Cosine

“ Of equal scientific interest, however, and often of great commercial importance is the determination of the percentage of other acids and bases present. The analyst is often called on, in the examination of these bodies, to make known the content of water both free and combined, of organic and volatile matter, of carbon dioxid, sulfur, chlorin, fluorin, silica, iron, alumina, calcium, manganese, magnesia, and the alkalies. The estimation of some of these bodies presents problems of considerable difficulty, and it would be vain to suppose that the best possible methods are now known. ”

“ If sodium be thrown on to water, caustic soda is produced, a substance made up of hydrogen, oxygen, and the simple radicle sodium; by another reaction a substance can be obtained consisting of hydrogen, oxygen, and the compound radicle nitryl (NO2) . These two bodies have analogous formulæ, Na OH and (NO2) OH, they may both be regarded as derived from water, H HO, by the replacement of one half of the hydrogen by a radicle; in one case by Na, in the other by NO2. Again, the whole of the hydrogen in water may be replaced by sodium, with production of the compound sodium oxide, Na2O. ”

“ As in fermentation, spontaneous or excited, there is a sensible escape of carbonic acid gas, or fixed air, it may not be improper to note, that fermentable, or saccharine matter, consists of about twenty-eight pounds of carbon, eight pounds of hydrogen, and sixty-four pounds of oxygen, reducible into fixed, inflammable, and vital air, weighing one hundred subtile pounds in toto, or that every one hundred subtile pounds of saccharine matter consists of such proportions of these airs and gasses. ”

“ Why does grain lodge?
What is the most important compound of chlorine?
This is sand, the base of flint. It is necessary for the growth of all plants, as it gives them much of their strength. In connection with an alkali it constitutes the hard shining surface of corn stalks, straw, etc. Silica unites with the alkalies and forms compounds, such as silicate of potash, silicate of soda, etc., which are soluble in water, and therefore [Pg 37] available to plants. If we roughen a corn stalk with sand-paper we may sharpen a knife upon it. ”

“ Chemists, as we have said, understand by organic radicals certain groups of atoms of carbon and hydrogen, which are capable of combining with an atom of hydrogen in the same manner as an atom of bromine, or iodine, or chlorine, or which may be substituted for an atom of one of these substances in one of its combinations. In a complex body like rosaniline, one or more atoms of hydrogen may be removed and replaced by as many atoms of the organic radical. MM. Girard and De Laire caused aniline to react upon rosaniline. Aniline is an organic base, an ammoniacal compound. ”

“ I need take no notice of the modifications derived from a mixture of animal matter in these experiments, as it is not my desire to enter into a discussion of the general question, but to state such chemical facts as arose in the experiments I undertook. And since it is certain that vegetables alone are competent to the production of bitumen, and that the geological history of coal does not justify a supposition that animals have been concerned in its production, it is perhaps unnecessary to investigate that question further. ”

“ The body formed in the latter case is chemically the same as that produced in the former, there being present the same weight of calcium, the same weight of oxygen, and the same weight of silicic acid in each. Again, if to a solution of silicate of soda, one containing a soluble lead salt, such as the nitrate, be added, the silicic acid will unite with the oxide of lead in the nitrate of lead, and the acid constituent of that body will unite with the oxide of sodium or soda, forming nitrate of soda. ”

“ From what may the first class of proximates be formed?
The first class (those compounds not containing nitrogen) comprise the wood, starch, gum, sugar, and fatty matter which constitute the greater part of all plants, also the acids which are found in sour fruits, etc. Various as are all of these things in their charac [Pg 45] ters, they are entirely composed of the same ingredients (carbon, hydrogen and oxygen) , and usually combined in about the same proportion. ”

“ The mineral springs are received into a square cistern from whence they are conducted into the bathing rooms; they are extremely clear, unctuous to the touch, taste slightly acid, and emit a sulphureted hydrogen odour: air bubbles continually ascend with the water, and break as they reach the surface. The waters are found on analysis to contain carbonic acid, and muriate of Soda, in excess; a very small quantity of sulphate and muriate of lime, and muriate of Barytes. ”

“ Four are non-metallic solids: carbon, sulfur, phosphorus and silicon. Three of these, hydrogen, oxygen and carbon, making up the bulk of the plant, are obtainable ad libitum from the air and water. The other ten in the form of salts are dissolved in the water that is sucked up from the soil. The quantity needed by the plant is so small and the quantity contained in the soil is so great that ordinarily we need not bother about the supply [Pg 38] except in case of three of them. They are nitrogen, potassium and phosphorus. ”

“ If a concentrated solution of pure casein is exposed to the air it rapidly putrefies, and passes through a series of changes that I must not tarry to describe, beyond stating that ammonia is given off, and some crystalline substances, such as leucine, tyrosine, &c., very interesting to the physiological chemist, but not important in the kitchen, are formed.
A solution of casein in water is not coagulated by boiling; it may be repeatedly evaporated to dryness and [129] redissolved. ”

“ A plant requires certain chemical elements for its growth and all of these must be within reach of its rootlets, for it will accept no substitutes. A wheat stalk in France before the war had placed at its feet nitrates from Chile, phosphates from Florida and potash from Germany. All these were shut off by the firing line and the shortage of shipping.
Out of the eighty elements only thirteen are necessary for crops. Four of these are gases: hydrogen, oxygen, nitrogen and chlorine. Five are metals: potassium, magnesium, calcium, iron and sodium. ”

“ The coagulation which occurs in the living stomach when milk is taken as food appears to be due to the lactic acid of the gastric juice.
Casein, when thoroughly coagulated by rennet, then purified and dried, is a hard and yellowish hornlike substance. It softens and swells in water, but does not dissolve therein, nor in alcohol nor weak acids. Strong mineral acids decompose it. Alkalies dissolve it readily, and if concentrated, decompose it on the application of heat. When moderately heated, it softens and may be drawn into threads, and becomes elastic ”

“ In the cases of the sour-kraut and the ripening pear there is acid at work upon the fiber, which, as I have before stated, assists in the conversion of such indigestible fiber into soluble and digestible dextrin and sugar; but the demand for the solution of the vegetable casein or legumin, which has such high nutritive value and is so abundant in peas, etc., is of the opposite kind. Acids solidify and harden casein, alkalies soften and dissolve it. ”

“ In all, the chief nutritive ingredients of plants, except nitrogen, are present in traces only; chlorids, nitrates and sulfates of sodium and magnesium form the bulk of the permanently soluble matter, with usually a considerable proportion of calcic (and magnesic) carbonate, depending upon the amount of the earth-carbonates present in the soil, as well as upon that of oxidizable organic matter from which carbonic acid can be formed. ”

“ The comparatively fixed class, as regards diffusion, is represented by a different order of chemical substances (marked out by the absence of the power to crystallise) , which are slow in the extreme. Among the latter are hydrated silicic acid, hydrated alumina, and other metallic peroxides of the aluminous class, when they exist in the soluble form; with starch, dextrine, and the gums, caramel, tannin, albumen, gelatin, vegetable and animal extractive matters. Low diffusibility is not the only property which the bodies last enumerated possess in common. ”

“ In treating of the food of plants, it has been already observed that the fixed or mineral constituents which are contained in their ash, are necessarily derived exclusively from the soil, but that the carbon, hydrogen, nitrogen, and oxygen, of which their organic part is composed, may be obtained either from that source or from the air. ”

“ Through all these processes, in which we have observed the hydrocarbons decomposing one another, and forming new compounds, we have found that the chemistry of coal does not always have to borrow its powerful reagents, its acids and alkalies, from mineral chemistry; but that the compounds of carbon themselves, closely allied in constitution and properties, are very frequently capable of reacting upon and transforming one another, without the intervention of foreign agents. ”

“ Twenty grams of the soil are taken and the organic matter destroyed by incineration. In a flask of 200 cubic centimeters capacity, are placed thirty cubic centimeters of water and, little by little, some hydrochloric acid for the purpose of decomposing the calcium carbonate. When effervescence has ceased ten cubic centimeters of the same acid are added and boiled for half an hour, filtered, washed, and the wash-water and filtrate evaporated to dryness in a porcelain dish. ”

“ The answer, as I learned from Loa, was that the native clothing, and likewise the food, was manufactured synthetically. From the most ordinary chemical ingredients—from oxygen and hydrogen as contained in water, from carbon as contained in carbon dioxide or in coal, from the nitrogen found in the air, and from the sulphur and phosphorus of the mines—they would create compounds resembling natural organic products. ”

“ Hydrogen, carbonic acid, nitrogen, and methane occur, and cause a characteristic effect which is frequently deleterious to the flavour of the milk and its products. Most of the gas-producing ferments are members of the lactic acid group, and are sometimes classified in a group by themselves. In cheese-making the gases create the pin-holes and air-spaces occasionally seen. ”

“ After moistening with concentrated hydrochloric acid the mass is boiled with water, filtered, and the filtrate examined according to the ordinary methods for silicic acid, alumina, iron, lime, magnesia, and alkalies. The residue after 356treatment with concentrated sulfuric acid is dried, but not ignited, and boiled with a concentrated solution of sodium carbonate with the addition of a little caustic soda, filtered, heated, and the silicic acid separated from the solution. ”

“ It is absolutely necessary for the successful application of the preceding formulæ that the substances employed should be perfectly free from impurities, more particularly those of a mineral kind. The litharge, oxide of lead, and carbonate of lead, above all things, must be entirely free from oxide of tin, as the smallest particle of that substance may impart a ‘milkiness’ to the paste. All the ingredients must be separately reduced to powder, and, after being mixed, sifted through lawn. ”

“ The conditions necessary to bring a solid substance into a colloidal mixture with some liquid, or, in other words, to produce a suspensoid sol, require that the proportion of liquid to solid shall be large and some means of disintegrating the material which is to be dispersed into very fine particles. Many common chemical reactions, if carried out in very dilute solutions, result in the production of sols, especially if a small amount of some emulsoid is present in the reacting mixture ”

“ When, on the other hand, one compound body is so changed as to be converted into two or more substances different from itself, it is decomposed. Carbon, hydrogen, &c., are chemically combined in the interior of the plant during the formation of wood: wood, again, is decomposed when by the vinegar-maker it is converted among other substances into charcoal and wood-vinegar, and the flour of grain when the brewer or distiller converts it into ardent spirits. ”

“ The cells of the roots, like hewers and miners, sink numerous shafts in the spaces assigned to them, drive their galleries toward all points of the compass, in order to break up these mineral treasures, separate them from the incasing stone, and set the machinery of service in motion; day and night with inexhaustible diligence, they extract atom by atom of potash and ammonia, phosphoric and nitric acid, and, without working up their ore, deliver it over to the conducting vessels which transmit it by their powerful system of sucking and forcing pumps to the stem and the leaves. ”

“ Instead of acids uniting with bases to give rise to a third kind of bodies, salts, we have carburets, bases, uniting by twos or by threes, with or without the loss of one of their elements, and forming double or triple molecules of compounds, which may still be of the same chemical type. ”

“ We may get an idea of the nearly similar composition of the coal produced by very different plants or parts thereof, in remarking that as the cells, fibers, and vessels are formed of cellulose, and some of them isomeric, the difference in composition is especially connected with the contents of the cells, canals, etc., such as protoplasm, oils, resins, gums, sugars, and various acids, various incrustations, etc. ”