separate
the calcium he introduced steam into the fused mass, whereby part of
the carbon crystallized. It is said that if the alloy is in a state of
ignition when the steam is introduced, graphite crystals are formed,
but if at a lower temperature, diamond crystals. The crystals obtained
by Dr. Burton are said to possess an unusually high power of
refraction. These experiments have strengthened the belief of some that
Nature used some solvent for carbon, as yet unknown, which by
evaporation left part of the carbon in the crystallized form, as the
crystals of other minerals are.
Hasslinger
and others claimed to have obtained microscopic diamonds from carbon
dissolved in molten silicates, which crystallized as the mass cooled.
The
conditions under which diamonds were found prior to the African
discoveries afforded no clue to their origin. In Africa it is evident
that they are of subterranean origin, though a full consideration of
the conditions there suggests the possibility that diamonds were not
always produced by exactly the same methods, or if so, that they were
crystallized under somewhat varying conditions and were forced to the
surface in material which, if the original matrix, has since passed
through a process of alteration.
As
scientific experiments have demonstrated that the various forms of
crystallized carbon can be produced artificially by a combination of
heat and pressure, and we find in Nature that they come from volcanic
sources, also that they exist, in form identical with the terrestrial
crystals, in meteorites, which are fused masses, heat and pressure
appear to have been present in the laboratory of Nature during their production, though the experiments
