BRITISH MANUFACTURES. CHEMICAL. BY GEORGE DODD. LONDON: CHARLES KNIGHT AND CO., LUDG ATE STREET^ 1844. Loudon : Printed by William Clowes and Sons, Stamford Street. iii CONTENT S. PAJE INTRODUCTION 5 CHAPTER I. CHEMICAL MANUFACTURES IN GENERAL 19 CHATTER II. SULPHUR AND SALT, AS SOURCES WHENCE OTHER COMMODITIES ARE OBTAINED 26 CHAPTER III. SULPHURIC ACID; SODA; CARBONATE OF SODA ; MU- RIATIC ACID; CHLORINE; BLEACHING POWDER ; AND ALUM:— AS PRODUCED MAINLY BY THE AGENCY OF SULPHUR AND SALT 49 CHAPTER IV. SOAP, POTASH, AND CANDLE MANUFACTURES .... 91 CHAPTER V. COLOURS; OILS; TURPENTINE; RESINS; AND STARCH 1^7 CHAPTER VI. PORCELAIN AND POTTERY MANUFACTURES 167 CHAPTER VII. STREET-GAS MANUFACTURE 224 ( 5 ) BRITISH MANUFACTUllES. CHEMICAL. I^TEODLCTIOX. The words Chemist, Chemistry , Chemical, &c., ara associated with widely different meanings, in the minds of different persons. Some think that the only real cliemist is one who keeps a doctor's shop," wears a clean white apron, stands behind a nice mahogany coun- ter, and dispenses his i)ennyworths of salts, pills, and magnesia. Others, knowing or hearing that crucibles, retorts, alembics, and other working apparatus, are used by the practical chemist of present days, and were used by the alchemist of earlier times, and learning also that there are in chemical operations certain curious transformations of liquids into opaque or transparent solids, metals into vapour, &c., entertain an idea that there must be something mysterious about chemistry, and that a chemist must be a sort of Dr. Faustus, a cunning man" who sees farther than other people. A third class, better informed than the others, have an acquaint- ance, more or less general, with the great chemical li 6 INTRODUCTION. truths developed by such men as Priestley, Lavoisier, Black, Dalton, Davy, Gay-Lussac, and Faraday ; but, regarding chemistry in a purely scientific point of view, they are scarcely prepared to rank it as connected with one of our great branches of national manufacture. When the matter is viewed, however, a little steadily, and is stripped of certain parts which do not properly belong to it, we can form a tolerably exact notion of the proper acceptation of the terms employed, and how it arises that reputed magic, mystery, science, manufactur- ing art, and shopkeeping, become mixed up in such an incongruous manner. In the first place, it will be well to bear in mind that alchemy was the parent of modern chemistry, bearing some such relation to it as astrology bore to astronomy. The astrologer studied the movements of the planets and stars, under the idea that they had an influence over his destiny in this life, and that possibly he might obtain thereby a foreknowledge of what this destiny was to be : the search was a fruitless one, so far as regarded the immediate object in view ; but he did observe the move- ments of the planets and stars, and thus accumulated a knowledge of a large number of facts which have been valuable working tools to astronomers of later times. In like manner the alchemist, entertaining a crude notion that coarse cheap metals might be transmuted into gold, feet to w^ork to discover the agency vvhereby this might INTROBUCTiON. 7 be brought about ; fortunes were wasted, families ruined, and heads made crazy, without attaining the object in view ; but many curious facts were collected, in relation to the chemical action of different substances on each other, which have rendered great assistance to the more rational chemists of later ages. We thus get rid of the confusion arising from associat- ing chemistry with the dark and mystic proceedings of alchemy : we have only to consider that alchemy was an early and imperfect stage of chemistry ; the mutual action of various substances on each other being studied — not, as in modern chemistry, for a practical and attainable object, but for an object which is now known to have been unattainable. Next may be explained away the vagueness of asso- ciation between chemistry and the retailing of medicines. Before the Reformation, there were no recognised pro- fessors of the healing art in this country ; the monks and the alchemists being, in fact, almost the only doctors. The former laid claim to supernatural aid in the prepara- tion of medicines ; while the latter, not content with trying how to make gold, sought for an universal specific which should cure all ailments whatever. The grocers', or, as we should now call them, the chandlers' shops, were supplied with the few drugs then used as medicines, and the shopkeepers were w^ont themselves, occasionally, to act the part of doctors, and prescribe medicines for the B 2 8 I^^TRODUCTIOX, ailments of their neighbours ; while the barbers took to themselves the office of drawing teeth, letting blood, and performing the simpler kinds of surgical operations. But about three centuries ago the College of Physicians was established with a view of bringing the whole circle of medical operations under control ; the selling of drugs, too, was afterwards separated from the selling of groceries. The apothecaries^ to whom the drug department was intrusted, gradually assumed the privilege of attending patients, and also claimed the exclusive right to sell medicines ; but they could not retain both privileges, and hence arose another class still, the chemists and druggists. These latter, considered simply as shopkeepers, are not necessarily supposed to know what medicines are suited to certain diseases ; nor, on the other hand, are they simply retailers : as druggists, they sell in small quanti- ties what they purchase in larger bulk ; and as chemists or pharmaceutists, they study the means of preparing a mixed medicine from simpler chemical materials ; requir- ing a certain knowledge of chemistry to effect this, but leaving to the physician or the apothecary the decision of the fitness of the medicine for the disease which it is intended to cure. It will perhaps, therefore, clear up matters a little to say, that if the proprietor of one of these shops gives advice as to the treatment of any ailment, he does so as an ApotJiccary ; if he sells a medicine, such as rhubarb, or I^'TRODucTIO^^ 9 salts, in the same state as that in which he bought it, but in smaller quantity, he does so as a Druggist ; but if he prepares a pill, or mixture, or a compound medicine from different elements requiring different chemical modes of treatment, he does so as a Chemist^ or a Pharmaceutist , or (to use the more convenient French term) a Pharmacien. But the proper acceptation of the word chemist has yet to be considered. The pharmaceutist does not dis- cover the chemical properties of bodies ; he applies them, when discovered, to make numerous compounds. The real chemist, the man to whom the appellation in its highest sense is given, is he who discovers the great laws of chemical affinity, of definite proportions, of fusion, ebullition, vaporization, combustion, composition, decomposition, and all the many phenomena of a kindred nature. He does not, like the alchemist of old times, carry on his researches for a visionary and impracticable end ; nor, like the physician, docs he practically apply chemicals and drugs as healing remedies ; nor, like the pharmaceutist and druggist, does he make medicines according to prescribed rules, or sell them by retail ; but he seeks to establish those great truths with respect to the composition of bodies, which may be available . to every one ; and it is thus that men like Davy have at- tained the lofty position which their names occupy. One other aspect under which chemistry is talked of and studied is still to be noticed ; namely, its connexion 10 IIsTIlODUCTIOX. with manufactures. What is a manufacturing chemist ? What is the link which binds the science of chemistry with the industrial arts ? These points are not difficult to answer. Many of the more important chemical com- pounds are so largely used in the arts, that nothing less than large manufacturing arrangements would be ade- quate to their production. Take, as an example, sul- phuric acid (oil of vitriol) : the scientific chemist studies the nature and composition of this acid, discovers that it is formed of two simple elements, detects the exact proportion in which these two elements exist in it, tries experiments as to its action on water and on various other bodies, and groups together distinct statements as to all the results which he is able to obtain ; but he has not the facilities, nor is it a part of his object, to make this acid for sale. Again, the physician studies the effect of this acid, alone or in combination with other substances, on the human body ; and the pharmaceutist studies the mode of bringing it practically into combina- tion with other agents ; but neither the one nor the other attend to the making of the acid itself. The manufac- turing chemist takes this larger and more commercial tpart of the arrangement ; and he therefore holds a middle place : being indebted to the scientific chemist for the discovery of the elements and properties of the substance to be made ; and leaving to the physician, the pharma- ceutist, the dyer, the calico-printer, and others, the IIvTEODUCriON. 11 study of the best modes of applying the substance, when made, to any practical purpose. If these few explanations are borne in mind, they may perhaps help to remove some little ambiguity as to the meaning of words, by showing the different interpreta- tions put upon the word " Chemist," and their relative bearings one on another. This volume is intended to convey a general outline of the modes of manufacturing some of the chief chemical agents, as conducted in our own country in the present day. There are two reasons why the details will be limited to a few of the principal chemicals : 1st, because the space devoted to the subject is small ; and 2ndly, be- cause, on account of a general analogy observable in the manufacturing processes, one process becomes an index to many others. It will be useful, however, to preface the details by a notice of some of the chief chemical laws or-principles which govern the processes of manufacture. The most beautiful and valuable of these laws is per- haps that of (iffinity. By this is meant a tendency in two or more chemical bodies to unite and form one com- pound substance, the tendency being stronger in some instances than in others : what this affinity really is cannot be told ; we know nothing more about its intimate .nature than we do of gravitation : in both cases it is the 12 I^TRODUCTIOX. fffect wliich observers and experimenters regard, the agent itself being known only by the effects which it produces. If all bodies tended to unite with equal readi- ness, there would be no definitely compounded substance whatever, for every element would be strong enough to disturb every other, and all would be in confusion ; but there is a kind of elective or preferential afiinity, v/hich prompts two bodies to combine together rather than cither of them with a third, and this gives rise to some degree of stability in the compound substances with which we are familiar ; because two bodies, when com- pounded together by the affinity existing between them, cannot be decomposed except by some agent having a stronger affinity for one or other of them. Hence it is one of the important objects of a scientific chemist to discover the relative strength of this affinity among a great many substances. It has been found, for example, that sulphuric acid unites more powerfully with lime than with magnesia; still more so with soda, and most powerfully of all with potash. An immediate power of great value results from this elective affinity ; for a manulacturing chemist, observing- and acting upon these various degrees of strength, can produce one compound by decomposing another. A beautiful example of this will be explained in the body of the volume in reference to common salt : this consists of chlorine and sodium, but the two elements are not I^'TRODUCTIOX. 13 very strongly united, inasmuch as they can be sepa- rated by many different agents, and, by taking advantage of the different degrees of elective affinity, chloride of lime or * bleaching-powder,* muriatic acid, carbonate of soda, and many other valuable bodies, may be produced mainly by the agency of common salt. Another important principle is the difference of form which different bodies put on at the same temperature : some assume a hard earthy state, some a crystalline state, some a liquid, some a gaseous ; and this is often made a means of separating the elements of a compound body. Water, for example, boils and passes off in vapour at a temperature of 212°, while spirit boils at a much lower temperature ; and therefore by keeping a mixture of the two at a lower temperature than 212°, the spirit may be in part separated from the water : this is, indeed, the principle of distillation, however conducted. The crystalline arrangement, too, is a valuable one to the manufacturer. It often happens that when several •elements are compounded together in a liquid, one or two of them may be sepai^ated from the rest by allowing them to crystallize ; this may be eftected when one part of the compound has a tendency to crystallize sooner than the others. There is a very pretty exemplification of this in the making of alum, which we shall describe in a future page. This principle (the difference in the form of different B 3 14 I^vTHODUCTION. bodies at the same temperature) exhibits itself in so man}^ ways, that the chemical manufacturer avails himself of it in almost every step of his progress. Two vessels, for instance, may contain two liquids, each composed of two different elements, and both liquids may be clear and transparent; but in adding these two liquids together, three out of the four elem(»nts may combine and form a ternary or three-fold compound, leaving the fourth to fall to the bottom of the vessel in a fine earthy state, so as to be easily separable from the liquid. In such case the fourth, or isolated element, has a less intense affinity or attraction for each and all of the other three, than they have for each other, and is besides of such a nature as to present a fine earthy or sedimentaiy texture at that temperature. The relation which exists between heat and chemical elements is another great department of chemical science, which must be extensively known to the manufacturer before he can make his acids and alkalis, his salts and solutions. We are accustomed, in common life, to speak of all substances as being solid, liquid, and gaseous,^ach substance having some one of these forms definitely. So indeed they have, in reference to any one prescribed temperature: for instance, at a temperature of 130° tallow is a liquid, but wax is a solid ; at 450° tin is a liquid, lead is a solid. But in taking a comprehensive and general viev/ of the whole range of substances, there UsTROBUCTION. 15 is reason to believe that the great bulk of them are susceptible of all the- three forms, according to the heat which they contain. It is true that in some cases the attainable heat is never high enough, or the cold intense enough, to obtain these results ; but ice, water, and steam will indicate our meaning as to the broad facts. A manufacturing chemist has to make himself prac- tically acquainted with the fusing-point (which separates solid from liquid) and the boiling-point (separating liquid from vapour) of a large number of substances; since it often happens that his only means of manufac- turing one substance from another, consists in separating them at a particular fusing and boiling point. Some very important points arc involved in the group- ing of chemical compounds into acids, alkalis, oxides, salts, &c. ; forming, in fact, the very alphabet of many manufacturing processes. In the earlier times of che- mistry, acid was the name applied to anything which was sour to the taste ; but modern chemistry has greatly ex- tended the application. They are, as now enumerated, generally but not always sour, having generally a great affinity for water, redden most vegetable blue colours, and combine readily with most alkalis, earths, and oxides of metul ; some are solid, some liquid, and some gaseous ; and nearly all of them contain either oxygen or hydrogen as one of the ingredients, every acid being a compound. Alkalis are also compound bodies, having several valuable 16 INTRODUCTION. properties, among' which one is a strong tendency to combine with rx'ids.*^ Salts are the combinations of acids with earths, or alkalis, or metallic oxides, possessing* pro- perties often wholly different from those of the com- ponent ingredients ; thus, sulphuric acid, a burning and powerful liquid, when combined chemically with the mild and inodorous substance magnesia, constitutes the peculiar crystalline ^ Epsom salts,* a body essentially different in its properties from the substances of which it was made. All these are points with which a manufixcturing chemist must be well acquainted, since he has to avail himself of them in the process of manufacturing one sub- stance from another. The complexity in the relations existing between different substances is greater than can possibly be conceived by those who merely view matters in their e very-day phase ; and yet this complexity must be reduced to something like order and regularity before practical rules can be deduced and laid down. It is in- deed a startling fact, that all the objects which surround us on this earth ; all that is within and upon the earth ; the air which we breathe, and the birds which inhabit it ; the waters, the rock§ : the trees, plants, animals — all that can meet the eye and the ear on earth, whether living or lifeless, are made out of so few as fifty-four different substances ! Though there are millions of dis- tinct objects, yet (so far as the present state of science I^TKODucT^ox. 17 V has revealed) it does not appear that there are more than this number of different elemenf&ry substances from ^vhich they are formed ; most of the bodies with which we are cognizant being compounded of some two or more of these elements. To any one who has paid a little attention to chemis- try, these broad facts are well known ; but a little eluci- dation may be desirable for some readers. The greater part of these elements are metals ; but of those which are not metals, four of the most important are oxygen, hydrogen, nitrogen, and carbon. Now these four, in their simple and uncornpounded state, are very little known to us in every-day life ; but when combined two or more together, they form a surprising number of well- known substances. Of these a few may be here enu- merated : — Oxygen and hydrogen .... form .... Water. Oxygen and nitrogen ) various ( ^tmospheric air. < Laui^hin<^-(>;as. P™P°"'«»s|Aq«Sfortisr Oxygen and carbon Carbonic acid. „ „ i oth^-'i 1 Oxalic acid. " ' ( proportions j Hydrogen and nitrogen Ammonia. Hydrogen and carbon Street-gas. Nitrogen and carbon Cyanogen (a gas). Hydrogen, nitrogen, and carbon. . . .Prussic acid. r Sugar, starch, alcohol. Oxygen, hydrogen, and carbon C^^c- 1 acetic acid, and many cording to the proportions) 1 other vegetable pro- l ducts. Oxygen, hydrogen, nitrogen, and [Albumen, fibrin, gela- carbon (according to the propor-<[ tine, gluten, and many tions) [ other animal products. 18 INTRODUCTION^. The permutation of numbers, which form the arith- metical amusements of many a schoolboy, are not more surprising in their amount, while they are far less im- portant in practice, than those among the fifty-four ele- mentary substances ; and when it is considered that the skill of a chemist — whether of a theoretical chemist who studies the laws of his subject, or of a manufacturing chemist who avails himself of those laws in practice — depends mainly on the extent to which he is acquainted with these permutations, it will not appear surprising that chemistry is deemed a progressive science, always advancing beyond the point from whence we started, and yet always showing that there is an indefinitely ex- tended region yet to explore. ( 19 ) CHAPTER I. CHEMICAL MANUFACTURES IN GENERAL. Or the countless articles which every-day life presents to us, coming more or less under the general denomina- tion of chemical substances, some are prepared quite in a domestic way, with very few appliances of skill or im- plements ; some are brought to a saleable form by the shopkeepers who sell them ; some arc sold nearly in the state in which they are procured from mines or other natural sources ; while others require the aiTangemerits and extensive resources of large factories. There are some, too, such as soap, street- gas, porcelain, and baked earthen- ware, which, although not usually classed among chemical manufactures, yet involve so many of the peculiarities of chemical combinations as to be nearly allied to the others. For all these reasons a really strict selection of details for the present volume will be quite impracticable ; and we shall have accomplished the object intended if we succeed in giving a slight outline of some of the broader features of the subject. Generally speaking, the chemical works, strictly so called, are those in which the more important of the acids, alkalis, and salts are made ; such as sulphuric, nitric, and muriatic acids ; soda in various forms, chlorine, alum, metallic salts, &c. ; while other factories are desig- nated from the kind of substance made, such as white-lead 20 BRITISH MANUFACTURES. works, colour works, &c. But all of them are influenced both by political and by scientific events in a remarkable degree. That such establishments should be affected by the current of scientific discovery is what may reasonably be expected, since every advance in our knowledge of the constitution of bodies is likely to work changes in the modes of producing those substances. But in what way political matters are found to bear on the question may not be so obvious. A few considerations will, however, ^end to show the kind of connection between these appa- rently disconnected agencies. If a manufacturer prepares certain chemical substances (say) from sulphur ; and if political, or diplomatic, or fiscal disagreements should occur between England and the country whence this sulphur is produced, then the manufacturer might be constrained to procure his sulphur from some other source, perhaps by a complicated process on one of the English ores of sulphur. Again, suppose the English govern- ment removes the tax previously imposed at a heavy rate on some article of abundant supply, such as common salt, then the manufacturer may be induced to employ this material as a fund whence he may procure acids or alkalis previously procured from a more expensive source. Now these are not merely supposed cases ; they have actually occurred within the last few years, as we shall show farther on ; and they illustrate the kind of effect w hich legislative or political occurrences are calculated to produce on chemical manufactures. The imposition or the removal of an excise duty on a commodity of home production ; the imposition or the removal of a customs' duty on an imported foreign product ; the establish- CHEMICAL FACTORIES. 21 mcnt or the cessation of commercial intercourse ^vith a country richly provided with some commodity which we require in our manufactures; the concentration, in the hands of a few, of a commodity required by the many • the legislative enactments which occasionally give rise to a demand for a particular commodity at a particular time ; — all or any of these may work great changes in the arrangements of an establishment where chemical manu- factures are carried on, irrespective of the still greater changes which naturally result from scientific discoveries in chemistry. Chemical manufactures, like most others on a largo scale, are carried on chiefly in the midland and northern counties. In most instances the chemical works are situated somewhat beyond the precincts of a large manu- facturing town, since they require more space than can conveniently be procured within a town, and are liable to give off vapours and gaseous products, which are better at a distance than in close proximity to dwelling-houses. They are also generally situated near seaports, for con- venience of shipment. Glasgow, Newcastle-upon-Tyne, and Liverpool are perhaps the three principal centres for this class of manufactures. With respect to Glasgow, Dr. Thomson, at the meeting of the British Association in that city in 1840, gave some interesting details respect- ing the chemical manufactures of the district. He alluded especially to the vast works at St. RoUox, in the northern suburb of the city, where the furnaces and buildings extend over an area of ground unparalleled, we believe, by any similar works, and where a giant chimney rises to a height exceeding that of St. Paul's by a hundred feet. The factory was first established as sulphuric acid 22 BlilTlSH MANUFACTURES. works in the latter part of the last century ; they were at first small in size, and have risen to their present state by slow degrees. Besides this acid, bleaching-powder, or chloride of lime, is made at these works, a material of vast importance in reference to many branches of manu- facture. Soap and other articles are also made at St. Rollox. Dr. Thomson also alluded to the alum manu- facture, for which there are two establishments near Glasgow ; one of these we shall notice further on ; while at the other, besides alum, is made prussiate of potash and Prussian blue. In another chemical factory near Glasgow is made, among other things, bi-chlorate of potash, highly useful to calico-printers ; in another, acetic acid and pyroxalic spirit are distilled from wood ; in others iodine ; so that, taking the whole of these collec- tively, Glasgow may be deemed one of the chief centres of manufacturing chemistry. The neighbourhood of Newcabtle, too, is deserving of attention in this respect. The busy Tyne exhibits along both its banks, all the way from Newcastle to Shields (a distance of seven or eight miles), a continued succession of factories — here of glass, there of coarse pottery ; at other spots, of chemicals, of lead, iron-works, oil-mills, engine-factories, and others which tend to swell the im- portance of this bustling and thriving neighbourhood. Of these seats of manufacture, the chemical works are the most conspicuous, from the enormous height of their chimneys. No other factories or works have such lofty chimneys as chemical works, because no others give forth so many gaseous products likely to be of a deleterious character. In some of these instances (as we have jusfc intimated) the chimneys considerably exceed St. Paul's CilEMlCAL TACTORIES. 23 Cathedral in height. In past times many of the chemical works were regarded (and correctly so) as pests and plague-spots, bringing desolation on all the vegetable products near them ; blasting the trees, and stunting the growth of almost every kind of field and garden produce. Numerous were the disputes between the various parties on these points ; and an avowed good was, in this respect, always accompanied by an equally avowed evil. But modern research has wrought surprising changes in this respect. Every year adds something to the list of pro- cesses whereby a deleterious gas, previously sent forth into the atmosphere, becomes a source from which other and valuable products are derived ; and it is scarcely too much to expect that such improvements will gradually be made as to render the lofty chimneys less and less neces- sary — leaving them as memorials of a past and less skilful state of the manufacturing arts. The Tyne separates Newcastle from Gateshead, the latter being to the former what Southwark is to London ; and at a distance of a mile or two eastward from Gates- head is one such chemical work, which may be regarded as a type of the rest. The works occupy a position be- tween the South Shields Railway and the river ; and like most places in the neighbourhood, have abundant means of intercourse with the great central depot, Newcastle, by cheap railways and still cheaper steam-boats. The Londoners have their fourpenny steamers, but the good folks of Newcastle can have a nine miles' trip for three- pence ; and this facility, together with railways running along both banks of the Tyne, gives rise to an incessant and extensive intercourse. On approaching the works, it is soon evident that they •24 13RITiSH IMANUFACTURES. are of the class \vliere a large number of buildings are spread over a great area of ground, rather than exhibiting one huge building, such as is so often seen in the cotton districts. The buildings are of various sizes and shapes : some lofty, some shallow ; some long and broad, others nearly square ; some exhibiting within dry and dusty pro- cesses, others heat and vapour, others vessels and liquids ; one with a lofty and well-proportioned chimney, others with chimneys of more humble dimensions. Narrow passages and square courts separate these buildings one from another ; and while passing through these passages, and the buildings adjacent to them, every one must be- come sensibly alive to the odour of the acids and other chemicals under process of manufacture. Common sulphur and common salt are now the two great agents in the production of the chemicals in most familiar use. Sulphuric acid, or ' oil of vitriol,' chloride of lime, or * bleaching-powder,' muriatic acid, or ' spirit of salt/ the soda-ash employed by glass-makers and soap-makers, the common soda employed in washing — all result from certain modes of applying one or other of these cheap and abundant substances ; and these are precisely the commodities most generally made at chemical works. Nothing can more beautifully illustrate the general character of chemical composition and decomposition than the steps by which one substance becomes transformed into another, as developed at a chemical work : the pro- duction of an acrid and poisonous body from harmless ingredients ; the production of a liquid from two gases, or of a gas from two liquids ; the generation of colour from the mixture of two colourless bodies ; the transformation of an opaque earth into a colourless crystal ; — these and CHEMICAL rACTORIES. 25 analogous phenomena are constantly presented during- the progress of chemical manufactui'es. Sulphur and salt being thus two of the most valuable sources of chemical commodities, it may be well to de- vote a chapter to them in their individual Ibrm, before tracing their subsequent transformations. 26 BRITISH MANUrACTUBES. CHAPTER II. ON SULPHUR AND SALT, AS SOURCES WHENCE OTHER COMMODITIES ARE OBTAINED. There is nothing so very especial in the nature of these two chemical substances as to lead to their being grouped together, and being placed distinct from others, were it not that they are so singularly valuable as sources whence other commodities may be obtained. As, however, there are some interesting chemical details connected with the original production and extraction of these valuable arti- cles, we will collect from different sources a few facts on the matter, commencing with Sulphur There may perchance be those who would ask — Of what use can sulphur be, except to make matches ? " That it has numerous other uses, however, will be readily conceded when we state, that although an enormous quan- tity of the article is produced in our mining districts for home consumption, yet so great is the demand for it, that forty or fifty thousand tons are annually imported from Sicily ! Sulphur is an abundant article in the neighbourhood of volcanoes. It is widely diffused throughout the mineral kingdom, but is more abundant in some places than in others. In Iceland it is found in combination with gyp- sum ; at Conil, near Cape Trafalgar, it occurs in a crys- SIJXPHUR A^D SALT. 27 talline form ; at Urbino in Italv, at Aragon in Spain, and at Lauenstein in Hanover, large quantities are found. Beds of sulphur are very numerous in the tertiary blue clay of Sicily, a country which has supplied the greater part of Europe with sulphur for centuries, without any sensible diminution of its own stock. The principal scene of the mining operations in Sicily is near Catolica. The sulphur appears in veins of vari- ous colours, mixed with clay and gypsum. The general appearance is that of a shining grey colour, but large pieces are found which are red and transparent, and are called by the workmen virgin sulphur. Large black patches also appear, consisting of a chemical combination of clay and sulphur : these patches contain beautiful crys- tals of sulphate of lime of various colours — yellow, violet, grey, and black. The preparation of sulphur in Sicily, for exportation, is a very simple affair. Large cauldrons are formed in an elevated mound of earth, each cauldron being about seven feet in diameter and five feet deep. Large masses of the sulphur-stone are piled up round the edge of each cauldron, and gradually inclined so as to meet in a point at the centre ; thus forming a sort of conical mound or cover over each cauldron. The spaces between the large masses are filled up with smaller lumps, and these again with dust of the same material. A quantity of straw is then spread over the mound and ignited ; the straw burns, and the fire soon extends to the interior ; so that the sul- phur, as it melts, flows down into the cauldron. After this process has continued for about eight hours, the melted sulphur is drawn out at an aperture in the lower ])art of the cauldron, and received into wooden moulds 28 BRITISH MANUFACTURES. ^vhich have been previously wetted to prevent the sulphur from adhering to them. In about a quarter of an hour the sulphur becomes solid, and is then fit for exportation. In this state it is called block sulphur^ and sometimes massive or native sulpJmr, Vast quantities of sulphur are procured in our copper- smelting districts, under the name of roll sulphur, from the cylindrical shape in which it is cast. Most metallic ores, in the state in which they are dug from the earth, contain sulphur. The iron and copper pyrites, which so greatly enrich England, are compounds of those metals and sul- phur. In the smelting of copper-ore, the sulphur is sepa- rated from the metal, melted in earthen pots, and cast into wooden cylindrical moulds which give it the form of rolls. Another form in which sulphur is obtained is that of a powder, called flowers of sulphur. The sulphur is melted in a vessel called an alembic. At a temperature of about 600^ the sulphur rises in the form of vapour, which being collected in the upper part of the alembic, cools down into the form of flowers of sulphur. This process is called sublimation. Products obtained in this way were supposed by the alchemists to resemble the flowers of plants ; hence the name : but the peculiar resemblance which they saw, or fancied they saw, is not very clear. Sulphur is an elementary body ; that is, the chemist has never been able to resolve it into simpler parts. We need scarcely refer to its pale yellow colour, as it is so well known. Its weight is about twice that of an equal bulk of water. When rubbed with a piece of warm flannel, it becomes negatively electrified. One curious consequence of this property is frequently noticed by the druggist : in grinding a piece of roll sulphur in a dry SULPHUR AND SALT. 29 Wedgwood mortar, the resulting powder adheres with considerable force to the mortar, and will not fall out when the mortar is inverted : the reason is, the sulphur becomes negatively electrified by friction, and the mortar positively electrified ; and according to a well-known law of electricity, two bodies in opposite electrical states at- tract each other. Hence the adhesion of the sulphur to the mortar. Sulphur is insoluble in water and in alcohol ; but hot oil and some of the alkalis will effect its solution. It is very brittle. If a roll of sulphur be grasped by a warm hand, it will often break to pieces in consequence of its unequal expansion by heat. When exposed to heat a little above that of boiling water, it melts ; at 230° it is almost as liquid as water ; by raising the temperature to 600", its colour changes from a liglit to a deep yellow, then to orange yellow, then a shade of red comes over it, then brown, and at its boiling-point its colour is brov^'nish red; but the most remarkable circumstance is, that in- crease of temperature, so far from rendering sulphur more tiuid, as is the case with most other bodies, actually thickens it, and produces a thick viscid mass : thus at 230° sulphur is quite liquid, and can be poured out of the vessel containing it; at 338° it begins to be viscid ; at 428° it becomes quite thick ; and from 464° to SOO"* the vessel containing it may be turned upside down, and the sulphur will not flow out ; as it approaches the boiling- point, it becomes less viscid. These remarkable facts have not been explained. When sulphur is pure, it boils away at about 600°, and leaves no residue. If a quantity of sulphur be melted in a pipkin, and then set aside to cool, the surface will soon become solid. c so BRITISH ^.IA^•u^ACTl]RI:s, It we make two holes in the crust, near the edge, but opposite to each other, and incline the vessel, the melted sulphur will flow out into any other vessel placed to receive it, and air will enter at the other hole. On allow- ing the pipkin to cool gradually for a few hours, we shall And, on breaking open the mass, that the interior crust is composed of an immense series of small and beautiful crystals. The above are a few points relative to sulphur and its properties generally ; but we will abstract from the * Journal of the Statistical Society ' a somewhat fuller notice of the mode of procuring it in Sicily : — The Sicilian sulphur is found within the limits of a geographical line which commences at the river Macca- soli in the valley of Girgenti, runs northward as far as Lercara in the valley of Palermo, tends eastward to Cen- torbi in the valley of Catania, and thence runs south- westerly to Terranova in the valley of Caltanizetta, where it terminates. The area of the sulphur district is about 2600 English square miles. Destitute of timber, and diversified only by fruit-trees scattered around the vil- lages, it has few charms for the passing stranger beyond the fantastic shape of its cliffs and mountains. The man of science, however, who examines its soil, will find it replete throughout with objects of interest. The sulphur territory, the formation of which is tertiary, presents suc- cessive strata of shell, limestone, white and blue marl, intermixed with banks or beds of gypsum, and occasional patches of cretaceous matter. The sulphur is found im- bedded in the lowest stratum of blue marl, which is dis- tinguished from the upper one by the entire absence of shells. The district contains about 1 50 distinct mines, SULPHUR AXD SALT. 31 Y/hicli arc capable of yielding from 750,000 to 800,000 caiitars (about 50,000 to 80,000 tons) annually. Of the richest mines, those of Gallizzi, Sommatino, and Favara, the yearly production has been 100,000, 80,000, and 60,000 cantars respectively. ^' The visitor to a sulphur-mine usually descends by a plane or staircase of high inclination to the first level, where he finds the half-naked miner picking sulphur from the rock with a huge and heavy tool ; boys gathering the lumps together, and carrying them up to the surface ; and, if water be there, the pumpmen hard at work draining the mine. A similar scene meets his eye in the lower or second level. Above-ground the sulphur is heaped up in piles or fusing in kilns. Every stranger must be forcibly struck with the hardy and healthy look of the miners and burners, to which the lean and sickly aspect of the southern population forms a thorough contrast. The life of a pickman, which is some- times said to be hard and wearisome compared with that of the peasant, is in reality easy, and suitable to Sicilian taste. His working days do not exceed 250 in the year, and his hours of labour are only six in the day. Left, therefore, with eighteen hours a day to himself, he passes ihree-fourths of his time in eating, drinking, sleeping, and lounging about his village. Satisfied with animal exist- ence, the pickman seeks not intellectual pleasures at the cost of increased exertion. His wages rise and fall with the price of the mineral ; from I6d. to 20d. a day for himself, and about half as much for each of his boys, are reckoned good earnings. The pumpmen are ill-paid labourers compared with the pickmen. Their daily toil, if lighter, is longer and less intermitted ; and their occu- c 2 32 BRITISH MANUFACTURES. pation is productive of sickness rather than conducive to health. Constantly drawing in sulphuretted hydrogen gaSj which escapes from the agitated water, they suffer so severely in their eyes as often to become blind for twenty-four hours. They work for eight hours a day, and earn from Is. to Is, 4d, each. The burners, who extract the sulphur, by fusing the ore in kilns made of gypsum and stone, or sometimes in close vessels or fm^- naces, usually earn about I5. a day. ^'The sulphur thus obtained by liquation, when har- dened into cakes, is taken down to the coast by carriers and muleteers. These are mostly small farmers, who are paid by the load, according to the time of the year and the demand for their services. Being seldom trustworthy people, these carriers are engaged by a warranter, who, for less than Id. a can tar, becomes answerable for the safe delivery of the sulphur at the shipping-place. To Palermo and Catania the sulphur is conveyed in carts ; to the southern ports it is carried down on mules and asses. Such is the working part of a mining establishment. The overlookers are mining-captains, clerks, and a ma- nager. The mining-captain, chosen from among the pickmen for his knowledge of the mine, examines the veins and directs the operation. As the right-hand man of the manager, he is looked upon by the pickmen and others as a person whose good opinion it is worth while to cultivate. Living in a substantial and commodious house, and dressing in a neat and becoming manner on Sundays and holidays, he holds a respectable place in village society. He usually resides a few miles from the works ; but in some cases he dwells at the mine, where he is required to be in constant attendance from morning SULPHUR AND SALT. 33 till night. His wages are from 2s. to 45. a-day ; but many unlawful perquisites raise his earnings to a higher amount. After a few years' constant employment in a rich and extensive mine, he is usually able to retire with a competence sufficient for his limited wants. The clerks and watchmen, who keep account of piece-work and labourers* time, who receive the fused sulphur and weigh it out to the carriers, and who reside at the mine to take care of the works, usually earn from Is. Sd. to 2s. Sd, a-day. The manager or head-agent acts as treasurer and trustee for the owners or lessees of the mine. Aided by the mining-captain and the clerks, he engages and pays the workmen, and keeps the general accounts. His salary is from 4^. to 6s. Sd. a-day. His gains are perhaps double this amount ; so that he often makes his fortune in the course of a few years. The number of persons regularly employed in the sulphur-mines has been estimated at 4400, viz. : — 1300 pickmen, 2600 boys, 300 burners, and 200 clerks and others ; to which if 3600 persons occasionally employed, viz., 2600 carriers, and 1000 wharfingers, be added, the total amount will be 8000 persons more or less engaged in the extraction of ore and the exportation of sulphur. A small portion of the sulphur carried down to Girgenti serves for the use of a royal refinery, whence it is ex- ported to France and Austria in powder and in rolls. Previous to the sulphur contract the chief part was sent in cakes to England, France, Holland, Russia, and the United States, in the proportion of three-sixths to Eng- land, two- sixths to France, and the rest toother countries. In the Sicilian market sulphur is divided into first, second, and third qualities of Licata (each of which is 34 BRITISH MA^'U^ACTURES. subdivided into best, good, and current), and into first and second quality of Girgenti, with the like subdivisions. The first and second qualities of Girgenti correspond with the second and third of Licata/' Salt. We now transfer our attention from sulphur to salt, and show the general nature of its origin by describing salt-work operations in two or three different countries. Three French gentlemen many years ago published a description of the Salzburg Salt-Mines ; and, as this is deemed to be very correct, we will here transcribe it : — The salt-mines are at a little distance from the small town of Hallein, and at the foot of the Durenberg mountain. We seated ourselves in sledges, and were conveyed to the opening which leads into the interior of the mine. Before descending into the mine we equipped ourselves in the costume of the miners, which consisted of flannel waistcoat and trowsers, and a large white cape for the shoulders. These preparations are rendered necessary by the extreme humidity of the mine, which would effectually have destroyed the common articles of clothing. We were also supplied with strong shoes, a leathern apron, and a hood. We then seated ourselves on a sort of wooden horse called a ' wurst,' which moved on four small wheels. Three of the miners attached the traces of this machine around their waists, and dragged us slowly through a long gallery, on each side of which was an aqueduct constructed of wood. One of these con- veyed a supply of fresh water into the mine, and the other carried it off when it had become sufficiently im- pregnated with salt. In a quarter of an hour we reached SULPHUR AND SALT. 3$ the first shaft. It is not dug in a perpendicular direc- tion, but inclines at an angle of about 45°. It was along one of these that we were to descend to a depth of about eighty yards. The descent is effected in the following manner: — Two round and smooth beams are placed side by side on the lower part of the shaft, about a foot asunder. They somewhat resemble the machine used by brewers for lowering beer into cellars. They are fixed, and extend from the entrance to the bottom of the shaft. Upon these beams the person descending seats himself, placing his legs over each side, and thus slides to the bottom. A great rope is stretched on the right, about the height of the arm, in order to enable those who are descending to regulate the rapidity of their descent. One of the miners preceded each of us in the descent. My attend- ant placed himself between my legs, at the same time * cautioning me neither to move my arms nor feet. The men then asked us if we were alarmed ? to which, of course, we courageously replied in the negative. Then^ abandoning ourselves to the impulse of our own weight, and each of us holding in one hand a burning torch, we glided forward so rapidly, that we were at the bottom of the ^ rolle,' or beam, in half a minute. We then proceeded along another gallery, similar to the one at the entrance of the mine ; and descended still deeper into the mountain by two other roUes, on which, profiting by my previous experience, I kept my seat without assistance. This mode of descending was both easy and pleasant, and I even regretted that the fourth rolle was the last. The mountain within whose bosom we now were, is composed of a sort of rock-salt, which is in a constant 36 BRiTISII MANUrACTURES. course of growth or formation. The first excavations appear to have been made at a period so remote, that tradition has not even preserved -any records of the date at which the working of it was first commenced. These excavations consist of chambers six or eight feet square, into which water is conveyed by means of the aqueducts before-mentioned. The water enlarges these chambers by dissolving gradually the walls and roof. They are generally about six feet in height, and are filled as nearly as possible with water. If the chamber w^ere half filled with water, the sides only would be submitted to the process of solution, but, by being very nearly filled, the water attracts the saline matter contained in the roof, and the operation is carried on in the most rapid, and at the same time effective, manner. The miners term the roof of the chambers the ' ciel.' " The rock-salt is of different colours, but blue, grey, and yellow are the most common. Frequently it is friable, and sometimes slaty, and peels off in transparent cakes — resembling the tracery work produced on a win- dow by frost. There are often found, in a chamber of 613 yards in circumference, seven or eight masses of slaty rock three or four feet in diameter, v/hich do not contain any salt whatever. Of course these masses resist the direct action of water, but, as all the parts round them containing salt are gradually dissolved, they are in the end detached from the roof and deposited on the floor. We saw several of these in one of the cham- bers we examined. The water had been drained out of this chamber three weeks before, and it was illuminated with about fifty candles. One of these masses, like a shapeless column, reached from the floor to the ceiling ; SUJLrHUR AND SALT. 37 some, on being detached, had left cavities two or three feet deep, and several were still suspended. The miners pass carelessly under them. But that which caused me most alarm was to find myself under a ceiling 584 yards in circumference, on which the weight of the superin- cumbent mountain rested, and which was not even sup- ported by the vaulted form which nature usually gives to the roofs of subterranean caverns. It was perfectly flat, and was only sustained by the adhesive forces which existed between all the various parts of this immense apartment. The firmness thus occasioned is so great, that only one instance has occurred during several cen- turies of a ceiling having given way. There are thirty-six chambers excavated in the mountain. They are partly shaped by the action of the v> ater, and their dimensions are irregular, according as the mass composing the roof or walls is more or less charged with salt. Many chambers are excavated one over the other, thus forming different stories, the mass which separates one chamber from another serving the same purpose as boards and lath and plaster in houses, though of course much thicker. The miners informed us, while we were examining one chamber, that above us was a chamber at that time filled with water. It may appear singular that a large body of water thus situated should not find its way into the apartment beneath, but we found the ceiling scarcely humid. The reason of this is, that before the water is introduced, the floor is covered with clay, which is beaten down so as to render the surface impervious to the water. A kind of blue clay is used for this purpose, which is worked up into a proper consistence with wooden mallets ; and when it c 3 38 BRITISH MA^'UFACTURJ:S. no longer contains any rough particles it is spread over the floor. If it should leak, a little saw-dust is thrown into the water, and by this means the position of the outlet is ascertained, which is first of all enlarged, and then securely plugged with the clay cement. If the water escapes by one of the galleries, the gallery is abandoned to a certam distance, and endeavours are made with the cement to repress the passage of the water as much as possible. If this fails, however, it becomes necessary to open another gallery, and this is the most difficult task which the miners are called upon to perform. In executing this work they are obliged to divest themselves of every article of dress ; as, without this precaution, their clothing would absorb a strong saline composition, which would render it hard and brittle, and cause it to tear the skin. J could not think without compassion of these unfortunate men being thus employed for nine hours a-day for so small a recompense as twelve kreutzers {4d. or 4^