THE ARTIFICIAL PRODUCTION OF DIAMOND. 



81 



It is probable that some meteoric matter may have been melted by collision or 

 ejected into space in a molten state and cooled by radiation, and that under such 

 conditions the absence, or diminution, of occluded gases might be a factor conducive 

 to the crystallization of carbon. 



One of the 4-inch diameter pressure moulds (fig. 10) was used in a preliminary 

 experiment as the container. The crucible was turned out of a 1^-inch carbon rod, 

 and so formed on a stem that the electric current heated the bottom and sides 

 equally. The cover was similarly formed and its holder was electrically connected 

 with the container, but free to move vertically and to rest its weight on the crucible, 



"Ram 



Rubber 

 joint 



Brass 

 chips 



Preaspalm 

 insulation 



Fig. 10. 



electrical connection to the container being made by a layer of brass or iron turnings 

 resting on the holder. A current of 1000 amperes at 16 volts sufficed, and the 

 temperature was observed through a glass window at the side of the container. 



The crucible was charged with reduced iron and lampblack. The Geryk pump 

 evacuated the container to f-inch mercury absolute ; current was turned on for 

 15 seconds, the vacuum fell to 3 inches, when it had risen again to |-inch current 

 again turned on. This was repeated three or four times, finally current was 

 applied for 30 seconds and the vacuum again fell to 3 inches. The gas was drawn 

 off and collected, it amounted to a total of gallon at atmospheric pressure and 



