell’s Applied Chemistry : — 
 
 “ But the combinations of alumina, &c., with soluble colouring matters, 
 seem to be cases of true chemical combination, taking place in definite 
 proportions, and under the influence of different degrees of attractive 
 force for different colouring principles. Thus, alumina has a stronger 
 attraction for the colouring principle of madder than for that of logwood, 
 and a stronger attraction for that of logwood than for that of quercitron. 
 When a piece of cloth impregnated with alumina is immersed in a decoc- 
 tion of quercitron bark, it acquires a fast yellow colour ; if the same cloth 
 is washed for some time and kept in a hot decoction of logwood, the 
 alumina parts with the colouring principle of quercitron to combine with 
 that of logwood, and the colour of the cloth becomes changed from yellow 
 to purple. If the same cloth is next immersed for a few hours in a hot 
 infusion of madder, the alumina parts with the colouring principle of log- 
 wood to unite with that of madder, the colour of the cloth changing from 
 purple to red. The quantity of alumina on the cloth does not appear to 
 diminish while these substitutions are taking place. These interesting 
 
FLAVINE. 
 
 287 
 
 facts were communicated to me by Mr. John Thom of the Mayfield print- 
 works.” 
 
 Now the same law is applicable when the mordant is tin; so that a 
 quantity of goods having been dyed yellow, as described, and then put 
 into a hot solution of logwood, a portion of the yellow is displaced by the 
 colouring matters of the logwood and Brazil-wood. Every dyer knows, 
 when he wants browns of a deep shade, how difficult it is to bring them 
 up should he fail to strike the proper tint at the first dip; if he is neces- 
 sitated to continue working in the logwood and Brazil-wood, he is very 
 apt to run his colour poor in yellow by dissolving it off ; and to remedy 
 this evil he next adds fustic or bark, with very questionable success. We 
 have often experienced these difficulties when dyeing browns upon cloth by 
 the process described above, with an aluminous mordant instead of tin. 
 
 Flavine. 
 
 Several years ago a vegetable extract bearing this name was introduced 
 into the arts, and is still in use ; it is brought from America in the state of 
 an impalpably fine powder, very light, and of a dun colour. It is used in 
 the dye-house as a substitute for quercitron bark, and for some pur- 
 poses is superior to it, giving a brighter colour. The mode of preparing 
 it for dyeing is by dissolving it in hot water, which gives a sort of 
 turbid solution. It should be used when newly dissolved ; for, if allowed 
 to stand, it deposits a brownish -yellow mass, in consequence of its not 
 being all completely soluble in water. If boiled in distilled water until all 
 the soluble matter is taken up, and the clear solution decanted, it soon 
 yields a deposit. The colour produced by flavine is never good until 
 raised. A colour dyed by it weakens gradually when a little sulphuric 
 acid has been added, or when put through a weak sour ; but what colour 
 remains retains its brilliancy by raising, and in respect of this property it 
 differs from bark. 
 
 The quantity of colouring matter in flavine is very great : its value as 
 compared with bark is as 16 to 1, or 1 oz. flavine is equal to 1 lb. of bark. 
 A sample burned left 4*4 per cent, of ash ; it is occasionally adulterated 
 with common salt. A solution of it gives the following reactions with 
 salts : — 
 
 Persalts of irofi, . 
 Protosalts df iron, 
 Protosalts of tin, 
 Persalts of tin, . 
 Alumina, 
 
 Olive-black precipitates. 
 
 Deep greenish-black precipitates. 
 Lemon-yellow precipitates. 
 Orange-yellow precipitates. 
 
 A rich yellow precipitate. 
 
 Acids lighten the colour of the solution, and alkalies deepen it, 
 rendering it redder. 
 
288 
 
 WELD OR WOLD. 
 
 A sort of English flavine has been patented in this country and in 
 Germany. It is prepared by boiling a strong decoction of bark with 
 dilute sulphuric acid, which seems to remove the tannin without affecting 
 the colouring matter of the bark, by which means a brighter yellow is 
 obtained. The colouring matter is deposited, well washed and dried, and 
 sold to the dyer in a powdered state. It requires a boiling heat to dye 
 with this substance. 
 
 Weld or Wold. 
 
 This vegetable is extensively cultivated in France and many other 
 parts of Europe for the purposes of dyeing yellow. It is found in com- 
 merce in small dried bundles. The more slender the stem is, the better is 
 it considered for dyeing. Both the seeds and the stems are used, as they 
 both contain the colouring matter ; but the seeds are considered to contain 
 it in greatest quantity. The colouring matter approaches very nearly to 
 that of quercitron in chemical properties ; and of all the vegetable dyes, it 
 is least acted upon by acids and alkalies — which gives to the dye, so far as 
 these substances are concerned, great permanence. But it has this coun- 
 teracting disadvantage, that the colour rapidly fades or passes away when 
 exposed to the action of air and light ; it then becomes oxidised, and in 
 consequence has been abandoned for almost all purposes where bark can 
 be used. It is still, however, occasionally used as a yellow dye for silks 
 and woollens, and also for some mixed colours. A decoction from weld 
 is made in the same way as that of most other vegetable dyes ; the wood, 
 whether in bunches or chipped, is merely put into a boiler with water and 
 boiled. Sometimes the bunches are put into a bag of coarse cloth and 
 thus boiled. This decoction is of a yellow colour, with a reddish tint, 
 has a bitter taste and a-pe.culiar odour. 
 
 Alkalies 
 Acids . 
 
 Alum, . 
 
 Protochloride of tin, 
 Acetate of lead, . 
 Sulphate of iron, . 
 
 Change it to a brighter yellow. 
 Barken the yellow. 
 
 A yellow precipitate. 
 
 A yellow precipitate. 
 
 A yellow precipitate. 
 
 A yellowish-olive precipitate. 
 
 The colouring matter of this dye has been obtained in needle-shaped 
 crystals by sublimation, and is termed luteoleine. Its composition is 
 given as C 20 H 14 O 8 . We have referred to a use to which weld is applied 
 m the making up of pastel and woad vats (page 259). The weld was long 
 used as a dye for woollen and silk before it was used for cotton ; its 
 introduction as a dye for this substance is connected with a clever fraud. 
 “ In the year 1773, the sum of £2,000 was granted by Act of Parliament to 
 a Br. Williams, as a reward for his discovery of a fast green and yellow 
 
PERSIAN BERRIES. 
 
 289 
 
 dye upon cotton yarn and thread. This supposed fast dye was given by 
 the combination of weld with a certain mordant, the composition of which 
 the patentee was permitted to conceal, that foreigners might not enjoy the 
 benefit of his discovery, while he on his part engaged to supply the cotton 
 and thread dyers with his dye at a certain fixed price. The mordant used 
 was supposed by chemists to be a solution of tin alone, or of tin and 
 bismuth, which gives to weld yellow the power of resisting the action 
 of acids and of boiling soap-suds, although it is not proof against the 
 continued action of the sun and air. This defect, however, was not easily 
 discernible, in consequence of the ingenious method which, according to 
 Dr. Bancroft, the inventor employed to obtain a favourable testimony of 
 the dyers upon the subject. He caused his specimens of dyed yarn to be 
 woven into pocket-handkerchiefs, and gave them to he worn in the pockets 
 of those who were afterwards to attest to the goodness of his dye ; and as 
 handkerchiefs worn in pockets were not exposed to the action of the sun 
 and air, this want of permanence was not discovered until some time after 
 the reward had been paid for an invention which proved of little or no 
 value.” 
 
 Turmeric. 
 
 This is another substance formerly used in dyeing. It is principally 
 brought from the East Indies and from China. It is the roots of a plant 
 named Curcuma langa, resembling ginger ; it is reduced to powder, and 
 in this state is met with in the market. The colouring matter is extracted 
 by boiling in water ; and decoctions of it have a peculiar smell and bitter 
 taste. The colour is very fugitive, fading rapidly in the air ; and there is 
 no proper mordant for it. We have occasionally seen it used for giving 
 a peculiar tint to greens and light browns ; but this only lasted for 
 a short time. The colouring principle of this vegetable has also been 
 extracted, and is known chemically under the name of curcumine. A 
 decoction of turmeric, or paper dyed with it and kept from exposure, is 
 much used in testing for the presence of alkalies, which give to the dye a 
 red-brown colour. 
 
 Persian Berries. 
 
 These berries form the root of the Rhamnus tine tor ia, a plant growing in 
 the Levant and south of France. They yield a bright-yellow colour, used 
 by artists and occasionally by dyers ; but the dye is very fugitive. There 
 are two kinds of Persian berries ; one large, plump, and clear in colour, 
 the other small, wrinkled, and brown. The colouring matter of each kind 
 has also certain distinctive properties, caused, it is believed, by the one 
 being in full maturity, the other unripe. The large and mature berries are 
 
 T 
 
290 
 
 SAFFLOWER OR CARTHAMUS. 
 
 the best, giving a greater quantity of dye, and of superior quality of 
 colour. The colouring matters extracted from the two varieties are named 
 hyrso-rhcimnine and xantho-rhamnine. These have some interesting reac- 
 tions with bichromate of potash, and other oxidising agents. This dye is 
 still used in certain operations in the print-works, but not in the ordinary 
 dye-house. 
 
 Safflower or Carthamus. 
 
 This is an annual plant cultivated in Spain, Egypt, India, and the 
 Levant. There are two varieties of it, one having large leaves, and the 
 other smaller ones ; the latter is the better. It is only the flower of this 
 plant that is used for dyeing. When the flowers are gathered, they are 
 squeezed between two stones to express their juice ; they are afterwards 
 washed with spring water, next taken in small quantities and pressed 
 between the hands and laid out upon mats to dry. The cakes thus formed 
 are covered up during the day to prevent the sun from shining upon them, 
 which would not only destroy the colour, but dry the cakes too much, 
 and thereby cause further deterioration. They are kept exposed to the 
 dews of night, and turned over occasionally, till dried to the proper 
 point, when they are packed up for the market. It is in this state 
 they are procured by the dyer. This dye has been known from the 
 earliest ages. 
 
 Safflower is found to contain three colouring substances. Two 
 are yellow, one of which is very soluble in water, the other in alkalies ; 
 neither is of use to the dyer. To free the safflower from these yellow- 
 colouring substances is an essential part in the manipulation of this dye- 
 stuff. The other colouring substance is red, and is extracted from the 
 vegetable by means of alkaline carbonates, after the first yellow sub- 
 stance has been washed away. This red substance is used very exten- 
 sively for dyeing the various shades of pinks, crimsons roses, &c., 
 upon silk, and also for the same colours upon cotton, and for lavender, 
 lilac, pearl-white, &c. The mode of preparing safflower for the pur- 
 pose of extracting the red matter from it was for a long time that 
 recommended by Berth ollet, and followed by all other writers upon the 
 subject — namely, putting a quantity into a fine bag, “tramping” it with 
 the feet in water until the yellow colour was dissolved and washed away ; 
 the mass left was then treated with an alkali to extract the red matter. 
 But although this red colouring matter is insoluble in water, it was found 
 that the bag in which it was. tramped became a deep crimson-red, which 
 could only be produced by its imbibing this red matter. It proceeds, 
 we think, from a very fine powder, probably carthamine, adhering to the 
 stuff like the pollen of the flower, and which floats away in the water. It 
 is much heavier than the ordinary carthamine, and collects as a sediment 
 
SAFFLOWER OR CARTHAMUS. 
 
 291 
 
 at the bottom of the vessels used to hold the safflower ; but when tramped 
 in bags, this powder is expressed and imbibed by the bag, which becomes 
 strongly dyed, thereby causing a loss of the dye. To avoid this, the saf- 
 flower is now put into a tub without any bag, with as much water as will 
 cause the whole to float freely. A very little pressure or agitation is 
 sufficient to reduce the cakes to a soft flocculent mass, which was the sole 
 use of tramping. It is next removed to a cask or tub, provided with a 
 false bottom, covered with fine haircloth. In the lower or true bottom is 
 a plug-tap. This vessel is filled with clean water, which is let out by the 
 plug at the bottom ; it is filled again, and so on, until the water passing 
 through is not coloured yellow. After this, there is put into it a measured 
 quantity of pure water — about three gallons to the pound of safflower— 
 in which is dissolved a little carbonate of soda, or carbonate of potash 
 (pearlash does well), about an ounce to the pound of safflower. Some 
 kinds require less than others ; but care ought to be taken that too much 
 is not used, as it destroys the brightness of the colour. It is well 
 stirred, and allowed to stand for about seven hours ; the plug is then 
 taken out, and the clear liquor drawn into a proper vessel. This liquor 
 contains the yellow and red dye which has been extracted by the alkali . 
 The remaining safflower is afterwards washed by pouring upon it a little 
 more water made slightly alkaline, and allowing it to steep a short time ; but 
 if fine light colours are to be dyed directly from the solution, this second 
 extract does not answer so well, as the shade is not so pure. This second 
 extract is commonly kept and used instead of clear water for the next 
 parcel of safflower ; and if it is wanted for this purpose, a little acid is added 
 to the liquor, and a piece of old cotton is allowed to steep in it until it has 
 extracted all colouring matter, — this is afterwards recovered for use, as 
 will presently be described. 
 
 The liquor extracted from the safflower contains both red and yellow 
 colouring matter. For this reason silk goods are not dyed directly by this 
 extract, as the silk takes up a portion of the yellow, which renders the 
 colour more of a brick hue than is wanted in the rose and pink. To dye 
 silks, any old cotton yarn is dyed first by the safflower extract ; the cotton 
 takes up nothing except the red. This cotton is then thoroughly washed 
 in cold water till the water coming from it is perfectly clear ; it is then 
 steeped for a little in water made slightly alkaline by carbonate of soda or 
 potash, which extracts the red from the cotton, and forms the dyeing solu - 
 tion for silk. The silk to be dyed pink generally receives a bottom or ground 
 by passing it through a weak solution of cudbear or archil, so as to form 
 a flesh or light lavender colour, the depth being regulated according to the 
 shade of pink wanted. It is then put through the safflower solution, 
 which must previously be rendered acid by a little lemon-juice, vinegar, 
 or sulphuric acid. When the safflower liquor is exhausted, the silk is 
 washed in cold water, and finished by passing through a little water made 
 acid by lemon-juice or tartar ; neither vinegar nor sulphuric acid should 
 be used in the finishing process. 
 
292 
 
 SAFFLOWER OR CARTHAMUS. 
 
 To dye cotton pink the liquor is used as extracted from the vegetable ; 
 the goods require no previous preparation, except to be well bleached. 
 The quantity of liquor used varies according to the shade required ; one 
 pound of safflower to the pound of cotton gives a dark rose, and the other 
 shades in proportion, according to the tint required. 
 
 The goods are first wrought in the alkaline solution for five or six 
 minutes and then taken out, and vitriol added to the solution until it 
 tastes decidedly sour ; the goods are again immersed and kept working in 
 this till the solution is perfectly exhausted. The ascertaining of this point 
 requires a little experience, as exhaustion is known by the operator holding 
 a little of the liquor between him and the light, when, if there is no tinge 
 of red, the solution is spent. The goods are now to be well washed in 
 cold water; they are then finished by passing them through a little water, 
 with just sufficient tartar to make the liquid taste sour. 
 
 It must be borne in mind that in dyeing cotton with safflower, the 
 water ought to be pure, and always cold : a very little heat destroys the 
 beauty of the colour ; the goods ought also to be dried cold, and preserved 
 carefully from sunshine. The colours obtained by safflower are the prettiest 
 and clearest that can be had upon cotton, but they are fugitive. 
 
 The most beautiful lilacs, puces, and lavenders are obtained by safflower 
 and Prussian blue; but it is one of the most difficult colours to produce of 
 equal shade. The goods are generally first dyed a blue by nitrate of iron 
 and prussiate of potash (see page 99), and then put through the safflower 
 solution, previously made acid; but the rapidity with which the cloth 
 takes up the red renders it almost impossible to get a perfectly even dye. 
 Another method is to dye the cloth in the first instance pink, and then to 
 dye it blue. This method gives a more equal dye, but it is liable to 
 serious objections. The nitrate of iron used acts upon the colouring 
 matter, oxidising and destroying its beauty and depth, thus causing loss, 
 and making this colour' exceedingly expensive. Persulphate of iron may 
 be used instead of the nitrate, as it is not so corrosive, and will preserve 
 the tint of the safflower much better. Copperas and red prussiate are 
 preferable to either. 
 
 We mentioned in our introductory remarks that one essential condi- 
 tion in all dye-drugs, before they could be used as such, was that they 
 should be in solution; but carthamus is an exception to this rule: when it 
 is in a soluble state it is not a dye, and must be rendered insoluble before 
 it will act as such. Although the cotton is generally passed through the 
 alkaline solution before acid is added, still this will not produce the dye, 
 but merely secures an equalised colour under the rapid action with which 
 the fibres imbibe the solid colouring matter after acid is applied. 
 
 This fact favours the opinion that the cotton imbibes the colouring 
 matters in the same way as they are imbibed by charcoal, the fibres of the 
 cotton, like those of silk and wool, being hollow. (See page 87.) 
 
 This action is not merely a capillary attraction, such as shewn with 
 glass tubes. When very small glass tubes are placed with their ends dipping 
 
SAFFLOWER OF CARTHAMUS. 
 
 293 
 
 into a solution, the fluid is observed to rise in them to a considerable height 
 inversely as the hollow diameters of the tubes, and then remain stationary ; 
 if such tubes are placed in a vessel filled with water containing the carthamus 
 in suspension, although they become filled with the liquor, they do not 
 exhaust it of the suspended colouring matter; whereas the fibres of the 
 cotton, placed into this fluid, extract all the colour- 
 ing matter from the water, and become literally 
 filled with it. Thus, if we take a vessel filled with 
 water, having in it carthamus rendered insoluble by 
 an acid, and suspend a skein of cotton in it for a 
 few hours, the cotton will absorb the whole colour- 
 ing matter, and leave the solution clear, indicating 
 thereby a distinct power of attraction exercised 
 between the fibre and colouring particles, and also 
 a circulation of the fluid through the fibre or tubes 
 of the cotton, which, indeed, is true, more or less, of any solid substance 
 so finely divided as the carthamus, and diffused in water along with fibres 
 of cotton. In the case of precipitates, the more dense they are the 
 smaller is the quantity of solid matter imbibed by the fibre. 
 
 When a little safflower solution has an acid put into it, and is allowed 
 to stand for a time, the red carthamine precipitates as a fine red lake, and 
 is sold as such, adhering to saucers, for dyeing ribbons, &c. 
 
 Although safflower colours may be the most simply and easily dyed of 
 all others, still, from their delicate reactions with other matters, there are 
 few substances subject to so much risk of being destroyed. If the water 
 is not pure, they will dry brown. A little acetic acid, cream of tartar, or 
 tartaric acid, is generally added to the last water from which they are 
 finished to preserve the tint; but too much or too little of these will pro- 
 duce perceptible effects upon the shades. Great care has to be taken in 
 drying : it should be done in a perfectly dry stove, not hot, and having 
 ample space between each parcel, as a very little steam produces a yellow 
 surface. The goods are generally dried in the cold; but care is necessary 
 that no sun-rays touch them, also that they are not injured by steam or 
 smoke entering the sheds where they are drying. If all necessary precau- 
 tions are not taken, the dyer has the mortification, as well as expense, of 
 putting the goods through at least the last acid solution again, and if 
 they are much touched, he is obliged to re-dye them. 
 
 The view that carthamine, or the red colouring matter of safflower, 
 is the oxide of a colourless base, as in the case of the woods we have 
 referred to, has been objected to by many investigators, whose experi- 
 ments and reasoning bear evidence of care and judgment; thus adding an 
 interest to the subject of vegetable colouring matters, and shewing the 
 practical man that there is yet before him much to be discovered, and that 
 a careful observation of all the reactions and circumstances connected with 
 his operations will stand a fair chance of being rewarded with discovery. 
 
 The composition of carthamine is given as Ci 4 H 16 07. 
 
294 
 
 LEVANT MADDER. 
 
 Madder. 
 
 Madder has been known as a dye-drug from the earliest times. The 
 red upon the cloth wrapping Egyptian mummies is found to have been 
 dyed with madder. This vegetable rivals indigo or any other vegetable 
 substance as a dye-drug, both from the beauty and permanence of the 
 colours it produces, and also from the variety of shades which it is capable 
 of furnishing by the combinations of its colouring matters. It is the root 
 of a plant or shrub called Rubia tinctorum , cultivated in the Levant and in 
 several western countries of Europe, especially in France and Holland. 
 The East Indies also furnish a quantity of it ; there is a large importation 
 from there of a species termed Rubia munjista , which contains more 
 colouring matter than the best madders of Europe. Its culture has been 
 often attempted in England, but without success. In the Levant the 
 madder is collected only once in five years, but in France it is gathered 
 every three years. It is only the root of the plant that is used for dyeing. 
 In removing the root from the ground it is carefully cleaned, and, when 
 the season is favourable, it is spread out in the air to dry. French madder 
 is generally more imperfectly dried than that from the Levant, and conse- 
 quently contains more water of vegetation, and to that extent it is com- 
 paratively less valuable. It is sometimes dried in stoves to allow it to 
 pulverise. The dryness of the article is judged of by the fracture when 
 a piece of the root is broken transversely by bending it. 
 
 When the roots are perfectly dry, if they are broken or cut with a 
 knife, they present to the eye a reddish -yellow colour, which passes to a 
 dense brownish-red when the piece is moistened ; but the more yellow the 
 root appears when dry the more colouring matter does it yield. Madder, 
 when fresh, and after being cut or ground to powder (in which state it is 
 generally used by the dyer), has a heavy sweet smell, with a somewhat 
 earthy flavour. The products of grinding are generally of three kinds. The 
 first is formed of the epidermis, or skin of the roots, and comes off in fine 
 filaments by slight pressure. This is collected separately, and forms what 
 is termed the mull, which is of very inferior quality. The second consists 
 of the annular portion of the root, and the third of the ligneous or centre 
 portion, generally these two qualities are mixed. 
 
 The varieties of madder in commerce are distinguished by the name 
 of the country from whence they are brought, and by the appearance they 
 possess in the preparatory process through which they pass previous to 
 their reception at the dye-house. 
 
 Levant Madder is in the form of shoots or fibres, of greater or less 
 length, and very slender ; brown externally, and pale orange-red inter- 
 nally. It is merely cleaned of earth and dried, and is imported from 
 Smyrna, Cyprus, &c. 
 
MADDER OF AVIGNON. 
 
 295 
 
 Dutch Madder is ground, but so very coarsely as to enable the buyer 
 to judge of the nature of the root from which it is prepared. It has a 
 greasy feel, and a strong nauseous odour. Its colour varies from a brown 
 to an orange-red; the brown is inferior. It becomes damp when exposed 
 to the air — a property which can be taken advantage of to judge of its 
 quality: “ if a little of it is exposed in a damp place when good, its colour 
 passes from the brownish -orange tint to a deep red.” 
 
 The madder of Holland is said to be cropped or uncropped , according 
 as the barky matter of the root is separated or not from the ligneous part 
 in the process of pounding through which it passes. This madder is never 
 employed fresh, but is kept at least a year, and it is better to be kept three 
 years before it is used. It may be kept several years longer without being 
 impaired. During the first years it is kept it undergoes some internal 
 change, and becomes much brighter in colour ; the powder adheres to- 
 gether, forming a mass very difficult to remove from the cask, and swells 
 so that the bottom of the cask often assumes a convex form. If kept for 
 too long a time it becomes deteriorated: the portion in contact with the 
 cask loses its brilliancy, and becomes brown, and this change gradually 
 extends through the whole mass. After this change has taken place it is 
 unfit for dyeing fine reds or light tints, and can be used only for dark 
 colours. 
 
 The marks of Dutch madder are— 
 
 Alcase Madder. — This madder is met with in commerce in a state 
 very similar to that of Dutch madder ; but although the operation of 
 cropping is generally performed upon it, that term is not used in desig- 
 nating it. It readily absorbs moisture from the air, and also acquires a 
 deep-red tint when exposed in a damp atmosphere, such as that of a cellar. 
 Like Dutch madder, it is not employed fresh : it is in its best condition 
 when kept about two years, but it deteriorates much sooner than the 
 Dutch by keeping, and also agglomerates into a mass and swells. It is 
 inferior to the madder of Holland ; its odour is more penetrating, and its 
 taste less sweet , but with an equal degree of bitter ; its colour is more 
 yellow, passing into brown, with much less of the orange tint. A little 
 experience in comparing the two sorts soon enables the dyer to distinguish 
 the one from the other. 
 
 Madder of Avignon. — This madder is deservedly much esteemed. 
 There are several varieties of it, some due merely to the modes of pre- 
 paration, and others to the soil on which the plant grows. It is ground 
 into a fine powder, which feels dry to the touch, and does not absorb 
 moisture so readily as the other kinds of madder ; but when exposed to a 
 humid atmosphere, it also undergoes a change. Its odour is very agree- 
 
 Mull O, 
 Superfine, 
 
 oupernne, . . or 
 
 Cropped or uncropped, j 
 
296 
 
 MADDER OF AVIGNON. 
 
 able ; the taste a mixed sweet and bitter, the last predominating ; and its 
 colour varies from a pink or rose hue to a deep red or reddish-brown. The 
 best qualities are obtained from those roots which grow in marshy or 
 swampy ground, and places enriched by admixture of animal or vegetable 
 matters. The roots from such a soil are generally of a deep-red colour, 
 while those from less favourable grounds are of a rose or pink tint. It is 
 by mixing these kinds in different proportions that the variety of madders 
 from this locality are obtained. The several qualities have various marks, 
 besides the ordinary marks, as — 
 
 P. to signify 
 
 R. 
 P. P. 
 R. P. P. 
 
 
 Palus (marshy). 
 
 Roseate. 
 
 Pure palus (marshy). 
 Purest red palus (marshy). 
 
 The actual commercial marks, according to the order of their quality, 
 are — 
 
 S. F. for superfine — containing all the matter of the root. 
 
 S. F. F. iov fine superfine — containing all the ligneous matter of 
 the root, the mull or bark or outside portion being 
 separated. 
 
 E. S. F. F. for extra fine fine — containing the heart or centre of 
 the root, and the internal part of the oily ring which 
 surrounds it; being also twice sifted so as to separate 
 completely from the mull, &c. 
 
 These three varieties may themselves vary according to the nature of 
 the roots and the manner in which they have been dried and otherwise pre- 
 pared ; but it is from these that all the various mixtures are made, and the tact 
 of the manufacturers consists in mixing them so as to produce the qualities 
 required by the consumer. 
 
 Avignon madder can be used fresh, although it is better to be kept for 
 twelve months. It does not cake or agglomerate in the cask, but when 
 kept too long it becomes deteriorated in quality, undergoing the same kind 
 of decomposition as the other madders. 
 
 Madder is often adulterated by mixing with it brick-dust, red or 
 yellow ochres, sand, and clay, or by adding sawdust of certain woods, as 
 mahogany, logwood, sandal- wood, &c. The mineral adulterations may be 
 detected by putting some of the suspected madder in a large glass vessel, 
 and adding to it a quantity of pure water — the madder floats, and the 
 mineral adulterations sink to the bottom. We thus readily obtain an 
 approximate idea of the quantity of adulterating matters present, and by 
 carefully removing the floating madder, and then filtering the liquor, the 
 mineral substances may be separated and weighed. We may also proceed 
 by burning a small portion of the madder, and seeing the ash that remains: 
 we have in this way tried various samples, having 8|- per cent, of ash. 
 
 When the adulterants consist of sawdust or other ground vegetable 
 matters, their detection is much more difficult; indeed, the only means 
 
MADDER OF AVIGNON. 
 
 297 
 
 likely to be at all successful is to weigh a portion of the suspected madder, 
 and to try its colouring powers with a piece of prepared cotton : except where 
 chemical skill can be applied, the colouring matter of the madder can be 
 extracted and compared with other known qualities. 
 
 Some of the French dyers use a colorimeter for judging of the quality 
 of their madder. It depends upon a principle similar to that of Mr. Crum’s 
 chlorimeter for testing the strength of bleaching powder (see page 67). A 
 weighed quantity of madder of known quality is boiled, and the decoction 
 is put into a glass vessel; similar quantities of the madders to be tried are 
 treated in the same manner, and placed in glass vessels of similar size and 
 form, and the tint of colour is judged by comparison. Of course the test 
 solution may be diluted by a measured quantity of water, and by using a 
 graduated glass their comparative values, estimated by the rate of dilution, 
 &c., may be easily ascertained. But this method is subject to many errors, 
 as when any adulteration has been practised on the madder, by addition of 
 other vegetable colouring matters, such as sapan-wood, &c. 
 
 Madder has been the subject of more extensive chemical investigations 
 than any other dye-drug, extending over a period of fifty years, and they are 
 still incomplete. The first investigation into the chemical properties of 
 madder led to the discovery of two distinct colouring matters — one 
 yellow, which is very soluble in cold water, and named xanthin ; the 
 other red, moderately soluble in hot water, and called alizarin. The 
 most simple method proposed for extracting alizarin was — “ One pound 
 weight of madder is mixed up with an equal weight of concentrated 
 sulphuric acid, and the vessel closed up and allowed to stand in a cool 
 place for three or four days : by this process all the constituents of 
 the madder are converted into charcoal, except the alizarin. When this 
 charring process is completed, the mixture is carefully washed and dried, 
 and then digested in alcohol, which dissolves the alizarin and leaves 
 the charcoal. The solution may now be diluted with water, and 
 
 put into a retort, and kept at a heat of 170° Fah. : the beak of the retort 
 being connected to a receiver, the alcohol distils over, and is recovered. 
 Water and alizarin remain in the retort, which being poured out and 
 filtered, - the alizarin remains upon the filter in a state of great purity. 
 It is of a beautiful red colour, and gives the same colour to boiling water.” 
 
 Alizarin is soluble in alcohol, turpentine, naphtha, and fat oils ; chlorine 
 turns it into a yellow-brown ; sulphuric acid dissolves it, and, at the same 
 time, enlivens the colour; muriatic and nitric acids both dissolve it, 
 changing the colour from red to yellow. 
 
 Alkalies, . . . .A violet colour. 
 
 Alumina, . . . .A deep red-brown precipitate. 
 
 Oxides of tin, . . . Precipitates of the same appearance. 
 
 Phosphates have a very powerful attraction for alizarin ; so much so, 
 that when animals take any madder into their system, the bones, which 
 
298 
 
 MADDER RED. 
 
 contain a large quantity of phosphates, become coloured red. This fact 
 is well known to dyers who are in the habit of using madder in their 
 operations, and necessarily often tasting it. When taken in quantity, the 
 urine is coloured by it. 
 
 From the above reactions of alizarin with other substances, it was 
 supposed that it constituted the true colouring of madder; and means 
 were soon adopted to separate this colouring matter from the vegetable, 
 and use it pure ; but it was afterwards found that a fixed dye could not 
 be obtained by pure alizarin, and therefore it did not constitute all that 
 was required in giving the dye. This led to further investigations, pro- 
 ductive of further discoveries respecting these colouring matters, which led 
 to the conclusion that madder has five different colouring matters, which 
 have been named — 
 
 Madder purple, I Madder orange, 
 
 Madder red, I Madder yellow, 
 
 Madder brown, 
 
 each of which may be obtained by the following operations : — 
 
 Madder Purple. — The madder is washed in water at about summer 
 heat, then boiled in a strong solution of alum for an hour ; the clear liquor 
 is afterwards decanted, and sulphuric acid added, which precipitates the 
 madder purple along with a number of impurities. These are removed by 
 washing with boiling water, then with pure muriatic acid, and afterwards 
 dissolving in alcohol. Madder purple is soluble in hot water ; and if pure 
 it gives the water a dark-pink colour. If the water contains lime, a great 
 part of the colouring matter is precipitated as a reddish-brown substance. 
 Cotton saturated with the acetate of alumina is dyed a bright red, pro- 
 vided the quantity of madder purple be not too great for the aluminous 
 base ; if so, the colour will have more of a purple tint. A boiling solution 
 of alum forms with the madder purple a cherry-red solution ; caustic 
 potash forms with it a fine yellowish-red colour ; the carbonate of potash 
 and soda have a similar effect ; and sulphuric acid produces a bright red 
 or rose colour. 
 
 Madder Red is separated from madder purple in consequence of its 
 not being soluble in a strong solution of alum. It is obtained by boiling 
 madder in a weak solution of alum, by which a reddish-brown precipitate 
 is obtained. This precipitate is separated, and boiled in pure muriatic 
 acid, then washed carefully with water, and boiled in alcohol. This 
 dissolves both madder red and madder purple ; but by gently evaporating 
 the alcoholic solution until it is very much concentrated, and then allowing 
 it to cool, an orange-coloured precipitate is formed, which is collected and 
 repeatedly boiled in a strong solution of alum, as long as the alum solution 
 comes off coloured : the insoluble portion is madder red. It is a yellowish - 
 brown powder, and imparts to cotton, impregnated with acetate of alumina, 
 
MADDER ACIDS. 
 
 299 
 
 a dark-red colour when the colour is in excess ; but if the mordanted cotton 
 be in excess, a brick-red colour is produced. Caustic potash gives a 
 violet, carbonate of soda a red, and sulphuric acid a brick-red solution. 
 
 Madder Orange is distinguished from the two former colours by its 
 slight solubility in alcohol. It is prepared by macerating madder for 
 twenty-four hours in distilled water, the infusion being strained off and 
 allowed to repose a few hours. The liquor is carefully decanted and fil- 
 tered through a paper filter, upon which the madder orange remains. It 
 may be washed with cold water, and afterwards purified by spirits of wine, 
 in which it is not soluble. It is a yellow powder, soluble in boiling water, 
 and imparts to cotton impregnated with an aluminous mordant a bright- 
 orange colour when in excess. A boiling solution of alum forms with 
 madder orange a yellow solution ; caustic potash gives a dark rose, car- 
 bonate of soda an orange, and sulphuric acid an orange-yellow colour. 
 
 Madder Yellow is characterised by its great solubility in water. It 
 is a yellow gummy mass, communicates to mordanted cotton a pale 
 nankeen colour, but does not of itself form a true dye. Madder which 
 contains much of this ingredient is of inferior quality, as the yellow 
 becomes so incorporated with the other colours, as materially to deteri- 
 orate them, and to require several operations to free the goods from it 
 afterwards. 
 
 Madder Brown is a brownish-black dry mass, obtained in the pre- 
 paration of the other colouring matters. It is neither soluble in water nor 
 alcohol, is of no importance as a dye-drug, and does not enter into any 
 of the colours dyed by madder. 
 
 Madder Acids. — Besides these five colouring matters, there were 
 obtained two acid substances, named madderic and rubiacic acids. They 
 have no known dyeing properties, and are only mentioned here to shew 
 the development which chemical research produced ; indeed, so important 
 were any investigations in madder considered, that the Societe Industrielle 
 de Mulhouse for several years offered 2,000 francs as a premium for the best 
 analytical investigation of this substance. 
 
 More recently, extensive investigations have been made upon the 
 constitution of the different colouring and other substances found in mad- 
 der, by Mr. Higgins and Dr. Schunck and others. According to the last 
 named chemist, the madder root contains several distinct substances — 
 viz., a bitter principle, which he called rubian , which by decomposition 
 yields two colouring matters, alizarin and rubiacin, besides several other 
 products not colours. Alizarin he considers the only true dyeing principle 
 of madder root; and it is considered that alizarin does not exist ready- 
 formed in the growing root, but is the result of the decomposition of the 
 rubian; hence, perhaps, the reason why the full colouring power of the 
 
300 
 
 MADDER PREPARATIONS. 
 
 root is not developed until after the madder has undergone a partial 
 fermentation. Schunck dissolves out the soluble matter from the root 
 with water, and decomposes the solution by boiling it with dilute acid, 
 when the whole of the colouring portion is precipitated, including the 
 alizarin. If this precipitate be boiled with water, the alizarin is dissolved, 
 and the rubiacin and some resinous matters are left. The composition of 
 alizarin is given by Dr. Schunck as C 14 Hio0 4 , by some others it is given 
 as C 10 II 6 O 3 2H 2 0. Artificial alizarin is given as C 14 H 8 0 4 . We refer 
 the reader for details of their elaborate researches into the composition 
 of madder to the Pliil. Trans., 1851, 1853, 1855. Notwithstanding these 
 researches, which have been productive of great good, practically it is only 
 necessary to consider madder as containing no more than two colouring 
 matters, as was formerly supposed, and as not contradicted by recent research 
 — viz., the dun or yellow, which constitutes the impurity of the madder, 
 and which the dyer endeavours to get rid of, and the red colouring 
 matter. The former, or yellow, does not combine with the cloth alone, and 
 probably not at all, but it has a strong affinity for the other colouring 
 matters, and combines with them when they are upon the cloth, and has 
 to be separated from them by after processes. The red, which is a com- 
 bination of the red and the purple, unites with the cotton, and is known to 
 the dyer only in the aggregate state. This colouring matter is difficultly 
 soluble in water, and therefore no strong decoction of it can be obtained 
 by boiling, so that it is not very applicable for compound colours, and 
 therefore of little avail in the fancy dye-house. Many extensive fancy 
 dyers, indeed, do not consider madder as even belonging to their pro- 
 vince. They use it very seldom, except to give a peculiar tint to some 
 light compound colours, and for fast salmon colours, pinks, &c. When 
 deep colours are to be dyed by madder, the goods must be put into the 
 dye-bath or boiler along with the madder, in a way nearly similar to that 
 described for barwood. 
 
 Madder in the hands of the skilful operator can be made to produce a 
 vast variety of colours and tints, by corresponding changes of mordants, 
 and the colours are all characterised by a degree of permanency which no 
 other vegetable dye-wood produces. The operations, however, are gene- 
 rally much more tedious than those for ordinary fancy colours ; and 
 much skill is also required in preparing and applying the proper mordants 
 for madder colours, and also in the preparation of the cloths for the 
 different mordants. 
 
 Madder Preparations. — It has been already stated that madder roots 
 contain a variety of compounds besides the colouring matters, such as 
 glucose, or certain varieties of sugar, which is extracted by means of steep- 
 ing. The madder is ground and mixed with water, about a gallon to the 
 pound of madder, and allowed to steep in this for a day. Sometimes a little 
 sulphuric acid is added to make the water sour and so dissolve out any 
 lime. This water is let off, and caught, and allowed to ferment, and 
 
MADDER T REPARATIONS. 
 
 301 
 
 there is obtained by this means a large quantity of alcohol. The madder 
 thus freed from all soluble matter is dried and ground fine, sent into 
 the market, and sold under the name of madder bloom, or flower of 
 madder, &c. 
 
 Another preparation which has now come into general use is garancine. 
 A variety of methods have been proposed for this preparation, founded 
 upon the fact that alizarin, or the principal colouring matter of madder, 
 is neither destroyed nor soluble in strong sulphuric acid. The madder roots 
 are ground or reduced to a coarse powder, and treated with hot sulphuric 
 acid for eight or ten hours ; the whole is then put into a large tank, having 
 a false bottom covered with flannel, the liquor is let off and retained for 
 making alcohol, &c., the solid is washed with water until all acid is 
 removed, when it is pressed and dried, and then ground fine and sent to 
 market. In these operations care should be taken that the sulphuric acid 
 is free from nitric acid, and that the water used is pure. Hydrochloric 
 acid is sometimes used instead of sulphuric, the process otherwise being 
 the same. 
 
 Madders after being used by dyers have also been treated in the same 
 way for garancine, in order to concentrate any remaining colouring matter 
 in the roots. Different patents have been taken out in this country 
 for this purpose. When the dyer has finished the dyeing of the goods, 
 the contents of the boiler are let into a tank having a filter at bottom, the 
 liquid being previously acidulated with vitriol to precipitate any soluble 
 colouring matter; the contents of the filter are subjected to pressure, and 
 afterwards treated with vitriol or muriatic acid, as described above, and 
 sent to market. Garancine made from this waste madder is much inferior 
 to that made from pure roots ; still there is a considerable portion of 
 colouring matter recovered which may be used along with good garancine. 
 The spent madder, after dyeing Turkey reds, treated as described, yields 
 little or no garancine, probably owing to the use of blood in this dye, 
 for albumen, as already stated, has a strong attraction for the colouring 
 matter of madder, and may thus exhaust the roots of colour. Whether 
 this be the cause or not, from a number of experiments we have tried 
 with spent madder from Turkey red, we have failed in obtaining any 
 available quantity of colour from it. 
 
 One hundred pounds weight of good madder roots should yield about 
 40 lbs. of garancine. Garancine is subject to several adulterations, and 
 varies considerably in quality. The best method of testing it, and one 
 which should be made before purchasing, is to take, say 10 grains of each 
 sample to be tried, and take an exact weight of cloth mordanted in stripes 
 for red, purple, black, &c., and dye these, and compare the results both 
 before and after clearing. A simple apparatus for this purpose is a copper 
 pan filled with water, into which is put the vessels containing the dyes 
 and samples, and heated by gas : bring the water in the copper vessel to 
 the boiling-point, and continue until the dyeing liquors in the different 
 vessels are exhausted. 
 
302 
 
 USEFUL PREPARATIONS. 
 
 The following is the action of garancine when put into different 
 qualities of water and with re-agents : — 
 
 Distilled water, cold , 
 
 Distilled water, boiling , . 
 
 Spring water, cold , 
 
 Boiling spring water, . 
 
 Cold lime water, . 
 
 Water with a little sulphuric acid, 
 
 Water with HC1, . . 
 
 Water with ITNQ 3 , 
 
 Water with acetic acid, . 
 
 Strong acetic acid . 
 
 Ammonia .... 
 
 Water with ammonia, 
 
 A solution of caustic soda, 
 
 Water with carbonate of soda, 
 Cold alum water, . 
 
 Boiling alum water, 
 
 A pale yellow in about 24 hours. 
 A pale reddish-yellow tint. 
 Less coloured than with cold 
 distilled water. 
 
 Less coloured than with boil- 
 ing distilled water. 
 
 Paler than with either cold 
 distilled or spring water. 
 Greenish - yellow tint after 
 some hours. 
 
 The same, but darker in tint. 
 Still darker tint, passing into 
 a brownish-blue. 
 
 Faintly yellow. 
 
 Acquires a beautiful reddish - 
 yellow colour. 
 
 ( Becomes red immediately and 
 < after a few hours so deep 
 ( as not to be transparent. 
 
 . Beautiful red colour. 
 
 . Dark red-brown. 
 
 . Bright reddish colour. 
 
 . Chrome-red colour. 
 
 . A dark-red colour. 
 
 The mordants used for dyeing with garancine are the same as for 
 dyeing with madder. It only yields its colour to the mordanted cloth, 
 at a boiling temperature, and the water of the bath or boiler does not 
 become coloured. A little sumach is often used along with the garancine 
 for reds. 
 
 If the water used in dyeing be from a calcareous spring, a little sul- 
 phuric acid, just enough to give the water a sour taste, should be added ; 
 but when sumach is used, the acid is not required. The dye obtained by 
 garancine is generally more brilliant and lively than from madder. In 
 printing the colour is not so liable to run upon the white, and the goods 
 are consequently more easily cleared than when madder is used. 
 
 The mordants used for madder are the acetate of alumina, acetate 
 of iron, and mixtures of these ; the chlorides of tin, acetate of lead, and 
 acetate of copper, and sometimes ammoniuret of copper. The last two 
 are often used as alterants. In using iron mordants it is of the utmost 
 consequence that they be the protosalts ; hence iron liquor is more fre- 
 quently used than sulphate of iron, which salt is more apt to become 
 peroxidised. 
 
ANNOTTA OR ARNOTTO. 
 
 OAO 
 
 30 o 
 
 Munjeet, or Mungeet. 
 
 Munjeet or Rubia munjista has been tried as a substitute for madder. 
 It contains more colouring matter, and is found in commerce in bundles, 
 consisting generally of thick and thin stalks; the thin stalked variety 
 contains less colouring matter than the thick, and has the bark on, 
 whereas the thick stalks are barked. The stalks of the munjeet are 
 very dry, light, and porous ; the fracture exhibits a congeries of empty 
 tubes. The powdered munjeet is composed of the thin and thick stalks 
 mixed. Dr. Stenhouse has made researches into the colouring matter 
 of this vegetable, and finds it differing from alizarin or purpurin, and 
 has given it the name of munjistin, and its composition is given as C 8 H 6 0 3 . 
 
 Reds dyed with munjeet are very brilliant, but fugitive, being de- 
 stroyed by a short exposure to light and air. This vegetable cannot, 
 therefore, be a proper substitute for madder. 
 
 Annotta, or Arnotto. 
 
 This substance, the Roucou of the French dyers, is obtained from a 
 shrub originally a native of South America, and now cultivated in Guiana, 
 St. Domingo, and the East Indies. It is termed the annotta tree, or Bixa 
 orellana , and seldom exceeds twelve feet in height. The leaves are divided 
 by fibres of a reddish-brown colour, and are four inches long, broad at 
 the base, and tending to a sharp point. The stem has likewise fibres, 
 which in Jamaica are converted into serviceable ropes. 
 
 44 The tree produces oblong bristled pods, somewhat resembling those 
 of a chesnut. These are at first of a beautiful rose colour, but as they 
 ripen, change to a dark-brown, and bursting open, display a splendid 
 crimson farina or pulp, in which are contained from thirty to forty seeds, 
 somewhat resembling raisin stones. As soon as they arrive at maturity 
 these pods are gathered, divested of their husks, and bruised. Their 
 pulpy substance, which seems to be the only part which constitutes the 
 dye, is then put into a cistern, with just enough water to cover it, and in 
 this situation it remains for seven or eight days, or until the liquor begins 
 to ferment, which, however, may require as many weeks, according to 
 circumstances. It is then strongly agitated with wooden paddles or 
 beaters to promote the separation of the pulp from the seeds. This 
 operation is continued until these have no longer any of the colouring 
 matter adhering to them ; it is then passed through a sieve, and afterwards 
 boiled, the colouring matter being thrown to the surface in the form of 
 scum, or otherwise allowed to subside : in either case it is boiled in coppers 
 till reduced to a paste, when it is made up into cakes and dried.” * 
 
 Another and preferable mode of extracting the colouring matter 
 from these seeds, is by rubbing them one against another under water, so 
 * Ann ales de Chemie, tome 47. 
 
304 
 
 ANNOTTA OR ARNOTTO. 
 
 that the mucilaginous and other impure matters contained in the interior 
 of the seed are not mixed. The colouring matter is allowed to settle, 
 the water drawn off, and the annotta left to dry. When prepared in this 
 manner, it has a fatty feel, is very homogeneous, and of a deep-red colour, 
 which changes to dark-brown on drying. It has no taste, but generally a 
 disagreeable smell, as brought into commerce. This smell, however, is 
 not natural, but is owing to stale urine having been added to it, in order to 
 improve its colour, and keep it moist. 
 
 The Caribbee Indians prepare the annotta, which they employ for 
 painting their bodies, by smearing their hands with oil, and then rubbing 
 the seeds until the pulp is separated in the form of a paste, which 
 adheres to their fingers, and which they remove with a knife and dry 
 in the sun. 
 
 Annotta of good quality is of a lively red colour when just taken from 
 the seeds, and before it has undergone any change. It was found by 
 Mr. John to contain the following ingredients 
 
 Colouring and resinous matters, 28-0 
 
 Vegetable gluten, . 26-5 
 
 Lignine, .......... 20*0 
 
 Extractive colouring matter, ...... 20-0 
 
 Matter resembling gluten and extractive, . . . 4-0 
 
 Aromatic and acidulous matters, . . . . . 1-5 
 
 100-0 
 
 Boiling water dissolves annotta, giving a thick decoction of a yellow 
 colour. Alkalies form with it a white precipitate, giving the liquor a clear 
 orange colour, which acids make redder. 
 
 Muriatic acid has no action upon annotta ; chlorine destroys its 
 colour. Nitric acid completely decomposes it, forming several compounds 
 which have not yet been sufficiently examined. Sulphuric acid poured upon 
 solid annotta gives it a deep-blue colour, not unlike indigo, but it soon 
 changes to a dark dirty-green, and then to a blackish-purple. 
 
 The colouring matters of annotta are easily soluble in alkalies, and in 
 this condition they are generally used in the dye-house. The alkali used 
 is either carbonate of soda or potash ; and when light shades upon silk 
 and fine cottons are wanted, soft soap is used. Sometimes a quantity 
 of annotta is prepared and kept as a stock liquor ; but this practice is bad, 
 as the liquor soon becomes stale, and loses a great portion of its dyeing 
 properties. It is best when newly prepared. A good method of prepara- 
 tion is the following : — Into a boiler, capable of containing 10 to 12 gallons 
 of water, are put 10 pounds weight of annotta, 2 lbs. of carbonate of soda, 
 and 2 lbs. of soft soap, and the mixture is boiled until the annotta is all 
 dissolved. 
 
 Cloth put into this solution is dyed a dark orange, but every shade 
 from an orange to a cream colour, can be dyed with it by merely using it 
 in a proper state of dilution with water. The cloth requires no previous 
 
ANNOTTA, OR ARNOTTO. 
 
 305 
 
 preparation ; but for fine light shades the colour is improved by dissolving 
 a little white soap in the water used for diluting it. The goods are merely 
 passed through the solution, and dried from it ; but where the colour is 
 strong, the cloth must be washed in water containing a little soap, to free 
 it from the strong alkali in the colouring solution. The addition of acids 
 turns the colours of cloths dyed by annotta to a yellowish-red, so that by 
 passing a piece of cloth dyed orange through water slightly acidulated 
 it assumes a scarlet or salmon colour, according to the quantity of colour- 
 ing matter used. But all the colours dyed by annotta are exceedingly 
 fugitive, and although neither acids nor alkalies can completely remove 
 the colours dyed by it, still they constantly change and fade by 
 exposure to the air and light. On this account annotta is now very 
 seldom used in the cotton dye-house, and when it is used it is only as 
 an auxiliary. It is, however, still used for silks and woollens, as the 
 objections to its use for cotton do not apply so strongly in relation to 
 those substances. It may also be used with propriety for mixed fabrics, 
 such as silk and cotton, silk and woollen, &c. 
 
 Annotta was considered to contain two distinct colouring matters — a 
 yellow and red — till it was shewn by M. Preisser that the one was the oxide 
 of the other, and that they may be obtained by adding a salt of lead to a 
 solution of annotta, which precipitates the whole colouring matter. The 
 lead is afterwards separated by sulphide of hydrogen; and the solution 
 being filtered and evaporated, the colouring matter is deposited in small 
 crystals of a yellow-white colour. These crystals consist of bixin : they 
 become yellow by exposure to the air, but by dissolving them in water 
 this change is prevented. This colouring matter has been formulated 
 variously, as C 5 H 6 0 2 , and also as C 12 H 22 0, so that it is probable there are 
 more colouring bases than one. The following are the reactions of bixin:— 
 
 Sulphuric acid gives . A yellow, which does not turn blue, 
 
 as it does with annotta. 
 
 Nitric acid, ... A yellow shade. 
 
 Chromic acid, . . A deep-orange tint. 
 
 When ammonia is added to bixin with free contact of air, there is 
 formed a fine deep-red colour, like annotta, and a new substance is pro- 
 duced, termed bixein, which does not crystallise, but may be obtained as 
 red powder ; this is coloured blue by sulphuric acid, and combines with 
 alkalies ; it is bixin with addition of oxygen. When annotta, in the form of 
 paste, is mixed from time to time with stale urine for its improvement, it is 
 more than probable that this improvement consists in the formation of 
 bixein from the bixin , by the ammonia of the urine. This is rendered the 
 more probable by finding the interior of the annotta yellow, while the red 
 colour is much more developed upon the surface where the air has free 
 access to it. This naturally suggests the mixing of annotta with a little 
 ammonia, and exposing it to the air as much as possible previous to its being 
 prepared for dyeing, as a much richer colour is thereby obtained. 
 
 u 
 
306 
 
 ARCHIL, OR ORCHIL. 
 
 The adulterations of annotta are oxide of lead and ochre. These may- 
 be detected by burning a small quantity of it in a china crucible : if pure, 
 no residue will be left ; but if oxide of lead be the adulterant, by keeping 
 the crucible at a red heat, a small button of lead will be obtained; and if 
 ochre be present, a red powder will be left. 
 
 The liquid sold in shops under the name of Scott’s Nankeen Dye is a 
 solution of annotta and potash in water. 
 
 Annotta is often used for colouring butter and cheese. 
 
 Alkamet Root. 
 
 This is the root of a plant (Lithos permum tinctorlum ) which grows in 
 the Levant and several other warm countries. It was introduced as a dye 
 some years ago, but with little success. The colouring matter is slightly 
 soluble in water, but is rendered soluble by alkalies, to which it gives a blue 
 colour, also by oils and fatty substances, which it colours red. It has the 
 following reactions : — 
 
 Salts of lead, 
 Salts of tin, 
 
 Salts of iron, 
 Salts of alumina, 
 
 . Blue precipitates. 
 
 ... Crimson precipitates. 
 
 . Violet-colour precipitates. 
 . Violet precipitates. 
 
 A variety of shades of lavender, lilac, violet, &c., are dyed by this colouring 
 matter, but caution and experience are necessary to ensure success, and the 
 colours obtained are easily affected by light — which, in our opinion, is the 
 greatest barrier to its use. Colours formerly were generally dyed with it 
 by giving the cloth an oil or soap preparation, the soap being combined 
 with alumina to serve as the base. Its use is now all but obsolete. 
 
 Archil, or Orchil. 
 
 This colouring matter is prepared from lichens, a species of sea-weed. 
 The most esteemed is that denominated Lichen rocella. The best sort comes 
 from the Canary and Cape de Verde islands ; but it is also found abundantly 
 on the coast of Sweden, Scotland, Ireland, and Wales, and the people have 
 from time immemorial used it for dyeing cloths. The colouring matters 
 prepared from these lichens have been long known in commerce in the 
 following forms : — 
 
 1. As a pasty matter, called archil. 
 
 2. As a red powder, called cudbear. 
 
 The details of the mode of preparing archil was long kept a secret, and 
 are but imperfectly known even yet. The lichens are first ground between 
 two stones to a pulp, with the addition of water, and afterwards put into a 
 
ARCHIL, OR ORCHIL. 
 
 307 
 
 wooden trough, having a tightly-fitted cover; upon the moist pulp is 
 sprinkled a mixture of urine and ammonia, and the vessel being then 
 covered, fermentation soon begins. The whole is occasionally stirred, and 
 more ammonia and urine are added from time to time. After a few days, the 
 colour begins to develop itself, but about six weeks are required to com- 
 plete the operation. The whole is then removed from the trough and 
 placed in casks, and may be kept for years. The keeping is considered to 
 improve the intensity of the colour, which should be of a deep reddish- 
 violet. 
 
 Within these few years, the colouring matters obtained from lichens 
 have been the subject of investigation by Dr. Stenhouse, Dr. Schunck, and 
 others, who have obtained a variety of interesting chemical products, some 
 of which give colours of various tints. In no case do the lichens contain 
 colours ready made, but they contain several colourless acids, which, under 
 the influence of alkalies and oxygen, produce new acid compounds and a 
 colourless neutral substance termed orcin, C 7 H 8 0 2 , which is the true 
 colour-producing body; under the influence of ammonia it absorbs oxygen, 
 and is converted into a substance termed orcein, C 7 H 7 NOg, which is the 
 colouring matter. Archil liquor is now prepared by digesting the lichens 
 in a hot solution of ammonia, allowing it to stand for a few hours, and 
 exposing the liquor drawn off in jars to the air for several weeks, and then 
 concentrating by evaporation. Cudbear is prepared by first freeing the 
 lichen as much as possible from earthy impurity, and then adding ammonia 
 and allowing the mixture to stand for several weeks exposed to the air, 
 keeping it moist with ammonia ; the whole is then converted into a paste, 
 which is afterwards dried and reduced to powder, andeonstitutes cudbear. 
 To give the dyer some idea of what has been already done, and the 
 various substances obtained from these lichens, we append a list, shewing 
 the formulae of composition, which will illustrate how small a change is 
 required to produce a distinct substance — 
 
 
 C. 
 
 H. 
 
 O. 
 
 
 Usnic acid, ..... 
 
 .19 
 
 16 
 
 7 
 
 
 Erythric, .... 
 
 . 20 
 
 22 
 
 10 
 
 
 Piero -erythric, 
 
 . 12 
 
 16 
 
 7 
 
 
 Erythrite, .... 
 
 4 
 
 10 
 
 4 
 
 
 Roccellinin, .... 
 
 . 18 
 
 16 
 
 7 
 
 
 Evernic acid, 
 
 . 17 
 
 16 
 
 7 
 
 
 Evernesic acid, 
 
 9 
 
 10 
 
 4 
 
 
 Lacanoric or orcellic acid, . 
 
 8 
 
 8 
 
 4 
 
 
 Orcellic or (lacanoric) ether, 
 
 . 10 
 
 12 
 
 4 
 
 
 Parellic acid, 
 
 9 
 
 6 
 
 4 
 
 
 Gyrophoric acid, . 
 
 . 36 
 
 36 
 
 15 
 
 
 Orcin, 
 
 7 
 
 8 
 
 2 
 
 H 2 0. 
 
 Beta-orcin, .... 
 
 . . 8 
 
 10 
 
 2 
 
 
 Orcein, .... 
 
 7 
 
 7 
 
 3 
 
 N. 
 
308 
 
 SOORANJEE. 
 
 The following is the action of various substances upon a solution of 
 archil or cudbear : — 
 
 Acids change the colour to 
 Alkalies ,, ,, 
 
 Sea-salt gives it 
 Sal-ammoniac ,, 
 
 Alum throws down . 
 
 Salts of tin ,, 
 
 Salts of iron ,, 
 
 Salts of copper ,, 
 
 Bright red. 
 
 A blue. 
 
 A crimson tint. 
 
 A ruby-red tint. 
 
 A brownish-red precipitate. 
 Red precipitates. 
 
 Red -brown precipitates. 
 Cherry-brown precipitates. 
 
 There are no mordants required for dyeing with archil. It is not used 
 for cotton dyeing, but extensively for silk and woollen, imparting very 
 beautiful tints, which, however, are not permanent. It is often used as a 
 bottom colour for reds which are to be dyed by safflower, cochineal, &c., 
 and gives depth and a beautiful rich crimson tint to the colours so dyed. 
 
 Litmus is made from the archil liquor as a sort of pigment, made up 
 with chalk or plaster of Paris into small square cakes. It is not much used 
 in the dye-bouse, but is used as a delicate test for the presence of free acids 
 or alkalies, giving a blue with the latter and a red with the former. 
 
 SOORANJEE. 
 
 This substance was investigated lately by the late Professor Anderson, 
 from whose paper we give the following account, and we give it entire as 
 being interesting from the views given by a chemist not a dyer on certain 
 principles of dyeing: — 
 
 “The subject of these experiments was imported into Glasgow some 
 time since, under the name of Sooranjee, with the intention of introducing 
 it as a substitute for madder in the art of dyeing. For this purpose it was, 
 on its arrival, submitted for trial to some of the most experienced and 
 skilful calico-printers in Glasgow, all of whom concurred in declaring it 
 not to be a dye at all, and to be totally destitute of useful applications. My 
 friend, Professor Balfour, happening to hear of this circumstance, was so 
 good as to obtain for me a quantity of the root, which has enabled me to 
 submit it to a chemical investigation. 
 
 “ Sooranjee is the root of the plant, and is imported cut up into pieces 
 from one to four inches in length, and varying in diameter from half down 
 to nearly an eighth of an inch. On the small pieces the bark is thick, and 
 forms a large proportion of the whole root, but on the larger fragments it 
 is much thinner. Its external colour is pale greyish-brown; but when 
 broken across, it presents colours varying from fine yellow to brownish-red, 
 and confined principally to the bark. The wood itself has only a slight 
 
SOORANJEE. 
 
 309 
 
 yellowish shade, deepest in the centre, and scarcely apparent close to the 
 bark ; but it is coloured dark red by alkalies, indicating the presence of a 
 certain quantity of colouring matter in it. The bark is readily detached, 
 and its inner surface, as well as that of the wood, has a peculiar silvery 
 appearance, most apparent on the large pieces, and almost entirely absent on 
 the smaller. Boiled with water, it gives a wine-yellow decoction, and with 
 alcohol a deep-red tincture. 
 
 “ Solution of morindine gives with subacetate of lead a precipitate 
 depositing itself in crimson flocks, which is extremely unstable, and cannot 
 be washed without losing colouring matter. With solutions of baryta, 
 strontia, and lime, it gives bulky-red precipitates, sparingly soluble in 
 water. Perchloride of iron produces a dark-brown colour, but no pre- 
 cipitate. When its ammoniacal solution is added to that of alum, the 
 alumina precipitated carries down with it the morindine as a reddish-lake ; 
 and when added to perchloride of iron, a brown precipitate is thrown 
 down which cannot be distinguished from pure peroxide of iron, but 
 which contains morindine, as the supernatant fluid is colourless. 
 
 “ The formula thus ascertained brings out an interesting relation 
 between morindine and the colouring matters of madder, and more 
 especially that one which is obtained by the sublimation of madder 
 purple. From his analysis of this substance, Schiel deduces the formula 
 C7H4O4. As this, however, is no more than the simplest expression of the 
 analytical results, and as all the other madder-colouring matters examined 
 contained twenty-eight equivalents of carbon, we are justified in supposing 
 its real constitution to be represented by quadruple of that formula, or 
 C 28 H 16 0 16 , which differs from that of morindine by a single equivalent of 
 water only. The unsublimed madder purple is also connected, though 
 more remotely, with morindine, and differs only by containing five equi- 
 valents of hydrogen less, its formula according to Schiel being C2 sHioOi 5 . 
 
 “ This similarity, however, does not extend itself to their properties 
 as dyes, in which respect they differ in a very remarkable manner. I have 
 already mentioned that the calico-printers had entirely failed in producing 
 a colour by means of sooranjee : and this I have fully confirmed as regards 
 the common mordants. I digested morindine for a long time, in a gradually 
 increasing heat, with small pieces of cloth mordanted with alumina and 
 iron ; but nothing attached itself, and the mordants, after boiling for a 
 minute or two with soap, were found to be unchanged. Even with the 
 root itself alum mordant only acquired a slight reddish-grey shade, and 
 iron became scarcely appreciably darker in colour. The case was different, 
 however, when cloth mordanted for Turkey red was employed. I obtained 
 from Glasgow pieces of calico prepared for Turkey red both by the old 
 and new processes ; and I found that both acquired with morindine, in the 
 course of a couple of hours, or even less, a dark brownish-red colour, 
 devoid of beauty, but perfectly fixed. These observations agree with the 
 account given by Mr. Hunter of the method of dyeing with the M. citri- 
 folia employed by the Hindoos. The cloth is first soaked in an imperfect 
 
310 
 
 SOORANJEE. 
 
 soap, made by mixing the oil of the Sesomum Orientate with soda-ley. After 
 rinsing and drying, it is treated with an infusion of myrobalans (the 
 astringent fruit of the Terminalia chebula), and exposed for four or five 
 days in the sun. It is then steeped in solution of alum, squeezed, and 
 again exposed for four or five days. On the other hand, the powdered 
 roots of the Morinda are well rubbed with oil of sesamum, and mixed with 
 flowers of the Ly thrum fruticosum (Roxburgh), or a corresponding quantity 
 of purwas (the nut-gall of a species of Mimosa'). The whole is introduced 
 along with the cotton into a large quantity of water, and kept over a gentle 
 fire for three hours, when the temperature is brought to the boiling point. 
 The red colour so obtained is, according to Mr. Hunter, more prized for its 
 durability than its beauty. This is simply a rude process of Turkey red 
 dyeing. He also mentions that, by means of iron mordant, a lasting 
 purple or chocolate is obtained ; but in this case the colour is probably 
 affected by the tannin of the astringent matters employed in the process. 
 
 “ Morindine is a true colouring matter, and is capable of attaching 
 itself to common mordants. It gives with alumina a deep rose-red, and 
 with iron violet and black ; but the colours are not very stable, and it has 
 a strong tendency to attach itself to the unmordanted parts of the cloth 
 and to degrade the white. Morindine after treatment with sulphuric acid 
 is capable of attaching itself to ordinary mordants. 
 
 “ The discovery of a peculiar colouring matter capable of fixing itself 
 exclusively on Turkey red mordant, is of interest as establishing the 
 existence of a peculiar class of dyes hitherto totally unsuspected, a class 
 which may be extensive, and may yield important substances. It may 
 serve also in some respects to clear up the rationale of the process of 
 Turkey red dyeing, which has long been a sort of opprobrium of chemistry. 
 Although that process has been practised for a century in Europe, and has 
 undergone a variety of improvements, no clear explanation of it was for a 
 long time given ; but it was supposed that, by the action of the dung, of 
 which large quantities are employed, the cloth underwent a species of 
 animalisation , as it was called, by which it acquired the property of receiv- 
 ing a finer and more brilliant colour than could be attached to it by purely 
 mineral mordants. Recent experiments have, however, shewn that the oil, 
 which is largely employed in the process, undergoes decomposition by 
 long exposure to the air in contact with decomposing animal matter, and 
 is converted into a sort of resinous matter, which constitutes the real 
 mordant for Turkey red. This has been pretty clearly made out by the 
 experiments of Weissgerber. He found that when cloth had been treated 
 with oil, so as to give when dyed a fine rose-red colour, he could, by 
 digestion with acetone, extract from it the altered oil; and as it was 
 removed, the cloth gradually lost the power of attracting the colouring 
 matter of madder, until, when it was entirely separated, the cloth passed 
 through the dye without acquiring any colour. On the other hand, he 
 found that by applying the substance extracted by acetone in sufficient 
 quantity to cloth, he could obtain the richest and deepest colours with 
 
CARAJURU, OR CHICA. 
 
 311 
 
 madder, without the addition of any other substance whatsoever. These 
 observations receive additional confirmation from the experiments detailed 
 in the present paper, as it must be sufficiently obvious that the dark-red 
 colour obtained on Turkey red mordant with morindine must be entirely 
 irrespective of the alumina, on which that substance is incapable of fixing. 
 
 “ I fully agree with the opinion expressed by Persoz, that the use of 
 alum mordant, which is at present always employed in Turkey red dyeing, 
 will be entirely abandoned as soon as calico-printers have learned the 
 method of modifying at will the oil which they employ, so as to bring it at 
 once into the state in which it acts as a mordant. Some steps have been 
 made in this direction by making use of some chemical agents, as nitric 
 acid and chloride of lime, for the purpose of acting on the oil ; but the 
 improvements which have been effected stop far short of what I believe 
 will eventually be effected when the system of pure empiricism, which 
 has been all along employed in this particular process of dyeing, is aban- 
 doned, and the subject submitted to really scientific investigation. It is 
 understood that M. Chevreul has entered upon the inquiry, and in his 
 hands there is little doubt but that it will meet with a satisfactory 
 solution. 1 ’ — From the Transactions of the Royal Society of Edinburgh. 
 
 These hopes of the professor have not been yet realised ; but so far 
 as this colouring matter is concerned, there is a field of inquiry yet open 
 to the practical dyer. Many years ago Bancroft and others dyed with 
 this vegetable ; and it is known that the Hindoos have used sooranjee for 
 centuries for dyeing reds ; it is also used by the Javanese for the same 
 purpose. 
 
 Carajuru, or Chica, 
 
 Is a vegetable substance known by these names, and is obtained from 
 America, where it is used by the natives as a dye. The following short 
 extracts from a paper by J. J. Yirey, will shew its character and pro- 
 perties : — 
 
 “ M. de Humboldt has described in the Annales de Chemie et Physique 
 (vol. xxvii. p. 315), under the name of Chica , a vegetable product of a 
 brick -red colqur, obtained by macerating in water the leaves of Bignonia 
 chica, a shrub of the family of the Bignoniacex , from equinoctial America. 
 
 “As we have obtained from Para in Brazil, under the denomination 
 Crajuru or Carajuru , a substance not only analogous in its physical and 
 chemical characters to the Chica , but of a red-brown violet tint much 
 more beautiful and rich, and like vermilion, whilst the other appeared 
 duller and much inferior, it may be useful to give fresh details about this 
 product, which has been imported to be tried in dyeing. 
 
 “ The Crajuru or Carajuru (Carucuru according to others) is a kind of 
 powder or fecula, in pieces somewhat light, inodorous, insipid or slightly 
 bitter, not soluble in water, but soluble in alcohol, ether, and the oils and 
 
312 
 
 WONGSHY. 
 
 fats, without being completely resinous, burning with a flame, but leaving 
 a quantity of grey cinders. It is wholly dissolved by alkalies, and acids 
 precipitate it without greatly altering its colour, if they are not con- 
 centrated. 
 
 “The Crajuru now brought into Europe must furnish a rather strong 
 and beautiful dye, the brilliancy of which appears quite superior to that of 
 Orleans.” 
 
 According to Boussingault, chica contains a yellowish-orange colour, 
 which has been investigated by Dr. Erdmann, who gives the formula 
 CsH 80 3 as its composition. It is found to dye deep shades upon wool 
 with muriate of tin, and after treating the colouring matter with an acid 
 and washing, it gives a deep-red colour, similar to lac-dye upon cotton 
 mordanted either with tin or alumina. 
 
 WONGSHY 
 
 Is another vegetable substance. An investigation of its properties was 
 made by W. Stein, from whose paper we extract the following account : — 
 
 “ A few years ago a new material for dyeing yellow, called wongshy , 
 was exported on experiment from Batavia to Hamburg, for a sample of 
 which I am indebted to the kindness of M. Yollsack, merchant. Whether 
 it has hitherto been applied as a dyeing material, and with what results, 
 could not be ascertained. The following notice, therefore, will probably 
 not be without interest 
 
 “ The new dyeing material consists of the seed-vessels of a plant, 
 which, according to the information from M. Reichenbach, belongs to the 
 family of the Gentianece. The form of the unilocular capsules is longish- 
 ovate, drawn out to a point next the end of the peduncle, and crowned 
 upon the opposite and more obtuse one with the dried six-lobed calyx. 
 They vary in size, but on an average their length is 1-5 to 2 inches, and the 
 diameter at the thickest part 0-5; the colour is not uniformly reddish- 
 yellow, but at some places darker, at others lighter. The surface is more 
 or less irregularly waved with six to eight longitudinal ribs. The odour 
 resembles saffron, and subsequently honey. The shell is pretty hard and 
 brittle, but becomes quickly mucilaginous when chewed, imparting a yellow 
 colour to the saliva, with a slightly bitter taste ; it swells up considerably 
 in water. Inside the capsules there are a number of dark reddish -yellow 
 seeds (in one specimen I counted 108) ; they are not attached to the sides, 
 but are imbedded in a hardened pulp, and so connected one with the other. 
 These seeds are tolerably hard, soften but slowly when chewed, have no 
 particular taste, but after some time produce at the point of the tongue a 
 slight but peculiar sourish-sweet pungency, resembling the action of Para- 
 guay rue. The pulp, on the other hand, cementing them together, has a 
 
W0NGSI1Y. 
 
 313 
 
 strong bitter taste, which is particularly perceptible at the back part of the 
 palate. 
 
 “ The wongshy, especially when pounded, readily gives up to water, 
 both at the usual temperature as well as on boiling, a colouring principle, 
 which possesses such an enormous divisibility that two parts of the 
 pounded capsules furnish 128 parts of a liquid, which, placed in a cylin- 
 drical vessel of white glass, with a diameter of 3 inches, still appears of a 
 bright wine-yellow colour. The concentrated extract is very mucilaginous, 
 and has a fiery-red colour, which, on large dilution, passes into a golden 
 yellow, the red disappearing. 
 
 “ Protochloride of tin produces no change at the ordinary tempera- 
 ture, or after a long time ; on boiling, a dark orange-coloured precipitate 
 results. 
 
 “ Acetate of lead produces no change. 
 
 “ Basic acetate of lead causes a turbidness at the ordinary tempera- 
 ture, and an orange-coloured precipitate on boiling. 
 
 “ Protosulphate of iron changes the colour into a dark brownish- 
 yellow, without, however, a precipitate resulting either in the cold or on 
 ebullition. 
 
 “ Alum, acetate of alumina, and acetate of zinc produce yellow 
 precipitates only on boiling. 
 
 “ Barytic- water causes a yellow precipitate at the ordinary tempera- 
 ture, which, on boiling, acquires a reddish tint. 
 
 “ Lime-water gives a pure yellow precipitate ; solutions of gypsum and 
 chloride of calcium are not precipitated by it even on boiling ; well-water, 
 with a considerable amount of carbonate of lime, does not precipitate the 
 colouring principle even with the assistance of heat : it is consequently not 
 able to decompose the combinations of lime with acids. 
 
 “ To ascertain the value of the wongshy colouring matter for the pur- 
 poses of dyeing, one part of the pounded capsules was digested for twelve 
 hours with twenty parts of lukewarm water, being frequently stirred, and 
 the liquid then strained. The colouring matter is most quickly extracted 
 in this manner without its becoming gelatinous from the formation of paste, 
 as would happen were the liquid boiled. Properly prepared samples of 
 woollen cloth (some without any mordant, others mordanted with alum, 
 protochloride of tin, acetate of alumina, and basic acetate of lead) were 
 dyed with this extract at a temperature of about 104° Fah. ; the colour 
 does not turn out so pure at a higher temperature. The unmordanted 
 cloth was dyed a beautiful and uniform orange colour by one immersion ; 
 of the mordanted samples, those with alum and acetate of alumina were 
 better than those with protochloride of tin; the least satisfactory was that 
 in which basic acetate of lead had been used as mordant. The tone of the 
 colour was not altered by the three first mordants, but it was less intense, 
 and the stuffs were not uniformly penetrated by the colouring matter. 
 However, the samples with alum mordant gave perfectly satisfactory 
 results after a second immersion. The colouring matter likewise combines 
 
311 
 
 WONGSHY. 
 
 readily and uniformly with silk, communicating to it a very glowing golden 
 colour, so that in this case I also prefer not having recourse to mordants. 
 Cotton, as was to be expected, can only be dyed with the assistance of 
 mordants, and the best results appeared to be obtained with tin mordants ; 
 the colour was orange, of a very agreeable tint. 
 
 “ The colour, both upon wool, silk, and cotton, resists soap per- 
 fectly; but alkalies give it a yellow, acids and tin salts a red tint. By this 
 behaviour it differs from the colour of annotta, with which, as will 
 subsequently be seen, it possesses in other respects great resemblance — 
 a resemblance which unfortunately exists as regards the action of light. 
 When exposed to light, the colour very soon fades upon cotton, less 
 quickly upon wool ; and in this case it is more permanent upon the unmor- 
 danted samples. It resists the light longest upon silk, and in this respect, 
 when compared with the other known yellow colours, may be reckoned 
 among the best. 
 
 “ I obtained a beautiful yellow, with a faint tint of red, by mordant- 
 ing the woollen cloth with lime-water and immersion in the boiling vat ; 
 it resists the soap perfectly, and the action of light much better than the 
 orange. It is altered in a similar manner to the orange by alkalies, acids, 
 and tin salts, only less. Several very beautiful shades of yellow may be 
 obtained by adding pearlash or caustic potash to the dye, and immersing 
 the unmordanted fabric at the ordinary temperature. The union of the 
 colour with the fibre takes place very quickly and very uniformly. By the 
 addition of one part pearlash to thirty parts dye liquor, a yellow was 
 obtained with a remarkable glow from a slight admixture of red. By the 
 addition of twice the quantity of pearlash, a lively yellow, with a faint 
 tint of green, was obtained. A still larger amount of pearlash cannot be 
 used, as it renders the colour dull and impure. With caustic potash 
 instead of pearlash, I obtained, in the first place, a pure brilliant yellow, 
 with less red than with the pearlash ; in the latter case, a beautiful canarv- 
 yellow, with a shade of green. Ammonia acts in the same manner ; but 
 the colour, under all circumstances, contains more red. The colour also 
 appears of a somewhat different shade when the fabrics are first immersed 
 in the dye liquor, and then, after being washed, placed in an alkaline bath. 
 
 “ In the case of silk and cotton the effect of alkalies is similar, but 
 less apparent, because the silk and cotton fibres imbibe less of the colour- 
 ing substance than those of wool. 
 
 “ That this colour resists the soap is self-evident, but it also suffers 
 less from the action of light than the orange; and when fabrics so dyed 
 are passed through a vinegar or muriatic acid bath a brilliant aurora colour 
 is obtained. This interesting behaviour, which the jvongshy colouring 
 matter has in common with that of annotta, is explained by the chemical 
 character of the former, which is a weak acid; it combines with the 
 alkalies and with the alkaline earths, as evident by the precipitation with 
 baryta and lime-water. Its combinations with the former possess a pure 
 yellow colour, and are decomposed by stronger acids, when the liberated 
 
ALOES. 
 
 315 
 
 colouring matter separates of a brilliant vermilion colour. But the colour- 
 ing matter thus separated is no longer the same as that which was origin- 
 ally contained in the aqueous solution, for it is now perfectly insoluble in 
 water, and is only dissolved in small quantity, and of a golden-yellow 
 colour, by absolute alcohol, ether, and spirit of 0-863 specific gravity. 
 In the moist state it has a vermilion colour ; when dry and in the 
 purest state it is brown-red, like Ratanhia extract, and is easily reduced 
 to powder; but if it still contains sugar and fat, it has a beautiful 
 yellowish-red colour in thick layers, whilst in thin layers it is yellow 
 and transparent, and becomes moist in the air. On heating the pure 
 substance upon platinum, at first yellow vapour is given off, and at 
 some spots the colour becomes pure yellow ; it subsequently turns black, 
 fuses, and chars. The residual cinder is difficult to burn ; the yellow 
 vapours condense, when the experiment is made in a glass tube, into yellow 
 oily drops. Concentrated sulphuric acid renders it scarcely perceptibly 
 blue, and the acid acquires the same colour, which quickly passes into 
 violet and brownish-red, whilst the colouring matter slowly dissolves. 
 Water separates from this solution a dirty yellowish -grey flocculent 
 substance. 
 
 “The reaction of the wongshy colouring matter which has just been 
 mentioned has no resemblance with the reaction of sulphuric acid upon 
 annatto, for the liquid never acquires a pure blue colour, as is the case 
 with annotta, but is violet from the first, and only for a minute. 
 
 “It dissolves readily in caustic ammonia and caustic soda, with a 
 golden-yellow colour.” 
 
 Wongshy is used in China for dyeing yellow, and also for green, along 
 with indigo. It is also used for giving a bottom to silk or cotton to be 
 dyed cherry or scarlet with safflower, in the same way as annotta is used in 
 this country; but as a dye alone it does not possess that permanence 
 required and obtained by other colouring matters, and hence it has not 
 been much used in this country. 
 
 Aloes. 
 
 Dr. Bancroft, in his work on the Philosophy of Permanent Colours , 
 recommended this substance as a dyeing agent. Pie proposed to digest it 
 in nitric acid, by which means he obtained aloetic acid, a substance capable 
 of being used as a dye. This matter has been the subject of extensive 
 investigation by many chemists, and has been occasionally more or less used 
 as a dyeing agent. 
 
 The aloes contain a yellow crystalline matter, soluble in cold water, 
 called aloin , and a resinous-looking substance, soluble in boiling water, 
 called aloetin. The first substance, when the solution is evaporated, yields 
 crystals which, according to Dr. Stenhouse, have the formula Ci7pli 8 0 7 . 
 Commercial aloes yield in 100 parts — 
 
316 
 
 Aloin, . 
 Aloetin, . 
 Albumen, 
 
 PITTACAL. 
 
 69-2 
 
 25-6 
 
 5-2 
 
 100-0 
 
 When aloes are treated with nitric acid they yield several coloured com- 
 pounds, some of which have been used in dyeing wool and silk brown, 
 violet, and other colours, according to the mordants employed, which are 
 permanent. Cotton is also dyed with tin mordants. The mode of pre- 
 paring the aloes for dyeing formed the subject of a patent in this country. 
 The following was the proposed method of preparation : — 
 
 “The mode of preparing the colouring matter from aloes is as follows : — 
 Into a boiler or vessel capable of holding about 100 gallons, the patentee 
 puts 10 gallons of water and 132 lbs. of aloes, and heats the*same until the 
 aloes are dissolved; he then adds 80 lbs. of nitric or nitrous acid, in small 
 portions at a time, to prevent the disengagement of such a quantity of 
 nitrous gas as would throw part of the contents out of the boiler. When 
 the whole of the acid has been introduced, and the disengagement of gas 
 has ceased, 10 lbs. of liquid caustic soda, or potash of commerce, of about 30° 
 are added, to neutralise any undecomposed acid remaining in the mixture, 
 and to facilitate the use of the mixture in dyeing and printing. If the 
 colouring matter is required to be in a dry state, the mixture may be incor- 
 porated with 100 lbs. of China clay, and dried in stoves, or by means of a 
 current of air. In preparing the colouring matter from extract of logwood, 
 the materials are used in the manner and proportions above described ; the 
 only difference being that the extract of logwood is substituted for the 
 aloes. 
 
 “The colouring matter is used in dyeing by dissolving a sufficient 
 quantity in water according to the shade required, and adding as much 
 hydrochloric acid or tartar of commerce as will neutralise the alkali con- 
 tained in the mixture, and leave the dye-bath slightly acidulated. The 
 article to be dyed is introduced into the bath, which is kept boiling until 
 the desired shade is obtained. 
 
 “ When the colouring matter is to be used in printing, a sufficient 
 quantity is to be dissolved in water, according fco the shade required to be 
 produced; this solution is to be thickened with gum, or other common 
 thickening agent; and hydrochloric acid, or tartar of commerce, or any 
 other suitable supersalt is to be added thereto, for the purpose before men- 
 tioned. After the fabrics have been printed with the colouring matter, they 
 should be subjected to the ordinary process of steaming to fix the colour.” 
 
 PlTTACAL. 
 
 This substance is obtained from beech tar. It is dry and hard, very 
 brittle, and resembles indigo in appearance. It has no taste or smell, and 
 
BARBARY ROOT. 
 
 317 
 
 does not dissolve in water. Sulphuric acid dissolves it, producing a violet- 
 coloured solution. Muriatic acid gives a red-purple solution, from which 
 alkalies precipitate the pittacal. Acetate of lead, salts of tin, sulphate of 
 copper, acetate of alumina, all give deep-blue precipitates, not readily- 
 changed. This colour is fixed easily upon cotton by tin and alumina. 
 Although this substance has been long known, it has never been much 
 used as a dye. 
 
 Barbary Boot. 
 
 The plant from which this is obtained grows in almost every part of 
 the world; great quantities of it are obtained from India, where it grows in 
 great abundance and perfection. The colouring matter is found in the 
 whole of the root. In the stem it is found round the pith and near the 
 bark. This colouring substance is much used in dyeing or staining leather, 
 but it is not much used in dyeing of cotton. It contains a large quantity 
 of astringent matter, and is therefore very useful in preparation of leather, 
 and may be used for woollen and cotton in dyeing blacks. Mr. Edward 
 Solly has made some investigations of this root. — See Journal of the Royal 
 Asiatic Society. 
 
 Were we to enumerate the various vegetable substances that have been 
 used in dyeing, and may still be used by some, the list would extend to 
 almost all our vegetable products. Before the introduction of Brazil- 
 wood, logwood, sumach, and bark, the natives of this country, and many 
 in the Highland districts still continued to use the woods and shrubs 
 that grew around them. The following are a few that were well known 
 to every housewife: — Bark of the alder and the willow, both flower and 
 seeds of the broom and the whin, the horse chestnut and the holly. 
 These, and several others, gave colours of various tints, but they were 
 generally used along with copperas and alum, and a free use of laut 
 (urine), which no doubt, in many ca,ses, produced fermentation and oxi- 
 dation. Time was no object — the woollen was alternately boiled, and 
 steeped, and exposed to the air for days, until the desired depth was 
 obtained. The colours thus produced wanted brightness, but were gene- 
 rally permanent. Becently a class of colours, or rather tints, have been 
 in fashion which requires a nomenclature of their own. They are neither 
 red, blue, nor yellow; brown, violet, nor green; drab, slate, nor grey; and 
 yet they partake of all these. To produce such tints with the ordinary 
 dyeing agents in use a few years ago would certainly have puzzled 
 the most experienced dyer; but the chemist has come to the aid of the 
 dyer in a way which, if the dyer do not learn chemistry, he will be 
 reduced to the condition of a mere labourer. This will be more noticed 
 in speaking of the coal-tar colours. The most ordinary vegetable and 
 animal substances are being converted into dyes: sawdust of all sorts, 
 lichens, mosses, bran, paper and cotton waste, blood, horns, resins, 
 
318 
 
 COCHINEAL. 
 
 gum, &c. These are heated under pressure to from 300° to 400° Fah., 
 with water and caustic soda. A decomposition takes place, — sulphide of 
 sodium is produced, which acts upon the organic matter, liberating sul- 
 phide of hydrogen, and there is left a mass soluble in water, giving a 
 greenish-coloured solution, which is said to dye cotton and woollen a variety 
 of tints, according to the strength of solution used, and without a mordant; 
 although by the use of bichromate of potash as a mordant, and other 
 oxidising bodies, the tints are varied, and with other colouring matters 
 any mixed shade may be obtained, having a peculiar beauty of its own. 
 These reactions may only be the beginning of a new set of chemical com- 
 pounds that will yet open up a field of inquiry and application to the 
 practical dyer. 
 
 Cochineal. 
 
 This is a small insect, called the- Coccus cacti , and is much sought after 
 for its tinctorial qualities. It furnishes the finest known shades of crimson, 
 red, purple, scarlet, &c., for woollen and silk. The insects are reared in 
 great abundance in Mexico. They feed upon a cactus plant which the 
 natives cultivate round their dwellings for that purpose. The insects attach 
 themselves to the leaves of the plant, and increase rapidly in number. The 
 females live about two months, and the males only about one month. The 
 season of rearing and gathering lasts about seven months : during this 
 period the insects are gathered three times. After each gathering some of 
 the branches and leaves containing females and their young are preserved 
 under shelter, and on the return of the proper season they are distributed 
 over the plantation. A few females are put into a small nest made of some 
 downy substance, and the young insects quickly spread themselves out upon 
 the leaves, to which they attach themselves. They are gathered by brushing 
 them off the leaves with the feather end of a quill into boiling hot water, in 
 which they are kept a few seconds. This not only kills them instantly, but 
 causes them to swell to twice their natural size. When taken out of the hot 
 water they are spread out and dried, and then packed for the market. 
 Some cultivators instead of hot water use steam, and others again place 
 them in an oven or upon a hot plate. The differences in the appearance 
 of cochineal are caused by these different modes of killing the insects 
 and heating them. They shrivel in drying, and assume the appearance of 
 irregular formed grains, fluted and concave. The best sort seem as if 
 dusted with a white powder, and are of a slate-grey colour ; but this 
 appearance is often imparted by means of powdered talc, to deceive the 
 purchaser. 
 
 There are three kinds of cochineal in commerce. The finest is known 
 by the name of mistic , from the name of the place in which the insects are 
 reared, La Mistica, in the province of Honduras. Another is called wild, 
 because they are collected from plants growing in a state* of nature ; but 
 this variety is inferior to the former. The third is a mixture of these two, 
 
CARMINE. 
 
 319 
 
 or rather the debris or fragments, and varies in quality according to the 
 proportion of the mixture. 
 
 Cochineal has been the subject of several chemical investigations, the 
 results of which are not very satisfactory. The following are instances of 
 these. The cochineal contains — 
 
 1. Carmine, which may be termed tfc 
 
 2. A peculiar animal matter. 
 
 3. A fatty matter, composed of . 
 
 4. Saline matters, as .. 
 
 Mr. John gives the following as 
 
 .e colouring matter. 
 
 ( Stearine, 
 
 Bleine, and 
 ( Volatile fatty acids, 
 f Phosphate of lime. 
 
 Carbonate of lime. 
 
 Chloride potassium, 
 j Phosphate of potash. 
 
 I Combination of potash with organic 
 l acids. 
 
 the result of his analysis : — 
 
 Red colouring matter, 50 ’0 
 
 Gelatine, 10-5 
 
 Wax, . 10-0 
 
 Debris of skin, &c., ........... 14-0 
 
 Gummy matter, . . . . . . . . . 134) 
 
 Phosphate of lime, of potash, and iron, and chloride potassium, 14-0 
 
 Carmine, or the colouring matter of cochineal, may be obtained by 
 macerating finely ground cochineal with ether, which dissolves out the 
 fatty matter, and then dissolving the carmine by the application of hot 
 alcohol, and leaving the solution to cool : on evaporating the alcohol, the 
 carmine is deposited as a beautiful red crystalline substance, which dissolves 
 freely in water. It is affected by the following re-agents, as under: — 
 
 Tannin .... 
 Most acids . 
 
 Boracic acid . 
 
 Potash, soda, and ammonia 
 Baryta and strontia 
 Lime .... 
 Alumina 
 
 Gives no precipitate. 
 
 Change its colour from a bright to a 
 yellowisli-red. 
 
 Does not change the colour, but rather 
 reddens it more. 
 
 Change it to a crimson- violet. 
 
 Produce the same effect. 
 
 Gives a crims on- violet precipitate. 
 
 Combines with it and precipitates it as a 
 beautiful red ; but if boiled it passes to 
 violet-red. 
 
 A little potash, soda, or ammonia added 
 prevents this change, and preserves the 
 stability of the red. 
 
320 
 
 COCHINEAL. 
 
 Protoxides of tin . 
 Peroxide of tin 
 Salts of iron . 
 
 Change it to crimson-violet. 
 Changes it to yellowish-red. 
 
 Turn it brown ; no precipitate. 
 Change it to violet ; no precipitate. 
 Change it to violet ; no precipitate. 
 Gives a scarlet-red precipitate. 
 
 Has no action upon it. 
 
 Turns it yellow. 
 
 Salts of lead . 
 
 Salts of copper 
 Nitrate of mercury 
 Nitrate of silver . 
 Chlorine 
 
 “ As may be supposed, it is next to impossible to judge of the 
 goodness of a cochineal by its physical characters. In order to ascertain 
 its value, we must have recourse to comparative experiments. We are 
 indebted to MM. Robiquet and Anthon for two methods of determining 
 the quality of cochineals according to the quantity of carmine they 
 contain. The process of M. Robiquet consists in decolourising equal 
 volumes of decoction of different cochineals by chlorine. By using a 
 graduated tube, the quality of the cochineal is judged of by the quantity 
 of chlorine employed for decolourising the decoction. The process of 
 M. Anthon is founded on the property which the hydrate of alumina 
 possesses of precipitating the carmine from the decoction so as to de- 
 colourise it entirely. The first process, which is very good in the hands 
 of a skilful chemist, does not appear to us to be a convenient 
 method for the consumer : in the first place, it is difficult to procure 
 perfectly identical solutions ; in the next place, it is impossible to keep 
 them a long time without alteration. We know that chlorine dissolved in 
 water reacts, even in diffused light, on this liquid, decomposes it, appro- 
 priates its elements, and gives rise to some compounds which possess an 
 action quite different from that of the chlorine solution in its primitive 
 state. The second process seems to us to be preferable, as the proof 
 liquor may be kept a long while without alteration. A graduated tube is 
 also used ; each division represents one-hundredth of the colouring matter. 
 Thus, the quantity of proof liquor added exactly represents the quantity in 
 hundredths of colouring matter contained in the decoction of cochineal 
 which has been submitted to examination. 
 
 “ The colouring matter of cochineal being soluble in water, I have 
 used this solvent for exhausting the different kinds which I have submitted 
 to examination in the colorimeter. I operated in the following manner : — 
 I took a grain of each of the cochineals to be tried, dried at 122° Fah. ; I 
 submitted them five consecutive times to the action of 200 grains of dis- 
 tilled water at water-bath, heat, each time for an hour ; for every 200 
 grains of distilled water I added two drops of a concentrated solution of 
 acid sulphate of alumina and of potash. This addition is necessary to 
 obtain the decoctions of the different cochineals exactly of the same tint, 
 in order to be able to compare the intensity of the tints in the colori- 
 meter. Care must be taken not to add to the water, which serves to 
 extract the colouring matter from the different cochineals, more than the 
 
COCHINEAL. 
 
 321 
 
 requisite quantity of acid sulphate of alumina and solution of potash, 
 because a stronger dose would precipitate a part of the colouring matter in 
 the state of lake. 
 
 “ In order to estimate a cochineal in the colorimeter, two solutions, 
 obtained as described above, are taken ; some of these solutions are 
 introduced into the colorimeter tubes as far as zero of the scale, which is 
 equivalent to 100 parts of the superior scale ; these tubes are placed in the 
 box, and the tint of the liquids enclosed is compared by looking at the two 
 tubes through the eye-hole, the box being placed so that the light falls 
 exactly on the extremity where the tubes are. If a difference of tint is 
 observed between the two liquors, water is added to the darkest (which is 
 always that of the cochineal taken as type) until the tubes appear of the 
 same tint. For diluting the liquors the same water must always be used 
 which has served to extract the colouring matter of the cochineals under 
 examination, otherwise the darkest decoction would pass into violet as 
 water was added to it to bring back the tint to the same degree of intensity 
 as that of the decoction to which it is compared. The number of parts of 
 liquor which are contained in the tube to which water has been added is 
 then read off ; this number, compared with the volume of the liquor con- 
 tained in the other tube, a volume which has not been changed, and is 
 equal to 100, indicates the relation between the colouring power and the 
 relative quality of the two cochineals. And if, for example, 60 parts of 
 water must be added to the liquor of good cochineal to bring it to the 
 same tint as the other, the relation of volume of the liquids contained in the 
 tubes will be in this case as 160 is to 100, and the relative quality of the 
 cochineals will be represented by the same relation, since the quality of the 
 samples tried is in proportion to their colouring power.” 
 
 Dr. De la Rue has separated the colouring matter from cochineal, 
 which he finds composed of C 14 H 14 0 8 , and has named it carminic acid. 
 
 Some of the German chemists, supposing that the plant upon which 
 the insect feeds might be the source of the colouring matter, instituted a 
 series of experiments to determine that point, but without success. The 
 conclusion they came to was, that the animal economy plays a prominent 
 part in the formation of the colouring matter. 
 
 Carmine is manufactured extensively in France, and is used for 
 superior red inks, paints, and for colouring artificial flowers. It is pre- 
 pared on the large scale by boiling a quantity of cochineal in water with 
 soda, and then adding to it a little alum, cream of tartar, and the white of 
 eggs, or isinglass, which separates the carmine as a fine flaky precipitate. 
 This precipitate is carefully collected. 
 
 There is something in the production of good carmine which is not 
 yet fully understood. It has not yet been prepared in this country in the 
 same perfection as in France (page 13). It is found also that with a 
 coal fire to boil the solution, a smaller quantity of it is produced than 
 when a wood fire is employed, and there are many other little points 
 which shew the delicacy of its preparation. 
 
 x 
 
322 
 
 LAKE LAKE, OR LAC. 
 
 The residue of the carmine, and some portions of the precipitate from 
 the cochineal, when first taken from the boiler, are collected and boiled in 
 water; to this mixture is added a solution of alum and chloride of tin, by 
 which a beautiful red-coloured precipitate or lake is formed. This con- 
 stitutes the beautiful pigment known as carmine lake. 
 
 Lake Lake, or Lac, 
 
 Is a concrete juice which distils from several kinds of plants. It 
 appears, however, to be determined that it is caused by an insect named 
 Coccus ficus, or Csecus loco , and may therefore be regarded as of animal 
 origin. There are several varieties of this product under the names of 
 stick lac , seed lac , and shell lac. There are also brought from India two 
 other products distinguished as lac lac and lac dye , which are the kinds 
 mostly used in dyeing, but their composition is not very well known. 
 They, however, contain a goodly quantity of resinous matter, which must 
 be destroyed before they are used as dyes. Lac lac is obtained fit for 
 use as a dye by boiling the gum lac with alkaline water, which dissolves 
 the colouring matter along with some of the resinous. To this is added some 
 alum, which precipitates the whole as an aluminous product, in which state 
 it is used. 
 
 Dr. Bancroft discovered that acids destroyed the resinous matter of lac 
 dye, and rendered the colouring matter soluble, and this is now the mode 
 generally adopted in working with this substance. 
 
 The following may be taken as the ordinary means of producing this 
 colour: — Add to four pounds of lac dye three pounds of strong sulphuric 
 acid, and set the mixture aside for two days; pour over it half a gallon of 
 boiling water, stir the whole well, and leave it to settle for twenty-four 
 hours ; the clear liquor is then to be decanted into a leaden vessel, and the 
 residue washed with water until all the colouring matter is dissolved. The 
 washings- may be added to the liquor in the leaden vessel. There is then 
 added to this liquor a quantity of lime-water, until the solution barely 
 tastes acid, which forms a precipitate with the sulphuric acid; the whole is 
 then thrown upon a filter, and the clear liquor passing through the filter 
 forms the dye. 
 
 Some dyers take about thirty-two parts of lac fiye, and rub it down 
 fine in ten parts of strong sulphuric acid; then add three times the 
 quantity of the mixture of water, and set aside for two days; it is then 
 ready for use, requiring merely to be diluted as required. 
 
 The French dyers generally take thirty-two parts of lac dye, rubbed 
 down in twelve parts of hydrochloric acid of 30 c Twad.; when well mixed, 
 it is diluted with about an equal quantity of water, set aside for twenty- 
 four hours, and stirred from time to time ; it is then ready for use. Many 
 dyers treat the lac lac in the same way as the lac dye, using one pound of 
 
ULTRAMARINE. 
 
 323 
 
 sulphuric acid to two pounds of lac lac ; in other respects the process is 
 the same. A superior lac dye has recently been prepared by treating stick 
 lac with weak ammonia, and adding tin salt, which precipitates a fine red, 
 which is collected and sold to the dyer. 
 
 The mordants employed for dyeing with the lacs are termed lac spirits; 
 the lac and spirits are mixed previous to using. Lacs are employed as 
 substitutes for cochineal, and most of the colours obtained by the one are 
 producible by the other; but for fine reds the lac is much inferior. This 
 dye is only used for silk and woollen. 
 
 Kerms. 
 
 This is also an animal substance — the dried bodies of another species 
 of the coccus insect. This insect is supposed to have been known as a dyeing 
 agent as early as the time of Moses; it was used in India at a very early 
 age, and was highly valued both by the Romans and Spaniards for dyeing 
 purples ; but after the cochineal dye was discovered, cochineal was used in 
 preference, on account of the superior beauty of the colours. Accordingly, 
 in many countries where the kerms insect was reared and enriched the 
 people, the remembrance of it is lost. 
 
 Good kerms is of a full deep-red colour, having a pleasant smell, and 
 sharp sour taste; the red colouring matter is soluble in water and in 
 alcohol. It possesses properties similar to cochineal. 
 
 Acids render it 
 
 Alkalies, ....... 
 
 Iron salts turn it . 
 
 Alum renders it 
 
 Salts of tin, 
 
 A mixture of iron salts and tartar turns it to . 
 Sulphate of copper and tartar, 
 
 Tin salts and tartar, 
 
 Yellowish-brown. 
 
 Crimson-violet. 
 
 Black. 
 
 Blood-red. 
 
 A bright red. 
 
 Grey colour. 
 Glive-green. 
 Cinnamon-brown. 
 
 A red with tin requires about twelve times the quantity of kerms as 
 of cochineal, and the colour is a little inferior. As a dye, it is not much 
 used, and only for silk or woollen. There is no affinity between cotton 
 and the colouring matters of cochineal , lacs , and kerms.. 
 
 Ultramarine. 
 
 This pigment cannot be considered a dye drug; but as it is used 
 by calico-printers for giving to cloth a beautiful blue and green, 
 we briefly describe its history and manufacture. Lapis lazuli , or 
 ultramarine, is a mineral or precious stone having a blue colour of 
 
I 
 
 324 ULTRAMARINE. 
 
 great beauty, and when finely ground is used by artists as one of 
 their colours. Early in the present century, a French manufacturer 
 of soda discovered a blue substance in one of his furnaces resem- 
 bling this precious stone, which he sent for analysis to M. Vanquelin, 
 an eminent French chemist, who found it to be composed of silica, 
 alumina, soda, and sulphur, in the same proportions, or nearly so, as 
 found in the natural Lapis lazuli , and suggested the probability of its being 
 made an object of manufacture. This induced the Society for the 
 Encouragement of National Industry of France, to offer a prize of £240 to 
 any one who would find out a practical method for making ultramarine at 
 a cost, and in such quantities, as would bring it within the reach of the 
 manufacturer. This was shortly followed by several claimants for the prize, 
 and which resulted in the establishment of several manufactories for the 
 production of the colour by slightly different methods, and also of different 
 tints ; indeed, so progressive has been the manufacture that upwards of 
 thirty different varieties of ultramarine are known in the market, varying 
 in hue from a perfect blue to a beautiful green. The process of manu- 
 facture may be briefly stated, thus : — 100 parts of fine China clay, well 
 washed and dried ; 41 parts of sulphide of sodium, 41 parts of calcined 
 caustic soda, 18 parts of charcoal, and 13 parts of sulphur, are all intimately 
 mixed, and pressed into a fire-clay crucible, which is put into a furnace and 
 kept at a bright red heat for eight hours ; then the heat is raised to whiteness 
 for about an hour ; the crucible is withdrawn, and the whole allowed to 
 cool; the product is ground and washed in water; if the air has been pretty 
 well excluded from the crucible, the colouring matter is green, and will 
 remain insoluble. This green being collected and dried, and with the 
 addition of a little sulphur it is calcined at a red heat, in a free current of 
 air, when it becomes blue. However, there are other methods of preparing 
 the colour, varying slightly in the proportions and manner of manipula- 
 tion, all yielding the same products ; but whichever method is 
 adopted it requires a great deal of care and experience in the management 
 to produce good results. There is a great tendency to dull shades; 
 whereas they should all have* a high pure lustre. These colours are 
 generally printed on cloth with albuminous substances, and are fixed by a 
 steam heat which renders the albumen insoluble. 
 
COAL-TAR COLOURS. 
 
 The organic colouring matters we have hitherto been describing — i.e ., 
 those which are extracted from vegetable bodies, such as logwood, fustic, 
 bark, safflower, &c. — have their existence in the plant, either in the form of 
 a white base, which becomes coloured by the absorption of oxygen from 
 the air, as is the case with indigo, or the colour exists ready formed in 
 the plant, as in safflower, and is extracted by solution in water or an 
 alkaline ley, from which solution it is transferred to the fabric of the cloth. 
 Such organic colours we may term simple educts — the base or colouring 
 matter exists formed in the plant, and only requires some simple method, 
 such as solution, to extract or educe it. It is very different with the 
 organic colours of the coal series. They, on the other hand, may be 
 termed products. The coal containing all the elements necessary for 
 their formation is split up or decomposed by what is called destructive 
 distillation, and its elements recombining in different proportions, give 
 rise to very numerous new products, from some of which the bases of the 
 coal-tar colours are derived. 
 
 It is, no doubt, very puzzling to the uninitiated to comprehend how 
 such beautiful colours can come from such an unlikely substance as coal 
 tar, and we have riot unfrequently heard the remark, “ Who could have 
 imagined that such colours existed in coal tar?” and when told that the 
 colours did not actually exist in it, they have replied, “ How can any one take 
 out of tar that which really does not exist in it ? ” In order to make the 
 matter as clear as possible, we will endeavour to give the reader a brief 
 account of the preliminary processes, and afterwards go on to describe 
 how the colours are formed. For our present purpose we may consider 
 coal to consist of the four elements, carbon, hydrogen, oxygen, and nitro- 
 gen, leaving out for the present the ash or earthy matters it contains. 
 Of the elements named carbon and hydrogen predominate, oxygen and 
 nitrogen only occur in small quantities. In the process of gasmaking the 
 coal is subjected to a high heat in an iron or earthen retort, and the 
 excessive temperature splits up its elements, throws them violently asunder, 
 and they rearrange themselves according to their new affinities, under these 
 new conditions, to form a variety of compounds all vastly different from 
 coal. The bulk of the carbon and hydrogen unite to form a permanent 
 gas, which does not condense on cooling ; hydrogen and oxygen unite to 
 form water, hydrogen and nitrogen to form ammonia, and some of all 
 four elements pass off in the form of vapours, which, on being cooled, 
 condense into a black oily liquid with a disagreeable smell, called coal 
 or gas tar. The reader will perceive that no amount of powdering or 
 
326 
 
 COAL-TAR COLOURS. 
 
 pressing of the coal, no treatment with any solvent could have extracted 
 this gas, ammonia, tar, &c., from it: although the elements for these pro- 
 ductions were all there, it required the destructive distillation to bring 
 about this change. It is, however, with the coal tar alone we have to 
 deal, as all the substances from which the colours are derived are pro- 
 duced from it. 
 
 The tar has the appearance of a black homogeneous-looking liquor ; 
 but when it is put into a still and made to boil, it is found not to have a 
 steady boiling point, like water; a light oil passes over at a comparatively 
 low temperature, and as the heat is raised, the condensed oil passing over 
 continues to increase in specific gravity until, if carried far enough, the 
 distillate thickens and solidifies. In ordinary practice the tar is put into 
 a cast-iron still and heat applied. There first passes over some ammoniacal 
 compounds, and a light oily-looking liquid, called coal-naphtha; this is 
 set apart, and there follows at a higher temperature a heavier oil, called 
 dead-oil ; the residue is then tapped or run from the still and used for 
 pitch, asphalt, or black varnish. 
 
 The first of these products, coal-naphtha, is again distilled ; and as it 
 has been found to consist of a great variety of compounds, each having a 
 different boiling point and distinct properties, these are separated from 
 each other by repeated distillations, always setting apart the portions 
 distilling over within given limits of temperature : this is known as 
 fractional distillation, and the following are a few out of the vast number 
 of definite chemical compounds which have been separated in this way: — 
 
 
 Formula, 
 
 Roiling point. 
 
 Benzol, .... 
 
 c 6 H 6 , 
 
 177° Fah. 
 
 Parabenzol, .... 
 
 c 6 h 6 , 
 
 203° „ 
 
 Toluol, 
 
 c 7 h 8 , 
 
 230° „ 
 
 Xylol, 
 
 c 8 h 10 , 
 
 282° „ 
 
 Cumol, . 
 
 c 9 h 12 , 
 
 300° „ 
 
 Cymol, . 
 
 c 10 h 14 , 
 
 338° „ 
 
 From the heavier portions 
 
 of the coal-tar many 
 
 other important 
 
 hydro-carbons may be obtained, 
 
 such as naphthalene, 
 
 paranaphthalene, 
 
 chrysen, &c., having other formulas. 
 
 Naphthalene, ...... c I0 h 8 . 
 
 Paranaphthalene, C 7 4 *H 10 . 
 
 Chrysen, Ce’EU. 
 
 Again, there are formed a series of compounds having oxygen as part of 
 their composition, along with carbon and hydrogen — of which acetic and 
 carbolic acids are examples, and a series having nitrogen along with the 
 carbon and hydrogen, in which occurs aniline, C 6 H 7 N. 
 
 So far back as 1825, the late Professor Faraday, when experimenting 
 on the composition of gases, found when working with an oil gas a clear 
 
COAL-TAR COLOURS. 
 
 327 
 
 colourless liquid, having an agreeable smell, which he called “ bicarburet 
 of hydrogen.” A substance having similar properties was discovered by 
 Mitscherlich, when distilling benzoic acid, which he called “ benzine.” Dr. 
 llofmann afterwards, about 1845, discovered the same substance in the 
 products of coal tar, and named it benzol, giving as its formula C 6 H 6 . 
 
 In 1826, Unverdorben discovered a substance amongst the products 
 of the distillation of indigo which he called “ crystalline.” Runge obtained 
 the same substance from the distillation of coal, and found it gave a blue 
 colour with chloride of lime ; he therefore called it “ kyanol.” 
 
 Fritzsche still later, again, obtained it from indigo by a different 
 process from Unverdorben, and gave it the name of aniline. Then Zinin 
 obtained it from a substance called nitrobenzol or nitrobenzine, which had 
 been discovered by Mitscherlich in 1834, and Zinin called his substance 
 “ benzedam.” Some time afterwards Dr. Hofmann, when investigating this 
 subject, pointed out that all these bodies — “ crystalline, kyanol, aniline, and 
 benzedam” — were identical in composition. The name aniline was retained, 
 and the others discarded. The next important event in the history of these 
 dyes was the discovery of the mauve dye by Mr. Perkin, who prepared it 
 from aniline, and thus completed the chain of discovery which has led to 
 the opening up of a large field of manufacturing industry.. Benzol could 
 be had. in large quantity from coal tar; by the action of nitric acid on 
 benzol, nitrobenzol could be obtained; from nitrobenzol, aniline; and from 
 aniline the mauve dye.. Mr. Perkin thus briefly describes his discovery of 
 this dye in a lecture read before the Society of Arts : — “ I was endeavouring 
 to convert an artificial base into the natural alkaloid quinine, but my 
 experiments, instead of yielding the colourless quinine, gave a reddish 
 powder. With the desire of understanding this peculiar result, a different 
 base of more simple construction was selected — namely, aniline, and in 
 this case I obtained a perfectly black product. This was purified and 
 dried, and when digested with spirits of wine, gave the mauve dye.” 
 
 We have in the above quotation another striking example of what 
 very frequently happens in the process of experimental research. A busy 
 worker is striving after the attainment of one definite result, but he 
 obtains one altogether different, and, as in this case, one that turns out 
 to be of very great importance ; and here the great merit lies in being 
 able to perceive at once the different uses to which his discovery can be 
 applied in the arts and manufactures. It often happens that observers are 
 contented to note unlooked for phenomena which they come across, not 
 thinking them worthy of further consideration ; and some one coming after 
 perceives applications, and turns their work to good account. Through, 
 out the history of the coal-tar colours, we perceive the value of carefully 
 recording discoveries, which, though at the time they may be considered 
 trivial, or looked upon as being only important as chemical curiosities, 
 yet as new sources of the product may arise, so may new combina- 
 tions and applications be discovered which may lead to most important 
 results. 
 
328 
 
 COAL-TAR COLOURS. 
 
 Aniline is prepared by mixing nitrobenzol with strong acetic acid and 
 iron filings or turnings. The mixture is made in an iron still, which is 
 afterwards heated by fire or high pressure steam, and the aniline passes 
 over at a temperature between 347° and 374 p Fah. In its commercial state, 
 it is of a pale sherry colour, and gives a blue or blue-violet colour when 
 chloride of lime is added; it combines with sulphuric and hydrochloric acids, 
 producing the sulphate or muriate of aniline. The mauve dye is prepared 
 by mixing a solution of sulphate of aniline with a solution of bichromate of 
 potash. On allowing the mixture to stand for a day or two, a black pre- 
 cipitate is formed — this is collected, washed, and dried, it is then digested 
 in methylated spirit, which dissolves out the mauve dye. The spirit is 
 recovered by distillation, and the mauve solution from the still has caustic 
 soda added to it, which again precipitates the colouring matter. It is now 
 thrown upon a filter and the soda is washed out, leaving the colour in a 
 pasty form, which may be either put into jars for the market in this form, 
 or dried before sending out. W e need scarcely say that when this pro- 
 cess was made public, the attention of chemical manufacturers was at 
 once drawn to it, and numerous improvements suggested. Instead of 
 bichromate of potash, peroxide of lead, peroxide of manganese, perman- 
 ganate of potash, and other oxygenising agents were proposed in order 
 to cheapen the process. The principle of the manufacture is the same 
 in all, so we need not detail them here. 
 
 Mr. Perkin now felt some difficulty in the practical application of the 
 dye to cotton fibre. We quote what he says upon this point — “ The dyeing 
 of cotton with aniline purple at first presented many difficulties ; this 
 colouring matter was found to be capable of producing a very beautiful 
 colour without a mordant, and it was proposed to employ it in this manner; 
 but the colour thus obtained would not bear washing, being nearly all 
 removed with hot water and soap. Mordants, such as alum, were then 
 experimented with, but these gave no results. After some time Mr. R. 
 Pullar accordingly found a method of applying this colouring matter to 
 cotton, which is based upon the insolubility of the compounds it forms 
 with tannin. In using this process, the cotton is first soaked in a decoc- 
 tion of sumach or some other tannin agent, then in a solution of stannate 
 of soda, and lastly in water slightly acidulated with sulphuric acid. The 
 cotton thus prepared -contains an insoluble compound of tin and tannin, 
 and which possesses a great affinity for aniline purple. The stannate of 
 soda may be replaced by alum or a solution of tin salt. This method of 
 preparing cotton has been found suitable for nearly all the aniline colours 
 discovered since the mauve, and is now universally employed in Great 
 Britain for cotton dyeing.” This account of how the difficulties were 
 surmounted is alike interesting to the chemist and dyer, and shews the 
 benefit of practical knowledge. Mr. Perkin again remarks, when speaking 
 of the difficulty of fixing his colour upon cotton — “ I have told you that 
 most of the coal-tar colours contain carbon, hydrogen, and nitrogen, and 
 that they are generally organic bases. They differ essentially from most 
 
COAL-TAR COLOURS. 
 
 329 
 
 of the vegetable colouring matters, which contain, with but few exceptions, 
 only carbon, hydrogen, and oxygen, and are weak acids. You will under- 
 stand that many difficulties had to be encountered in their application for 
 dyeing and printing, because they would not combine with the ordinary 
 mordants used for the colouring matter of woods, as alumina and oxide of 
 tin. The observations refer to the dyeing and printing of vegetable fibres, 
 and not to silk or wool, as these matters absorb the coal-tar colours without 
 the intervention of a mordant.” 
 
 If the reader looks to our remarks upon the colouring matter of the 
 dye-woods, he will find us stating that these have no affinity for cotton, 
 and stand in the same relation to that fibre as the coal-tar colours ; and 
 the practical dyer will not fail to observe that the coal-tar colours are 
 fixed upon the cotton by the same mordants and applied in the same 
 manner as for the colouring matters of Brazil-wood, logwood, &c. — namely, 
 steeping the goods in sumach, then passing them through a solution of 
 chloride of tin, or other tin salt, washing from this, and then passing 
 through the colouring matter. The affinity of the purple colour for 
 animal fibres was so great that it was found difficult to obtain an even dye 
 upon silk and woollen, if the tint required was a light one, the solution 
 becoming exhausted of colour before all the fibre could be exposed to it, 
 and means had to be resorted to for the purpose of retarding the action 
 between the colour and fibre, to enable the dyer to produce light shades 
 with equality. 
 
 Chemists and manufacturers, besides striving to improve the process 
 for producing aniline purple, also sought to produce other colours from 
 the same source, and in this they were wonderfully successful. Shortly 
 after mauve was introduced there appeared an aniline blue. It was pre- 
 pared by mixing a solution of muriate of aniline with one of chloride of 
 lime, which produced a deep blue solution ; the colour was precipitated 
 with common salt and collected upon a filter, any impurities were dis- 
 solved out by washing with cold benzol, and the remaining colour, dissolved 
 in methylated spirit, was ready for use for dyeing silk and woollen fabrics 
 without further preparation. 
 
 The most popular and also the most beautiful colour got from aniline 
 is that known as the magenta. It was first made by heating commercial 
 aniline with tetrachloride of tin, but no sooner was this process known 
 than an improvement was introduced by the substitution of nitrate of 
 mercury for the tin salt ; both these salts, however, had soon to give place 
 to a cheaper and equally effective substitute, arsenic acid. Although 
 many other salts have been tried, this last-named still maintains its 
 ground. Twenty parts of a saturated solution of arsenic acid are mixed 
 with twelve parts of commercial aniline, and heated for some time in a 
 cast-iron still, at a temperature ranging from 3008 to 338 p Fah. ; water and 
 aniline pass over, and when the heat has been continued for some hours, 
 steam is blown through the mixture in the still, which brings over more 
 aniline ; the lid of the still is then removed, and the mixture allowed to 
 
330 
 
 COAL-TAR COLOURS. 
 
 cool sufficiently to be transferred to large vessels, in which it is boiled 
 with an excess of water, and afterwards filtered, to remove insoluble 
 matters. Common salt is then added to the filtrate, which precipitates the 
 colouring matter in a crude form; this is thrown upon a filter, washed, and 
 afterwards dissolved in boiling water ; from this solution the magenta 
 crystallises out on cooling. Chemists have found this magenta to be the 
 salt of a colourless base, called rosaniline. We have referred to similar 
 compounds in the vegetable colouring matter. The formula of rosaniline 
 is given as follows : — 
 
 Anhydrous rosaniline, . . . C 20 Hi 9 1^3. 
 
 Hydrous rosaniline, .... C2oH 19 £7 3 H20. 
 
 When prepared as described above, it is the arseniate of rosaniline ; but in 
 the process of purification it is converted into the hydrochlorate, which is 
 the commercial salt. If prepared with nitrate of mercury the nitrate of 
 rosaniline is formed. The vegetable acids also form salts with this base, 
 so that we may have the acetate or oxalate of rosaniline, &c. 
 
 Magenta, like mauve, has so strong an affinity for animal fibres, that 
 no mordant is required for dyeing silk and woollen. Cotton, however, 
 requires the same mordants as for mauve ; few colours, if any, exceed the 
 rich beauty of magenta, but, unfortunately, it does not withstand the 
 action of light well, and fades on being exposed to it. 
 
 From the salts of this rosaniline base or magenta several other 
 colours have been prepared ; in fact, it is now largely manufactured as a 
 material for the production of those other colours. We have already 
 referred to a blue, prepared by the mixing aniline with chloride of lime ; 
 but another, and the more common blue of the coal-tar colours, is pro- 
 duced by heating a mixture of aniline and magenta. The process is 
 generally conducted as follows : — The mixture is put into iron pots, 
 enamelled inside, and fitted with tight lids, each having a stirring 
 apparatus and condensing tube attached, and a test-hole fitted with a 
 plug. Acetate of soda is introduced with the mixture, as it is found that 
 the best blues are obtained when the salt of rosaniline contains a weak 
 acid. These pots are heated in an oil-bath, and kept at a temperature of 
 370 Q to 375° Fah., until the desired change has taken place. This is 
 ascertained by dipping a glass rod through the test-hole, at short intervals 
 of time, till the desired depth of colour appears on the rod ; the mixture 
 is then removed from the pots, and treated several times with hydrochloric 
 acid, which removes free aniline and purple products, leaving an insoluble 
 mass, which constitutes the cheapest form of this blue. A better blue is 
 obtained by digesting the pasty crude colour in methylated spirit, and 
 throwing the mixture into water acidulated with muriatic acid ; the colour 
 then precipitates, and may be collected upon a filter. This blue is 
 insoluble in water, but, like indigo, it is soluble in strong sulphuric acid, 
 and is thus rendered applicable as a dye. Modifications and improvements 
 in the production of this colour have occurred from time to time, and that 
 
COAL-TAR COLOURS. 
 
 331 
 
 known as “Nicholson’s blue” is the most extensively used. Mr. Nichol- 
 son, however, has not made his process known. This blue has now all 
 but superseded all others, owing to its quality as a dye being superior in 
 distinctness ; for if a light shade is dyed upon woollen or silk with either 
 indigo or Prussian blue, it has generally a greenish or greyish tint ; whereas 
 with Nicholson’s blue, no matter how light the shade, the colour is always 
 distinct ; but, alas, it lacks the permanency of indigo blue, and although 
 the colour is more pure and brilliant at first, its use for dyeing articles of 
 a lasting description, such as carpets, &c., will have to give place to the 
 more permanent colours from indigo-. 
 
 Another blue, called “ Bleu de Paris,” is made by heating aniline with 
 tetrachloride of tin in a close vessel for about thirty hours, at a tem- 
 perature of 360 Q Fah. The blue obtained by this process differs from 
 aniline blue in being soluble in water, but its preparation is difficult and 
 expensive, and it has never attained any position in the market. 
 
 There are also a number of shades of violet prepared from aniline, and 
 largely used by dyers. They differ in tint and shade, according to the 
 process of manufacture. That known as “violet imperial” is produced by 
 heating a mixture of magenta and aniline for a shorter time than is neces- 
 sary to produce the blue already described ; but the most beautiful violet 
 colours are those known as “Hofmann’s violets.” These are obtained by 
 heating together hydrochlorate of rosaniline dissolved in alcohol and iodide 
 of ethyl or methyl for several hours. The mixture is heated in a steam- 
 jacketed iron pot with a tight fitting lid, having a hole which can either be 
 closed with a screw plug or connected with a condensing apparatus ; when 
 the steam has passed through the jacket for five or six hours, the screw 
 plug is removed and condenser attached ; the alcohol and any iodide of 
 ethyl or methyl not taken up distil over. The product is then removed 
 from the pot, dissolved in water, filtered, and* the colouring matter is pre- 
 cipitated from the filtrate with common salt. The violet obtained varies 
 very considerably in tint, according to slight modifications of the process 
 the different tints have different chemical constitutions, as may be seen 
 from the following formulae : — 
 
 These violets are exceedingly brilliant, but, like the other aniline colours, 
 they do not stand exposure to light well. 
 
 Greens. — There is a green, called “ Aldehyd green,” which derives its 
 name from the circumstance that aldehyd is used in its preparation. 
 Aldehyd is a product of the decomposition of alcohol, and is prepared by 
 heating together alcohol, sulphuric acid, and finely divided black oxide of 
 manganese. It is a volatile colourless liquid, with an ethereal yet suffocating 
 
 A red shade, 
 A'reddish-violet shade, 
 A very blue, 
 
 
332 
 
 COAL-TAR COLOURS. 
 
 odour. The aldehyd green may be prepared as follows: — In a mixture of 
 three parts of sulphuric acid and one part of water dissolve one part of 
 magenta, and to the cold solution add in small quantities at a time about 
 one and a-half parts of aldehyd. The temperature of the mixture is then 
 raised to about 212° Fah., and kept at this until a drop of it, placed in 
 water, gives a bright blue colour. It is then thrown into a weak boiling 
 solution of hyposulphite of soda. The quantity of hyposulphite must be 
 four times as much as there was of magenta used. The whole is kept 
 boiling for some time, and then filtered. A solution of acetate of soda is 
 added to the filtrate, which precipitates the green dye, which is caught 
 upon a filter, washed and dried, or used in the pasty condition. By certain 
 modifications of the Hofmann violet process another green may be obtained, 
 which is called the “ iodine green.” It is prepared by mixing one part of 
 rosaniline with two parts of iodide of methyl and two parts of methylic 
 alcohol, and proceeding in the same way as described for Hofmann’s 
 violets, being careful not to allow the heat to exceed 320° Fah. Above 
 this temperature a further decomposition takes place, and the green colour 
 is destroyed. After about five hours heating, the mixture is boiled with 
 a large quantity of water, which dissolves out the green colouring matter, 
 the insoluble is separated by filtration and common salt added to the 
 filtrate. This is again boiled, and carbonate of soda is now added. In 
 filtering a little of the mixture a clear green filtrate is obtained. The whole 
 is then thrown upon a sand filter, and picric acid added to the filtrate, which 
 throws down the green colouring matter as a precipitate, ready for collecting 
 on a filter, washing and using. 
 
 There is another green, called “ Perkin’s green,” which is extensively used 
 in calico-printing. It is prepared in nearly the same manner as the one 
 just described, only there is no iodide of ethyl used. Indeed, so great is 
 the variety of colours and tints which have been produced from the coal-tar 
 products, many of them resulting from slight variation of one process, that 
 it would not only occupy too much space, but would be apt to become 
 tedious, were we to enter into a detailed description of all the different 
 modifications of the manufacture. Every shade of colour between yellow 
 and orange, between blue and purple, and between brown and black, is 
 already known. 
 
 Aniline black is produced by the action of oxidising agents on aniline 
 and toluidine. In appearance it closely resembles the precipitate formed 
 in the preparation of mauve with aniline and bichromate of potash ; but the 
 bichromate is substituted by oxide of copper. The dye is not considered 
 to be definite, but is supposed to be a mixture of at least two colouring 
 matters — one a deep blue, and the other a brown. It is insoluble in water, 
 alcohol, or benzol, and consequently makes a very fast dye. It is more 
 suitable, however, for the calico-printer than the dyer, and, unlike all the 
 other coal-tar colours, it has a stronger affinity for cotton fibre than for 
 woollen or silk. It may be as well to state here how a dye-stuff so insoluble 
 in ordinary solvents is rendered applicable to dyeing and calico-printing. 
 
COAL-TAR COLOURS. 
 
 333 
 
 Several patents have been secured for its application, and we quote what 
 follows from one : — 
 
 “ I take 1 gallon of water, and dissolve in it 4 oz. of chlorate of 
 potash. To this I add aniline in the proportion of 8 oz., previously- 
 mixed with 8 oz. of hydrochloric acid, at 32° Twad. After stirring well, 
 I add 1 pint of acetic acid, and 8 oz. measure of perchloride of copper, at 
 88° Twad. Then I add 4 oz. of sal-ammoniac. I steep the fibre in this 
 solution, wring out and dry ; then I expose the goods in a room at from 
 60° to 70° Fah., for two or three days. The goods are now passed 
 through water alone, or a solution containing alkaline or metallic salts, 
 which develops the black much sooner and better. The alkaline, or 
 alkaline earths, may be used for raising the black, such as caustic soda, 
 potash, ammonia, or lime-water.” 
 
 From the time that the mauve-dye was first discovered on to the pre- 
 sent, we have had a regular progressive succession of discoveries. Chemists 
 have been striving to produce from the numerous products of coal tar 
 colouring matters to rival or surpass in beauty those formerly obtained 
 from vegetable sources only; and the result of their labours may be 
 guessed when we consider the steady development of their discoveries, 
 and of the industrial appliances which were the immediate consequences. 
 These achievements may be said to have reached a culminating point in 
 the production of artificial alizarin — the colouring matter of madder — the 
 synthetical preparation of which had for a long time been the aim of many 
 investigators in this branch of inquiry, and therefore the steps leading to 
 its discovery have a particular historical interest. As early as 1832 Dumas 
 and Laurant, two great French chemists, found, when fractionating the 
 products of the distillation of coal tar, a substance among the heavier 
 portions having carbon and hydrogen in such proportions as to suggest to 
 them the formula of Ci 5 Hi 2 ; and this being about half as much more than 
 a compound previously separated, and known as naphthaline, they gave to 
 this new body the name of paranaphthaline. The same substance was 
 afterwards separated by another chemist, who called it anthracene. The 
 late Professor Anderson, when investigating the coal-tar products, gave as 
 the constitution of this substance Ci 4 H 10 , and he adopted the newer name 
 anthracene, which it still retains. It was for a long time supposed to be 
 one of the useless products of coal tar ; but in 1868 two German chemists 
 — Graebe and Liebermann — when experimenting upon alizarin from madder, 
 found that they could convert the alizarin into anthracene. The question 
 naturally suggested itself, Can anthracene, on the other hand, be converted 
 into alizarin? and ere long these two chemists solved the question by 
 actually preparing alizarin from anthracene, though by a roundabout 
 process. We may here mention, in the discovery of this artificial alizarin, 
 doubts were entertained of its ever becoming commercially useful. Diffi- 
 culties were pointed out similar to those which met the aniline colours on 
 their first introduction, such as the production of anthracene in sufficient 
 quantity, and at a price which would enable the artificial to compete with 
 
334 
 
 COAL-TAR COLOURS. 
 
 the natural alizarin. Then there was considerable difficulty in separating 
 pure anthracene from the other solid products of coal tar, a list of which 
 we give below, with their melting and boiling points and their formulae : — 
 
 Naphthaline, 
 
 Formula. 
 
 . C 10 H 8 
 
 Melting point. 
 
 79° Fah. 
 
 Boiling point. 
 
 220° Fah. 
 
 Acenaphth aline, . 
 
 . c 12 h 10 
 
 0 
 
 o 
 
 o 
 
 i— i 
 
 99 
 
 285° „ 
 
 Phenanthrene, 
 
 . C 14 II 10 
 
 110° 
 
 99 
 
 340° „ 
 
 Anthracene, 
 
 . c 14 H 10 
 
 213° 
 
 „ ‘ 
 
 360° „ 
 
 Pyrene, 
 
 • C 16 H 10 
 
 180° 
 
 9 9 
 
 
 Chrysen, 
 
 . Ci 6 H 10 
 
 284° 
 
 99 
 
 360° „ 
 
 Retene, 
 
 . c 18 h 18 
 
 95° 
 
 9 » 
 
 400° „ 
 
 The reader will observe that anthracene and chrysen have the same 
 boiling points, and will in consequence distil over together, so that the 
 separation cannot be effected by fractional distillation ; it may, however, 
 be performed by dissolving the anthracene in spirits of wine, chrysen 
 being insoluble therein. 
 
 It was found that when anthracene is heated with glacial acetic acid 
 until the mixture gently boils, and chromic acid added at intervals, keeping 
 up the ebullition for about two hours, that, on cooling, there is deposited 
 a crop of light-coloured crystals. These gave, on analysis, a formula of 
 C 14 H 8 0 2 , and this substance was termed anthrachinon. It may be pre- 
 pared more easily by mixing one part of anthracene with two and a half 
 parts of bichromate of potash in solution, and four parts of wood vinegar. 
 When these have been heated for some time together, a mixture of six 
 parts strong vitriol, with two of water, is added by degrees, keeping the 
 temperature at 212° until all action has ceased. If the anthracene has not 
 been pure, the product obtained as above is dissolved in oil of vitriol, and 
 heated to 158° Fah., until sulphurous acid gas ceases to be evolved. It is 
 then thrown into water, and the anthrachinon, which is insoluble in water, 
 is precipitated and obtained by filtration. This substance forms a sort of 
 link between anthracene and alizarin, as may be seen from their respective 
 formula : — 
 
 Anthracene, ....... C 44 H 10 . 
 
 Anthrachinon, C 14 H 8 0 2 . 
 
 Alizarin, c 14 h 8 0 4 . 
 
 Notwithstanding the evident close relationship of the two last com- 
 pounds, there is no direct method of giving to the anthrachinon the two 
 equivalents of oxygen necessary to complete the change ; but, again, by a 
 somewhat roundabout method this has been achieved, and after its accom- 
 plishment several methods were suggested and patented, all more or less 
 successful. Graebe and Liebermann patented the following process : — 
 The anthracene is treated with bromine or chlorine, and the product fused 
 with caustic potash, which yields an alizarate of potash ; this is decom- 
 posed by muriatic acid, and chloride of potassium and alizarin are 
 
COAL-TAR COLOURS. 
 
 335 
 
 obtained. These chemists afterwards substituted another process. They 
 treated the anthrachinon with vitriol, precipitated any excess of acid with 
 lime, then to the clear solution they added carbonate of soda, and eva- 
 porated this to dryness; they then fused the dry mass with caustic soda 
 and from this obtained the alizarin. While these experiments were 
 being carried on by continental chemists, Perkin, Dale, and others in 
 this country were prosecuting similar investigations, which resulted in 
 the preparation of alizarin from anthracene without the necessity of 
 forming the intermediate compound, anthrachinon. Their processes con- 
 sisted at first of either treating the bromine or chlorine compounds of 
 anthracene with sulphuric aeid and peroxide of manganese, or boilino- the 
 anthracene with sulphuric acid, precipitating the excess of acid by lime, and 
 treating the remaining solution with caustic potash and nitrate, or chlorate 
 of potash, supplying the required oxygen. These processes have been 
 greatly simplified, and have cheapened the production of artificial alizarin 
 several modifications have also been introduced from time to time, as 
 
 experience was gained in manufacturing, but these have not been made 
 public. 
 
 For some time considerable donbt was entertained as to the identity 
 of the composition of artificial alizarin with that of the natural ; but careful 
 analysis by Dr . Schunck, Messrs. Perkin, Bolley, Kopp, and others haye 
 lemoved all donbt, and established their identity. It was also uncertain 
 at first whether the artificial would be equally valuable in the dye-house or 
 not, and it was more difficult and required a longer time to remove the 
 doubts and prejudices on this point. A little time and experience were 
 sufficient to prove the efficacy of the dye to those of an unbiased iud<-- 
 ment; but the prejudice resulting from the long use of madder, and the 
 influence brought to bear by the madder growers and merchants whose 
 interests were at stake, have not been entirely removed yet. All those 
 however, who have given the artificial alizarin a fair trial have found that 
 the red produced IS equally fast and brilliant with that given by madder 
 and the principal contention now is a commercial one-one of £ s. d.’ 
 
 . en i GVer arti , ficial colours can be produced and sold to the dyer at a 
 Sch7r ha “ th n natUraI ’ the latter mu8t yield - Notwithstanding this, 
 k ne f hTT PHt madder quite 0Ht ® f the market i for th « latter 
 
 whih tTe r t T y ° ^ UP ° n W00 ‘: b6CaUSe ifc conteins other dyes 
 
 furthe ,. W °° . a 68 U P’ § lvln 8 tints which pure alizarin does not; but 
 further discoveries may soon overcome this difference. The reader will 
 ave seen that mauve and magenta were only the first of a series of new 
 dyes, so also may alizarin yet turn out to be; and should there develop 
 
 result wil^biTof th 861168 ° f flours with the permanency of alizarin, the 
 Indeed f , lm P ortan “ *0 the dyeing and calico-printing 
 trades. Indeed we have already indications of such a series. Mr Perkin 
 
 has announced that when experimenting upon alizarin, he found that there 
 produced, along with that colouring matter, another which gave 
 certain reactions differing from alizarin : it gave, with the same mordants 
 
336 
 
 COAL-TAR COLOURS. 
 
 a bluer purple and a more scarlet red ; and to this colouring matter he has 
 given the name of anthrapurpurin, and its formula as C 14 H 8 05 . He 
 separated this anthrapurpurin from crude alizarin by dissolving the latter 
 in a dilute solution of carbonate of soda, and adding precipitated alumina, 
 which, on agitation, combined with the alizarin, forming a lake, which 
 precipitated and left the anthrapurpurin in solution ; he boiled this clear 
 solution, and acidified with hydrochloric acid, which caused the colouring 
 matter to be precipitated. Mr. Perkin says this colouring matter is still 
 associated with another, which gives an orange colour with aluminous 
 mordants. By repeated boiling in alcohol this orange colouring can be 
 removed from the anthrapurpurin. These processes of separation are yet 
 difficult, but hopeful; the orange colouring matter has not yet been sub- 
 jected to analysis. The following is some of the properties and reactions 
 of anthrapurpurin : — It is very slightly soluble in water ; caustic potash 
 and soda dissolve it, giving beautiful violet-coloured solutions, which 
 become blue when heated, but not so blue as those obtained with alizarin ; 
 it dissolves also in solutions of the alkaline carbonates, giving a reddish- 
 purple colour, which is precipitated with carbonic acid. If a solution of 
 it in alcohol have acetate of copper added, the colour changes from a 
 yellow to a beautiful purple. When an ammoniacal solution of it is acidified 
 with hydrochloric acid, the dye is precipitated as a dark purple, which 
 dissolves in carbonate of soda, yielding a blue colour; and in caustic 
 alkalies yielding a reddish -purple. Mr. Perkin says that anthrapurpurin 
 has about the same affinity for mordants as alizarin ; the colours it pro- 
 duces are also, to some extent, analogous, for it dyes red with alumina, 
 purple and black with iron mordants. There is, however, he observes, a 
 considerable difference in the shade of colour produced, the red being 
 much purer and less blue than those of alizarin, and the purples, blues, and 
 blacks more intense. The fastness of the colours against light and soap is 
 equal to that of the alizarin colours. When used in dyeing Turkey-red it 
 produces very brilliant colours of a scarlet shade, which are remarkable 
 for their permanence. 
 
 These results are most hopeful to the dyeing trade, but we have our 
 fears as to the resultant effects which will be produced on the dyer as an 
 intelligent and skilled workman. Hitherto the art was one which required 
 for its successful operations a considerable amount of skill and experience 
 in comparing the dyes and judging of the effects produced by different 
 combinations of the dyeing agents and tints, so as to procure the desired 
 shade, so that a good practical dyer was a man with a degree of intelligence 
 which enabled him to command a position equal to that of a skilled me- 
 chanic. But when every colour and shade of colour is made to his hand, 
 and it is only necessary for him to put in the required quantity, and work the 
 goods in it till the proper depth of colour is obtained, less intelligence is re- 
 quired, a less intelligent class of men will be employed, and very little im- 
 provement will result from the operations of the trade. Mr. Perkin has 
 considered this view of the question, and has gone somewhat further than the 
 
COAL-TAR COLOURS. 
 
 337 
 
 effects upon the working dyer. We quote what he says on this point:— 
 “ The aniline colours have produced quite a revolution in the arts of dyeing 
 and printing, and have made these processes far simpler than they were, 
 and there is such a variety of shades of colour now sent into market, that 
 the dyer or printer has little else to consider than the intensity of the colour 
 required ; and, in fact, if a dyer has a large order to execute of a particular 
 shade of colour not in the market, he will not trouble about matching it 
 himself, but send to the colour manufacturer to supply him with a product 
 capable of yielding the required shade.” 
 
 We have here the opinion of a great discoverer in this branch of 
 industry, who is perhaps apt to look upon these discoveries, and represent 
 them as a source of saving all manner of trouble to the manufacturing 
 dyer. There is no doubt they will lessen the bother and chance of error 
 to a very large extent ; but though we perceive the inevitable lowering of 
 the workmen’s qualifications, there will still be required about as great 
 skill and experience as ever in the manufacturer or manager to enable him 
 to suit the colouring matter to the fabric. Cotton, woollen, and silk, as we 
 have already stated, require different treatment, and different qualities 
 of the same kind of fibre will not give the same results on dyeing. Then, 
 again, different qualities and strengths of mordants will give different results, 
 and unless the colour manufacturers were furnished with all these parti- 
 culars accompanying every order, and were experienced practical dyers to 
 boot, the dyer could never depend on having his pattern suited or matched 
 without giving his practical supervision and care, and exercising his skill 
 and experience as formerly. 
 
 Y 
 
DYEING RECEIPTS. 
 
 INTRODUCTORY OBSERVATIONS. 
 
 In the preceding pages we have endeavoured throughout to consider the 
 wants and requirements of the practical man from a chemical stand- 
 point, and therefore have confined our remarks more to the principle 
 and the theory of the operations, than to the operations themselves ; and 
 when making reference to practical processes, we considered ourselves ad- 
 dressing men equally conversant with the process under consideration with 
 ourselves. Consequently, except when required to illustrate some funda- 
 mental principle, practical processes for dyeing have not been given. But 
 our present object is to detail processes, and in so doing we do not now 
 consider ourselves writing for practical dyers, nor do we, in every case, 
 profess to give the most recent and economical methods for a dye-house. 
 A receipt that is the best and most economical to-day may not be so to- 
 morrow, from modifications and improvements introduced as the result of 
 observations, depending, it may be, upon circumstances which no receipt 
 can give. In what follows we are supposing ourselves addressing the non- 
 practical reader, or, it may be, the apprentice-dyer, and therefore descend 
 into details of processes, so that any one may be enabled to produce, either 
 for amusement or use, any of the shades or colours required. And 
 although, as already stated, the quantities and particular methods given 
 may not be, in all cases, the most economical for the dye-house, neverthe- 
 less, by carefully following out the instructions given, a good colour 
 similar to the pattern attached will be produced without difficulty, which 
 is all that is in general required by the amateur. The practical dyer will 
 soon economise according to circumstances, while the thrifty housewife will 
 find that very little trouble is necessary for renovating and improving the 
 appearance of many articles of dress and house furnishings, either in 
 cotton, silk, or woollen. 
 
 At the same time, it may be stated that many of the manipulatory 
 processes to be given refer to the methods followed in the dye-house, 
 either of hank or cloth ; but where small quantities of goods are to be 
 dyed, what is required in the operations is the free exposure of every 
 portion or part of the fibre, whether cloth or skein, to the dyeing solution, 
 and particularly to the mordant. Where a mordant is required, if the 
 mordant be not equal upon the fibre an even dye cannot be got. 
 
PRELIMINARY PREPARATIONS. 
 
 339 
 
 PRELIMINARY PREPARATIONS FOR DYEING. 
 
 1. Banding. 
 
 Cotton is generally obtained in bundles of 5 lbs. or 10 lbs., made up 
 of heads , each head having 10 hanks, except when the yarn is very coarse, 
 when each head has only 6 hanks ; or very fine, when each head has 20 
 hanks. The number of heads indicates the grist of the thread, called “ the 
 Number.' 1 ' Thus, 10 lbs. of No. 60 will have 60 heads of 10 hanks, or 30 
 heads of 20 hanks. These heads are made up into spindles of 18 hanks 
 by the dyer, and through each spindle is tied a piece of stout thread or 
 twine, termed a band ; the bundle, when banded, is divided into six quan- 
 tities, and rolled up and tied into bundles for boiling. Thus, No. 60 will 
 give 35 spindles and 12 hanks, equal to 36, and will be rolled up into 
 6 sixes, or all sixes, as it is termed, 10 lbs. being invariably named a 
 bundle. 
 
 Silk is also banded in the same manner as cotton, using no par- 
 ticular number of hanks, but in quantities convenient for making up into 
 skeins when finished. 
 
 Woollen is also banded with twine into spindles, previous to being 
 put under operations for scouring or dyeing. 
 
 2. Boiling and Sticking. 
 
 Cotton .— After banding, cotton is boiled in water for two or three 
 hours until thoroughly wet (see page 56). The bundles are then loosed, 
 and each roll of yarn is put upon a wooden pin, about 3 feet in length and 
 about l£ inch thick, six pins or sticks forming a bundle according to the 
 division made by the bander. The pins are put through the hank. 
 
 Silk, as referred to in No. 1, after banding, is carefully tied up and 
 put into fine canvas bags, and boiled in the bags in a strong solution of 
 soap for three or four hours, until all the gum is boiled off. If the silk be 
 yellow gum, it is put upon sticks like the cotton, and wrought in a solution 
 of soft soap, at a temperature just approaching the boiling point, for about 
 one hour, when it is tied up as the white gum silk, and put into bags and 
 boiled till all the gum is removed ; when boiled, it is washed from the 
 soap, and sticked for dyeing, putting six or eight heads of silk on each 
 stick. 
 
 Woollen is steeped over night in soap ley, or old alkaline solutions, 
 and then scoured through clean soap, to remove all oil or grease that may 
 be upon the wool ; or, what is more common, a scouring liquor is prepared 
 with 1 lb. soft soap and 1 lb. common soda, or £ lb. soda ash, in 10 
 gallons water, and scoured through this. 
 
 3. Cotton Cloth. 
 
 The cloth is taken out the fold and hanked up by the hand, taking the 
 end of the piece through the hank and tying it loosely, technically termed 
 
340 
 
 DYEING RECEIPTS. 
 
 kinching ; it is then steeped in old alkaline ley overnight, which loosens 
 and removes the oil, grease, and dressing which it has got in weaving ; it 
 is then thoroughly washed in clean water. Where there is a dash wheel, 
 it should be used for this washing. This liquor often ferments with the 
 dressing on the cloth, hence it is known as the rot steep. 
 
 4. To remove Oil Stains. 
 
 When oil spots are upon the goods, and so fixed or dried in that the 
 steeping, as above, will not remove them, rub a little soft soap upon the 
 oil stain, and let it remain for an hour, then rub the stain gently with the 
 hand in a lather of soap, slightly warmed, and then wash in water ; 
 for cotton, a little caustic ley will do equally well for removing the oil, 
 but the soap is a preferable process, and seldom fails. It is essential that 
 all oil or grease be removed before dyeing. 
 
 5. To remove Iron Stains. 
 
 Take a little muriatic acid in a basin or saucer and make it slightly 
 warm, by placing the basin in hot water, then dip the iron stain into the 
 acid for about one minute, which will dissolve the oxide of iron ; the 
 cloth must be well washed from this, first in water, then in a little soda 
 and water, so as to remove all trace of acid. A little oxalic acid may 
 be used instead of muriatic acid, but more time is required, and with old 
 fixed spots is not so effective. The same precautions are necessary in 
 washing out the acid, as any acid dried in the cloth injures it. 
 
 6. To make Bleaching Liquor. 
 
 Take a weighed quantity of bleaching powder, and add to it as much 
 water as will make it into a thin cream ; take a flat piece of wood and break 
 all the small pieces by pressing them against the side of the vessel, then 
 add two gallons of cold water for every pound of powder ; stir well, put a 
 cover upon the vessel, and allow the whole to settle. This will form a 
 sort of stock vat for bleaching operations. 
 
 7. To bleach Cotton Yarn for Dyeing. 
 
 A vessel sufficiently large to allow of the cotton being wrought in it 
 freely without pressing is to be filled about two -thirds with boiling water ; 
 add a pint of bleaching liquor from No. 6 for every gallon of water in the 
 vessel, then work the yarn in this for half an hour. Into another vessel 
 of similar size, filled two-thirds with cold water, add a wine-glassful of 
 vitriol for every two gallons of water ; stir well, and then put the yarn 
 from the bleaching solution into this, and work ten minutes, and then wash 
 rom this until all acid is removed. 
 
PRELIMINARY PREPARATIONS. 
 
 341 
 
 8. To work Cotton Yarn for Dyeing or Bleaching for Dyeing. 
 
 A bundle, No. 2, suspended upon the pins, is put into a tub filled 
 with the liquor; the ends of the pins resting upon the edge of the tub, the 
 lower portion of the yarn is in the liquor, the upper portion is over the 
 pins. The workman now catches the part of the yarn that is upon the pin 
 and draws it right over, so that the position of the hank is reversed — that 
 which was above is now in the liquor, and vice versa. When he has gone 
 over the whole bundle, he draws the whole towards him and begins anew, 
 and this goes on until the liquor (if it be dyeing) is pretty well exhausted ; 
 by this means the whole yarn is completely exposed. In the dye-house, in 
 dyeing 10 lbs., low tubs, about 20 inches in height and as many wide, are 
 used, and called 10 lb. -tubs ; but any vessel may be used that holds liquor 
 enough to allow the yarn easy play. For larger quantities of yarn long 
 boxes are used, having a steam pipe along the bottom to keep up the heat 
 of the solution. These are termed baths. 
 
 9. To bleach Cotton Yarn to be finished White. 
 
 The yarn when banded is boiled for three hours in caustic ley, either 
 potash or soda, made by adding one gill of the caustic ley No. 11 or 12 for 
 each gallon of water in the boiler ; wash well from this ley, and lay the 
 yarn to steep in a bleaching liquor, made up as No. 7, but with cold water; 
 after four or five hours, lift and steep for an hour in a sour of one wine- 
 glassful of vitriol to the gallon of water, lift and wash well ; then boil again 
 in a ley of half the strength of the first for two hours, and wash from this 
 and steep again four hours in bleaching liquor ; wash from this and steep 
 for an hour in a clean sour ; wash well from this and dry. A little smalt 
 blue is put into the last washing water to clear the white- 
 
 10. To bleach Cotton Cloth. 
 
 Rot steep, as No. 3, and wash, then boil in caustic ley, of the strength 
 of 1 gill of No. 11 or 12 to the gallon of water, for three hours ; wash out 
 the boil and steep in bleaching liquor for six hours, same strength as No. 
 9 ; wash, and steep an hour in strong sour of one wine-glassful of vitriol 
 to the gallon of water ; wash well from this before drying or dyeing. If 
 the cloth be very heavy, one operation may not be enough ; in such cases 
 repeat the operation, omitting the rot steep. 
 
 11. To make Caustic Potash. 
 
 To 3 gallons of water add 2 lbs. either black or pearl ashes and boil ; 
 when boiling, add newly slaked lime, until a small quantity of the liquor 
 taken out does not effervesce when an acid is added to it. To do this, 
 take a tumbler half filled with cold water, take out a tablespoonful of the 
 boiling ley, and put into the tumbler, and add a few drops of sulphuric 
 acid ; were sulphuric acid added to the hot ley, it would spurt up, and 
 
342 
 
 DYEING RECEIPTS. 
 
 endanger the operator. When the addition of acid causes no effervescence, 
 the boiling and adding of lime is stopped, and the whole allowed to 
 settle ; then remove the clear into a vessel having a cover, to prevent it 
 taking carbonic acid from the air. This serves as a stock for general use. 
 The lime sediment remaining may have some hot water added, which will 
 give a strong ley, and may be used for first boils for yarn or heavy cloth. 
 
 12. To make Caustic Soda. 
 
 For every gallon of water add 1 lb. of soda ash, or 2 lbs. of crystal- 
 lised soda of the shops ; boil, and then add slaked lime, and proceed 
 otherwise as with No. 11. 
 
 13.. To slake Lime. 
 
 Take some well and newly-burned limestone, and pour over it some 
 water so long as the stone seems to absorb it, and allow it to stand ; if not 
 breaking down freely, sprinkle a little more water over it. A small quan- 
 tity is best done in a vessel, such as an old cask, in which case it may be 
 covered with a board or bag. Slaked lime should not stand long exposed. 
 One cwt. of newly -burned Irish lime will take 4 gallons water. 
 
 14. To make a Sour. 
 
 To every gallon of water add 1 gill of vitriol, or gill of muriatic 
 acid, stir thoroughly ; goods steeped in this should be covered with the 
 liquor, as pieces exposed become dry, which deteriorates the fibre ; if left 
 under the liquor, the cloth is not hurt by being long in the sour. 
 
 15. To make Nitrate of Iron. 
 
 Take four parts, by measure, nitric acid (aquafortis), and one part 
 water, put the vessel containing the mixture into a warm place, and add by 
 degrees pieces of iron so long as the acid continues to dissolve the metal 
 with effervescence ; then take out any remaining iron, and after settling 
 for an hour, pour off the clear, and preserve from light. The solution 
 has a brownish colour and syrupy consistence. 
 
 N.B. — The fumes- given off during the operation destroy animal and 
 vegetable tissues, and corrode metals. They should be led up the chimney. 
 The strength of the acids used in these receipts, except otherwise men- 
 tioned, is — 
 
 Vitriol, 166° to 168° Twad. 
 
 Nitric acid, ..... 63° ,, 66° ,, 
 
 Muriatic acid, .... 32° ,, 35° „ 
 
 16. To make Acetate of Iron {Black Iron Liquor). 
 
 Put pieces of iron, or filings, into crude vinegar, and allow it to stand 
 for several days, stirring occasionally ; a gentle heat assists the action. 
 
 This liquor is sold prepared, and may be obtained of any drysalter. 
 
PRELIMINARY PREPARATIONS. 
 
 313 
 
 17. To make Sulphate of Iron {Copperas). 
 
 Into a glass or stoneware vessel put two parts, by measure, of sul- 
 phuric acid (vitriol), and one part water, and add small pieces of iron, or 
 filings, as long as they are dissolved ; then decant the clear liquid into a 
 basin, and evaporate by a gradual heat, until a skin or pellicle be seen 
 forming on the surface of the liquid; remove the heat, and when cool, 
 sulphate of iron will be found crystallised at the bottom. This salt is 
 sold cheap by drysalters. 
 
 18. To make Proto- Chloride of Iron {Muriate of Iron). 
 
 To four parts of muriatic acid add two parts water, and apply a gentle 
 heat, then add iron, in pieces or filings, so long as it continues to be dis- 
 solved, then pour off the clear into a basin and evaporate, as No. 17, when 
 greenish-coloured crystals of chloride of iron will be obtained ; but this 
 salt crystallises with difficulty, and deliquesces in the air, and should not 
 be exposed. Instead of evaporating and crystallising, the solution may be 
 put into a bottle and reserved for use. 
 
 19. To make Persulphate of Iron. 
 
 Take some nitrate of iron, No. 15, and add to it carbonate of soda or 
 potash in solution ; so long as there is a precipitate, wash the precipitate, 
 which is easily done by using a large vessel for the operation, filling it up 
 several times with water, and when the precipitate settles, decanting off the 
 clear ; when washed, some vitriol is added and heat applied, which dissolves 
 the precipitate, and forms persulphate of iron. 
 
 20. Other Methods. 
 
 Take two parts vitriol, and one nitric acid, and two water, and add 
 iron so long; as it is dissolved, applying heat ; take the clear solution and 
 bottle up for use. 
 
 To 4 oz. of copperas, dissolved in water, add £ oz., by measure, of 
 nitric acid, and boil the solution for about one minute. 
 
 Instead of nitric acid, add £ oz. of nitrate of potash (nitre) and a few 
 drops of vitriol ; bring the whole to a boil, when the protosulphate of iron 
 is converted into a persulphate. 
 
 These salts are not generally sold by drysalters. 
 
 The proportions or parts of acids referred to are by measure. 
 
 21. To make Perchloride of Iron {Permuriate of Iron). 
 
 Take three parts of muriatic acid and one part nitric acid, with two 
 parts water, and add iron so long as it continues to be dissolved ; the clear 
 solution is then to be decanted and bottled for use. 
 
344 
 
 DYEING RECEIPTS. 
 
 It may be formed also by precipitating the iron from the nitrate by 
 soda, and dissolving the precipitate in muriatic acid, in the same manner 
 as No. 20. 
 
 22. To make Sulphate of Zinc ( White Vitriol). 
 
 Take two parts vitriol and one part water, and add to the mixture 
 metallic zinc, granulated, so long as it continues to be dissolved ; decant 
 the clear into a basin, and evaporate by heat until a skin appears on the 
 surface, then lay aside to cool, when there will be obtained crystals of 
 sulphate of zinc. They are white and transparent. This salt is very 
 abundant in the market. 
 
 23. To make Sulphate of Copper ( Blue Stone). 
 
 Two parts strong vitriol and one part water are put into a glass flask, 
 there is then added a quantity of copper turnings or filings, and the whole 
 kept boiling for a considerable time ; then decant the solution into a basin, 
 and set aside to cool, when blue crystals of sulphate of copper will be 
 obtained. This salt is plentiful in the market. 
 
 N.B . — The gas given off when making this salt should not be allowed 
 to escape into a room ; indeed, the dissolving of metals in acids should 
 always be done in such situations that the gases evolved be carried up a 
 chimney. 
 
 24. To make Nitrate of Copper. 
 
 To one part, by measure, strong nitric acid and two parts water, add 
 metallic copper so long as the acid dissolves it. The clear solution is put 
 into a bottle and preserved for use. By evaporating, as No. 22, crystal 
 will be obtained, but with difficulty. Dyers themselves generally prepare 
 this salt. 
 
 25. To feather Tin or Zinc ( Granulate ). 
 
 Take the best grain tin, and melt in an iron pot or ladle, and then 
 pour it gently from a height of several feet into a large vessel filled with 
 cold water. The metal is formed into thin flakes, and is in this state easily 
 dissolved. 
 
 Zinc may also be granulated by the same process. 
 
 26. Protochloride of Tin (Crystals of Tin). 
 
 Take three parts pure muriatic acid and one part water, put them into 
 a glass or stoneware vessel, and place it so that the acid be raised to a 
 temperature of nearly 200° ; add to this acid feathered tin from time to 
 time, so long as it continues to be dissolved, then withdraw the heat, and 
 let the solution cool gradually, when there w 7 ill be obtained the crystals of 
 tin, which may be collected and dried at a moderate heat, and bottled 
 tightly to prevent deliquescence. This salt is sold by drysalters. 
 
PRELIMINARY PREPARATIONS. 
 
 345 
 
 27. To make Bichloride of Tin. 
 
 Take 1 oz. of protochloride of tin (crystals of tin) and dissolve in 
 5 oz. of water, in which is put £ oz. muriatic acid ; bring this to boil, 
 adding cautiously, and drop by drop, nitric acid, until no effervescence or 
 nitrous fumes are produced by its addition. Allow to cool, and then 
 bottle for use. 
 
 By heating barwood spirits, or plumb spirits, and treating in the same 
 manner, bichloride will be produced. As the nitric acid put into the spirits 
 causes rapid effervescence, a large vessel should be employed for this 
 operation. 
 
 28. Another method for Permuriate of Tin. 
 
 Take two parts of muriatic acid and one part nitric acid, add to this 
 feathered tin, gradually as dissolved, keeping the acid warm. Red nitrous 
 fumes are evolved in this operation. Three ounces of tin to every pound 
 of mixed acids forms a good spirit. Some dyers, especially for woollen 
 stuff, add to this a little sal-ammoniac, say half the weight of the muriatic 
 acid. 
 
 29. Red Spirits. 
 
 Take three parts, by measure, of muriatic acid and one part nitric acid, 
 with one part water; put the vessel containing the mixture into a cool 
 place, and add, in small quantities at a time, feathered tin, in the pro- 
 portion of 2 oz. of tin for each pound of acid. A few hours after the 
 action has ceased, the spirits are ready for use. 
 
 N.B . — In making spirits, the best sort of vessels to use are salt-glazed 
 stoneware, as thin as can be had. 
 
 30. To make Yellow Spirits. 
 
 To every three parts of muriatic acid add one part sulphuric acid and 
 one part water ; add to this, by degrees, feathered tin, so long as it con- 
 tinues to be dissolved, keeping the solution at a temperature of about 60° ; 
 decant and preserve for use. This kind is seldom used now. The red 
 spirits serve the same purpose. 
 
 31. Barwood Spirits. 
 
 Take five parts, by measure, muriatic acid and one part nitric acid ; 
 add to this, by degrees, 1 oz. of feathered tin for every pound of the 
 mixed acid. This spirit should stand for a day before being used. 
 
 32. Spirit Mordant for Woollen. 
 
 Five lbs. muriatic acid, 3 lbs. sulphuric acid, } lb. nitric acid, 1 lb. 
 tartar, and 2 pints water ; dissolve in this 1 lb. of feathered tin, or as much 
 tin as the acid will dissolve. 
 
346 
 
 DYEING RECEIPTS. 
 
 33. Plumb Spirits. 
 
 Mix six parts, by measure, muriatic acid, one part nitric acid, and 
 one part water ; keep the mixture at a temperature of about 60° ; for every 
 pound weight of the acids add by degrees 1| oz. tin. This spirit should 
 stand a day before being used. 
 
 34. Double Muriate of Tin. 
 
 This is prepared exactly as No. 26, but is not crystallised. Dissolve 
 5 oz. tin in every pound weight of muriatic acid, this gives the strength 
 at which it is generally sold. 
 
 Oxymuriate is prepared by passing chlorine through a solution of 
 muriate of tin. 
 
 35. Single Muriate of Tin. 
 
 Take two parts acid and one part water, and add to this 3 oz. of tin 
 for every pound weight of acid ; dissolve in the same manner as No. 26. 
 
 Both these liquors are sold by drysalters. 
 
 36. To Make a Plumb Tub. 
 
 Make a decoction of logwood by boiling ; if the wood be ground, half 
 an hour’s boiling will do, but if chipped, two hours, using 1^ lb. best 
 logwood for every gallon water ; after boiling has ceased, and the wood 
 settled, decant the clear decoction and allow it to stand for forty-eight 
 hours ; again decant from any matter that may have settled to the bottom, 
 and to every gallon of the decanted liquor add from 1 to 1^ lb. of plumb 
 spirits. Stir well, and after standing for a day it is ready for use. If the 
 spirits were added to the logwood while hot the colour would precipitate. 
 
 37. Alum Plumb Tub. 
 
 Make a decoction of logwood, by boiling, of 1 lb. to the gallon water; 
 when the wood is settled, remove the clear decoction, and to each gallon 
 of liquor add 1 lb. of alum. The alum should be previously dissolved to 
 saturation. When well stirred and allowed to stand for a day, the plumb 
 tub is ready for use. 
 
 38. Peachwood Plumb. 
 
 Make a strong decoction of Lima or Brazil-wood by boiling, using 
 1 lb. wood to the gallon water. When the boiling has ceased and 
 the wood settled to the bottom, decant the clear and allow it to cool 
 for twenty-four hours ; then decant again from any sediment that may have 
 collected, and to every gallon of liquor add half-pint plumb spirits No. 33 ; 
 stir well, and let stand for several hours, when it is fit for use. 
 
 39. To make up a Blue Yat. 
 
 Take 1 lb. of indigo, and grind in water until no grittiness can be felt 
 between the fingers ; put this into a deep vessel (casks are generally used), 
 
PRELIMINARY PREPARATIONS. 
 
 347 
 
 with about 12 gallons of water, then add 2 lbs. copperas and 3 lbs. newly- 
 slaked lime, and stir for fifteen minutes ; stir again after two hours, and 
 repeat every two hours for five or six times ; towards the end, the liquor 
 should be of a greenish -yellow colour, with blackish veins through it, and 
 a rich froth of indigo on the surface. After standing eight hours to settle, 
 the vat is fit for use. The goods should not be allowed to come into contact 
 with the precipitate or sludge at bottom. 
 
 39a. Another Method. 
 
 One lb. indigo, 1^ lb. slaked lime, ^ lb. of fine iron filings, and f lb. of 
 powdered zinc — the zinc must be in the state of an impalpable powder ; stir 
 every hour for five or six hours, until the solution becomes yellow with 
 blue veins through it ; let it stand for half-an-hour, and it is fit for use. 
 
 40. To PREPARE ANNOTTA. 
 
 Into 2 gallons of water put 1 lb. annotta, 4 oz. pearlash, and 2 oz. soft 
 soap, apply heat, stir until the whole is dissolved. When convenient, 
 it is best to boil the solution. 
 
 41. To prepare Catechu. 
 
 To 7 or 8 gallons of water add 1 lb. of catechu, and boil till all is 
 dissolved, then add 2 oz. nitrate of copper, and stir, when it is ready for 
 use. Sulphate of copper may be used instead of nitrate. Any quantity, 
 less or more of each, may be used in the same proportions. 
 
 42. To make Decoctions of Ground Woods. 
 
 On a piece of coarse cloth stretched upon a frame, or laid into a 
 basket, put the ground wood, and place it over a vessel, then pour over 
 the wood boiling water until the water pass through nearly colourless. If 
 the wood be chipped it must be boiled. 
 
 43. TO TEST THE COMPARATIVE QUALITY OF LOGWOOD, OR OTHER 
 Vegetable Colouring Matters Soluble in Water. 
 
 Take 100 grains, and dry at the heat of boiling water, and mark the 
 loss. Take 10 grains and put into a porcelain crucible, and keep it at a 
 red heat over gas or in a clear fire until nothing is left but a white ash ; 
 weigh this and mark. Take other 10 grains and put it upon a filter, and 
 pour boiling water upon it as long as the water passing through is 
 coloured; dry what remains on the filter at 212° and weigh; this gives 
 water, ash, and woody fibre. Then take a skein of cotton of a given weight 
 mordanted with sumach and spirits ; work this in the colour dissolved out 
 until the liquor is exhausted. When several samples of logwood are tested, 
 their relative values are thus easily ascertained. We use only 10 grains 
 
348 
 
 DYEING RECEIPTS. 
 
 to test for the colouring matter, as it is important that the colour should 
 never be sufficient to dye the cotton fully. We have found the quantity of 
 moisture given off at 212® from ground logwood to vary from 27 per cent, 
 to 45 per cent. Red and yellow woods may be tested in the same way. 
 
 44. To make Sulphate of Indigo. 
 
 Into 5 lbs. of the most concentrated sulphuric acid, not less than 168® 
 Twad., stir in by degrees 1 lb. of the best indigo, finely ground and dried ; 
 expose this mixture to a heat of about 100° Fah. for ten or twelve hours, 
 stirring it occasionally. A little rubbed upon a window pane should 
 assume a purple-blue colour. 
 
 45. To prepare Indigo Extract. 
 
 Sulphate of indigo is prepared as No. 44, and then diluted with about 
 4 gallons of hot water, and the whole put upon a thick woollen filter over 
 a large vessel, and hot water poured upon the filter until it passes through 
 nearly colourless ; the blackish matter retained upon the filter is thrown 
 away, and the solution which passed through is transferred to a leaden vessel, 
 and evaporated to about 3 gallons, to this is added about 4 lbs. common 
 salt, and well stirred; the whole is again put upon a woollen filter, and 
 allowed to drain. The extract remains as a thin pasty mass upon the 
 filter, and is ready for use. Various other proportions are used by manu- 
 facturers of this colour, but we have found the above to suit well for our 
 own use. 
 
 46. To make Sour Extract of Indigo. 
 
 We take this and the following from the Chemical News for 15th 
 January, 1875 : — “ To make what is generally called sour extract of indigo , 
 mix 5 lbs. of best Bengal indigo in 30 lbs. of strong oil of vitriol. Let it 
 stand five days; then put it in a tub, and add 40 gallons boiling water to 
 it ; then filter while hot through strong felt cloth. The filters are usually 
 made this way: — A frame like a table top, 8 yards long, 2 yards wide. 
 This frame is divided into four filters; pieces of wood across are put on 
 the top and made to fit the holes (the shape of bowls with holes perforated 
 in them); then the felt cloth is put on the top, and the liquid is put on 
 the filter and filtered through. The sediment at the top is used to colour 
 pottery moulds. That which is run through is put in a tub, and 40 lbs. of 
 common salt added ; digest for six hours, then put on the filter again for 
 four or five days. That which drains through runs away into the sewers. 
 That on the top of the filters is the extract. From these proportions the 
 extract should weigh 80 lbs. This is sour extract of indigo of commerce.” 
 
 47. To make Free Extract of Indigo. 
 
 “To make free extract of indigo, put 100 lbs. of the sour extract in a 
 tub, 12 gallons of water as well; neutralise the acid in the extract with 
 
PRELIMINARY PREPARATIONS. 
 
 349 
 
 strong soda-ash liquor until it is free from any sour taste ; then put on the 
 filter for six days. It should weigh 100 lbs. when it comes off. This is 
 free extract of indigo of commerce.” 
 
 48. TO MAKE CHEMIC. 
 
 Into a cask containing about 20 gallons of boiling water (the cask 
 JL should not be over three-thirds full) add 1 lb. of indigo made into sulphate 
 ^ or extract, then add by degrees ground whiting, stirring after each addi- 
 tion, and continue until the acid of the indigo is exactly neutralised, which 
 is generally known by the taste ceasing to be sour, as this is generally 
 used for dyeing greens on cotton with a vegetable yellow base ; if there be 
 more whiting added than will neutralise the acid, or too little to leave free 
 acid, the colours dyed with it will be faulty. The whole should stand for 
 eight or ten hours to settle after adding the whiting, when it is ready for 
 use. As a quantity of sediment collects at the bottom of the vessel, care 
 has to be taken to avoid disturbing this. Carbonate of soda may be used 
 instead of whiting, with the same precautions ; but this is not so good for 
 the colour, as soda salts remain in solution. 
 
 49. To prepare Safflower for Dyeing Cotton. 
 
 Take 1 lb. of safflower, and immerse in cold water until perfectly wet, 
 and the fibres all loose, then place it on a fine haircloth search, and pour 
 upon it clean cold water until the water passing through is not tinged 
 yellow. Dissolve 1 oz. of pearlash in 2 gallons water, and add the 
 washed safflower, stir and allow it to stand for five or six hours, after 
 which the whole is again put on the search, placed over a clean vessel to 
 retain all the liquid passing through which contains the dye. After pouring 
 a little clean water upon the exhausted safflower in the search to wash out 
 any dye, it is thrown away. 
 
 This dyeing liquor spoils by keeping, and should be used when newly 
 prepared. 
 
 50. To prepare Safflower for Dyeing Silk. 
 
 Into the liquid, as prepared in No. 49, is put 2 oz. by measure of 
 vitriol, well stirred, and a quantity of cotton is put into this and allowed 
 to steep for a few hours ; the colouring matter is imbibed by the cotton, 
 which is dyed a deep red. The cotton is now well washed in cold water 
 until all yellow colour is removed, and then wrought for fifteen minutes in 
 a vessel with cold water, having dissolved in it 1 oz. pearlash ; wring the 
 cotton from this, and the solution is ready for dyeing silk. 
 
 51. To make Oxalate and Muriate of Tin. 
 
 Dissolve 2 oz. of crystallised binoxalate of potash, then add 1 oz. of 
 crystals of tin, and stir till dissolved. 
 
350 
 
 DYEING RECEIPTS. 
 
 It is also prepared by adding to a pint of red spirits 2 oz. binoxalate 
 of potash, and stirring until it is dissolved; or the oxalate maybe dissolved 
 in water before adding it to the spirits. 
 
 52. To make Acetate of Alumina {Red Liquor). 
 
 In 1 gallon hot water dissolve 2 lbs. alum ; dissolve in a separate 
 vessel 2 lbs. acetate of lead (sugar-of-lead) in 1 gallon water ; in a third 
 vessel dissolve % lb. crystallised soda ; mix all the solutions together, and 
 stir well for some time, then allow to stand overnight ; decant the clear 
 solution, which is ready for use. 
 
 This mordant is obtained from drysalters under the name of red 
 liquor. 
 
 53. To test Water. 
 
 Take a small piece of white soap, and dissolve in alcohol, and let 
 the solution clear; if a little of this clear solution is added to distilled 
 water there is no precipitate, but if the water be hard it becomes milky ; 
 the hardness of the water may be known by the amount of milkiness or 
 precipitate given. 
 
 By taking a little of the water in a clean glass, and adding the follow- 
 ing tests, using a separate quantity of water for every test, the presence of 
 the following ingredients, which generally exist in water, will be ascer- 
 tained : — 
 
 Tests used. Indicate the presence of 
 
 If oxalate of ammonia gives a whiteness, Lime, free or combined. 
 
 If blue litmus is turned red, . . . Acids, uncombined. 
 
 If turmeric turns brown, . . . Alkalies and alkaline 
 
 earths. 
 
 If nitrate of silver gives white, and not (Muriatic acid, free or 
 cleared by the addition of nitric acid, \ combined. 
 
 If salts of barytes give white, not (Sulphuric acid and sul- 
 cleared by adding nitric acid, . . ( phates. 
 
 If lime-water gives milkiness, . . Carbonic acid. 
 
 If acetate of lead becomes brown or 
 
 black after standing, . . . Sulphides. 
 
 If chloride of calcium gives white, . Carbonated alkalies. 
 
 If phosphate of soda gives white after 
 long stirring, ..... Magnesia. 
 
 Carbonates of the earths, sulphates, muriates, and free acids make 
 water hard. 
 
 54. To make Lime-Water. 
 
 Into a barrel or other deep vessel, filled with cold water, add new- 
 slaked lime in the proportion of £ lb. to the gallon water, then stir well 
 and allow to settle ; the clear is what is used for dyeing. This should be 
 
PRELIMINARY PREPARATIONS. 
 
 351 
 
 made up just previous to using, as lime-water standing attracts carbonic 
 acid from the air, and forms an insoluble crust on the surface, which tends 
 to weaken the solution. 
 
 55. To make Cochineal Liquor, or Paste. 
 
 Put 8 oz. ground cochineal in a bottle, and add to it 8 oz. by 
 measure ammonia, and 8 oz. water; let the whole simmer together for a 
 few hours, when the liquor is ready for use. 
 
 56. To remove Mildew from Cotton. 
 
 Proceed with the stains by rubbing in soap or steeping in a little soda, 
 washing, and then steeping in bleaching liquor, same as No. 7 ; afterwards 
 pass through a sour, and wash. 
 
 57. To remove Indelible Ink Marks. 
 
 Steep the marking in a little chlorine water, or a weak solution of 
 bleaching liquor, for about half an hour, then wash in ammonia water, 
 which will remove the stain ; the goods should be washed from this in clean 
 water. 
 
 58. Another Method. 
 
 Spread the cloth with the ink mark over a basin filled with hot water, 
 then moisten the ink mark with the tincture of iodine, and immediately 
 after take a feather and moisten the parts stained by the iodine, then put 
 on it a solution of hyposulphite of soda, or caustic potash or soda ; when 
 the colour is removed, let the cloth dip into the hot water ; after a while 
 wash well and dry. 
 
 59. To detect Animal and Vegetable Fibres. 
 
 Treat the fabric with bichloride of tin heated to from 130° to 150° 
 Fah., when the cotton and linen become black, and wool and silk remain 
 unchanged. 
 
 60. To detect Mixed Fabrics of Cotton and Wool. 
 
 Dip a piece of the suspected cloth in bleaching liquor : after a little 
 the woollen turns yellow and the cotton white, and consequently may 
 be easily distinguished. 
 
 61. To detect Cotton in Linen. 
 
 The piece to be tested is boiled to remove all dressing, and then 
 dried ; a portion of the piece is put into common vitriol for about one 
 minute, it is then taken out, washed in water several times, and then in a 
 weak solution of soda or potash, and all gummy matter formed is removed 
 by gentle rubbing ; by this process the cotton is dissolved out and the 
 linen remains, or what portion of the cotton is not dissolved becomes 
 
352 
 
 DYEING RECEIPTS. 
 
 opaque white ; the linen is transparent, and is thus easily detected. By 
 comparing the portion of cloth immersed with a similar portion not tried, 
 the quantity of cotton present may easily be estimated. 
 
 62. Another method for detecting Cotton in Linen. 
 
 Take a small piece of the cloth, boil in water and dry; then take 
 three parts, by weight, of vitriol, and add to it two parts of crushed nitrate 
 of potash (nitre). The dry piece of cloth is put into this for six or seven 
 minutes, and then washed from this till there is no taste of acid, and dry 
 at a gentle heat; then put it into a mixture of ether and alcohol, which will 
 dissolve the cotton and not the linen. If the piece be weighed before 
 putting into the ether and alcohol, and after, the quantity of cotton in 
 the fabric may be thus ascertained. Or, dye the cloth with an alcoholic 
 solution of rosalic acid, then treat it with carbonate of soda in caustic 
 soda. The cotton remains undyed. 
 
 63. Cotton and Wool. 
 
 Take a small piece of the cloth and boil in caustic soda, No. 12, when 
 the wool will be dissolved and the cotton will remain. If the threads have 
 been previously counted, their relative mixture may be thus ascertained. 
 
 64. Cotton with Silk and Wool. 
 
 Put a piece of the cloth into chlorine water or bleaching liquor, No. 6. 
 The cotton is whitened by the liquor, and the silk and woollen become 
 yellow. These changes will be easily distinguished by the use of a small 
 pocket lens. 
 
 65. Cotton with Silk and Woollen. 
 
 Take a small piece and unravel the threads, and inflame them ; the 
 cotton burns away freely, with little or no black charcoal ; the woollen 
 and silk shrivel up, leave a black charcoal, and give a strong smell. 
 
 There are several other methods by dyeing— viz., by using a dye 
 that has an affinity for animal fibres without mordants— dipping the cloth 
 in this, the cotton remains white. Or, jute may be distinguished from 
 hemp or flax by giving a deep yellow with aniline sulphate, while the 
 others are not affected by this re -agent. 
 
 66. Softening. 
 
 Into a gallon of hot water dissolve | lb. of common soda, then add 
 ^ pint sweet oil, and stir well. A little of this is added to the washing 
 water for some colours, to soften the goods ; it is only applied to yarn. 
 
 67. To strip Royal Blue from Silk or Woollen. 
 
 For 8 lbs. stuff, either silk or woollen, take 2 lbs. copperas, 2 lbs. 
 bluestone, and 2 lbs. argol dissolved in water, and work the goods in it 
 
 warm. 
 
PRELIMINARY PREPARATIONS. 
 
 353 
 
 68. Strip Scarlet Cochineal Dye. 
 
 For each pound of cloth take half-ounce bichromate of potash and a 
 little vitriol, work in this a short time, and the colour is reduced to a 
 light fawn. 
 
 69. To make Soluble Prussian Blue for Domestic Use. 
 
 Take half-pound yellow prussiate of potash dissolved in water, add to 
 this half-pound, by measure, nitric acid, and then half-pound of copperas 
 in solution, stir well, and filter immediately, and wash the acid out, or 
 until the water passing through the filter is coloured blue ; dry at a steam 
 heat. 
 
 70. Another Method. 
 
 Take a solution of 4 oz. yellow prussiate of potash, and a solution of 
 4 oz. of copperas, to which has been added 1 oz. muriatic acid ; put half an 
 ounce of bleaching powder in 1 pint of water, and allow this to settle, and 
 put the clear solution into the solution of yellow prussiate; then mix 
 this with the copperas solution, stir well, and filter immediately; wash 
 until the liquor passing through ceases to taste of acid, the last portions 
 of the washing will be blue — the blue is dried at a steam heat, and is 
 ready for use. There are other methods, but these are simple and easy, 
 and they give good results. 
 
 71. To find the Quantity of Tannin in any Vegetable. 
 
 Make a solution of pure dry tartar emetic in 100 graduation measures 
 of water ; boil 50 grains of the substances to be tested, say sumach, in one 
 quart of water for fifteen minutes, and set aside to cool, add to this \ oz. 
 sal-ammoniac in solution. Then add by degrees the tartar emetic solution 
 until a precipitate ceases to be formed, then note the number of graduated 
 measures taken. As each grain of tartar emetic is equal to 2 grains of 
 tannin, and as every 10 graduation measures had 1 grain of tartar emetic in 
 solution, the calculation is easy ; say 50 graduations are taken, then as 
 10 : 2 : : 50 : 10 grains of tannin in the 50 grains of sumach, or 20 per cent. 
 
 71a. Testing Dyed Stuffs or Fibres. 
 
 A logwood dye, or the presence of logwood, is detected by putting 
 the dyed fibre into dilute sulphuric or muriatic acid, which removes the 
 colour or renders it brownish. If the acid used be neutralised with 
 ammonia, the liquor assumes a blue logwood colour ; and if the discharged 
 fabric be put into ammonia, it will give a slate colour. Supposing the 
 colour under test be a black, if it has been wholly dyed with logwood 
 the cloth becomes brown by the acid; but if it has had a blue bottom 
 the cloth after washing out the acid will remain blue. The same thing 
 applies to what are termed logwood blues; some of these have no blue 
 bottom, others have. 
 
 . Nitric acid should not be used for this testing, as it will remove indigo 
 blue and give an erroneous result. 
 
 z 
 
354 
 
 DYEING RECEIPTS. 
 
 Blue dyed with indigo is not altered by dipping in sour made with 
 sulphuric or muriatic acid, or by an alkaline ley. 
 
 Aniline blue is altered by caustic alkaline leys, becoming light grey ; 
 and a Prussian blue is completely removed by these re-agents, leaving a 
 buff or dun colour of peroxide of iron. 
 
 Colours dyed with oxide of iron give a blue by putting them into a 
 solution of yellow prussiate of potash, and iron colours are removed by 
 muriatic acid and water warmed ; by adding afterwards ammonia in excess 
 to the acid the iron is precipitated. 
 
 Yellows, boiled with soap. — If the dye is by fustic, it is removed ; if 
 by bark, the colour is browned, but not removed. Should the dye be 
 by chrome, putting it into an alkaline sulphide turns the dye black with a 
 yellow tint. 
 
 Reds by safflower are completely removed by an alkaline ley; but 
 the addition of an acid to the ley in excess’re stores the colour. 
 
 Reds by Brazil woods are mostly removed by a sour made with 
 vitriol. If the colour is washed in a solution of soap, it makes the solution 
 red ; if logwood has been mixed with the red dye, such as in crimsons, &c., 
 the soap liquor becomes of a lavender colour. 
 
 Greens being mixed dyes of yellow and blue, the kind of yellow used 
 is known by similar tests as given for yellows, and the kind of blue is 
 known by the same treatment as we have given for blue. Aniline greens 
 are known from their solubility in alcohol. 
 
 We take the following from the Chemical Society's Journal : — 
 
 “ A. — Blues. — Solution of citric acid or dilute hydrochloric acid is added. 
 (a.) Colour changes to red or orange. Logwood. 
 
 (6.) Colour does not change. 
 
 Another part is treated with calcium, chloride solution. 
 
 (a.) Colour remains unchanged. Prussian blue. 
 
 (6.) Colour changes. 
 
 Another part is treated with caustic soda. 
 
 (a.) The substance is decoloured. Aniline blue. 
 
 (6.) It remains unchanged. Indigo blue. 
 
 “B, — Yellows. — A portion is tested for ferric oxide by means of potas- 
 sium ferrocyanide ; another part is tested for picric acid by means 
 of potassium cyanide solution. The production of a blood-red colour 
 indicates picric acid. 
 
 If ,the colours are absent, another portion is treated with a boiling 
 soap solution (one part of soap in two hundred of water). 
 
 (a.) The colour changes to brown, but becomes yellow again with an 
 acid. Turmeric. 
 
 (b.) The colour becomes very dark. Fustic. 
 
 (c.) The colour unchanged. Weld , Persian berries , or quercitron. 
 
 Another portion is boiled with stannous chloride. 
 
PRELIMINARY PREPARATIONS. 
 
 355 
 
 (a.) The colour remains unchanged. Quercitron. 
 
 (b.) The colour changes to orange. Persian berries. 
 
 If annotta is the colouring matter present, the colour changes to 
 greenish blue on boiling in concentrated sulphuric acid. 
 
 “ C. — Reds. — The substance is treated with boiling soap solution. 
 
 (a.) The colour is totally discharged. Saffron carmine (safflower). 
 
 (b.) The colour is slightly discharged. Aniline red. 
 
 (c.) The colour changes to yellowish -red or yellow. Brazil-wood 
 or cochineal. 
 
 A part of the substance is treated with concentrated sulphuric acid. 
 (1.) A cherry-red colour is produced. Brazil-wood. 
 
 (2.) A yellowish-orange colour is produced. Cochineal. 
 
 (d.) The colour remains unchanged. Madder red. 
 
 This colour is not discharged by ammonium, chloride, or by a 
 mixture of equal parts of stannous chloride, hydrochloric acid, 
 and water. 
 
 “D. — Greens. — These colours may consist of a mixture of blues and 
 yellows, or of such substances as aniline green. 
 
 The substance is heated with alcohol of 95 per cent, in a water 
 bath. 
 
 (I.) The alcohol is coloured yellow, while the substance becomes more 
 and more blue. Indigo or Prussian blue is present ; the residue is 
 washed and tested for these blues, as already directed. The 
 alcoholic liquid is tested for yellows as above. 
 
 (II.) The alcohol is coloured green, while the substance becomes less 
 coloured. Aniline green , or a mixture of aniline blue with yellow is 
 present. 
 
 A part of the substance is boiled with dilute hydrochloric acid. 
 
 (a.) The liquid is coloured blue or lilac. Aniline green from methyl 
 iodide is present. 
 
 (6.) The substance is decolourised. Aniline green from aldehyde. 
 
 (c.) The substance is coloured blue, while the liquid becomes yellow 
 Aniline blue mixed with yellow. 
 
 “E. — Violets. — The substance is boiled in calcium chloride solution. 
 
 (a.) It is unchanged. Alcanna violet. 
 
 ( b .) It is coloured nankeen yellow. Madder violet. 
 
 ( c .) It is decolourised. Cochineal violet. 
 
 Another portion is boiled in eitric acid, the colour is brightened. 
 Aniline violet. 
 
 “To distinguish between the two aniline violets, a third part is boiled in 
 hydrochloric acid, which is diluted with three times its volume of water. 
 After washing it appears blue violet, if ordinary violet is the colour ; while, 
 if Hofmann’s violet is present, the substance appears greenish, and after 
 washing, light lilac or bluish.” 
 
COTTON DYEING. 
 
 GENERAL DIRECTIONS. 
 
 In the following receipts for cotton, the quantity of dye-stuffs given is for 
 dyeing 10 lbs. weight of goods, whether cloth or yarn ; so that the propor- 
 tions of the dye-drug may be easily calculated for any particular quantity. 
 When only small quantities of goods are to be dyed, such as gloves, 
 handkerchiefs, or a dress, the proportion of dye-stuffs may be increased with 
 good effect, as very small quantities cannot be done with the same economy. 
 
 The quantities given in these receipts, in connection with a pattern, 
 must be looked upon as a close approximation only, there being so many 
 circumstances to consider, that positive quantities cannot be given; for 
 instance, the quality of the fabric, the water, and the dye-drugs, are often so 
 varied as to require a difference of one-half more or less of the stuff to 
 produce the same effect. \ However, the amateur will find that in following 
 out any of the receipts, he will not fail to produce the colour required, if 
 not the exact tint. Thus, suppose it is wished to dye a brown of any 
 particular sort, say cinnamon brown, No. 77, by following the mode and 
 using the quantities given in the receipt a brown of that quality will be 
 produced; but should he wish to dye a brown of the exact tint and depth of 
 any pattern in the book, the quantities of stuff used may not produce that, 
 owing to the goods, stuff, or water, as already stated, not being the same 
 as were used for the pattern in the book. Nevertheless, by following the 
 instructions given in relation to the principle and reaction of the different 
 stuffs used for the dye, the amateur may be able to add such stuff as will 
 ultimately bring up the particular tint required. As, for example, logwood 
 gives the violet or blue tint, lima or peachwood the red or crimson tint, and 
 fustic or bark the yellow tint. 
 
 I have already referred to the preparation of cotton, silk, and woollen 
 for dyeing, which should be carefully attended to, otherwise the experi- 
 ments will not be successful. 
 
 It may be further remarked that, in giving receipts, the exact 
 quantity of water cannot be stated, as that will vary according to the 
 nature of the article to be dyed, shape of vessel, &c.; but in all cases the 
 quantity of water should be sufficient to allow the goods being put under 
 the liquor without being closely pressed. 
 
 For re-dyes, if the colour upon the goods be light, and that required 
 be dark, then it may not be necessary to remove it, but only to steep in 
 a little alkali, as soda, to remove grease or oil. In general, it is better to 
 clean the goods throughout, and for this purpose they should be put 
 through the bleaching process, No. 10. 
 
COTTON DYEING. 
 
 357 
 
 It may also be stated, as a general rule, that for all light shades of 
 colour, the cotton should be previously bleached, otherwise the colour 
 will not give satisfaction. The following will be a sort of guide: — For 
 all safflower colours, light yellows, sky blues, lavenders, nankeens, light 
 greens, very light drabs, &c., the goods should be bleached; for dark 
 drabs, browns, reds, slates, ambers, deep blues, black, dark greens, &c., 
 they need not be bleached. 
 
 All washing processes, except where otherwise mentioned, are in cold 
 water. 
 
 A question is often put in relation to a partially worn dress, what 
 colour will it dye? This depends much on the nature of the dye already 
 upon it. If it be one easily removed, it may dye any colour ; but if a per- 
 manent dye is on it, the dye required must not only be darker, but such as 
 the dye upon it can form a part, for instance, blue may be dyed black. 
 When the colour of an old dress has been faded in exposed parts, if the 
 colour cannot be removed entirely, it must be dyed a deep shade, to 
 hide the unequal parts caused by this circumstance. 
 
 DYEING. 
 
 72. Black. 
 
 Steep the goods in a decoction of 3 lbs. sumach, putting them in 
 while it is hot, and let them lie overnight ; wring out and work for ten 
 minutes through lime-water, No. 54, then work them for half an hour in a 
 solution of 2 lbs. copperas. They may either be washed from this or 
 wrought again through lime-water for ten minutes — the former gives the 
 preferable shade, but the goods must be well washed ; work them for half 
 an hour in a warm decoction of 3 lbs. logwood, adding half a pint chamber- 
 ley, urine, before entering the goods, then lift and raise with 2 oz. copperas 
 in solution ; work ten minutes, then wash and dry. 
 
 73. Jet Black. 
 
 The goods are proceeded with exactly as last ; but along with the 
 logwood is added 1 lb. fustic, and finished as above. 
 
358 
 
 DYEING RECEIPTS. 
 
 In both these blacks, if 3 pints iron liquor, No. 16, be used instead 
 of the copperas, or in part mixed with the copperas, it makes a richer 
 shade of black, but copperas is most generally used ; if mixed, use half 
 the quantity of each. 
 
 74. Blue Black.. 
 
 Dye the goods first a good shade of blue by the vat, No.. 39, and then 
 proceed exactly as No. 72 ; but should the blue be very deep, as is often 
 the case, then half the quantity of the materials given for No. 72 will 
 suffice. 
 
 75.. Spirit Brown.. 
 
 The goods are dyed first a spirit yellow, exactly as No. 104, and 
 washed ; they are then wrought for half an hour in a decoction of 2 lbs. 
 lima or peachwood and 1 lb. logwood ; lift the goods out the liquor and 
 add 3 oz. of alum in solution, and work fifteen minutes ; wash and dry. 
 By varying the proportions of logwood and limawood, a variety of shades 
 can be produced. 
 
 76. Mordant Brown. 
 
 Dye a yellow, the same as No. 106, then work for half an hour through 
 a decoction of 2 lbs. limawood and 8 oz. logwood, lift and raise with 2 oz. 
 alum in solution; work for fifteen minutes, and wash and dry. 
 
 This method is well adapted for cloth goods, is better than the spirits, 
 and more easily performed by the non-practical man. The spirit brown is 
 best for yarn. 
 
 77. Cinnamon Brown. 
 
 Dye a dark yellow, the same as No. 104, then work for twenty 
 minutes in 3| lbs. limawood and ^ lb. logwood ; then raise, by adding 
 2 oz. of alum in solution ; wash in cold water, and dry. 
 
COTTON DYEING. 
 
 78. UVANTERINE BROWN. 
 
 Dye a yellow, the same as No. 104, and then work for twenty minutes 
 in a decoction of 1 lb. limawood and 1 lb. fustic ; lift and raise, by adding 
 half pint red liquor, No. 52; work ten minutes in this; wash in cold 
 water, and dry. For light cloth the mordant yellow No. 106, is best for 
 these shades. 
 
 79. Fawn Brown. 
 
 Mix one part annotta liqour, No. 40, and one part boiling water ; 
 stir well, and work the goods in this for ten minutes ; wring out and wash 
 in two waters ; then work for twenty minutes in a decoction of 2 lbs 
 fustic and 1 lb. sumach ; lift and add 3 oz. copperas, in solution ; stir well, 
 and work for twenty minutes longer ; wash from this in two waters ; then 
 work for twenty minutes in a decoction of 8 oz. limawood, 8 oz. fustic, 
 and 4 oz. logwood ; lift and raise with 1 oz. alum ; work ten minutes ; 
 wring out and dry. 
 
 80; Bismarck Brown. 
 
 This is a rich brown, dyed with one of the coal-tar preparations, and 
 sold under the name of Bismarck brown; the tint is like No. 78. 
 
 Work in a hot decoction of \ lb. sumach for half an hour; wring out 
 and work for twenty minutes in a solution of 4^ oz. stannate of soda, and 
 wash from this. 
 
 In the dye-bath or boiler dissolve 4 oz. of the dye “ Bismarck brown,” 
 and work the goods in this for fifteen minutes, at a heat of 120° Fah., 
 about as hot as the hand can bear, wring out and dry. If the shade 
 required be redder than this preparation will give, add to the dye a little 
 alum or red liquor; and if required yellower, a little fustic added will 
 produce this, so that a considerable variety of tints may thus be obtained. 
 
 81. Catechu Brown. 
 
 Work the goods at a boiling heat for two hours, or steep for several 
 hours, if the liquor is allowed to cool, in 2 lbs. catechu, prepared as No. 
 41 ; wring out, and then work for half an hour in a hot solution of 6 oz. 
 bichromate of potash (chrome); wash from this in hot water. If a little 
 soap be added to the washing water the colour is improved. 
 
360 
 
 DYEING RECEIPTS. 
 
 Any depth of shade of brown may be dyed by repeating the operation, 
 or lighter shades may be got by using a smaller portion of materials. 
 
 82. Catechu Chocolates. 
 
 Dye a brown, as No. 81, then work fifteen minutes in a decoction of 
 lb. logwood ; lift, and add 3 oz. alum, in solution ; work ten minutes 
 longer ; wash out and dry. 
 
 By this process a great variety of browns and chocolates may be pro- 
 duced, both by using different quantities of logwood, and by different 
 depths of brown before the logwood is applied. 
 
 83. Chocolate or French Brown. 
 
 Dye a yellow, as No. 104, then work for half an hour in a decoction of 
 3 lbs. logwood ; lift, and raise with half a pint of red liquor, No. 52, and 
 work ten minutes longer ; wash and dry. 
 
 Another shade of deeper chocolate will be obtained by adding 1 lb. 
 fustic with the logwood ; for cloth dye the yellow as No. 106. 
 
 84. Catechu Fawns. 
 
 Work the goods fifteen minutes in hot water, to which has been added 
 2 pints of the catechu, No. 41 ; wring from this, and work fifteen minutes 
 in hot water, in which has been dissolved 1 oz. of bichromate of potash ; 
 wash from this, and dry. 
 
 85. Catechu Fawns — Another Method. 
 
 Work in the solution of catechu the same as No. 81 ; wring out, and 
 
COTTON DYEING. 
 
 361 
 
 then work for fifteen minutes in warm water, to which has been added 
 2 oz. acetate of lead previously dissolved ; wash in cold water and dry. 
 
 86. Catechu Fawns — Another Method. 
 
 Work for fifteen minutes in warm water, to which has been added 
 4 pints of catechu, No. 41 ; lift, and add 2 oz. copperas in solution, and 
 work for other fifteen minutes. Wash from this in one tub water, and 
 finish through warm water, in which as much soap has been dissolved as 
 will raise a lather, and dry out. A great variety of drabs can be dyed by 
 varying the proportions of these matters. 
 
 87. Safflower Pink. 
 
 Two lbs. of safflower prepared as No. 49, adding as much water with 
 the safflower liquor as will be sufficient for the quantity of goods ; work 
 in this for five minutes, and lift out, taking care not to lose any of the 
 liquor, then add about 1 gill of sulphuric acid. The liquor should taste 
 decidedly acid. Enter the goods in this, and work an hour; wring out, 
 and wash in three separate waters ; but in the last water there is to be 
 put as much cream of tartar in solution as to be perceptible to the taste ; 
 wring from this, and dry in the air, or in a very dry heat, carefully avoiding 
 steam or the sun’s rays, which affect the colour. The cream of tartar 
 should be dissolved in boiling water before adding. 
 
 88. Rose Colour. 
 
 Prepare 4 lbs. of safflower as No. 49, then proceed to dye exactly as 
 No. 87 ; the vitriol to be added to the safflower in sufficient quantity to 
 give the liquor a sour taste ; work an hour, or until a drop of the liquor 
 
362 
 
 DYEING RECEIPTS. 
 
 upon the point of the finger, held between you and the light, has no 
 reddish tint ; wring out, wash, and finish as above. 
 
 89. Safflower Crimson. 
 
 Prepare 7 lbs. safflower as No. 49, and then proceed as No. 87 ; it 
 may be requisite to lift once or twice during working, and add each time 
 one glass of vitriol ; the acid taste should always prevail. This colour 
 requires to be wrought for several hours before all the red colouring 
 matter of the safflower is taken up. It also requires an extra tub of water 
 in washing. 
 
 90. Safflower Red. 
 
 Into a tub of warm water add two imperial pints of annotta, No. 40, 
 and work the goods through this for twenty minutes ; wring out, and then 
 proceed to dye with 6 lbs. of safflower, in every way as No. 88, and finish 
 in the same manner. 
 
 91. Safflower Scarlet. 
 
 Dye a deep orange with the annotta solution, No. 40, about one 
 measure water to one measure annotta ; wring out, wash from this, and 
 then work in 7 lbs. of safflower, No. 49, and proceed exactly as in No. 88 
 for crimson, and finish in the same manner. 
 
 The annotta liquor used for this should not be thrown away, as it 
 will serve again either for this or other light shades. 
 
 92. Aniline Pink. 
 
 This colouring matter is sold under the designation of saffronine or 
 saffronine crystals. About half an ounce of the dye is dissolved in the dye 
 bath or boiler, which should be kept at a heat of about 100° Fah. ; the 
 goods, after being well bleached and washed from any remaining salts, are 
 wrought in this solution for fifteen or twenty minutes, wrung out and 
 dried. For darker or lighter shades of pink more or less of the saffronine 
 is used. 
 
 93. Common Red. 
 
 Boil or scald, No. 42, 3 lbs. sumach ; put the goods into this as soon 
 as possible after the grounds settle or the liquor is decanted, and let them 
 
COTTON DYEING. 
 
 363 
 
 steep till the liquor is cold, say overnight ; wring out, and work for an 
 hour in red spirits diluted to from 2° to 2^° Twaddell’s hydrometer, or 
 about 1 gill spirits, No. 29, to each gallon water ; wring out, and wash 
 well, and make a decoction, No. 42, of 3 lbs. limawood and 1 lb. fustic ; 
 work the goods in this for half an hour at a heat that the hand may be 
 held in without pain, lift up and raise by adding 1 gill red spirits, No. 29 ; 
 return the goods and work fifteen minutes longer wash out and dry. 
 
 94. Bakwood Red. 
 
 Boil 2 lbs. sumach and decant the clear, add a wine-glassful of 
 vitriol, and steep the goods in this decoction for at least six hours ; wring 
 out and work in spirits, No. 31, diluted to 2^° Twaddell, for an hour ; 
 wring out and wash, then pass through a tub of warm water ; put 10 lbs. 
 of barwood into a boiler with water, and bring it near to the boil, into 
 which the goods are entered and wrought amongst the wood grains for 
 about three-quarters of an hour; lift out, wash, wring, and dry. 
 Deeper shades may be dyed by using greater quantities of stuffs in each 
 operation. 
 
 Instead of the spirits some prefer stannate of soda, as giving a softer 
 tint ; the operations otherwise are the same ; only use no vitriol with the 
 sumach, of which take 1| lb. instead of 2 lbs. 
 
 95. Aniline Red. 
 
 Steep the goods overnight in a decoction of 2 lbs. of sumach, putting 
 them in while the liquor is hot; ; wring out and work for half an hour in 
 red spirits (No. 29), at 3° Twad., and wash from this until no taste of 
 the spirits is perceptible in the goods. To the dye-bath put in 2 lbs. of 
 red paste ; work the goods in this for fifteen minutes, at a heat of 120° ; 
 wring out and dry. There are in the meantime three different shades of 
 colour sold and known as red paste, marked Nos. 1, 2, and 3. No. 1 
 gives a yellow-red, approaching to a scarlet. No. 2, a rich red, allied to 
 Turkey. No. 3 has a blue tint, like that from barwood. These reds have 
 the advantage over ordinary reds by the red woods, as they stand washing 
 in soap solutions, nor do they turn purplish by alkalies like the dyes from 
 wood. 
 
364 
 
 DYEING RECEIPTS. 
 
 96. Common Crimson. 
 
 Three lbs. sumach are boiled or scalded, No. 42, and the goods steeped 
 in it overnight, and then spirited at 2 Q T wad dell, same as No. 93 ; wash and 
 work through a decoction of 3 lbs. limawood and 1 lb. logwood for thirty- 
 minutes, then raise with a gill red spirits, No. 29 ; work for fifteen minutes 
 more, wash out and finish. 
 
 By using only limawood without logwood a beautiful red crimson is 
 obtained, and by varying the proportions and quantities of the two woods 
 a great variety of tints may be dyed by the same proportion of sumach and 
 spirits. Although limawood is here, and in the other receipts named, it 
 embraces what are termed Brazil-woods. 
 
 97. Magenta. 
 
 Work for half an hour in a hot decoction of l\ lb. of sumach ; wring 
 out and work for twenty minutes in a solution of 12 oz. of stannate of soda, 
 and wring out; dissolve 1 oz. of magenta crystals in boiling water; add 
 this to the dye-bath, with the proper quantity of water to work the goods ; 
 work in this for 15 minutes at a heat of 120° Fah. ; wring out and dry. 
 
 98. Light Straw. 
 
 To a tub of cold water add 4 oz. of acetate of lead (sugar of lead), 
 previously dissolved, work the goods through this for fifteen minutes, and 
 wring out; into another tub of water add 2 oz. bichromate of potash 
 (chrome), work the goods through this ten minutes, wring out, and pass 
 again through the lead solution for ten minutes, wash and dry. 
 
 
 99. Leghorn. 
 
 Proceed and finish exactly as No. 98, but along with the chrome add 
 ^ pint annotta liquor, No. 40. 
 
 Different depths and tints may be obtained by using more or less of 
 these stuffs, without varying the mode of working. 
 
 100. Lemon Yellow. 
 
 Into a tub of cold water put 1 lb. of acetate of lead (sugar of lead), 
 
COTTON DYEING. 
 
 365 
 
 previously dissolved ; work the goods in this for fifteen minutes, and wring 
 out; into another tub of cold water put 6 oz. bichromate of potash in 
 solution ; work the goods for fifteen minutes through this, and wring out ; 
 then put back, and work ten minutes in the lead solution ; wring out, 
 wash, and dry. 
 
 101. Chrome Yellow. 
 
 Proceed and finish exactly as No. 100, but using twice the quantity of 
 stuff ; or with the same quantity of stuff passing the goods twice through 
 the chrome and lead, and finishing out the lead as described ; by these 
 means any depth of yellow may be dyed with lead and chrome. 
 
 102. Chrome Amber. 
 
 To a tub of cold water add 1 lb. acetate of lead and 1 lb. nitrate of 
 lead in solution ; work the goods in this for half an hour and wring out, 
 then in a tub of warm water add 12 oz. chrome, and work the goods from 
 the lead through this for fifteen minutes ; expose to the air for half an 
 hour, then pass again through the lead and chrome, working the same 
 time in each as before, and allow an hour’s exposure out the chrome the 
 second time ; then pass through the lead ; wring out, and wash and dry. 
 A third dip may be given, if not deep enough, observing the same rules. 
 
 103. Another Method for Dark Yellows. 
 
 Into a tub of water add 1 lb. acetate of lead, and to this add gradually 
 caustic potash or soda, Nos. 11 and 12, until the precipitate formed be 
 re-dissolved, taking care not to add more caustic alkali than is required 
 for this solution. Work the goods through this for half an hour ; 
 
366 
 
 DYEING RECEIPTS. 
 
 wring out, then dissolve 8 oz. chrome in another tub of water, and work 
 the goods in this for fifteen minutes; wring out, and wash and dry. 2 or 
 3 oz. of sulphate of zinc may be added to the chrome solution with good 
 effect. If a red deep amber be required, add to the chrome solution 
 j pint muriatic acid. 
 
 104. Spirit Yellow. 
 
 Steep or lay the goods in a decoction of 3 lbs. sumach, as No. 93 ; 
 lift and wring out, and then work in the spirit, either No. 29 or 30, diluted 
 to 2° Twaddell, for half an hour ; then wash out. Into a coarse canvas 
 bag put 3 lbs. quercitron bark, and put this into a copper boiler with as 
 much water as will allow the goods to be wrought easily, boil for 
 half an hour ; remove the bag with the bark, and work the goods in the 
 decoction for fifteen minutes ; lift. and add 1 pint of yellow spirits, No. 30, 
 or red spirits, No. 29; work in this for half an hour; wash out till no taste 
 of spirits is felt, and dry. An iron vessel will not do for this operation. 
 
 105. Light Spirit Yellow. 
 
 Work the goods through the spirits, Nos. 29 or 30, made down to 2° 
 Twaddell, for half an hour, without being previously sumached ; then wash 
 out and dye with the bark, prepared as No. 104; proceed in the same 
 manner, by adding the spirits, washing, and finishing. 
 
 106. Bark Yellow with Mordant. 
 
 Work the goods for ten minutes in red liquor, No. 52, made to 8° 
 Twaddell ; wring out and wash in a tub with hot water ; then work 
 through a decoction of 2 lbs. bark, No. 42, for half an hour ; lift and add 
 a pint of red liquor, No. 52 ; work fifteen minutes, and wash and dry. 
 
 107. Chrome Orange. 
 
 Boil 2 lbs. of brown acetate of lead and 1 lb. of litharge in 3 gallons 
 of water for an hour ; take two -thirds of the clear solution in a tub of 
 cold water, and work the goods in this for fifteen minutes ; wring out, and 
 work through lime-water, No. 54, for ten minutes ; wring out, and put 
 back into the lead tub ; work other fifteen minutes, wring out and 
 give another tub of lime-water ; then back again to the lead, adding 
 the remaining solution of lead to it ; after fifteen minutes’ working, 
 wring out, and work ten minutes through a tub of water with 1 lb. of 
 chrome dissolved in it ; wring out, and pass again through the lead and 
 chrome as before; then work in lime-water heated from 200° to 206° Fah., 
 when the orange colour is obtained ; then wash through a tub of hot water, 
 into which is put a little softening, No. 66 ; wring and dry. 
 
COTTON DYEING. 
 
 367 
 
 108. Another Method for Chrome Orange. 
 
 Take 2 lbs. of sugar of lead, dissolved in water, and add to this lime- 
 water till the lead that is precipitated is re-dissolved ; then work the goods in 
 this for twenty minutes ; wring out and work for ten minutes in a solution 
 of 1 lb. of chrome ; wring out and pass twice through the lead and chrome 
 in the same way ; then raise by working in hot lime-water, as No. 107; 
 wash in hot water with softening, and dry. 
 
 Where heavy goods are dyed, caustic soda or potash in solution is used 
 instead of lime for raising the orange. 
 
 109. Annotta Orange. 
 
 Heat the annotta solution, No. 40, to working heat — about 120° Fah. ; 
 work the goods in this for twenty minutes ; wring tightly out, in order not 
 to lose much stuff ; wash in a couple of waters, and dry. 
 
 If this colour is passed through water made to taste sour by an acid, 
 a very red orange, bordering on scarlet, is produced; but the colour is very 
 fugitive, not that it is easily removed, but changes easily by acid or alka- 
 line substances, and by exposure to light. 
 
 110. Sky Blue or Prussian Blue. 
 
 For light blues the goods should be bleached Nos. 7 and 10 ; then to a 
 tub of cold water, sufficiently large to work the goods in easily, add ^ pint 
 nitrate of iron, No. 15, and work in this for twenty minutes ; wring out, 
 and pass through one tub of clean water. Into another tub of cold water 
 add 4 oz. yellow prussiate of potash, in solution, and about a wine-glassful 
 of vitriol ; work the goods in this for fifteen minutes ; wring out, and wash 
 through cold water, in which is dissolved 1 oz. of alum ; wring out and dry. 
 
 To dye lighter or darker shades of shy blue, use less or more of the 
 iron and yellow prussiate; or should the shade be too light after passing 
 through the operations described, by repeating the operations through the 
 same tubs, only adding an ounce more yellow prussiate, the shade will be 
 deepened nearly double. There are a variety of blues with peculiar tints, 
 such as a reddish or purple hue, or greenish tint, which were popular for a 
 time under certain designations, such as mazarine blue, Waterloo blue, 
 
368 
 
 DYEING RECEIPTS. 
 
 Napoleon blue, &c. The mode of dyeing these remain, but they have 
 been re-christened with some more popular names. Waterloo blue was 
 simply a deep Prussian blue. The Napoleon is the same, having a reddish 
 tint. 
 
 111. Napoleon Blue. 
 
 The cotton should be bleached before dyeing. Into a tub of cold 
 water add 1 imperial pint of nitrate of iron, No. 15, and 2 gills muriatic acid, 
 then add 3 oz. crystals of tin, No. 26, or a pint of double muriate, No. 34; 
 stir well, and immediately enter the goods, and work for thirty minutes ; 
 wring out, and put directly into the prussiate tub, made up with water, 
 into which is put a solution of 12 oz. yellow prussiate and one wine-glassful 
 of muriatic acid ; work in this for fifteen minutes, then wash out in clean 
 water in which is dissolved 2 oz. alum. If a deeper shade of blue is 
 required than these quantities will give, the goods are washed from the 
 prussiate tub in water, without alum, and passed again through the iron 
 and prussiate, and then washed out, as above, with alum in the last water. 
 
 112. Royal Blue. 
 
 This is dyed in the same manner as the above; but the liquors are 
 stronger — using 2 pints iron, 2 gills muriatic acid, and 4 oz. tin crystals, No. 
 26. The prussiate tub is made up by dissolving in it 1 lb. yellow prussiate 
 of potash, and adding one wine-glassful of sulphuric acid and one glassful 
 muriatic acid. All the other operations are the same as No. 111. If not 
 sufficiently dark with putting once through, repeat. 
 
 113. China Blue. 
 
 This is one of the coal-tar blues sold under the above name. Bleach 
 the goods well, then work them for fifteen minutes in a solution of 
 
COTTON DYEING. 
 
 369 
 
 £ lb of alum, at a heat of 100° Fah.; lift the goods out, and add to the 
 solution oz. of china blue crystals, previously dissolved in boiling water; 
 re-enter the goods and work for twenty minutes; wring out and dry. 
 Deeper or lighter shades can be given by increasing or lessening the 
 quantity of the dye. 
 
 114. Opal or Spirit Blue. 
 
 The goods are worked for half an hour in a hot solution of 1 lb. of oil 
 soap; lifted and wrung out, and then worked for fifteen minutes in a hot 
 solution of 1 lb. of alum and wrung again. 
 
 There is then dissolved f oz. of the blue dye in 3 pints of methylated 
 spirits kept hot until the whole is dissolved. A little of this is added to 
 the dye-boiler while the water is cold, and the goods are entered and 
 wrought in this ; the heat of the boiler is gradually raised until it boils ; 
 during this interval the goods are lifted from time to time, adding at each 
 time more of the dyeing liquor ; the whole should be added by the time 
 the solution begins to boil. It is kept at the boiling point, and the goods 
 wrought in it for fifteen minutes ; they are then removed and washed in 
 cold water and dried. This blue is generally required of a greenish tint 
 as compared with china blue. This is obtained by longer boiling and 
 exposure to the air after. This is the fastest of the coal-tar colour blues 
 upon cotton. 
 
 115. Logwood Blue. 
 
 Dye first a light blue with the vat, No. 39, then allow to lie in a hot 
 decoction of 2 lbs. sumach for several hours, and then keep working for 
 fifteen minutes through water to which has been added 1 pint acetate of 
 alumina (red liquor), and 1 pint acetate of iron (iron liquor); wash well 
 from this in hot water, then work twenty minutes in a decoction of 2 lbs. 
 logwood; lift, and raise with | pint of red liquor; work ten minutes longer ; 
 wash and dry. 
 
 116. Indigo Vat Blue. 
 
 If the goods be yarn they are wrought for fifteen minutes in the vat, 
 No. 39, wrung out, the wringings put back into the vat, and the goods 
 exposed for an hour to the air ; if the blue be deep enough in colour, 
 they are washed and dried ; if not dark enough, they are passed again 
 through the vat in the same way, repeating as often as the depth of shade 
 requires. When the colour is dark, the goods are passed through a tub of 
 water with as much sulphuric acid, perfectly free from nitric acid, in it as 
 makes it taste perceptibly sour, washed well and dried. For very light 
 shades the yarn is bleached, but for ordinary and deep shades it is 
 unbleached. Cloth dyed vat blue is generally stretched upon a frame, and 
 then immersed into the vat with the frame, or made to pass over rollers 
 under the liquor, to obtain an equality of dye over all the piece. 
 
 Care must be taken, whether in dyeing yarn or cloth in the blue vat, 
 that the sediment or sludge at the bottom be not disturbed by agitation ; 
 for if the goods come into contact with it, the colour will be destroyed by 
 
 2 A 
 
370 
 
 DYEING RECEIPTS. 
 
 being dirty and grey looking. When the dyeing in a vat is finished for the 
 day, the vat is stirred up and allowed to settle all night. A vat should 
 never be used until several hours after stirring (see page 268). 
 
 117. Chrome Green. 
 
 Dye a blue by the blue vat, No. 39, about twice the depth of the sky- 
 blue pattern, No. 110 ; then work it twenty minutes through a solution of 
 1 lb. acetate of lead, prepared as No. 103, with soda or potash ; wring out, 
 and work for fifteen minutes in a tub with 6 oz. of chrome in it, then wash 
 out and dry. 
 
 It will be observed that this kind of green is obtained first by dyeing 
 a blue and then a yellow on the top of the blue ; by the depth of either every 
 variety of shade canlbe produced. The principal difficulty is, when a par- 
 ticular shade is required, to get the proper depth of ‘blue ; for after the 
 yellow has been dyed upon it, blue cannot be dyed on the top of the yellow 
 by the vat. This difficulty can only be got over by experience. 
 
 The mode of dyeing yellow, No. 100, may be adopted upon the blue, 
 but there is a great tendency to an unequal colour by this method. 
 
 This pattern is not produced by chrome, but is of a similar tint. 
 Chrome green is seldom dyed upon cloth, but is the principal kind of green 
 upon yarn. 
 
 118. Bark Green on Yarn. 
 
 The goods are dyed a blue in the vat, No 39, according to the shade 
 required, and when washed from this vat are wrought for fifteen minutes 
 in red liquor, at 78 Twaddell; they are wrung out, and put through a tub 
 of hot water, then worked for half an hour in a decoction of 3 lbs. bark, 
 and raised by adding £ pint of red liquor, and working fifteen minutes, 
 then washed and dried. 
 
 119. Fustic Green on Yarn. 
 
 Dye a vat blue, in No. 39 ; wash and wring, and then pass through the 
 acetate of alumina, No. 52, at 6° Twaddell ; wash through a tub of hot 
 water, and then work for twenty minutes in a decoction of 4 lbs. fustic ; lift 
 and raise with 2 oz. alum in solution ; work fifteen minutes, wash, and dry. 
 
 120. Bark or Chemic Green on Cloth. 
 
 The goods after being cleaned, not bleached, are wrought for ten 
 minutes in red liquor at 7? Twaddell, wrung out, and passed through a 
 
COTTON DYEING. 
 
 371 
 
 tub of hot water, and then wrought for half an hour in a decoction of 3 lbs. 
 bark, lifted and raised with £ pint red liquor, and wrought ten minutes 
 longer, then lifted and drained or wrung out. Into a tub of cold water 
 put 5 gallons of chemic, No. 47 or 48 ; the yellow cloth is worked in 
 this for twenty minutes, wrung out and dried. Of course, any depth of 
 shade may be made in this way by varying the quantity of stuff used. 
 
 121. Fustic Green on Cloth. 
 
 Work the goods in acetate of alumina, No. 52, at 6° Twad., and dry 
 from this in a stove or hot chamber ; then wet out in hot water, and work 
 for twenty minutes through a decoction of 3 lbs. fustic ; lift and raise with 
 2 oz. alum, in solution ; work fifteen minutes ; wring out, and then work 
 in the chemic prepared as last ; wring out and dry. 
 
 122. Green with Prussian Blue. 
 
 Dye a good Prussian blue same way as sky, No. 110, according to 
 the depth of green required ; and then work ten minutes in acetate of 
 alumina, red liquor, at 6° Twad.; wash in warm water, and work for half 
 an hour in a decoction of 3 lbs. fustic ; lift and raise with 2 oz. alum, in 
 solution ; work ten minutes longer ; wash and dry. 
 
 Bark may be substituted for fustic in this green. If so, the bark 
 should not be wrought very warm ; and thus a finer tint is obtainable. 
 
 123. Sage Green. 
 
 Dye a Prussian blue same as sky, No. 110, and work ten minutes in 
 a solution of 2 lbs. alum ; wring out, and work fifteen minutes in a 
 decoction of 1 lb. fustic ; lift, and add a pint of the alum solution formerly 
 used ; work ten minutes, and then wash and dry. 
 
 
 
 
 
 
 
 
 
 . 
 
 
 wmmm 
 
 
372 
 
 DYEING RECEIPTS. 
 
 124. Olive or Bottle Green. 
 
 Dye a good shade of Prussian blue, No. 110 ; then mordant by work- 
 ing ten minutes in acetate of alumina (red liquor), at 7° Twad.; wring out 
 and wash in hot water ; work for half an hour in a decoction of 3 lbs. 
 fustic and 1 lb. sumach ; then add \ pint iron liquor, No. 16, and work 
 fifteen minutes ; then wash in a tub of water having 2 oz. alum dissolved 
 in it, and dry. 
 
 125. Olive or Bottle Green— tAnother Method. 
 
 Work the goods in red liquor at 7° Twad., wash in warm water, and 
 work half an hour in a decoction of 3 lbs. bark and 1 lb. sumach ; lift, and 
 add pint iron liquor, No. 16 ; work other fifteen minutes ; wring out, and 
 then work fifteen minutes in the chemic prepared as in No. 120 ; wring out 
 of this and dry. 
 
 126. Deep Olive Green. 
 
 Dye a Prussian blue, No. 110, then work for ten minutes in red liquor 
 at 6° Twad.; wash in hot water, and work in a decoction of 3 lbs. bark 
 and 1 lb. logwood ; lift, and raise with \ pint of red liquor, and work ten 
 minutes ; wash from this and dry. 
 
 A great variety of shades of green may be obtained by varying the 
 proportions of bark and logwood. Fustic may also be used instead of 
 bark. 
 
 If the goods be yarn, a light vat blue may be dyed instead of the 
 Prussian blue, and proceeded afterwards in the same manner as above. 
 
 127. Aniline Green. 
 
 Work in a hot decoction of 2 lbs. sumach for twenty minutes; wring 
 out, and work for fifteen minutes in a solution of 12 oz. of stannate of soda, 
 and wring out. 
 
 Dissolve 3 oz. of aniline green crystals and 5 oz. of alum in the dye-bath, 
 work in this for twenty minutes, at a heat of 100° Fah., lift up, and add to 
 the bath 1^ pint of a strong decoction of fustic ; work in this fifteen minutes ; 
 wring out and dry. If the green required be more of a blue colour, use 
 less fustic ; if more yellow, use more fustic. 
 
COTTON DYEING. 
 
 373 
 
 128. Lavender Puce or Lilac. 
 
 Work for an hour in red spirits, No. 29, made down to 2° Twad.; 
 wring out and wash, then work half an hour in a decoction of 3 lbs. of 
 logwood, at working temperature, about 120° Fah.; lift up r and add 1 
 gill red spirits, No. 29 ; work for twenty minutes ; wash from this and 
 dry. One half pint red liquor, or 2 oz. alum, may be added to the log- 
 wood as raising, instead of red spirits. 
 
 129. Another Method. 
 
 Work the goods for fifteen minutes in red liquor, at 7- Q Twad.; wring 
 out and wash in warm water ; then work half an hour in a decoction of 
 2 lbs. of logwood, at working heat ; lift and raise with ^ pint red liquor, 
 or 2 oz. alum ; work ten minutes in this, and wash in a tub of lukewarm 
 water ; wring out and dry. 
 
 130. Light Purple or Adelaide. 
 
 The goods are laid in a decoction of 2 lbs. sumach, as No. 72, wrung 
 out, and wrought half an hour through the spirit plumb liquor, No. 36 ; 
 wrung out, and washed in clean cold water till no taste of acid is felt on 
 the goods, then dried. 
 
 When working with the spirit plumb liquor, it is best to take the 
 plumb liquor into a tub or separate vessel, and work the goods in this, 
 returning the liquor afterwards to the plumb tub. 
 
 131. Another Method and Deeper Shade. 
 
 The goods are laid in 2 lbs. sumach, as No. 72, wrung out, and 
 wrought for twenty minutes in red spirits, No. 29, at 2° Twad.; washed well 
 
374 
 
 DYEING RECEIPTS. 
 
 from this, then worked in the spirit plumb, No. 36, in the same manner 
 as No. 130 ; washed out till no taste of acid is on the goods, and dried. 
 
 132. Ordinary Purple. 
 
 Boil two pounds of sumach, and treat the goods in the same way 
 as No. 72 ; work in red spirits at 2° Twad. for an hour, and wash in cold 
 water ; then work for half an hour in a decoction of 3 lbs. of logwood, at 
 working heat ; then lift, and add 1 gill of spirits, No. 29, and work for ten 
 minutes more ; wash in cold water and dry. 
 
 A variety of purple shades may be dyed by this process by slightly 
 varying the proportions of the stuffs. If a browner tint is required, give a 
 little more sumach ; if a bluer tint, less sumach, and increase the logwood, 
 and raise with ^ pint red liquor, or 2 oz. alum, instead of red spirits. 
 
 133. Lavender or Peach. 
 
 Work the goods for twenty minutes through the spirit plumb liquor. 
 No. 36, without any previous preparation ; wring out, and wash in clean 
 cold water till no taste of acid is felt, and dry. 
 
 134. Logwood Puce. 
 
 Dye the goods a good shade of Prussian blue, No. 110, then work for 
 fifteen minutes in a decoction of 1 lb. of logwood, at working temperature ; 
 lift up, and add 4 oz. alum ; work ten minutes, and then wash in cold 
 water and dry. 
 
 135. Another Method. 
 
 Dye a sky blue as No. 110, then to a tub of warm water add one 
 gallon alum plumb liquor, No. 37, and work in this fifteen minutes ; wring 
 out and dry. 
 
 136. Light Lavender. 
 
 To a tub of warm water add two gallons of alum plumb liquor, 
 No. 37, and work the goods in this for fifteen minutes ; wring out and 
 dry. If a blue tint is required, add with the plumb ^ pint of chemic, 
 No. 48. 
 
COTTON DYEING. 
 
 375 
 
 137. Aniline Purple. 
 
 Work for half an hour in a hot decoction of 1 lb. of sumach ; wring 
 out, and work for twenty minutes in a solution of 8 oz. of stannate of soda, 
 and wring out. 
 
 Into the dye-bath put f oz. of what is known in the market as 
 Schumacher, No. 8, with one gill red liquor-; work in this for about 
 twenty minutes at a heat of 1208 ; wring out and dry. If a bluer shade is 
 required, work the bath at 150°, and add a little more red liquor. 
 
 138. Mauve. 
 
 Work for half an hour in a hot decoction of 1^ lb. of sumach ; wring 
 out, and work in a solution of 12 oz. of stannate of soda. 
 
 Into the bath put 1^ oz. of mauve dye, with fully one quart of red 
 liquor; work in, this for fifteen minutes at a heat of 120° Fah.; wring 
 out and dry. 
 
 139. Aniline Lavender. 
 
 The cotton for this colour to be well bleached. Into the d'ye-bath 
 put one pint of red liquor, and work in this for fifteen minutes at a heat 
 of 10O Q Fah. ; lift up, and add ^ oz. lavender dye ; work in this for 
 twenty minutes ; wring out and dry. A great variety of shades of lavender 
 can te dyed by varying the quantity of the dye ; besides, there are a 
 great variety of different colouring matters in the market giving lavenders 
 from a reddish-blue to a bluish-pink, which the dyer may select as 
 required. 
 
 140. French, White.. 
 
 ( For Pattern , see Safflower Lavender , No. 141.)" 
 
 To a tub of hot water add one pint of alum plumb, No. 37, and half a 
 pint of chemic, No. 48 ; work in this fifteen minutes ; wring out and dry. 
 
 141. Safflower Lavender. 
 
 Dye the goods a sky blue, No. 110, then dye a safflower pink on the 
 top of the blue, No. 87, with 1 lb. safflower; but in dyeing the pink the 
 sulphuric acid must be added to the safflower liquor previous to the blue 
 being entered into it, otherwise the alkali of the safflower will destroy 
 the blue. 
 
 We need hardly add that different depths of colour, and different 
 hues, will be obtained by varying the shade of blue and the quantity of 
 safflower. Deep blue and little safflower gives a lilac or puce ; while 
 a light blue, such as pattern No. 110, with 4 lbs. safflower, will give a 
 
376 
 
 DYEING RECEIPTS. 
 
 peach colour; and a blue one-half the depth of No. 110, and pink with 
 j lb. of safflower, will give a French white. 
 
 142, Safflower Lavender — Another Method. 
 
 Dye a pink with 2 lbs. of safflower, No. 87, then proceed and dye a 
 sky blue over this, No. 110, and finish exactly as described for sky blue. 
 
 Of course, the remarks made at No. 141, in reference to different 
 shades, apply equally to this method ; but more safflower is required by 
 this method than the other. 
 
 143. Iron Buff or Nankeen. 
 
 Take 2 lbs. of sulphate of iron (copperas), and dissolve in varm 
 water, and then add the requisite quantity of water for working the 
 goods ; work in this for twenty minutes, and wring out, and put them 
 immediately into a separate vessel filled with lime-water, No. 54, and work 
 in this for fifteen minutes • wring out, and expose to the air for hslf an 
 hour, when the goods will assume a buff colour. 
 
 If the colour is not sufficiently deep, this operation may be repeated, 
 working through the same copperas solution, but using fresh lime-water 
 each time ; the goods are then washed through clean warm water and 
 dried. 
 
 144. Another Method. 
 
 To a vessel of warm water add half a pint nitrate of iron, No. 15, 
 and work the goods in this twenty minutes ; wring out, and work for 
 fifteen minutes in another vessel filled with warm water, to which has 
 been added half a pint caustic potash or soda, Nos. 11 and 12 ; then wash 
 through warm water, and if the colour is not deep enough repeat the 
 operation ; wash again, wring out, and dry. 
 
COTTON DYEING. 
 
 377 
 
 If a little soap be used in the last washing water of either of these 
 two buffs, the colour is improved. 
 
 145. Another Method. 
 
 Add to a tub of water in which the goods are to be dyed half a pint 
 annotta, No. 40, and j oz. bichromate of potash in solution; work the 
 goods in this for fifteen minutes ; lift them out, and add to the liquor % oz- 
 acetate of lead in solution, and work twenty minutes in this ; wring out 
 and dry. By adding more of these stuffs a variety of shades of light fawn 
 or dark buffs may be dyed. 
 
 146. Drab. 
 
 Work the goods for fifteen minutes in a decoction of ^ lb. sumach ; 
 lift, and add 1 oz. copperas in solution and work for fifteen minutes ; wash 
 out in cold water, then work for fifteen minutes in a decoction of 4 oz. 
 fustic, 2 oz. limawood, and 1 oz. logwood ; lift, and raise with 1 oz. alum 
 in solution ; work ten minutes longer, wring out, and dry. 
 
 A great variety of shades can be produced by this means, varying the 
 proportion of the limawood, fustic, and logwood, and different depths by 
 varying the quantities of sumach and copperas. 
 
 147. Olive Drab. 
 
 Work fifteen minutes in lb. sumach, then add 1 oz. copperas, and 
 work in this for fifteen minutes ; wash in a tub of water, and work in ^ lb, 
 fustic for twenty minutes, and raise with 1 oz. alum ; work ten minutes, 
 and dry out. 
 
 148. Rich Reddish Drab. 
 
 To a tub of hot water add one pint of annotta, No. 40, which gives a 
 light salmon colour; then proceed with this exactly as No. 147, or a 3 
 No. 146, by which a great variety of drabs may be dyed. 
 
 149. Stone Colour. 
 
 Work the goods twenty minutes in a decoction of 1 lb. sumach ; lift, 
 and add 1 oz. copperas in solution ; work fifteen minutes, and wash in cold 
 
378 
 
 DYEING RECEIPTS. 
 
 water ; then work ten minutes in warm water, to which half a pint alum 
 plumb liquor, No. 37, has been added ; wring and dry. 
 
 This gives a reddish tint ; but if this tint be not required, the alum 
 plumb may be dispensed with, using £ oz. alum in the washing water. 
 
 150. Catechu Stone Drab. 
 
 Work the goods for fifteen minutes in 2 pints catechu, No. 41, in hot 
 water ; lift, and add 2 oz. copperas in solution ; work for fifteen minutes, 
 and wash in cold water. To another tub of warm water add a decoction 
 of 2 oz. logwood ; work the goods in this for ten minutes ; lift, and raise 
 with % oz. alum ; work ten minutes longer; wring out and dry. 
 
 151. Catechu Drab. 
 
 Work the goods for fifteen minutes in hot water, to which has been 
 added 1 pint catechu, No. 41 ; then lift, and add 1 oz. copperas ; work ten 
 minutes, and wash out and dry. 
 
 A variety of tints may be obtained by topping with a little different 
 woods, as No. 145, proceeding in the same manner. 
 
SILK DYEING. 
 
 PRELIMINARY REMARKS. 
 
 In the introductory part, page 339, we gave the method of preparing silk 
 for dyeing in the hank ; but a great portion of the dyeing required 
 by the amateur is re-dyeing, such as ribbons, handkerchiefs, dresses, 
 shawls, etc. The first operation with goods to be re-dyed is steeping in 
 a strong and warm solution of soap for a few hours, in order to remove 
 stains of oil or grease ; they are afterwards washed in water, and if the 
 colour remaining upon them after this operation be light and equal, and 
 the colour wanted be dark, then no more cleaning is required ; but if 
 unequal, they should be put into a sour, No.- 14, for fifteen minutes, then 
 washed out, and proceeded with for the colour required. 
 
 The following quantities of dye-stuffs given in these receipts are for 
 dyeing 5 lbs. weight of silk. In cases where the silk is very hard-spun, as 
 in some ribbons and dresses, a little more dye-stuff may be used than the 
 quantities given, and also a little more time allowed. Some kinds of goods 
 will be more bulky than others of the same weight ; in such cases, less 
 or more water may be used accordingly. The quantity of water must 
 always be sufficient to allow the goods to be quite Ibose when immersed 
 under the surface. 
 
 When goods are washed from the dye, it is always in cold water, 
 except otherwise mentioned in the receipt. 
 
 The remarks we made about cotton re-dyes are equally applicable for 
 for goods that have been worn, the exposed parts are faded, the other 
 parts dark; except the whole colour can be entirely removed, the re-dye 
 must be dark to hide the inequalities by former wear. 
 
 DYEING. 
 
 * 152. Black. 
 
 Work for an hour in a solution of 8 oz. of copperas, and wash well out 
 in cold water ; then work an hour in a decoction of 4 lbs. of logwood, 
 adding to it £ pint of urine ; lift out, and add to the logwood liquor 2 oz. 
 copperas in solution ; work fifteen minutes; wash and dry. 
 
 This will give a good black, not very deep. If a deep black is required, 
 add to the copperas solution of first operation 2 oz. by measure nitrate of 
 iron, No. 15 ; indeed, for re-dyes it will be better to add this at all times. 
 If a blue shade is required instead of adding urine dissolve a little white 
 soap in the logwood liquor, and add no copperas. 
 
380 
 
 DYEING RECEIPTS. 
 
 153. Full Deep Black. 
 
 Work an hour in 1 lb. copperas and 2 oz. nitrate of iron, No. 15; wash 
 and work for an hour in a decoction of 5 lbs. logwood, and 1 lb. fustic; lift, 
 
 and add 2 oz. copperas, work ten minutes ; wash and finish. 
 
 If the colour is not deep enough, add a little more logwood before 
 raising with the copperas. 
 
 154. French Black. 
 
 Work an hour in 1 lb. copperas and 4 oz. alum; wash well, and then 
 work an hour in a decoction of 4 lbs. logwood, in which a little white soap 
 has been added ; wash out and finish. This black should have a purplish 
 tint. 
 
 155. Blue Black by Prussiate. 
 
 Dye a deep Prussian blue as described No. 110, and work from the 
 prussiate for half an hour in 8 . oz. copperas ; wash well from this in cold 
 water, and then work for half an hour in a decoction of 2 lbs. logwood, 
 using neither urine nor soap in it; lift and add a little of the copperas 
 solution with which the goods were mordanted ; work other ten minutes, 
 then wash and dry. 
 
 156. Deep Hat Black, or Paris Black. 
 
 Work the silk fifteen minutes in a decoction of 2 lbs. fustic and 1 lb. 
 bark ; lift, and add in solution 6 oz. verdigris and 6 oz. copperas ; work 
 other fifteen minutes, and then sink the whole under the surface, and let it 
 steep for several hours, say overnight; lift and wash from this, then make a 
 decoction of 5 lbs. of logwood ; dissolve in it as much white soap as will 
 make a lather, and work in this for an hour ; wash out and dry. A heavy 
 black is dyed by steeping the silk in a decoction of valona nut or husks of 
 the acorn, and then passing through a copperas solution, washing out, 
 and finishing through logwood. 
 
 157. Mixed Black. 
 
 Coal-tar black dyed direct upon silk is not very common; but by 
 dyeing a bluish purple or mauve, see Mauve, and then dyeing a deep blue 
 
SILK DYEING. 
 
 381 
 
 over this, as given further on, a very clear bright shade of black can be 
 obtained, but not so fast as the other black when exposed to light. 
 
 158. Brown. 
 
 Dye an orange with annotta, No. 40 (see Orange), then work for 
 fifteen minutes in a solution of 8 oz. copperas ; wash well from this, and 
 then work half an hour in a decoction of 3 lbs. fustic, 8 oz. logwood, and 1 
 pint archil liquor; lift, and add 2 oz. alum in solution ; work ten minutes, 
 wash and dry. 
 
 1 lb. of Brazil or peachwood may be substituted for the archil liquor 
 with nearly the same results. A variety of this shade of brown may be 
 dyed by varying the quantity of each stuff. 
 
 159. Brown. 
 
 Dye an orange by annotta, No. 40 (see Orange); wash out, and then 
 work for twenty minutes in a decoction of 3 lbs. fustic, 8 oz. sumach, 8 oz. 
 peachwood ; lift up, and add 3 oz. of copperas in solution ; work other 
 fifteen minutes, wash out in two waters, using 2 oz. of alum in solution in 
 the last water. 
 
 If the particular tint required is not obtained by the above propor- 
 tions, it may be given in the water with the alum, using it a little warm. 
 If yellowness is required, add fustic. If redness is required, add peach- 
 wood. If depth or blueness, add logwood. 
 
 A great many particular hues of brown may be dyed by this method ; 
 as for instance, by using only fustic and sumach in the second operation 
 a California brown is obtained, &c., as just referred to, so that any 
 intelligent person will easily regulate his colours and tints. California 
 brown is a yellow fawn brown, something like that now called Bismarck. 
 
 160. Red Browns. 
 
 Dye a deep orange by annotta, No. 40 (see Orange); wash out, then 
 work for fifteen minutes through the plumb liquor, No. 36; wash well 
 and dry. 
 
 Particular tints may be given by adding either logwood, peachwood, 
 or fustic in the last washings, as described in last receipt. 
 
382 
 
 DYEING RECEIPTS. 
 
 161. Another Method. 
 
 Steep the silk in an alum solution of 8 oz. to the gallon for an hour, 
 and wash out in warm water ; then work half an hour in a decoction of 
 1^- lb. fustic, 1£ lb. peachwood, 8 oz. logwood ; lift, and add 1 pint of the 
 alum solution, work for ten minutes ; wash and dry. 
 
 162. Chocolate Brown. 
 
 Steep the silk for an hour in alum, 1 lb. to the gallon water; wash once 
 in warm water, and then work for half an hour in a decoction of 3 lbs. 
 peachwood and 1 lb. logwood; lift, and add 1 pint of the alum solution; 
 work in this for fifteen minutes ; wash out and dry. 
 
 Deeper shades of chocolate are obtained by using a little less peach- 
 wood and more logwood, in equal proportions. A little fustic, say 4 oz., 
 may be added, which will give a still deeper hue if required. 
 
 163. Bronze Brown. 
 
 Work for half an hour in a decoction of 8 oz. fustic, to which 4 oz., 
 by measure, of archil liquor has been added; then lift, and add 2 oz. 
 solution of copperas ; work fifteen minutes, wash in cold water, and finish. 
 A little alum in the washing water will vary the hue a little. 
 
 164. Another Method. 
 
 Work for ten minutes in 1 oz. of “ Bismarck brown,” No. 80, at a heat 
 of 120 <? ; wring out, and work in another vessel containing 3 oz., by mea- 
 sure, of archil liquor ; wring out and dry. Different shades of this colour 
 can be produced by varying the quantities of each. 
 
 165. Safflower Pink. 
 
 Prepare the safflower as described, Nos. 49 and 50 ; then take a 
 quantity of solution equal to 1 lb. of safflower originally used ; add to 
 this solution 1 oz., by measure, vitriol ; enter the silk, and work for half 
 an hour ; then wash in a vessel with warm water in which about 1 oz. 
 cream of tartar has been dissolved ; wring out and finish. Lighter or darker 
 
SILK DYEING. 
 
 383 
 
 shades may be dyed by using less or more safflower— when more is used, a 
 little more time will be required. 
 
 If safflower extract be used, which is simply the red colouring matter 
 of safflower, No. 50, precipitated by an acid, add about two gills of the 
 extract to warm water, with half a wine-glassful of vitriol; stir well ; work 
 the goods in this, and proceed as above. 
 
 166. Safflower Rose and Crimson. 
 
 Dye the goods first a good shade of lavender by working it in archil, 
 see Lavender on silk ; it is then dyed with the safflower above the lavender’ 
 exactly as the pink, but using more dye ; from % lb. to 1 lb. safflower to each 
 pound of silk will give from a rose to a crimson, using a corresponding 
 quantity of vitriol to raise the colour, and requiring from an hour and a half 
 to two hours’ time working; it is finished by washing in warm water 
 made acid to the taste with cream of tartar, the same as the pink. 
 
 167. Safflower Scarlet. 
 
 Dye the silk first a good shade of orange by annotta, No. 40 (see 
 Orange); wash from this, and then enter into the safflower, proceeding in 
 the same maimer as for rose or crimson. For a good rich scarlet, it will 
 require as much safflower as the crimson, 1 lb. to the pound of goods, and 
 finished m the same manner. 
 
 168. Cochineal Crimson. 
 
 To every gafion of water used, add about 2 oz., by measure, bichloride 
 of tm, Nos. 27 and 28 ; allow any sediment to settle, and take the clear 
 solution, and apply heat ; when warm, work the goods in it for an hour or 
 more. 
 
 Boil m a bag 2 lbs. of cochineal, by suspending it on the surface of 
 the water for half an hour; add this to the proper quantity of water for 
 working the goods, the whole being at hand heat ; wring the silk from 
 the spirits, and work it in this cochineal solution for half an hour then 
 set it in steep for several hours, keeping well under the liquor ; wash well 
 out of this in cold water. If the shade is not blue enough, a little cochineal 
 
384 
 
 DYEING RECEIPTS. 
 
 dissolved in ammonia, No. 55, may be added to the water; and after 
 working in this for ten minutes, wring out and dry. 
 
 169. General Remarks. 
 
 Connected with different shades of red, crimson, scarlet, &c., there 
 are a great variety of such shades dyed with the coal-tar colours on silk, 
 the colouring matters being sold under different marks and names, gene- 
 rally with instructions how to dye with them ; with silk there are no pre- 
 parations required as mordants, &c. We repeat Mr. Perkins’ statement 
 upon this, — “ In silk-dyeing the principal difficulty experienced m applying 
 the coal-tar colours was owing to their great affinity for the fibre, thus 
 preventing the dyer from obtaining an even colour, especially when dyeing 
 light shades. After a time, however, it was found that this obstacle could 
 be overcome by dyeing the silk in a weak soap lather, to which the colour 
 had been added. This not only caused the dyeing to proceed with less 
 rapidity, but also kept the face of the silk in good condition. Silk dyed 
 by this process is left soft, but may afterwards be rendered hard or ‘ scroop,’ 
 by rinsing in a bath of slightly acidulated water. 
 
 These remarks apply to almost all the coal-tar colours upon silk. We 
 need hardly add here, that although the different colouring matters can be 
 had ready for use, the intelligent dyer will observe that by mixing one 
 with another a great variety of tints can be produced. 
 
 170. Aniline Pink. 
 
 Dissolve j oz. of the colouring matter called saffronine in a separate 
 vessel, have as much white soap dissolved in the bath as will produce a 
 good lather, then add the dissolved colouring matter, and work the goods 
 in this until the colour in the bath is pretty well exhausted; lift, and 
 wring out and dry. 
 
 171. Aniline Red. 
 
 Into a bath, at a heat of 120°, in which is dissolved some white soap, 
 put 1 lb. of the colour called red paste, marked No. 1. Stir well, then 
 work the goods in this for twenty minutes. Deeper or lighter shades may 
 be had by using less or more of the paste. If a bluer shade of red be 
 wanted, use the paste marked No. 3. 
 
SILK DYEING. 
 
 385 
 
 172. Common Red. 
 
 Make a decoction of 2 lbs. peachwood and 1 lb. fustic, No. 42 ; work 
 the goods in this for fifteen minutes; lift up, and add 4 oz., by measure, 
 red spirits, No. 29; work again fifteen minutes; wash in cold water, and 
 finish. 
 
 A variety of tints may be dyed in this way, by varying the proportions ; 
 and by adding a little logwood, clarets and such shades can be produced ; 
 but these common colours do not stand the air well. 
 
 173. Cochineal Pink. 
 
 This colour is dyed in the same manner as No. 167, only using much 
 less cochineal; about £ lb. will make a good colour. Different shades of 
 pink, rose, and crimson can be dyed by this method, by varying the 
 quantities of stuff used. 
 
 174. Cochineal Scarlet. 
 
 Dye a deep orange by annotta, No. 40 (see Orange); then wash and 
 proceed in the same way as for crimson, passiug through the spirits, and 
 then cochineal, as stated above. 
 
 175. Common Crimson. 
 
 Into a copper or stoneware vessel put some of the peachwood plumb 
 liquor, No. 38; work the goods in it for half an hour; then wash out in 
 cold water until no taste of the plumb liquor is perceptible in the cloth ; 
 wring and dry. 
 
 176. Common Scarlet. 
 
 Dye the goods an orange by annotta, No. 40 (see Orange); wash in 
 water, and then work in the peachwood plumb liquor, No. 38, in the same 
 way as dyeing common crimson ; wash out and dry. 
 
 177. Rubies, Maroons, &c. 
 
 Take 1 lb. of cudbear and boil for fifteen minutes in a bag ; work the 
 silk in this solution for half an hour. If the shade required be of a bluish 
 tint, lift, and add 3 oz., by measure, liquid ammonia; work ten minutes, 
 and wring and dry. 
 
 If the shade required be of a red hue, lift, and add 2 oz., by measure, 
 red spirits, No. 29 ; work ten minutes ; wash out and dry. 
 
 If a brown hue is wanted, use along with the cudbear a decoction of 
 4 oz. fustic ; work in this, and raise with 2 oz. red spirits, as above. 
 
 If a deep violet hue is required, use along with the cudbear a decoc- 
 tion of 4 oz. logwood ; work in it, and raise with 2 oz. red spirits, as above- 
 
 2 b 
 
386 
 
 DYEING RECEIPTS. 
 
 178. Rubies, &c. 
 
 Into a bath, at a heat of 150°, in which is dissolved a quantity of white 
 soap to raise a good lather, put in ^ oz. of the dye known as Schumacher’s 
 No. 8 ; work in this for about twenty minutes. 
 
 179. Sky Blue. 
 
 To 1 pint of sulphate of indigo, No. 44, add 2 or 3 gals, boiling water ; 
 put into this a piece of woollen cloth, such as an old blanket; after 
 steeping for a day, take it out and wash in cold water. 
 
 If the sky blue required be very light, make up a vessel with warm 
 water, about blood heat, steep the blue cloth in this for a few minutes, and 
 wring out, when as much blue will be dissolved off as will -dye the silk ; 
 add 1 oz. of alum in solution, and work the silk in this for twenty minutes ; 
 wring out and dry. 
 
 If the blue required be deep, then to the warm water in which the 
 blanket is put add 1 oz. of pearlash, and proceed as detailed ; but before 
 adding the silk, a few drops of vitriol may be added with the alum to 
 neutralise the alkali. 
 
 If indigo extract be used, Nos. 45, 46, and 47, then the blanket or 
 woollen cloth is not required, but to the requisite quantity of water add 
 ^ oz. of extract, with 1 oz. of alum in solution, and work the silk as stated; 
 less or more of the extract is used according to the depth of shade 
 required. 
 
 180. Prussian Blue — Sky. 
 
 To a sufficient quantity of cold water in which to work the goods, 
 add half pint of nitrate of iron, No. 15 ; work in this for twenty minutes, 
 then wash in cold water. 
 
 Into another vessel of cold water add 3 oz. yellow prussiate of potash 
 in solution, and 1 oz., by measure, of vitriol; work through this for ten 
 minutes, then wash in cold water in which an ounce of alum has been 
 dissolved, and finish. 
 
 181. Royal Blue. 
 
 To a vessel of cold water add 2 pints of nitrate of iron, No. 15; 
 then take 1 pint water and ^ pint muriatic acid, and to this add 3 oz. 
 
SILK DYEING. 
 
 387 
 
 crystals of tin, No. 26; when dissolved, add this to the vessel containing 
 the iron, or instead add 1 pint double muriate of tin, No. 33 ; stir well, 
 and enter the goods immediately, and work for half an hour. 
 
 In another tub dissolve 8 oz. yellow prussiate, and add to it 2 oz., 
 by measure, of vitriol; wring the goods out of the iron solution and put 
 them directly into the second vessel with the prussiate, working for fifteen 
 minutes ; then wash out in cold water, having 2 oz. of alum dissolved in it, 
 and finish. 
 
 Should the shade not be sufficiently deep, instead of washing in the 
 alum water, put them back into the iron solution, and again through 
 the prussiate in the same way, and work the same time as first, only 
 adding 2 oz. yellow prussiate before entering the second time into the 
 prussiate vessel ; then finish as stated. 
 
 Deeper shades are obtained by using more iron and tin, or by giving 
 several dips. 
 
 Some wash the goods out the iron solution in one water before putting 
 them into the prussiate, and also wash out the prussiate before putting 
 back to the iron ; the shade by this will not be so deep with the same 
 stuff, but there is less risk of an unequal colour. 
 
 182. Another Method, or Napoleon Blue. 
 
 Put into a vessel with cold water 2 pints nitrate of iron, No. 15, 
 and 2 pints protochloride of tin, No. 26 ; work in this for half an hour ; 
 into another vessel with water put in a solution of 10 oz. yellow prussiate, 
 1 lb. alum, and 4 oz., by measure, muriatic acid ; wring the goods out the 
 iron solution, and put into the prussiate without washing, and work fifteen 
 minutes. If not deep enough, pass again through the iron, and then the 
 prussiate, adding 2 oz. more prussiate ; wash from this and dry. The 
 goods may be softened a little by mixing oil and tartaric acid, and adding 
 a little of this to the last water ; the goods should be dried by heat. 
 
 If red prussiate of potash be used instead of yellow, as some prefer, 
 then the iron used in first operation should be protomuriate, No. 18. 
 
 This shade of blue has a wine colour tint, and is much admired. 
 
 18j8. Alkaline Blue. 
 
 Alkaline blue is the technical name of the colouring matter of a rich 
 blue dye from coal tar. To a bath made up with a soap solution, at a heat 
 
388 
 
 DYEING RECEIPTS. 
 
 of 150°, add 4 oz. of alkaline blue, and work in this for half an hour. This 
 gives a beautiful rich deep blue. Lighter shades may be got by using a 
 smaller quantity of the dye. 
 
 184. Aniline Blue. 
 
 To the bath, filled with hot water, add 2 oz. of what is termed 
 Nicholson’s blue, marked B B B B, previously dissolved in boiling water ; 
 work in this at a heat of 100 p for twenty minutes ; wash from this, and 
 finish through acidulated water made to taste sour with sulphuric acid. 
 
 185. Lavender. 
 
 Into as much water as will serve to work the goods in easily, put one 
 pint of plumb liquor. No. 33 ; stir well, and work the goods in this for 
 twenty minutes, then wash out in cold water and dry. 
 
 Darker or lighter shades can be dyed by using less or more of the 
 plumb liquor. 
 
 If a blue tint of lavender is required, add to the plumb liquor 
 solution, before putting in the goods, two or three drops of sulphate 
 of indigo, or extract, No. 45 or 46, and proceed as stated. 
 
 186. Lavender — Another Method. 
 
 Into a vessel with warm water as hot as the hand can bear, dissolve a 
 little white soap, enough to raise a lather ; then add one gill archil liquor, 
 and work the goods in this for fifteen minutes ; wring out and dry. 
 
 Boil 1 oz. of cudbear, and add the solution to the soap and water, 
 instead of archil, which will give a lavender having a redder tint than that 
 with the archil. If a still redder shade of lavender be required, the soap 
 may be dispensed with. 
 
 187. Wine Colour, Violet, Lilac, &c. 
 
 Into a copper pan or stoneware vessel put as much of the plumb 
 liquor, No. 36, as will serve to work the goods in ; then work in this for 
 twenty minutes ; wash out in two or three waters, or until the goods 
 have no taste of the plumb liquor, then dry. 
 
 If a rich blue tint is required, add to the plumb 1 oz., by measure, 
 sulphate of indigo, or extract, No. 45 or 46. If a red tint is required, dye 
 the cloth first a lavender by cudbear, No. 186, without soap ; then work 
 through the plumb liquor without indigo. 
 
SILK DYEING. 
 
 389 
 
 The plumb liquor used for this colour is not thrown away ; it is either 
 put back into the stock tub or into another vessel kept for that purpose, 
 when it may be used over again. If indigo has been used, it must not be 
 put back into the stock plumb, or it will give the whole a blue shade ; all 
 such mixtures should be kept separate. 
 
 188. Violet. 
 
 To the bath, raised to a heat of 120° Fall., add 1| oz. of “ methy- 
 lated violet,” marked No. 10, 12 oz. white tartar, and 6 oz. ground alum, 
 previously dissolved ; work the goods in this for thirty minutes ; wring 
 out and dry. 
 
 189. Hofmann’s Violet. 
 
 To a bath of water, at 100° Fah., with soap making a lather, put 
 in 1 gill of Hofmann’s solution, RRR; work in this for half an hour, 
 or until the colour is pretty well taken up. This may also be wrought 
 with tartar and alum, as the above. The great drawback to these purples 
 or violets is their fading by exposure to light. 
 
 190. French and Pearl White. 
 
 In hot water dissolve a quantity of white soap, as much as makes a 
 lather, and then add about ^ oz., by measure, archil ; work the goods in 
 this for ten minutes, and finish out the soap. 
 
 A little cudbear may be used instead of archil, less or more according 
 to the shade required. 
 
 191. Another Method. 
 
 To a vessel of cold water add about 1 oz., by measure, of plumb 
 liquor ; work the goods for ten minutes ; wash out and dry. 
 
 For these shades the goods should be perfectly white previous to 
 dyeing. 
 
 192. Weld, Yellow. 
 
 Work the silk for an hour in a solution of alum, about 1 lb. to the 
 gallon ; wring out and wash in a vessel with warm water. Boil 2 lbs. 
 weld, strain the liquor, and work the alumed silk in this for half an hour; 
 then add one pint of the alum solution to the weld bath, and return the 
 silk ; work for ten minutes longer, and wring out and dry. 
 
 This gives a rich lemon yellow ; by adding more weld deeper shades 
 are produced ; or by adding a little annotta, No. 40, amber and straw tints 
 are obtained. 
 
390 
 
 DYEING RECEIPTS. 
 
 193. Bark and Fustic Yellow. 
 
 Work the silk for an hour through an alum solution of the strength 
 of 1 lb. to the gallon water, then wash out in warm water and wring. 
 Take 2 lbs. of bark, prepared as No. 42, and work the alumed silk in this 
 solution for half an hour ; lift and add 1 pint of the alum solution ; 
 work ten minutes longer, and wring out and dry. By using fustic instead 
 of bark a very rich yellow is also produced. 
 
 194. Another Method. 
 
 Alum the silk as above, and boil 3 lbs. bark in a bag ; then work the 
 silk through this decoction, while very hot, for half an hour ; lift and add 
 2 oz., by measure, red spirits, No. 29 ; work for fifteen minutes, wash out 
 in cold water ; then work ten minutes in a solution of white soap ; wring 
 out of this and dry. 
 
 195. Gold and Amber. 
 
 Into warm water with white soap add 2 pints annotta liquor, 
 No. 40 ; work in this fifteen minutes ; wash out, and then work twenty 
 minutes through a decoction of 8 oz. bark ; lift, and add 1 oz., by measure, 
 red spirits, No. 29 ; work other ten minutes ; wash out and finish. 
 
 Different tints of these colours may be dyed by varying the quantity 
 of annotta bottom and of the bark. 
 
 196. Nankeen, Buff, Salmon, Flesh, &c. 
 
 Make a solution of white soap in warm water, and to this add 1 pint 
 of annotta liquor ; work twenty minutes, wring out and finish. If the 
 shade is not deep enough, add a little more annotta. 
 
 If a red tint is required, such as salmon or flesh colour, the goods are 
 washed out the soap, and finished in cold water, in which 2 oz. alum is 
 dissolved. By adding a little fustic with the alum, a straw tint, like the 
 pattern attached, will be got. 
 
 * 
 
 197. Orange. 
 
 The silk is wrought for fifteen minutes in a strong solution of annotta, 
 No. 40, made warm ; then washed in warm water and dried. 
 
SILK DYEING. 
 
 391 
 
 The annotta made up for silk should be with soft soap, instead of 
 potash or soda, or only a very little of these alkalies should be added. 
 
 198. Orange — Another Method. 
 
 Dye a very light shade of red, as No. 171, or pink, No. 170; wash 
 out and top by dyeing over this a yellow, with 2 oz. of picric acid ; 
 wring out and dry. 
 
 199. Yellow Drab. 
 
 To a vessel of warm water add 1 pint annotta liquor, No. 40; 
 work in this for fifteen minutes, and wash ; then work other fifteen 
 minutes in a decoction of £ lb. sumach and 1 lb. fustic ; lift up, and 
 add 4 oz. copperas in solution and 1 oz. alum ; work ten minutes ; wash 
 in cold water and dry. 
 
 A variety of shades of drab may be dyed in this way by varying 
 the proportions of the stuff, and addding with the fustic small quantities 
 of logwood and peachwood. 
 
 200. Common Drabs. 
 
 Work the goods for fifteen minutes in a decoction of 8 oz. sumach 
 and 8 oz. fustic ; lift and add 4 oz. copperas ; wash twenty minutes, and 
 wash out in cold water. In another vessel with warm water add l pint 
 archil liquor ; work fifteen minutes in this, and dry out. 
 
 If a greenish tint be required, add a decoction of 4 oz. fustic to the 
 archil, and % oz., by measure, of chemic, No. 48, or a little extract, 
 No. 45. If a purple tint is required add, instead of the chemic, 1 oz. of 
 alum in solution. 
 
 A great variety of tints may be produced by a slight variation of 
 some of these ingredients. 
 
 201. Slate or Stone Colour. 
 
 In a decoction of 1 lb. sumach, 4 oz. fustic, and 4 oz. logwood, No. 
 42, work the silk for half an hour; lift, and add a solution of 4 oz. 
 copperas; work other thirty minutes ; wash in cold water, and finish. 
 
 I 
 
392 
 
 DYEING RECEIPTS. 
 
 A variety of tints can be produced by this method, by varying the 
 proportions of the stuffs. 
 
 202. Common Green. 
 
 Steep for an hour in an alum solution of 1 lb. to the gallon ; wash in 
 warm water, and work for thirty minutes in a decoction of 6 lbs. fustic ; 
 then add 2 oz., by measure, indigo extract, No. 45 or 46 ; work other 
 thirty minutes ; wash and finish. 
 
 Should the shade be too yellow, as the extract often varies in quality, 
 add more extract to the fustic before finishing. 
 
 Deeper and lighter shades are dyed by this method, by using less or 
 more of each stuff. 
 
 203. Another Method. 
 
 Work for forty minutes in a decoction of 4 lbs. fustic ; lift, and add 1 
 lb. alum in solution, and 2 oz., by measure, of indigo extract ; work for 
 half an hour in this ; wash out in cold water having in it ^ pint of the alum 
 solution, No. 202, and finish. 
 
 204. Sage Green and Pea Green. 
 
 Steep the silk for an hour in an alum solution of 8 oz. to the gallon 
 of water, and then wash out in warm water ; boil 4 lbs. ebony wood chips 
 for an hour ; take the clear, and work the silk in it for thirty minutes ; lift, 
 and add \ oz. indigo extract ; work ten minutes ; wash in cold water having 
 \ pint of alum solution, No. 202, in it, and dry. A weak decoction of weld 
 may be used instead of ebony chips. 
 
 Care has to be taken in adding the extract, lest the quantity given be 
 
SILK DYEING. 
 
 393 
 
 too much for the shade required ; it may be better to add less, and if found 
 not enough, lift and add more. 
 
 205. Bottle Green. 
 
 Dissolve 2 lbs. alum and 1 lb. copperas ; work the silk in this for an 
 hour, and wash out in warm water ; then work for half an hour in a 
 decoction of 6 lbs. fustic ; lift, and add 2 oz., by measure, indigo extract, 
 No 45 ; work twenty minutes ; wash out and finish. 
 
 206. Another Method. 
 
 Proceed exactly as described for common green ; but add 1 lb. of 
 logwood to the 6 lbs. of fustic, and operate in every way the same as 
 No. 202. 
 
 If a deeper shade be required, a little more logwood may be added. 
 
 207. Green. 
 
 To a bath heated to 120° add 8 oz. of what is known as new green 
 powder, 8 oz. picric acid, 6 oz. of alum, and 12 oz. of white tartar ; work 
 in this for half an hour. This gives a very deep rich green, but the shade 
 may be varied by varying the quantity of picric acid. 
 
 208. Another Method. 
 
 To a bath with soap dissolved in it, dye a blue, as No. 183 ; wash out, 
 and dye over this a yellow, with 8 oz. of picric acid and 8 oz. of alum ; if a 
 yellowish green is required, use more picric acid; if a bluish green is 
 wanted, use less of this acid. 
 
 209. Olive. 
 
 Work the silk for half an hour in a solution of 1 lb. copperas and 
 4 oz. alum ; wash out in hot water, and then work half an hour in a decoc- 
 tion of 2 lbs. fustic and 4 oz. logwood ; lift, and add £ pint alum solution, 
 No. 202, or 2 oz. dissolved ; work ten minutes in this ; wash and dry. 
 
391 
 
 DYEING RECEIPTS. 
 
 If the shade required have more of a green hue than pattern, add a 
 little chemic, or extract, to the last water, and work ten minutes and dry. 
 
 Dye a light Prussian blue, No. 180, then work for twenty minutes 
 in a decoction of 2 lbs. fustic and \ pint archil liquor; lift, and raise 
 with £ pint alum solution, No. 202, or 1 oz. dissolved ; work ten minutes 
 and finish. 
 
 The intelligent operator will soon be able to apply the proper stuff for 
 the tint required ; but in working with silk avoid strong caustic alkalies, or 
 alkaline earths, such as lime, which affects the fibre, also bleaching liquors. 
 The affinity of silk for dyes is much greater than cotton; it is easier 
 dyed, but strong liquors have a tendency to take away the natural lustre 
 of the silk. 
 
 210. Light Olive. 
 
WOOLLEN DYEING. 
 
 PRELIMINARY REMARKS. 
 
 The preparation of woollen for dyeing has been given (page 339). In the 
 following receipts the quantity of dye-stuffs given are for 10 lbs. of 
 woollen, whether yarn or cloth, and the quantity of liquid used must be 
 sufficient to allow the goods plenty of room in the liquor. The proper 
 quantity of water for a certain quantity of goods will soon become known 
 with a little practice. 
 
 For re-dyes every care should be taken to remove all grease or oil 
 first, or no good dye can follow. This is done by steeping and scouring in 
 soap and soda, No. 2. If the remaining colour be unequal or dark, the 
 goods are steeped or wrought for a little in a sour made up by sal nixon 
 (bisulphate of potash), 2 oz. to the gallon water. 
 
 Woollen is always dyed hot, the liquid generally being near to the 
 boiling point, which necessitates its being dyed in a boiler. Iron vessels 
 are in general not used for this purpose. Copper, and copper with tin, 
 were formerly used. Now wood-baths are generally used, made of a size 
 to dye 50 lbs. or 100 lbs. at a time, having a steam-pipe running along the 
 bottom to give the necessary heat. The dye-stuffs, such as ground wood, 
 are generally put into the boiler, and the goods wrought with them ; but 
 it is cleaner to make a decoction and use the clear liquor. 
 
 All washings to be in cold water, except warm be specified in the 
 receipt. 
 
 DYEING. 
 
 211. Black. 
 
 Work for one hour in a bath of 8 oz. bichromate potash (chrome), 
 6 oz. alum, 4 oz. fustic ; lift and expose to the air for a short time ; wash 
 well, and then work for one hour in another bath of 4 lbs. logwood, 
 4 oz. barwood, 4 oz. fustic ; lift and add 4 oz. copperas in solution ; work 
 half an hour in this, and then wash and dry. 
 
 212. Black. 
 
 Work for twenty minutes in a bath of 8 oz. camwood ; lift and add 
 8 oz. copperas; work other twenty minutes ; then withdraw the fire from 
 the boiler, and submerge the goods in the liquor overnight ; then wash 
 
396 
 
 DYEING RECEIPTS. 
 
 out. In another bath, of 5 lbs. of logwood and 1 pint urine, work for 
 an hour; lift and add 4 oz. copperas; work in this half an hour longer; 
 wash and dry. 
 
 213. Blue Black. 
 
 Dye first a good dark Prussian blue, No. 236, or royal blue ; then 
 proceed in the same manner as in No. 211, using only the half of the stuff 
 named there. If the blue is very deep, instead of operating as No. 211, the 
 goods may be wrought for half an hour in a decoction of 4 lbs. logwood ; 
 then add to this 1 oz. red chromate of potash; work half an hour longer; 
 wash and dry. 
 
 214. Common Black. 
 
 Put into the bath 8 oz. of bichromate of potash, with 5 oz. of red 
 argol; boil these together for a little; put off the boil, and enter the goods, 
 and work for one and a half hours ; then wash out. In a new bath add 
 5 lbs. of ground logwood; work in this at nearly boiling heat for an hour ; 
 wash out and dry. 
 
 Where red argol may not be at hand, common salt may be used 
 instead ; the former is preferable. 
 
 215. Brown. 
 
 Work for half an hour in 8 oz. of chrome; lift and expose till cold; 
 then in a new bath work an hour in 2 lbs. fustic, 4 oz. madder, 3 oz. 
 cudbear, 4 oz. tartar, 2 oz. logwood; lift out and dry; or wash before 
 drying. 
 
 216. Chrome Brown. 
 
 Dissolve in bath 6 oz. bichromate of potash and 3 oz. of tartar; work 
 in this for one and a half hours ; wash well ; make up new bath with 9 oz. 
 cudbear, 2 lbs. fustic ; work in this for one hour ; lift and add \ oz. 
 copperas ; re-enter and work fifteen minutes ; wash out and dry. 
 
 217. Yellow or Light Brown. 
 
 Work for an hour in the following bath: 2 oz. bichromate of potash 
 (chrome), 2 oz. argol, 2 oz. alum; wash from this bath; then work about 
 
WOOLLEN DYEING. 
 
 397 
 
 forty minutes in another bath, made up with 2 lbs. fustic, 1 lb. madder, 
 8 oz. peachwood, 4 oz. logwood; wash out of this and dry. This gives a 
 very beautiful brown; and a great variety of tints and shades may be 
 made by varying the quantities of the last bath with the same preparation 
 as the first bath. 
 
 218. Brown. 
 
 This is a more easily dyed brown than last, although not giving the 
 same tint. Work for an hour in a bath made up with 2 lbs. fustic, 2 lbs. 
 madder, 1 lb. peachwood, 4 oz. logwood ; then lift and add to the bath a 
 solution of 2 oz. copperas, and work half an hour in this ; wash out and dry. 
 
 219. Brown. 
 
 Work for an hour in a bath of 4 lbs. fustic, 2 lbs. camwood, ± lb. 
 logwood; lift and add to the bath 4 oz. copperas; work half an hour in 
 this ; wash and dry. A variety of shades may be dyed in this way by 
 varying the proportions of stuffs. 
 
 220. Madder Brown. 
 
 Make a bath charged with 6 oz. alum, 3 oz. tartar or argol, a lb. 
 madder, and 3 lbs. fustic ; boil these together for some time ; put off the 
 boil and enter the goods, and work for an hour with the liquor at spring 
 of the boil ; lift up and add 2 oz. bluestone and 1 oz. of copperas ; work 
 half an hour ; wash and dry. 
 
 221. Crimson. 
 
 Work in a bath for one hour with 1 lb. cochineal paste, No. 49, 6 oz. 
 dry cochineal, 1 lb. tartar, 1 pint protochloride of tin ; wash out this and 
 dry. 
 
398 
 
 DYEING RECEIPTS. 
 
 222. Magenta. 
 
 To a bath heated to about 170° add ^ oz. of magenta crystals, pre- 
 viously dissolved in boiling water ; work in this for thirty minutes ; wring 
 out and dry. A little soap in solution may be used with advantage. 
 
 223. Scarlet. 
 
 Work for an hour in a bath to which has been added 1 lb. tartar, 2 oz. 
 dry cochineal, 8 oz. sumach, 8 oz. fustic ; wash out and dry. 
 
 224. Another Method. 
 
 To the bath add 12 oz. cochineal, 3 oz. of tartar, \ oz. oxalic acid, 
 1 1 pint of scarlet spirits, and \ oz. flavine; boil all these together for a 
 short time ; then let off the boil and enter the goods, and work for one and a 
 half hour, keeping up the heat close to the boiling point; wash out and dry. 
 
 225. Red. 
 
 Work half an hour in a bath of 1 oz. bichromate of potash, 1 oz. 
 alum ; wash out this through cold water ; then work for half an hour in 
 another bath of 3 lbs. peach or limawood; lift and add 1 oz. alum; work 
 in this for twenty minutes ; wash and dry. 
 
 226. Lac- Scarlet or Red. 
 
 Put into bath 4 oz. of lac-dye, 2 pints of scarlet spirits, 2 oz. crystals 
 of tin in ^ pint muriatic acid, and 8 oz. tartar ; boil these together for 
 fifteen minutes ; let off the boil ; then enter goods, and work for an hour ; 
 wash out and dry. If the colour wanted be more of a scarlet, add some 
 flavine or quercitron bark. 
 
 227. Claret. 
 
 Work for an hour in 5 oz. camwood; lift out and expose until the 
 goods are well drained and cold ; in the interim add to the bath with the 
 camwood 4 oz. copperas, 2 oz. alum, 8 oz. logwood ; work the goods in this 
 for half an hour ; wash and dry. 
 
WOOLLEN DYEING. 
 
 309 
 
 228. Madder Red. 
 
 Work the goods for two hours in a bath having dissolved in it 2 lbs. 
 alum, 5 oz. tartar, and \ pint perchloride of tin ; lift out and expose for 
 an hour ; then work for an hour in a fresh bath charged with 8 lbs. of 
 madder ; wash out and dry. Different shades, down to a salmon-colour, 
 may be dyed in this way, using small proportions of stuff. 
 
 229. Pink. 
 
 Work one hour in a bath of 1 lb. tartar, 8 oz. alum, 1 lb. cochineal 
 paste, 1 gill measure of red spirits, No. 29 ; wash out and dry. 
 
 230. Pink. 
 
 Put into the bath ^ lb. of alum, ^ lb. cream of tartar, ^ lb. tin 
 crystals in half pint muriatic acid, and add to this 1 gill of cochineal paste ; 
 enter the goods after the stuffs are well mixed, and work for half-an-hour; 
 wash and dry. Darker and lighter shades can be had by using less or 
 more paste. 
 
 231. Yellow. 
 
 Work for half an hour in a bath with 3 oz. chrome, 2 oz. alum; lift 
 and expose till well cooled and drained ; then work for another half hour, 
 without previous washing in another bath of 5 lbs. fustic; wash out 
 and dry. 
 
 232. Yellow or Amber. 
 
 Charge the boiler with lb. of alum, ^ lb. cream of tartar, 1 pint 
 double muriate of tin, 1 oz. flavine, and 10 oz. quercitron bark; boil these 
 
400 
 
 DYEING RECEIPTS. 
 
 together for fifteen minutes; allow the liquor to cool till the hand may be 
 held in it, then enter the goods, and bring up the heat to 200° ; work for an 
 hour; wash out and dry. By adding a little cochineal, ambers and oranges 
 may be dyed. 
 
 233. Another Method. 
 
 Work for twenty minutes in a bath with 8 oz. tartar, 8 oz. alum; lift, 
 and add to the bath 2 lb. bark, 8 oz. sumach, 8 oz. fustic, 1 pint red 
 spirits ; work in this for forty minutes ; wash out and dry. 
 
 234. Another Method for Yellow. 
 
 Put into bath 8 oz. alum, 3 oz. tartar, \ oz. flavine, | pint yellow 
 spirits ; boil altogether for ten minutes, then enter the goods and work 
 until they are all of an even colour. This makes a rich amber yellow. 
 
 235. Orange. 
 
 Work for forty minutes in a bath to which has been added 2 lbs. 
 sumach, 3 oz. cochineal dry, 1 lb. fustic, 8 oz. tartar, 1 pint red spirits ; 
 wash out this and dry. 
 
 236. Sky Blue. 
 
 Work in a bath for half an hour with 8 oz. argol, 1 lb. alum, 1 gill 
 indigo extract, No. 45 or 46; wash out this and dry. 
 
 Different depths of shade may be made by varying the quantities of 
 indigo extract. 
 
 237. Aniline Blue. 
 
 Take 3 oz. of Nicholson’s blue, marked B, B, B, B, and dissolve in 
 a gallon of boiling water, then add it to the bath along with a gill silicate 
 
WOOLLEN DYEING. 
 
 401 
 
 of soda ; enter the goods cold, and bring up heat to 180° ; wash and 
 work in a new bath having in it ^ pint sulphuric acid, which brings up 
 the blue ; wash and dry. 
 
 238. Royal Blue. 
 
 Work the goods for twenty minutes in a bath with 1 lb. yellow 
 prussiate of potash, ^nd lift; then take | pint nitrate of iron, No. 15, and 
 add to it 1 oz. of the crystals of tin, No. 26, or 1 pint double muriate of 
 tin, No. 34; stir well for a few minutes, and then add this mixture to the 
 bath, and work the goods in this for half an hour; wash out and dry. 
 
 Different shades of this may be dyed by varying the quantities of all 
 the ingredients. 
 
 239. Another Method. 
 
 Into the required quantity of water put 1 quart of muriate of iron, 
 No. 18, and add to it 1 pint of double muriate of tin, No. 34 ; work in 
 this for half an hour ; lift and work half an hour in a bath with 4 oz. red 
 prussiate of potash. If the colour is not deep enough, repeat this through 
 the same stuff, adding 2 oz. more red prussiate ; then wash out in cold 
 water and dry. 
 
 240. Saxon Blue. 
 
 Work the goods in a bath for thirty minutes, in which 1 pint of 
 indigo extract has been added, and 2 ounces alum, and 1 ounce tartar; 
 wash out and dry ; any shade may be got by giving more or less of the 
 extract. 
 
 241. Pigeon Blue. 
 
 Work in a bath for forty minutes having 2 oz. bichromate of potash, 
 4 oz. alum, 1 oz. tartar ; wash from this in cold water, and then work for 
 half an hour in another bath with 3 lbs. logwood ; lift and add 1 oz. 
 verdigris ; work for fifteen minutes, and wash and dry. 
 
 242. Another Method. 
 
 Charge the bath with 5 oz. bichromate of potash, 9 oz. alum, and 2 oz. 
 tartar ; work in this for half an hour ; lift and drain. 
 
 Into another bath having in it a decoction of 9 oz. logwood, work in 
 
 2 c 
 
402 
 
 DYEING RECEIPTS. 
 
 this for twenty minutes, then add 5 oz. cudbear ; work for forty minutes in 
 this, expose for an hour, and wash and dry. 
 
 243. Oak or Apple Green. 
 
 Work for half an hour in a bath with 1 oz. chrome, 1 oz. alum; wash 
 through cold water, and then work for half an hour in a second bath with 
 2 lbs. fustic and 8 oz. logwood ; wash and dry. 
 
 A variety of this shade can be obtained by varying the proportions and 
 quantities. 
 
 244. Common Logwood Green. 
 
 Work the goods for an hour in a bath having dissolved in it 1|- lb. 
 alum, 5 oz. tartar, and 3 oz. sulphate of copper ; lift and expose for two 
 hours : then into a fresh bath work for half an hour with 1|- lb. fustic 
 and 1 lb. logwood; lift and add to this bath 3 oz. of soda ash, and 1 gallon 
 of stale urine ; work in this for another thirty minutes, wash out and dry. 
 
 245. Common Green. 
 
 Work for fifteen minutes in a bath with 5 lbs. fustic, 2 oz. argol, 5 oz. 
 alum; lift, and add £ gill indigo extract; and then work for half an hour, 
 and dry. 
 
 If the green seem too yellow, a little more extract of indigo may be 
 added. 
 
 246. Fast Green. 
 
 This is first dyed blue in the indigo or woad vat, according to the 
 depth of green required, and then work for an hour in a bath with 4 lbs. 
 fustic, 2 lbs. alum, and dry out. 
 
 By dyeing the blue vat lighter than is required for the green, and 
 adding to the bath with the fustic a little logwood, will give the required 
 depth and a good shade ; but the colour is not so fast. 
 
 247. Bottle Green. 
 
 Work for an hour in a bath with 2 oz. chrome and 4 oz. alum; lift 
 out and expose to the air for some time till the goods are cold; then 
 
WOOLLEN DYEING. 
 
 403 
 
 work for an hour in a second bath with 3 lbs. fustic, 1| lb. logwood; wash 
 out and dry. 
 
 248. Invisible Green. 
 
 Work for an hour in a bath with 3 oz. chrome, 4 oz. alum; lift and 
 expose to the air for some time; then work for an hour in a second bath 
 with 2 lbs. fustic, 3£ lbs. logwood ; wash out and dry. 
 
 By comparing these two last receipts, it will be seen that the different 
 shades are produced by varying the proportions of the same stuffs, and 
 will serve as a guide to the amateur. 
 
 249. Grass Green. 
 
 To the bath add £ lb. of alum, 2 oz. tartar, ^ lb. indigo extract, and 
 6 lbs. fustic ; boil all the stuffs together for ten minutes in bath half -filled 
 with water; then fill the bath with cold water, and enter the goods, and 
 raise the heat slowly to the boiling point ; w'ork at this heat for half an 
 hour, then wash and dry. 
 
 250. Olive. 
 
 Work for an hour in a bath with 10 oz. fustic, 8 oz. logwood, 4 oz. 
 madder, 2 oz. peachwood ; lift, and add to the same bath 4 oz. copperas in 
 solution, and work for half an hour and dry. 
 
 251. Olive. 
 
 Work for an hour in a bath with 4 oz. chrome, 2 oz. alum; lift and 
 expose for some time to the air; then work for an hour in a bath with 
 3 lbs. fustic, 1|- lb. camwood, 1 lb. logwood; lift out and dry. 
 
 252. Purple. 
 
 Work the goods half an hour in a bath, with 1 oz. chrome, 1 oz. 
 alum ; lift out and wash, and then work half an hour in a bath with 2 lbs. 
 logwood, 1 lb. peachwood; lift, and add 1 oz. of alum in solution; work 
 in this for twenty minutes; wash and dry.’ 
 
404 
 
 DYEING RECEIPTS. 
 
 If a light and redder shade be required, use less logwood and more 
 peach wood ; and if a darker shade, more of each. 
 
 253. Hofmann’s Violet. 
 
 Put into bath, when it is lukewarm, 1 gill of Hofmann’s R, R, R; put 
 in the goods, and bring the heat slowly to the boiling point; work until 
 the colour is level. By adding a little alum and tartar, it gives a bluer 
 tint than when alone. 
 
 254. Peach, to Wine Colour. 
 
 Work the goods for an hour in a bath with 4 lbs. cudbear, and dry. 
 
 If a darker shade be required, give more cudbear; if the tint be 
 required bluer, add, after half an hour’s working, 1 gill ammonia or 
 hartshorn; if a redder tint is required, add a wine-glassful of muriatic 
 acid. 
 
 If the acid be added, the goods should be washed before drying. 
 
 255. Light Violet. 
 
 Work for an hour in a bath with 4 oz. cudbear, 4 oz. logwood, 2 oz. 
 barwood or camwood, 2 oz. peachwood ; lift and add 2 oz. alum in solu- 
 tion, and work half an hour and dry. 
 
 256. Perkin’s Mauve Original Colour. 
 
 Add 1 gill of the colour to the dye bath ; *when the water is lukewarm 
 enter the goods, and bring the liquid slowly to the heat of 180° ; continue 
 to work till the colour is level. Light shades of this is difficult to get 
 level. Alum may be used with this, but it hurts the fastness of the dye. 
 
WOOLLEN DYEING. 
 
 405 
 
 257. Common Puce. 
 
 Work in a bath for one hour with 10 oz. logwood, 1 oz. camwood, 
 8 lbs. cudbear; lift and add 2 oz. copperas in solution; work half an hour 
 and dry. 
 
 258. Puce or Purple. 
 
 Dissolve oz. of Perkin’s purple in a pint of warm alcohol and filter 
 it, adding the filtrate to the bath along with 6 oz., by measure, of acetic 
 acid, 6 oz. alum, and 2 oz. tartar; enter the goods at hand-heat, and bring 
 the liquor to the boil, working for an hour ; wash out and dry. If a blue 
 shade is required — something approaching to mauve — add to the bath 
 about a wine-glassful of vitriol ; if a redder shade is required, add a little 
 magenta dye. 
 
 259. Greenish Drab. 
 
 To the dye bath add 1 oz. bichromate of potash, ^ oz. alum, £ oz. 
 tartar, and work the goods in this half an hour; lift out and wash. Make 
 up a new bath of water, and add 4 oz. logwood, 2 oz. fustic, 1 oz. barwood, 
 or £ oz. peachwood ; work the goods again through this second bath half 
 an hour; wash and dry. 
 
 Shades of this can also be varied by using different proportions of 
 stuffs. 
 
 260. Brown Drab. 
 
 To the dye bath add 2 oz. ground madder, 1 oz. peachwood, 2 oz. 
 logwood, 6 oz. fustic, and work in this for thirty minutes ; lift up and add 
 3 oz. of copperas in solution; mix well, and work the goods in this for 
 other thirty minutes ; wash and dry. 
 
 This shade can be greatly varied, either by altering the quantity of 
 the stuffs, or the proportions of any of them; if a redder tint be required, 
 add more peachwood or madder— the latter gives the drab hue; if more 
 yellow, add fustic ; if more slate or black, add logwood, and vice versa. 
 
 261. Light Grey. 
 
 To a bath half filled with water add 2 oz. of tartar, £ oz. of ground 
 nut-galls, 1 oz. of cudbear, and \ oz. of logwood, and boil fifteen minutes; 
 then fill up the bath with cold water and enter the goods, and work 
 rapidly till the heat comes tp the boiling point, continuing working the 
 goods for forty minutes. This is required in order to have an even dye 
 with so little stuff; lift and add £ oz. of copperas; work other twenty 
 minutes, then wash and dry. This gives a very light shade of grey — of 
 course, darker shades can be obtained by more stuff. 
 
406 
 
 DYEING RECEIPTS. 
 
 262. Grey Drab. 
 
 Dissolve £ oz. of bichromate and add to it the required quantity of 
 water ; work the goods in this for half an hour ; then lift and add 1 oz. 
 of logwood ; work again for half an hour ; wash and dry. 
 
 Different shades of this drab may be made by varying the quantities 
 of the dye-stuffs. 
 
 263. Another Method. 
 
 To the bath one-fourth full, add 6 oz. alum, 2 oz. tartar, l oz. indigo 
 extract, \ oz. Perkin’s mauve, ^ oz. cochineal, | oz. cudbear, and 1 oz. fustic ; 
 boil together ; then fill bath with cold water, enter the goods, and raise 
 the heat to the boiling point, and continue working till level ; wash and dry. 
 
 264. Slate Drab. 
 
 Into the proper proportion of water add 1 oz. peach or lima-wood, 
 2 oz. logwood, % oz. fustic ; work in this for twenty minutes, and then lift 
 out, and add to the dye bath 1 oz. sulphate of iron (copperas) in solution ; 
 stir well and work in this for another half hour ; lift out and expose to the 
 air for a short time ; wash and dry. 
 
 A great variety of shades of slate or stone colours may be dyed by 
 varying the quantities and the proportions of the dye-stuffs. 
 
 265. Slate or Stone Colour. 
 
 Work for half an hour in a bath with 8 oz. logwood, 1 oz. fustic ; lift 
 and add to the bath a solution of 1 oz. alum, ^ oz. copperas ; work in this 
 half an hour ; wash and dry. 
 
 If a bluer tint be required, use less alum and more copperas ; if 
 more to the purple, less fustic and more alum ; and so, by a very little 
 practice, any particular tint can be obtained. 
 
WOOLLEN DYEING. 
 
 407 
 
 266. Blue by Woollen Blue Yat. 
 
 The blue vat No. 39 is not used for woollen or silk ; for these fibres 
 there are two sorts of vats used, to set which and keep in order requires 
 great experience, and many extensive dye-houses do not possess them. 
 The dyer who keeps these has always something different to his neigh- 
 bour which he prefers and keeps secret. A very good method for setting 
 a woad vat is as follows : — Into a large and deep iron vessel, capable of 
 being furnished with a steam jacket, put, for every 20 gallons water, 
 12 lbs. best woad finely chopped, 1 lb. ground indigo, 3 oz. madder, 3 oz. 
 bran; mix well, and let them steep from sixteen to twenty hours at 
 bloodheat; when they begin to ferment, and the colour of the solution 
 becomes yellowish, a little lime is added and the vat stirred ; this stirring 
 should be continued every four or five hours, and either lime, madder, 
 or potash added in small portions according to the appearance of the 
 solution; when in good order, there should be on the surface a thin float- 
 ing layer of indigo, and when the liquor is blown upon, it should have 
 an amber tint with blue veins ; if too yellow, a little lime is added. It 
 requires several days before the vat can be dyed with. 
 
 To dye silk in this vat, the liquor should only be lukewarm; to dye 
 woollen it should be heated to about 170° Fah. The heat must not be 
 applied to the bottom of the vat, which would raise the sediment, but to 
 the sides by the steam jacket above the sediment. 
 
 267. Another Blue Yat for Woollen. 
 
 In a similar vessel to the above add, for every 20 gallons water, 5 oz. 
 ground indigo, 8 oz. potash, 3 oz. madder, and 4 oz. bran ; keep the 
 solution at a heat of 140° Fah. ; after twenty-four hours the whole will 
 have begun to ferment; then add 2 oz. madder; stir, and allow the whole 
 to settle, after which the vat is ready for use. Woollen is dyed in this 
 in the same way as last — heating the vat to 170°, working the goods in it 
 for a short time, then exposing to the air for an hour. If the shade is deep 
 enough, wash and finish; if not dark enough, give another dip. (See the 
 chapter upon Indigo and the principle of these vats.) 
 
MIXED FABRICS. 
 
 DYED TWO COLOURS. 
 
 Mixed fabrics of cotton and woollen, as coburgs and damasks, are very- 
 common ; these are either dyed all one colour, or the cotton and woollen 
 are dyed of different colours. This last is seldom done, except with new 
 goods, or in cases where very light coloured goods are wanted a dark 
 shade, in which case a light and dark colour may be dyed. The process 
 for doing this is very simple. As the process used for woollen will 
 seldom produce the same colour on cotton, the two have to be dyed 
 separately. For most colours it is necessary to dye the woollen first, and 
 then the cotton ; in a few the cotton is dyed first. In most cases, the 
 processes we have given will serve the purpose ; as for instance — 
 
 268. Green and Pink. 
 
 The woollen is first dyed a green, by the process No. 245, and then 
 the cotton is dyed pink, by the process No. 87. 
 
 269. Green and Crimson. 
 
 Dye the woollen by working for an hour in 2 lbs. tartar, 4 lbs. alum, 
 6 lbs. fustic, and then add | pint indigo extract, No. 45 ; wash out and lay 
 overnight in 6 lbs. sumach ; work half an hour in red spirits, No. 29, made 
 to 2° Twaddell ; wash and work for an hour in 5 lbs. peachwood at hand- 
 heat ; raise with alum ; wash and finish. 
 
 270. Blue and Orange. 
 
 First dye the cotton a blue by the blue vat, No. 39; wash, and then 
 dye the wmollen by working one hour in 2 lbs. tartar, 8 oz. cochineal, 2 lbs. 
 fustic, and 2 pints bichloride of tin, No. 27 ; wash from this and dry. 
 
 In this way almost any two colours may be dyed upon cotton and 
 woollen, although woven together, by proceeding as the receipt for the 
 colour required on each sort of fibre ; and except as in the case where cotton 
 is dyed by the blue vat, and consequently fast, the woollen is always to be 
 dyed first. The same rule is applicable to silk and woollen. The two 
 
MIXED FABRICS. 
 
 409 
 
 have to be dyed separately, although in many cases the silk takes on more 
 dye during the dyeing of the woollen than cotton does. 
 
 A mixture of silk and cotton when required two colours, has also to 
 be done in the same manner ; but it is much more difficult, and cannot be 
 done with every kind of colour ; it is a process, however, seldom required. 
 
 These processes are more in use for re-dyes, as generally in mixed 
 fabrics the different stuffs are dyed in the hank before being woven. 
 
MIXED FABRICS. 
 
 DYED ONE COLOUR. 
 
 Should tlie mixed fabrics be required all of one colour, the same double 
 process has often to be adopted, especially when the fabrics are cotton and 
 woollen ; as, for instance — 
 
 271. Black on Cotton and Woollen. 
 
 The woollen is dyed first, as No. 211, and then, to dye the cotton, the 
 goods are laid in sumach, and dyed as No. 72; and so on for any colour of 
 these mixed fabrics. 
 
 272. Brown on Cotton and Woollen by one Process. 
 
 Work the goods for two hours in catechu, same as No. 81 ; then work 
 for an hour at boiling heat with 8 oz. chrome and 2 oz. tartar ; lift out and 
 work an hour in 2 lbs. fustic and 8 oz. cudbear; wash and dry. Should a 
 deeper shade be required, or a shade more to the chocolate hue, add with 
 the cudbear 4 oz. logwood. 
 
 273. Black on Silk and Woollen by one Process. 
 
 Work an hour in a solution of 8 oz. tartar, and 8 oz. copperas, and 
 wash out ; work for fifteen minutes in a decoction of 4 lbs. logwood ; lift, 
 and add 1 oz. bichromate of potash ; work half an hour and dry. 
 
 274. Black on Cotton, Silk, and Woollen, by one Process. 
 
 Steep for six hours in 2 lbs. sumach, then work for an hour in a 
 solution of 6 oz. tartar, 6 oz. bluestone, and 6 oz. copperas ; wash from this, 
 and work half an hour in a decoction of 4 lbs. logwood ; lift and raise 
 with 1 oz. copperas ; work ten minutes ; wash and dry. 
 
 Should a very deep black be required, add 1 lb. of bark with the 
 logwood; all else the same. 
 
 275. Drabs on Cotton, Silk, and Woollen, by one Process. 
 
 Work the goods half an hour in 8 oz. sulphate of iron and 4 oz. 
 tartar; lift and drain; then work for half an hour in 4 oz. logwood and 
 .1 oz. chrome ; wash out and dry. 
 
COLOUR AND DRESS. 
 
 411 
 
 By varying the quantity of these stuffs, or by using a little fustic or 
 peachwood in the last bath, a great variety of shades of drab, slates, or 
 fawns may be produced, the different fibres being equally dyed. 
 
 The operator, by a careful study of the different modes of dyeing the 
 different fabrics, may easily dye any mixed fabric one or more colours, 
 always bearing in mind that nothing be used to affect the fibre of any one 
 of the mixtures ; particularly in attempting to remove the colour from a 
 mixed fabric, be careful not to use substances that affect the silk or 
 woollen, such for example as bleaching liquor, caustic alkalies, or lime. 
 
 Colour and Dress. 
 
 The following remarks upon the harmony of colours, taken from 
 M. E. Chevreul, may prove of some value in selecting colours. 
 
 “ Red Drapery. — Rose-red cannot be put in contact with the rosiest 
 complexions without causing them to lose some of their freshness. Dark 
 red is less objectionable for certain complexions than rose-red, because, 
 being higher than this latter, it tends to impart whiteness to them in con- 
 sequence of contrast of tone. 
 
 “ Green Drapery . — A delicate green is, on the contrary, favourable to 
 all fair complexions which are deficient in rose, and which may have more 
 imparted to them without inconvenience ; but it is not so favourable to 
 complexions that are more red than rosy, nor to those that have a tint of 
 orange mixed with brown, because the red they add to this tint will be of 
 a brick-red hue. In the latter case a dark green will be less objectionable 
 than a delicate green. 
 
 “ Yellow Drapery .— Yellow imparts violet to a fair skin, and in this 
 view it is less favourable than delicate green. To those skins which are 
 more yellow than orange it imparts white ; but this combination is very 
 dull and heavy for a fair complexion. When the skin is tinted more with 
 orange than yellow, we can make it roseate by neutralising the yellow ; it 
 produces this effect upon the black-haired type, and it is thus that it suits 
 brunettes. 
 
 “ Violet Draperies. — Violet, the complementary of yellow, produces 
 contrary effects; thus, it imparts some greenish yellow to fair com- 
 plexions ; it augments the yellow tint of yellow and orange skins. The 
 little blue there may be in a complexion it makes green. Violet, then, is 
 one of the least favourable colours to the skin, at least when it is not 
 sufficiently deep to whiten it by contrast of tone. 
 
 “ Blue Drapery . — Blue imparts orange, which is susceptible of allying 
 itself favourably to white and the light flesh tints of fair complexions, 
 which have already a more or less determined tint of this colour. Blue is, 
 
412 
 
 COLOUR AND DRESS. 
 
 then, suitable to most blondes, and in this case justifies its reputation. 
 It will not suit brunettes, since they have already too much of orange. 
 
 “ Orange Drapery . — Orange is too brilliant to be elegant ; it makes 
 fair complexions blue, whitens those which have an orange tint, and gives 
 a green hue to those of a yellow tint. 
 
 “ White Drapery . — Drapery of a lustreless white, such as cambric, 
 muslin, assorts well with a fresh complexion, of which it relieves the rose 
 colour ; but it is unsuitable to complexions which have a disagreeable tint, 
 because white always exalts all colours by raising their tone ; consequently, 
 it is unsuitable to those skins which, without having this disagreeable tint, 
 very nearly approach it. Very light white draperies, such as muslin, 
 plaited or point lace, have an entirely different aspect. 
 
 “ Black Drapery . — Black draperies, answering the tone of the colours 
 with which they are in juxtaposition, whiten the skin ; but if the vermilion 
 or rosy parts are to a certain point distant from the drapery, it will follow 
 that, although lowered in tone, they appear relatively to the white parts of 
 the skin contiguous to this same drapery redder than if the contiguity 
 to the black did not exist.” 
 
GLOSSARY OF TECHNICAL TERMS 
 
 USED IN THE DYE-HOUSE, 
 
 WITH THE CHEMICAL NAMES, 
 
 A FULL EXPLANATION OF WHICH MAY BE OBTAINED IN THE VOLUME. 
 
 Adjective. A term applied to a colour depending on a base for its production. 
 Aquafortis. Nitric acid. 
 
 Aqua-regia. A mixture of hydrochloric and nitric acids, generally in the 
 proportion of two of the former to one of the latter. 
 
 Alkali root. Alkanet root. 
 
 Alterant. A substance added to the colouring liquor to give it brightness, 
 same as “ raising.” 
 
 Argol. Bitartrate of potash, formed by deposit on wine casks. 
 
 Arnotto. Annotta. 
 
 Barilla. The name of an impure soda imported from Spain and the Levant. 
 Black ash. Carbonate of potash in fused masses, as imported. 
 
 Black lead. Plumbago. Impure carbon. 
 
 Black iron liquor. Acetate of iron, or pyrolignite of iron. 
 
 Bleed. To extract the colouring matter from a dye-drug. 
 
 Bleaching powder. Chloride of lime. 
 
 Block tin. Commercial tin cast into ingots or blocks, not so pure as grain tin. 
 Borax. Borate of soda. 
 
 Blue copperas. Sulphate of copper. 
 
 Blue-stone. Sulphate of copper. 
 
 Blue vitriol. Sulphate of copper. 
 
 Bottom. Applied to the base of a colour, such as sumach, galls, &c. 
 Brimstone. Sulphur. 
 
 Brown sugar. Acetate of lead, or pyrolignite of lead. 
 
 Bucking. Boiling goods in an alkaline ley. 
 
 Bundle. Ten pounds of cotton yarn. 
 
 Calomel. Protochloride of mercury. 
 
 Carmine. Colouring matter of cochineal, extracted and dried. 
 
 Chamber -ley . Urine. 
 
 Chemic, or chemic blue. Sulphate of indigo. 
 
 Chrome. Bichromate of potash. 
 
 Common salt. Chloride of sodium. 
 
 Copperas. Protosulphate of iron. 
 
414 
 
 GLOSSARY. 
 
 Corrosive sublimate. Bichloride of mercury. 
 
 Cream of tartar. Bitartrate of potash, purified. See Argol. 
 
 Crofting. Exposing goods upon the grass. 
 
 Crude tartar. See Argol. 
 
 Crystals of tin. Chloride of tin. 
 
 Dip. Generally applied to immersing goods in the blue vat. 
 
 Doctored. To adulterate, generally applied to giving an appearance of strong 
 colour to dyewoods, by adding water containing lime to them. 
 
 Double muriate of tin. A saturated solution of bichloride of tin. 
 
 Epsom salts. Sulphate of magnesia. 
 
 Essential salt of lemons. Binoxalate of potash. 
 
 Extract of indigo. Sulphate of indigo. 
 
 Fast colour. Permanent colours. 
 
 Fancy colour. Colours subject to fade ; fugitive. 
 
 Feathering. To granulate a metal. 
 
 Firing spirits. When tin by dissolving too rapidly, or by heat, Becomes con- 
 verted into a bichloride. 
 
 Flake. A wooden frame on which wet goods are placed to drain. 
 
 Fluery of a vat. The froth of oxidised indigo floating on the surface of a 
 blue vat. 
 
 Flowers of zinc. Oxide of zinc. 
 
 French tub. Protochloride of tin and logwood, plumb tub. 
 
 Glauber salts. Sulphate of soda. 
 
 Grain tin. Metallic tin in prismatic pieces. 
 
 Green vitriol. Sulphate of iron, copperas. 
 
 Hartshorn. Ammonia. 
 
 Kelp. Ashes left on burning sea- weed. 
 
 Killing. Dissolving any substance in an acid, as iron in nitric acid ; killing 
 iron. 
 
 King's yellow. Sulphuret of arsenic. 
 
 Lactine. Curd of milk used for animalising cotton. 
 
 Lemon juice. Citric acid. 
 
 Ley. Solution of an alkali, as potash or soda. 
 
 Lime juice. Citric acid. 
 
 Lime shell. Caustic lime. 
 
 Lime stone. Unburned or carbonate of lime. 
 
 Litharge. Protoxide of lead. 
 
 Lunar caustic. Nitrate of silver. 
 
 Magnesia nigra. Manganese. 
 
 Marine acid. Hydrochloric acid. 
 
 Mineral alkali. Soda. 
 
 Mordant. Generally applied only to acetate of alumina. 
 
 Muriatic acid. Hydrochloric acid. 
 
 Muriates. Chlorides. 
 
 Nitromuriate of tin. A solution of tin in nitric and hydrochloric acids, 
 forming a persalt. 
 
GLOSSARY. 
 
 Nitre. Nitrate of potash. 
 
 Oxy muriate of tin. Perchloride of tin. 
 
 Oxymuriate of potash. Chlorate of potash. 
 
 Oxymuriatic acid. Chlorine. 
 
 Oil of vitriol. Sulphuric acid. 
 
 Orpiment. Persulphide of arsenic. 
 
 Oxy yen of the bleachers. Chlorine, chloride of lime, bleaching powder. 
 Pearlash. Carbonate of potash. 
 
 Permuriate of tin. Perchloride of tin. 
 
 Prussiate of potash. Ferrocyanide of potassium. 
 
 Queen-wood. Brazil-wood. 
 
 Quicksilver. Mercury. 
 
 Raising. See Alterant. 
 
 Realgar. Sulphide of arsenic. 
 
 Red chrome. Bichrome of potash. 
 
 Red liquor. Acetate of alumina. 
 
 Rot steep. Steeping cloth in old leys to soften the paste ; fermentation takes 
 place, hence the name. 
 
 Roman vitriol. Sulphate of copper. 
 
 Saddening. Making a colour darker by means of a salt of iron. 
 Sal-ammoniac. Chloride of ammonium. 
 
 Sali nixon. Bisulphate of potash. 
 
 Sal prunella. Fused nitrate of potash cast into balls or cakes. 
 
 Sal volatile. Sesquicarbonate of ammonia. 
 
 Salt of lemons. Citric acid. 
 
 Salt of saturn. Acetate of lead. 
 
 Salt of soda. Carbonate of soda. 
 
 Salt of sorrel. Binoxalate of potash. 
 
 Salt of tartar. Carbonate of potash. 
 
 Salt of vitriol. Sulphate of zinc. 
 
 Salt perlate. Phosphate of soda. 
 
 Saltpetre. Nitrate of potash. 
 
 Salt sedative. Boracic acid. 
 
 Salts of tin. Crystallised protochloride of tin. 
 
 Salt cake. Sulphate of soda. 
 
 Saxon blue. Sulphate of indigo. 
 
 Scalding. Extracting a colouring matter by boiling water. 
 
 Smalt blue. Ground glass, made of alumina, silica, potash, or soda, coloured 
 blue by oxide of cobalt. 
 
 Slaked lime. Hydrate of lime. 
 
 Sludge. Sediment of the blue vat. 
 
 Single muriate of tin. Half strength of double perchloride of tin. 
 
 Sour. Water made acid by sulphuric or muriatic acid. 
 
 Soda ash. Carbonate of soda not crystallised. 
 
 Spirits. Solutions of chlorides of tin. 
 
 Spirits of salt. Hydrochloric acid. 
 
416 
 
 GLOSSARY. 
 
 Spirits of hartshorn. Ammonia. 
 
 Spirits of wine. Alcohol. 
 
 Spent. Exhausted of colour. 
 
 Storing. Hanging goods in the stove to dry. 
 
 Stock tub. Vessel filled with strong solution of a substance to be kept for 
 use. 
 
 Sugar of lead. Acetate of lead. 
 
 Substantive colour. A colour fixed in the fibre without mordant — not a 
 compound. 
 
 Supertartrate of potash. See Argol. 
 
 Sweeten. To pour water upon goods from a sour placed on a frame, as a 
 partial wash. 
 
 Tartar. See Argol. 
 
 Test blue. Sulphate of indigo. 
 
 Tincal. Borate of soda, borax. 
 
 Turnbull's blue. Ferrocyanide of iron, Prussian blue. 
 
 Vegetable alkali. Potash. 
 
 Verdigris. Acetate of copper. 
 
 Verditer. Acetate of copper. 
 
 Vinegar. Acetic acid. 
 
 Vitriol. Sulphuric acid. 
 
 Volatile alkali. Ammonia. 
 
 Vomiter. A boiler so constructed that the boiling liquid is thrown up a pipe 
 and showered on the goods. 
 
 White vitriol. Sulphate of zinc. 
 
 White copperas. Sulphate of zinc. 
 
 White lead. Carbonate of lead. 
 
 Whiting. Carbonate of lime. 
 
 White zinc. Oxide of zinc. 
 
INDEX 
 
 Absorption of gases by water, 38. 
 
 Acetate of alumina, 121, 199, 350. 
 
 ,, of barytes, 115. 
 
 ,, of copper — verdigris, 146. 
 
 ,, of iron— iron liquor, 135. 
 
 Acid, arsenic and arsenious, 173. 
 
 ,, bromic, 84. 
 
 „ carbonic, 88. 
 
 ,, chloric and chlorous, 50. 
 
 ,, gallic, 213. 
 
 „ hydrochloric, 51. 
 
 „ hypobromic and hypobromous, 84. 
 
 ,, hypochlorous and hypochloric, 50. 
 
 ,, liypophosphorous, 83. 
 
 ,, hyposulphuric, 81. 
 
 ,, hyposulphurous, 80. 
 
 ,, hydriodic, 84. 
 
 „ nitric, 42. 
 
 , , oxalic, 88. 
 
 ,, perchloric, 51. 
 
 „ phosphoric and phosphorous, 83. 
 
 ,, sulphurous, 73. 
 
 ,, sulphuric, 74. 
 
 Affinity, 23. 
 
 Ammonia, 48. 
 
 Analine, 328. 
 
 ,, black, 332. 
 
 Alizarin, 333. 
 
 „ its nature and composition, 331. 
 
 Alkalimetry, 105. 
 
 Alkanet root, 306. 
 
 Aloes, 315. 
 
 Alum, 117. 
 
 Alumina, 117. 
 
 Annotta or arnotta, 303. 
 
 „ preparation, 347. 
 
 „ dyeing with, 304. 
 
 Anthrapurpurin, 336. 
 
 Antimony, 175. 
 
 Application of laws of affinity, 24. 
 
 ,, of the effects of heat, 73. 
 
 Aquafortis, 42. 
 
 Archil, products from, 307. 
 
 Arrangement of colours, 14. 
 
 Arsenic, 172. 
 
 „ green, how dyed, 173. 
 
 Barium, 115. 
 
 Barbary root, 317. 
 
 Bark or quercitron, 285. 
 
 Barium chloride, 115. 
 
 Barwood, 280. 
 
 Bismuth and its salts, 151. 
 
 Blacks on cotton, 357. 
 
 „ on silk, 379. 
 
 „ on woollen, 395. 
 
 2 D 
 
 Bleaching, old method of, 56. 
 
 „ theory of, 57, 69. 
 
 „ solutions, how prepared, 64. 
 
 „ cotton for dyeing, 340. 
 
 Bleu de Paris, 331. 
 
 Blue vat for cotton, 346. 
 
 „ setting of for cotton, 256. 
 
 „ theory of, 253. 
 
 „ stone, 145. 
 
 Blues on cotton, 367. 
 
 ,, on silk, 386. 
 
 ,, on woollen, 400. 
 
 Boiling of liquids, 5. 
 
 Borate of soda, 109. 
 
 Borax, 86. 
 
 Boron, 85. 
 
 Brazil-woods, 276. 
 
 Bromine, 84. 
 
 Browns on cotton, 358. 
 
 ,, on silk, 381. 
 
 ,, on woollen, 396. 
 
 Cadmium, 143. 
 
 „ salts, 143. 
 
 Calcium, 116. 
 
 Camwood, 282. 
 
 Carajura or Chica, 311. 
 
 Carbon, 86. 
 
 Carbonic oxide, 87. 
 
 „ acid, 88. 
 
 Carthamus, 290. 
 
 Catalysis, 25. 
 
 Catechu, 347, 224. 
 
 Caustic potash and soda, how made, 341. 
 
 Cerium, 178. 
 
 Chemic, 349. 
 
 Chestnut, 228. 
 
 Chlorine, its properties, on, 49. 
 
 „ combined with oxygen, 50. 
 
 Chloride of lime, bleaching powder, 59. 
 
 „ table of values, 64. 
 
 „ how tested, 61. 
 
 „ of nitrogen, 55. 
 
 „ of sodium, 109. 
 
 Chlorate of potash, 96. 
 
 Chromium, 162. 
 
 Chromic acid, 164. 
 
 Chrome greens, 168. 
 
 „ orange, 168. 
 
 „ yellows, 166. 
 
 Coal-tar colours, 325. 
 
 ,, their history, 326. 
 
 Cobalt, 139. 
 
 Cochineal, 318. 
 
 its composition and properties, 319. 
 dye, remarks on, 384. 
 
418 
 
 INDEX. 
 
 Colour of flowers, 211. 
 
 Colouring matter of logwood, 270. 
 
 „ matters absorbed by carbon, 87. 
 
 Colours for dress, choosing of, 411. 
 
 Copperas, 130. 
 
 „ how made, 343. 
 
 Copper and salts of, 144. 
 
 ,, nitrate, 342. 
 
 ,, sulphate, 343. 
 
 Corrosive sublimate, 178. 
 
 Cotton dyeing, 356. 
 
 Cyanogen, 89. 
 
 Cyanide of potassium, 101. 
 
 Decoctions of woods, how made, 347. 
 
 Divi divi, 227. 
 
 Drab colours on cotton, 377. 
 
 „ on silk, 391. 
 
 ,, on woollen, 406. 
 
 Dyed colours, how detected, 353. 
 
 Dyeing receipts, 338. 
 
 Effects of heat on colours, 6. 
 
 „ of light on colours, 10. 
 
 „ of light on combination, 11. 
 
 „ of light on decomposition, 12. 
 
 Elements, what they are, 16. 
 
 „ table of, 16. 
 
 Equivalents in volume, 17. 
 
 Erbium, 185. 
 
 Fawn colours on cotton, 361. 
 
 Flavine, 287. 
 
 Fluorine, 85. 
 
 Fustic or yellow wood, 283. 
 
 Galls, 213. 
 
 ,, analysis of, 219. 
 
 Garancine, 301. 
 
 „ action of re-agents on, 302. 
 
 Gases absorbed by carbon, 86. 
 
 German blue vat, 264. 
 
 Gold and its salts, 181. 
 
 Glossary of terms, 413. 
 
 Green, aldehyd, 331. 
 
 ,, colouring matter on vegetables, 209. 
 
 Greens on cotton, 370. 
 
 „ on silks, 393. 
 
 „ on woollen, 402. 
 
 Hartshorn, 48. 
 
 Heat the cause of conditions of matter, 1. 
 
 „ its effects on matter, 2 . 
 
 ,, by mixing vitriol and water, 78. 
 
 Hydrocarbons, 90. 
 
 Hydrogen, 31. 
 
 ,, binoxide, 39. 
 
 Incrustation on steam boilers, 38. 
 
 Indigo, 230. 
 
 „ theory of its formation, 234. 
 
 ,, its composition, 234, 244. 
 
 „ extracts, 251, 348. 
 
 ,, testing quality of, 235. 
 
 „ different qualities, 242. 
 
 „ relations to other compounds, 249. 
 „ sulphate, 250. 
 
 „ blue vat, 252. 
 
 Indian blue vat, 263. 
 
 Indium, 143. 
 
 Ink, indelible marks removed, 351. 
 Introduction to dyeing receipts, 338. 
 
 Iodine, 83. 
 
 Iridium, 184. 
 
 Iron, 129. 
 
 Iron liquor, 134. 
 
 „ oxides of, as mordants, 190. 
 
 „ its salts, in dyeing, 134. 
 
 „ nitrate, 198. 
 
 „ sulphate, copperas, 130. 
 
 „ stains removed, 340. 
 
 Iverms, 323. 
 
 Lac dye, 322. 
 
 Lanthanium, 185. 
 
 Lavenders and lilacs on cotton, 373. 
 
 Lead, 146. 
 
 Lead salts, 147. 
 
 Light, theory of, 8. 
 
 Lithium, 110. 
 
 Litharge, 147. 
 
 Lime, 116. 
 
 ,, sulphate, 116. 
 
 ,, carbonate, 117. 
 
 Logwood, 269. 
 
 „ action of salts upon, 272. 
 
 „ testing of, 274. 
 
 Madder, 294. 
 
 „ acids, 299. 
 
 ,, purple, 298. 
 
 ,, dutch, 295. 
 
 „ orange, 299. 
 
 „ red, 298. 
 
 „ yellow, 299. 
 
 „ brown, 299. 
 
 „ of Avignon, 295. 
 
 „ Levant, 294. 
 
 ,, useful products of, 299. 
 
 „ preparations, 300. 
 
 Magenta, 329. 
 
 Magnesia, 117. 
 
 Manganese, 127. 
 
 ,, compounds, 128. # 
 
 Matter, general properties and conditions 
 of, 1. 
 
 Mauve dye, 327. 
 
 Mercury, 178. 
 
 Metals, their general properties, 91. 
 
 Mildew, how removed, 351. 
 
 Mixed fabrics, how tested, 351. 
 
 ,, how dyed, 408. 
 
 ,, dyed two colours, 408. 
 
 ,, dyed one colour, 410. 
 
 Molybdenum, 171. 
 
 „ compound, 171. 
 
 Mordants, 186. 
 
 ,, their action, 187. 
 
 ,, the theory of, 201. 
 
 Munjeet or mungeet, 303. 
 
 Muriate of iron, 343. 
 
 Myrobalans, 227. 
 
 Naming substances, rules for, 20. 
 
 Nature of salts, 21. ' 
 
INDEX. 
 
 419 
 
 Nickel, 140. 
 
 n salts, 140. 
 
 Niobium, 185. 
 
 Nitric acid, 42. 
 
 Nitrate of iron, how made, 342. 
 
 m of barytes, 115. 
 
 Nitrogen, 39. 
 
 ii with oxygen, 40. 
 
 Nomenclature, 20. 
 
 Oak bark, 227. 
 
 Oil stains removed, 340. 
 
 Oranges on cotton, 306. 
 
 Orpiment, 174. 
 
 Osmium, 184. 
 
 Oxygen, 29. 
 
 ti how made, 29. 
 
 Oxalic acid, 88. 
 
 Oxalate of potash, 97. 
 
 Oxides of lead, 147. 
 
 Ozone, 71. 
 
 Pastel vat, 259. 
 
 Paladium, 183. 
 
 Peach-wood, 277. 
 
 Pearlash, 93. 
 
 Persian berries, 289. 
 
 Phosphorus, 82. 
 
 Phosphate of potash, 97. 
 
 it of soda, 109. 
 
 Pink and reds on cotton, 361. 
 it on silk, 382. 
 
 ii on woollen, 397. 
 
 Platinum, 182. 
 
 ii salts of, 183. 
 
 Picric acid, 247. 
 
 Pittacal, 316. 
 
 Plumb tub, 275. 
 
 ii tubs, 346. 
 
 Potash, 92. 
 
 ii nitrate, 96. 
 ii sulphate, 96. 
 ti bisulphate, 96. 1 
 n cyanate, 101. 
 ti vat, 264. 
 
 Potassium, 91. 
 
 n ferrocyanide, 97. 
 
 ii cyanide, 101. 
 
 Preparing goods for dyeing, 339. 
 Preparation of cotton for dyeing, 356. 
 Printing resists, 248. 
 
 Prussian blue for domestic use, 353. 
 Purples, puces, &c., on silk, 388. 
 
 ii on woollen, 405. 
 
 ii on cotton, 373. 
 
 Realgar, 174. 
 
 Red prussiate of potash, 100. 
 
 ii colours on woollen, 397. 
 
 Rhodium, 184. 
 
 Rosaniline, 330. 
 
 Royal blue removed from silk and woollen, 
 352. 
 
 Ruthenium, 185. 
 
 Safflower or Carthamus, 290. 
 
 „ how prepared, 349. 
 
 Santal or Saunders- wood, 279. 
 
 Salts, their constitution, 21. 
 n of chromium, 165. 
 
 Salt radicals, 27. 
 
 Scarlet dye removed, 353. 
 
 Selenium, 82. 
 
 Silicium, 85. 
 
 Silk, composition of, 193. 
 
 „ dyeing, 379. 
 
 Silver, 179. 
 
 ,, salts of, 180. 
 
 Slaked lime, 342. 
 
 Soaps, 111. 
 
 Sodium, 101. 
 
 Soda manufacture, 102. 
 n testing strength of, 106. 
 ii nitrate and sulphate, 109. 
 
 Sooranjee, 308. 
 
 Sours, how made, 342. 
 
 Stannate of soda, 160. 
 
 Straw, colours on cotton, 364. 
 
 Strong boiling, 5. 
 
 Strontium, 115. 
 
 Substances affecting boiling point, 5. 
 
 Sugar of lead, 148. 
 
 Sulphur, 72. 
 
 ii and oxygen, 73. 
 
 Sulphate of alumina, 121. 
 
 Sulphide of hydrogen, 81. 
 
 Sulphite of potash, 96. 
 
 Sumach, 220. 
 
 Spirit mordants, 196. 
 
 Spirits, tin, 158. 
 
 n different, how made, 345. 
 
 Symbols, use of, 19. 
 
 Table of Centigrade and Fahr. scale, 4. 
 ii of solubility of different salts, 37. 
 ii of strength of nitric acid, 46. 
 
 ,, of strength of hydrochloric acid, 53. 
 ii of strength of sulphuric acid, 79. 
 ii of test by mixing vitriol & water, 78. 
 ii of boiling points and gravity of 
 potash in solution, 95. 
 ii of soda in solution of different 
 gravities, 108. 
 
 it of action of salts on galls and 
 sumach, 217. 
 
 Tannin, 214. 
 
 it into gallic acid, 216. 
 
 n quantitative testing, in any vege- 
 
 table, 353. 
 
 Tellurium, 172. 
 
 Temperature, measures of, 3. 
 
 Testing nitric acid, 45. 
 ii dyed colours, 354. 
 
 ,i tin salts, 157. 
 
 i, lead salts, 151. 
 
 Thallium, 151. 
 
 Tin, 152. 
 
 Tin salts, &c., 154, 341. 
 
 ti double and single muriates, 157. 
 
 Titanium, 162. 
 
 Turmeric, 289. 
 
 Tungstenum, 170. 
 
 Ultramarine, 323. 
 
 Uranium, 176. 
 
 i, oxides and salts, 177. 
 
420 
 
 INDEX. 
 
 Valonia, 227. 
 
 Vanadium, 170. 
 
 Vats, management of, 265. 
 
 n made up with zinc, 268. 
 
 Vegetable matters used in dyeing, 206. 
 
 it ii their composition, 207. 
 Verdigris, 146. 
 
 Violets, Hofmann’s, 331. 
 
 n on cotton, 373. 
 
 ii on silk, 389. 
 
 i, on woollen, 404. 
 
 Vitriol, testing for impurities, 80. 
 
 Water, 32. 
 
 it how tested, 34 350. 
 
 Weld or wold, 288. 
 
 Woad vat, 261. 
 
 Woad and pastel, 257. 
 Wongshy, 312. 
 
 Wools, composition of, 193. 
 Woollen dyeing, 395. 
 Woolfram, 170. 
 
 Yellow prussiate of potash, 
 n on cotton, 364. 
 
 „ on silk, 389. 
 
 ,t on woollen, 399. 
 
 Young, J., improvements in 
 103. 
 
 i, fustic, 284. 
 
 Zinc, 141. 
 ii salts, 142. 
 i, sulphate, 344. 
 
 THE END. 
 
 97 . 
 
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 DALLAS (W. S., F.L.S.) : 
 
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 DOUGLAS (John Christie, Mem. Soc. Tel. Eng., 
 
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 * A MANUAL OF TELEGRAPH CONSTRUCTION. For the use 
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 # A MANUAL OF THE ART OF DYEING AND DYEING 
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 A MANUAL OF ELECTRO-METAL- 
 
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 PHILLIPS (John, M.A., F.R.S., late Professor 
 of Geology in the University of Oxford) : 
 
 # A MANUAL OF GEOLOGY : Theoretical and Practical. Edited 
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14 
 
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 PHILLIPS (J. Arthur, M. Inst. C.E.,F.C.S.,F.G.S., 
 
 Ancien Eleve de l’Ecole des Mines, Paris) : 
 
 * ELEMENTS OF METALLURGY : a Practical Treatise on the Art 
 of Extractine Metals from their Ores. With over 200 Illustrations, many 
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 General Contents. 
 
 I —A Treatise on Fuels and Refractory Materials. 
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 SCIENTIFIC MANUALS 
 
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 *1. RANKINE (Prof.): APPLIED MECHANICS: 
 
 comprising the Principles of Statics and Cinematics, and Theory of Struc- 
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 TEXT-BOOK, by Prof. Macquorn Rankine and E. F. Bamber, 
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 Prof. Rankine’s Works —[ continued ). 
 
 # VII. RANKINE (Prof.): MISCELLANEOUS 
 
 SCIENTIFIC PAPERS, from the Transactions and Proceedings of the 
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 ^ A MANUAL OF MARINE ENGINEERING ; Comprising the 
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 ^COLERIDGE (Samuel Taylor): A DISSER- 
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 CRAIK’S ENGLISH LITERATURE. 
 
 *A COMPENDIOUS HISTORY OF 
 
 ENGLISH LITERATURE AND OF THE ENGLISH LANGUAGE 
 FROM THE NORMAN CONQUEST. With numerous Specimens. 
 By George Lillie Craik, LL.D., late Professor of History and 
 English Literature, Queen’s College, Belfast. New Edition. In two 
 vols. Royal 8vo. Handsomely bound in cloth, ..... 
 
 GENERAL CONTENTS. 
 
 Introductory. 
 
 I. — The Norman Period — The Conquest. 
 
 II. — Second English— Commonly called Semi-Saxon. 
 
 III. — Third English — Mixed, or Compound English. 
 
 IV. — Middle and Latter Part of the Seventeenth Century. 
 
 V. — The Century between the English Revolution and 
 
 the French Revolution. 
 
 VI. — The Latter Part of the Eighteenth Century. 
 
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 {l>) The Victorian Age. 
 
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20 
 
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24 
 
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 trust, be extensively useful.” — Rev. Canon Liddon, D.D., D.C.L. 
 
 “ Many a busy Christian teacher will be thankful to Mr. Southgate for having unearthed! 
 so many rich gems of thought ; while many outside the ministerial circle will obtain stimulus,, 
 encouragement, consolation, and counsel, within the pages of this handsome volume.” — ■ 
 Nonconformist. 
 
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 often brilliant lights shed by passages selected from the best authors in all ages. ... A 
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 selections it contains, the book is of value as an index to theological writings. As a model oT 
 judicious, logical, and suggestive treatment of a subject, we may refer our readers to the- 
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 Thoughts.’ ” — Glasgow News. 
 
CHARLES GRIFFIN <t CO:S GENERAL PUBLICATIONS. 
 
 THE SHILLING MANUALS. 
 
 By JOHN TIMBS, F.S.A., 
 
 Author of “The Curiosities of London,” &c. 
 
 A Series of Hand-Books, containing Facts and Anecdotes interesting to 
 all Readers. Second Edition . Fcap 8vo. Bound in neat cloth. 
 
 I.— TIMBS’ CHARACTERISTICS OF EMINENT MEN, . 
 
 II.— TIMBS’ CURIOSITIES OF ANIMAL AND VEGETABLE 
 LIFE, 
 
 III. — TIMBS’ ODDITIES OF HISTORY AND STRANGE STORIES 
 
 FOR ALL CLASSES, 
 
 IV. — TIMBS’ ONE THOUSAND DOMESTIC HINTS on the Choice 
 
 of Provisions, Cookery, and Housekeeping ; new Inventions and 
 Improvements ; and various branches of Household Management, . 
 
 V. — TIMBS’ POPULAR SCIENCE : Recent Researches on the Sun, 
 Moon, Stars, and Meteors ; the Earth ; Phenomena of Life, 
 Sight, and Sound ; Inventions and Discoveries, .... 
 
 VI. — TIMES’ THOUGHTS FOR TIMES AND SEASONS, 
 
 Opinions of the Press on the Series. 
 
 “ It is difficult to determine which of these volumes is the most attractive. Will be 
 found equally enjoyable on a railway journey or by the fireside .”— Mining Journal. 
 
 “These additions to the Library, produced by Mr. Timbs’ industry and ability, are 
 useful, and in his pages many a hint and suggestion, and many a fact of importance is 
 stored up that would otherwise have been lost to the public.”— Builder. 
 
 “ Capital little books of about a hundred pages each, wherein the indefatigable 
 Author is seen at his best.’”— Mechanic's Magazine. 
 
 “ Extremely interesting volumes .” — Evening Standard. 
 
 “Amusing, instructive, and interesting. ... As food for thought and pleasant 
 reading, we can heartily recommend the ‘Shilling Manuals .’ -Birmingham Daily 
 Gazette. 
 
 TIMBS (John, F.S.A.) : PLEASANT HALF- 
 
 HOURS FOR THE FAMILY CIRCLE. Containing Popular Science, 
 One Thousand Domestic Hints, Thoughts for Times and Seasons, 
 Oddities of History, and Characteristics of Great Men. Second Edition. 
 Fcap 8vo. Cloth gilt, and gilt edges, . . 
 
 “Contains a wealth of useful reading of the greatest possible variety .” — Plymouth 
 Mercury. 
 
 WANDERINGS IN EVERY CLIME; Or, 
 
 Voyages, Travels, and Adventures All Round the World. Edited by W. 
 F. Ainsworth, P.R.G.S., F.S.A., &c., and embellished with upwards 
 of Two Hundred Illustrations by the first Artists, including several from 
 the master-pencil of Gustave Dore. Demy 4to. 800 pages. Cloth 
 and gold, bevelled boards, 
 
INDEX, 
 
 AINSWORTH (W. F.), Earth Delineated 
 
 Wanderings in Every Clime, . 
 
 AITKEN (W., M.D.), Science and Practice of 
 
 Medicine, 
 
 — Outlines, . 
 
 ■ Growth of the Recruit, 
 
 ANSTED (Prof.), Geology, 
 
 Inanimate Creation, 
 
 BAIRD (Prof.), Student’s Natural History 
 BELL (R.), Golden Leaves, 
 
 BLYTH (A. W.), Hygiene and Public Health 
 Foods, 
 
 Poisons, 
 
 B ROUGH AM (Lord), Paley’s N atural Theology, 
 BROWNE (W. R.), Student’s Mechanics, 
 
 Foundations of Mechanics, 
 
 BRYCE (A. H.), Works of Virgil, . 
 
 Works of Virgil (in Parts), 
 
 BUNYAN'S Pilgrim’s Progress (Mason), 
 
 ~T 7T - 7~ I)o - (Maguire), 
 
 Select Works, .... 
 
 CHEEVER’S (Dr.), Religious and Moral 
 
 Anecdotes, 
 
 CHRISTISON (J.), Interest Tables, 
 
 CIRCLE OF THE SCIENCES, 9 vols., 
 
 Treatises, 
 
 COBBETT (Wm.), Advice to Young Men, 
 
 Cottage Economy, .... 
 
 English Grammar, .... 
 
 French do., . . . ! 
 
 Legacy to Labourers, . . * 
 
 Do. Parsons, .... 
 
 COBBIN’S Mangnall’s Question, 
 
 COLERIDGE on Method, . . 
 
 COOK (Captain), Voyages of, . 
 
 CRAIK (G.), History ot English Literature, 
 
 Manual of do. 
 
 CRUDEN’S CONCORDANCE, by Eadie, 
 
 by Youngman, . . . 2 
 
 CRUTTWELL S History of Roman Literature, 20 
 
 Specimens of do., 
 
 Do., do. (in Parts), 
 
 CURRIE (J.), Works of Horace, . / 
 
 , Do. (in Parts), 
 
 Caesar s Commentaries, . 
 
 DALGAIRN’S COOKERY, . . . 
 
 DALLAS (Prof.), Animal Creation, . 
 D’AUBIGNE’S History of the Reformation, 
 
 DICK (Dr.), Celestial Scenery, . 
 
 Christian Philosopher, 
 
 DONALDSON (Jas.), Eventful Life of 
 
 Soldier, 
 
 D’ORSEY (A. J.), Spelling by Dictation, 
 DOUGLAS (J. C.), Manual of Telegraph Con 
 
 struction, 
 
 DUPRE and HAKE, Practical Chemistry, 
 EADIE (Rev. Dr.), Biblical Cyclopaedia, 
 
 Cruden’s Concordance, . 
 
 Classified Bible, 
 
 Ecclesiastical Cyclopaedia, 
 
 Dictionary of Bible, 
 
 ELLIS (Mrs.), Englishwoman’s Library. 
 EMERALD SERIES OF STANDARD 
 AUTHORS, ... 
 
 FINDEN’S FINE-ART WORKS* ! 
 
 FISHER’S READY-RECKONER, . 
 
 FLEMING (Prof.), Vocabulary of Philosophy 
 FOSTER (Chas.), Story of the Bible, 
 
 GEDGE (Rev. J. W.), Bible History, 
 
 GILMER (R.), nterest Tables, . , 
 
 PAGE 
 
 25 
 
 32 
 
 6 
 
 7 
 
 7 
 
 9 
 
 7 
 
 7 
 
 23 
 
 8 
 8 
 8 
 5 
 7 
 7 
 
 18 
 
 18 
 
 1 
 
 1 
 
 1 
 
 1 
 
 23 
 
 9 
 
 9 
 
 23 
 
 24 
 
 18 
 
 18 
 
 24 
 
 24 
 
 18 
 
 19 
 
 24 
 
 19 
 
 19 
 
 3 
 
 GORE (G.), Electro-deposition, ... 9 
 
 GR-iEME (Elliott), Beethoven, . . . .27 
 
 Novel with Two Heroes, . . .27 
 
 GRIFFIN (J. J.), Chemical Recreations, . 10 
 
 Do. (in Parts), 10 
 
 GURDEN (R. ), Traverse Tables, . . .11 
 
 HARRIS (Rev. Dr.), Altar of Household, . 1 
 
 HENRY (M.), Commentary on the Bible, . 2 
 
 HOGARTH, Works of, . . . . .28 
 
 JAMIESON (A.), Manual of the Steam Engine 11 
 KEBLE’S CHRISTIAN YEAR, 4 to, . . 2 
 
 Do., Fcap, . 2 
 
 KITTO (Rev. Dr.), The Holy Land, . . 4 
 
 Pictorial Sunday Book, .... 4 
 
 KNIGHT (Charles), Pictorial Gallery, . . 28 
 
 Do. Museum, . . 28 
 
 LEARED (Dr.), Imperfect Digestion, . .11 
 
 LINN (Dr.), On the Teeth, . . . .12 
 
 LONGMORE (Prof.), Sanitary Contrasts, . 12 
 M ‘BURNEY (Dr. ), Ovid’s Metamorphoses, . 21 
 MACKEY (A. G.), Lexicon of Freemasonry, . 28 
 M ‘NAB (Dr.), Manual of Botany, . . 12 
 
 MAYHEW (H.), London Labour, ... 28 
 MENTAL SCIENCE (Coleridge and Whately), 21 
 MILLER (T.), Language of Flowers, . . 20 
 
 M ILLER (W. G.), Philosophy of Law, . . 21 
 
 MOFFITT (Dr.), Instruction for Attendants on 
 
 Wounded, I2 
 
 MUNRO and JAMIESON’S Electrical 
 
 Pocket-Book, .12 
 
 NAPIER (Jas.), Dyeing and Dyeing Receipts, 13 
 
 Electro-Metallurgy, . . . .12 
 
 PHILLIPS (John), Manual of Geology, . . 1^ 
 
 PHILLIPS (J. A.), Elements of Metallurgy, . 14 
 
 POE (Edgar), Poetical Works of, . 27 
 
 POETRY OF THE YEAR, . A 
 
 PORTER (Surg.-Maj.), Surgeon’s Pocket-Book, 14 
 RAGG (Rev. T.), Creation’s Testimony, . . e 
 
 RAMSAY (Prof.), Roman Antiquities, . .21 
 
 —7 Do. Elem‘y., . . .21 
 
 Latin Prosody, 2 i 
 
 Do. Elemty., 
 
 RANKINE’S ENGINEERING WORKS, is, 16 
 RAPHAEL’S CARTOONS, . . 20 
 
 RELIGIONS OF THE WORLD, ! ' K 
 
 SCHILLER’S MAID OF ORLEANS, . 70 
 SCHOOL BOARD MANUALS, . . .22 
 
 READERS, 
 
 SCOTT (Rev. Thos.), Commentary on the Bible. 2 
 SEATON (A. E.), Marine Engineering, . . 16 
 
 SENIOR (Prof.), Political Economy, . . 22 
 
 SHAKESPERE, Bowdler’s Family, . . 30 
 
 Barry Cornwall’s, .... 50 
 
 Halliwell’s, 
 
 SHELTON (W. V.), Mechanic’s Guide, . ’. i 7 
 
 SOUTHGATE (H.), Many Thoughts of Many 
 
 Suggestive Thoughts, . . * 3I 
 
 (Mrs.), Christian Life, . . . . c 
 
 THOMSON (Dr. Spencer), Domestic Medicine, 17 
 THOMSON’S SEASONS, . . . 22 
 
 TIMBS’ (John), Shilling Manuals, . . .32 
 
 ■ Pleasant Half Hours, . . . .22, 
 
 WHATELY (Archbishop), Logic, . . .22 
 
 Rhetoric, ..... 22 
 
 WORDS AND WORKS OF OUR BLESSED 
 
 LORD, q 
 
 WYLDE (Jas.), Magic of Science, . ■ I 17 
 
 Manual of Mathematics, & , , . .2* 
 
FIRST SERIES.— THIRTY-SECOND EDITION. 
 SECOND SERIES.— SEVENTH EDITION. 
 
 MANY THOUGHTS OF MANY MINDS 
 
 A TEEASUEY OF EEFEEENCE, 
 
 Consisting of Selections from the Writings of the most Celebrated Authors 
 FIRST AND SECOND SERIES. COMPILED AND ANALYTICALLY ARRANGED * 
 
 By HENRY SOUTHGATE. 
 
 In Square 8 vo, elegantly printed on Toned Paper. 
 
 Presentation Edition, Cloth and Gold, . . 12s. 6d. each Volume. 
 
 Library Edition, Half-Bound, Roxburghe, . . 14s. ,, 
 
 Do., Morocco Antique, ... . 21s. ,, 
 
 Each Series is Complete in itself, and sold separately. 
 
 “ ‘Many Thoughts,’ &c., are evi- 
 dently the produce of years of re- 
 search. We look up any sub j ect und er 
 the sun, and are pretty sure to find 
 something that has been said— gene- 
 rally well said— upon it.” — Examiner. 
 
 “ Many beautiful examples of 
 thought and style are to be found 
 among the selections.” — Leader. 
 
 “There can be little doubt that it 
 is destined to take a high place 
 among books of this class.” — Notes 
 and Queries. 
 
 “A treasure to every reader who 
 may be fortunate enough to possess it. 
 Its perusal is like inhaling essences ; 
 we have the cream only of the great 
 authors quoted. Here all are seeds or 
 gems.” — English Journal of Education. 
 
 “Mr. Southgate’s reading will be 
 found to extend over nearly the whole 
 known field ©f literature, ancient and 
 modern.” — Gentleman's Magazine. 
 
 “Here is matter suited to all 
 tastes, and illustrative of all opinions — 
 morals, politics, philosophy, and solid 
 information. We have no hesitation 
 in pronouncing it one of the most 
 important books of the season. Credit 
 is due to the publishers for the 
 elegance with which the work is got 
 up, and for the extreme beauty 
 and correctness of the typography.” — 
 Morning Chronicle. 
 
 “Of the numerous volumes of the 
 kind, we do not remember having 
 met with one in which the selection 
 was more judicious, or the accumula- 
 tion of treasures so truly wonderful.” 
 — Morning Herald. 
 
 “Mr. Southgate appears to have 
 ransacked every nook and corner for 
 gems of thought.” — Allens Indian 
 Mail. 
 
 “The selection of the extracts has 
 been made with taste, judgment, and 
 official nicety.”— Morning Post. 
 
 “ This is a wondrous book, and con- 
 tains a great many gems of thought.” 
 — Daily News. 
 
 “As a work of reference, it will be 
 an acquisition to any man’s- library. ” 
 — Publishers' Circular. ' 
 
 “ This volume contains more gems 
 of thought, refined sentiments, noble 
 axioms, and extractable sentences, 
 than have ever before been brought 
 together in our language.” — The Field. 
 
 “ Will be found to be worth its 
 weight in gold by literary men.” — 
 The Builder. 
 
 “ All that the poet has described of 
 the beautiful in nature and art; all 
 the wit that has flashed from preg- 
 nant minds; all the axioms of ex- 
 perience, the collected wisdom of 
 philosopher and sage, are garnered 
 into one heap of useful and well-ar- 
 ranged instruction and amusement.” 
 —The Era. 
 
 “ The mind of almost all nations 
 and ages of the world is recorded 
 here.” — John Bull. 
 
 “This is not a law-book; but, de- 
 parting from our usual practice, wo 
 notice it because it is likely to be 
 very useful to lawyers.” — Law Times. 
 
 “ The collection will prove a mine, 
 rich and inexhaustible, to those in 
 search of a quotation.” — Art Journal. 
 
 “ There is not, as we have reason 
 to know, a single trashy sentence in 
 this volume. Open where we may, 
 every page is laden with the wealth 
 of profoundest thought, and all aglow 
 with the loftiest inspirations of genius. 
 To take this book into our hands is 
 like sitting down to a grand con- 
 versazione with the greatest thinkers 
 of all ages.”— Star. 
 
 “The work of Mr. Southgate far 
 outstrips all others of its kind. To 
 the clergyman, the author, the artist, 
 
 and the essayist, 1 Many Thoug 
 Many Minds’ cannot fail to n 
 almost incalculable service.”-j 
 burgh Mercury. 
 
 “We have no hesitation whl 
 in describing Mr. Southgate's i 
 very best book of the class. Tl 
 positively nothing of the kind I 
 language that will bear a moJ 
 comparison with it.” — ManA 
 Weekly Advertiser. 
 
 “There is no mood in whil 
 can take it up without deriving 
 it instruction, consolation, and a 
 ment. We heartily thank Mr. I 
 gate for a book which we shall rj 
 as one of our best friends and 
 panions.” — Cambridge Chronicle. 
 
 “ This work possesses the ms 
 being a magnificent gift-book, a! 
 priate to all times and seasons; — a 
 calculated to be of use to the sol 
 the divine, or the public mi. 
 Freemasons' Magazine. 
 
 “It is not so much a boolil 
 library of quotations.” — Patriot. I 
 
 “ The quotations abound in 
 thought which is the mainspril 
 mental exercise.” — Liverpool Co J 
 
 “For purposes of apposite c, 
 tion it cannot be surpassed .”— B 
 Times. 
 
 “It is impossible to pick i 
 single passage in the work 
 does not, upon the face of it, j 
 its selection by its intrinsic me: 
 Dorset Chronicle. 
 
 “We are not surprised that a S 
 Series of this work should have 
 called for. Mr. Southgate ha 
 catholic tastes desirable in a 
 editor. Preachers and public spe 
 will find that it has special us< 
 them.”— Edinburgh Dai y Review 
 
 “The Second Series fully sui 
 the deserved reputation of the F 
 — John Bull. 
 
 LONDON: CHARLES GRIFFIN & COMPANY'. 
 
 V