74 
THE HON. SIR CHARLES ALGERNON PARSONS: EXPERIMENTS ON 
tlie hole (fig. 8) and the shot fired through it, as also through a crucible of carbon 
with a very thin bottom containing a little molten highly carburized iron. 
Of all these experiments the only ones that yielded a reasonable amount of residue 
were one made with graphite wrapped in tissue paper, the bullet, however, in this 
case having grazed the side of the hole, and thus producing some molten iron by the 
friction, as also the shots through the incandescent bridge, where again some molten 
metal would probably occur. The residues were in all cases exceedingly small and 
not more than would be produced from a small amount of iron melted, carburized and 
quickly cooled. There was no evidence of any incipient transformation of carbon in 
bulk into diamond that could be detected by analysis. 
I I 
I I 
k-4 
Fig. 7. 
A bullet was also fired into a long hole, 0‘303-inch in diameter, bored in a steel 
block and filled with acetylene gas, retained by gold-beater’s skin over the mouth, 
thus repeating the flame experiment (but in this case without oxygen) on a small 
scale with the intensest pressures available. The residue was nil. 
The pressure on impact of a steel bullet fired into a hole in a steel block which it 
fits is limited by the coefficient of compressibility of the steel, and with a velocity 
of 5000 ft./secs, is about 2000 tons per sq. inch. Measurements made from a section 
through the block and bullet (fig. 7) showed that the mean retarding force on the 
frontal face, after impact till it had come to rest, was about 600 tons per sq. inch. 
