12 



The Hon. Sir Charles Parsons 



[Jan. 23, 



introduced ; lastly, a layer of graphite is placed on the top and the 

 whole pressed to the desired pressure for the experiment. 



[none experiment several pounds of carbon dioxide snow were 

 added to the charge, which consisted of magnesia, and was so 

 arranged thai evaporation of the heating carbon rod took place in 

 an atmosphere of carbon dioxide and carbon monoxide under a 

 ius pressure of 4400 atmospheres, the condensate resulting 

 being soft graphite. Upwards of 200 chemical reactions arranged 

 to deposit carbon were tested under high pressure and central 

 heating. After each experiment samples were taken from various 

 parts of the charge and carefully analysed for diamond, the methods 

 of the analyses generally following those of Moissan and Crookes. 

 Very small residues of diamond occasionally occurred, but they 



MUZZLE OF .303" RIFLE 





WW — 



V/^V//* Graphite 



Fig. 7. 



appeared to be associated with the presence of iron in the charge, 

 whether introduced intentionally or from the melting of the pole 

 pieces, short circuits, or from other causes. On the whole there was 

 do evidence that diamond had been produced by any of the chemical 

 reactions, some of which were endothermic, such as carborundum 

 and sodium carbonate, which produced a grey solid which detonated 

 when struck with a hammer, and nearly caused a serious accident. 

 In one experiment the charge was olivine and water; when molten 

 under 10 tons per square inch, the pressure was suddenly removed 

 and artificial pumice was formed by the expansion of water vapour 

 absorbed by the olivine when molten. Having nearly reached the 

 limits iA' steady pressure obtainable in steel containers under a press, 

 experiments with impact pressures produced by steel bullets were 



