communicated
to the Royal Society, Sir Andrew Noble, exploding cordite in closed
vessels, has obtained a pressure of 8,000 atmospheres, or 50 tons per
square inch, with a temperature reaching in all probability 5,400°
absolute.
"
Here, then, we have conditions favourable for the liquefaction of
carbon, and were the time of explosion sufficient to allow the
reactions to take place, we should certainly expect to get the liquid
carbon to solidify in the crystalline state.
"By
the kindness of Sir Andrew Noble I have been enabled to work ivpon some
of the residues obtained in closed vessels after explosions, and I have
submitted them to the same treatment that the granulated iron had gone
through. After weeks of patient toil I removed the amorphous carbon,
the graphite, the silica, and other constituents of the ash of cordite,
and obtained a residue among which, under the microscope, crystalline
particles could be distinguished. Some of these particles, from their
crystalline appearance and double refraction, were silicon carbide ;
others were probably diamonds. The whole residue was dried and fused at
a good red heat in an excess of potassium bifluoride, to which was
added during fusion 5 per cent, of nitre. (Previous experiments had
shown me that this mixture readily attacked and dissolved silicon
carbide; unfortunately it also attacks diamond to a slight degree.)
The residue, after thorough washing and then heating in fuming
sulphuric acid, was washed, dried, and the largest crystalline
particles picked out and mounted. All the operations of washing and
acid treatment were performed in a large platinum crucible by
decantation (except the preliminary attack with nitric acid and
potassium chlorate, when a
