The Romance of Modern Chemistry

HOW MAN COMPETES WITH NATURE from the simple carbon, hydrogen, oxygen, and nitrogen to the organic compound carbamide. Wohler’s wonderful discovery was interesting not only because carbamide was the first organic compound to be prepared in the laboratory from inorganic materials, but also because it consists of the same elements as are present in ammonium cyanate, and, more than that, the carbon, hydrogen, oxygen, and nitrogen are present in exactly the same proportions in the two compounds. The extra- ordinary fact that two chemical compounds which are quite distinct in external appearance and behaviour may contain the same elements united in the same proportions was very puzzling to chemists at that time, although nowadays it is taken quite as a matter of course. Later workers have shown that such differences are due to a very subtle distinction in the way in which the atoms are arranged in the molecules; the internal anatomy of the molecule is different in the two cases. Since that red-letter day in 1828 synthetic chemistry has made gigantic strides, and we have learned to produce artificially hundreds of naturally occurring products. In many cases such an imitation of Nature has very little interest for anybody outside of a chemical laboratory, but, on the other hand, the synthetic product does occasionally come into the market as a competitor of the natural substance. An interesting example of this is furnished by the history of alizarin. For centuries this valuable dye-stuff was obtained from the madder root, and large areas of France, Holland, Italy, and Turkey were given over to the growth of the plant. Cloth dyed with alizarin has been found on Egyptian mummies, so that its use goes back to a remote age. Yet within the short space of forty years this 253