the Decomposition of the Earths, &c. 207 



ness occurred, which various trials demonstrated, depended 

 upon the presence of silex. 



A similar mixture of potash and alumine was experi- 

 mented upon in the same manner, and the results were per- 

 fectly analogous ; there adhered to the rod of platina a film 

 of a metallic substance, which rapidly decomposed water, 

 and afforded a solution which deposited alumine by the ac- 

 tion of an acid. 



I tried several forms of this experiment, with the hopes of 

 being able to obtain a sufficient quantity of the metallic mat- 

 ter from the platina, so as to examine it in a separate state j 

 but I was not successful. It was always in superficial scales, 

 which oxidated, becoming white and alkaline, before it could 

 be detached in the air ; it instantly burnt when heated, and 

 could not be fused under naphtha or oil. 



I tried similar experiments with mixtures of soda and 

 alumine, and soda and zircono, and used iron as the nega- 

 tively electrified metal. In all these cases, during the whole 

 process of electrization, abundance of globules, which swam 

 in a state of inflammation on the fused mass, were produ- 

 ced. And in the mixture, when cooled, small laminae of 

 metal were found of the colour of lead, and less fusible than 

 sodium, which adhered to the iron; they acted violently 

 upon water, and produced soda and a white powder, but ia; 

 quantities too small to be minutely examined. 



I endeavoured to procure an alloy of potassium, and th« 

 bases of the earths, from mixtures of potash, silex, and 

 alumine, fused by electricity, and acted on by the positive 

 and negative surfaces in the same manner as pure potash, 

 in experiments for the decomposition of that substance; but 

 I obtained no good results. When the earths were in quan- 

 tities equal to one-fourth or one- fifth of the alkali, they 

 rendered it so highly non-conducting, that it was not easy 

 to effect it by electricity ; and when they were in very minute 

 portions, the substance produced had the characters of pure 

 potassium. 



I heated small globules of potassium, in contact with silex. 

 and alumine, in tubes of plate glass filled with the vapour oft 

 naphtha : the potassium seemed to act at the same tirpe> 



upon 



