CHAPTER XXVI.
CHEMISTRY AND ALCHEMY—CHEMICAL COMBINATIONS—THE ATMOSPHERIC AIR.
We have in the foregoing pages given some experiments, and considered several of the metals, but there are numerous very interesting subjects still remaining; indeed, the number is so great that we can only pick and choose. All people are desirous to hear something of the atmosphere, of water, and the earth; and as we proceed to speak of crystals and minerals, and so on to geology, we shall learn a good deal respecting our globe—its conformation and constituents. But the atmospheric air must be treated of first. This will lead us to speak of oxygen and nitrogen. Water will serve to introduce hydrogen with a few experiments, and thus we shall have covered a good deal of ground on our way towards various other elements in daily use and appreciation. Now let us begin with a few words concerning Chemistry itself.
At the very outset we are obliged to grope in the dark after the origin of this fascinating science. Shem, or “Chem,” the son of Noah, has been credited with its introduction, and, at any rate, magicians were in Egypt in the time of Moses, and the lawgiver is stated by ancient writers to have gained his knowledge from the Egyptians. But we need not pursue that line of argument. In more modern times the search for the Philosopher’s Stone and the Elixir of Life, which respectively turned everything to gold, and bestowed long life upon the fortunate finder, occupied many people, who in their researches no doubt discovered the germs of the popular science of Chemistry in Alchemy, while the pursuit took a firm hold of the popular imagination for centuries; and even now chemistry is the most favoured science, because of its adaptability to all minds, for it holds plain and simple truths for our every-day experience to confirm, while it leads us step by step into the infinite, pleasing us with experiments as we proceed.
Alchemy was practised by numerous quacks in ancient times and the Middle Ages, but all its professors were not quacks. Astrology and alchemy were associated by the Arabians. Geber was a philosopher who devoted himself entirely to alchemy, and who lived in the year 730 A.D. He fancied gold would cure all disease, and he did actually discover corrosive sublimate, nitric acid, and nitrate of silver. To give even a list of the noted alchemists and magicians would fill too much space. Raymond Sully, Paracelsus, Friar Bacon, Albertus Magnus, Thomas Aquinas, Flamel, Bernard of Treves, Doctor Dee, with his assistant Kelly, and in later times Jean Delisle, and Joseph Balsamo (Cagliostro), who was one of the most notorious persons in Europe about one hundred years ago (1765-1789), are names taken at random; and with the older philosophers chemistry was an all-absorbing occupation—not for gold, but knowledge.
The revelation was slow. On the temperature of bodies the old arts of healing were based—for chemistry and medicine were allies. The elements, we read, existed on the supposition “that bodies were hot or cold, dry or moist”; and on this distinction for a long time “was based the practice of medicine.” The doctrine of the “three principles” of existence superseded this,—the principles being salt, mercury, and sulphur. Metals had been regarded as living bodies, gases as souls or spirits. The idea remained that the form of the substance gave it its character. Acid was pointed; sweet things were round.
Chemistry, then, has had a great deal to contend against. From the time of the Egyptians and Chinese, who were evidently acquainted with various processes,—dyeing, etc.,—the science filtered through the alchemists to Beecher and Stahl, and then the principle of affinity—a disposition to combine—was promulgated, supplemented in 1674 by Mayow, by the theory of divorce or analysis. He concluded that where union could be effected, separation was equally possible. In 1718 the first “Table of Affinities” was produced. Affinity had been shown to be elective, for Mayow pointed out that fixed salts chose one acid rather than another. Richter and Dalton made great advances. Before them Hales, Black, Priestley, Scheele, Lavoisier, and numerous others penetrated the mysteries of the science whose history has been pleasantly written by more than one author who we have not been able to consult, and have no space to do more than indicate. In later days Faraday, De la Rive, Roscoe, and many others have rendered chemistry much more popular, while they have added to its treasures. The story of the progress of chemistry would fill a large volume, and we have regretfully to put aside the introduction and pass on.
Before proceeding to investigate the elements, a few words concerning the general terms used in chemistry will be beneficial to the reader. If we look at the list of the elements, pp. 308-9, we shall see various terminations. Some are apparently named from places, some from their characteristics. Metals lately discovered by the spectroscope (and recently) end in ium; some end in “ine,” some in “on.” As far as possible in late years a certain system of nomenclature has been adhered to, but the old popular names have not been interfered with.
When elements combine together in certain proportions of each they receive certain names. The following table will explain the terms used ; for instance, we find that—
| Compounds of | Oxygen | are termed | Oxides, as oxide of copper. |
| ” | Hydrogen | ” | Hydrides, as hydride of potassium. |
| ” | Chlorine | ” | Chlorides, as chloride of sodium. |
| ” | Nitrogen | ” | Nitrides, as nitride of boron. |
| ” | Bromine | ” | Bromides, as bromide of potassium. |
| ” | Iodine | ” | Iodides, as iodide of potassium. |
| ” | Sulphur | ” | Sulphides, or Sulphurets, as sulphuret of lead. |
| ” | Selenium | ” | Selenides, as selenide of mercury. |
| ” | Carbon | ” | Carbides, or Carburets, as carbide of nitrogen, and so on. |