The Romance of Modern Chemistry

HOW MAN COMPETES WITH NATURE with natural camphor in all ordinary physical and chemical properties, and provided that a plentiful supply of turpentine at a moderate price is available, the next few years may witness a repetition of what has already occurred in the cases of alizarin and indigo. It is a very confusing circumstance that there is also on the market a product known as “ artificial camphor,” which, indeed, has an odour resembling that of true camphor, but which is chemically quite a different sub- stance. Synthetic camphor, on the other hand, is chemi- cally identical with the natural product. Another and quite different direction in which we have been trying with success to imitate Nature is in the manufacture of rubies. In an earlier part of this volume it was stated that Moissan had been able to produce real diamonds, so small, however, as to be of no ornamental value. The specimens commonly known as “artificial diamonds” are spurious; the “paste” used in their manufacture is chemically quite different from the dia- mond, which, as the reader knows, is simply crystallised carbon. Artificial rubies, however, are chemically identi- cal with the natural gems, and are indistinguishable from them. Rubies and sapphires are practically pure alumina in the crystallised condition; they consist almost entirely of this compound of aluminium and oxygen. Alumina itself is a colourless substance, and the colours of the natural stones are due to the presence of small quantities of the oxides of chromium and iron. If the crystallised alumina is free from these other materials, we have the mineral known as corundum, which in hardness is second only to the diamond, and with which, in an impure form, we are familiar as emery. So that the useful and the 257 a