The Romance of Modern Chemistry

NATURAL WATERS abundant, but because it is so absolutely essential to life of all kinds. From the chemist’s point of view, water ia an ex- ceptionally interesting substance. For, in the first place, it furnishes an excellent example of the thorough-going alteration which matter may undergo when it takes part in chemical processes. Think of it. Hydrogen and oxygen, the elements which combine chemically to form water, are gaseous, invisible substances which we may mix without any obvious change taking place. In the mixture neither gas interferes with the other, and each retains its own characteristics and properties. But bring a lighted taper or match near the mouth of the vessel which contains the gases, and what is the result ? The gases, which have up to this point been in peace- ful contact, are stimulated to mortal combat, a loud explosion occurs, and the gases are destroyed, leaving behind only the sweat of battle in the shape of a few drops of water. One has seen a conjurer converting handkerchiefs into rabbits, and a pack of cards into thin air, but his feats are tricks after all, and the more genuine cause of wonder is to be found in the marvel- lous things which Nature has to show. Among these marvels are such changes as that by which hydrogen and oxygen are converted into water, a substance with absolutely new properties and characteristics. Water, however, is interesting in other ways. Has the reader ever observed that ice floats in water ? He may have seen it, but not perceived it Probably the fact has just been accepted as a matter of course, without any inkling of its importance. But the truth is that water is somewhat eccentric in this respect. Generally speaking, when any substance is exposed to lower and