208 
PROCEEDINGS OF THE NATURAL [APRIL, ’89. 
Dr. Hopkmson reports that they used 60 volts to keep 
the cryolite in a state of fusion and electrolyse the salt. 
I cannot at present refer to details of work on the obtain¬ 
ing of pure salts of A1 as electrolytes, and of durable 
crucibles, free from Fe and Si, besides mechanical arrange- 
ments and devices. 
