It will be seen from the above that the modern science of chemistry overlaps other sciences in many directions—physics, biology, astronomy, etc. These sciences are to a certain extent now inter-woven and inter-blended. Where the one ends and the other begins it is hard to say. Again we see the importance of co-operation in these various fields of inquiry!
THE NATURE OF MATTER
These newer researches in chemistry have finally enabled us to realize the ultimate constitution of matter; we have seen that it is composed of atoms, but these atoms themselves are complex things; they in turn are composed of electrons, and in the last analysis matter may be said to be non-existent! It has been resolved into electricity. But this conception of matter has also enabled us to explain many things before inexplicable—chemical combination, radio-activity, and what not. The world-old problem as to the nature of matter has at last been solved. It now devolves upon the physicist to explain the ultimate nature of electricity!
Matter, then, in a sense, can dissociate, disintegrate, dematerialize. It can also integrate, materialize, come into existence. Matter can be made to vanish and reappear. The old law of the “indestructibility of matter” is not valid, as generally understood. Matter can be resolved into energy. And this energy is radiated into space, or converted into other modes of energy, and finally into heat, which is in turn radiated into the surrounding medium. The whole universe seems to resemble a clock, which has been wound-up, and is slowly running down. Even the law of the “conservation of energy” has been called into question (See LeBon, “The Evolution of Matter,” and “The Evolution of Forces”). Is the whole Universe in some mysterious manner also being wound-up? Or does it move in vast cycles, of alternate action and inaction, as the Hindu philosophers have always contended? These are ultimate questions which only the science of the future can solve!
PART II
We have now made a rapid survey of the history of chemistry, and traced the evolution of thought which has rendered possible the newer conceptions of the constitution of matter. We must now say a few words as to the nature of the various elements themselves, and give a brief account of some modern researches. A few practical hints as to experiments may also be of interest to the reader.
We have seen that when two chemical elements combine, some third substance is formed, quite different in properties from the original two. Thus, water seems to us entirely different from the two invisible gases which compose it—oxygen and hydrogen. Yet a simple experiment will prove that such is the case. We can decompose water by means of an electric current, when the original gases are given off, in the proportion of two to one—hydrogen collecting at the negative pole, and oxygen at the positive. This process can be kept up until all the water has been decomposed, and only hydrogen and oxygen gases remain. This process of electrical decomposition is known as electrolysis.
THE ELEMENTS
Hydrogen is the lightest of all gases, and, as we have seen, the simplest of the elements, in its constitution. Like all gases, it can be liquefied, and even frozen solid into a hard lump, like ice. On the other hand, even the densest of substances can be liquefied, and even turned into gas or vapor at a sufficiently high temperature. (Gases are rendered liquid or solid at a very low temperature.) Liquid air, for example, is so cold that when a can of it is set upon a block of ice the liquid air boils and gives off “steam”!
Oxygen gas constitutes about one-fifth of our atmospheric air (the other four parts being nitrogen) and is the most essential element in supporting life. Without it, life would at once become extinct. All forms of combustion take place very rapidly in oxygen, and the combustion going on within the human body is no exception to this rule. The atmospheric nitrogen acts as a sort of dilutant, being an inert gas. If a mouse be placed under a jar of pure oxygen gas, it will often run round and round until it drops dead with exhaustion. In an atmosphere of pure oxygen, we should soon burn up, and live our lives too rapidly.