ARTIFICIAL PRODUCTION. 231
The
latest experiments in the reproduction of crystals, and particularly of
precious stones, have been made by MM. Deville and Caron. The method
employed by these chemists is founded upon the same principle as those
of Daubree and Durocher; but the agencies employed by them are
incomparably more powerful, and the results which they have obtained
more brilliant.
With
the enormous temperature developed by the furnaces of Deville and Caron
ordinary crucibles could not be used: they melted like lead. The
crucibles which they used were made of lime. Anybody can make them, and
they are absolutely fireproof.
Among
the principal results obtained by the experiments of these chemists
were crystals of white corundum, rubies, and sapphires.
The
crystals of corundum, nearly two-fifths of an inch in length, exhibited
all the crystallographic and optical properties of the natural
corundum. The rubies, obtained very nearly in the same way, had the
violet-red tint of the natural ruby conveyed to them by the oxide of
chromium, which furnished also, in a different proportion, the blue of
the sapphires. Sometimes, in the experiments of Deville and Caron, red
rubies and sapphires of the most beautiful blue were obtained side by side.
A similar experiment produced specimens of
