THE ARTIFICIAL PRODUCTION OF DIAMOND. 
71 
charge, yet it was thought well to repeat the experiment with rods of iron and 
tungsten imbedded in the core, so that should the temperature of volatilization 
of the metals under a pressure of 12,000 atmospheres exceed that necessary to 
liquefy carbon under the same pressure, the presence of these metals might produce 
a different result. No change however occurred, though in one experiment the 
pressure was raised to 15,000 atmospheres. 
Experiments Designed to Melt Carbon under Pressure by the Rapid Compression 
of Flame. 
A different mode of attack was then arranged, which would ensure that carbon 
should be subjected to an extremely high temperature concurrently with high pressure, 
obtained by the rapid compression of the hottest possible flame, that of acetylene 
and oxygen, with a slight excess of the former to provide the carbon. 
The arrangement was as follows (figs. 4 and 5) :— 
