A ► R. ^ • "£ o. v * r * °* c V * r * °* .0 / ISM*- v^ *s$Mwi° o V V >^ o°"«* ^C ( -ST °^ «, s * * ' ■?- <5> O H <(> <$> * o N o c 1 * -»** ■> i* v«* '/, s * v <* *: o * o 4 1 ^ <* > ^ • * " c\ a? W ^o* :« J?-^ 4 O A* ... V '^ ^°...-,. < rf»- ' N o THE CHEMISTRY OF COOKING AND CLEANING A MANUAL FOR HOUSEKEEPERS (5 BY ELLEN H. RICHARDS AND S. MARIA ELLIOTT Second EdjT'GN Rtvised and Rewritten. BOSTON HOME SCIENCE PUBLISHING CO. 1897 <^ 0,\ \ JVl atter. of change. Experience teaches that matter exists in three different forms — solids, liquids and gases. 4 THE CHEMISTRY OF It teaches, also, that by the action of outside forces some solids become liquids and some liquids be- come gases. The reverse process, 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 in- stances than are observed in ordinary experience. h r a°n|e C in USmg What force, or forces, cause or can be made to tatter. cause 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. The 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 gas- eous form. Heat, then, is one force which brings about a change of state in material substances. If heat be abstracted from a liquid, the latter may become a solid, as when water becomes ice. Like changes are less readily brought about by pressure, gases becoming liquids; liquids becoming solids. Cold and pressure, acting together, are able to liquefy the air even, and other gases once called per- manent. The forces exerted from without, then, are press- ure, and the addition or subtraction of heat. COOKING AND CLEANING. Experience teaches that solid and liquid matter may be divided into smaller and smaller divisions until the particles are no longer visible under a powerful microscope. The scientist is led by his observations to the belief that matter is made up of infinitesimal particles or atoms and that chem- ical changes take place among these atoms and groups of atoms. They are invisible and inde- structible. Each atom occupies space and has weight. Two or more atoms united make a mole- cule, which also is very far from being visible. It may be composed of two or more atoms of the same substance or many atoms of different sub- stances. In the social world there are individuals, fam- ilies and communities; so in the material world there are atoms, simple molecules and complex groups of molecules. The groups or molecules are always separated from each other by greater or less distances. If the groups are many and the distances between them infinitely small, there is a "solid crowd." There must be some force to widen the distance between the groups and make them free to move among themselves. A layer of fat is a crowded mass of molecules — a solid. Heat drives the molecules apart, increases the dis- tance between them, gives them a chance to move more freely and produces, thus, the liquid condi- Atoms and Molecules. States of Matter. 6 THE CHEMISTRY OF tion. Still further separation, with the breaking up of certain groups causes a freedom of move- ment in any and all directions, giving a gas or gases. If not restrained, these may pass entirely beyond our ken though still existent, for "matter cannot be created or destroyed at will." Different degrees of heat produce varying de- grees of liquefaction. The molecules may be given only a slight freedom of movement, causing a semi-liquid state, as in the melting of solder, of gelatine, and of tar. When the molecules are driven further apart the mass necessarily occupies more space. This is expansion. All matter ex- pands or occupies more space under the action of heat; but in gases, the proportion of expansion is much the greatest, for the molecules have perfect freedom of movement. 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. Into these molecular spaces, molecules of other substances may enter. The molecules of solids, however, do not readily pass between one another in this way. The solids must be changed to liquids, that their molecules may have freedom of movement. This is commonly brought about by solution. The degree of solubility of any substance de- COOKING AND CLEANING. 7 pends largely upon the temperature of the sol- vent. Common salt dissolves nearly as well in cold as in warm water. "Soda" and alum dissolve more readily in warm than in cold, while cream of tartar requires hot water for its complete solu- tion. The amount of solid which water will dissolve saturation, usually increases with the temperature to a certain 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 increased if the solid be first powdered, for a greater area is thus pre- sented to the action of the liquid. It is usually more rapid when the powder is placed upon the surface. Under these conditions each particle, while dissolving is surrounded by a thin envelop of syrup, which becomes heavier and sweeter. The film of syrup is washed away by the solvent liquid, so that a clean surface is continually exposed to be acted upon. Some particles are so light that they will not sink; then the process of solution is very slow. Solution is a valuable agent in bring- ing about chemical action during many processes of cooking and cleaning. Water is a nearly universal solvent. It dissolves Solvents, larger quantities of more substances than any other liquid. Some solids, however, dissolve 8 COOKING AND CLEANING. 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 readily in pure water than in that containing some im- purities. Gold may be dissolved in a warm mix- ture of two strong acids. Many of these metallic solutions which may be formed in cooking uten- sils and water pipes are poisonous, and a knowl- edge of them becomes a matter of great im- portance to all housekeepers. A process of daily occurrence in the household greatly resembles solution. It consists in the taking up of water, which produces an increase of bulk or "swelling," but no true solution. Gela- tine 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. CHAPTER II. Elementary Chemistry. MOST substances with which we deal in ordi- nary 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 substances. Finally a substance is found which cannot be di- vided without losing its identity. The chemical element is that substance out of which nothing essentially different has ever yet been obtained. Pure gold is an element from which nothing Elements. can be taken different from itself, but gold coin contains a little copper or silver or both. The oxy- gen of the air is an element. Air is a mixture of two or more elements. Oxygen and hydrogen, both gaseous elements, unite in certain propor- tions 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 symbols which he uses instead of the names. Usually, the first or the first two letters of the Latin name are taken. 10 THE CHEMISTRY OF These symbols mean much more, however, than time saved, as we shall see. Most of the elements unite with each other. 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 lab- oratory or in the physician's medicine case. A few are so rare as to be considered curiosities. Every housewife should understand something 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 laws. 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. It has been assumed that all compounds are formed by the union of atoms — those smallest homogeneous particles of matter. Each atom has COOKING AND CLEANING. 11 its definite weight, which remains constant. This weight is known in chemistry as "atomic weight." No single atom can be weighed by itself, but it is found that hydrogen is the lightest substance known, so the weight of its atom is called one. All other substances are compared with this unit, i. e., their atoms weigh one, two, three or more times the hydrogen atom. Reckoned in this way the atom of oxygen £ hei £ i( { al weighs sixteen and the carbon atom twelve times as much as the atom of hydrogen. The symbol of an element, then, represents 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 which is sixteen times the weight of the H atom. The number of atoms used is indicated by a small figure placed below and at the right of the symbol. When no figure appears, one atom is understood. In a compound, the number of molecules is desig- nated by a large figure at the left of the formula : H 2 S0 4 means one molecule containing two atoms of hydrogen, one of sulphur, four of oxygen. 4H 2 S0 4 means four molecules containing eight atoms of hydrogen, four of sulphur, sixteen of oxy- gen. A little chemical arithmetic is needed to compute the weight of these molecules. Molecular 12 THE CHEMISTRY OF weight is the sum of the atomic weights of the constituent elements. Our chemical example then stands : Two atoms of H= 2 One atom of S^ 32 Four atoms of O^ 64 One molecule of H 2 S0 4 =: 98 Four molecules of H 2 S0 4 =392 392 what? All weights are referred to the standard H ; so the four molecules weigh 392 times as much as the hydrogen atom. The symbols, then, are the chemist's shorthand alphabet, or his sign language. The non-scientific 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 house- wife, 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 ex- COOKING AND CLEANING. 13 presses, is a great step toward mastering the sci- ence." Having thus prepared the ground and collected Laws oi materials, the foundation may be laid — i. e., the laws of chemical combination. It has been said that the elements unite with each other and ex- change places one with another. In society there are persons whose powers of attraction toward others vary widely. In conversation upon any subject, one person may interest, with ease, one individual; another may hold two interested lis- teners; while a few, with rare gifts, may hold to- gether a group of many. We say the last person has a stronger holding power than the other two. This may serve to illustrate what is known by ex- periment to be a fact among atoms. The chemist finds an atom of one element holding to itself one atom of a different element; another, holding two; while a third may hold three or more. Chlorine will hold to itself only one atom of H, making HC1, muriatic acid; but O holds two — H 2 — water; N holds three — NH 3 — ammonia; and C, four — CH 4 — "fire damp.'* Under different conditions, some elements show different powers of attraction toward the same element; so again this chemical society resembles social life. Sometimes N will hold to itself one atom of O, sometimes two, and sometimes three with an atom of H besides. 14 THE CHEMISTRY OF Exchange Value. The chemist must understand all these holding powers, which he calls the valence of an element; but to him the housewife may leave the thorough knowledge, while she recognizes that by virtue of this valence, compounds are formed with widely different qualities; thus, H 2 is pure water, while H 2 2 , hydrogen peroxide, is a disinfectant and a bleaching agent; S0 2 , sulphur dioxide, used for bleaching straw and fabrics, also a germicide, is a gas; while S0 3 is a white crystalline solid. Valence is a variable quality, but in uniting, or exchanging places with each other, the atoms of each element have a value which remains constant. This value is expressed in terms of a certain unit which chemists have chosen as a standard. At the outposts of the Hudson's Bay Territory all trade is on a system of barter or exchange, and therefore a basis of value is necessary. The skin of a beaver is agreed upon as the unit from which to count all values. A red fox skin is worth two beaver skins ; a silver fox skin is worth four beaver skins. All the hunter's transactions are based upon these values. If he wishes to purchase a knife, he must pay four beaver skins; a gun will cost him three silver fox or twelve beaver skins. The chemist's standard of value is the atomic weight of hydrogen. They choose this because it is the smallest relative weight known to enter into COOKING AND CLEANING. 15 combination with other elements. Having once accepted this arbitrary choice, all values are counted from its value. For the convenience of the reader, this exchangeable value will be indi- cated by Roman numerals over the symbols in the formulae given in this book, although this practice is not universal. The exchange value of other elements is found £o™ s bina " by experiment. For our present purpose, these elements may be divided into three classes with hydrogen for a connecting link. Exchange Values. Table I. Some common elements which unite with H: Chlorine CI 1 Iodine I 1 Bromine Br 1 1 Oxygen O 11 > +H 1 Sulphur S n Nitrogen N nI Carbon C™ H 1 unites with CI 1 , atom for atom, their values being the same. O n unites with two of H 1 , its value being twice that of H 1 ; while N m equals three of H 1 ; and C IV , four. 16 THE CHEMISTRY OF Table II. Some common elements which unite with each other and with compounds of H. Carbon C 1 ^ Oxygen O n Sodium Na 1 Potassium K 1 Calcium Ca 11 Chlorine CI 1 Nitrogen N HI Sulphur S« Phosphorus P v C™ unites with 2 n making C IV 2 n , carbon dioxide or carbonic acid gas; C IV 2 n unites with H 2 I O n forming H 2 I C iy 3 11 , carbonic acid gas in solution. Ca 11 unites with O n , forming Ca n O n , quicklime; Ca XI O n unites with H^O 11 , forming CanH^Oj, 11 , slaked lime. Table III. Some common elements which may be substi- tuted for H in a compound, thereby making a new compound : Sodium Na 1 Potassium K 1 Calcium Ca 11 Carbon C J V COOKING AND CLEANING. 17 Phosphorus P 111 or PV Tin SnH r Sn™ Zinc Zn" Sulphur S n Copper Cu 11 Lead Pb" Gold Auin Aluminum Al 11 or A1 IV H I C1 I is muriatic or hydrochloric acid. As Na 1 has the same value as H 1 , it may be substituted for it, and we have Na I Cl I , common salt. H 2 I C IV 3 11 is carbonic acid in solution. Na 2 * may be substi- tuted for the H 2 X forming Na^C^Og 11 , the com- mercial soda ash. Soda ash added to water and allowed to crystallize from it gives the familiar "washing crystals." H I N III 3 n is nitric acid. One atom of K 1 will replace the H 1 , forming K I N III 3 n , or saltpetre. Some of the compounds formed by the union Union and x Exchange. and exchange of these various elements are very familiar substances. "In the laboratory we never mix our materials at random, but always weigh out the exact propor- tions . . . for, if the least excess of one or the other substance over the proportions indicated is taken, that excess will be wasted. It will not enter into the chemical change."* It is this exact- *"The New Chemistry," p. 151. 18 THE CHEMISTRY OF ness in dealing with matter which gives to the study of chemistry its great value from an educa- tional standpoint. In the economy of nature noth- ing is lost. Wood and coal burn in our stoves. The invisible product of their combustion, C IV 2 n , passes into the air, but adds a definite amount to the weight of the air. Twelve pounds of coal (free from ash) in burning take from the air thirty- two pounds of oxygen and give back to the air forty-four pounds of carbon dioxide. Water is always composed of two atoms of hydrogen to one of oxygen, whether the quantity formed be one molecule or one million molecules. The water molecule, H^O 11 (atomic weights, H 2 T =2, O n =i6) weighs 18, then for every eighteen parts by weight of water, there will be two parts by weight of H 1 and sixteen parts by weight of O n . C IV 2 n , carbon dioxide, has one atom of carbon and two atoms of oxygen in each molecule ; while by weight, twelve parts are C IV and thirty-two are O n . The exchanges and interchanges among the elements according to these two laws of value and weight form chemical reactions. The written ex- pression of the reaction is called a chemical equa- tion. In all chemical equations there is just as much weight represented on one side of the sign of equality {—) as on the other. COOKING AND CLEANING. 19 C I v+0 2 II =Civo 2 n 12 + 32 Carbon. Oxygen. HiCl* + NaiO n Hi = Muriat- Caustic ic Acid. Soda. - 44 Carbon Dioxide. Na^l 1 + HJO" Sodium, Water. Chloride or Com- mon Salt. 36.5+40 =58.5+18 76.5=76.5 This shows that the sumi 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. These facts lead up to one of the fundamental laws of the present science of chemis- try — the Law of Definite Proportions: In any chemical compound the elements ahvays unite in the same definite proportion by weight. The atomic weights of elements united in a com- pound are then spoken of as the combining weights; thus, twelve and thirty-two are the com- bining weights of C IV and O n . Out of this first law grows a second — the Law of Multiple Propor- tions: When elements form more than one com- pound, they unite according to some multiple of their combining weights. As we have noticed, sulphur and oxygen form different compounds — S0 2 and SO s — where the combining weights are thirty-two to thirty-two 20 THE CHEMISTRY OF for the first and thirty-two to forty-eight for the second. These two laws are the corner-stones upon which all reactions are built. If we wish to obtain forty-four pounds of carbon dioxide (carbonic acid gas) we may, according to our first law, write out the reaction which we know will take place. c+o 2 =co 2 The combining weight of carbon is 12. One atom= 12 The combining weight of oxygen is 16. Twt> atoms= 32 C0 2 = 44 Then we must take twelve pounds of carbon and thirty-two pounds of oxygen to make our de- sired forty-four pounds of gas. Exchange of When more than two elements enter into corn- Groups. bination, it is common for two or more to band together. In such a case the group has an ex- change value of its own, which is not the sum of the values of its separate elements, but which is a constant value, dependent upon their values in a way which it is not necessary to explain here. These partnerships will be included in brackets, as (SOJ 11 , (C0 3 ) n , (NO.) 1 . These groups do not represent actual compounds, which exist alone, like lyO 11 , IPCl 1 , C IV 2 n , N^Cl 1 ; but the group COOKING AND CLEANING. 21 enclosed by the brackets passes from one com- pound into another as if it were one element. The numeral over the bracketed letters indicates the exchange value of the partnership, not the sum of the elements. A few illustrations will make this clearer. Table IV. Mineral acids and some of their common com- pounds : HiQi Hi(N0 3 ) 1 Muriat- Nitricj ic Acid. Acid. Compounds : NaiQi Salt. KJCNOs)! Saltpetre. H,i(SO0 n Sulphuric Acid. Ca«(SO0« Plaster of Paris. H,(CO,)" Carbonic Acid. Ca"(CO.)" Marble. Reactions among the above substances : H 2 i(S04) II +Caii(C0 3 ) II =Ca"(S04) n +H 2 i(C03) n H 2 i(SO 4 )n+2(Na I Q I )=Na,i(SO0 II +2(HiCli)i H 2 i(S04) II +NaiCl I =NaiHi(S04) II +HiCli It will be seen that the groups do not separate, but combine and exchange with the single ele- ments by the same laws which govern the com- binations among simpler substances. The last two equations show how, where there are two atoms of hydrogen which may be replaced, 22 THE CHEMISTRY OF either one or both can be exchanged for an atom of equal replacing value. The two compounds thus formed will differ in their properties. This will be more fully shown later on in the case of cream of tartar. COOKING AND CLEANING. 23 .2 s o x £ -o 6 6 tit "?>&* o u 33 + + + so ^c* so & ~£ ~£ >C o o • sd SK ~E * ^ d u o + £ ~a + ~ 3 ^ o -J d I w * m " .2 . -a if? u si oo o o <* X o 5 o 03 o o + q vO u < + d £ X S-"2 ^ + o < + o X ■^-u < ■* C$ C5 o O 73 + ■a £ /^\ O^.g-J u a d " | «otJ-q ~d ^ ^ < A ~B ^| aR * . ~d * a ~ _* ~e x ,s ^ « + + ^ ~0 rh ^O _^ CO rt CHAPTER III. 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 winter 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 iv+o 2 n = Civo 2 n C I VHJ+04 II =C I vo 2 II +2H 2 iO" These two chemical reactions indicate the 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 chemka! 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- 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 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 Starches. Sugars. 28 THE CHEMISTRY OF found in the milk of mammalia, while grape-sugar is a product of the ripening processes in fruit. 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 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. Starch Con- version. Ci 2 IV H 22 i0 1 i II +H 2 iO II +ferment=2C 6 IV H 12 i0 6 11 Cane-Sugar. Water. Dextrose and Levulose. Glucose and maltose are converted by yeast into Sugar m 111 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 2 i vh 6 i O" Alcohol. 2Civo 2 " Carbon Dioxide. The alcohol, if burned, would give carbon dioxide and water. 2C 2 IV H 6 I 0"+i20 11 = 4Civo 2 n -{-6H 2 I 11 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 +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. The same cycle of chemical changes goes on in the human 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. 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 tf&S* ° 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- Chemical Re- actions in Bread-Mak- ing. 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. 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. 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 , 1 • • , • • ofBread- maintained during the chemical process is an 1m- 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 IV H 6 iO I i+0 2 II =C 2 I VH 4 I 2 II +H 2 iOn 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. 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 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. 2NaiHiCivo 3 n +heat = Na 2 iC™O a n +H a iO"+CivOa« 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. NaiHiCiV0 3 II +HiCl I =NaiQ I +H 2 i0i I +C I V0 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 — all 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. The various 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. Cis^HsJOaH Stearic Acid in Suet. Cc^H^Os 11 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. 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 the insane, as well as of the criminal classes, show 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, then whatever we do to fats in the line of cooking them is liable to hinder rather than help their diges- Necessity of Fat in the Diet. The Digestion 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. Fats may be heated to a temperature far above that 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 ivork 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 Body a Machine. Calories. Need of Body Fuel. 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 FoodTtX 5 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 tgg, 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, w r hile 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 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. 51 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 Eggs. 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. 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. 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. COOKING AND CLEANING. 53 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- 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 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 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. The effect of cooking upon the solubility of the three important food-principals may be broadly stated thus : — COOKING AND CLEANING. 55 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. CHAPTER V. The Art of Cooking. Flavors and Condiments. THE 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. 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. 5*7 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 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 directly 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-Mittel. 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 J ° r for Digestion. 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 v°T- es °* them into suitable food for man comes under the Saliva - head of what has been called "external digestion. 1 " 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- :ion 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 bestforhuman 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 egg 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. THE CHEMISTRY OF 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. Nearly all, if not all, young animals live on food of 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. Experience leads to the conclusion that mankind COOKING AND CLEANING. 6? 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- Water 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. 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. It has been estimated that a growing person needs about one part of nitrogenous food to four oi 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., 257. 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»5oo. 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 , 2 57« 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 TO 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 OF Tyndall proved by delicate experiments £hat 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, all the 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 feet 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 simply a resting stage and are not reproduc- COOKING AND CLEANING. 75 tive; while, in molds, they bring forth an active, growing plant. The common puff-ball (Ly coper don), 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. Vita 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. 7? 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 earned 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. The third, or wild yeasts, are not usually trouble- some in the air or in the dust of the house, where ordinary cleanliness rules. 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. Molds, and some of the yeasts, destroy our prop- erty; 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 ini daily living. When the cause o-f 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 akvays 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. 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 air 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 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 thoughf, 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 82 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 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- 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- 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. 1 lons ° 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 OF Products of Combustion. Air Pollution. 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. The gaseous products of the combustion carried 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." 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 Ah-aSub- 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 Qelnness. 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. With these allies the victory over uncleanness might be easy and sure were dust alone the enemy to be fought; but 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, might 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 88 THE CHEMISTRY OF Processes of Cleaning. Girease-Oils. \lkali 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 the second process, 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 their 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 metak 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 (NHJOH, 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 Soaps. 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. 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 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. COOKING AND CLEANING. 93 Many housewives fear to touch the piano, how- a clean 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, the water and soap should be replaced by rotten- stone and oil, or dark lines will appear where the alkali and water 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 neither scratches nor grows linty. 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 washed with water. 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. 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 96 THE CHEMISTRY OF be scratched or worn away too rapidly. Metal 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 or soapstone may be washed like metal or scoured with any fine material. 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. A bag of coarsely woven cheese-cloth filled with indigo or other powdered blue may be dusted over glass. This, when rubbed hard with soft cloths or chamois, leaves a fine polish. 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. 97 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 thoroughly with dilute muriatic acid. Then 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 98 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. 00 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. fLofC. Grease. T CHAPTER III. Stains, Spots, Tarnish. '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. Grease-spots. 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 . . . Grease. 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 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. If pure, they are completely volatile and sel- dom affect colors. Whenever these solvents are used, it is well to place a circle of some absorbent material, like flour, crumbs of bread, blotting paper or chalk around the spot 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. A white cloth may be put under the stain to serve not only as an absorber of the grease and any excess of liquid, but also to show when the goods is clean. 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- "Dus^ 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 Ox-gaii. 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 Grease-spots . on Wood. 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 unfin- 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 on Grease or oil stains on painted walls, wall-paper Wall-paperor r r r Leather. 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 - House paints consist mainly of oils and some colored earth. 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 vanish 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 Spots made by food substances are greasy, sug- ary or acid in their character, or a combinatiuxi 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. 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, remem- Indelible Inks. Aniline Inks, Marble. no 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. 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 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 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- Alkalies. 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. 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- 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 in 1878 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 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, CaCO s , 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 wrth 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 silyer 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 of 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 and 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. 117 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 ma- terials used for silver. A paste is prepared by the dealers for this special use. > 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. CHAPTER IV. Laundry. THE 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. , 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. Rain-water absorbs more or less carbon dioxide from various sources and, soaking into the soil, often comes in contact with lime, magnesia and other compounds. Water saturated with carbon dioxide will dissolve these substances, forming carbonates or other salts which are soluble, and such water is known as "hard." Water for domestic uses is called either "hard" Hard and or "soft" according as it contains a greater or less quantity of these soluble salts. When soap — a chemical compound — is added to hard water, it is decomposed by the water; and the new compound formed by the union of the lime with the fatty acid of the soap is insoluble and is deposited upon the surface of any articles with which it comes in con- tact, i. Therefore, large quantities of soap must be used before there can be any action upon the dirt. It has been estimated that each grain of carbonate of lime per gallon causes an increased expenditure of two ounces of soap per ioo gallons, and that 120 THE CHEMISTRY OF the increased expense for soap in a household of five persons where such hard water is used, might amount to five or ten dollars yearly.* Temporary When the hardness is caused by calcium car- ana rerma- -' nent Hardness. bonate it is called "temporary" hardness, because it may be overcome by boiling. The excess of carbon dioxide is driven off and the lime precipi- tated. The same precipitation is brought about by the addition of sal-soda or ammonia. When the hardness is due to the sulphates of lime and magnesia, it cannot be removed by boiling or by the addition of an alkali; it is then known as "per- manent." Public water supplies are often softened before delivery to the consumers by the addition of slaked lime, which absorbs the carbon dioxide and the previously dissolved carbonate is precipitated. If this softening process be followed by filtration, the number of bacteria will be lessened, and the water, thereby, rendered still purer. All water for use with soap should, then, be naturally soft or made soft by boiling or by the addition of alkalies, ammonia or sal-soda. Soap - 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- * Water Supply, Wiiliam P. Mason, p. 366. 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 s a P 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 A rts and Manufactures. tutes. 122 THE CHEMISTRY OF 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. Tames Muspratt, of Liverpool, first Manufacture J r r of Soda-ash. 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. Washing soda should never be used in the solid 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 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 Medicine. 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, aveiie 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. 129 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 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. 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. R^f iron- 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 " 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 Not too hot nor too much water while the soap is acting upon the dirt; Thorough rinsing, that all alkali may be re- moved; 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 washing 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. Colored cottons should have their colors fixed 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. Dish cloths and dish towels must be kept clean 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 water 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 ol 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. Ideal cleanness requires the cleanness of the in- 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. 144 COOKING AND CLEANING. terested — pupils and teachers — should be expected and required as firmly as their cooperation in any- other department of education. 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. The Housekeeper's Laboratory or The Chemicals For Household Use. 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 example is the instant disappearance of all red iron-rust stains when treated with a drop of hydrochloric acid (the muriatic acid of the druggist). If, however, the acid is not completely 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 am- monia to the final rinsing water, which neutralizes any remaining acid, and the stained tray-cloth or sheet is perfectly whitened. The chemicals for household use are chiefly 146 THE CHEMISTRY OF acids, alkalies, and solvents for grease. Acids and alkalies are opposed to each other in their proper- ties, and if too much of either has been used, it may be rendered innocent, or neutralized by the other; as, when soda has turned black silk brown, acetic acid or vinegar will bring the color back. The acids which should be on the chemical shelf of the household are acetic, hydrochloric (muri- atic), oxalic, tartaric. Vinegar can be used in many cases instead of acetic acid; but vinegar con- tains coloring matters which stain delicate fabrics, and it is better to use the purified acid, especially as the so-called vinegar may contain sulphuric acid. Some bright blue flannels and other fabrics, when washed with soap or ammonia become changed or faded in color. If acetic acid or vin- egar be added to the last rinsing water, the orig- inal appearance may be restored. Not all shades of blue are made by the same compounds, hence not all faded blues can be thus restored. The use of these acids has been indicated in the previous pages, and there remains to be consid- ered, only certain cautions. Hydrochloric acid is volatile. It will escape even around a glass stop- per and will eat a cork stopper; therefore, either the glass stopper should be tied in with an im- pervious cover — rubber or parchment — or a rub- COOKING AND CLEANING. 147 ber stopper used, for the escaping fumes will rust metals and eat fabrics. Oxalic acid should be labeled poison. The bleaching agents, "chloride of lime," cal- cium hypochlorite, sodium hypochlorite, sodium hyposulphite (thiosulphite), owe their beneficent effect to substances of an acid nature which are liberated from them, and the clothes should be rinsed in a dilute alkali to neutralize this effect. They should all be used in solution only, and should be kept in bottles with rubber stoppers. Sulphurous acid gas (S0 2 ), obtained by burn- ing sulphur, is also a well-known agent for bleach- ing. It will often remove spots which nothing else will touch. The amount given off from a burning sulphur match will often be sufficient to remove from the fingers fruit stains or those made by black kid gloves. The alkalies which are indispensable are : ist. Ammonia, — better that of the druggist than the often impure and always weak "household ammonia." The strong ammonia is best diluted about one half, since it is very volatile, and much escapes into the air. 2d. Potash, which is found at the grocers in small cans. - The lye obtained from wood ashes owes its caustic and soap-making properties to this substance. Potash is corrosive in its action, and must be used with discretion. 148 THE CHEMISTRY OF Crystallized sodium carbonate, the sal-soda of the grocer, is not, chemically speaking, an alkali, but it gives all the effect of one, since the car- bonic acid readily gives place to other substances. Sal-soda is a very cheap chemical, since it is readily manufactured in large quantities, and forms the basis of most of the washing powders on the market. With grease, it forms a soap which is dissolved and carried away. 3d. Borax is a compound of sodium with boric acid, and acts as a mild alkali. It is the safest of all the alkalies, and affects colored fabrics less than does ammonia. Solvents for grease are alcohol, chloroform, ether, benzine, naphtha, gasolene — all volatile — kerosene and turpentine. Of these chloroform is the most costly, and is used chiefly for taking spots from delicate silks. Fabrics and colors not in- jured by water may be treated by alcohol or ether. Benzine, naphtha or gasolene are often sold, each under the name of the other. If care is taken to prevent the spreading of the ring, they can be safely used on any fabric. They do not mix with water, and are very inflammable. The less volatile solvents are kerosene and tur- pentine. Kerosene is a valuable agent in the house- hold, and since some of the dealers have provided a deodorized quality, it should find an even wider COOKING AND CLEANING. 149 use. The lighter variety is better than the 150 degree fire test, which is the safe oil for lamps. As has been indicated in the preceding pages, the housewife will find many uses for this common substance. On account of the purity and cheapness of kero- sene, turpentine is less used than formerly, al- though it has its advantages. These household chemicals should have their own chest or closet, as separate from other bottles as is the medicine chest, and especially should they be separate from it. Many distressing accidents have occurred from swallowing ammonia by mis- take. In addition to these substances, certain others may be kept on hand, if the housewife has sufficient chemical knowledge to enable her to detect adul- teration in the groceries and other materials which she buys. A few of these simple tests are given with the chemicals needed. Directions for Using the Housekeeper's Laboratory. When directed to make a solution acid or alka- line, always test it by means of the litmus paper: — Blue turned to red means acid. Red turned to blue means alkaline. 150 THE CHEMISTRY OF Only by following the directions can the test be relied upon. Under other circumstances than those given, the results may mean something else. Use the acids in glass or china vessels only. Metals may be attacked. Do not touch brass with ammonia. To test for sulphuric acid or soluble sulphate in soda, cream of tartar, baking powder, vinegar, sugar or syrup: Add muriatic acid (HC1) to the solution (if the insoluble part is sulphate of lime, it will dissolve in HC1 on heating), then add barium chloride (BaCl 2 ). A heavy white precipitate proves the presence of sulphuric acid, either free or combined. If the solution is not distinctly acid at first, it is not free. To test for lime in cream of tartar, baking pow- der, sugar or syrup: Make the solution alkaline with ammonia and ammonium oxalate. A fine white precipitate proves presence of lime. Good cream of tartar will dissolve in boiling water, and will show only slight cloudiness when the test for lime is applied. To test for phosphates in cream of tartar or bak- ing powder: Make acid by nitric acid (HNO s ), and add ammonium molybdate; A fine yellow pre- cipitate or yellow color proves presence of phos- phates. To test for chlorides in soda, baking powder, COOKING AND CLEANING. 151 sugar, syrup or water : Make the solution (a fresh portion) acid with nitric acid (HNO s ), and add sil- ver nitrate (AgN0 3 ). A white, curdy precipitate or a cloudiness indicates chlorides. To test for ammonia in baking powder: Add a small lump of caustic potash to a strong water solution. Red litmus will turn blue in the steam, on heating. To test for alum in cream of tartar, baking pow- der or bread: Prepare a fresh decoction of log- wood; add a few drops of this to the solution or substance, and render acid by means of acetic acid (C 2 H 4 2 ). A yellow color in the acid solution proves absence of alum. A bluish or purplish red, more or less decided, means more or less alum. If the label of a washing powder claims it to be something new, and requires that it be used with- out soda, as soda injures the clothes, it can be tested as follows: Put half a teaspoonful of the powder into a tumbler, add a little water, then a few drops of muriatic acid. A brisk effervescence will prove it to be a carbonate, and if the edge of the tumbler is held near the colorless flame of an alcohol lamp, the characteristic yellow color of sodium will appear and complete the proof. If the acid is added, drop by drop, until no more effer- vescence occurs, and there remains a greasy scum on the surface of the liquid in the tumbler, the 152 COOKING AND CLEANING. compound contains soap as well as sal-soda, for the acid unites with the alkali of the soap and sets free the grease. If some very costly silver polishing powder is offered as superior to all other powders, a drop or two of muriatic acid will decide whether or not it is chalk or whiting, (CaC0 3 ) by the effervescence or liberation of the carbonic acid gas. Caution! Use a new solution or a fresh por- tion of the first one for each new test. This it is essential to remember. To judge of the quantity of any of the sub- stances, it is necessary to have a standard article with which to compare the suspected one. Take the same quantity of each, and subject each to the same tests. A very correct judgment may thus be formed. Besides this laboratory there should be in every household an emergency case, placed in an accessible and well-known cupboard, but out of the reach of children. It should be plainly labeled and kept stocked with the various solu- tions, plasters, ointments, etc., with which the house-mother soothes wounded nerves as well as bruised noses. BOOKS OF REFERENCE. Consulted in the Revision of the Chemistry of Cooking and Cleaning. Foods: Composition and Analysis A. W. Blyth Dietetic Value of Bread John Goodfellow Food, Manuals of Health Albert J. Bernays Food and Its Functions James Knight Analysis and Adulteration of Foods James Bell Food A. H. Church Foods and Feeding Sir Henry Thompson The Chemistry of Cookery W. Mattieu Williams Chemistry of Wheat, Flour and Bread and Tech- nology of Bread Making Wm. Jago The Spirit of Cookery J. L. W. Thudichum Food in Health and Disease I. Burney Yeo Diet in Sickness and Health Mrs. Ernest Hart Chemistry and Economy of Food, U. S. Dept. Agriculture, Bulletin 21, 1895 W. O. Atwater Also Bulletins 28, 29, 31, 35, 37. Farmers' Bulletins 34, 42. Dietetics Gilman Thompson Practical, Sanitary and Economic Cooking Mrs. Mary Hinman Abel How to Feed Children Louise E. Hogan The Science of Nutrition Edward Atkinson Food Materials and Their Adulterations Ellen H. Richards 154 BOOKS OF REFERENCE. Handbook of Invalid Cooking Mary A. Boland The Young Housekeeper Maria Parloa Chemie der menschlichen Nahrungs und Genus- mittel J. Koenig Physiological Chemistry of the Animal Body Arthur Gamgee A Text-book of Physiological Chemistry. . .Hammarsten Chemistry of Daily Life Lassar Cohn Organic Chemistry Remsen Inorganic Chemistry Remsen Dust and Its Dangers T. Mitchell Prudden The Story of the Bacteria T. Mitchell Prudden The Story of Germ Life Prof. H. W. Conn Home Sanitation. .Ellen H. Richards and Marion Talbot Household Economics Mrs. Helen Campbell How to Drain a House George Waring Homes and All About Them E. C. Gardner The House that Jill Built E. C. Gardner From Attic to Cellar Mrs. Eliz. F. Holt The Art of Laundry Work Florence R. Jack The Micro-Organisms of Fermentation Alfred Jorgensen Our Secret Friends and Foes Percy Frankland Housework and Domestic Economy. .. .M. E. Haddon Emergencies and How to Meet Them J. W. Howe Manual of Lessons on Domestic Economy. .. .H. Major Handbook of Sanitary Information Roger S. Tracy, M. D. The Food Products of the World... Dr. Mary E. Green Le Pain et la Panification Leon Boutroux Eating and Drinking Albert H. Hoy, M. D. Text-Book of Am. Physiology Prof. Wm. Howell INDEX. Absorbents of grease, ioo, 101 Acids, 16, 17, 21, 41, 146 Acetic, 38 Butyric, 35 for iron stains, 132 Mineral, 21. Muriatic or Hydrochloric, 13, 17, 19, 41, 132, 146 Oxalic, 116, 147 Stearic, 43 Tannic, 50 Air, a substance, 85 as food, 67 not the agent of change, 73 pollution of, 84 pure, 83 Albumin, 49 Albuminoids, 50 Alcohol, 30, 36 Alcohol, as solvent, 102, no, 148 product of fermentation, 30, 36, 38 Alkalies, caustic, 89, in Volatile, 89 Alkali metals, 88 Aluminum, 117 Ammonia, 89 uses of, 73, 93, 102, 125, 139, 147 Ammonium, 88, 89 Animal body, a living machine, 47 repair of, 48 Art of cooking, 56, 62 Atoms, 5, 11 Atomic weight, 10, 11 of hydrogen, 14 Bacteria, 36, 39, 74, 76, 77, 81 action x>f in disease, 80 as flavor producers, 62 food of, 81 spores of, 75 Bacteriology of bread-making, 36 Baking powder, 23 Beans, 52, 64 Beer, 29 Benzine, 98, 102, 148 Biscuits, 39 Bleaching, 134, 135 Bleaching powder, 135 (See chloride of lime and Javelle Water) Blinds, 82 Blood-stains, 106, 129 Blotting paper for ink, 108 Bluing, 133, 134 Books for reference, 153 Borax, 125, 128, 137, 139, 148 Brass, 116 Bread-making, chemical reactions in 29, 30, 36 Bread, as food, 33 crust, 39 fermented, 36 flavor in, 39 ideal, 34 home made, 37 leavened, 35 object of baking, 38 reason for kneading, temperature of baking, 37, 38, 39, 34 » of fermentation, 37 stale, 39 Butter, 43 Butyric acid, 35 cream of tartar, 41, 42 Caesium, 88 Calcium hypochlorite, 128 Calories, 47 Cane sugar, 28, 29 Carbohydrates, 26, 44, 63 Carbon dioxide (carbonic acid gas), 16, 17, 18, 19,20, 25,30, 36, 37 method of obtaining, 40 Casein, 52 Caustic alkalies, 89 Cayenne pepper, 59 Cellulose, 27 Cheesecloth for cleaning, 93 Chemical arithmetic, 18, 21 Chemical change, 3, 10, 28 produces heat, 25 Chemical elements, tables of, 15, 16, 17 156 INDEX. Chemical elements, laws of combina- tion, 19 equations, 18, 21 Chemical Laws, 10, 13 Chemical reaction, 21, 25 reactions in bread and beer making, 36 Chemical Symbols, n Chemicals for household use, 145 Chloride of lime, 126, 127, 128, 129, , 147 Chlorine, 13 Chloroform, 102, 148 Cleaning of brass, 116 fabrics, 97, 98 glass, 96 paint, 93 silver, in, 116 wood, 90, 91, 92, 93 powders, 113 problems of, 90 processes of, 88, 90 Cleanness, ideal and sanitary, 142 of school houses, 144 personal, 143 philosophy of, 82, 85 public, 144 Cocoa and coffee stains, 127, 128 Collagen, 50 Colors, setting of, 140, 146 Combustion of food, 25, 26 products of, 84 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 Cottonseed oil, 43 Cream of tartar, 23, 41, 42 Decomposition, 64 Definite proportions, laws of, 19 Development of flavor, 56 Dextrose, 29 Diatase, 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 Dust, 71, 72,73, 75,87, 88 composed of, 77 germs, 80 in air, 72, 76 meteoric, 73 on fabrics, 97, 98 on wood, 92 spots, 103 Economy in cooking, 60 of mixed diet, 65 Effect of cooking, 54 of condiments, 58 Eggs, 51 Elements, Chemical, 9 Energy, sources of, 44 mechanical unit of, 47 Ether, 102, 148 Exchange value, 14, 15, 17, *o Expansion of gases, 6 of water, 40 Fabrics, 97, 98 Fat, effect of high temperature on, 46 digestion of, 44 in diet, 44 Fats, 24, 43, 45, 55, 88 Fermentation, 33, 39 Finish of woods, 90 Flavor, 46, 56, 57, 58, 60 Flour, use of in bread, 39 Food, office of, 24, 69 water and air as, 68 Forces causing change, 4 Fruit stains, 126, 137 Fuel in body, 47 Fungi, 74 Gases, 3 Gasolene, 148 Germs, 74, 80, 81 Glass, 96 Glucose, 29 Gluten, 52 Grass stains, T29 Grease, 87, 88, 100, 101, 102, 104, 135 INDEX. 161 Grease, on wood, 103 solvents for, 91 Groups of elements, 20 Growth, nitrogenous food required for, 48 Gums, 24 Heat produced by chemical change, 24 source of in animals, 25 Housekeeper's laboratory, directions for using, 149-152 Hydrochloric acid, (see muriatic) Hydrogen, 9, 27, 44 Ideal bread, 34 Indigo, 133 Inflammable substances, 98 Ink indelible, 109 stains, 107, 108, 131 Inoculation, 82 Iron rust, removal of, ir7, 131, 132, MS Javelle Water, 126, 127, 128, 129, 130 Jewelry, 115 Kerosene, 91,92, 96, in, 116, 117, 131, 141, 148, 149 Kitchen utensils, 117 Laboratory, housekeeper's, 149 Lard, 43 Laundry, 118-142 Law of Combination, 13 definite proportion, 19 multiple proportion, 19 Leather, 94 Leaven, 35 Legumin, 52 Lentils, 65 Levulose, 29 Lithium, 88, 89 Marble, 95, 109 Matter, changes in, 1, 2, 3, 4 definition of, 1 forms of, 3 states of, 5 Medicine stains, 127 Metals, 95, in, 116 Mildew, 130 Milk stains, 129 Mineral acids, 21 Mixed diet, 65 Molds, 74, 77, 79 Molecular weight, n Molecules, 5, 6, n Mucous stains, 129 Muriatic acid, 41 Naphtha, 148 Nature's scavengers, 78 Nickel, 117 Nitrogen, 48 Nitrogenous food, 47, 49,68 cooking of, 50, 55 Oils, 43, 45, 88, 92 Oil finish, 91 Oil Stains, 130 Olive Oil, 44, 45 Oxalic acid, 147 Ox-gall, 103 Oxygen, g, 26, 43 Oysters, 51 Paint, 93, 104 Paper, 94 Pastry, 54 Pathogenic germs, 81 Pearlash, Pepsin, 64 Peptones, 64 Physical change, 2, 3 Pitch, 105 Plated silver ware, 112 cyanide, 113 Plumbing, care of, 141 Porcelain, 96, no Potash, 103, 122, 123, 147 Potassium, 88 Preparation for food, of starch, sugar and fat, 24 Prevention, 80, 98 Principles of diet, Products of decomposition, 64 Proportion of nitrogenous food re- quired, 68 Pumice, 95 Rations, 69 Reference books, 153 Removal of dust, spots and stains, 87 Restoring color, 97 Rubidium, 88 Rust of iron, 117 Saliva, 63 Sal-soda, 148 Salt, 7, 41, 42 School house sanitation, 143 158 INDEX. Seasonable diet, 65 Serving, 62 Shellac, dissolved by alcohol, in Silver, cleaning of, in, 113, 114,115 nitrate, polish, 113, 114 Silver-ware, 112, 115 Soap, 89, 120, 122, 124, 137, 139 bark, 121 berry tree, 121 Soda, 7, 42, 122, 124 Soda ash, 17, 123, 124 Sodium, 87 Sodium carbonate, 148 Solution, 6, 7, 28, 50, 81 Solvents, 78, 91, 101, 102, 106, 148 Source of energy, 44 Spores, 75 Spots, 100, 118 Stains, 100, 106, 118, 126, 127, 128 Starch, 24, 27, 28, 29, 30, 31 cooking of 32, 55,61 Stearic acid, 43 Stimulants, 60 Stoves, care of, 117 Sugar, 2, 24, 27, 29 cane, 28 fruit, 28 milk, 27, 28 Suet, 43 Sulphur fumes, 127, 147 Sunlight, 82, 83, 84, 85 Symbols, 11, 12, Syrups, 7 Tables, 15, 16, 17, 21, 23 Tannin, 128 Tarnish, 100, 101 Tea stains, 127, 128 Temperature, 26, 46, 49, 52, 53 Turpentine, 91, 102, 103, 126, 148 Ultramarine, 133, 134 Unit of value, 14 Utensils, Kitchen, 117 Valence, 14 Varnish, 91, 105 Vegetables, 60 Wall paper, 94 Washing-Soda, 124, 125 Water, 18, 118, 119, 120 as food, 67 hard, 119, 120 Wax, 91, 105 Whiting, 114 Wine stains, 121 Wood finish, 90, 91, 92 Woolens, washing of, 139 Yeast, 33, 35, 36, 37, 38, 74, 78 H144 79 *| * Y/zn >-\ V s y _ ** •..•• a<> ; ^ '"• ^ <^ /i\V4 % t± «°-* r oV «°^ 4 CL a0 »!••«* V V % **!^'* u-^ .^-V ^ v «by* r ** < ^o/ LIBRARY OF CONGRESS 014 357 745 4*-