G8 



THE HON. SIR CHAKLES ALGERNON PARSONS: EXPERIMENTS ON 



up to 15,000 atmospheres, which produced soft graphite, and an experiment where a 

 carbon crucible, containing iron previously heated and carburized in the electric 

 furnace, was quickly transferred to a steel die, and while molten and during cooling 

 subjected to a pressure of 11,200 atmospheres, the analyses showing less crystalline 

 residue than if the crucible had been cooled in water. 



It was also emphasized that the pressure of 11,200 atmospheres must be greater 

 than could be produced in the interior of a spheroidal mass of cast iron when 

 suddenly cooled, and that the inference from these experiments was that mechanical 

 pressure is not the cause of the production of diamond in rapidly cooled iron, as had been 



Thin 



presspahn 

 insulation 



Brass & 



leather 



cup 



packing 



Rubber 

 cup 

 ring 



Vulcanized 

 fibre 

 ring 



Fig. 1. 



supposed by MOISSAN. This conclusion appears to us in the light of our more recent 

 experiments to be one of great importance, and it will be further discussed in this paper. 

 It may be well to state that, in order to facilitate a clearer view of the bearing of 

 each experiment on the subject, they are not placed always in chronological order. 

 The difficulty of ensuring satisfactory experiments and the elusive character of the 

 analyses must be the excuse for the random character of some of the former. The 

 great majority of the experiments were failures as regards results, but a few have 

 given information that was scarcely anticipated when they were devised. 



