244 ALKALIES- 



2. PROCESS. 



DECOMPOSITION OF POTASH AND SODA. 



1. By galvanism. The first attempts of Sir H. Davy were made 

 upon aqueous solutions of potash and soda, but the water alone was 

 decomposed. He then kept the potash in perfect fusion by an in- 

 genious contrivance ; it was contained in a spoon of platinum, which 

 was, in the first instance, connected with the positive side of a battery 

 of one hundred pairs of six inches, highly charged, and the connexion 

 from the negative side was made by means of a wire of platinum. 

 A most intense light was exhibited, at the negative wire, and a 

 column of flame arose from the point of contact. When the spoon 

 was made negative, and the wire positive, a vivid and constant light 

 appeared at its point, and aeriform globules which inflamed in the at- 

 mosphere rose through the potash. 



A small piece of pure potash, slightly moistened by the air, so as 

 to give it conducting power, was placed on an insulated disc of pla- 

 tinum, connected with the negative side of the battery of the power 

 of 250 pairs of 6 and 4 inches, in a state of intense activity and a 

 platinum wire, communicating with the positive side, was brought in 

 contact with the upper surface of the alkali. The whole apparatus 

 was in the open atmosphere. 



There was a fusion of the potash at both surfaces a violent ef- 

 fervescence at the upper, and at the lower, i small globules, having a 

 high metallic lustre, and being precisely similar, in visible characters, 

 to quicksilver, appeared, some of which burnt with explosion and 

 bright flame, as soon as they were formed, and others remained and 

 were merely tarnished and finally covered by a white film which 

 formed on their surfaces. 



These globules were the basis of the potash ; they did not pro- 

 ceed from the platinum, for they appeared equally, whether copper, 

 silver, gold, plumbago, or even charcoal, was employed for com- 

 pleting the circuit. The air had no agency in producing the glo- 

 bules, for, they were evolved when the alkali was placed in a 

 vacuum.* 



The substance was likewise produced from potash, fused by 

 means of a lamp, in glass tubes, confined over mercury, and furnish- 

 ed with hermetically inserted platinum wires, by which the electrical 

 action was transmitted. But the glass was so rapidly decomposed 

 by the substance that the operation could not be carried far. 



The substance produced from potash remained fluid at the tem- 

 perature of the atmosphere, at the time of its production. 



* I repeated these experiments in 1S10, and then obtained the metalloids ; see 

 Bruce's Journal. Dr. (now Pres.) Cooper first decomposed pota?h in this country 

 by the gun barrel and furnace. 



