view, and recognized octahedrons, both black and white, the black being truncated at their extremities.
In
another experiment M. Despretz fixed a cylinder of pure carbon to the
positive pole of a weak Daniell pile, and a platina wire to the other
pole; he then plunged both poles into slightly acidulated water. The
experiment lasted two months; the negative wire or pole became covered
with a black coating, but nothing was discovered in it under the
microscope.
The
products of the experiments were then sent to M. Gaudin to test upon
hard stones. He proved, in the presence of M. Despretz and others,
that, mixed with a little oil, the substance which had enveloped one of
the twelve platina wires sufficed to polish in a very little time
several rubies. The black powder deposited in the water served to give
similar polish, but it required longer time. As it is known that the
diamond is the only substance that polishes the ruby, M. Gaudin did not
hesitate to consider both these substances as the powder of the diamond.
Two
conclusions may be derived from the facts we have just stated: 1st,
that it is probable that the diamond is not of igneous origin; 2d, that
M. Despretz has really obtained artificially the true diamond. This is
the opinion of men of the
