1920] on Researches at High Pressures and Temperatures 11 



Note. — The temperature at which carbon, iron or tungsten vola- 

 tilizes under a pressure of 15,000 atmospheres are unknown, but they 

 are probably much higher than at atmospheric pressure. 



This experiment also tested iron as a solvent of carbon, and as a 

 calylist from diamond to graphite under a pressure of 100 tons, and 

 showed that under this pressure that action was not reversed. 



Fig. 6 shows the container arranged for treating powders by 

 resistance heating with or without the addition cf liquids or gases. 



The electric current is conveyed from the container to the upper 



PAPER TUBE 



CHARGE 



ASBESTOS ^ 

 MICA INSULATION 



K4AGNESITE 



Rubber cup 



PACK IMG 



VULCANIZED 

 FIBRE RING 



Fig. 6. 



end of the conductor by a layer of graphite which rests on the charge 

 under treatment. The bottom end of the conductor rests on or is 

 spigoted into a cast-iron block which rests on the bottom pole ; this 

 block is sometimes partially melted, but can be easily renewed. 

 The container is charged by first stemming magnesite powder by 

 hand around the bottom pole piece and block ; then the charge is 

 placed on the top and pressed to 5 tons per square inch ; the top ram 

 is then removed and a hole drilled through the charge and the con- 

 tainer inserted ; liquids if used, or carbon dioxide snow, may then be 



