a j\ 
 
 ■531 
 
 THE CHEMISTRY 
 
 OF 
 
 COOKING AND CLEANING 
 
 RICHARDS and ELLIOTT 
 
Class 
 
 QLlAl 
 
 Book tRs J 
 
THE CHEMISTRY OF 
 COOKING AND CLEANING 
 
 A MANUAL FOR HOUSEKEEPERS 
 
 ELLEN H. RICHARDS 
 S. MARIA ELLIOTT 
 
 THIRD EDITION 
 REVISED AND ENLARGED 
 
 WHITCOMB AND BARROWS 
 BOSTON 1907 
 
HILARY of CONGRESS 
 Two Copies Received 
 
 SEP 30 190f 
 
 Copyrifht Entiy 
 
 COPY B 
 
 'No. 
 
 A 
 
 First Edition 
 
 Copyright, 1881 
 
 By Estes & Lauriat 
 
 Second Edition 
 
 Copyright, 1897 
 
 By Home Science Publishing Co. 
 
 Third Edition 
 Copyright, 1907 
 By Ellen H. Richards 
 
 Alfred Mudge & Son, Inc., Printers, 
 Boston, Mass., U. S. A. 
 
PREFACE. 
 
 IN this age of applied science, every opportunity 
 of benefiting the household should be seized 
 upon. 
 
 The family is the heart of the country's life, and 
 every philanthropist or social scientist must begin 
 at that point. Whatever, then, will enlighten the 
 mind, and lighten the burden of care, of every 
 housekeeper will be a boon. 
 
 At the present time, when the electric light and 
 the gas stove are familiar topics, there is, after all, 
 no branch of science which might be of more 
 benefit to the community, if it were properly un- 
 derstood, than Chemistry — the Chemistry of Com- 
 mon Life. 
 
 There is a space yet unoccupied for an elemen- 
 tary work which shall give to non-scientific read- 
 ers some practical information as to the chemical 
 composition of articles of daily use, and as to their 
 action in the various operations in which they are 
 employed. 
 
 The public are the more ready for the applica- 
 tion of this knowledge since Chemistry is taught 
 in nearly all High Schools, and most persons have 
 a dim idea of what some part of it means. To 
 gather up these indistinct notions into a definite 
 and practical form is the aim of this little book. 
 
iv PREFACE. 
 
 There is, lingering in the air, a great awe of 
 chemistry and chemical terms, an inheritance 
 from the age of alchemy. Every chemist can re- 
 call instances by the score in which manufacturers 
 have asked for recipes for making some substitute 
 for a well-known article, and have expected the 
 most absurd results to follow the simple mixing 
 of two substances. Chemicals are supposed by 
 the multitude to be all-powerful, and great ad- 
 vantage is taken of this credulity by unscrupulous 
 manufacturers. 
 
 The number of patent compounds thrown upon 
 the market under fanciful and taking names is a 
 witness to the apathy of housekeepers. It is time 
 that they should bestir themselves for their own 
 protection. A little knowledge of the right kind 
 cannot hurt them, and it will surely bring a large 
 return in comfort and economy. 
 
 These mysterious chemicals are not so many 
 or so complicated in structure but that a little 
 patient study will enable any one to understand 
 the laws of their action, so far as they apply to the 
 common operations of the household. 
 
 No attempt is here made to cover the whole 
 ground of chemical science, but only to explain 
 such of its principles as are involved in the raising 
 of bread, and in a few other common processes. 
 
PREFACE 
 
 To the Second Edition. 
 
 THE science of chemistry has made rapid 
 strides in the past fifteen years. Biological 
 science has sprung from infancy to sturdy man- 
 hood during the same time, and a knowledge of 
 both with their relations to each other is necessary 
 to the right understanding of the manifold opera- 
 tions of life. All the sciences and all the arts are 
 taxed by thej intelligent home-maker for the 
 proper foundation and continuance of the complex 
 life of the home. 
 
 The establishment of more homes and their 
 right conduct when established, which results in 
 the better utilization of time, money and strength, 
 means the perpetuity, prosperity and power of the 
 nation. 
 
 Without trespassing upon the domain of house- 
 hold bacteriology, a knowledge of the chemistry 
 of cooking and cleaning must include some dis- 
 cussion of the sources of dirt, its composition and 
 its dangers, and the discussion of methods for its 
 removal, which shall at the same time be speedy, 
 safe and effectual. 
 
vi PREFACE. 
 
 Experience teaches that in domestic work there 
 is no best rule of universal application. Circum- 
 stances vary so widely that principles, alone, can 
 be laid down. Each case requires a large propor- 
 tion of judgment — a compound of more complex 
 composition than any chemical substance ever 
 dealt with. 
 
 If any housekeeper finds a method better for 
 her purpose than the one specified here, let her 
 keep to its use and tell it to others. This work 
 will have accomplished its purpose if it interests 
 those who understand already the principles of 
 cooking and cleaning; gives a few answers to 
 those who continually ask "Why?" and "How?" 
 and stimulates to study and thought the many 
 who have long labored with willing hearts but 
 with untrained minds and hands. 
 
 Boston, 1897. 
 
CONTENTS. 
 
 PAGE 
 
 Preface to First Edition iii 
 
 Preface to Second Edition v 
 
 PART I. 
 
 Introduction I 
 
 I. Matter and Its Composition ... 5 
 
 II. Elementary Chemistry 12 
 
 III. Starches, Sugars, Fats, Their Preparation 
 
 as Food . .24 
 
 IV. Nitrogenous Constituents .... 47 
 
 V. Flavors and Condiments. Diet ... 56 
 
 • 
 PART II. 
 
 I. Dust . 71 
 
 II. Dust Mixtures (Grease and Dust) . . 87 
 
 III. Stains, Spots, Tarnish 100 
 
 IV. Laundry 118 
 
 V. Chemicals, and Their Use in the House- 
 
 hold 145 
 
 VI. Antiseptics, Disinfectants, Insecticidfs . 165 
 
 Books of Reference 181 
 
 Index . . . 183 
 
INTRODUCTION 
 
 To the Revised Edition of 1907. 
 
 IN the thirty years since this little book was 
 written, the interpretation of many scientific 
 facts has been changed as more facts have been 
 discovered, and also, in many cases, the method 
 of expressing the well-established facts has been 
 changed to agree with newer theories. 
 
 Although at first sight this seems discourag- 
 ing, it should not prevent an attempt to under- 
 stand some of the fundamental laws upon which 
 every-day life and health depend. The author 
 has already learned three different systems of 
 expressing the same facts in chemistry and 
 expects to learn yet another. 
 
 In making this revision a medium course has 
 been chosen. It is not prepared for the scien- 
 tific man, but its mission is now, as it has been 
 heretofore, to the average intelligent housewife. 
 She needs to see that there are reasons for things 
 in order to lift the monotonous operations of the 
 kitchen in particular, and the household in gen- 
 
2 THE CHEMISTRY OF 
 
 eral, from distasteful drudgery to a plane of 
 intelligent direction of scientific processes, the 
 results of which may be more or less controlled. 
 
 It is this sense of control, of power to pro- 
 duce desired results, which gives an interest to 
 daily duties. Since the good health and earning 
 capacity of the family depend upon the house- 
 mother's knowledge of the laws which govern 
 the daily making and baking and cleaning, surely 
 it will be worth her while to try to absorb the 
 spirit of modern scientific research, to observe 
 what goes on in her pots and pans, to watch 
 her oven, and especially to scrutinize her dish 
 washing. 
 
 Knowledge of foods and of chemical proc- 
 esses is increasing so rapidly that what is written 
 is out of date before the ink is dry, but a little 
 more or less exact information is not so im- 
 portant as that the spirit of inquiry, of open- 
 mindedness, shall pervade all departments of 
 household activity. 
 
 Thirty years ago very few grown women had 
 received any training in chemistry. Chemical 
 nomenclature was worse than Greek to them. 
 Today the majority of young housewives have a 
 small remnant of school chemistry among their 
 store of miscellaneous knowledge. It is to be 
 feared that it is rather vague, but chemistry is 
 
COOKING AND CLEANING. 3 
 
 not the bugbear it once was. The present day 
 housewife is not afraid of chemical substances. 
 
 The great difficulty in explaining chemical 
 results has been in showing the law of definite 
 proportions, that fundamental law, discovered 
 by Dalton, in and upon which the whole theory 
 has been built. 
 
 The law of exchange of different quantities 
 having different values not according to quan- 
 tity, but according to value, has always been 
 difficult to express. 
 
 One reason for dwelling upon the law of defi- 
 nite proportions is because the idea is so preva- 
 lent that if the effect of a teaspoonful is good, 
 that of a teaspoonful and a half is better, whereas 
 the extra half may be the cause of failure. The 
 long experience of a grocery clerk gives his hand 
 nerves such a response to weight that he may 
 dispense with scales in putting up a pound of 
 sugar. In this way the skilled cook tells the 
 proportions with the exactness of the balance, 
 but woe betide the unskilled housewife who 
 attempts the same trick. 
 
 One other fact in relation to science, and chem- 
 ical science in particular, must be borne in mind. 
 While much is known, there remains much more 
 still hidden. It is practical wisdom to use all 
 that is known and to accept results as far as they 
 
4 THE CHEMISTRY OF 
 
 prove beneficial, without waiting to learn all the 
 reasons why. Not that the search for reasons 
 should be abandoned, but that each bit of knowl- 
 edge should be applied as fast as gained. 
 
THE CHEMISTRY OF COOKING 
 AND CLEANING. 
 
 CHAPTER I. 
 Matter and Its Composition. 
 
 WE give the name matter to the objects Matter 
 which can be recognized by any one of 
 our senses. There are many kinds of matter and 
 many forms of one kind. Ice melts into water, 
 water changes into steam. In our stoves, the 
 hard, black coal disappears, leaving a soft, gray 
 ash, that weighs much less than the original coal. 
 Something has been taken away. 
 
 The leaf is covered by wind-blown soil and Chang 
 soon no leaf is there ; but the matter of which it 
 was composed is still somewhere, for that is 
 never lost. Living matter is in constant change 
 from one form to another. Our bodies are com- 
 posed of matter, and to their continued existence, 
 as well as to their growth, material substances 
 are necessary. Some changes come quickly, some 
 slowly. Years, ages even, are sometimes neces- 
 sary to bring about a result that is visible to us. 
 
 es in 
 Matter. 
 
6 THE CHEMISTRY OF 
 
 A familiar substance, sugar, for example, may 
 be subjected to different changes. Put two table- 
 spoonfuls of white sugar into a scant half cup of 
 water. The sugar disappears. The clear water 
 changes to a syrupy liquid. If the water is 
 allowed to evaporate slowly, the sugar is found 
 to remain. 
 
 A teaspoonful of sugar dropped upon the 
 warm stove changes in character. There ap- 
 pears a black mass, which is readily recognized 
 as charcoal. 
 
 Add a solution of an acid to a solution of an 
 alkali, and observe that the acid substance and 
 the alkaline substance are no longer in existence 
 as such. There is, instead, a neutral saline sub- 
 stance dissolved in water. The new substance 
 has the properties of neither of the others. The 
 acid and the alkali have lost their identity. 
 
 Dissolve a teaspoonful of sugar in a cupful of 
 water. Add a very little yeast and put the cup 
 in a warm place. Soon bubbles of gas rise and 
 break on the surface; while, on distilling the 
 liquid, a new acquaintance presents itself in the 
 form of alcohol. The first-mentioned change in 
 the sugar — the solution of it in water — is a 
 physical change; for the character of the sub- 
 stance is not permanently altered. The second 
 change — the charring — is a chemical change — 
 
COOKING AND CLEANING. 7 
 
 the substance loses its individual character. The 
 third change in the sugar — its fermentation — 
 which is most important for our present purpose, 
 is also a chemical change but one caused by the 
 action of life. When the syrup ferments, we 
 know that living organisms are at work in the 
 solution, changing the substance by their own 
 processes of growth. To this class, then, we may 
 apply the name biological change. Here belong 
 the changes in our own bodies which enable them 
 to live and grow. Death comes when these 
 " vital" changes can no longer proceed in a 
 normal, healthy manner. 
 
 Changes in matter, then, are of two kinds. 
 
 I. Physical. Change of form, without per- 
 manent loss of identity. This is brought about 
 by outside forces : heat, blows, etc. 
 
 II. Chemical. Complete change of character, 
 with or without change of form. This is brought 
 about by chemical agencies, by fire and electric- 
 ity — also forces from without. 
 
 Physical and chemical forces, working to- 
 gether, allow biological results, caused by living 
 cells producing energy by means of their life 
 processes. 
 
 Under these heads come the numerous changes 
 which every housewife observes and which all 
 should understand, so far as such understanding 
 is necessary for the true economy of the house. 
 
THE CHEMISTRY OF 
 
 Forms of 
 Matter. 
 
 We have seen that matter is subject to two 
 kinds of change. Experience teaches that matter 
 exists in three different forms — solids, liquids 
 and gases. It teaches, also, that by the action of 
 outside forces some solids become liquids and 
 some liquids become gases. The reverse proc- 
 ess, also, is known — gases change into liquids 
 and liquids into solids. The chemist or physicist 
 is able to change matter from one form into 
 another in many more- instances than are ob- 
 served in ordinary experience. 
 
 What causes can be made to bring about these 
 changes ? Before an iron kettle or stove can be 
 made, the metal from which it is formed must 
 be subjected to intense heat, when it will become 
 a liquid and can be poured into molds of any 
 desired shape. Solid ice melts or becomes water 
 at a low temperature; but at a higher degree of 
 temperature, the water becomes steam or gas. 
 Some solids, as camphor and iodine, sublime, that 
 is, pass directly into the gaseous form. 
 
 Heat, then, is one influence which brings about 
 a change of state in material substances. If heat 
 be abstracted from a liquid, the latter may be- 
 come a solid, as when water becomes ice. Like 
 changes are less readily brought about by pres- 
 sure, gases becoming liquids ; liquids becoming 
 solids. Cold and pressure, acting together, are 
 
COOKING AND CLEANING. 9 
 
 able to liquefy the air, and other gases once 
 called permanent. 
 
 Different degrees of heat produce varying Expansion, 
 degrees of liquefaction. Sometimes only a semi- 
 liquid state results, as in the melting of solder, 
 of gelatine and of tar. Almost all matter (ex- 
 cept water between 32 ° and 39 ° Fahrenheit) 
 expands or occupies more space under the action 
 of heat ; but in gases the proportion of expansion 
 is much the greatest. This expansion of gases 
 with heat makes possible the process of ventila- 
 tion by means of an open fire, and is one factor 
 in the rise of dough. 
 
 The solids may also be changed to liquids. Solution. 
 The degree of solubility of any substance de- 
 pends largely upon the temperature of the solv- 
 ent. Common salt dissolves nearly as well in 
 cold as in warm water. "Soda" and alum dis- 
 solve more readily in warm than in cold, while 
 cream of tartar requires hot water for its com- 
 plete solution. 
 
 The amount of solid which water will dissolve Saturation, 
 usually increases with the temperature to a cer- 
 tain degree. After this no more will dissolve 
 and the solution is " saturated." Gases readily 
 dissolve in water, but usually in cold solutions 
 only. 
 
 The action of the liquid is more rapid if the 
 
10 
 
 THE CHEMISTRY OF 
 
 Solvents. 
 
 Swelling. 
 
 solid be first powdered, for a greater area is thus 
 presented to the action of the liquid. It is also 
 usually more rapid when the substance is placed 
 upon or near the surface. Under these condi- 
 tions each particle, while dissolving, is sur- 
 rounded by a thin envelop of syrup, which be- 
 comes heavier and sweeter. The film of syrup 
 sinks into the solvent liquid, so that a clean sur- 
 face is continually exposed to be acted upon. 
 Solution is a valuable agent in bringing about 
 chemical action during many processes of cook- 
 ing and cleaning. 
 
 Water is a nearly universal solvent. It dis- 
 solves larger quantities of more substances than 
 any other liquid. Some solids, however, dissolve 
 more readily in other liquids, as camphor in alco- 
 hol. Silver, copper and tin are not perceptibly 
 dissolved in pure water, while most of their com- 
 pounds, as nitrate of silver and sulphate of cop- 
 per, are thus soluble. Lead dissolves more read- 
 ily in pure water than in that containing some 
 impurities. Gold may be dissolved in a warm 
 mixture of two strong acids. Many of these 
 metallic solutions which may be formed in cook- 
 ing utensils and water pipes are poiscnous, and 
 a knowledge of them becomes a matter of great 
 importance to all housekeepers. 
 
 A process of daily occurrence in the household 
 
COOKING AND CLEANING. 11 
 
 greatly resembles solution. It consists in the 
 taking up of water, which produces an increase 
 of bulk or " swelling," but no true solution. Gel- 
 atine swells in cold water and may then be dis- 
 solved in hot water. Starch "jells" by taking 
 up water; so we soak the cereals which consist 
 largely of starch, that they may be more quickly 
 acted upon by heat. 
 
M 
 
 CHAPTER II. 
 
 Elementary Chemistry. 
 
 OST substances with which we deal in or- 
 dinary life are compounds of two or more 
 elementary constituents. The grain of wheat, 
 the flesh of animals, the dangerous poison, are 
 each capable of separation into simpler sub- 
 stances. Finally a substance is found which can- 
 not be further separated. A chemical clement 
 is a substance which cannot be decomposed into 
 other substances. 
 Elements. Pure gold is an element from which nothing 
 
 can be taken different from itself, but gold coin 
 contains a little copper or silver or both. The 
 oxygen of the air is an element. Air is a mix- 
 ture of two or more elements. Oxygen and 
 hydrogen, both gaseous elements, unite in cer- 
 tain proportions to form the chemical compound, 
 water. 
 
 There are about eighty of these elements 
 known to the chemist, while their compounds 
 are infinite. For his convenience the chemist 
 abbreviates the names of the elements into syn> 
 
COOKING AND CLEANING. 13 
 
 bols, which he uses instead of the names. Usu- 
 ally, the first or the first two letters of the Latin 
 name are taken. These symbols mean much 
 more, however, than time saved, as we shall see. 
 
 Most of the elements unite with each other. Compounds. 
 Then in the resulting compounds, one or more 
 elements may be exchanged for others, so that a 
 multitude of combinations are formed out of few 
 elementary substances. The bulk of our food, 
 clothing and furniture is made up of only five or 
 six of these elements, although about twenty of 
 them enter into the compounds used in the 
 household. The others are found in nature, in 
 the chemical laboratory or in the physician's 
 medicine case. A few are so rare as to be con- 
 sidered curiosities. 
 
 Every housewife should understand something chemical Laws, 
 of these chemical substances — their common 
 forms, their nature and their reactions, that she 
 may not be cheated out of time and money, and, 
 more important still, that she may preserve the 
 health of those for whom she cares. 
 
 All chemical changes are governed by lazvs. 
 Under like conditions, like results follow. No 
 chemical sleight of hand can make one pound of 
 washing soda do the work of two pounds, or one 
 pound of flour make a third more bread at one 
 time than at another, 
 
14 THE CHEMISTRY OF 
 
 Pr<T P oJti<5 l e s finite One °^ tne most important of these laws is 
 that known as the Laiv of Definite Proportions, 
 which states that the various elements do not 
 unite to form chemical compounds in any pro- 
 portions whatever, but only in perfectly definite 
 proportions. From this it follows that to the 
 elements can be assigned values which represent 
 the quantities of them which enter into combina- 
 tion with each other. These values are called 
 the combining weights or atomic weights of the 
 elements, the latter term having been introduced 
 since it is assumed that the elements are built up 
 of extremely small particles of matter called 
 atoms, and that compounds are made of groups 
 of these atoms called molecules, and since under 
 this assumption the relative weights of the ele- 
 ments which unite represent the relative weights 
 of the atoms or multiples of them. Thus, in the 
 compound water, hydrogen and oxygen are 
 present always in perfectly definite proportions, 
 namely, in the relation of one part by weight of 
 hydrogen to eight parts by weight of oxygen ; 
 and in the compound acetylene, the elements 
 carbon and hydrogen are always present in the 
 proportion of one part of hydrogen to twelve 
 parts of carbon. It is customary to adopt as the 
 standard of reference one part by weight of 
 hydrogen and to adopt as the combining weight 
 
COOKING AND CLEANING. 15 
 
 or atomic weight of other elements that quantity 
 of them which combines with one part of hydro- 
 gen, or in some cases with two or more parts of 
 this element. 
 
 Upon this basis the atomic weight of oxygen 
 is sixteen and that of carbon twelve times the 
 atomic weight of hydrogen. The symbol of an 
 element is made to represent its constant atomic 
 weight ; so that, while the word oxygen means 
 only the collection of properties to which is given 
 the name, the symbol O indicates a definite quan- 
 tity of oxygen which is sixteen times the weight 
 of hydrogen represented by the symbol H. 
 
 While it is always true that the elements com- Law of Multiple 
 bine with each other only in definite proportions, 
 yet it is often true that they combine to form two 
 or more definite compounds. Such combinations 
 are governed by the Law of Multiple Propor- 
 tions: When elements form more than one com- 
 pound, they unite according to some multiple of 
 their combining weights. 
 
 Thus, sulphur and oxygen form two difTerent 
 compounds represented by- the symbols S0 2 and 
 S0 3 — where the proportions of sulphur to oxy- 
 gen are thirty-two to thirty-two for the first and 
 thirty-two to forty-eight for the second, the com- 
 bining weight corresponding to the symbol S 
 being thirty-two. 
 
 Proportions. 
 
16 THE CHEMISTRY OF 
 
 A partial list of atomic weights is as follows: 
 
 Element. 
 
 Symbol. 
 
 At. weight. 
 
 Element. Symbol. 
 
 At. weight. 
 
 Aluminum 
 
 Al 
 
 » 27.I 
 
 Magnesium 
 
 Mg 
 
 24.36 
 
 Calcium 
 
 Ca 
 
 40.I 
 
 Nitrogen 
 
 N 
 
 14.04 
 
 Carbon 
 
 C 
 
 I2.0 
 
 Oxygen 
 
 O 
 
 16.O 
 
 Chlorine 
 
 CI 
 
 35-45 
 
 Phosphate 
 
 P 
 
 31.O 
 
 Copper 
 
 Cu 
 
 63.6 
 
 Potassium 
 
 K 
 
 39-15 
 
 Gold 
 
 Au 
 
 197.2 
 
 Radium 
 
 Ra 
 
 225.O 
 
 Hydrogen 
 
 H 
 
 1.008 
 
 Silicon 
 
 Si 
 
 28.4 
 
 Iodine 
 
 I 
 
 126.97 
 
 Silver 
 
 Ag 
 
 I07-93 
 
 Iron 
 
 Fe 
 
 55-9 
 
 Sodium 
 
 Na 
 
 23-05 
 
 Lead 
 
 Pb 
 
 206.9 
 
 Sulphur 
 
 S 
 
 32.06 
 
 Lithium 
 
 Li 
 
 7-03 
 
 Zinc 
 
 Zn 
 
 654 
 
 Symbols. Tri e symbols, then, are the chemist's shorthand 
 
 alphabet, or his sign language. The non-scien- 
 tific reader is apt to look upon the acquisition of 
 this sign language as the schoolboy regards the 
 study of Chinese — as the work of a lifetime. He 
 would be near the truth were he to attempt to 
 remember the symbols of all the complicated 
 compounds known and constantly increasing; 
 but a study of the properties and combinations 
 of the few which make the common substances 
 of daily use need not frighten the most busy 
 
COOKING AND CLEANING. 17 
 
 housewife, for they can be comprehended in a 
 few hours of thoughtful reading. Then a little 
 practice will make them as familiar as the recipe 
 of her favorite cake. "To master the symbolical 
 language of chemistry, so as to fully understand 
 what it expresses, is a great step toward master- 
 ing the science." 
 
 The exchanges and interchanges among the Reactions, 
 elements by which new compounds are produced 
 are called chemical reactions. The written ex- 
 pression of the reaction is called a chemical 
 equation. In all chemical equations there is just 
 as much weight represented on one side of the 
 sign of equality ( = ) as on the other. 
 
 C + 2 = co 2 
 
 12 + 32 = 44 
 Carbon. Oxygen. Carbon Dioxide. 
 
 HC1 + NaOH = NaCl + H 2 
 
 Hydro- Sodium Sodium Water, 
 
 chloric Hydrate. Chloride, 
 
 Acid. or Com- 
 
 mon Salt. 
 
 36.5 + 40 = 58.5 + 18 
 76.5 = 76.5 
 
 This shows that the sum of the weights of 
 the two substances taken is equal to the sum of 
 the weights of the new substances formed as the 
 result of the reaction. 
 
18 THE CHEMISTRY OF 
 
 It is this exactness in dealing with matter 
 which gives to the study of chemistry its great 
 value from an educational standpoint. In the 
 economy of nature nothing is lost. Wood and 
 coal burn in our stoves. The invisible product 
 of their combustion, C0 2 , passes into the air, but 
 adds a definite amount to the weight of the air. 
 Thus the symbol of this product shows that 
 twelve pounds of coal (which when free of ash 
 is nearly pure carbon) in burning take from the 
 air thirty-two pounds of oxygen and give back 
 to the air forty-four pounds of carbon dioxide. 
 
 Similarly the symbol of water, H 2 (atomic 
 weights, H = I, O = 16), shows that for every 
 eighteen parts by weight of water produced, 
 there will be two parts by weight of H and six- 
 teen parts by weight of O required. 
 
 Although the phenomena themselves are found 
 to be unchangeable, our explanation of them may 
 be modified as our knowledge increases. 
 
 Present theories penetrate only a little into the 
 real essence of things, and the investigator soon 
 stumbles upon questions whose explanation does 
 not at present even seem to be a possibility. 
 
 (See late text-books on chemistry for the dif- 
 ference between ions and atoms.) 
 Oxidation. One of the most important chemical changes 
 
 that takes place inside or outside the animal body 
 
COOKING AND CLEANING. 10 
 
 is that union of oxygen (four-fifths of the air) 
 with carbon or hydrogen which we call oxida- 
 tion — under. the steam boiler and in the stove it 
 is called combustion. It is the chief source of 
 available power or energy in either case. (See 
 pp. 25, 26.) 
 
 The same amount of heat is evolved when a 
 given amount of. substance is oxidized, whether 
 the combustion takes place slowly or rapidly. 
 
 An appreciation of these fundamental laws of The 
 
 i-i 1 • • 11 »• 1 Calorimeter. 
 
 chemical combination is needed to realize the 
 significance of the recent work on the use of 
 food in the human body as demonstrated in the 
 calorimeter. 
 
 Before a study of the chemical composition of 
 food materials and of the chemical and physical 
 changes occurring in the processes of cooking 
 as a preparation for the best utilization of these 
 food stuffs could be insisted upon, it was neces- 
 sary to be convinced that the utilization of the 
 chemical compounds, such as sugar, starch, albu- 
 min, etc., was the same in effect within the body 
 as without, in stove or furnace. 
 
 For the proof that the law of the conserva- 
 tion of energy held in the life processes going 
 on in the human body, an examination of the 
 food and of the results of its consumption was 
 imperative. 
 
20 THE CHEMISTRY OF 
 
 For this purpose a " respiration calorimeter" 
 was set-up.* 
 
 "This is a metal-walled chamber in which- a 
 man lives, eats, drinks, works and sleeps. Pro- 
 vision is made for ventilating the chamber and 
 for regulating the temperature and moisture of 
 the air within it. The volume of the ventilating 
 air current is measured and samples for analysis 
 are taken before and after it passes through the 
 chamber, thus obtaining the amounts of carbon 
 dioxide and water in the respiratory products. 
 The food, drink, feces and urine are weighed 
 and analyzed, and their potential energy is deter- 
 mined, as is the kinetic energy given off from the 
 body in the forms of heat and external muscular 
 work. 
 
 "The devices for measuring the heat or loss 
 of heat given off from the body include : ( I ) 
 Arrangements to prevent gain or loss of heat 
 in the chamber either by the passage of heat 
 through the walls or the bringing in and taking 
 out of heat in the ventilating air current; (2) 
 arrangements by which the heat given off in the 
 chamber, by the body or otherwise, is carried 
 out by a current of water. . . . This current, 
 which is conveyed by copper pipes, comes into 
 the chamber at a low temperature, passes around 
 the interior, absorbs the heat, and goes out cor- 
 respondingly warmer. The quantity of the water 
 and the rise of temperature show how much heat 
 is carried out." 
 
 *" Description of a New Respiration Calorimeter and Experiments on 
 the Conservation of Energy in the Human Body," by W. O. Atwater, Ph.D; ; 
 Professor of Chemistry, Wesleyan University, and E. B. Rose, Ph.D., Pro- 
 fessor of Physics, Wesleyan University. 
 
COOKING AND CLEANING. 21 
 
 By means of such apparatus there may be de- J/^jg 11 Value 
 termined questions pertaining to the demands Ex P erim ents. 
 of the body for nutriment under different condi- 
 tions of work and rest ; the duties performed by 
 the different nutrients of food in supplying the 
 needs of the body; and finally the nutritive 
 values of food materials and the amount and 
 proportions best adapted to the needs of people 
 of different classes, with different occupations 
 and in different conditions of life. 
 
 By experiment it has been found that I gram 
 of carbohydrates (starch, sugar, etc.) or proteids 
 (lean meat, white of egg, etc.) gives on an aver- 
 age about 4.1 calories,* and one gram of fats 9.3 
 calories. Therefore to find the value of a given 
 dish set upon the family table is simple when 
 the weights of the ingredients are known. For 
 instance, in a curry stew with rice, three pounds 
 of medium fat beef will yield 259 grams proteid 
 and 175 grams of fat, while ten ounces of rice 
 will yield 22.5 grams proteid, 1 gram of fat and 
 222 grams of carbohydrates. Adding together 
 the carbohydrate and proteid gives 503.5 grams. 
 Multiplying this number by the 4.1 calories per 
 gram we have 2,064 calories; while multiplying 
 the 176 grams of fat by 9.3 gives 1,636 calories 
 for the fat, a total of 3,700 calories, or as many 
 
 * For definition of calories, see page 47. 
 
22 THE CHEMISTRY OF 
 
 as should be supplied by a dinner for three 
 working men. 
 
 The housewife well understands that she may 
 provide sufficient food, but that she cannot be 
 sure it will be eaten, or assimilated if it is eaten. 
 But she must also understand that power does 
 not come from nothing, and that if sufficient 
 nourishment is not provided, the body cannot 
 have its full due. 
 iwifrs One °^ ^ le un i versa l chemical operations in 
 
 the household is the use of cream of tartar and 
 baking soda or of baking powders. Advantage 
 has been taken of this fact to put upon the 
 market many substitutes and variations with the 
 natural result that the housewife is confused and 
 uncertain. The table on page 23 may be helpful 
 in clearing up some of the mysterious ways of 
 the substances themselves and of their advocates. 
 
 Thus, 84 parts of cooking soda unite with 188 
 parts of cream of tartar — if both are pure — to 
 give 44 parts of the gas C0 2 . Cream of tartar 
 is a compact powder, however, so that a tea- 
 spoonful will weigh more than a teaspoonful of 
 soda, and illustrates the difference in accuracy 
 between weighing and measuring. Because 
 cream of tartar is so liable to cake, a starch is 
 added to the mixing for baking powder. For 
 home preparation 5 to 10 per cent will be enough. 
 
COOKING AND CLEANING. 23 
 
 §x|l§ 
 
 « 53 + + + + 
 
 CO ^"^ 
 
 4 S S K ~ Ph 
 
 + o o 
 
 o i x K 
 
 CI 
 
 ,- O k ffi js w , 
 
 8 » B Si ! s * 
 
 I + * Q + 5 
 
 
 o 
 
 a 
 
 + 1-H K> C/2 . w OO 
 
 %** Ui l*i i ! 
 
 £ o ^ o 
 
 ^X © ^°° -3 
 
 K w ffi X o 
 
 <0 * 
 
CHAPTER III. 
 
 Living and 
 
 Lifeless 
 
 Matter. 
 
 Chemical 
 Change 
 Produces 
 Heat. 
 
 Starches, Sugars, Fats, Their Preparation for Food. 
 
 THE material world is divided into living and 
 lifeless matter. All living matter requires 
 food that it may grow, repair waste, and reproduce 
 itself, if the existence of its kind is to be continued. 
 This food must be made from the material elements 
 we have been studying. Food for the human body 
 must, therefore, contain such elements, in com- 
 bination, as are found in the body substance, in 
 order that new materials may be formed from 
 them by the processes of life. 
 
 Wherever there is life, there is chemical change, 
 and, as a rule, a certain degree of heat is neces- 
 sary, in order that chemical change may occur. 
 Vegetation does not begin in the colder climates 
 until the air becomes warmed by the heat of the 
 spring. When the cold of w T inter comes upon 
 the land, vegetation ceases. If plant life is to be 
 sustained during a northern winter, artificial 
 warmth must be supplied. This is done by heat 
 from a furnace or stove. In chemical terms, car- 
 bon and hydrogen from coal, wood, or gas are 
 caused to unite with the oxygen of the air to form 
 carbon dioxide (carbonic acid gas) and water, and 
 
COOKING AND CLEANING. 25 , 
 
 by this union of two elements with oxygen, heat 
 is produced. 
 
 c +o 2 =c o 2 
 
 C H 4 +O4 =C 2 +2H 2 O 
 
 These two chemical reactions indicate the Combustion, 
 changes which cause the production of artificial 
 heat generally used for domestic purposes. All 
 living matter, whether plant or animal, is found 
 by analysis to contain carbon, oxygen, hydrogen, 
 and nitrogen. Other elements are present in small 
 and varying quantities, but "the great four" are 
 the essentials. The plant is able to take all its 
 food elements from air, water and soil, and, in 
 its own cells, to manufacture those compounds 
 upon which it can feed ; while an animal cannot do 
 this, but must accept for the most part the manu- 
 factured product of the plant. Man, therefore, 
 finds his food in both vegetable and animal sub- 
 stances. 
 
 Since many animals live in temperatures in 
 which plants would die, it is evident that they must 
 have some source of heat in themselves. This is 
 found in the union of the oxygen of the air 
 breathed, with carbonaceous matter eaten as food, 
 and the formation of carbonic acid gas (carbon 
 dioxide), and water (C0 2 and H 2 0), just as 
 in the case of the combustion of the wood in the 
 grate. Only, instead of this union taking place in 
 
26 
 
 THE CHEMISTRY OF 
 
 Vital Tem- 
 perature. 
 
 Food Elements 
 for Combus- 
 tion. 
 
 Oxygen. 
 
 one spot, and so rapidly as to be accompanied by 
 light, as in the case of the grate fire, it takes place 
 slowly and continuously in each living cell. 
 Nevertheless, the chemical reaction seems to be 
 identical. 
 
 The heat of the human body must be main- 
 tained at 37 C — the temperature necessary for 
 the best performance of the normal functions. Any 
 continued variation from this degree of heat indi- 
 cates disease. Especially important is it that there 
 be no considerable lowering of this temperature, 
 for a fall of one degree is dangerous. 
 
 The first requirement of animal life is, then, the 
 food which supplies the heat necessary for the 
 other chemical changes to take place. The class 
 of foods which will be considered here as those 
 utilized for the production of animal heat among 
 other functions, includes the carbon compounds, 
 chiefly composed of carbon, hydrogen and oxygen. 
 
 The slow combustion or oxidation of these car- 
 bonaceous bodies cannot take place without an 
 abundance of oxygen; hence, the diet of the ani- 
 mal must include fresh air — a point too often over- 
 looked. The amount of oxygen, by weight, taken 
 in daily, is equal to the sum of all the other food 
 elements. One-half of these consists of some form 
 of starch or sugar — the so-called carbohydrates, 
 
COOKING AND CLEANING. 27 
 
 in which the hydrogen and oxygen are found in 
 the same proportions as in water. (The fats will 
 be considered by themselves.) 
 
 Starches, sugars and gums are among the con- starches, 
 stituents of plants, and are sometimes found in 
 animals in small quantities. Starch is found in 
 greater or less abundance in all plants and is laid 
 up in large quantities in the seeds of many species. 
 Rice is nearly pure starch, wheat and the other 
 cereals contain sixty to seventy per cent of it. 
 Some tubers contain it, as potatoes, although in 
 less quantity, ten to twenty per cent. It is formed 
 by means of the living plant-cell and the sun's 
 rays, from the carbon dioxide and water contained 
 in the air, and it is the end of the plant life — the 
 stored energy of the summer, prepared for the 
 early life of the young plant another year. An 
 allied substance is called cellulose. This oc- 
 curs under numerous forms, in the shells 
 and skins of fruits, in their membraneous 
 partitions, and in the cell walls. Starch in its com- 
 mon forms is insoluble in water. It dissolves par- 
 tially in boiling water, forming a transparent jelly 
 when cooled. 
 
 Sugars, also, are a direct or indirect product of sugars, 
 plant life. Common sugar, or cane-sugar, occurs 
 in the juices of a few grasses, as the sugar-cane; 
 of some trees; and of some roots. Milk-sugar is 
 
28 THE CHEMISTRY OF 
 
 found in the milk of mammalia, while grape-sugar 
 is a product of the ripening processes in fruit. 
 Solution 11 " Digestion is primarily synonymous with solu- 
 
 tion. All solid food materials must become prac- 
 tically soluble before they can pass through the 
 walls of the digestive system. As a rule, non-crys- 
 talline bodies are not diffusible, so that starch and 
 like materials must be transformed into soluble, 
 crystalline substances, before absorption can take 
 place. Cane-sugar, too, has to undergo a chemical 
 change before it can be absorbed; but grape and 
 milk sugars are taken directly into the circula- 
 tion. To this fact is due a part of the great nu- 
 tritive value of dried fruits as raisins, dates and 
 figs, and the value of milk-sugar over cane-sugar, 
 for children or invalids. Chemically pure milk- 
 sugar can now be obtained at wholesale for about 
 35 cents per pound. This may be used in certain 
 diseases when cane-sugar is harmful. The chemi- 
 cal transformations of starch and sugar have been 
 very carefully and scientifically studied with refer- 
 ence to brewing and wine-making. Several of the 
 operations concerned necessitate great precision in 
 respect to temperature and length of time, and 
 these operations bear a close analogy to the 
 process of bread-making by means of yeast. The 
 general principles on which the conversion of 
 starch into sugar, and sugar into alcohol, are con- 
 
COOKING AND CLEANING. 29 
 
 ducted will therefore be stated as preliminary to a 
 discussion of starch and sugar as food. 
 
 There are two distinct means known to the starch Con- 
 
 version. 
 
 chemist, by which this change can be produced. 
 One is by the use of acid and heat, which changes 
 the starch into sugar, but can go no farther. The 
 other is by the use of a class of substances called 
 ferments, some of which have the power of chang- 
 ing the starch into sugar, and others of changing 
 the sugar into alcohol and carbon dioxide. These 
 ferments are in great variety and the seeds of 
 some of them are always present in the air. Among 
 the chemical substances called ferments, one is 
 formed in sprouting grain which is called diastase 
 or starch converter, which first, under the in- 
 fluence of warmth, changes the starch into a sugar, 
 as is seen in the preparation of malt for brewing. 
 The starch (C 6 H 10 O 5 ), first takes up water (H 2 0), 
 and, under the influence of the ferment, is changed 
 into maltose. Cane-sugar is readily converted 
 into two sugars, dextrose and levulose, belonging 
 to the glucoses. 
 
 Ci, H 22 On +H 2 O +ferment=2Ce <H ia O c 
 
 Cane-Sugar. Water. Dextrose and Levulose. 
 
 Glucose and maltose are converted by yeast into Sugar 
 
 Conversion. 
 
 alcohol and carbon dioxide. In beer, the alcohol 
 is the product desired, but in bread-making the 
 
30 THE CHEMISTRY OF 
 
 chief object of the fermentation is to produce car- 
 bon dioxide to puff up the bread, while the al- 
 cohol escapes in the baking. 
 
 {2C, H 6 O 
 Alcohol. 
 2C 2 
 Carbon Dioxide. 
 
 Ce 
 
 Dextrose 
 
 The alcohol, if burned, would give carbon dioxide 
 and water. 
 
 2C 2 H 6 O +12O =4C 2 +6H2 O. 
 
 Alcohol. Oxygen. Carbon Dioxide. Water. 
 
 It will be seen, from the previous equations, 
 that nothing has been lost during the process. 
 The six atoms of carbon in the original starch 
 reappear in the carbon dioxide at the end, 
 2C0 2 -r-4C0 2 . Two atoms of hydrogen from the 
 water, and thirteen atoms of oxygen from the 
 water and the air have been added. Reckoning 
 the atomic weights of the starch used, the carbon 
 dioxide and the water formed, we find that, in 
 round numbers, sixteen pounds of starch will yield 
 twenty-six pounds of gas and ten pounds of water, 
 or more than double the weight of the starch. 
 These products of decomposition are given back 
 to the air in the same form in which those sub- 
 stances existed from which the starch was orig- 
 inally formed. 
 i?th V e ersion The same cycle of chemical changes goes on in 
 
 Digestive ^ h uman body when starchy substances are 
 
COOKING AND CLEANING. 31 
 
 taken as food. Such food, moistened and warmed 
 in the mouth, becomes mixed with air through 
 mastication, by reason of the property of the sa- 
 liva to form froth, and also becomes impregnated 
 with ptyalin, a substance which can change starch 
 into sugar as can the diastase of the malt. The 
 mass then passes into the stomach, and the 
 change, once begun, goes on. As soon as the 
 sugar is formed, it is absorbed into the circu- 
 latory system and, by the life processes, is oxi- 
 dized, i. e., united with more oxygen and changed 
 finally into carbon dioxide and water. 
 
 No starch is utilized in the human system as 
 starch. It must undergo transformation before it 
 can be absorbed. Therefore starchy foods must 
 not be given to children before the secretion of 
 the starch converting ferments has begun, nor to 
 any one in any disease where the normal action of 
 the glands secreting these ferments is interrupted. 
 Whatever starch passes out of the stomach 
 unchanged, meets a very active converter in 
 the intestinal juice. If grains of starch escape 
 these two agents, they leave the system in the 
 same form as that in which they entered it. 
 
 Early man, probably, lived much like the beasts, 
 taking his food in a raw state. Civilized man re- 
 quires much of the raw material to be changed, by 
 the action of heat, into substances more palatable 
 and already partly digested. 
 
32 THE CHEMISTRY OF 
 
 The chemistry of cooking the raw materials is 
 very simple. It is in the mixing of incongruous 
 materials in one dish or one meal that complica- 
 tion arises. 
 5 h sur°ch king Since fully one-half of our food is made up of 
 
 starches and sugars, it is pertinent to examine, 
 beside their chemical composition, the changes 
 which they may undergo in the processes of cook- 
 ing that can render them more valuable as food, 
 or which, on the other hand, may in large meas- 
 ure destroy their food value. 
 
 The cooking of starch, as rice, farina, etc., re- 
 quires little explanation. The starch grains are 
 prepared by the plant to keep during a season of 
 cold or drought and are very close and compact; 
 they need to be swollen and distended by moisture 
 in order that the chemical change may take place 
 readily, as it is a law, that the finer the particles, 
 the sooner a given change takes place, as has 
 been explained in a previous chapter. Starch 
 grains may increase to twenty-five times their bulk 
 during the process of hydration. 
 
 The cooking of the potato and other starch-con- 
 taining vegetables, is likewise a mechanical proc- 
 ess very necessary as a preparation for the chem- 
 ical action of digestion; for raw starch has been 
 shown to require a far longer time and more di- 
 gestive power than cooked starch. Change takes 
 
COOKING AND CLEANING. 33 
 
 place slowly, even with thorough mastication, un- 
 less the starch is heated and swollen, and, in case 
 the intestinal secretion is disturbed, the starch 
 may not become converted at all. 
 
 The most important of all the articles of diet Bread, 
 which can be classed under the head of starchy 
 foods is bread. Wheat bread is not all starch, but 
 it contains a larger percentage of starch than of 
 anything else, and it must be discussed under this 
 topic. Bread of some kind has been used by man- 
 kind from the first dawn of civilization. During 
 the earlier stages, it consisted chiefly of powdered 
 meal and water, baked in the sun, or on hot 
 stones. This kind of bread had the same charac- 
 teristics as the modern sea-biscuit, crackers and 
 hoe-cake, as far as digestibility was concerned. It 
 had great density, it was difficult to masticate, 
 and the starch in it presented but little more sur- 
 face to the digestive fluids than that in the hard 
 compact grain, the seed of the plant. 
 
 Experience must have taught the semi-civilized 
 man that a light porous loaf was more digestible 
 than a dense one. Probably some dough was ac- 
 cidentally left over, yeast plants settled upon it 
 from the air, fermentation set in, and the possibil- 
 ity of porous bread was thus suggested. 
 
 The small loaf, light, spongy, with a crispness 
 and sweet, pleasant taste, is not only aesthetically, 
 
34 THE CHEMISTRY OF 
 
 but chemically, considered the best form in which 
 starch can be presented to the digestive organs. 
 The porous condition is desired in order that as 
 large a surface as possible shall be presented to 
 the action of the chemical converter, the ptyalin 
 of the saliva, and, later, to other digestive fer- 
 ments. There is also a better aeration in the proc- 
 ess of mastication. 
 
 The ideal bread for daily use should fulfill cer- 
 tain dietetic conditions : 
 
 i. It should retain as much as possible of the 
 nutritive principles of the grain from which it is 
 made. 
 
 2. It should be prepared in such a manner as to 
 secure the complete assimilation of these nutri- 
 tive principles. 
 
 3. It should be light and porous, so as to allow 
 the digestive juices to penetrate it quickly and 
 thoroughly. 
 
 4. It should be especially palatable, so that one 
 may be induced to eat enough for nourishment. 
 
 5. It should be nearly or quite free from coarse 
 bran, which causes too rapid muscular action to 
 allow of complete digestion. This effect is also 
 produced when the bread is sour. 
 
 Ordinary Graham bread, brown bread and the 
 black bread of Germany fulfill conditions 1 and 4, 
 but fail in the other three. Bakers' bread of fine 
 
COOKING AND CLEANING. 35 
 
 white flour fulfills 2, 3 and 5, but fails in the other 
 two. Home-made bread often fulfills conditions 
 4 and 5, but fails in the other three. 
 
 Very early in the history of the human race Y^f. n ° r 
 leavened bread seems to have been used. This was 
 made by allowing flour and water to stand in a 
 warm place until fermentation had well set in. A 
 portion of this dough was used to start the process 
 anew in fresh portions of flour and water. This 
 kind of bread had to be made with great care, for 
 germs different from yeast might get in, forming 
 lactic acid — the acid of sour milk — and other sub- 
 stances unpleasant to the taste and harmful to the 
 digestion. 
 
 Butyric acid occurs in rancid butter and in many 
 putrified organic substances. A sponge made from 
 perfectly pure yeast and kept pure may stand for a 
 long time after it is ready for the oven and still 
 show no sign of sourness. 
 
 On account of the disagreeable taste of leaven 
 and because of the possibility that the dough might 
 reach the stage of putrid fermentation, chemists 
 and physicians sought for some other means of 
 rendering the bread light and porous. The search 
 began almost as soon as chemistry was worthy the 
 name of a science, and one of the early patents 
 bears the date 1837. Much time and thought have 
 been devoted to the perfecting of unfer- 
 
36 THE CHEMISTRY OF 
 
 merited bread; but since the process of beer- 
 making has been universally introduced, yeast has 
 been readily obtained, and is an effectual means of 
 giving to the bread a porous character and a pleas- 
 ant taste. Since the chemistry of the yeast fer- 
 mentation has been better understood, a change of 
 opinion has come about, and nearly all scientific 
 and medical men now recommend fermented bread. 
 The bacteriology of bread and bread-making is 
 yet somewhat obscure. The ordinary yeasts are so 
 mingled with bacteria that the part which each 
 plays is not yet understood. Only experiments 
 long continued will solve these problems. 
 S^°S Re " The chemical reactions concerned in bread- 
 
 raising are similar to those in beer-making. To 
 the flour and warmed water is added yeast, a mi- 
 croscopic plant, capable of causing the alcoholic 
 fermentation. The yeast begins to act at once, but 
 slowly; more rapidly if sugar has been added and 
 the dough is a semi-fluid. Without the addition 
 of sugar no change is evident to the eye for some 
 hours, as the fermentation of sugar from starch, by 
 the diastase, gives rise to no gaseous products. As 
 soon as the sugar is decomposed by the yeast plant 
 into alcohol and carbonic acid gas (carbon diox- 
 ide), the latter product makes itself known by the 
 bubbles which appear and the consequent swelling 
 of the whole mass. 
 
 actions in 
 
 Bread-Mak. 
 
 ing. 
 
COOKING AND CLEANING. 37 
 
 It is the carbon dioxide which causes the sponge- 
 like condition of the loaf by reason of the peculiar 
 tenacity of the gluten, one of the constituents of 
 wheat. It is a well-known fact that no other kind 
 of grain will make so light a bread as wheat. It is 
 the right proportion of gluten (a nitrogenous sub- 
 stance to be considered later) which enables the 
 light loaf to be made of wheat flour. 
 
 The production of carbon dioxide is the end of 
 the chemical process. The rest is purely mechanical. 
 The kneading is for the purpose of rendering the 
 dough elastic by the spreading out of the already 
 fermented mass and its thorough incorporation 
 with the fresh flour. Another reason for kneading 
 is, that the bubbles of gas may be broken up into 
 as small portions as possible, in order that there 
 may be no large holes, only very fine ones, 
 evenly distributed through the loaf, when it is 
 baked. 
 
 The temperature at which the dough should be Temperature 
 maintained during the chemical process is an im- Making, 
 portant point. If the characteristics of "home- 
 made" bread are desired, it is found to be better to 
 use a small amount of yeast and to keep the dough 
 at a temperature from 55 degrees to 60 degrees for 
 twelve to fifteen hours, than to use a larger quantity 
 of yeast and to cause its rapid growth. The changes 
 which produce the desired effect are not fully under- 
 
38 THE CHEMISTRY OF 
 
 stood. Above 90 degrees the production of acetic 
 acid — the acid of vinegar — is liable to occur: for 
 this temperature, while unfavorable for the yeast 
 plant, is favorable for the growth of the particular 
 bacterium which produces acetic acid. 
 
 C 2 H 6 O +0 2 =C 2 H 4 2 +H 2 O 
 
 Alcohol. Acetic Water. 
 
 Acid. 
 
 After the dough is stiffened by a little fresh flour 
 and is nearly ready for the oven, the temperature 
 may be raised, for a few minutes, to 100 degrees 
 or 165 degrees F. The rapid change in the yeast is 
 soon stopped by the heat of the oven. 
 Bailng ' The baking of the loaf has for its object to kill 
 
 the ferment, to heat the starch sufficiently to render 
 it easily soluble, to expand the carbon dioxide and 
 drive off the alcohol, to stiffen the gluten, and to 
 form a crust which shall have a pleasant flavor. 
 The oven must be hot enough to raise the tempera- 
 ture of the inside of the loaf to 212 degrees F., or 
 the bacteria will not all be killed. A pound 
 loaf, four inches by four by nine, may 
 be baked three-quarters of an hour in an 
 oven where the initial temperature is 400 
 degrees F., or for an hour and a half, where 
 the temperature during the time does not rise above 
 350 degrees F. Quick baking gives a white loaf, 
 because the starch has undergone but little change. 
 
COOKING AND CLEANING. 39 
 
 The long, slow baking gives a yellow tint, with the 
 desirable nutty flavor, and crisp crust Different 
 flavors in bread are supposed to be caused by the 
 different varieties of yeast used or by bacteria, 
 which are present in all doughs, as ordinarily 
 prepared. 
 
 The brown coloration of the crust, which gives 
 a peculiar flavor to the loaf, is caused by the forma- 
 tion of substances analogous to dextrine and cara- 
 mel, due to the high heat to which the starch is 
 subjected. 
 
 One hundred pounds of flour are said to make 
 from 126 to 150 pounds of bread. This increase of 
 weight is due to the incorporation of water, pos- 
 sibly by a chemical union, as the water does not 
 dry out of the loaf, as it does out of a sponge. The 
 bread seems moist when first taken from the oven, 
 and dry after standing some hours, but the weight 
 will be found nearly the same. It is this probable 
 chemical change which makes the difference, to 
 delicate stomachs, between fresh bread and stale. A 
 thick loaf is best when eaten after it is twenty-four 
 hours old, although it is said to be "done" when 
 ten hours have passed. Thin biscuits do not show 
 the same ill effects when eaten hot. The bread 
 must be well baked in any case, in order that the 
 process of fermentation may be stopped. If this be 
 stopped and the mastication be thorough, so that 
 
40 
 
 THE CHEMISTRY OF 
 
 Expansion of 
 Water into 
 Steam. 
 
 Methods of 
 Obtaining i 
 
 Carbon dioxide. 
 
 the bread is in finely divided portions instead of in 
 a mass or ball, the digestibility of fresh and stale 
 bread is about the same. 
 
 The expansion of water or ice into seventeen 
 hundred times its volume of steam is sometimes 
 taken advantage of in making snow-bread, water- 
 gems, etc. It plays a part in the lightening of 
 pastry and crackers. Air, at 70 degrees, doubles 
 its volume at a temperature of 560 F., so that if air 
 is entangled in a mass of dough, it gives a certain 
 lightness when the whole is baked. This is the 
 cause of the sponginess of cakes made with eggs. 
 The viscous albumen catches the air and holds it, 
 even when it is expanded, unless the oven is too 
 hot, when the sudden expansion is liable to burst 
 the bubbles and the cake falls. 
 
 As has been said, the production of the porous 
 condition, by means of carbon dioxide, generated 
 in some other way than by the decomposition of 
 starch, was the study of practical chemists for some 
 years. 
 
 A simple method for obtaining the carbon diox- 
 ide is by heating bicarbonate of sodium. 
 
 2Na H C O3 +heat = Na 2 C Os -fH 2 O +C O, 
 
 The bicarbonate splits up into sodium carbonate, 
 water, and carbon dioxide. The bread is light but 
 yellow. Some of the carbonate remains in the 
 
COOKING AND CLEANING. 41 
 
 bread, and as it neutralizes the acid of the gastric 
 juice, digestion may be retarded. It also acts upon 
 the gluten producing an unpleasant odor. 
 
 Among the first methods proposed was one un- 
 doubtedly the best theoretically, but very difficult 
 to put in practice, viz., the liberation of carbon 
 dioxide from bicarbonate of sodium by means of 
 muriatic acid. 
 
 Na H C 3 +H CI =Na CI +H 2 O +C 2 
 
 " Soda." Hydrochloric Common Water. Carbon dioxide. 
 
 Acid. Salt. 
 
 This liberation of gas is instantaneous on the con- 
 tact of the acid with the "soda," and only a skilled 
 hand can mix the bread and place it in the oven 
 without the loss of much of the gas. Tartaric acid, 
 the acid phosphates, sour milk (lactic acid), vinegar 
 (acetic acid), alum — ail of which have been used — 
 are open to the same objection. Cream of tartar 
 is the only acid substance commonly used which 
 does not liberate the gas by simple contact when 
 cold. It unites with "soda" only when heated, be- 
 cause it is so slightly soluble in cold water. For the 
 even distribution of the gas by thorough mixing, 
 cream of tartar would seem to be the best ; but as, 
 beside gas, there are other products which remain 
 behind in the bread in the case of all the so-called 
 baking powders, the healthfulness of these residues 
 must be considered. 
 
42 THE CHEMISTRY OF 
 
 Common salt is the safest, and perhaps the resi- 
 dues from acid phosphate are next in order. 
 
 The tartrate, lactate and acetate of sodium are 
 not known to be especially hurtful. As the im- 
 portant constituent of Seidlitz powders is Rochelle 
 salt, the same compound as that resulting from the 
 use of cream of tartar and "soda," it is not likely to 
 be very deleterious, taken in the small quantities 
 in which even habitual "soda biscuit'' eaters take it. 
 products ^ ie var i° us products formed by the chemical de- 
 
 composition of alum and "soda" are possibly the 
 most injurious, as the sulphates are supposed to be 
 the least readily absorbed salts. Taking into con- 
 sideration the advantage given by the insolubility 
 of cream of tartar in cold water, and the compara- 
 tively little danger from its derivative — Rochelle 
 salt — it would seem to be, on the whole, the best 
 substance to add to the soda in order to liberate 
 the gas; but the proportions should be chemically 
 exact, in order that there be no excess of alkali to 
 hinder digestion. Hence, baking powders pre- 
 pared by weight and carefully mixed, are a great 
 improvement over cream of tartar and "soda" 
 measured separately. As commonly used, the 
 proportion of soda should be a little less than 
 half. The table on page 23 gives the chemical re- 
 actions of the more common baking powders. 
 
COOKING AND CLEANING. 
 
 43 
 
 Fats. 
 
 Another group of substances which, by their 
 slow combustion or oxidation in the animal body, 
 yield carbon dioxide and water and furnish heat 
 to the system, is called fats. These comprise the 
 animal fats — suet, lard, butter, etc. — and the vege- 
 table oils — olive oil, cottonseed oil, the oily matter 
 in corn, oats, etc. 
 
 Fats, ordinarily so called, are simply solidified 
 oils, and oils are liquid fats. The difference be- 
 tween them is one of temperature only ; for, within 
 the body, all are fluid. In this fluid condition, they 
 are held in little cells which make up the fatty 
 tissues. 
 
 These fatty materials all have a similar composi- 
 tion, containing, when pure, only carbon, hydro- 
 gen, and oxygen. They differ from starch and 
 sugar in the proportion of oxygen to the carbon 
 and hydrogen, there being very little oxygen rela- 
 tively in the fatty group, hence more must be 
 taken from the air for their combustion. 
 
 Composition 
 of Fats. 
 
 Cl8 H36 O2 
 
 Stearic Acid in Suet. 
 
 Ce H10 Os 
 
 Starch. 
 
 One pound of starch requires one and two-tenths 
 pounds of oxygen, while one pound of suet re- 
 quires about three pounds of oxygen for perfect 
 combustion. This combination of oxygen with the 
 
 Combustion 
 of Fats. 
 
44 THE CHEMISTRY OF 
 
 excess of hydrogen, as well as with the excess of 
 carbon results in a greater quantity of heat from 
 fat, pound for pound, than can be obtained from 
 starch or sugar. Recent experiments have proved 
 that the fats yield more than twice as much heat as 
 the carbohydrates; hence people in Arctic regions 
 require large amounts of fat, and, everywhere, the 
 diet of winter should contain more fat than that of 
 summer. 
 Sources of While the chemical expression of these changes 
 
 is that of heat produced, it must be remembered 
 that energy or work done by the body is included, 
 and that both fats and carbohydrates are the source 
 of this energy, and that they must be increased in 
 proportion as the mechanical work of the body in- 
 creases. If a quantity is taken at any one time 
 greater than the body needs for its work, the sur- 
 plus will be deposited as a bank account, to be 
 drawn from in case of any lack in the future supply 
 of either. 
 
 This double source of energy has a large 
 economic value, for it has been noticed that in com- 
 munities where fats are dear, the required amount 
 of heat-giving and energy-producing food is made 
 up by a larger proportion of the cheaper carbo- 
 hydrates. This prevents too large a draft on the 
 bank account. It has also been noticed that wage- 
 earners do use a large proportion of fat, whenever 
 it is within their means, 
 
COOKING AND CLEANING. 45 
 
 Numerous investigations into the condition of ?a t c " s t he of 
 the insane, as well as of the criminal classes, show Diet - 
 the results of too little nutrition and the absence of 
 sufficient fat. The diet of school children should 
 be carefully regulated with the fat supply in view. 
 Girls, especially, show, at times, a dislike to fat and 
 an overfondness for sugar. They should have the 
 proper proportion of fat furnished by butter, cream, 
 or, if need be, in disguised form. The cook must 
 remember that the butter absorbed from her cake 
 tin or the olive oil on her salad is food, as well as 
 the flour and eggs. 
 
 The essential oils, although very important, as 
 will be shown in the chapter on flavors, occur in 
 such small quantities that they need not be con- 
 sidered here, except by way of caution. These oils 
 are all volatile, and, therefore, will be dissipated by 
 a high temperature. 
 
 The digestion of fats is mainly a process of emul- 
 sion. With the intestinal fluids, the bile, especially, 
 the fats form an emulsion in which the globules 
 are finely divided, and rendered capable of passing 
 through the membranes into the circulatory sys- 
 tem. The change, if any, is not one destructive 
 of the properties of the fatty matters. 
 
 If we define cooking as the application of heat, The Digestion 
 then whatever we do to fats in the line of cooking 
 them is liable to hinder rather than help their diges- 
 
 of Fat. 
 
46 COOKING AND CLEANING. 
 
 tibility. The flavor which cooking gives to food 
 materials containing fat is, in general, due not to 
 any flavor of the fat but to substances produced 
 in the surrounding tissues. 
 hs'S'toii- ^ ats ma y ^ e heated to a temperature far above 
 
 Fats ture ° n *^at of boiling water without showing any change ; 
 
 but there comes a point, different for each fat, 
 where reactions take place, the products of which 
 irritate the mucous membranes and, therefore, in- 
 terfere with digestion. It is the volatile products of 
 such decomposition which cause the familiar action 
 upon the eyes and throat during the process of 
 frying, and, also, the tell-tale odors throughout the 
 house. The indigestibility of fatty foods, or foods 
 cooked in fat, is due to these harmful substances 
 produced by the too high temperature. It must 
 not be inferred from what has been said that the 
 oxidation of starch and fat is the only source of 
 heat in the animal body. A certain quantity is un- 
 doubtedly derived from the chemical changes of 
 the other portions of food, but the chemistry of 
 these changes is not yet fully understood. 
 
CHAPTER IV. 
 
 Nitrogenous Constituents. 
 
 THE animal body is a living machine, capable 
 of doing work — raising weights, pulling loads, 
 and the like. The work of this kind which it does 
 can be measured by the same standard as the work 
 of any machine, i. e., by the mechanical unit of 
 energy — the foot-ton. 
 
 The power to do mechanical work comes from 
 the consumption of fuel, — the burning of wood, 
 coal or gas; and this potential energy of fuel is often 
 expressed in units of heat or calories, a calorie being 
 nearly the amount of heat required to raise two 
 quarts of water one degree Fahrenheit. The ani- 
 mal body also requires its fuel, namely food, in 
 order to do other work — its thinking, its talking or 
 even its worrying. 
 
 The animal body is more than a machine. It 
 requires fuel to enable it not only to zvork but also 
 to live, even without working. About one-third of 
 the food eaten goes to maintain its life, for while 
 the inanimate machine is sent periodically to the 
 repair-shop, the living machine must do its own 
 
 Animal P>< dy 
 a Machint. 
 
 Calories. 
 
 Need of Body 
 Fuel. 
 
Waste-Re- 
 pair. 
 
 48 THE CHEMISTRY OF 
 
 repairing, day by day, and minute by minute. 
 Hence it is that the estimations of the fuel and re- 
 pair material needed to keep the living animal body 
 in good working and thinking condition are, in the 
 present state of our knowledge, somewhat empir- 
 ical; but it is believed that, within certain wide 
 limits, useful calculations can be made by any one 
 willing to give a little time and thought to the sub- 
 ject. Our knowledge may be rapidly increased if 
 such study is made in many localities and under 
 varying circumstances. 
 
 The adult animal lives, repairs waste, and does 
 work; while the young animal does all these and 
 more — it grows. For growth and work something 
 else is needed beside starch and fat. The muscles 
 are the instruments of motion, and they must grow 
 and be nourished, in order that they may have 
 power. The nourishment is carried to them by the 
 blood in which, as well as in muscular tissue, there 
 is found an element which we have not heretofore 
 considered, namely, nitrogen. It has been proved 
 that the wear and tear of the muscles and brain 
 causes the liberation of nitrogenous compounds, 
 which pass out of the system as such, and this loss 
 must be supplied by the use of some kind of food 
 which contains nitrogen. Starch and fat do not 
 contain this element; therefore they cannot furnish 
 it to the blood. 
 
COOKING AND CLEANING. 49 
 
 Nitrogenous food-stuffs comprise at least two {££gX 
 large groups, the Albumins or Proteids and the 
 Albuminoids. 
 
 Albumins. 
 
 The Albumins in some form are never absent 
 from animal and vegetable organisms. They are 
 more abundant in animal flesh and in the blood. 
 The typical food of this class is the white of egg, 
 which is nearly pure albumin. Other common arti- 
 cles of diet belonging to this group are the casein 
 of milk, the musculin of animal flesh, the gluten of 
 wheat, and the legumin of peas and beans. 
 
 Egg albumin is soluble in cold water, but coagu- 
 lates at about 160 degrees F. At this point it is 
 tender, jelly-like, and easily digested, while at a 
 higher temperature it becomes tough, hard and sol- 
 uble with difficulty. 
 
 The albumin of flesh is contained largely in the 
 blood ; therefore the juices of meat extracted in cold 
 water form an albuminous solution. If this be 
 heated to the right temperature the albumin is 
 coagulated and forms the "scum" which many a 
 cook skims off and throws away. In doing this 
 she wastes a large portion of the nutriment. She 
 should retain this nutrition in the meat by the quick 
 coagulation of the albumin of the exterior, which 
 will prevent further loss, or use the nutritive solu- 
 
50 
 
 THE CHEMISTRY OF 
 
 Collagen. 
 
 Cooking of 
 
 Nitrogenous 
 
 Food-Stuffs. 
 
 tion in the form of soups or stews. "Clear soups" 
 have lost much of their nutritive value and, there- 
 fore, belong among the luxuries. 
 
 Albuminoids. 
 
 The animal skeleton — horns, bones, cartilage, 
 connective tissue, etc., contain nitrogenous com- 
 pounds which are converted by boiling into sub- 
 stances that form with water a jelly-like mass. 
 These are known as the gelatins. 
 
 The chief constituent of the connective tissues is 
 collagen. This is insoluble in cold water, but in hot 
 water becomes soluble and yields gelatine. Colla- 
 gen swells when heated and when treated with 
 dilute acids. Steak increases in bulk when placed 
 over the coals, and tough meat is rendered tender 
 by soaking in vinegar. Freshly killed meat is tough, 
 for the collagen is dry and hard. In time it becomes 
 softened by the acid secretions brought about 
 through bacterial action, and the meat becomes 
 tender and easily masticated. Tannic acid has the 
 opposite effect upon collagen, hardening and 
 shrinking it. This effect is taken advantage of in 
 tanning, and is the disadvantage of boiled tea as 
 a beverage. 
 
 Cooking should render nitrogenous food more 
 soluble because here, as in every case, digestibility 
 means solubility. Therefore, when the white of 
 
COOKING AND CLEANING. 61 
 
 egg (albumin), the curd of milk (casein), or the glu- 
 ten of wheat are hardened by heat, a much longer 
 time is required to effect solution. 
 
 As previously stated, egg albumin is tender and 
 jelly-like when heated from 160 degrees to 180 de- 
 grees. This fact should never be forgotten in the 
 cooking of eggs. Raw eggs are easily digested 
 and are rich in nutrition; when heated just enough 
 to coagulate the albumin or "the white," their di- 
 gestibility is not materially lessened; but when 
 boiled the albumin is rendered more difficultly 
 soluble. 
 
 To secure the greatest digestibility in combina- 
 tion with palatibility, they may be put into boiling 
 water, placed where the temperature can be kept 
 below 1 80 degrees, and left from ten to fifteen min- 
 utes, or even longer, as the albumin will not harden 
 and the yolk will become mealy. 
 
 To fry eggs the fat must reach a temperature — 
 300 degrees or over — far above that at which the 
 albumin of the egg becomes tough, hard, and well- 
 nigh insoluble. 
 
 The oyster, though not rich in nutrition, is read- Oysters, 
 ily digested when raw or slightly warmed. When 
 fried in a batter, it is so protected by the water in 
 the dough that the heat does not rise high enough 
 to render insoluble the albuminous morsel within. 
 Frying in crumbs (in which there is always 30 to 40 
 
52 THE CHEMISTRY OF 
 
 per cent water, even though the bread be dry) is 
 another though less efficient method of protection 
 for the albumin. Corn meal, often used as a coat- 
 ing, contains 10 to 12 per cent of water. 
 Gluten - Experiments on the digestibility of gluten have 
 
 proved that a high temperature largely decreases 
 its solubility. Subjected to artificial digestion for 
 the same length of time, nearly two and one half 
 times as much nitrogen was dissolved from the raw 
 gluten as from that which had been baked.* 
 
 When gluten is combined with starch, as in the 
 cereals, the difficulties of correct cooking are many, 
 for the heat which increases the digestibility of the 
 starch decreases that of the gluten. 
 Casein. The same principle applies to casein — the albu- 
 
 minous constituent of milk. There seems to be no 
 doubt that boiling decreases its solubility, and, con- 
 sequently, its digestibility for persons of delicate 
 digestive power. 
 
 The cooking of beans and all leguminous vege- 
 tables should soften the cellulose and break up 
 the compact grains of starch. Vegetables should 
 never be cooked in hard water, for the legumin of 
 the vegetable forms an insoluble compound with 
 the lime or magnesia of the water. 
 
 In the case of flesh the cooking should soften 
 
 *The Effect of Heat upon the Digestibility of Gluten, by Ellen H. Richards. 
 A. M., S. B., and Elizabeth Mason, A. B. Technology Quarterly, Vol. vii., 63 
 
 Legumin. 
 
COOKim AND CLEANING. 63 
 
 and loosen the connective tissue, so that the little 
 bundles of fibre which contain the nutriment may 
 fall apart easily when brought in contact with the 
 teeth. Any process which toughens and hardens 
 the meat should be avoided. 
 
 Whenever it is desired to retain the juices within 
 the meat or fish, it should be placed in boiling water 
 that the albumin of the surface may be hardened 
 and so prevent the escape of the albumin of the 
 interior. The temperature should then be low- 
 ered and kept between 160 and 180 degrees 
 during the time needed for the complete break- 
 ing down of the connective tissues. When 
 the nutriment is to be used in broths, stews 
 or soups, the meat should be placed in cold 
 water, heated very slowly and the temperature 
 not allowed to rise above 180 degrees until the 
 extraction is complete. To dissolve the softened 
 collagen, a temperature of 212 degrees is necessary 
 for a short time. 
 
 The object of all cooking is to make the food- object of 
 stuffs more palatable or more digestible or both 
 combined. 
 
 In general, the starchy foods are rendered more 
 digestible by cooking; the albuminous and fatty 
 foods less digestible. 
 
 The appetite of civilized man craves and custom 
 encourages the putting together of raw materials 
 
 Cooking. 
 
54 THE CHEMISTRY OF 
 
 of such diverse chemical composition that the 
 processes of cooking are also made complex. 
 
 Bread — the staff of life — requires a high degree 
 of heat to kill the plant-life, and long baking to 
 prepare the starch for solution; while, by the same 
 process, the gluten is made less soluble. 
 
 Fats, alone, are easily digested, but in the ordi- 
 nary method of frying, they not only become de- 
 composed themselves, and, therefore, injurious; 
 but they also prevent the necessary action of heat, 
 or of the digestive ferments upon the starchy ma- 
 terials with which the fats are mixed. 
 
 Pastry. Pastry owes its harmful character to this inter- 
 
 ference of fat with the proper solution of the starch. 
 Good pastry requires the intimate mixture of flour 
 with solid fat. The starch granules of the flour 
 must absorb water, swell, and burst before they can 
 be dissolved. The fat does not furnish enough 
 water to accomplish this, and it so coats the starch 
 granules as to prevent the sufficient absorption of 
 water in mixing, or from the saliva during mas- 
 tication. This coating of fat is not removed till 
 late in the process of digestion. The same effect is 
 produced by the combining of flour and fat in 
 made gravies. 
 
 Effect of The effect of cooking upon the solubility of the 
 
 three important food-principals may be broadly 
 stated thus : — 
 
 Cooking. 
 
COOKING AND CLEANING. 65 
 
 Starchy foods are made more soluble by long 
 cooking at moderate temperatures or by heat 
 high enough to dextrinize a portion of the starch, 
 as in the brown crust of bread. 
 
 Nitrogenous foods. The animal and vegetable 
 albumins are made less soluble by heat; the animal 
 albuminoids more soluble. 
 
 Fats are readily absorbed in their natural condi- 
 tion, but are decomposed at very high temperatures 
 and their products become irritants. 
 
T 
 
 CHAPTER V. 
 
 The Art of Cooking. 
 
 Flavors and Condiments. 
 
 HE science as well as the art of cooking lies in 
 the production of a subtle something which 
 gives zest to the food and which, though infinites- 
 imal in quantity, is of priceless value. It is the 
 savory potage, the mint, anise and cummin, the 
 tasteful morsel, the appetizing odor, which is, 
 rightly, the pride of the cook's heart. 
 Flavors. The most general term for this class of stimu- 
 
 lating substances is, perhaps, flavor — the gout of 
 the French, the Genuss-Mittel (enjoyment-giver) of 
 the Germans. 
 
 The development of this quality in food — taste, 
 savor, relish, flavor or what not, which makes "the 
 mouth water," depends, in every case, upon chem- 
 ical changes more subtle than any others known 
 to us. The change in the coffee berry by roasting 
 is a familiar illustration. The heat of the fire causes 
 the breaking up of a substance existing in the berry 
 and the production of several new ones. If the 
 heat is not sufficient, the right odor will not be 
 
COOKING AND CLEANING. 57 
 
 given ; if it is too great, the aroma will be dissipated 
 into the air or the compound will be destroyed. 
 
 This is an excellent illustration of the narrow Nature of 
 
 i-i 1- • 1 Flavors. 
 
 margin along which success lies. It is also chem- 
 ically typical of the largest number of flavors, 
 which seem to be of the nature of oils, set free by 
 the breaking up of the complex substances of which 
 they form a part. Nature has prepared these essen- 
 tial oils by the heat of the sun. They give the taste 
 to green vegetables ; while in fruits they are present 
 with certain acids, and both together cause the 
 pleasure-giving and therapeutic effects for which 
 fruit is noted. 
 
 It is probable that the flavors of roasted corn, 
 well-cooked oatmeal, toasted bread, also belong to 
 this class. Broiled steak and roasted turkey are 
 also illustrations, and with coffee show how easily 
 the mark is overstepped — a few seconds too long, 
 a very few degrees too hot, and the delicate morsel 
 becomes an acrid, irritating mass. 
 
 From this standpoint, cooking is an art as exact 
 as the pharmacist's, and the person exercising it 
 should receive as careful preparation; for these 
 flavors, which are so highly prized, are. many of 
 them the drugs and poisons of the apothecary and 
 are to be used with as much care. This is an addi- 
 tional reason for producing them by legitimate 
 means from the food itself, and not by adding the 
 
58 
 
 THE CHEMISTRY OF 
 
 Chemistry of 
 Flavors. 
 
 Condiments 
 and their 
 Effect. 
 
 crude materials in quantities relatively enormous to 
 those of the food substances. 
 
 The chemistry of cooking is therefore largely the 
 chemistry of flavor-production — the application of 
 heat to the food material in such a way as to bring 
 about the right changes and only these. 
 
 The flavors produced by cooking, correctly done, 
 will be delicate and unobtrusive. Usually, except 
 for broiled meats, a low heat applied for a long 
 time, with the use of closed cooking vessels, de- 
 velops the best flavors ; while quick cooking, which 
 necessitates a high temperature, robs the fine prod- 
 ucts of nature's laboratory of their choicest ele- 
 ments. Present American cookery, especially, sins 
 in this respect. Either the food is insipid from lack 
 of flavor or crudely seasoned at the last moment. 
 
 The secret of the success of our grandmothers' 
 cooking lay not solely in the brick oven — in the 
 low, steady heat it furnished — but in the care, 
 thought, and infinite pains they put into the prep- 
 aration of their simple foods. Compared with 
 these, the "one-minute" cereals, the "lightning" 
 pudding mixtures of the present are insipid, or 
 tasteless. Experience with the Aladdin Oven is an 
 education in flavor production. 
 
 Another source of stimulating flavor is found in 
 the addition of various substances called Condi- 
 ments. These consist of materials, of whatever 
 
COOKING AND CLEANING. 59 
 
 nature, added to the food compounds, to give them 
 a relish. Their use is legitimate; their abuse, harm- 
 ful. The effect of flavors is due to the stimulation 
 of the nerves of taste and smell. Condiments should 
 be used in a way to cause a like stimulation of the 
 nerves. If they are added to food materials before 
 or during the cooking process, a small quantity 
 imparts a flavor to the entire mixture. If added to 
 the cooked food, a larger quantity is used and the 
 effect lasts, not only while the food is in contact 
 with the nerves of the mouth, but also throughout 
 the digestive tract, causing an irritation of the 
 mucous membranes themselves. The tissues be- 
 come weakened, and, in time, lose the power of 
 normal action. 
 
 Cayenne pepper directjy applied to the food, 
 although sometimes a help, is oftener the cause in 
 dyspepsia. Highly seasoned food tends to weaken 
 the digestion in the end, by calling for more secre- 
 tion than is needed and so tiring out, as it were, 
 the glands. It is like the too frequent and violent 
 application of the whip to a willing steed — by and 
 by he learns to disregard it. Just enough to accom- 
 plish the purpose is nature's economy. 
 
 This economy is quick to recognize and be satis- 
 fied with a food which is easily digested without im- 
 pairing the functional powers of the digestive 
 fluids. A child seldom shows a desire for condi- 
 
60 
 
 THE CHEMISTRY OF 
 
 ments unless these have been first unwisely added 
 by adults. Flavors are largely odors, or odors and 
 tastes combined, and act upon the nervous system 
 in a natural way. Condiments, in many cases, are 
 powerful, stimulating drugs, exciting the inner lin- 
 ings of the stomach to an increased and abnormal 
 activity. Medicinally they may act as tonics. The 
 skill of the cook consists in steering between the 
 two digestion possibilities — hinder and help. 
 
 Some relish-giving substances, as meat extracts, 
 the caffeine of coffee, theine of tea, theo-bromine of 
 cocoa, and alcohol of wines go directly into the 
 blood and here act upon the nervous system. They 
 quicken the circulation and, therefore, stimulate to 
 increased activity. The cup of coffee thus drives 
 out the feeling of lassitude from wearied nerves and 
 muscles. Wine should never be treated as an arti- 
 cle of diet, but as a Gennss-Mittcl. 
 
 The secret of the cooking of vegetables is the 
 judicious production of flavor. In this the 
 French cook excels. She adds a little meat juice to 
 the cooked vegetables, thus obtaining the desired 
 flavor with the cheaper nutritious food. This wise 
 use of meats for flavor, while the actual food value 
 is made up from the vegetable kingdom, is an im- 
 portant item in public kitchens, institutions, or 
 wherever expense must be closely calculated. 
 
 In the study of economy, flavor-creation is of the 
 
COOKING AND CLEANING. 61 
 
 utmost importance. In foods, as everywhere, 
 science and art must supplement the purse, making 
 the few and cheaper materials necessary for nutri- 
 tion into a variety of savory dishes. Without the 
 appetizing flavor, many a combination of food ma- 
 terials is utterly worthless, for this alone stimu- 
 lates the desire or appetite, the absence of which 
 may prevent digestion. Food which pleases the 
 palate, unless this has been abnormally educated, 
 is usually wholesome, and judgment based on 
 flavor is normally a sound one. 
 
 - Starch may be cooked according to the most ap- Conditions 
 proved methods; but, if there is no saliva, the starch 
 is without food value. The piece of meat may be 
 done to a turn; but, if there is no gastric juice in 
 the stomach, it will not be dissolved, and hence is 
 useless. A homely illustration will best serve 
 our turn, — a cow may retain her milk by 
 force of will. It is well known how much 
 a contented mind has to do with her readi- 
 ness to give milk and the quantity of 
 milk she will yield. The various glands of the 
 human body seem to have a like action. The dry 
 mouth fails to moisten the food, and the stimulating 
 flavor is lost. On the other hand the mouth 
 "waters," and food is soon digested. The cow may 
 be utterly foolish and whimsical in her ideas — so 
 may persons. There may not be the least reason 
 
62 
 
 THE CHEMISTRY OF 
 
 Serving 
 
 Discretion in 
 Cooking. 
 
 Bacterial 
 Action Pro- 
 duces 
 Flavors. 
 
 Cooking an 
 Art. 
 
 why a person should turn away from a given food, 
 but if he does ? He suffers for his whims. 
 
 Hence the cook's art is most important, for its 
 results must often overcome adverse mental con- 
 ditions by nerve-stimulating flavors. The art 
 of serving, though out of place here, should be at- 
 tentively studied with the effect on the appetite 
 especially in view. This is of the utmost im- 
 portance in connection with hospital cooking. 
 
 Specific flavors, though agreeable in themselves, 
 should be used with discretion. In Norway, the 
 salmon is designedly cooked so as not to retain 
 much of its characteristic savor, for this is too de- 
 cided a flavor for an article of daily diet. In soups 
 and stews a "bouquet" of flavors is better than the 
 prominence of any one, although certain favorite 
 dishes may have a constant flavor. 
 
 Nature has produced many flavors and guarded 
 well the secret of their production; but science is 
 fast discovering their sources, as bacterial life and 
 action are better understood. Now, the "June 
 flavor" of butter may be produced in December, 
 by inoculating milk with the right "butter 
 bacillus." 
 
 Cooking has thus become an art worthy the at- 
 tention of intelligent and learned women. The 
 laws of chemical action are founded upon the laws 
 of definite proportions, and whatever is added more 
 
COOKING AND CLEANING. 63 
 
 than enough, is in the way. The head of every 
 household should study the condition of her fam- 
 ily, and tempt them with dainty dishes, if that is 
 what they need. Let her see to it that no burst of 
 ill temper, no sullen disposition, no intemperance 
 of any kind be caused by her ignorance or her dis- 
 regard of the chemical laws governing the reactions 
 of the food she furnishes. 
 
 When this science and this art takes its place be- 
 side the other sciences and other arts, one crying 
 need of the world will be satisfied. 
 
 We have now considered the three classes of 
 food in one or more of which all staple articles of 
 diet may be placed — the carbohydrates (starch and 
 sugar), the fats and the nitrogenous material. Some 
 general principles of diet, indicated by science, re- 
 main to be discussed. 
 
 Diet. 
 
 All preparation of food-stuffs necessary to make ^estion °' 
 them into suitable food for man comes under the Saliva, 
 head of what has been called "external digestion." 
 The processes of internal digestion begin in the 
 mouth. Here the saliva not only lubricates the 
 finely divided portions of the food materials, but, 
 in the case of starch, begins the process of chang- 
 ing the insoluble starch into a soluble sugar. This 
 process is renewed in the small intestine. The fats 
 
64 
 
 THE CHEMISTRY OF 
 
 Mastication. 
 
 Pepsin and 
 Acid of 
 Stomach. 
 
 Decomposi- 
 tion Products. 
 
 are emulsified in the small intestine, and, with the 
 soluble carbohydrates, are here largely absorbed. 
 
 All the chemical changes which the nitrogenous 
 food stuffs undergo are not well understood. Such 
 food should be finely comminuted in the mouth, 
 because, as before stated, chemical action is rapid 
 in proportion to the fineness of division; but it is 
 in the stomach that the first chemical change 
 occurs. 
 
 The chief agents of this change are pepsin 
 and related substances, aided by the acid of the 
 gastric juice; these together render the nitrogenous 
 substance soluble and capable of passing through 
 the membranes. Neither seems able to do this 
 alone, for if the acid is neutralized, action ceases; 
 and if pepsin is absent, digestion does not take 
 place. 
 
 Decompositions of a very complex kind occur, 
 peptones are formed which are soluble compounds, 
 and the nitrogen finally passes out of the system as 
 urea, being separated by the kidneys, as carbon di- 
 oxide is separated by the lungs. 
 
 One of the most obvious questions is: Which is 
 best for human food — starch or fat, beans and peas, 
 or flesh? As to starch or fat, the question has been 
 answered by experience, and science has only tried 
 to explain the reason. The colder the climate, the 
 more fat the people eat. The tropical nations live 
 
COOKING AND CLEANING. 
 
 65 
 
 chiefly on starchy foods, as rice. From previous 
 statements it will be seen that this is right in princi- 
 ple. Fat yields more heat than rice; therefore the 
 inference is plain that in the cold of winter fat is 
 appropriate food, while in the heat of summer rice 
 or some other starchy food should be substituted. 
 
 The diet of summer should also contain much 
 fruit. Increased perspiration makes necessary an 
 increased supply of water. This may be furnished 
 largely by fruits, and with the water certain acids 
 are taken which act as correctives in the digestive 
 processes. 
 
 No evident rule can be seen in the case of the 
 albuminous foods. At most, the class can be di- 
 vided into three groups. The first includes the ma- 
 terial of vegetable origin, as peas, lentils, and the 
 gluten of wheat. The second comprises the white 
 of Qgg and the curd of milk — material of animal 
 origin. The third takes in all the animal flesh used 
 by mankind as food. 
 
 Considering the question from a purely chemical 
 standpoint, without regarding the moral or social 
 aspects of the case, two views stand out clearly: 
 ist. If the stored-up vegetable matter has required 
 the force derived from the sun to prepare it, the 
 tearing apart and giving back to the air and earth 
 the elements of which it was built up will yield the 
 same amount of force to whatever tears it down; 
 
 Seasonable 
 Diet. 
 
 Economy of 
 a Mixed 
 Diet. 
 
66 THE CHEMISTRY OE 
 
 but a certain amount of energy must be used up in 
 this destruction. 2d. If the animal, having accom- 
 plished the decomposition of the vegetable and ap- 
 propriated the material, is killed, and the prepared 
 nitrogenous food in the form of muscle is eaten by 
 man, then little force is necessary to render the 
 food assimilable ; it is only to be dissolved in order 
 that it may enter into the circulation. The force- 
 producing power is not lost; it is only transferred 
 to another animal body. Hence the ox or the 
 sheep can do a part of man's work for him in pre- 
 paring the vegetable food for use, and man may 
 thus accomplish more than he otherwise could. 
 This digestion of material outside of the body is 
 carried still further, by man, in the manufacture of 
 partially digested foods, — "malted," "peptonized," 
 "pre-digested," etc. Exclusive use of these is 
 fraught with danger, for the organs of digestion 
 lose power, if that which they have, however 
 little, be long unused. 
 Food of Nearly all, if not all, young animals live on food 
 
 Animals. Q f animal origin. The young of the human race 
 
 live on milk; but it has been found by experience 
 that milk is not the best food for the adult to live 
 upon to the exclusion of all else. It is not con- 
 ducive to quickness of thought or general bodily 
 activity. 
 Sbfe°Food g " Experience leads to the conclusion that mankind 
 
COOKING AND CLEANING. 67 
 
 needs some vegetable food. Two facts sustain this 
 inference. The digestive organs of the herbivorous 
 animals form fifteen to twenty per cent of 
 the whole weight of the body. Those of 
 the carnivorous animals form five to six 
 per cent, those of the human race, about 
 eight per cent. The length of the canal 
 through which the food passes varies in about the 
 same ratio in the three classes. A mixed diet seems 
 to be indicated as desirable by every test which has 
 been applied; but the proportions in which the 
 vegetable and animal "food are to be mingled, as 
 well as the relative quantities of carbonaceous and 
 nitrogenous material which will give the best effi- 
 ciency to the human machine are not so easily 
 determined. 
 
 Nature seems to have made provision for the ex- Wa tcr and 
 cess of heat resulting from the oxidation of too 
 much starch or fat, by the ready means of evapora- 
 tion of water from the surface; this loss of water 
 being supplied by drinking a fresh supply, which 
 goes, without change, into the circulation. The 
 greater the heat, the greater the evaporation ; hence 
 the importance of water as an article of diet, espe- 
 cially for children, must not be overlooked. For 
 an active person, the supply has been estimated at 
 three quarts per day. Water is the heat regulator 
 of the animal body. An article entitled "Water 
 
 Air as Food. 
 
68 THE CHEMISTRY OF 
 
 and Air as Food,"* by one of the authors of this 
 book, treats this subject more thoroughly. 
 
 Dangers of While dangerous disease seldom results from 
 
 eating an excess of starch or fat, because the por- 
 tion not wanted is rejected as if it were so much 
 sand, many of the most complicated disorders do 
 result from an excess of nitrogenous diet. 
 
 The readiness with which such substances under- 
 go putrefaction, and the many noxious products to 
 which such changes give rise, should lead us to be 
 more careful as to the quantity of this food. 
 
 From experiments made by the best investiga- 
 tors, it seems probable that only one third of the 
 estimated daily supply of food is available for ki- 
 netic force ; that is, that only about one third of the 
 total energy contained in the daily food can be util- 
 ized in digging trenches, carrying bricks, climbing 
 mountains, designing bridges, or writing poems 
 and essays. The other two thirds is used up in the 
 internal work of the body — the action of the heart, 
 lungs, and the production of the large amount of 
 heat necessary to life. 
 
 Dietaries. It has been estimated that a growing person 
 
 needs about one part of nitrogenous food to four of 
 starch and fat; a grown person, one part nitro- 
 genous to five or six of starch and fat. If this is 
 
 ♦Rumford Kitchen Leaflet, No. 6, American Kitchen Magazine, Vol. IV., 
 357. 
 
COOKING AND CLEANING. 69 
 
 true, then we may make out a life ration, or that 
 amount of food which is necessary to keep the 
 human machine in existence. 
 
 For this climate, and for the habits of our people, 
 we have estimated this life ration as approximately: 
 
 Proteid. Fat. Carbohydrates. Calories. 
 
 75 grams. 40 grams. 325 grams. 2,000. 
 
 The amount of energy given out in the form of 
 work cannot exceed the amount of energy taken in 
 in the form of food; so this life ration is increased 
 to make a maximum and minimum for a work 
 ration. For professional or literary persons the 
 following may be considered a sufficient maximum 
 and minimum: 
 
 Proteid. 
 
 Fat. 
 
 Carbohydrates. 
 
 Calories. 
 
 i«5 grams. 
 
 125 grams. 
 
 450 grams. 
 
 3.5°o- 
 
 no grams. 
 
 90 grams. 
 
 420 grams. 
 
 3,000. 
 
 For hard manual labor about one-third is to be 
 added to the above rations. An examination of the 
 actual dietaries of some of the very poor who eat 
 just enough to live, without doing any work, 
 shows that in twelve cases the average diet was : 
 
 Proteid. Fat. Carbohydrates. Calories. 
 
 31 grams. 81 grams. 272 grams. 2,257. 
 
 For further information on these points see the 
 list of works at the end of this book. 
 
 The first office of the food, then, is to keep the offices ot 
 human body in a high condition of health; the 
 second, to enable it to exert force in doing the work 
 
 Food. 
 
70 COOKING AND CLEANING. 
 
 of the world; and a third, the value of which it is 
 hardly possible to estimate, is to furnish an im- 
 portant factor in the restoration of the body to nor- 
 mal condition, when health is lost. In sickness, 
 far more than in health, a knowledge of the right 
 proportions of the essential food substances, and of 
 the absolute quantity or food value given, is im- 
 portant. How many a life has been lost because of 
 a lack of this knowledge the world will never know. 
 
PART II 
 
 THE CHEMISTRY OF CLEANING. 
 
 CHAPTER I. 
 Dust. 
 
 MANY a housewife looks upon dust as her in- 
 veterate enemy against whom incessant war- 
 fare brings only visible defeat. Between the battles, 
 let us study the enemy — the composition of his 
 forces, his tactics, his ammunition, in order that 
 we may find a vantage ground from which to direct 
 our assault, or from which we may determine 
 whether it is really an enemy which we are fighting. 
 
 The Century dictionary defines dust as "Earth, Definition of 
 or other matter in fine dry particles so attenuated 
 that they can be raised and carried by the wind." 
 This suggests that dust is no modern product of 
 the universe. Indeed, its ancestry is hidden in 
 those ages of mystery before man was. Who can 
 say that it does not reach to that eternity which can 
 be designated only by "In the beginning?" 
 
72 THE CHEMISTRY OP 
 
 Necessity of Tyndall proved by delicate experiments that 
 
 when all dust was removed from the track of a 
 beam of light, there was darkness. So before the 
 command "Let there be light," the dust-condition 
 of light must have been present. Balloonists find 
 that the higher they ascend the deeper the color of 
 the sky. When at a distance of some miles, the 
 sky is nearly black, there is so little dust to scatter 
 the rays of light. If the stellar spaces are dustless, 
 they must be black and, therefore, colorless. The 
 moisture of the air collects about the dust-particles 
 giving us clouds and, with them, all the glories of 
 sunrise and sunset. Fogs, too, are considered to 
 be masses of "water-dust," and ships far out at sea 
 have had their sails colored by this dust, while sail- 
 ing through banks of fog. Thinking, now, of the 
 above definition, it may be said that the earth, in 
 its final analysis, must be dust deposited during 
 past ages; that to dust is due the light necessary 
 to life, and that without it certain phenomena of 
 nature — clouds, color, fog, perhaps, even rain and 
 snow could not exist. 
 
 It behooves us, then, as inhabitants of this dust- 
 formed and dust-beautified earth to speak well of 
 our habitation. We have found no enemy yet. 
 The enemy must be lurking in the "other matter." 
 This the dictionary says is in powdered form, car- 
 ried by the air, and, therefore, at times existent in 
 
COOKING AND CLEANING. 
 
 73 
 
 it, as has been seen. A March wind gives sensible 
 proof of this, but what about the quiet air, whether 
 out of doors or in our houses? 
 
 An old writer has said: "The sun discovers 
 atonies, though they be invisible by candle-light, 
 and makes them dance naked in his beams." Those 
 sensible particles with these "atonies," which be- 
 come visible in the track of a beam of light when- 
 ever it enters a darkened room, make up the dust 
 whose character is to be studied. 
 
 Astronomers find meteoric dust in the atmos- 
 phere. When this falls on the snow and ice fields 
 of the Arctic regions, it is readily recognized. The 
 eruption of Krakatoa proved that volcanic dust' is 
 disseminated world-wide. Dust contains mineral 
 matter, also, from the wear and tear of nature's 
 forces upon the rocks, bits of dead matter given off 
 by animal and vegetable organisms, minute fibres 
 from clothing, the pollen of plants, the dry and pul- 
 verized excrement of animals. These constituents 
 are easily detected — are they all? 
 
 Let a mixture of flour and water stand out-of- 
 doors, leave a piece of bread or bit of cheese on 
 the pantry shelves for a week. The mixture fer- 
 ments, the bread and cheese mold. Formerly, these 
 changes were attributed to the "access of air" — i. e., 
 to the action upon the substances, of the oxygen of 
 the air; later experiments have proved that if the 
 
 Visible and 
 
 Invisible 
 
 Dust. 
 
 Composition 
 of Dust 
 
 Dust Plants. 
 
74 THE' CHEMISTRY OF 
 
 air be previously passed through a cotton-wool 
 filter it will cause no change in the mixture. The 
 oxygen is not filtered out, so it cannot be the cause 
 of the fermentation. Now, such phenomena of 
 fermentation are known to be caused by minute 
 vegetable organisms which exist everywhere in the 
 air and settle from it when it becomes dry and still. 
 They are molds, yeasts and bacteria. All are mi- 
 croscopic and many sub-microscopic.^ They are 
 found wherever the atmosphere extends — some 
 inches below the surface of the ground and 
 some miles above it, although on the tops of the 
 highest mountains and, perhaps, far out at sea, 
 the air is practically free from earthly dust, 
 and therefore nearly free from these forms. The 
 volcanic dust of the upper air does not appear to 
 contain them. They are all spoken of as "germs," 
 because they are capable of developing into grow- 
 ing forms. All are plants belonging to the fungi; 
 in their manner of life essentially like the plants 
 we cherish, requiring food, growing, and repro- 
 ducing their kind. They require moisture in order 
 to grow or multiply; but, like the seeds of higher 
 plants, can take on a condition calculated to resist 
 hard times and endure these for long periods ; then 
 when moisture is furnished, they immediately 
 spring into growth. In the bacteria these spores 
 are a resting stage, not primarily reproduc- 
 
COOKING AND CLEANING. 
 
 75 
 
 tive; while, in molds, they bring forth an active, 
 growing plant. 
 
 The common puff-ball (Lycoperdon), the "smoke" 
 ball of the country child, well illustrates both vege- 
 tative and spore stages. This belongs to the fungi, 
 is closely related to the molds, and consists of a 
 spherical outer wall of two layers, enclosing tissues 
 which form numerous chambers with membraneous 
 partitions. Within these chambers are formed the 
 reproductive cells or spores. When ripe, the mass 
 becomes dry, the outer layer of the wall scales off, 
 the inner layer splits open, allowing the minute dry 
 spores to escape as a "cloud of dust." These are 
 readily carried by the wind until caught on some 
 moist spot favorable for their growth. They are 
 found on dry, sandy soils, showing that very little 
 moisture is needed; but when this is found, the 
 spore swells, germinates, and grows into a new 
 vegetative ball, which completes the cycle. 
 
 Wheat grains taken from the wrappings of mum- 
 mies are said to have sprouted when given moist- 
 ure and warmth. Whether this be true or not, there 
 can be no doubt that the vitality of some seeds and 
 spores is wonderfully enduring. 
 
 The spores of some of the bacteria may be boiled 
 and many may be frozen — still life will remain. 
 
 Aristotle declared that "all dry bodies become 
 damp and all damp bodies which are dried engen- 
 
 Spores. 
 
 Vital Endur- 
 ance. 
 
 Dangerous 
 Dust, 
 
76 THE CHEMISTRY OF 
 
 der animal life." He believed these dust germs to 
 be animalcules spontaneously generated wherever 
 the conditions were favorable. How could he, with- 
 out the microscope, explain in any other way the 
 sudden appearance of such myriads of living forms? 
 
 Now, it is recognized that the air everywhere 
 contains the spores of molds and bacteria, and it 
 is this dust, carried in the air, which falls in our 
 houses. This is our enemy. 
 
 A simple housemaid once said that the sun 
 brought in the dust "atomes" through the window, 
 and the careful, old, New England housewife 
 thought the same. So, she shut up the best room, 
 making it dark and, therefore, damp. Unwittingly, 
 she furnished to them the most favorable conditions 
 of growth, in which they might increase at the rate 
 of many thousands in twenty-four hours. 
 
 "Let there be light" must be the ever-repeated 
 command, if we would take the first outpost of the 
 enemy. 
 
 We live in an invisible atmosphere of dust, we 
 are constantly adding to this atmosphere by the 
 processes of our own growth and waste, and, finally, 
 we shall go the way of all the earth, contributing 
 our bodies to the making of more dust. Thus dust 
 has a decided two-fold aspect of friendliness and 
 enmity. We have no wish to guard ourselves 
 against friends; so, for the present purposes, the 
 
COOKING AND CLEANING. 77 
 
 inimical action of dust, as affecting the life and 
 health of man, alone need challenge our attention. 
 The mineral dust, animal waste, or vegetable 
 debris, however irritating to our membranes, or 
 destructive of our clothing, are enemies of minor 
 importance, compared with these myriads of living 
 germs, which we feel not, hear not, see not, and 
 know not until they have done their work. 
 
 From a sanitary point of view, the most im- Bacteria, 
 portant of the three living ingredients of dust is 
 that called bacteria. They are the most numerous, 
 the most widely distributed, and perhaps the small- 
 est of all living things. Their natural home is the 
 soil. Here they are held by moisture, and by the 
 gelatinous character caused, in large part, by their 
 own vital action. When the surface of the ground 
 becomes dry, they are carried from it, by the wind, 
 into the air. Rain and snow wash them down; 
 running streams take them from the soil; so that, at 
 all times, the natural waters contain immense num- 
 bers of them. They are heavier than the air and 
 settle from it in an hour or two, when it is dry and 
 still. They are now quietly resting on this page 
 which you are reading. They are on the floor, the 
 tops of doors and windows, the picture frames, in 
 every bit of ''fluff" which so adroitly eludes the 
 broom — in fact, everywhere where dust can lodge. 
 
 The second ingredient, in point of numbers, is Molds, 
 
78 THE CHEMISTRY OF 
 
 the molds. They, too, are present in the air, both 
 outside and inside of our houses; but being much 
 lighter than the bacteria, they do not settle so 
 quickly, and are much more readily carried into the 
 air again, by a very slight breeze. 
 
 Yeasts. The third, or wild yeasts, are not usually trouble- 
 
 some in the air or in the dust of the house, where 
 ordinary cleanliness rules. 
 
 "Dirt." To the bacteriologist, then, everything is dirty 
 
 unless the conditions for germ-growth have been 
 removed, and the germs, once present, killed. 
 All of this dirt cannot be said to be "matter in the 
 wrong place," only when it is the wrong kind of 
 matter in some particular place. The bacteria are 
 Nature's scavengers. Every tree that falls in the 
 forest — animal or vegetable matter of all kinds is 
 immediately attacked by these ever-present, invisi- 
 ble agents. By their life-processes, absorbing, se- 
 creting, growing and reproducing, they silently 
 convert such matter into various harmless sub- 
 stances. They are faithful laborers, earning an 
 honest living, taking their wages as they go. Their 
 number and omnipresence show the great amount 
 of work there must be for them to do. 
 
 Then why should we enter the lists against such 
 opponents? Because this germ-community is like 
 any other typical community. 
 
 The majority of the individuals are law-abiding, 
 
COOKING AND CLEANING. 79 
 
 respectable citizens; yet in some dark corner a thief 
 may hide, or a cut-throat steal in unawares. If 
 this happens, property may be destroyed and life 
 itself endangered. 
 
 All of these forms destroy our property; 
 but a certain few of the bacteria cause disease 
 and death. In a very real sense, so soon as an or- 
 ganism begins to live it begins to die ; but these are 
 natural processes and do not attract attention so 
 long as the balance between the two is preserved. 
 When the vital force is lessened, by whatever cause, 
 disease eventually shows itself. Methods for the 
 cure of disease are as old as disease itself; but 
 methods for the prevention of disease are of late 
 birth. Here and there along the past, some minds, 
 wiser than their age, have seen the possibilities of 
 such prevention; but superstition and ignorance 
 have long delayed the fruition of their hopes. 
 
 "An ounce of prevention is worth a pound of Prevention of 
 cure," though oft repeated has borne scanty fruit 
 in) daily living. When the cause of smallpox, 
 tuberculosis, diphtheria, typhoid fever, and other 
 infectious diseases is known to be a living plant, 
 which cannot live without food, it seems, at first 
 sight, a simple matter to starve it out of existence. 
 This has proved to be no simple nor easy task; so 
 much the more is each person bound by the law 
 of self-love and the greater law, 'Thou shalt love 
 
 Disease. 
 
80 THE CHEMISTRY OF 
 
 thy neighbor as thyself," to do his part toward 
 driving these diseases from the world. 
 
 Any one of these dust-germs is harmless so long 
 as it cannot grow. Prevent their growth in the 
 human body, and the diseased condition cannot 
 occur. 
 
 Prevention, then, is the watchword of modern 
 sanitary science. 
 
 It may be asked: How do the germs cause dis- 
 ease ? 
 
 Why do they not always cause disease? 
 
 Numerous answers have been given during the 
 short time the germ theory of infectious diseases 
 has been studied. If we follow the history of this 
 study, we may find, at least, a partial answer. 
 Action of A person is "attacked" by smallpox, diphtheria, 
 
 lockjaw, typhoid fever, or some kindred disease. 
 Common speech recognizes in the use of the word 
 "attacked" that an enemy from outside has begun, 
 by force, a violent onset upon the person. This 
 enemy — a particular bacterium or other germ, has 
 entered the body in some way. There may have 
 been contact with another person ill with the same 
 disease. The germ may have entered through food 
 on which it was resting, by water, or by dust as 
 it touched the exposed flesh, where the skin was 
 broken by a scratch or cut. It found in the blood 
 or flesh the moisture and warmth necessary for its 
 
 Bacteria. 
 
COOKING AND CLEANING. 81 
 
 growth, and, probably, a supply of food at once de- 
 sirable and bountiful. It began to feed, to grow, 
 and to multiply rapidly, until the little one became 
 a million. At this stage the patient knew he was 
 ill. It was thought, at first, that the mere presence 
 in the body of such enormous numbers caused the 
 disease. 
 
 Bacteria like the same kinds of food which we Food of 
 
 Bacteria. 
 
 like. Though they can and will live on starvation 
 rations, they prefer a more luxurious diet. This 
 fact led to the idea that they supplied their larder 
 by stealing from the food supply of the invaded 
 body; so that, while the uninvited and unwelcome 
 guest dined luxuriously, the host sickened of starva- 
 tion. This answer is now rejected. 
 
 The food of the bacteria is not only similar in 
 kind to our own food, but it must also undergo like 
 processes of solution and absorption. 
 
 Solution is brought about by the excretion of 
 certain substances, similar in character and in ac- 
 tion to the ferments secreted in the animal mouth, 
 stomach and intestines. These excretions reduce 
 the food materials to liquids, which are then ab- 
 sorbed. 
 
 The pathogenic or disease-producing germs are 
 found to throw out during their processes of as- 
 similation and growth, various substances which 
 are poisons to the animal body, as are aconite and 
 
S2 
 
 THE CHEMISTRY OF 
 
 digitalis. These are absorbed and carried by the blood 
 throughout the entire system. These poisons are 
 called toxines. It is now believed that it is these 
 bacterial products, the toxines or poisons, which 
 are the immediate cause of the diseased condition. 
 
 inoculation. Inoculation of some of the lower animals with 
 
 the poisoned blood of a diseased person, in which 
 blood no germ itself was present, has repeatedly 
 produced the identical disease. It is far easier to 
 keep such manufacturers out of the body than to 
 "regulate" their manufactures after an entrance has 
 been gained. 
 
 These faint glimpses into the "Philosophy of 
 Cleanness" lead to another question, namely: How 
 shall we keep clean? 
 
 The first requisite for cleanness is light — direct 
 sunlight if possible. It not only reveals the visible 
 dirt, but allies itself with us as an active agent 
 towards the destruction of the invisible elements of 
 uncleanness. That which costs little or nothing is 
 seldom appreciated; so this all-abundant, freely- 
 
 Suniight. given light is often shut out through man's greed 
 
 or through mistaken economy. The country dwell- 
 er surrounds his house with evergreens or shade 
 trees, the city dweller is surrounded by high brick 
 walls. Blinds, shades, or thick draperies shut out 
 still more, and prevent the beneficent sunlight from 
 acting its role of germ-prevention and germ-de- 
 
 Requisites 
 for Clean- 
 
COOKING AND CLEANING. 83 
 
 struction. Bright-colored carpets and pale-faced 
 children are the opposite results which follow. 
 "Sunshine is the enemy of disease, which thrives in 
 darkness and shadow." Consumption and scrofu- 
 lous diseases are well-nigh inevitable, when blinds 
 are tightly closed and trees surround the house, 
 causing darkness, and, thereby, inviting dampness. 
 As far as possible let the exterior of the house be 
 bathed in sunlight. Then let it enter every nook and 
 cranny. It will dry up the moisture, without which 
 the tiny disease germs or other plants cannot grow; 
 it will find and rout them by its chemical action. 
 Its necessity and power in moral cleanness, who 
 can measure? 
 
 More plentiful than sunlight is air. We cannot Pure Air. 
 shut it out entirely as we can light; but there is 
 dirty air just as truly as dirty clothes and dirty 
 water. The second requisite for cleanness, then, 
 is pure air. 
 
 Primitive conditions of human life required no primitive 
 thought of the air supply, for man lived in the open ; Life. mons c 
 but civilization brings the need of attention and 
 care for details; improvements in some directions 
 are balanced by disadvantages in others; luxuries 
 crowd out necessities, and man pays the penalty 
 for his disregard of Nature's laws. Sunlight, pure 
 air and pure water are our common birthright, 
 which we often bargain away for so-called com- 
 forts. 
 
84 THE CHEMISTRY OP 
 
 Sunlight is purity itself. Man cannot contam- 
 inate it, but the air about him is what man makes it. 
 Naturally, air is the great "disinfectant, antiseptic 
 and purifier, and not to be compared for a moment 
 with any of artificial contrivance," but under man's 
 abuse it may become a death-dealing breath. 
 
 Charlemagne said: "Right action is better than 
 knowledge ; but to act right one must know right." 
 Nature's supply of pure air is sufficient for all, but 
 to have it always in its pure state requires knowl- 
 edge and constant, intelligent action. 
 Products oi The gaseous products of the combustion carried 
 
 Combustion. . , . ,,.,., .. - 
 
 on within our bodies; like products from our arti- 
 ficial sources of heat and light — burning coal, gas 
 and oil ; waste matters of life and manufactures car- 
 ried into the air through fermentation and putre- 
 faction — all these, with the innumerable sources of 
 dust we have already found, load the air with im- 
 purities. Some are quickly recognized by sight, 
 smell or taste; but many, and these the more dan- 
 gerous, are unrecognizable by any sense. They 
 show their actions in our weakened, diseased and 
 useless bodies. Dr. James Johnson says: "All 
 the deaths resulting from fevers are but a drop in 
 the ocean, when compared with the numbers who 
 perish from bad air." 
 Air Pollution. The per cent of pollution in the country is much 
 
 smaller than in the city, where a crowded popula- 
 
COOKING AND CLEANING. 85 
 
 tion and extensive manufactories are constantly 
 pouring forth impure matters, but by rapidly mov- 
 ing currents, even this large per cent is soon diluted 
 and carried away. Would that the air in country 
 houses, during both winter and summer, might 
 show an equally small per cent! 
 
 Air is a real substance. It can be weighed. It AiraSub- 
 will expand, and may be compressed like other 
 gases. It requires considerable force to move it, 
 and this force varies with the temperature. When 
 a bottle is full of air, no more can be poured in. 
 Our houses are full of air all the time. No more 
 can come in till some has gone out. In breathing, 
 we use up a little, but it is immediately replaced 
 by expired air, which is impure. * Were there no 
 exits for this air, no pure air could enter, and we 
 should soon die of slow suffocation. The better 
 built the house the quicker the suffocation, unless 
 special provision be made for a current of fresh air 
 to push out the bad. Fortunately no house is air 
 tight. Air will come in round doors and windows, 
 but this is neither sufficient to drive out the bad 
 nor to dilute it beyond harm. Therefore the air of 
 all rooms must be often and completely changed, 
 either by special systems of ventilation, or by in- 
 telligent action in the opening of doors and win- 
 dows. 
 
 Sunlight and pure air are the silent but powerful Qeanness 
 
86 COOKING AND CLEANING. 
 
 allies of the housewife in her daily struggle toward 
 the ideal cleanness, i. e., sanitary cleanness, the 
 cleanness of health. Without these allies she may 
 spend her strength for naught, for the plant-life of 
 the quiet, -dust-laden air will grow and multiply far 
 beyond her powers of destruction. These dust- 
 plants or micro-organisms grow rapidly in warm 
 places where there is moisture. Collections of 
 dust in cracks and corners, lodged in depressions 
 of the surface, as in seams and carvings, or held 
 by rough, absorbent materials as fabrics, at all 
 times furnish the seed. All organic materials 
 furnish soil or food. Therefore the half-dried 
 milk-can, the partly cleaned dripping-pan, the 
 dampened clothes in the laundry basket, the wet 
 dishcloth and damp towel will soon become a 
 flourishing dust-garden. 
 
 A dust-garden suggests growth ; growth of 
 dust means fermentation with its consequent 
 chemical changes. Fermentation is a process of 
 decomposition which may end in putrefaction. 
 This means economic waste. 
 
 Civilized man requires so many articles for his 
 convenience and comfort that the problem of 
 cleanness has grown to be most complex. 
 
 But dry dust is not the only enemy. The 
 mixture of dust with greasy, sugary or smoky 
 deposits makes the struggle twofold. 
 
CHAPTER II. 
 Dust Mixtures. 
 
 Grease and Dust. 
 
 THE various processes of housework give rise 
 to many volatile substances. These, the vapors 
 of water or fat, if not carried out of the house in 
 their vaporous state will cool and settle upon all 
 exposed surfaces, whether walls, furniture or fab- 
 rics. This thin film entangles and holds the dust, 
 clouding and soiling, with a layer more or less visi- 
 ble, everything within the house. Imperfect ven- 
 tilation allows additional deposits from fires and 
 lights — the smoky products of incomplete com- 
 bustion. 
 
 Thorough ventilation is, then, a preventive meas- 
 ure, which ensures a larger removal not only of the 
 volatile matters, but also of the dust, with its possi- 
 ble disease germs. 
 
 Dust, alone, may be removed from most sur- 
 faces with a damp or even with a dry cloth, or from 
 fabrics by vigorous shaking or brushing; but, 
 usually, the greasy or sugary deposits must first be 
 broken up and, thus, the dust set free. This must be 
 accomplished without harm to the material upon 
 
 Sources of 
 Dirt. 
 
 Removal of 
 Dust. 
 
88 
 
 THE CHEMISTRY OF 
 
 Processes of 
 Cleaning. 
 
 Grease-Oils. 
 
 Alkali Metals. 
 
 which the unclean deposit rests. Here is a broad 
 field for the application of chemical knowledge. 
 
 Cleaning, then, involves two processes: First, 
 the greasy film must be broken up, that the en- 
 tangled dust may be set free. Second, the dust 
 must be removed by mechanical means. Disinfec- 
 tion sometimes precedes these processes, in or- 
 der that the dangerous dust-plants may be killed 
 before removal. 
 
 To understand the methods of dust removal, it 
 is necessary to consider the chemical character of 
 the grease and, also, that of the materials effectual 
 in acting upon it. 
 
 Grease or fats, called oils when liquid at ordinary 
 temperature, are chemical compounds made of dif- 
 ferent elements, but all containing an ingredient 
 known to the chemist as a fatty acid. 
 
 The chemist finds in nature certain elements 
 which, with the fatty acids, form compounds en- 
 tirely different in character from either of the orig- 
 inal ingredients. These elements are called the 
 alkali metals and the neutral compounds formed by 
 theif union with the acid of the fat are familiarly 
 known to the chemist as salts. 
 
 The chemical group of "alkali metals" comprises 
 six substances : Ammonium, Caesium, Lithium, Po- 
 tassium, Rubidium and Sodium. Two of the six — 
 Caesium and Rubidium — were discovered by means 
 
COOKING AND CLEANING. 89 
 
 of the spectroscope, not many years ago, in the min- 
 eral waters of Durckheim, and, probably, the total 
 amount for sale of all the salts of these two metals 
 could be carried in one's pocket. A third alkali 
 metal — Lithium — occurs in several minerals, and 
 its salts are of frequent use in the laboratory, but it 
 is not sufficiently abundant to be of commercial 
 importance. As regards the three remaining alkali 
 metals, the hydrate of Ammonium (NH 4 )OH, is 
 known as "Volatile Alkali," the hydrates of Po- 
 tassium, KOH, and Sodium, NaOH, as "Caustic 
 Alkalies." With these three alkalies and their 
 compounds, and these alone, are we concerned 
 in housekeeping. The volatile alkali, Ammonia, is 
 now prepared in quantity and price such that every 
 housekeeper may become acquainted with its use. 
 It does not often occur in soaps, but it is valuable 
 for use in all cleansing operations — the kitchen, 
 the laundry, the bath, the washing of woolens, and 
 in other cases where its property of evaporation, 
 without leaving any residue to attack the fabric or 
 to attract anything from the air, is invaluable. The 
 most extensive household use of the alkalies is in 
 the laundry, under which head they will be more 
 specifically described. 
 
 Some .of the fatty acids combine readily with s <> a P s - 
 alkalies to form compounds which we call soaps. 
 Others in contact with the alkalies form emulsions, 
 
90 
 
 THE CHEMISTRY OF 
 
 The Problem 
 of Cleaning. 
 
 Cleaning of 
 
 Different 
 
 Materials. 
 
 " Finish " of 
 Woods. 
 
 so-called, in which the fatty globules are suspended, 
 forming an opaque liquid. These emulsions are 
 capable of being indefinitely diluted with clear 
 water, and, by this means, the fatty globules are all 
 carried away. Most of the fats are soluble in ben- 
 zine, ether, chloroform, naphtha or alcohol. 
 
 If the housekeeper's problem were the simple 
 one of removing the grease alone, she would solve 
 it by the free use of one of these solvents or by 
 some of the strong alkalies. This is what the 
 painter does when he is called to repaint or to re- 
 finish; but the housewife wishes to preserve the 
 finish or the fabric while she removes the dirt. She 
 must, then, choose those materials which will dis- 
 solve or unite with the grease without injury to the 
 articles cleaned. 
 
 The greasy film which entangles the unclean and 
 possibly dangerous dust-germs and dust-particles 
 is deposited on materials of widely different char- 
 acter. These materials may be roughly divided 
 into two classes : One, where, on account of some 
 artificial preparation, the uncleanness does not 
 penetrate the material but remains upon the sur- 
 face, as on wood, metal, minerals, leather and some 
 wall paper; the other, where the grease and dust 
 settle among the fibres, as in fabrics. 
 
 In the interior of the house, woods are seldom 
 used in their natural state. The surface is covered 
 
COOKING AND CLEANING. 
 
 91 
 
 with two or more coatings of different substances 
 which add to the wood durability or beauty. The 
 finish used is governed by the character of the 
 wood, the position and the purpose which it serves. 
 The cleaning processes should affect the final coat 
 of finish alone. 
 
 Soft woods are finished with paint, stain, oil, 
 shellac, varnish, or with two or more of these com- 
 bined; hard woods with any of these and, in addi- 
 tion, encaustics of wax, or wax with turpentine or 
 oil. 
 
 All these surfaces, except those finished with 
 wax, may be cleaned with a weak solution of soap 
 or ammonia, but the continued use of any such 
 alkali will impair and finally remove the polish. 
 Waxed surfaces are turned dark by water. Fin- 
 ished surfaces should never be scoured nor cleaned 
 with strong alkalies, like sal-soda or potash soaps* 
 To avoid the disastrous effects of these alkalies the 
 solvents of grease may be used or slight friction 
 applied. Turpentine dissolves paint. 
 
 Kerosene and turpentine are efficient solvents for 
 grease and a few drops of these on a soft cloth may 
 be used to clean all polished surfaces. The latter 
 cleans the more perfectly and evaporates readily; 
 the former is cheaper, safer, because its vapor is not 
 so inflammable as that of turpentine, and it polishes 
 a little while it cleans; but it evaporates so slowly 
 
 * If the finish has become very greasy, smoky or worn, it may be 
 economy to use as strong an alkali as sal-soda. The washing and rinsing 
 should be as rapid as possible. Refinishing may be necessary for clean 
 conditions. 
 
 Varnish, Oil, 
 Wax. 
 
 Solvents of 
 Grease. 
 
92 THE CHEMISTRY OF 
 
 that the surface must be rubbed dry each time, or 
 dust will be collected and retained. The harder the 
 rubbing, the higher the polish.* 
 
 Outside of the kitchen, the woodwork of the 
 house seldom needs scrubbing. The greasy layer 
 is readily dissolved by weak alkaline solutions, by 
 kerosene or turpentine, while the imbedded dust is 
 wiped away by the cloth. Polished surfaces keep 
 clean longest. Strong alkalies will eat through the 
 polish by dissolving the oil with which the best 
 paints, stains or polishes are usually mixed. If the 
 finish be removed or broken by deep scratches, the 
 wood itself absorbs the grease and dust, and the 
 stain may have to be scraped out. 
 
 Woodwork, whether in floors, standing finish or 
 furniture, from which the dust is carefully wiped 
 every day, will not need frequent cleaning. A 
 few drops of kerosene or some clear oil rubbed or 
 with a second cloth will keep the polish bright and 
 will protect the wood. 
 
 Certain preparations of non-drying oils are now 
 in the market, which, when applied to floors, serve 
 to hold the dust and prevent its spreading through 
 the room and settling upon the furnishings. They 
 are useful in school-rooms, stores, etc., where the 
 floor cannot be often cleaned. The dust and dirt 
 stick in the oil and, in time, the whole must be 
 cleaned off and a new coating applied. 
 
 * Continued use of kerosene on white paint tends to turn it yellow. 
 
COOKING AND CLEANING. 93 
 
 Many housewives fear to touch the piano, how- a ciean 
 ever clouded or milky the surface may become. 
 The manufacturers say that pianos should be 
 washed with soap and water. Use tepid water with 
 a good quality of hard soap and soft woolen or cot- 
 ton-flannel cloths. Wash a small part at a time, 
 rinse quickly with clear water that the soap may 
 not remain long, and wipe dry immediately. Do 
 all quickly. A well-oiled cloth wiped over the sur- 
 face and hard rubbing with the hand or with cham- 
 ois will improve the appearance. If there are deep 
 scratches which go through the polish to the wood, 
 first, cover them with oil and allow it to soak in, 
 or dark lines will appear where the alkali and 
 w r ater touched the natural wood. 
 
 Painted surfaces, especially if white, may be paint, 
 cleaned with whiting, applied with a moistened 
 woolen cloth or soft sponge. Never let the 
 cloth be wet enough for the water to run or 
 stand in drops on the surface. Wipe "with 
 the grain" of the wood, rinse in clear 
 water with a second soft cloth and wipe 
 dry with a third. All washed surfaces should 
 be wiped dry, for moisture and warmth furnish the 
 favorable conditions of growth for all dust-germs, 
 whether bacteria or molds. Cheese cloth may be 
 used for all polished surfaces, for it does not 
 scratch and washes easily. 
 
94 THE CHEMISTRY OF 
 
 Walls painted with oil paints may be cleaned 
 with weak ammonia water or whiting in the same 
 manner as woodwork; but if they are tinted with 
 water colors, no cleaning can be done to them, for 
 both liquids and friction will loosen the coloring 
 matter. 
 
 Waii-Paper. Papered walls should be wiped down with cheese 
 
 cloth, with the rough side of cotton flannel, or some 
 other soft cloth. This will effectually remove all 
 free dust. Make a bag the width of the broom or 
 brush used. Run in drawing strings. Draw the 
 bag over the broom, and tie closely round the han- 
 dle, just above the broom-corn. Wipe the walls 
 down with a light stroke and the paper will not be 
 injured. An occasional thorough cleansing will be 
 needed to remove the greasy and smoky deposits. 
 The use of bread dough or crumb is not recom- 
 mended, for organic matter may be left upon the 
 wall. A large piece of aerated rubber — the 
 "sponge" rubber used by artists for erasing their 
 drawings — may be used effectually, and will leave 
 no harmful deposit. "Cartridge" paper may be 
 scoured with fine emery or pumice powder, for the 
 color goes through. Other papers have only a thin 
 layer of color. 
 
 Varnished and waxed papers are now made 
 which may be wiped with a damp cloth. 
 
 Leather. Leather may be wiped with a damp cloth or be 
 
COOKING AND CLEANING. 95 
 
 kept fresh by the use of a little kerosene. An occa- 
 sional dressing of some good oil, well rubbed in, 
 will keep it soft and glossy. 
 
 Marble may be scoured with fine sand-soap or Marble, 
 powdered pumice, or covered with a paste of whit- 
 ing, borax or pipe-clay, mixed with turpentine, 
 ammonia, alcohol or soft soap. This should be left 
 to dry. When brushed or washed off, the marble 
 will be found clean. Polish with coarse flannel or 
 a piece of an old felt hat. Marble is carbonate of 
 lime, and any acid, even fruit juices, will unite 
 with the lime, driving out the carbon dioxide, 
 which shows itself in effervescence, if the quantity 
 of acid be sufficient. Acids, then, should not touch 
 marble, if it is desired to keep the polish intact. 
 An encaustic of wax and turpentine is sometimes 
 applied to marbles to give them a smooth, shining 
 surface. These must not be scoured.* 
 
 Pastes of whiting, pipe-clay, starch or whitewash 
 may be put over ornaments of alabaster, plaster and 
 the like. The paste absorbs the grease and, by rea- 
 son of its adhesive character, removes the grime 
 and dust. 
 
 Most metals may be washed without harm in a Metals, 
 hot alkaline solution or wiped with a little kerosene. 
 Stoves and iron sinks may be scoured with the 
 coarser materials like ashes, emery or pumice; but 
 copper, polished steel, or the soft metals, tin, silver, 
 and zinc require a fine powder that they may not 
 
 *New marbles bave a very high polish which is easily scratched. 
 These should be washed, not scoured. 
 
96 THE CHEMISTRY OF 
 
 be scratched or worn away too rapidly. MetaJ 
 bathtubs may be kept clean and bright with whiting 
 and ammonia, if rinsed with boiling hot water and 
 wiped dry with soft flannel or chamois. 
 
 Porcelain. Porcelain or soapstone may be washed like metal 
 
 or scoured with any fine material. 
 
 Glass. Glass of windows, pictures and mirrors may be 
 
 cleaned in many ways. It may be covered with a 
 whiting paste mixed with water, ammonia or alco- 
 hol. Let the paste remain till dry, when it may be 
 rubbed off with a sponge, woolen cloth or paper. 
 Polish the glass by hard rubbing with news- 
 papers or chamois. Alcohol evaporates more 
 quickly than water and therefore hastens the 
 process; but it is expensive and should not touch 
 the sashes, as it might turn the varnish. Very good 
 results are obtained with a tablespoonful of kero- 
 sene to a quart of warm water. In winter, when 
 water would freeze, windows may be wiped with 
 clear kerosene and rubbed dry. Kerosene does not 
 remove fly specks readily, but will take off grease 
 and dust. Fly specks may be dissolved in alcohol 
 or strong alkali, or be scraped off with some 
 dull, hard edge, as a cent, nickel or the back of 
 a knife. 
 
 Success in washing glass depends more upon 
 manipulation than materials. It is largely a matter 
 of patience and polishing. The outer surface of 
 
COOKING AND CLEANING. M 
 
 windows often becomes roughened by the dissolv- 
 ing action of rain water, or milky and opaque by 
 action between the sun, rain and the potash or soda 
 in the glass. Ordinary cleaning will not make such 
 windows clear and bright. The opaqueness may 
 sometimes be removed by rubbing with vinegar 
 or dilute muriatic acid. Polish with whiting. 
 
 Household fabrics, whether carpets, draperies Fabrics, 
 or clothing, collect large quantities of dust, which 
 no amount of brushing or shaking will entirely dis- 
 lodge. They also absorb vapors which con- 
 dense and hold the dust-germs still more firmly 
 among the fibres. Here the fastness of color and 
 strength of fibre must be considered, for a certain 
 amount of soaking will be necessary in order that 
 the cleansing material may penetrate through the 
 fabric. In general, all fabrics should be washed 
 often in an alkaline solution. If the colors will not 
 stand the application of water, they may be cleansed 
 in naphtha or rubbed with absorbents. The chem- 
 istry of dyeing has made such progress during the 
 last ten years that fast colors are more frequently 
 found, even in the cheaper grades of fabrics, than 
 could be possible before this time. It is now more 
 a question of weak fibre than of fleeting color. 
 Heavy fabrics may therefore be allowed to soak 
 for some time in many waters, or portions of naph- 
 tha, being rinsed carefully up and down without 
 
THE CHEMISTRY OF 
 
 Inflammable 
 Materials. 
 
 Prevention of 
 Dirt. 
 
 rubbing. All draperies or woolen materials should 
 be carefully beaten and brushed before any other 
 cleaning is attempted. Wool fabrics hold much of 
 the dirt upon their hook-like projections, and these 
 become knotted and twisted by hard rubbing. If 
 the fabric be too weak to be lifted up and down in 
 the liquid bath, it may be laid on a sheet, over a 
 folded blanket, and sponged on both sides with the 
 soap or ammonia solution or with the naphtha. If 
 the colors are changed a little by the alkalies, rinse 
 the fabrics in vinegar or dilute acetic acid ; if affect- 
 ed by acids, rinse in ammonia water. 
 
 In the use of naphtha, benzine, turpentine, etc., 
 great caution is necessary. The vapor of all these 
 substances is extremely inflammable. They should 
 never be used where there is any fire or light pres- 
 ent, nor likely to be for several hours. A bottle 
 containing one of them should never be left un- 
 corked. Whenever possible, use them out-of- 
 doors. 
 
 With both dust and grease, prevention is easier 
 than removal. If the oily vapors of cooking and 
 the volatile products of combustion be removed 
 from the kitchen and cellar, and not allowed to dis- 
 sipate themselves throughout the house, the greasy 
 or smoky deposits will be prevented and the re- 
 moval of the dust-particles and dust-plants will be- 
 come a more mechanical process. Such vapors 
 
COOKING AND CLEANING. 99 
 
 should be removed by special ventilators or by win- 
 dows open at the top, before they become con- 
 densed and thus deposited upon everything in the 
 house. Let in pure air, drive out the impure; fill 
 the house with sunshine that it may be dry, and the 
 problem of cleanness is largely solved. 
 
 Economy of time, labor and materials results 
 in removing dust and dust mixtures, frequently. 
 
 "One keep-clean is worth a dozen make- 
 clean" is as true now as it was generations ago. 
 The sooner a wrong condition can be removed 
 the easier will be its removal; less time will be 
 required; and much less harm done to the 
 articles cleaned. 
 
 The organic matter which is present in most 
 dirt tends to harden or to change in other ways 
 and, therefore, to become removable with diffi- 
 culty. It may undergo chemical changes which 
 make it indelible. 
 
 In fabrics the fibres may even be destroyed. 
 
T 
 
 CHAPTER III. 
 Stains, Spots, Tarnish. 
 
 l HESE three classes include the particular de- 
 posits resulting from accident, careless- 
 ness, or the action of special agents, as the 
 tarnish on metals. They are numerous in char- 
 acter, occur on all kinds of materials and their re- 
 moval is a problem which perplexes all women 
 and which requires considerable knowledge and 
 much patience to solve. A few suggestions may 
 help some one who has not yet found the best 
 way for herself. 
 
 Grcascspots. Grease seems to be the most common cause of 
 
 such spots. Small articles that can be laundered 
 regularly with soap and water, give little trouble. 
 These will be discussed in the following chapter. 
 
 Absorbents of Spots of grease on carpets, heavy materials, or 
 
 colored fabrics of any kind which cannot be con- 
 veniently laundered, may be treated with absorb- 
 ents. Heat will assist in the process by melting 
 the grease. Fresh grease spots on such fabrics 
 may often be removed most quickly by placing 
 over the spot a piece of clean white blotting paper 
 or butcher's wrapping paper, and pressing the spot 
 with a warm iron. It is well to have absorbent 
 
COOKING AND CLEANING. 101 
 
 paper or old cloth under the spot as well. Heat 
 sometimes changes certain blues, greens and reds, 
 so it is well to work cautiously and hold the iron 
 a little above the goods till the effect can be noted. 
 
 French chalk, — a variety of talc, or magnesia, 
 may be scraped upon the spot and allowed to re- 
 main for some time, or applied in fresh portions, 
 repeatedly. If water can be used, chalk, fuller's 
 earth or magnesia may be made into a paste with 
 it or with benzine and this spread over the spot. 
 When dry, brush the powder off with a soft brush. 
 
 For a fresh spot on fabrics of delicate texture or 
 color, when blotting paper is not at hand, a 
 visiting or other card may be split and 
 the rough inner surface rubbed gently over the 
 spot. Slight heat under the spot may hasten the 
 absorption. Powdered soapstone, pumice, whit- 
 ing, buckwheat flour, bran or any kind of coarse 
 meal are good absorbents to use on carpets or up- 
 holstery. They should be applied as soon as the 
 grease is spilled. Old spots will require a solvent 
 and fresh ones may be treated in the same way. 
 
 Grease, as has been said, may be removed in Solvents of 
 three ways, by forming a solution, an emulsion, 
 or a true soap. Wherever hot water and soap can 
 be applied, the process is one of simple emulsion, 
 and continued applications should remove both 
 the grease and the entangled dust; but strong 
 
 Grease. 
 
102 THE CHEMISTRY OF 
 
 soaps ruin some colors and textures. Ammonia 
 or borax may replace the soap, still the water may 
 affect the fabric, so the solvents of grease are safer 
 for use. Chloroform, ether, alcohol, turpentine, 
 benzine and naphtha, all dissolve grease. In their 
 commercial state some of these often contain im- 
 purities which leave a residue, forming a dark ring, 
 which is as objectionable as the original grease. 
 Turpentine is useful for coarser fabrics, while 
 chloroform, benzine and naphtha are best for silks 
 and woolens. Ether or chloroform can usually 
 be applied to all silks, however delicate. 
 Whenever these solvents are used, there 
 should be placed under the spot some absorb- 
 ent material, like a thick pad of cloth, blot- 
 ting paper or a layer of chalk to take up the 
 excess of liquid. 
 
 Then rub the spot from the outside toward 
 the center to prevent the spreading of the 
 liquid, to thin the edges, and, thus, to ensure 
 rapid and complete evaporation. The cleansing 
 liquid should not be left to dry of itself. 
 The cloth should be rubbed dry, but very 
 carefully, for the rubbing may remove the 
 nap from woolen goods and, therefore, change 
 the color or appearance. Apply the solvent 
 with a cloth as nearly like the fabric to be 
 cleaned, in color and texture, as possible, 
 
COOKING AND CLEANING. 
 
 103 
 
 or, in general, use a piece of sateen, which does 
 not grow linty. On thick goods a stiff brush, 
 and on thin goods a soft one, will reach into the 
 meshes. This should be struck against the cloth 
 more than rubbed across it. It is well to apply 
 all cleansing liquids and all rubbing on the wrong 
 side of the fabric. None of these solvents can be 
 used near a flame. 
 
 The troublesome "dust spot" has usually a neg- 
 lected grease spot for its foundation. After the 
 grease is dissolved, the dust must be cleaned out 
 by thorough rinsing with fresh liquid or by brush- 
 ing after the spot is dry. 
 
 Our grandmothers found ox-gall an efficient 
 cleanser both for the general and special deposits. 
 It is as effectual now as then and is especially good 
 for carpets or heavy cloths. It may be used clear 
 for spots, or in solution for general cleansing and 
 brightening of colors. Its continued use for car- 
 pets does not fade the colors as ammonia or salt 
 and water is apt to do. 
 
 Cold or warm grease on finished wood can be 
 wiped off easily with a woolen cloth moistened 
 in soapsuds or with a few drops of turpentine. 
 Soap should never be rubbed on the cloth except, 
 possibly, for very bad spots round the kitchen 
 stove or table. Solutions of washing soda, potash, 
 or the friction, that may be used safely on linfin- 
 
 " Dust 
 spots." 
 
 Ox-gall. 
 
 Grease-spots 
 on Wood. 
 
104 THE CHEMISTRY OF 
 
 ished woods, will take out the grease but will also 
 destroy the polish. 
 
 Hot grease usually destroys the polish and 
 sinks into the wood. It then needs to be treated 
 like grease on unfinished wood or scraped out 
 with fine steel wool or wire fibre, sandpaper or 
 emery paper. The color and polish must then be 
 renewed. When hot grease is spilled on wood or 
 stone, if absorbents are not at hand, dash cold 
 water on it immediately. This will solidify the 
 grease and prevent its sinking deeply into the ma- 
 terial. 
 
 Grease or oil stains on painted walls, wall-paper 
 or leather, may be covered with a paste of pipe- 
 clay, or French chalk and water. Let the paste 
 dry and after some hours carefully brush off the 
 powder. Sometimes a piece of blotting paper laid 
 over the spot and a warm iron held against this, 
 will draw out the grease. These pastes of absorb- 
 ent materials are good for spots on marbles. They 
 may then be mixed with turpentine or ammonia 
 or soft soap. 
 
 Paint is made of oil, lead or zinc oxide 
 arid pigment. Spots of paint, then, must be 
 treated with something which will take out the oil, 
 leaving the insoluble coloring matter to be 
 brushed off. When fresh, such spots may 
 be treated with turpentine, benzine or naph- 
 
COOKING AND CLEANING. 105 
 
 tha. For delicate colors or textures, chloroform 
 or naphtha is the safest. The turpentine, un- 
 less pure, may leave a resinous deposit. This 
 may be dissolved in chloroform or benzine, but 
 care should be exercised in the use of alcohol 
 for it dissolves some coloring matters. Old paint 
 spots often need to be softened by the application 
 of grease or oil; then the old and the new may be 
 removed together. Whenever practicable, let all 
 spots soak a little, that the necessity of hard rub- 
 bing may be lessened. 
 
 Paint on stone, bricks or marble, may be treated 
 with strong alkalies and scoured with pumice 
 stone or fine sand. 
 
 Varnish and pitch are treated with the same varnish and 
 
 . r Pitch. 
 
 solvents as paint — turpentine being the one in 
 general use, — when the article stained will not 
 bear strong alkalies. Pitch and tar usually need 
 to be covered first with grease or oil, to soften 
 them. 
 
 Wax spots made from candles should be re- Wax. 
 moved by scraping off as much as possible, then 
 treating the remainder with kerosene, benzine, 
 ether, naphtha, or with blotting paper and a warm 
 iron, as grease spots are treated. The soap and 
 water of ordinary washing will remove slight 
 spots. The spermaceti is often mixed with tallow 
 which makes a grease spot, and with coloring mat- 
 ters which may require alcohol, 
 
106 
 
 THE CHEMISTRY OF 
 
 Food Stains. 
 
 Wheel 
 G ease. 
 
 Spots made by food substances are greasy, sug- 
 ary or acid in their character, or a combination of 
 these. That which takes out the grease will gen- 
 erally remove the substance united with it, as the 
 blood in meat juices. The sugary deposits are us- 
 ually soluble in warm water. If the acids from 
 fresh fruits or fruit sauces affect the color of the 
 fabric, a little ammonia water may neutralize the 
 acid and bring back the color. Dilute alcohol 
 may sometimes be used as a solvent for colored 
 stains from fruit. Blood requires cold or tepid 
 water, never hot. After the red color is removed 
 soap and warm water may be used. 
 
 Blood stains on thick cloths may be absorbed 
 by repeated applications of moist starch. 
 
 Wheel-grease and lubricants of like nature are 
 mixtures of various oils and may contain soaps or 
 graphite. The ordinary solvents of the vegetable 
 or animal oils will remove these mixtures from 
 colored fabrics by dissolving the oil. The undis- 
 solved coloring matter will, for the most part, pass 
 through the fabric and may be collected on thick 
 cloth or absorbent paper, which should always be 
 placed underneath. From wash goods, it may be 
 removed, readily, by strong alkalies and water, es- 
 pecially if softened first by kerosene or the addition 
 of more grease, which increases the quantity of 
 soap made. Graphite is the most difficult of re- 
 moval. 
 
COOKING AND CLEANING. 107 
 
 Ink spots are perhaps the worst that can be en- ink stains, 
 countered, because of the great uncertainty of the 
 composition of the inks of the present day. When 
 the character of an enemy is known it is a compar- 
 atively simple matter to choose the weapons to be 
 used against him, but an unknown enemy must be 
 experimented upon, and conquest is uncertain. 
 Methods adapted to the household are difficult to 
 find, as the effective chemicals need to be applied 
 with considerable knowledge of proportions and 
 effects. Such chemicals are often poisons and, 
 in general, their use by unskilled hands is not to 
 be recommended. 
 
 Fresh ink will sometimes yield to clear cold 01 
 tepid water. Skimmed milk is safe and often ef- 
 fective. If the cloth is left in till the milk sours, 
 the result is at times more satisfactory. This has 
 proved effective on light colored dress goods 
 where strong acids might have affected the colored 
 printed patterns. Some articles may have a bit of 
 ice laid over the stain with blotting paper under 
 it to absorb the ink solution. Remove the satur- 
 ated portions quickly and continue the process till 
 the stain has nearly or quite disappeared. The last 
 slight stain may be taken out with soap and water. 
 Some colored dress goods will bear the applica- 
 tion of hot tartaric acid or of muriatic acid, a drop 
 at a time, as on white goods. 
 
108 THE CHEMISTRY OF ' 
 
 Ink on carpets, table covers, draperies or heavy, 
 dark cloths of any kind, may be treated immedi- 
 ately with absorbents to keep the ink from spread- 
 ing. Bits of torn blotting paper may be held at 
 the surface of the spot to draw away the ink on 
 their hairy fibres. Cotton-batting acts in the same 
 way. Meal, flour, starch, sawdust, baking soda 
 or other absorbents may be thrown upon the ink 
 and carefully brushed up when saturated. If much 
 is spilled, it may be dipped up with a spoon or 
 knife, adding a little water to replace that taken 
 up, until the whole is washed out. Then dry the 
 spot with blotting paper. The cut surface of a 
 lemon may be used, taking away the stained por- 
 tion as soon as blackened. Usually it requires 
 hard rubbing to remove the last of the stain. Car- 
 pets may be rubbed with a floor brush, while a 
 soft toothbrush may be used for more delicate ar- 
 ticles. With white goods a solution of bleaching 
 powder may be used, but there is always danger 
 of rotting the fibres unless rinsing in ammonia 
 water follow, in order that the strong acid of the 
 powder may be neutralized. 
 
 Fresh ink stains on polished woods may be 
 wiped off with clear water, and old stains of some 
 inks likewise yield to water alone. The black col- 
 oring matter of other inks may be wiped off with 
 the water, but a greenish stain may still remain 
 
COOKING AND CLEANING. 
 
 109 
 
 which requires turpentine. In general, turpentine 
 is the most effectual remover of ink from polished 
 woods. 
 
 The indelible inks formerly owed their perman- 
 ence to silver nitrate; now, many are made from 
 aniline solutions and are scarcely affected by any 
 chemicals. The silver nitrate inks, even after ex- 
 posure to light and the heat of the sun or of a hot 
 flat-iron, may be removed by bleaching liquor. 
 The chlorine replaces the nitric acid forming a 
 white silver chloride. This may be dissolved in 
 strong ammonia or a solution of sodium hyposul- 
 phite. Sodium hyposulphite, which may be 
 bought of the druggists, will usually remove the 
 silver inks without the use of bleaching fluid and is 
 not so harmful to the fibres. Some inks contain 
 carbon which is not affected by any chemicals. 
 
 The aniline inks, if treated with chemicals may 
 spread over the fabric and the last state be worse 
 than the first. Other chemicals are effective with 
 certain inks, but some are poisonous in themselves 
 or in their products, some injure the fabric, and 
 all require a knowledge of chemical reactions in 
 order to be safely handled. Dried ink stains on 
 silver, as the silver tops of inkstands may be 
 moistened with chloride of lime and rubbed hard. 
 
 Polished marble may be treated with turpen- 
 tine, "cooking soda" or strong alkalies, remerrh 
 
 Indelible 
 Inks. 
 
 Aniline Inks 
 
 Marble, 
 
110 THE CHEMISTRY OF 
 
 bering that acids should never touch marble if it 
 is desired to retain the polish. If the stain has 
 penetrated through the polish, a paste of the alkali 
 and turpentine may be left upon the spot for some 
 time and then washed off with clear water. 
 
 Porcelain. Sometimes the porcelain linings of hoppers 
 
 and bowls become discolored with yellowish- 
 brown stains from the large quantities of iron in 
 the water supply. These should be taken off with 
 muriatic acid. Rinse in clean water and, lastly, 
 with a solution of potash or soda to prevent any 
 injurious action of the acid on the waste pipes. 
 
 Alcohol. Alcohol dissolves shellac. Most of the interior 
 
 woodwork of the house, whether finish or furni- 
 ture, has been coated with shellac in the process 
 of polishing. If then, any liquid containing alco- 
 hol, as camphor, perfumes, or medicines, be spilled 
 upon such woodwork and allowed to remain, a 
 white spot will be made, or if rubbed while wet, 
 the dissolved shellac will be taken off and the bare 
 wood exposed. 
 
 Heat. Heat also turns varnish and shellac white. A 
 
 hot dish on the polished table leaves its mark. 
 These white spots should be rubbed with oil till the 
 color is restored. 
 
 If a little alcohol be brushed over the spot with 
 a feather, a little of the surrounding shellac is dis- 
 solved and spread over the stained spot. Hard 
 
COOKING AND CLEANING. 
 
 Ill 
 
 rubbing with kerosene will, usually, remove the 
 spot and renew the polish. If the shellac be re- 
 moved and the wood exposed the process of re- 
 newal must be the original one of coloring, shellac- 
 ing and polishing, until the necessary polish is ob- 
 tained. 
 
 Caustic alkalies, strong solutions of sal-soda, 
 potash and the like, will eat off the finish. Apply 
 sweet, olive, or other vegetable oils, in case of 
 such accidents. The continued use of oils or al- 
 kalies always darkens natural woods. 
 
 The special deposits on metals are caused by the 
 oxygen and moisture of the air, by the presence of 
 other gases in the house, or by acids or corroding 
 liquids. Such deposits come under the general 
 head of tarnish. 
 
 The metals, or their compounds, in common use 
 are silver, copper and brass, iron and steel, tin, 
 zinc and nickel. Aluminum is rapidly taking a 
 "prominent place in the manufacture of household 
 utensils. 
 
 There is little trouble with the general greasy 
 film or with the special deposits on articles in daily 
 use, if they are washed in hot water and soap, 
 rinsed well and wiped dry each time. Yet certain 
 articles of food act upon the metal of tableware 
 and cooking utensils, forming true chemical salts. 
 The salts of silver are usually dark colored and in- 
 
 A'.kalies. 
 
 Chemical 
 Compounds. 
 
 Tarnish on 
 Silver. 
 
112 THE CHEMISTRY OF 
 
 soluble in water or in any alkaline liquid which will 
 not also dissolve the silver. Whether found in the 
 products of combustion, in food, as eggs, in the 
 paper or cloth used for wrapping, in the rubber 
 band of a fruit jar, or the rubber elastic which may 
 be near the silver, sulphur forms with silver a gray- 
 ish black compound — a sulphide of silver. All the 
 silver sulphides are insoluble in water. Rub such 
 tarnished articles, before washing, with common 
 salt. By replacement, silver chloride, a white chem- 
 ical salt, is formed, which is soluble in ammonia. 
 If the article be not washed in ammonia it will soon 
 turn dark again. Most of these metallic com- 
 pounds formed on household utensils being insolu- 
 ble, friction must be resorted to. 
 silverware. The matron of fifty years ago took care of her 
 
 silver herself or closely superintended its clean- 
 ing, for the articles were either precious heirlooms 
 or the valued gifts of friends. The silver of which 
 they were made was hardened by a certain propor- 
 tion of copper and took a polish of great brilliancy 
 and permanence. The matron of to-day, who has 
 the same kind of silver or who takes the same care, 
 is the exception. Plated ware is found in most 
 households. The silver deposited from the battery 
 is only a thin coating of the pure soft metal — very 
 bright when new, but easily scratched, easily tar- 
 nished, and never again capable of taking a beauti- 
 
Powders 
 
 COOKING AND CLEANING. 113 
 
 ful polish. The utensils, being of comparatively 
 little value, are left to the table-girl to clean. She, 
 naturally, uses the material which will save her 
 labor. 
 
 In order to ascertain if there was any foundation silver 
 for the prevalent opinion that there was mercury or 
 some equally dangerous chemical in the silver pow- 
 ders commonly sold, samples were purchased in 
 Boston and vicinity, and in New York and vicinity. 
 
 Of the thirty-eight different kinds examined. 
 
 25 were dry powder. 
 10 " partly liquid. 
 3 " soaps. 
 
 Of the twenty-five powders, fifteen were chalk or 
 precipitated calcium carbonate, with a little color- 
 ing matter, usually rouge. 
 
 6 were diatomaceous earth. 
 2 " fine sand entirely. 
 2 " fine sand partly. 
 
 Mercury was found in none. No other injurious 
 chemical was found in any save the "electro-plating 
 battery in a bottle," which contained potassium 
 cyanide, KCN, a deadly poison; but it was labeled 
 poison, although the label also stated that "all salts 
 of silver are poison when taken internally." This 
 preparation does contain silver, and does deposit a 
 thin coating, but it is not a safe article for use. 
 
114 
 
 THE CHEMISTRY OF 
 
 Silver 
 Polishes. 
 
 Whiting. 
 
 Cleaning of 
 Silver in 
 Quantity. 
 
 Of the nine polishes, partly liquid, five contained 
 alcohol and ammonia for the liquid portion; four, 
 alcohol and sassafras extract. The solid portion, in 
 all cases, was chalk, with, in one case, the addition 
 of a little jeweler's rouge. 
 
 The caution to be observed in the use of these 
 preparations is in regard to the fineness of the ma- 
 terial. A few coarse grains will scratch the coat- 
 ing of soft silver. Precipitated chalk, CaC0 3 , or 
 well-washed diatomaceous earth, Si0 2 , seem to be 
 of the most uniform fineness. 
 
 We may learn a lesson in this, as well as in many 
 other things, from the old-fashioned housewife. 
 She bought a pound of whiting for twelve cents, 
 sifted it through fine cloth, or floated off the finer 
 portion, and obtained twelve ounces of the same 
 material, for three ounces of which the modern 
 matron pays twenty-five or fifty cents, according to 
 the name on the box. 
 
 The whiting may be made into a paste with am- 
 monia or alcohol, the article coated with this and 
 left till the liquid has evaporated. Then the pow- 
 der should be rubbed off with soft tissue paper or 
 soft unbleached cloth, and polished with chamois. 
 
 Sometimes it is desirable to clean a large quantity 
 of silverware at one time, but the labor of scouring 
 and polishing each piece is considerable. They 
 may all be placed carefully in a large kettle — a clean 
 
COOKING AND CLEANING. 
 
 115 
 
 wash-boiler is convenient for packing the large 
 pieces — and covered wi|th a strong solution of 
 washing-soda, potash or borax. Boil them in this 
 for an hour or less. Let them stand in the liquor 
 till it is cold; then polish each piece with a little 
 whiting and chamois. A good-sized piece of zinc 
 boiled with the silverware will help to clean away 
 any sulphides present, by replacing the silver in 
 them and forming a white compound. 
 
 Silver should never be rubbed with nor wrapped 
 in woolen, flannel or bleached cloth of any kind, 
 for sulphur is commonly used in bleaching proc- 
 esses; nor should rubber in any form be present 
 where silver is kept. The unused silver may be 
 wrapped in soft, blue-white or pink tissue paper, 
 prepared without sulphur, and packed in un- 
 bleached cotton flannel cases, each piece separately. 
 Silver jewelry, where strong soap or other alkali 
 is not sufficient for the cleaning process, may be 
 immersed in a paste of whiting and ammonia, and 
 when dry, brushed carefully with a soft brush. If 
 there be a doubt as to the purity of the silver, re- 
 place the ammonia by sweet oil or alcohol. The 
 ammonia and whiting are also good for gold. Jew- 
 elry cleaned with water may be dried in boxwood 
 sawdust. 
 
 Care is necessary in the use of ammonia in or on 
 "silver" topped articles, as vinaigrettes. These tops 
 
 Protection ol 
 Silverware. 
 
 Silver 
 Jewelry. 
 
 Copper and 
 Silver. 
 
116 
 
 THE CHEMISTRY OF 
 
 Brass, Copper. 
 
 Oxidation of 
 Metals. 
 
 are often made of copper with a thin layer of silver. 
 Whenever the ammonia remains upon the copper, 
 it dissolves it, forming poisonous copper salts. 
 
 Brass and copper must not be cleaned with am- 
 monia unless due care is taken that every spot be 
 rinsed and wiped perfectly dry. Nothing is better 
 for these metals than the rotten-stone and oil of old- 
 time practice. These may be mixed into a paste at 
 the time of cleaning or be kept on hand in quantity. 
 Most of the brass polishes sold in the market are 
 composed of these two materials, with a little alco- 
 hol or turpentine or soap, to form an emulsion with 
 the oil. Oxalic acid may be used to clean these 
 metals, but it must be rinsed or rubbed off com- 
 pletely, or green salts will be formed. Copper or 
 brass articles cleaned with acids tarnish much more 
 quickly from the action of moisture in the air than 
 when cleaned with the oil and soft powder. Small 
 spots may be removed with a bit of lemon juice and 
 hot water. An occasional rubbing with kerosene 
 helps to keep all copper articles clean and bright. 
 Indeed, kerosene is useful on any metal, as well as 
 on wood or glass. ^ 
 
 The presence of water always favors chemical 
 change. Therefore iron a*hd steel rapidly oxidize 
 in damp air or in the presence of moisture. All 
 metallic articles may be protected from. such action 
 by a thin oily coating. Iron and steel articles not in 
 use may be covered with a thin layer of vaseline. 
 
COOKING AND CLEANING. 
 
 11? 
 
 Rust spots may be scoured off with emery and 
 oil, covered with kerosene or sweet oil for some 
 time and then rubbed hard, or in obstinate cases, 
 touched with muriatic acid and then with ammonia, 
 to neutralize the acid. 
 
 A stove rubbed daily with a soft cloth and a few 
 drops of kerosene or sweet oil may be kept black 
 and clean, though not polished. Substances spilled 
 on such a stove may be cleaned off with soap and 
 water better than on one kept black with graphite. 
 
 Nickel is now used in stove ornaments, in the 
 bathroom, and in table utensils. It does not oxidize 
 or tarnish in the air or with common use. It can 
 be kept bright by washing in hot soap-suds and 
 rinsing in very hot water. It may be rubbed with 
 a paste of whiting and lard, tallow, alcohol or am- 
 monia. 
 
 Aluminum does not tarnish readily, and may be 
 rubbed with the whiting or with any of the fine 
 materials used for silver. It is darkened by 
 alkalies. 
 * Kitchen utensils, with careful use, may be kept 
 clean by soap and water or a liberal use of am- 
 monia. Fine sand-soap must occasionally be used 
 when substances are burned on or where the tin 
 comes in contact with flame. Kerosene is a good 
 cleaner for the zinc stove-boards; vinegar and 
 water, if there is careful rinsing afterward, or a 
 strong solution of salt and water may be used. 
 
 Iron-rust. 
 
 Care of 
 Stoves. 
 
 Nickel. 
 
 Aluminum. 
 
 Kitchen 
 Utensils. 
 
T 
 
 CHAPTER IV. 
 Laundry. 
 
 HE health of the family depends largely upon 
 the cleansing operations which belong to the 
 laundry. Here, too, more largely perhaps than in 
 any other line of cleaning, will a knowledge of 
 chemical properties and reactions lead to econ- 
 omy of time, strength and material. 
 
 The numerous stains and spots on table linen 
 and white clothes are dealt with in the laundry, 
 and, also, all fabrics soiled by contact with the 
 body. 
 
 Body clothes, bed linen and towels become 
 soiled not only by the sweat and oily secretions of 
 the body, but also with the dead organic matter 
 continually thrown off from its surface. Thus the 
 cleansing of such articles means the removal of 
 stains of varied character, grease and dust, and all 
 traces of organic matter. 
 
 The two most important agents in this purifica- 
 tion are water and soap, 
 water. Pure water is a chemical compound of two 
 
 gases, hydrogen and oxygen (H 2 0). It has great 
 solvent and absorbent power, so that in nature 
 pure water is never found, though that which falls 
 
COOKING AND CLEANING. 119 
 
 in sparsely-settled districts, at the end of a long 
 storm, may be approximately pure. The first fall 
 of any shower is mixed with impurities which have 
 been washed from the air. Among these may be 
 acids, ammonia and carbon in the form of soot 
 and creosote. It is these impurities which cause 
 the almost indelible stain left when rain-water 
 stands upon window-sills or other finished wood. 
 
 Cistern water, while soft, is liable to be colored wate r and Soft 
 from shingles, paint or moss on the roof. Spring 
 water and well water, having percolated a greater 
 or less distance through the ground, are filtered, 
 clear waters. But they have become mineralized 
 to a degree because of the great solvent power 
 of water. All ground waters contain more solid 
 residue than rain water, and are more or less 
 hard when they contain compounds of lime and 
 magnesia. These form insoluble compounds 
 with soap and give curd-like masses on hands 
 or clothes. They waste the soap, therefore, in 
 proportion to the amount present. 
 
 The soft waters of the Atlantic seaboard use 
 up very little soap. One pound of standard Cas- 
 tile softens 409 gallons of water containing 
 twenty parts per million of hardening sub- 
 stances; one pound of Ivory soap softens 196 
 gallons of the same water, and one pound of 
 Gold Dust 65 gallons. 
 
120 
 
 THE CHEMISTRY OF 
 
 Temporary 
 and 
 
 Permanent 
 Hardness. 
 
 Soap. 
 
 In case of a moderately hard water, not uncom- 
 mon in wells, giving 200 parts hardness per 
 million, one pound of Castile soap softens 60 
 gallons, one pound of Ivory soap 29 gallons, and 
 one pound of Gold Dust 24 gallons. Therefore 
 the expense of securing a soft water supply is 
 partly met by a saving in soap. 
 
 Many hard waters may be softened by boiling. 
 The gaseous carbon dioxide escapes and calcium 
 carbonate falls to the bottom of the vessel. Or 
 the excess gas may be taken up by lime water in 
 the cold. Such hardness is often called tempo- 
 rary, because it may be removed easily. 
 
 Permanent hardness is given by sulphates, 
 chlorides, nitrates of calcium, which require 
 chemical action to remove. Such compounds 
 are converted into carbonates by the addition of 
 sal-soda, soda-ash, sodium carbonate, which gives 
 the precipitate of calcium carbonate and the 
 soluble sodium sulphate. Tri-sodium phosphate 
 may be used instead of the carbonate, and 
 calcium phosphate precipitated. 
 
 In many parts of the country city supplies are 
 "softened" by chemical treatment. 
 
 Another important material used in the laundry 
 is soap. "Whether the extended use of soap be 
 preceded or succeeded by an improvement in any 
 community — whether it be the precursor or the re- 
 
COOKING AND CLEANING. 121 
 
 suit of a higher degree of refinement among the 
 nations of the earth — the remark of Liebig must 
 be acknowledged to be true, that the quantity of 
 soap consumed by a nation would be no inaccur- 
 ate measure whereby to estimate its wealth and 
 civilization. Of two countries with an equal 
 amount of population, the wealthiest and most 
 highly civilized*will consume the greatest weight 
 of soap. This consumption does not subserve sen- 
 sual gratification, nor depend upon fashion, but 
 upon the feeling of the beauty, comfort and wel- 
 fare attendant upon cleanliness; and a regard to 
 this feeling is coincident with wealth and civiliza- 
 tion."* 
 
 Many primitive people find a substitute for soap soap Substi. 
 in the roots, bark or fruit of certain plants. Nearly 
 every country is known to produce such vegetable 
 soaps, the quality which they possess of forming 
 an emulsion with oily substances being due to a 
 peculiar vegetable substance, known as Saponin. 
 Many of these saponaceous barks, roots and fruits 
 are now used with good results — the "soap bark" 
 of the druggist being one of the best substances 
 for cleansing dress goods, especially black, wheth- 
 er of silk or wool. 
 
 The fruit of the soapberry tree — Papindus 
 Saponaria — a native of the West Indies, is said to 
 
 * Muspratt's Chemistry as Applied to Arts and Matiufactures. 
 
 tutes. 
 
122 
 
 THE CHEMISTRY OF 
 
 Composition 
 of Soaps. 
 
 " Potash" and 
 " Soda." 
 
 be capable of cleansing as much linen as sixty 
 times its weight of soap. 
 
 Wood ashes were probably used as cleansing 
 material long before soap was made, as well as 
 long after its general use. Their properties and 
 value will be considered later. 
 
 Soaps for laundry use are chiefly composed of 
 alkaline bases, combined with fatty acids. Their 
 action is ''gently but efficiently to dispose the 
 greasy dirt of the clothes and oily exudations of 
 the skin to miscibility with, and solubility in wash 
 water."* 
 
 Oily matters, as we have seen, are soluble in cer- 
 tain substances, as salt is soluble in water, and can 
 be recovered in their original form from such solu- 
 tions by simple evaporation. Others in contact 
 with alkalies, form emulsions in which the sus- 
 pended fatty globules make the liquid opaque, as 
 in soapsuds. The soap is decomposed by water, 
 the alkali set free acts upon the oily matter on the 
 clothes, and unites with it, forming a new soap. 
 The freed fatty acid remains in the water, causing 
 the "milkiness," or is deposited upon the clothes. 
 
 Certain compounds of two of the alkali metals, 
 potassium and sodium, are capable of thus saponi- 
 fying fats and forming the complex substances 
 known as soaps. For the compounds of these al- 
 
 * Chemistry applied to the Manufacture of Soaps and Candles,— Morfit. 
 
COOKING AND CLEANING. 123 
 
 kalies employed in the manufacture of soap, we 
 shall use the popular terms "potash" and "soda," as 
 less likely to cause confusion in our readers' minds. 
 Potash makes soft soap; soda makes hard soap. 
 Potash is derived from wood ashes, and in the 
 days of our grandmothers soft soap was the uni- 
 versal detergent. Potash (often called pearlash) 
 was cheap and abundant. The wood fires of every 
 household furnished a waste product ready for its 
 extraction. Aerated pearlash (potassium bicar- 
 bonate), under the name of saleratus, was used for 
 bread. Soda-ash was, at that time, obtained from 
 the ashes of seaweed, and, of course, was not com- 
 mon inland. 
 
 The discovery by the French manufacturer, Le- 
 blanc, of a process of making soda-ash from the 
 cheap and abundant sodium chloride, or common 
 salt, has quite reversed the conditions of the use 
 of the two alkalies. Potash is now about eight 
 cents a pound, soda-ash is only three. 
 
 In 1824, Mr. James Muspratt, of Liverpool, first Manufacture 
 carried out the Leblanc process on a large scale, 
 and he is said to have been compelled to give 
 away soda by ,he ton to the soap-boilers, before 
 he could convince them that it was better than the 
 ashes of kelp, which they were using on a small 
 scale. The soap trade, as we now know it, came 
 into existence after the soap-makers realized the 
 
124 THE CHEMISTRY OF 
 
 value of the new process. Soda-ash is now the 
 cheapest form of alkali, and housekeepers will do 
 well to remember this fact when they are tempted 
 
 to buy some new " ine" or "Crystal." 
 
 In regard to the best form in which to use the 
 alkali for washing purposes, experience is the best 
 guide, — that is, experience reinforced by judg- 
 ment; for the number of soaps and soap substi- 
 tutes in the market is so great, and the names so 
 little indicative of their value, that only general in- 
 formation can be given. 
 
 In the purchase of soap, it is safest to choose 
 the make of some well-known and long-established 
 firm, of which there are several who have a repu- 
 tation to lose, if their products are not good ; and, 
 for an additional agent, stronger than soap, it is 
 better to buy sal-soda or soda-ash (sodium car- 
 bonate) and use it knowingly, than to trust to the 
 highly-lauded packages of the grocery. 
 The use of Washing soda should never be used in the solid 
 
 Washing ° 
 
 Soda. form, but should be dissolved in a separate vessel, 
 
 and the solution used with judgment. The in- 
 judicious use of the solid is probably the cause of 
 the disfavor with which it is often regarded. One 
 of the most highly recommended of the scores of 
 "washing compounds" formerly in the market, 
 doubtless owed its popularity to the following di- 
 rections: "Put the contents of the box into one 
 
COOKING AND CLEANING. 125 
 
 quart of boiling water, stir well, and add three 
 quarts of cold water; this will make one gallon. 
 For washing clothes, allow two cupfuls of liquid 
 to a large tub of water." 
 
 As the package contained about a pound of 
 washing soda, this rule, which good housekeepers 
 have found so safe, means about two ounces to a 
 large tub of water, added before the clothes are 
 put in. 
 
 Ten pounds of washing soda can be purchased 
 of the grocer for the price of this one-pound pack- 
 age with its high-sounding name. Nearly all the 
 compounds in the market depend upon washing 
 soda for their efficiency. Usually they contain 
 nothing else. Sometimes soap is present and, 
 rarely, borax. In one or two, a compound of am- 
 monia has been found. 
 
 Ammonia may be used with soap or as its sub- Ammonia 
 stitute. The ammonia ordinarily used in the house- 
 hold is an impure article and its continued use yel- 
 lows bleached fabrics. The pure ammonia may be 
 bought of druggists or of dealers in chemical sup- 
 plies and diluted with two or even four parts of 
 water. Borax, where the alkali is in a milder form 
 than it is in washing soda, is an effectual cleanser, 
 disinfectant and bleacher. It is more expensive 
 than soda or ammonia, but for delicate fabrics and 
 for many colored articles it is the safest alkali in 
 use. 
 
126 
 
 THE CHEMISTRY OF 
 
 Removal of 
 Stains. 
 
 Fruit-Stains. 
 
 Turpentine also is valuable in removing grease. 
 A tablespoonful to a quart of warm water is a sat- 
 isfactory way of washing silks and other delicate 
 materials. It should never be used in hot water, 
 for much would be lost by evaporation, and in this 
 form it is more readily absorbed by the skin, caus- 
 ing irritation and discomfort. 
 
 Preparation for General Washing. 
 
 White goods are liable to stains from a variety 
 of sources. Many of these substances when acted 
 upon by the moisture of the air, by dust, or al- 
 kalies, change their character, becoming more or 
 less indelible; colorless matters acquire color and 
 liquids become semi-solid. All such spots and 
 stains should be taken out before the clothes are 
 put into the general wash to be treated with soap. 
 
 Fruit stains are the most frequent and possibly 
 the most indelible, when neglected. These should 
 be treated when fresh. 
 
 The juices of most fruits contain sugar in solu- 
 tion, and pectose, a mucilaginous substance which 
 will form jelly. All such gummy, saccharine mat- 
 ters are dissolved most readily by boiling water, 
 as are mucilage, gelatine and the like. To remove 
 them when old, an acid, or in some cases, a 
 bleaching liquid, like "chloride of lime" solution or 
 Javelle water will be needed. 
 
COOKING AND CLEANING. 
 
 127 
 
 Stretch the stained part over an earthen dish and 
 pour boiling water upon the stain until it disap- 
 pears. How to use the acid and the Javelle water 
 will be explained later on. 
 
 Wine stains should be immediately covered 
 with a thick layer of salt. Boiling milk is often 
 used for taking out wine and fruit stains. 
 
 Most fruit stains, especially those of berries, are 
 
 bleached readily by the fumes of burning sulphur. 
 
 S0 2 . These fumes are irritating to the mucous 
 
 membrane and care should, therefore, be taken 
 
 not to inhale them. Stand by an open window 
 
 and turn the head away. Make a cone of stiff 
 
 paper or cardboard or devote a small tin tunnel to 
 
 this purpose. Cut off the base of the paper cone, 
 
 leaving it level and have a small opening at the 
 
 apex. On an old plate or saucer, place a small 
 
 piece of sulphur, set it on fire, place over it the 
 
 cone or tunnel, and hold the moistened stain over 
 
 the chimney-like opening. Have a woolen cloth 
 
 handy to put out the sulphur flame if the piece is 
 
 larger than is needed. A burning match sometimes 
 
 furnishes enough S0 2 for small spots. Do not get 
 
 the burning sulphur on the skin. 
 
 Medicine stains usually yield to alcohol. Iodine 
 dissolves more quickly in ether or chloroform. 
 
 Coffee, tea and cocoa stain badly, the latter, if 
 neglected, resisting even to the destruction of the 
 
 Use of Sul- 
 phur Fumes 
 
 Medicine. 
 
 Tea, Coffee, 
 Cocoa. 
 
128 THE CHEMISTRY OF 
 
 fabric. These all contain tannin, besides various 
 coloring matters. These coloring matters are 
 "fixed" by soap and hot water. Clear boiling 
 water will often remove fresh coffee and tea stains, 
 although it is safer to sprinkle the stain with borax 
 and soak in cold water first. (A dredging box 
 filled with borax is a great convenience in the laun- 
 dry.) Old cocoa and tea stains may resist the bo- 
 rax. Extreme cases require extreme treatment. 
 Place on such stains a small piece of washing- 
 soda or "potash." Tie it in and boil the cloth for 
 half an hour. It has already been said that these 
 strong alkalies in their solid form cannot be al- 
 lowed to touch the fabrics without injury. With 
 this method, then, there must be a choice between 
 the stain and an injury to the fabric, 
 javeiie Water. An alkaline solution of great use and conven- 
 ience is Javelle water. It will remove stains and 
 is a general bleacher. This is composed of one 
 pound of sal-soda with one-quarter pound of 
 "chloride of lime" — calcium hypochlorite — in two 
 quarts of boiling water. Let the substances dis- 
 solve as much as they will and the solution cool and 
 settle. Pour off the clear liquid and bottle it for 
 use. Be careful not to let any of the solid portion 
 pass into the bottle. Use the dregs to scour un- 
 painted woodwork, or to cleanse waste pipes. 
 When a spot is found on a white table-cloth, 
 
COOKING AND CLEANING. l2d 
 
 place under it an overturned plate. Apply Javelle 
 water with a soft tooth-brush. (The use of a brush 
 protects the skin and nails.) Rub gently till the 
 stain disappears, then rinse in clear water and 
 finally in ammonia. "Chloride of lime" always 
 contains a powerful acid, as well as some free 
 chlorine. 
 
 Blood stains require clear, cold or tepid water, Blood, 
 for hot water and soap render the red coloring 
 matter less soluble. When the stain is brown and 
 nearly gone, soap and hot water may be used. 
 
 Meat juice on the table linen is usually com- 
 bined with more or less fat. This also yields most 
 readily to the cold water, followed by soap. 
 
 Stains made by mucus should be washed in am- 
 monia before soap is added. When blood is mixed 
 with mucus, as in the case of handkerchiefs, it 
 is well to soak the stains for some hours in a solu- 
 tion of salt and cold water — two tablespoonfuls to 
 a quart. Double the quantity of salt for heavier 
 or more badly stained articles. The salt has a dis- 
 infecting quality, and its use in this way is a wise 
 precaution in cases of catarrh. 
 
 Milk exposed to the air becomes cheesy, and Milk, 
 hot water with milk makes a substance difficult of 
 solution. Milk stains, therefore, should be washed 
 out when fresh and in cold water. 
 
 Grass stains dissolve in alcohol. If applied im- Grass. 
 
130 THE CHEMISTRY OF 
 
 mediately, ammonia and water will sometimes 
 wash them out. In some cases the following meth- 
 ods have proved successful, and their simplicity 
 recommends them for trial in cases where colors 
 might be affected by alcohol. Molasses, or a paste 
 of soap and cooking soda, may be spread over the 
 stain and left for some hours, or the stain may be 
 kept moist in the sunshine until the green color 
 has changed to brown, then it will wash out in 
 clear water. 
 
 Mildew. Mildew causes a spot of a totally different char- 
 
 acter from any we have considered. It is a true 
 mold, and like all plants requires warmth and 
 moisture for its growth. When this necessary 
 moisture is furnished by any cloth in a warm 
 place, the mildew grows upon the fibres. During 
 the first stages of its growth, the mold may be 
 removed, but in time it destroys the fibres. 
 
 Strong soapsuds, a layer of soft soap and pulver- 
 ized chalk, or one of chalk and salt, are all effec- 
 tive if, in addition, the moistened cloth be sub- 
 jected to strong sunlight, which kills the plant 
 and bleaches the fibres. Bleaching powder or 
 Javelle water may be tried in cases of advanced 
 growth, but success cannot be assured. 
 
 °* 1 - Some of the animal and vegetable oils may be 
 
 taken out by soap and cold water or dissolved in 
 naphtha*, chloroform, ether, etc. 
 
COOKING AND CLEANING. 131 
 
 Some of the vegetable oils are only sparingly 
 soluble in cold, but readily soluble in hot alcohol. 
 The boiling point of alcohol is so low that care 
 should be taken that the temperature be not raised 
 to the ignition point. 
 
 Mineral oil stains are not soluble in any alkaline 
 or acid solutions. Kerosene will evaporate in time. 
 Vaseline stains should be soaked in kerosene be- 
 fore water and soap touch them. 
 
 Ink spots on white goods are the same in charac- ink. 
 ter as on colored fabrics. Many of the present inks 
 are made from aniline or allied substances instead 
 of the iron compounds of the past. Aniline black 
 is indelible; the colored anilines may be dissolved in 
 alcohol. Where the ink is an iron compound the 
 stain may be treated with oxalic, muriatic or hot 
 tartaric acids, applied in the same manner as for 
 iron-rust stains. No definite rule can be given, for 
 some inks are affected by strong alkalies, others by 
 acids, while some will dissolve in clear water. 
 
 The present dyes are so much more stable than 
 those of twenty-five years ago, that pure lemon 
 juice or a weak acid like hydrochloric, has no effect 
 upon many colors. Any acid should, however, be 
 applied with caution. If the color is affected by 
 acids, it may often be restored by dilute ammonia. 
 
 The red iron-rust spots must be treated with acid. Red Ir ° Q - 
 These are the result of true oxidation — the union 
 
 rust. 
 
132 THE CHEMISTRY OF 
 
 of the oxygen of the air with the iron in the pres- 
 ence of moisture. The salt formed is deposited 
 upon the fabric which furnishes the moisture. Or- 
 dinary "tin" utensils are made from iron coated 
 with tin, which soon wears off, so no moist fabric 
 should be left long in tin unless the surface is entire. 
 
 Iron-rust is, then, an oxide of iron. The oxides 
 of iron, copper, tin, etc., are insoluble. The chlor- 
 ides, however, are soluble. Replace the oxygen 
 with the chlorine of hydrochloric acid and the iron 
 compound will be dissolved. The method of apply- 
 ing the acid is very simple. 
 
 Fill an earthen dish two thirds full of hot water 
 and stretch the stained cloth over this. Have near 
 two other dishes with clear water in one and am- 
 monia water in the other. The steam from the hot 
 water will furnish the heat and moisture favorable 
 for chemical action. Drop a little hydrochloric 
 (muriatic) acid, HC1, on the stain with a medicine 
 dropper. Let it act a moment, then lower the cloth 
 into the clear water. Repeat till the stain disap- 
 pears. Rinse carefully in the clear water and, 
 finally, immerse in the ammonia water that any ex- 
 cess of acid may be neutralized and the fabric pro- 
 tected. 
 
 Salt and lemon juice are often sufficient for a 
 slight stain, probably because a little hydrochloric 
 acid is formed from their union. 
 
COOKING AND CLEANING. 133 
 
 Many spots appear upon white goods which re- Bluing, 
 semble those made by iron-rust, or the fabrics 
 themselves acquire a general yellowish tinge. This 
 is the result of the use of bluing and soap, where 
 there has been imperfect rinsing of the clothes. 
 The old-time bluing was pure indigo. This is in- 
 soluble, but, by its use, a fine blue powder was 
 spread among the fibres of the cloth. It required 
 careful manipulation, which it usually had. Indigo 
 with sulphuric acid can be made to yield a soluble 
 paste. This is the best form of bluing which can 
 be used, for a very little gives a dark, clear blue to 
 water, and overcomes the yellowish tinge which 
 cotton or linen will acquire in time unless well 
 bleached by sunshine. The expense and difficulty 
 of obtaining this soluble indigo has led to the sub- 
 stitution of numerous solid and liquid "blues" by 
 the use of which the laundress is promised success 
 with little labor. Most of these liquid bluings con- 
 tain some iron compound. This, when in contact 
 with a strong alkali, is broken up and the iron is 
 precipitated. If, then, bluing be used where all the 
 soap or alkali has not been rinsed from the clothes, 
 this decomposition and precipitation takes place, 
 and a deposit of iron oxide is left on the cloth. This 
 must be dissolved by acid like any iron-rust. 
 
 Some "blues" are compounds of ultramarine, a 
 brilliant blue silicate of aluminum. These are gen- 
 
134 THE CHEMISTRY OF 
 
 erally used in the form of a powder which is insol- 
 uble, settles quickly and, thereby, leaves blue spots 
 or streaks. It is very difficult to prevent these when 
 insoluble powdered "blues" are used. This silicate 
 combined with hydrochloric acid forms a jelly-like 
 mass from which a white precipitate is formed. 
 These ultramarine blues are sometimes recom- 
 mended because of this white precipitate, obviating, 
 as is said, the yellowish results of careless rinsing, 
 inevitable when iron "blues" are used. The advice 
 is misleading, for no precipitate is formed unless an 
 acid be added. 
 
 When solid bluing is used it should be placed in 
 a flannel bag and stirred about in a basin of hot 
 water. In this way only the finest of the powder is 
 obtained. After this blued water is poured into the 
 tub, it must be continually stirred, to prevent the 
 powder from settling in spots or streaks upon the 
 clothes. 
 Bleaching. First, then, the removal of all dirt, and second, 
 
 the removal, by thorough rinsing, of all soap or 
 other alkalies used in the first process, and third, 
 long exposure to air and sunshine should render 
 the use of bluing unnecessary. The experience of 
 many shows that clothes that have never been 
 blued, never need bluing. In cities where conveni- 
 ences for drying and bleaching in the sunshine are 
 few, and where clear water or clear air are often un- 
 
COOKING AND CLEANING. 135 
 
 attainable, a thorough bleaching two or three times 
 a year is a necessity ; but in the country it is wiser to 
 abolish all use of bluing and let the great bleacher, 
 the sun, in its action with moisture and the oxygen 
 of the air, keep the clothes white as well as pure. 
 
 Freezing aids in bleaching, for it retains the 
 moisture, upon which the sun can act so much the 
 longer. The easiest household method of bleach- 
 ing where clean grass, dew and sunshine are not 
 available, is by the use of "bleaching powder." In 
 the presence of water and weak acids, even carbonic 
 acid, oxygen and chlorine are both set free from 
 the compound. At the moment of liberation the 
 action is very powerful. The organic coloring mat- 
 ters present are seized upon and destroyed, thereby 
 bleaching the fabric. 
 
 Directions for the use of the powder usually ac- 
 company the can in which it is bought. The woman 
 who knows that the acid always present in the pow- 
 der must be completely rinsed out or neutralized 
 by an alkali, may use her bleaching powder with 
 safety and satisfaction. 
 
 All special deposits should be removed before General 
 the general cleansing of the fabric is undertaken. 
 Grease and other organic matters are the undesir- 
 able substances which are to be disposed of in the 
 general cleansing. Grease alone is more quickly 
 acted upon by hot water than by cold, but other 
 
 Cleansing. 
 
136 
 
 THE CHEMISTRY OF 
 
 Soaking. 
 
 Boiling. 
 
 Yellowness. 
 
 organic matter is fixed by the hot water. There- 
 fore, while hot water melts the grease quickly, the 
 mixture may be thus spread over the surface and 
 may not be removed by the soap. 
 
 An effective method, proved by many housewives 
 of long experience, is to soap thoroughly the dirti- 
 est portions of the clothes, fold these together 
 toward the center, roll the whole tightly, and soak 
 in cold water. The water should just cover the 
 articles. In this way the soap is kept where it is 
 most needed, and not washed away before it has 
 done its work. When the clothes are unrolled the 
 dirt may be washed out with less rubbing. 
 
 Too long soaking when a strong soap is used, 
 which has much free alkali, would weaken the fab- 
 ric. Judgment, trained by experience must guide 
 in such cases, so that effective cleaning depends 
 upon careful manipulation. 
 
 Whether to boil or not to boil the clothes de- 
 pends largely upon the purity of the materials used 
 and the degree of care exercised. Many persons 
 feel that the additional disinfection which boiling 
 ensures is an element of cleanness not to be disre- 
 garded ; others think it unnecessary under ordinary 
 conditions, while others insist that boiling yellows 
 the clothes. 
 
 The causes of this yellowness seem to be: 
 
COOKING AND CLEANING. 
 
 137 
 
 Impure materials in the soap used ; 
 
 The deposition, after a time, of iron from the 
 water or the boiler; 
 
 The imperfect washing of the clothes — that is, 
 the organic matter is not thoroughly removed. 
 
 The safest process seems to be to put the clothes 
 into cold water with little or no soap, let the tem- 
 perature rise gradually to the boiling point and 
 remain there a few minutes. 
 
 Soap is more readily dissolved by hot water than 
 by cold, hence the boiling should help in the com- 
 plete removal of the soap and may well precede the 
 rinsing. 
 
 Borax — A tablespoonful to every gallon of 
 water — added to each boilerful serves as a bleacher 
 and an aid in disinfection. The addition of the 
 borax to the last rinsing water is preferred by 
 many. In this case, the clothes should be hung out 
 quite wet, so that the bleaching may be thorough. 
 
 "Scalding," or the pouring of boiling water over 
 the clothes is not so effectual for their disinfec- 
 tion as boiling, because the temperature is so 
 quickly lowered. 
 
 The main points in laundry cleansing seem to 
 be:— 
 
 The removal of all stains; 
 
 Soft water and a good quality of soap; 
 
 The use of strong alkalies in solution only; 
 
 Scalding. 
 
 Necessities 
 for Good 
 Cleansing, 
 
138 
 
 THE CHEMISTRY OF 
 
 Linen. 
 
 Not too hot nor too much water while the soap 
 is acting upon the dirt; much water to wash in; 
 
 Thorough rinsing, that all alkali may be re- 
 moved; and that no dirty water remain: 
 
 Long exposure to sunlight — the great bleacher 
 and disinfectant. 
 
 The fibres of cotton, silk and wool vary greatly 
 in their structure, and a knowledge of this struc- 
 ture, as shown under the microscope, may guide 
 to proper methods of treatment. 
 
 The fibres of cotton, though tubular, become 
 much flattened during the process of manufacture, 
 and under the microscope show a characteristic 
 twist, with the ends gradually tapering to a point. 
 It is this twist which makes them capable of being 
 made into a firm, hard thread. 
 
 The wool fibre, like human hair, is marked by 
 transverse divisions, and these divisions are ser^ 
 rated. These teeth become curled, knotted or 
 tangled together by rubbing, by very hot water, or 
 by strong alkalies. This causes the shrinking which 
 should be prevented. When the two fibres are 
 mixed there is less opportunity for the little teeth 
 to become entangled and, therefore, there is less 
 shrinkage. 
 
 Linen fabrics are much like cotton, with slight 
 notches or joints along the walls. These notches 
 serve to hold the fibres closely together and enable 
 
COOKING AND CLEANING. 139 
 
 them to be felted to form paper. Linen, then, will 
 shrink, though not so much as wool, for the fibres 
 are more wiry and the teeth much shorter. 
 
 Silk* fibres are perfectly smooth, and when silk, 
 rubbed, simply slide over each other. This pro- 
 duces a slight shrinkage in the width of woven 
 fabrics. 
 
 All wool goods, then, require the greatest care $ as ^ of 
 in washing. The different waters used should be of 
 the same temperature, and never too hot to be 
 borne comfortably by the hand. 
 
 The soap used should be in the form of a thin 
 soap solution. No soap should be rubbed on the 
 fabric, and only a good white soap, free from rosin, 
 or a soft potash soap, is allowable. Make each 
 water slightly soapy and leave a very little in the 
 fabric at the end, to furnish a dressing as nearly 
 like the original as possible. 
 
 Many persons prefer ammonia or borax in place 
 of the soap. For pure white flannel, borax gives the 
 best satisfaction, on account of its bleaching qual- 
 ity. Whatever alkali is chosen, care should be ex- 
 ercised in the quantity taken. Only enough should 
 be used to make the water very soft. 
 
 The fibres of wool collect much dust upon their 
 tooth-like projections, and this should be thor- 
 oughly brushed or shaken off before the fabric 
 is put into the water. All friction should be by 
 
140 THE CHEMISTRY OF 
 
 squeezing, not by rubbing. Wool should not be 
 wrung by hand. Either run the fabric smoothly 
 through a wringer or squeeze the water out, that 
 the fibres may not be twisted. Wool may be well 
 dried by rolling the article tightly in a thick dry 
 towel or sheet and squeezing the whole till all 
 moisture is absorbed. Wool should not be allowed 
 to freeze, for the teeth will become knotted and 
 hard. 
 
 Linen, like wool, collects much dirt upon the 
 surface which does not penetrate the fabric. Shake 
 this off and rub the cloth as little as possible. 
 Linen or woolen articles should not be twisted in 
 the drying process, as it is sometimes impossible 
 to straighten the fibres afterward, 
 setting of Colored cottons should have their colors fixed 
 
 Colors. 
 
 before washing. Salt will set most colors, but the 
 process must be repeated at each washing. Alum 
 sets the colors permanently, and at the same time 
 renders the fabric less combustible, if used in 
 strong solution after the final rinsing, 
 very Dirty Dish cloths and dish towels must be kept clean 
 
 Aiticles. 
 
 as a matter of health, as well as a necessity for 
 clean, bright tableware. The greasy dish cloth 
 furnishes a most favorable field for the growth 
 of germs. It must be washed with soap and hot 
 water and dried thoroughly each time. All such 
 cloths should also form a part of the weekly 
 
COOKING AND CLEANING. 
 
 141 
 
 wash and be subjected to all the disinfection pos- 
 sible, with soap, hot water and long drying in sun- 
 shine and the open air. Beware of the disease- 
 breeding, greasy and damp dish cloth hung in a 
 warm, dark place! 
 
 Oven towels, soiled with soot and crock, may be 
 soaked over night, or for some hours, in just kero- 
 sene enough to cover, then washed in cold water 
 and soap. 
 
 With very dirty clothes or for spots, where hard 
 rubbing is necessary, much strength may be saved 
 by using a scrubbing brush. 
 
 Laundry tubs should be carefully washed and 
 dried. Wooden tubs, if kept in a very dry place, 
 and turned upside down, may have the bottoms 
 covered with a little water. 
 
 The rubber rollers of the wringer may be kept 
 white by rubbing them with a clean cloth and a 
 few drops of kerosene. 
 
 All waste and overflow pipes, from that of the 
 kitchen sink to that of the refrigerator, become 
 foul with grease, lint, dust, and other organic mat- 
 ters that are the result of bacterial action. They 
 are sources of contamination to the air of the en- 
 tire house and to the food supply, thereby endan- 
 gering health. All bath, set-bowl and watei closet 
 pipes should be flushed generously once a day, at 
 least, the kitchen sink pipe with clear boiling 
 
 Care of Laun« 
 dry Furni- 
 ture. 
 
 Care of 
 Plumbing. 
 
142 THE CHEMISTRY OF 
 
 water; and once a week all pipes should have a 
 thorough cleaning- with a strong boiling solution 
 of washing-soda and a monthly flushing with caus- 
 tic potash. The plumbers recommend the "stone" 
 or crude potash for the kitchen pipe. This, is 
 against their own interests, for many a plumber's 
 bill is saved where the housewife knows the dan- 
 ger and the means of prevention of a grease-coated 
 sink drain. The pipe of the refrigerator should be 
 cleared throughout its entire length with the soda 
 solution. Avoid any injury to the metallic rims of 
 the waste pipes by using a large tunnel. 
 
 Old-fashioned styles of overflow pipes retain a 
 large amount of filth, and it is very difficult to dis- 
 lodge it. A common syringe may be devoted to 
 this purpose. By its patient, frequent use even this 
 tortuous pipe may be kept clean. 
 
 Ideal Cleanness. 
 Sanitary Ideal cleanness requires the cleanness of the in- 
 
 Clcanness. n 
 
 dividual, of his possessions, and of his environ- 
 ment. Each individual is directly responsible for 
 his personal cleanness and that of his possessions; 
 but over a large part of his environment he has 
 only indirect control. Not until direct personal 
 responsibility is felt in its fullest sense, and exer- 
 cised in all directions toward the formation and 
 carrying out of sufficient public laws, will sanitary 
 
COOKING AND CLEANING. 
 
 143 
 
 cleanness supplant the cure of a large number of 
 diseases by their prevention. 
 
 Many of the diseases of childhood are directly 
 traceable to uncleanness, somewhere. By these dis- 
 eases the system, is often so weakened that others 
 of different character are caused which, though 
 slow in action, may baffle all science in their cure. 
 
 The necessity of forming systematic habits of 
 cleanness in the young is the first step toward sani- 
 tary health. They should, then, step by step, as 
 they are able to grasp the reasons for the habits, 
 be educated in all the sciences which give them 
 the knowledge of the cause and effects of un- 
 cleanness, the methods of prevention and removal, 
 and the relation of all these to building laws and 
 municipal regulations. 
 
 The first environment to be kept clean is the 
 home. But personal cleanness and household 
 cleanness should not be rendered partially futile by 
 unclean schoolhouses, public buildings and streets. 
 
 The housekeeping of the schoolhouses, especially, 
 should be carried on with a high regard to all 
 hygienic details, since here the degree of danger 
 is even greater than in the home. In public 
 schoolhouses the conditions favorable to the pres- 
 ence of disease germs abound. If present, their 
 growth is rapid, and the extent of contagion be- 
 yond calculation. The cooperation of all most in- 
 
 Personal 
 Cleanness. 
 
 School-house 
 Sanitation. 
 
144 COOKING AND CLEANING. 
 
 terested — pupils and teachers — should be expected 
 and required as firmly as their cooperation in any 
 other department of education. 
 nes b s lic Qean " The sanitary condition of every school building 
 
 should be a model object lesson for the home; then, 
 instruction in personal cleanness will carry the 
 weight of an acknowledged necessity. 
 
 Schoolhouses which are models of sanitary clean- 
 ness will cause a demand for streets and public 
 conveyances of like character; then all public build- 
 ings will be brought under the same laws of evi- 
 dent wisdom. 
 
 Not till the right of cleanness is added to the 
 right to be well fed, and both are assured to each 
 individual by the knowledge and consent of the 
 whole people, can the greater gospel of prevention 
 make good its claims. 
 
CHAPTER V. 
 Chemicals and Their Use in the Household. 
 
 EVERY woman, whether she knows it or not, ExpSSLts 
 is every day performing simple experi- in the Home - 
 ments in chemistry. Every match that is lighted, 
 every use of soap on the body, the clothes or the 
 utensils, depends upon chemical laws for the 
 reactions which take place. 
 
 There is no process of cooking or cleaning 
 that does not rest upon a foundation of chemical 
 or physical law. Therefore every house is a 
 laboratory. Each is presided over by a director 
 of greater or less intelligence. 
 
 When intellectual interest and manual dex- 
 terity unite, "drudgery" is eliminated. 
 
 There may be, too, at all times an attitude of 
 discovery. Many of the most important chem- 
 ical processes have been found out, it is said, 
 accidentally. 
 
 In most persons an experiment awakens in- 
 terest. The housewife should be a cautious 
 experimenter. 
 
 An understanding of simple chemical reac- 
 tions tends also to economy in household 
 management. 
 
146 THE CHEMISTRY OF 
 
 The thrifty housewife may not only save many 
 dollars by restoring tarnished furniture and 
 stained fabrics, but may also keep her belongings 
 fresh and "as good as new" by the judicious use 
 of a few chemical substances always ready at her 
 hand. 
 
 It is essential, however, that she know their 
 properties and the effect they are likely to have 
 on the materials to be treated, lest more harm 
 than good result from their use. A good exam- 
 ple is the instant disappearance of all red iron- 
 rust stains when treated with a drop of hydro- 
 chloric acid. If, however, the acid is not com- 
 pletely washed out, the fabric will become eaten, 
 and holes will appear, which, in the housekeeper's 
 eye, are worse than the stains. This danger may 
 be entirely removed by adding ammonia to the 
 final rinsing water, which neutralizes any remain- 
 ing acid, and the stained tray-cloth or sheet is 
 perfectly whitened. 
 
 It is well that the household laboratory should 
 be supplied with the following substances. Not 
 all of these are strictly chemicals, but they are 
 included by courtesy, as it were, because so 
 closely connected with the chemical reactions. 
 Many of them act only mechanically. 
 Alkalies. I. Alkalies — substances with a soapy feeling 
 
 and which turn red litmus blue. In solutions 
 
COOKING AND CLEANING. 147 
 
 they neutralize the effects of acids. When the 
 neutralization is complete the solution is said to 
 be neutral, and it will not change the color of 
 litmus. This neutral substance is a chemical 
 salt. 
 
 Alkalies, except ammonia, injure wool fibres, 
 hardening, roughening and shrinking them, 
 while the caustic alkalies dissolve them. Only 
 weak alkalies should be used on linen or silk. 
 
 I. Potassium hydroxide, KOH, Caustic pot- Caustic Potash. 
 
 ash. This can be bought in solid form to use in 
 drains for removing grease. It forms a soap, 
 which must be washed out of the pipes by thor- 
 ough flushing. It is one of the strongest alkalies 
 and must be used with caution. It is dissolved 
 in water with the evolution of great heat, caus- 
 ing rapid boiling. Spatters from it on fabrics 
 are liable to burn holes, on wood will darken the 
 color, and on the flesh may cause deep burns. 
 When got upon the flesh or upon fabrics it 
 should be quickly washed off and, if necessary, 
 treated with vinegar. It is usually bought in 
 cans as " concentrated lye."* It combines with 
 fat to make soft soap. 
 
 Potassium is a common ingredient of inland 
 vegetation. Caustic potash is derived from wood 
 ashes. By adding water to wood ashes, potash 
 
 * Today, however, this is more often caustic soda than potash. 
 
148 THE CHEMISTRY* OF 
 
 (carbonate of potash) is dissolved and the result- 
 ing liquid, lye, may t>e used for purposes of 
 cleansing. 
 
 Many a country housewife " sweetens" the 
 tainted pork barrel, the butter firkin or pie plate 
 by soaking or boiling it with wood ashes. Ran- 
 cid fats are acid. This acidity can be neutral- 
 ized by the alkali. 
 
 Potash is often used to soften paint, shellac 
 and other woodwork finishes, to facilitate their 
 removal before refinishing. This has the disad- 
 vantage that the wood is darkened by the alkali 
 and the grain is raised. 
 Caustic soda. 2. Sodium hydroxide, NaOH, caustic soda. 
 
 This compound resembles caustic potash, is ef- 
 fective in slightly less degree for the same pur- 
 poses ; and, being cheaper, is much more exten- 
 sively used. The element sodium is common in 
 all marine and seashore plants, and is the metal 
 in common salt, from which it is now prepared. 
 Soda Ash. 3. Sodium carbonate, Na 2 C0 3 , soda-ash 
 
 (originally from the ashes of seaweed). When a 
 hot solution of soda-ash is cooled, a crystalline 
 form is left known as sal-soda, washing soda, 
 soda crystals. The crystals lose water when ex- 
 posed to the air and crumble to powder. This 
 powder is, therefore, stronger than the crystals. 
 
 Sal-soda is used most commonly in softening 
 
COOKING AND CLEANING. 149 
 
 hard water, for keeping the plumbing pipes free 
 from grease and to remove grease and hardened 
 food from cooking utensils. A convenient way 
 to prepare sal-soda for general use is to put one 
 pound of the ash in one quart of water. Let 
 this boil until the soda is dissolved. Bottle when 
 cold. It is the second strongest alkaline cleaner, 
 cheaper and more safely used than potash. 
 
 4. Sodium bicarbonate, NaHCO s , cooking cooking soda. 
 soda, carbonated soda-ash. In cooking it is used 
 
 to neutralize acids, to aerate dough and to pro- 
 duce effervescence in acid solutions by liberating 
 carbon dioxide. This is the saleratus of today. 
 The true saleratus or "pearlash" used seventy- 
 five years ago was the corresponding potassium 
 salt, KHCO3. This was often obtained by burn- 
 ing corncobs, mixing the ashes with water and 
 allowing the solution to evaporate to dryness. 
 
 In cleaning, sodium bicarbonate gives a mildly 
 alkaline action when dissolved in water. With 
 kerosene it is nearly insoluble and therefore 
 gives a soft friction. Used in this way it is 
 effective in scouring plumbing fixtures, where 
 the insoluble whiting might clog the pipes. For 
 cleaning purposes, the choice between borax and 
 bicarbonate would be one of their relative cost. 
 
 5. Borax, Na 2 B 4 4 . A weakly alkaline sub- Borax. 
 stance, most useful with hard water, as a 
 
150 THE CHEMISTRY OF 
 
 bleacher and as an antiseptic. It is much more 
 expensive than sal-soda, but is less liable to injure 
 fabrics and to irritate the skin. Its action on 
 colors is less than that of ammonia. 
 
 6. Ammonia. The gas NH S is dissolved in 
 water in varying proportions, forming ammo- 
 nium hydroxide, or aqua ammonia, NH 4 OH. It 
 is the only volatile alkali. It is a useful sub- 
 stance in nearly all cleaning processes, and to 
 neutralize acids. 
 
 "Household ammonia" is subject to impurities 
 due to processes of manufacture. These often 
 fade colors or cause white materials to turn yel- 
 low. It is safer and cheaper to buy the concen- 
 trated ammonia from a druggist or a dealer in 
 chemicals and add the water at home. This con- 
 centrated ammonia may be diluted one-half to 
 one-sixth and yet be sufficiently strong for most 
 uses. 
 
 It loses strength rapidly when open to the air, 
 therefore it should be bought in quantities pro- 
 portioned to its use, diluted one-half or more 
 and kept carefully corked. A glass stopper is 
 best, although rubber will serve. Cork is acted 
 upon by the fumes and will color the ammonia. 
 If the glass stopper tends to stick, it may be kept 
 slightly smeared with vaseline. 
 
 Ammonia should not be used on brass or 
 
COOKING AND CLEANING. 151 
 
 copper, as it eats them rapidly. It discolors 
 aluminum; but the resultant compound is not 
 injurious. 
 
 7. Soaps. Hard soap is sold in small cakes, Soaps - 
 shavings or powder; soft soap in semi-liquid, 
 
 or liquid soap solutions. There are many grades 
 from those that are neutral, like the best toilet 
 soaps, to those that have much free alkali. The 
 free alkali hastens the action, but is injurious to 
 the skin and to many other materials. Soap and 
 water has a greater solvent power than water 
 alone. 
 
 8. Ox-gall, the liquid contents of the gall- Ox-Gail, 
 bladder of beef creatures, is a natural soap. It 
 
 is excellent for cleaning colored fabrics. It may 
 be used clear or with tepid water. It decomposes 
 readily and, therefore, must be used while fresh. 
 
 II. Acids — substances with a sour taste and Acids - 
 which change blue litmus red. An acid will also 
 liberate carbon dioxide from cooking or washing 
 soda. In general, weak acids lighten the color 
 of wood, while strong acids burn it. Acids act 
 injuriously on all metals if allowed to remain in 
 contact with them. The metallic salts that are 
 formed are often very poisonous. 
 
 When used with caution acids are effectual in 
 removing iron and fruit stains. They remove 
 color from some fabrics. 
 
152 
 
 THE CHEMISTRY OF 
 
 Acetic Acid. 
 
 Lactic and 
 Citric Acids. 
 
 Dilute, cold, acid solutions do not readily in- 
 jure cotton or linen, while hot, strong solutions 
 injure the fibre. No acid should be allowed to 
 dry upon cloth. 
 
 I. Acetic acid, C 2 H 4 2 , is the acid of vinegar 
 and for many purposes it may be used in this 
 form. For delicate processes, however, the other 
 substances present may stain or interfere with 
 the action, so that the pure acetic acid, much 
 diluted, is better. It is volatile, therefore any 
 excess is not likely to injure the fabric by con- 
 centration in it on drying, as will hydrochloric 
 and oxalic acids. While acids clean copper and 
 brass quickly by combining with the tarnishing 
 salts, thus exposing a fresh surface, this new 
 surface soon tarnishes again, and the process 
 must be repeated. If any acid remains, as it is 
 likely to do in seams and grooves, metallic salts 
 will be formed. Copper acetate, which is formed 
 when brass or copper is treated with vinegar, is 
 very dangerous. 
 
 Sour milk contains lactic acid ; lemons, citric 
 acid, and this is perhaps the best natural acid to 
 use for cleaning purposes. It should be used 
 with caution, however, as it is strong enough to 
 affect some colors and reacts with metals, as 
 copper, brass and iron. Rhubarb, tomatoes, sor- 
 rel, etc., contain acid principles. They can be 
 
COOKING AND CLEANING. 153 
 
 used in emergencies and are less liable to "eat" 
 fabrics. 
 
 2. Oxalic acid, H 2 C 2 4 , is found naturally in OxaikAcid. 
 some plants, as oxalis and sorrel. It is bought 
 in crystals, which are quickly soluble in hot and 
 more slowly in cold water. It is very useful in 
 removing stains from white fabrics and may be 
 used on some colors (any acid to be used on 
 colored fabrics should be tested first on a piece 
 of the goods or on some hidden part, as a seam). 
 
 Hot solutions of oxalic acid are more effective 
 than cold. When very strong it makes the finger 
 nails brittle and may irritate the skin tempo- 
 rarily. It must be labeled "Poison," and should 
 be kept out of the reach of children. 
 
 N OTE —The strong acids destroy the coats of the stomach and there- 
 fore are poisonous in a general sense, although not in the strict sense in 
 which strychnine is. 
 
 3. Tartaric acid, H 2 (C 4 H 4 6 ), the acid of Tartaric Add. 
 cream of tartar, and prepared from it by treat- 
 ment with milk of lime, is one of the safest acid 
 
 agents. The Rochelle salt of Seidlitz powders 
 is a sodium potassium tartrate. In "soda pow- 
 ders" one paper contains tartaric acid, the other 
 sodium bicarbonate. The crude tartar or argol 
 is formed as a hard crust or deposit on the 
 bottom and sides of vessels in which wine is 
 manufactured. 
 
 4. Hydrochloric or muriatic acid, HC1, most K° chloric 
 
154 THE CHEMISTRY OF 
 
 valuable for removing iron stains from fabrics 
 and other materials. It sometimes injures silk 
 and must be used with caution on colored goods. 
 A twenty per cent solution is effective, but it will 
 lose its strength unless very tightly corked with 
 glass or rubber. The fumes escaping around the 
 stopper will rust metals and " eat "fabrics even 
 at some distance. 
 
 Whenever this acid is used there should be 
 thorough rinsing of the fabric in water, prefer- 
 ably warm, and then neutralization in ammonia. 
 
 Bleachers. \\\ m Bleachers. These are sometimes used 
 
 to remove color from colored fabrics, but more 
 often to remove the yellow or brownish discol- 
 oration from fabrics which are naturally yellow 
 or which were originally white. 
 
 Sometimes the action is the result of adding 
 oxygen to the coloring matter; sometimes it 
 takes oxygen away. In both cases colorless com- 
 pounds are left, and in both cases moisture is 
 necessary. 
 
 Sunshine. The best bleacher is sunshine with moisture. 
 
 The action here is very complex, resulting in the 
 formation of ozone, but there is never any harm 
 to the fabric. The best way of using " Nature's 
 bleach" is to spread the fabrics on the grass, wet 
 them frequently with soapy, or better with borax 
 or ammonia water, leave out over night for the 
 
COOKING AND CLEANING. 155 
 
 dew to form on them, turn occasionally that all 
 parts may be acted upon, and continue this until 
 the desired whiteness is reached. 
 
 In "dog days," however, the fabrics must be 
 carefully watched, else they will mildew. 
 
 The best time for grass bleaching is during the 
 long days of June. 
 
 If grass is not available, any other means by 
 which the wet cloth can be exposed to direct sun- 
 shine will answer. The wet, yellow handkerchief 
 or lace may be kept by the sunny window until 
 bleached. 
 
 Cloth laid on the snow bleaches fairly well. 
 When clothes freeze the moisture is retained so 
 much longer that even in the short, sunny days 
 of winter considerable bleaching may be done. 
 
 All bleaching with chemicals is attended with 
 danger to the fibre ; but it is so much more rapid 
 and so convenient a method that not only its 
 dangers should be understood, but also how to 
 obviate them. 
 
 When the chemical has completed its action 
 with the coloring matter, it attacks the fibre 
 unless quickly removed. 
 
 i. Hydrogen peroxide, H 0„, may be pur- Hydrogen 
 
 i i r i« ^,i • Peroxide. 
 
 chased as a live per cent liquid. This is a power- 
 ful oxidizing agent. It loses the extra atom of 
 oxygen readily and should be kept in a dark place, 
 preferably closed with a rubber stopper, 
 
156 
 
 THE CHEMISTRY OF 
 
 Sulphur 
 Dioxide. 
 
 Chloride of 
 Lime. 
 
 It may be safely used with all fibres, being 
 especially good for wool. The bleaching action 
 is permanent. 
 
 It is an excellent disinfectant for wounds, sore 
 throat, etc. 
 
 2. Sulphur dioxide, S0 2 , is made by burning 
 sulphur in the air. With moisture the dioxide 
 forms sulphurous acid, H 2 SO s . 
 
 This is effective on moist silk, wool, straw and 
 paper. The fumes should not be breathed. The 
 country housewife attaches the wet, yellowed 
 straw hat to the bottom of a barrel, which is 
 then inverted over a small kettle of coals and 
 sulphur. 
 
 This is much less destructive to the fibre than 
 chloride of lime, but the color often returns. 
 The fumes from a burning match held under 
 the wet hand will remove the purple stains left 
 from black kid gloves. They are also very effect- 
 ive for blueberry and blackberry stains. 
 
 The common sulphur candle is a convenient 
 means of obtaining sulphur fumes. They may 
 be readily concentrated by inverting over the 
 candle a paper, cardboard or other funnel. 
 
 3. Calcium hypochlorite is called bleaching 
 powder and "chloride of lime." Its composition 
 is not definitely known, but approximately is 
 given as CaOCL. A similar compound is some- 
 
COOKING AND CLEANING. m 157 
 
 times called "chlorinated lime." (Chlorinated 
 soda is also on the market.) 
 
 When treated with acids this gives off chlorine, 
 freely. The carbon dioxide in the air liberates 
 it slowly, so that its very presence in the house 
 (or its use as a deodorizer or disinfectant) is a 
 prolific source of rust and deterioration of cotton 
 and other fabrics. 
 
 Whether used for general bleaching or in the 
 removal of stains, thorough rinsing and neutral- 
 ization in ammonia water must follow, else the 
 fabric will suffer. 
 
 4. Javelle water, really sodium hypochlorite, J avelle Water - 
 is a compound made by mixing "chloride of 
 
 lime" and sodium carbonate. It is excellent 
 for the treatment of old or obstinate stains as 
 well as a general bleach. Ammonia or sodium 
 hyposulphite should be used afterwards. 
 
 5. Sodium thio sulphite — called also hyposul- Hyposulphite, 
 phite, Na 2 S 2 3 + 5H 2 0, the "hypo" of the pho- 
 tographer — is especially effective in removing 
 
 the marks of indelible ink containing silver 
 nitrate. 
 
 6. Borax (see page 149). Borax - 
 IV. Solvents. For grease there are naphtha, Solvents - 
 
 benzine, gasoline, ether, chloroform, extremely 
 volatile ; kerosene, turpentine, carbon tetrachlo- 
 ride, coal tar benzine (C H 6 ), alcohol less volatile. 
 
158 . THE CHEMISTRY OF 
 
 The vapors of all these substances are heav- 
 ier than air, therefore sink. They should be used 
 out-of-doors or by an open window, and never 
 where there is any fire. There should be a cur- 
 rent of air near the floor to ensure quick removal 
 of the vapor. 
 
 Turpentine is a resinous oil which serves as a 
 solvent for paint, grease, tar and wax. Mixed 
 with oil, preferably boiled linseed, it makes the 
 best general furniture polish. It cleans more 
 readily than kerosene, but does not give so good 
 a polish. It removes ink stains from polished 
 woods, from which it usually removes the gloss 
 and should be followed by oil and hard rubbing. 
 It will remove some inks from colored fabrics. 
 In the laundry it tends to whiten clothes. When 
 fresh it is clear and has little odor. When ex- 
 posed to the air it takes up oxygen, darkens and 
 thickens. This should not be used on fabrics, as 
 it will itself stain. 
 
 The vapors of chloroform and carbon tetra- 
 chloride are non-inflammable and non-explo- 
 sive. These, like ether, should be used where 
 there is a good draft, as they produce anaesthesia. 
 Chloroform is least likely to injure colors, 
 although ether is usually safe. 
 Oils. V. Oils. The most common vegetable oils 
 
 are raw and boiled linseed, sweet or olive and 
 
COOKING AND CLEANING. 159 
 
 cottonseed. They are all good for polishing 
 woodwork and metals, for softening and bright- 
 ening leather (particularly olive oil), to imbed 
 frictional materials, as emery for iron, rotten- 
 stone or tripoli for brass and copper; to soften 
 pitch, tar, etc. 
 
 Mineral oils are kerosene, an excellent cleaner, 
 a good polisher, a solvent of vaseline, an insecti- 
 cide ; and paraffin oil — less odorous than kero- 
 sene but a little more expensive. Mixed with 
 turpentine in equal parts it makes an excellent 
 furniture polish for very light-colored woods 
 when the linseed oil, which is usually used, might 
 darken them too much ; coal tar benzine, C 6 H 6 , 
 is excellent for removing grease, pitch and resin. 
 
 VI. "Alcohols." Ethyl alcohol, C 2 H 5 OH, A1 «> hols - 
 "grain alcohol," is valuable for removing stains. 
 "Wood alcohol," CH 3 OH, is less effective and is 
 poisonous when taken internally. It should 
 therefore be labeled " Poison." 
 
 Denatured alcohol may or may not be effective 
 for use on fabrics, according to the foreign 
 substances which have been added. 
 
 Alcohol dissolves shellac and turns varnish 
 and wax white. White stains on shellaced wood 
 are removed by gentle tapping with a bit of 
 flannel cloth wet in alcohol. 
 
 VII. Stiffening Agents. Starch is obtained stiffening 
 
 ° ° Agents. 
 
160 THE CHEMISTRY OF 
 
 from many plants, but chiefly for laundry uses 
 from corn, wheat and rice. Potatoes and sago 
 also furnish it. Wheat starch is most satisfac- 
 tory for general purposes. It gives a more flex- 
 ible stiffness and smoother surface than corn 
 starch, 
 starch. Rice starch is excellent for delicate work, as 
 
 fine dress goods and laces. As was shown in the 
 previous pages, uncooked starch is not soluble in 
 water. 
 
 In cold starching the spaces between the 
 threads of the fabrics are filled and the surface 
 coated with the fine powder. The heat of the 
 iron with the moisture brings about the change 
 of condition and great stiffness results. 
 
 It is better for general stiffening purposes to 
 cook starch thoroughly before applying it to 
 the fabric. As this cooking may caramelize a 
 part, making it slightly yellow, a very little blu- 
 ing may be added to counteract it. Thoroughly 
 cooked starch should not stick to a hot iron ; but 
 a little turpentine, wax or paraffin added helps 
 the iron to slip over the surface more readily 
 and adds some gloss. 
 
 A little borax in the starch preserves the stiff- 
 ness of starched articles when they are exposed 
 to dampness," as at the seashore. 
 
 Starched articles should not freeze before 
 ironing. 
 
COOKING AND CLEANING. 161 
 
 Prepared starches are sometimes made soluble 
 by treatment with acids. These frequently affect 
 the color of colored fabrics upon which they are 
 used. 
 
 Some also have borax or other alkali combined 
 with them, and these also change colored fabrics. 
 
 Blues, pinks and greens seem to be most sus- 
 ceptible to these changes. If a blue is turned 
 pinkish it may be well to add a little ammonia or 
 borax to the starch; if pink is turned blue, add 
 a little acid — clear vinegar or lemon juice. Per- 
 haps the safer way is better, i. e., to use only the 
 starch bought in bulk. 
 
 Gum arabic, sugar, glue and gelatine are all other Agents, 
 valuable for stiffening thin, delicate fabrics. 
 
 Black laces, straw hats and ribbons are often 
 stiffened sufficiently by rinsing them in alcohol 
 and water. This slightly dissolves the still 
 remaining stiffening. 
 
 VIII. Bluings. These substances are used to Bluings, 
 counteract or cover by their blue color the yel- 
 lowness which results from imperfect washing or 
 rinsing ; from too much or too strong alkali ; 
 from iron in the water ; or from the action of the 
 air or the absence of light, as when fabrics are 
 unused and stored in dark places. Blue and 
 yellow, however, do not make white. The color 
 which results from the use of bluing varies from 
 gray to green or blue when compared with white. 
 
162 THE CHEMISTRY OF 
 
 The bluings act either mechanically by leaving 
 a fine, impalpable powder among the meshes as 
 ultramarine, or by a tint absorbed by the fibre 
 from the blue solution. 
 
 The public laundries use almost exclusively an 
 aniline blue. This may be purchased solid or 
 liquid and is a real dye. It requires an acid 
 medium before it will set, and too many times 
 this acid injures the fabrics. As it is a dye, it is 
 difficult to remove the effects when too much is 
 used. 
 
 A good blued water is excellent for preserving 
 the original color of blue fabrics. It also im- 
 proves the appearance of dull or blue-black 
 goods. 
 Frictionai IX. Frictional Materials. These do not act 
 
 chemically, but are important agents in the proc- 
 esses of cleaning and preservation. They may 
 be combined with soap, oils or other substances 
 into solid or paste-like form. 
 
 The best of the frictional materials are whit- 
 ing, silicon, rouge, rotten-stone, tripoli, emery, 
 pumice and common sand of various degrees of 
 coarseness. Coal ashes, sifted, make an excellent 
 frictional material. 
 
 The commercial, prepared forms are often 
 more convenient for use, but much more expen- 
 sive; and any undesirable, sharp, gritty parti- 
 
 Materials. 
 
COOKING AND CLEANING. 163 
 
 cles, which would scratch or mar the article 
 scoured, might not be detected until the injury 
 occurred. Again the temptation is strong to put 
 into these manufactured materials substances 
 which will "take hold quickly," or "do the work 
 in half the time," and these are apt to be injuri- 
 ous to the articles cleaned. 
 
 X. Absorbent Materials. Pipe clay, Fuller's ^sorbent 
 earth, French chalk, are perhaps the best. It 
 should be remembered that starch, flour, meal, 
 sawdust, blotting paper and similar materials 
 
 have much absorbent power. These extract 
 liquids mechanically and therefore do not affect 
 the fabric. 
 
 XI. Miscellaneous: i. Alum, a crystalline Alum, 
 double salt of potassium and aluminum. It is 
 used for clearing water from suspended organic 
 matter by coagulation, for "fixing" colors and 
 
 for making cotton fabrics less inflammable. 
 
 For the laundry, two ounces of alum to a 
 gallon of water is sufficient. Less than this will 
 set most colors. 
 
 Sugar of lead, lead acetate, fixes colors, 
 but it is a strong poison and its use is not 
 recommended. 
 
 2. Litmus paper is convenient for testing Litmus Paper, 
 solutions, either for acidity or alkalinity. The 
 red paper will give a rough test of free alkali if 
 
164 THE CHEMISTRY OP 
 
 it be moistened and laid on soap ; the blue paper 
 for acid, on bread dough, etc. 
 
 One piece may be used alternately in acid and 
 alkaline solutions an indefinite number of times, 
 salt. 3. Sodium chloride, NaCl, common salt, is 
 
 used as a condiment, an antiseptic ; for friction 
 and absorption; to remove silver sulphide (see 
 p. 112); in the laundry for fixing colors tem- 
 porarily and to aid in removing red wine, blood 
 and iron-rust stains. 
 
 Its action in setting colors is chiefly in decreas- 
 ing the solvent power of the water. 
 
 New goods, liable to fade, should be rinsed in 
 it before being washed with soap. 
 
CHAPTER VI. 
 Antiseptics, Disinfectants, Insecticides 
 
 FUNDAMENTALLY and ordinarily clean- 
 ness depends upon the prevention or re- 
 moval of unclean conditions — both the presence 
 of the living agents and that of the organic 
 matter on which they feed. Rosenau says: 
 "While the old idea that filth and unsanitary 
 conditions breed disease de novo is wrong, it is 
 nevertheless true that these conditions keep 
 the infectious principles alive and favor their 
 propagation." 
 
 When infectious material is present, danger 
 is imminent and safety may require that the 
 living agents be destroyed that they be not 
 spread about. 
 
 If their growth can be prevented, a measure Antisepsis, 
 of safety is attained. This is the condition of 
 antisepsis. It is brought about by producing 
 unfavorable conditions of growth. For this pur- 
 pose positive or negative means may be em- 
 ployed. The addition of sugar in preserves 
 lessens the air and water supply of the ferments ; 
 
Disinfection. 
 
 166 THE CHEMISTRY OF 
 
 salt withdraws moisture; drying by any means, 
 as the admission of sunlight and fresh air — 
 these are all antiseptic measures. Or, substances 
 may be applied which will retard or prevent the 
 growth of the germs. These are called antisep- 
 tics; soap, salt, strong acids, essential oils, 
 smoke, all act in this manner. Weak solutions 
 of substances which when strong will kill the 
 germ usually prevent or retard its action. Boric 
 acid is one of the best of the chemical antiseptics. 
 
 But this is only partial immunity. Safety re- 
 quires that the living agent of infection be killed. 
 This is the office of disinfection. Substances 
 which kill disease germs are called disinfectants. 
 All disinfectants are germicides. Sterilization 
 means the absence of all life, whether by proc- 
 esses of removal or death. This is a much 
 broader term than disinfection. Disinfectants 
 may kill the pathogenic forms, while many harm- 
 less ones remain. Sterilization would affect all. 
 This is seldom necessary. The state of asepsis 
 is equivalent to sterilization. 
 
 An ideal disinfectant will destroy the patho- 
 genic germs without injury to the infected mate- 
 rial. This may be difficult to find, as no one 
 agent is applicable either to all germs or to all 
 materials. Direct sunshine is Nature's best and 
 cheapest disinfectant. It will, however, fade 
 
COOKING AND CLEANING. 167 
 
 color; but this should not be considered where 
 infectious material is liable to be present. It 
 destroys the superficial spores as well as the 
 active forms ; but cannot penetrate opaque ob- 
 jects, and not deeply into solutions. It is most 
 effective, then, on surfaces. 
 
 Dry heat, 300 F., is sufficient to destroy the Dry Heat, 
 common pathogenic germs, but this is far above 
 what can be used, without injury, in most cases. 
 
 Dry heat is not so effective as moist heat. 
 Anything that can be boiled or steamed can be 
 most surely made safe. 
 
 In "Disinfection and Disinfectants," Dr. Ros- 
 enau says, regarding dry heat, boiling and 
 steam : 
 
 "Most materials will bear a temperature of 
 110° C. (about 230 F.) without much injury, 
 but when this temperature is exceeded, signs of 
 damage soon begin to show. Scorching occurs 
 sooner in woolen materials, such as flannels and 
 blankets, than with cotton and linen. The over- 
 drying renders most fabrics very brittle, but this 
 injury may be lessened by allowing the materials 
 which have been subjected to dry heat to remain 
 in the air long enough to regain their natural 
 degree of moisture before manipulating them. 
 
 "The ordinary household cooking oven is as 
 good as any specially contrived apparatus for the 
 disinfection of small objects by dry heat. In the 
 absence of a thermometer it is usual to heat 
 
168 THE CHEMISTRY OF 
 
 the oven to a point slightly below the tempera- 
 ture necessary to brown cotton, and expose the 
 objects no less than one hour. 
 
 "Dry heat fixes many stains, so that they will 
 not wash out." This is especially marked with 
 albuminous materials coagulable by heat, and 
 the method should not be used for the disinfec- 
 tion of fabrics and objects soiled with blood, 
 sputum, excreta or similar substances." 
 
 The objection to such use of the oven lies in 
 the handling of infected articles in the kitchen, 
 the worst place in the house to set free these 
 dangerous plants. 
 
 steam. "Steam is the most valuable disinfecting agent 
 
 we possess. It is reliable, quick, and may be 
 depended upon to penetrate deeply" if the appli- 
 cation is prolonged. "It does more than disin- 
 fect; it sterilizes. Bacteria are killed instantly, 
 spores are killed in a few minutes, and it may 
 therefore be used to destroy the infection of any 
 one of the communicable diseases. . . ." 
 
 "Steam is very apt to shrink woolens and in- 
 jure silk fabrics. It ruins leather, fur, skins of 
 all kinds, also rubber shoes, mackintoshes and 
 similar articles made of impure rubber." 
 
 Boiling. "Boiling is such a commonplace, every-day 
 
 process that it is often neglected in practical dis- 
 infection, despite the fact that it is one of the 
 readiest and most effective methods of destroy- 
 ing infection of all kinds. An exposure to 
 boiling water at ioo° C, continued half an hour, 
 will destroy the living principles of all the 
 
COOKING AND CLEANING. 169 
 
 known infectious diseases, even very resisting 
 spores. . . ." 
 
 "Boiling is particularly applicable to the dis- 
 infection of bedding, body linen, towels and 
 fabrics of many kinds ; to kitchen and tableware ; 
 to cuspidors, urinals and a great variety of ob- 
 jects. Surfaces, such as floors, walls, beds, fur- 
 niture, etc., may be effectively disinfected by 
 mechanically cleansing them with boiling water. 
 The efficacy of boiling water, especially when 
 used under such circumstances, is greatly in- 
 creased by the addition of corrosive sublimate, 
 carbolic acid, or any one of the soluble germi- 
 cidal agents. The addition of lye, borax or a 
 strong alkaline soap greatly increases the pene- 
 trating power of boiling water, when applied to 
 surfaces soiled with organic or oleaginous 
 matters." 
 
 "In using boiling water for the disinfection of 
 bright steel objects or cutting instruments, the 
 addition of one per cent of an alkaline substance 
 (bicarbonate of soda) will prevent rusting and 
 injury to the cutting edge." 
 
 "In the household, small objects, body and bed 
 linen, and other fabrics may be thoroughly disin- 
 fected by streaming steam by placing a large pot 
 or washboiler on the kitchen fire, and arranging 
 broom handles across the top to hold the mate- 
 rials to be disinfected. The whole should be 
 covered with a sheet or cloth to retain the heat, 
 and steamed for an hour or longer, depending 
 upon the degree of penetration required and the 
 energy with which the water boils," 
 
170 
 
 THE CHEMISTRY OF 
 
 Fire. 
 
 Solutions. 
 
 Formalin. 
 
 Here, again, excessive precautions must be 
 taken in handling such materials in the kitchen. 
 
 Fire is by all means the surest disinfectant. 
 Anything which can be burned is reduced to its 
 inorganic elements, and these are not food for 
 the pathogenic germs. 
 
 Whenever any infectious material is liable to 
 be produced, as in all discharges from commu- 
 nicable diseases, an effort should be made to 
 receive it in or upon combustible materials of 
 little value which can be burned immediately. 
 
 Solutions. These must not only be strong 
 enough, but in such quantity that the strength 
 shall not be diluted by the infectious material 
 beyond the effective point. The time of action 
 is also an essential factor. If the microbes are 
 dry it will take a certain time to wet them before 
 the chemical action can take place. Unless the 
 infected material can be immersed in the disin- 
 fectant solution, it is difficult to keep the two in 
 contact long enough to effect safety. Tempera- 
 ture, also, is an important factor in successful 
 disinfection. It is always well to use warm — 
 hot, if possible — solutions and combine their 
 action with mechanical removal, or scrubbing. 
 
 Formalin is a solution of formaldehyde. A 
 very small amount is antiseptic, even i in 25,000 
 or 50,000, while one to four per cent kills in a 
 short time. This method kills spores, also. 
 
COOKING AND CLEANING. 171 
 
 Lime or quicklime, CaO, is an alkaline earth. 
 It is very caustic and therefore useful in destroy- 
 ing organic matter. 
 
 Calcium hydrate, slaked lime, Ca(OH) 2 , is siakedLime. 
 made by adding one part of water to two parts 
 of quicklime. 
 
 For a disinfectant, freshly slaked lime should 
 be used. When the slaked lime is exposed to 
 the air it readily takes up carbon dioxide and is 
 converted into calcium carbonate, which has no 
 particular disinfecting power. 
 
 Whitewash is slaked lime mixed with water, whitewash. 
 It is an excellent disinfectant for surfaces, and is 
 a form of milk of lime, which is slaked lime 
 with about four times its volume of water. Milk 
 of lime must be prepared from freshly slaked 
 lime and should be thoroughly stirred to prevent 
 the insoluble hydrate from settling. At least 
 two hours' contact should be allowed when this 
 is used for disinfecting excreta, and it should be 
 thoroughly incorporated. Milk of lime as used 
 for the disinfection of excreta in the United 
 States Army posts is made from one part, by 
 weight, of freshly slaked lime to eight parts of 
 water. The excreta should stand in this at least 
 two hours before disposal. 
 
 Ferrous sulphate, green vitriol, as copperas, Copperas. 
 FeS0 4 , so commonly depended upon as a disin- 
 
172 THE CHEMISTRY OF 
 
 fectant, has been found to be practically useless. 
 It is a fairly good deodorant, 
 carbolic Add. Carbolic acid, C 6 H 5 OH, phenol, does not co- 
 
 agulate albuminous matter so readily as corro- 
 sive sublimate. It cannot be depended upon to 
 kill spores, but is fairly good for the vegetative 
 stage. In the strengths necessary for disinfec- 
 tion it is not destructive to fabrics, colors, metals 
 or wood. 
 
 It should be used in a 1-20 solution. If much 
 is required it will be cheaper to buy the con- 
 centrated, which is a ninety-five per cent solution, 
 and reduce it to the desired strength. Four 
 ounces of this strength with five pints of boiling 
 water will give the required 1-20 solution. The 
 strong acid is very corrosive and must not touch 
 the skin. ♦ 
 
 Quoting again from Dr. Rosenau's book, we 
 find that "in general practice carbolic acid is 
 used in from three to five per cent solutions, and 
 an exposure of no less than half an hour. Cloth- 
 ing and fabrics require deep penetration, and are 
 usually left in the solution one hour." 
 c-esois. Crcsols are a class of substances obtained from 
 
 coal tar, found as impurities in commercial car- 
 bolic acid or phenol. 
 
 Their value is variable. Creolin is a common 
 and cheap member of this class. It contains 
 
COOKING AND CLEANING. 173 
 
 about ten per cent of cresols and a small amount 
 of phenol held in solution by soap. It is at least 
 equal to and usually superior to the phenol. A 
 one per cent solution is effective for ordinary 
 purposes. 
 
 Potassium permanganate, KM 4 4 , the cham- p°JJJ s j, u ™ t 
 aeleon minerale, as it was called by the early 
 chemists, is a powerful oxidizing agent and a 
 strong germicide under limited conditions. It is 
 readily reduced and rendered inert by organic 
 matter. 
 
 Swampy water may be purified by it if enough 
 is added to allow the faint pink color to remain 
 when the brown precipitate which has enmeshed 
 the bacteria is settled or filtered off. 
 
 There is a possible danger of internal irrita- 
 tion when this chemical is used continuously in 
 potable waters. 
 
 Mercuric chloride, HptCL, corrosive sublimate. Corrosive 
 
 . . , t « •« i i • i Sublimate. 
 
 is a potent germicide. It kills both active and 
 spore forms. It is a virulent poison, corrodes 
 metals, and unless used with salt it coagulates 
 albuminous matter. For disinfection of excreta, 
 therefore, salt must be added. It dissolves with 
 some difficulty in three parts of boiling water 
 or sixteen parts cold water. It should, there- 
 fore, be powdered before the water is added, 
 care being taken not to inhale the dust. The 
 
174 THE CHEMISTRY OF 
 
 solution is colorless and odorless, and has been 
 mistaken for water when not properly labeled. 
 The commercial tablets contain salt and are often 
 colored blue. The solution may be slightly col- 
 ored with indigo, or any of the aniline dyes, and 
 this should be done always as a precautionary 
 measure. 
 
 The i-iooo strength is sufficient to kill non- 
 spore-bearing species if allowed to act for half 
 an hour. For spores the 1-500 solution and an 
 hour's exposure is required. 
 
 A gaseous disinfectant is ideal if it can be 
 made to penetrate thick fabrics when they are 
 slightly moist, so that the gas may be absorbed 
 and brought into intimate contact. This is diffi- 
 cult to accomplish for the housewife, because 
 the gas must be delivered under pressure. 
 Formaldehyde. At present, formaldehyde seems to approach 
 this ideal most nearly. It is non-poisonous, does 
 not injure fabrics, metals or mineral surfaces. 
 In disinfecting with formaldehyde, temperature 
 plays an important part. The gas is not effective 
 under 50 F. and increases in power with the 
 higher temperatures. Moisture, also, is neces- 
 sary for its effectiveness. A basin of water, kept 
 boiling, may be used to furnish the moisture. 
 The gas does not penetrate thick masses or fab- 
 rics readily, unless it is delivered under pressure, 
 
COOKING AND CLEANING. 175 
 
 therefore such articles should be spread out as 
 thin as possible, and more time should be allowed 
 than for ordinary disinfection. 
 
 When the disinfection of a room with a gas 
 is completed, the doors and windows should be 
 opened as quickly as possible. If a person enters 
 the room to do this, he should cover the eyes, 
 nose and mouth with a moist cloth to prevent 
 the • irritation caused by the gas. Ammonia 
 sprinkled about the room will neutralize the gas, 
 but forms with it a substance having a very 
 persistent odor. 
 
 Soaps have an antiseptic action, and it is Soa P s - 
 asserted by many that pure white castile soap 
 is germicidal. 
 
 According to Dr. Rosenau: "Medicated soaps 
 are for the most part a snare and a delusion so 
 far as any increased germicidal action is con- 
 cerned ; in fact, the addition of carbolic acid, bi- 
 chloride of mercury, and other substances which 
 have the property of combining with the soap, 
 seems actually to diminish the disinfecting value 
 of that substance. As a rule, a very small quan- 
 tity of the disinfecting substance is added to the 
 soap, and when it is called to mind what an ex- 
 ceedingly small quantity of soap is necessary for 
 the ordinary washing of the skin, and the further 
 dilution of this small amount by the water used, 
 
176 THE CHEMISTRY OF 
 
 it is easy to understand that medicated soaps, as 
 ordinarily applied, cannot have an energetic 
 disinfecting action." 
 
 The value of soap is in its superficial cleansing, 
 the removal of objectionable matter. 
 Deodorants. Another class of substances which are often 
 
 used, and sometimes with danger, are those 
 which destroy odors. These are substances 
 which combine with the decomposing matter, 
 forming new and odorless compounds. Charcoal 
 is such a substance. 
 
 This is the office of a true deodorant. The 
 name is sometimes applied to other substances 
 which produce no chemical or physical changes, 
 but simply cover up the odor given ofT by the 
 decaying matter by one stronger or more 
 agreeable. 
 
 Deodorants simply destroy smells ; disinfect- 
 ants and germicides destroy germs. Most disin- 
 fectants are at the same time deodorants. 
 
 The question is constantly asked, "What disin- 
 fectants can I use that are common and cheap?" 
 
 The last published report of the American 
 Public Health Association speaks authoritatively 
 upon this question, and from this the following 
 quotation may be taken as a summary of the 
 present status of the subject: 
 ummonule/™ "The weight of opinion seems to be that alco- 
 
COOKING AND CLEANING. 177 
 
 hoi from 40-60% is quite a strong germicide, 
 but that lower and higher percentages are much 
 weaker in their action. Two observers class it 
 about midway between sublimate and carbolic 
 acid in strength. 
 
 "Whether it acts as a direct poison or indi- 
 rectly through the water present is not yet estab- 
 lished, but the weight of opinion seems to be that 
 it acts directly." 
 
 The vapor from boiling alcohol solutions 
 is more effective as a disinfectant than the 
 solutions. 
 
 "There are a few common disinfectants the 
 efficiency of which has been firmly established, 
 namely, boiling water, hot soda solution (about 
 10% solution of sal-soda in water), milk of lime 
 (pieces of lime slacked to a milk), corrosive sub- 
 limate and formaldehyde. I would add some of 
 the cresol preparations except that they are pat- 
 ented and hence not cheap enough for common 
 use in the United States. I leave out carbolic 
 acid because of its poisonous properties, and 
 chloride of lime because of its uncertain compo- 
 sition. Nothing better or more effective is 
 needed to disinfect feces and such matters than 
 milk of lime ; nothing to disinfect clothes than 
 steam, hot water or hot soda solution ; for quick 
 sterilization of the hands a 1-1000 sublimate solu- 
 tion is the best ; and as a room disinfectant, 
 formaldehyde properly used still holds the first 
 place. . . ." 
 
 Some insects are known to carry infectious Insects - 
 
178 THE CHEMISTRY OF 
 
 matter, and it is easy to understand how any 
 animal may convey such material from one place 
 to another and possibly to man. They certainly 
 do carry on their bodies minute infectious parti- 
 cles gathered from moist substances, as excreta, 
 pus, sputum, over which they have crawled. 
 They carry also the agents of decomposition 
 from decaying food, depositing them upon other 
 food and thus starting decomposition in it. 
 
 In some cases the infectious germ is intro- 
 duced into human beings from the body of the 
 insect as it stings or bites. This is the case with 
 the flea and the mosquito, which carry malarial 
 and yellow fever germs. 
 
 The flies, fleas, ants, etc., deposit the infectious 
 material on the skin with their excrement, and in 
 other ways. The virulent infection is rubbed 
 into the little wounds or scratched into the skin 
 as a result of the irritation caused by the bites, 
 thereby setting up the disease. 
 
 Therefore all insects may be looked upon with 
 suspicion, while mosquitoes, flies, roaches, bed- 
 bugs and fleas should receive no quarter in the 
 clean and healthful house, 
 insecticides. Most germicides are insecticides. Yet formal- 
 
 dehyde is a notable exception. It has slight 
 effect upon insect life. 
 
 Sulphur dioxide. This gas holds first place 
 
COOKING AND CLEANING. 17d 
 
 for killing insects and vermin. As an insecticide 
 it can be used dry, while as a germicide, as has 
 been said, moisture is necessary. 
 
 Bisulphide of carbon, CS 2 , and hydrocyanic 
 acid gas, HCN, are both powerful insecticides. 
 They are also deadly poisons to all animal life. 
 They should therefore never be used except by 
 experts. The United States Government has 
 published some valuable bulletins upon the use 
 of these substances. 
 
 Kerosene kills bedbugs and their eggs. Ap- 
 plied to the surface of water at the rate of an 
 ounce to fifteen square feet of surface it destroys 
 mosquitoes and their larvae. It is therefore use- 
 ful in covering all moist matter in which they 
 may breed. 
 
 "Insect powder" or " Persian or Dalmatian in- 
 sect powder," is usually the powdered flowers of 
 two species of chrysanthemum, C. roseum and 
 C. carneum. They are also sold under the names 
 of pyrethrum and buhack. The powder acts 
 mostly by filling the breathing holes, causing 
 suffocation. It will kill, but too often only stu- 
 pefies the insects, which should then be gathered 
 and burned. Water bugs and fleas are driven 
 from their lairs to be caught while stupefied. 
 
 The powder may be burned, and in this form 
 is quite effectual for mosquitoes. 
 
180 THE CHEMISTRY OF 
 
 The poisonous fly papers kill the insects, but 
 they fall everywhere about the house, and the 
 presence of these arsenical compounds is dan- 
 gerous wherever there are children. 
 
 The sticky fly papers do not kill but hold the 
 insects, and they die from exhaustion, 
 
BOOKS OF REFERENCE. 
 
 Approved Methods for Home Laundering. M. B. Vail. 
 
 Art and Practice of Laundry Work. M. C. Rankin. 
 
 Bacteria, Yeasts and Molds in the Home. H. W. Conn. 
 
 Care of a House. T. M. Clark. 
 
 Chemistry of the Household. M. E. Dodd. 
 
 Chemistry of Plant and Animal Life. Harry Snyder. 
 
 Clean Milk. S. D. Belcher. 
 
 Disinfection and Disinfectants. M. J. Rosenau. 
 
 Domestic Economy in Theory and Practice. Bidder and 
 
 Baddely. 
 Drinking Water and Ice Supplies. T. M. Prudden. 
 Dust and Its Dangers. T. M. Prudden. 
 Elementary Laundry Work. Calder and Mann. 
 Expert Cleaner. H. J. Seaman. 
 Garment Dyeing and Cleaning. G. H. Hurst. 
 Handbook of Domestic Science and Household Arts. 
 
 L. L. W. Wilson. 
 Handbook on Sanitation. G. M. Price. 
 Home Furnishing. A. M. Kellogg. 
 Home Sanitation. Richards and Talbot. 
 House and Home. M. E. Carter. 
 House that Jill Built. E. C. Gardner. 
 Household Bacteriology. S. M. Elliott. 
 Household Economics. Helen Campbell. 
 Household Hygiene. S. M. Elliott. 
 How to Drain a House. G. E. Waring, Jr. 
 Hygiene and Public Health. L. C. Parkes, 
 
182 BOOKS OF REFERENCE. 
 
 Laboratory Notes in Household Chemistry. Vulte and 
 
 Goodell. 
 Laundry Manual. Balderston and Limerick. 
 Laundry Work. J. L. Sheppard. 
 Outlines of Rural Hygiene. H. B. Bashore. 
 Principles of Sanitary Science and Public Health. W. T. 
 
 Sedgwick. 
 Sanitary and Applied Chemistry. E. H. S. Bailey. 
 Sanitation of a Country House. H. B. Bashore. 
 School Sanitation and Decoration. Burrage and Bailey. 
 Story of the Bacteria. T. M. Prudden. 
 Story of Germ Life. H. W. Conn. 
 Story of the Living Machine. H. W. Conn. 
 Text-Book of Physiological Chemistry. Hammersten. 
 Text-Book of Physiology. William Howell. 
 
INDEX. 
 
 Absorbents of grease, 100, 101, 163 
 Acids, 41, 151 
 
 Acetic, 38, 152 
 
 Butyric, 35 
 
 Carbolic, 172 
 
 Citric, 152 
 
 for iron stains, 132 
 
 Hydrochloric or Muriatic, 17, 41, 
 132, 153 
 
 Lactic, 152 
 
 Oxalic, 116, 153 
 
 Stearic, 43 
 
 Tannic, 50 
 
 Tartaric, 153 
 Air, as food, 67 
 
 not the agent of change, 73 
 
 pollution of, 84 
 
 pure, 83 
 
 a substance, 85 
 Albumin, 49 
 Albuminoids, 50 
 Alcohol, 30, 36, 159 
 Alcohol, as solvent, 102, 110, 157 
 Alkalies, caustic, 89, 111, 146 
 
 volatile, 89 
 Alkali metals, 88 
 Alum, 163 
 Aluminum, 117 
 Ammonia, 89, 150 
 
 uses of, 73, 93, 102, 125, 139, 150 
 Ammonium, 88, 89 
 Animal body, a living machine, 47 
 
 repair of, 48 
 Antisepsis, 165 
 Art of cooking, 56, 62 
 Atoms, 14 
 Atomic weight, 14, 16 
 
 of hydrogen, 14 
 
 Bacteria, 36, 39, 74, 76, 77, 81 
 
 action of in disease, 80 
 
 as flavor producers, 62 
 
 food of, 81 
 
 spores of, 75 
 Bacteriology of bread-making, 36 
 Baking powder, 22, 23 
 
 Beans, 52, 64 
 
 Beer, 29 
 
 Benzine, 98, 102, 157 
 
 Biscuits, 39 
 
 Bleachers, 154 
 
 Bleaching, 134, 135 
 
 Bleaching powder, 135, 156 
 
 Blinds, 82 
 
 Blood stains, 106, 129 
 
 Blotting paper for ink, 108 
 
 Bluing, 133, 134, 161 
 
 Boiling, 168 
 
 Books for reference, 181 
 
 Borax, 125, 128, 137, 139, 149 
 
 Brass, 116 
 
 Bread-making, chemical reactions in, 
 
 29, 30, 36 
 Bread, as food, 33 
 
 crust, 39 
 
 fermented, 36 
 
 flavor in, 39 4 
 
 homemade, 37 
 
 ideal, 34 
 
 leavened, 35 
 
 object of baking, 38 
 
 reason for kneading, 37 
 
 stale, 39 
 
 temperature of baking, 37, 38, 39, 54 
 of fermentation, 37 
 Butter, 43 
 Butyric acid, 35 
 
 Caesium, 88 
 
 Calcium hypochlorite, 128, 156 
 Calories, 47 
 Calorimeter, 19 
 Cane sugar, 28,29 
 Carbohydrates, 26, 44, 63 
 Carbolic acid, 172 
 Carbon bisulphide of, 179 
 Carbon dioxide (carbonic acid gas), 
 17, 18, 19,25,30,36,37 
 method of obtaining, 40 
 Carbon tetrachloride, 157 
 Casein, 52 
 Caustic alkalies, 89, 147, 148 
 
184 
 
 INDEX. 
 
 Cayenne pepper, 59 
 Cellulose, 27 
 
 Cheese cloth for cleaning, 93 
 Chemical arithmetic, 17 
 Chemical change, 7 
 
 produces heat, 25 
 Chemical elements, 12, 16 
 Chemical equations, 17 
 Chemical experiments in the home, 145 
 Chemical laws, 13, 14, 15 
 Chemical reactions, 17, 25 
 
 in bread and beer making, 36 
 Chemical symbols, 16 
 Chemicals for household use, 145 
 Chloride of lime, 126, 127, 128, 129, 
 
 156, 177 
 Chloroform, 102,157,158 
 Cleaning of brass, 116 
 
 fabrics, 97, 98 
 
 glass, 96 
 
 paint, 93 
 
 powders, 113 
 
 problems of, 90 
 
 processes of, 88, 90 
 
 silver, 111, 116' 
 
 wood, 90, 91,92, 93 
 Cleanness, ideal and sanitary, 142 
 
 personal, 143 
 
 philosophy of, 82, 85 
 
 public, 144 
 
 of schoolhouses, 144 
 Cocoa and coffee stains, 127, 128 
 Collagen, 50 
 
 Colors, setting of, 140, 146 
 Combining weights, 14 
 Combustion of food, 25, 26 
 
 products of, 84 
 Compounds, 13 
 Condiments, 56, 58, 59 
 Consumption, 83 
 Conversion of starch, 28, 30 
 Cooking, American, 58 
 
 art of, 56, 57, 62 
 
 chemistry of, 58 
 
 discretion in, 62 
 
 economy in, 60 
 
 effect of, 54 
 
 fats, 46 
 
 nitrogenous food, 50, 53 
 
 object of, 53 
 
 starch, 32 
 
 vegetables, 60 
 Copper, 115, 116 
 Copperas, 171 
 Corrosive sublimate, 173 
 Cottonseed oil. 43 
 
 Cream of tartar, 23, 41, 42 
 Creolin, 192 
 Cresols, 192 
 
 Decomposition, 64 
 
 Definite proportions, law of, 14 
 
 Deodorants, 176 
 
 Development of flavor, 56 
 
 Dextrose, 29 
 
 Diastase, 29 
 
 Diet, 63, 65 
 
 Diet, fat in, 45 
 
 Dietaries, 68, 69 
 
 Digestion, 28, 61,63, 66 
 
 of fats, 44 
 
 is solution, 28 
 Dirt, definition of, 78 
 
 prevention of, 98 
 Disease, cause of, 80 
 
 prevention of, 79 
 Dish cloths and towels, 140 
 Disinfectants, 166, 176 
 Disinfection, 166 
 Dry heat, 167 
 Dust, 71,72,73,75,87,88 
 
 in air, 72, 76 
 
 composed of, 77 
 
 on fabrics, 97 ,98 
 
 germs, 80 
 
 meteoric, 73 
 
 spots, 103 
 
 on wood, 92 
 
 Economy in cooking, 60 
 
 of mixed diet, 65 
 Effect of condiments, 58 
 
 of cooking, 54 
 Eggs, 51 
 
 Elements, chemical, 12, 16 
 Emery, 162 
 Energy, mechanical unit of, 47 
 
 sources of, 44 
 Ether, 102, 157, 158 
 Expansion of gases, 9 
 
 of water, 40 
 
 Fabrics, 97, 98 
 Fat, digestion of, 44 
 
 in diet, 44 
 
 effect of high temperature on, 46 
 Fats, 24, 43, 45, 55, 88 
 Fermentation, 35, 39 
 Finish of woods, 90 
 Fire, 170 
 
 Flavor, 46, 56, 57, 58, 60 
 Flour, use of, in bread, 39 
 
INDEX. 
 
 185 
 
 Food, office of, 24,69 
 water and air as, 68 
 Formaldehyde, 174 
 Formalin, 170 
 French chalk, 163 
 Frictional materials, 162 
 Fruit stains, 126, 127 
 Fuel in body, 47 
 Fuller's earth, 163 
 Fungi, 74 
 
 Gases, 8 
 
 Gasoline, 157 
 
 Germs, 74, 80, 81 
 
 Glass, 96 
 
 Glucose, 29 
 
 Gluten, 52 
 
 Grass stains, 129 
 
 Grease, 87, 88, 100, 101, 102, 104, 135 
 
 solvents for, 91, 157 
 
 on wood , 103 
 Growth, nitrogenous food required 
 
 for, 48 
 Gums, 24 
 
 Hard water, 119, 120 
 Heat, dry, 167 
 
 produced by chemical change, 24 
 
 source of in animals, 25 
 Hydrochloric acid, 41, 153 
 Hydrogen, 14, 27, 44 
 Hydrogen peroxide, 155 
 Hyposulphite, 157 
 
 Ideal bread, 34 
 Indigo, 133 
 
 Inflammable substances, 98 
 Ink indelible, 109 
 
 stains, 107, 108, 131 
 Inoculation, 82 
 Insect powder, 179 
 Insecticides, 178 
 
 Iron rust, removal of, 117, 131, 132, 
 146 
 
 Javelle water, 126, 127, 128, 129, 130, 
 
 157 
 Jewelry, 115 
 
 Kerosene , 91 , 92, 96, 111 , 116, 117, 131 , 
 
 141, 157, 179 
 Kitchen utensils, 117 
 
 Lard, 43 
 Laundry, 118-142 
 
 Law of definite proportions, 14 
 
 multiple proportions, 15 
 Leather, 94 
 Leaven, 35 
 Legumin, 52 
 Lentils, 65 
 Levulose,29 
 Lime, slaked, 171 
 Lithium, 88, 89 
 Litmus paper, 163 
 
 Marble, 95, 109 
 Matter, changes in, 5 
 
 definition of, 5 
 
 forms of, 8 
 Medicine stains, 127 
 Mercuric chloride, 173 
 Metals, 95, 111,116 
 Mildew, 130 
 Milk stains, 129 
 Mixed diet, 65 
 Molds, 74, 77, 79 
 Molecular weight, 11 
 Molecules, 14 
 Mucous stains, 129 
 Multiple proportions, law of, 15 
 Muriatic acid, 153 
 
 Naphtha, 157 
 Nature's scavengers, 78 
 Nickel, 117 
 Nitrogen, 48 
 
 Nitrogenous food, 47, 49, 68 
 cooking of, 50, 55 
 
 Oils, 43, 45, 88,92,158 
 Oil finish, 91 
 Oil stains, 130 
 Olive oil, 44, 45 
 Oxalic acid, 147 
 Ox-gall, 103, 151 
 Oxygen, 15, 26, 43 
 Oysters, 51 
 
 Paint, 93, 104 
 Paper, 94 
 Pastry, 54 
 
 Pathogenic germs, 81 
 Pearlash,149 
 Pepsin, 64 
 Peptones, 64 
 Physical change, 7 
 Pipe clay, 163 
 Pitch, 105 
 
 Plated silverware, 112 
 cyanide, 113 
 
186 
 
 INDEX. 
 
 Plumbing, care of, 141 
 
 Porcelain, 96, 110 
 
 Potash, 103, 122, 123, 147 
 
 Potassium, 88 
 
 Potassium hydroxide, 147 
 
 Potassium permanganate, 173 
 
 Preparation for food, of starch, sugar 
 and fat, 24 
 
 Prevention, 80, 98 
 
 Products of decomposition, 64 
 
 Proportion of nitrogenous food re- 
 quired, 68 
 
 Pumice, 95, 162 
 
 Rations, 69 
 
 Removal of dust, spots and stains, 87 
 
 Restoring color, 97 
 
 Rouge, 162 
 
 Rotten-stone, 162 
 
 Rubidium, 88 
 
 Rust of iron, 117 
 
 Saliva, 63 
 Sal-soda, 148 
 Salt, 17,41,42 
 Saturation, 9 
 
 Schoolhouse sanitation, 143 
 Seasonable diet, 65 
 Serving, 62 
 
 Shellac, dissolved by alcohol, 111 
 Silicon , 162 
 
 Silver, cleaning of, 111, 113, 114, 115 
 Silver nitrate, 157 
 Silver polish, 113, 114 
 Silverware, 112, 115 
 Soap, 89, 120, 122, 124, 137, 139, 151, 
 175 
 
 bark, 121 
 
 berry tree, 121 
 Soda, 42, 122, 124,148,149 
 Soda ash, 17, 123, 124, 148 
 Sodium, 87 
 
 Sodium carbonate, 148 
 Sodium chloride, 17, 164 
 Sodium hydroxide, 148 
 Sodium thiosulphite, 157 
 Soft water, 119, 120 
 Solution, 9, 28, 50 
 Solutions, disinfecting, 170 
 Solvents, 10, 78, 91, 101, 102, 106, 157 
 
 Source of energy, 44 
 
 Spores, 75 
 
 Spots, 100, 118 
 
 Stains, 100, 106, 118, 126, 127, 128 
 
 Starch, 24, 27, 28, 29, 30, 31, 160 
 
 cooking of, 32, 55, 61, 160 
 Steam, 168 
 Stearic acid, 43 
 Stiffening agents, 159, 160 
 Stimulants, 60 
 Stoves, care of, 117 
 Suet, 43 
 Sugar, 24, 27, 29 
 
 cane, 28 
 
 fruit, 28 
 
 of lead, 163 
 
 milk, 27, 28 
 Sulphur dioxide, 156, 178 
 Sunlight, 82, 83, 84, 85, 154, 166 
 Swelling, 10 
 Symbols, 16 
 Syrups, 10 
 
 Tables, 16, 23 
 
 Tannin, 128 
 
 Tarnish, 100, 101 
 
 Tea stains, 127, 128 
 
 Temperature, 26, 46, 49, 52, 53 
 
 Tripoli, 162 
 
 Turpentine, 91, 102, 103, 126, 158 
 
 Ultramarine, 133, 134, 162 
 Utensils, kitchen, 117 
 
 Varnish, 91, 105 
 Vegetables, 60 
 
 Wall paper, 94 
 
 Washing soda, 124, 125, 148 
 
 Water, 118, 119, 120 
 
 as food, 67 
 
 hard and soft, 119, 120 
 Wax, 91, 105 
 Whiting, 114, 162 
 Wine stains, 121 
 Whitewash, 171 
 Wood finish, 90,91,92 
 Woolens, washing of, 139 
 
 Yeast, 33, 35, 36, 37, 38, 74, 78 
 

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