hard glass vessel was used); the final result was washed into a shallow watch-glass and the selection made under the microscope.
"
From the treatment they have" undergone, chemists will agree with me
that diamonds only could stand such an ordeal ; on submitting them to
skilled crystallographic authorities my opinion is confirmed."
Another method, evidently new, is put forward by Mr. C. V. Burton, of Cambridge. This gentleman, writing in Nature,1 states
that lead containing about 1 per cent, of calcium is capable of holding
a certain amount of carbon in solution either in the free state or as
calcium carbide. This carbon crystallises out in the form of minute
octahedral crystals, having all the properties of the Diamond if the
calcium be eliminated. To get rid of the calcium, or rather to render
it inert, he passes steam through the molten mass, converting it by
this means into calcium hydrate. The lead is unaffected, and at a dull
red heat the carbon crystallises out as above, but if at a full red
heat only Graphite is obtained.
Besides
the above experiment, Mr. Burton has been successful in the reduction
of carbon compounds, such as benzene, toluene, carbon tetrachloride,
etc., in sealed tubes and bombs, at temperatures of 200° C. and 300° C.
In
1898, J. Friedlander produced some smoky crystals having all the
properties of the Diamond by fusing the mineral Olivine (an iron
silicate of magnesia) in a gas blowpipe, the fusion being stirred
frequently with a stick of pure Graphite ; after cooling this was found
to be encrusted with exceedingly small crystals of Diamond.
1 " Artificial Diamonds," Nature, p. 397, Vol. 72, August 24, 1905.
