Carbon is combustible and evaporates, when subjected to strong heat, but it never melts.
Carbon mixes with certain liquids, but never dissolves.
Carbon and the diamond crackle in the fire, but never soften.
How then, in the present state of our knowledge, can the transformation of carbon into diamond be eifected ?
It
is self-evident, that to this end is necessary either the discovery of
a new liquid or the concentration of such heat as no chemico-physical
instrument has yet produced.
It
appears that in the formation of the diamond Nature uses heat of an
extremely high temperature, but her power infinitely exceeds that of
man.
In
1828 Cagnard de la Tour sent to the Academy of Sciences at Paris ten
tubes full of small crystals, of a brown colour, which he presented as
crystallized carbon ; after many experiments they proved to be merely
various transparent silicates, harder than quartz, less so than
diamond, and also incombustible.
A
short time after, Gannal tried various experiments with phosphorus and
sulphur; but the trial which appeared most likely to conduce to the
desired end was that of the celebrated Desprez, who hoped to succeed
in melting carbon by uniting all the voltaic piles in Paris, in order
to concentrate the heat to a degree never previously attained, over
pieces of carbon enclosed in a glass receiver. Under this terrible
temperature the carbon evaporated entirely, excepting that
