338 Improved Process for ohtaming Potassimn. 



Art. XVIII. — Improved Process for obtaining Potassium, ; by 

 Robert Hare, M. D., Prof, of Chem. in the Univ. of Penn. 

 Read before the Amer. Philos. Society, Dec. 7, 1838. 



In evolving potassium, agreeably to Brunner's plan, I have sub- 

 stituted for the luting usually employed to protect the iron bottle, 

 a cylinder of iron, which is made to surround the bottle ; also a 

 disk of the same metal, of a diameter and thickness equal to that 

 of the cylinder. 



The disk is supported by bricks of kaolin. The bottle being 

 vertical, the blast acts more equably on the surface of the iron, 

 and the operator can, by additional fuel, protect any part from that 

 undue exposure, to which the under surface is always liable^ 

 when the bottle is horizontal. 



The potassium is received into an iron tube, of which the bore 

 is two inches in diameter. This tube screws at one end into the 

 bottle, and at the other is closed by a perforated plug, terminating 

 in a small orifice. To this a leaden tube is fitted, which is so ad- 

 justed by bending, as to cause the vapor resulting from the burn- 

 ing of the gas, to go into the ash-hole. By these means the hy- 

 drogen, being ignited as soon as it comes over, serves as an index 

 of the success and progress of the process. In this way no resort 

 to naphtha is in the first instance necessary. The potassium is 

 extricated from the tube by cooling it by affusion of water, de- 

 taching it from the bottle, and then closing the end thus exposed 

 by a cap, in which a suitable conical female screw is wrought. 



The part of the tube containing the potassium is then made in 

 a vertical position to occupy the axis of a cylindrical furnace, the 

 end terminating, as above mentioned, in a tapering plug, being 

 lowermost, and projecting below the bottom of the furnace. Be- 

 fore the temperature reaches redness, globules of the metal begin 

 to descend ; but to extricate the last portion, a white heat is requi- 

 site. The potassium may be received in bottles, kept full of hy- 

 drogen by a constant current, or in naphtha. The first portion, 

 which descends before the temperature is high, can be more easily 

 received without naphtha than the latter portion. 



