76 HISTORY OF GALVANISM. 



negative wire, while oxygen was produced or 

 evolved by the positive termination. That this 

 was the case with the alkalies, was not only 

 rendered probable by the result of the process, 

 but was afterwards proved by subsequent experi- 

 ments. " When solid potash or soda, in its con- 

 ducting state, was included in glass tubes, fur- 

 nished with electrified platina wires, the new 

 substances were generated at the negative sur- 

 faces ; the gas given out at the other surface, 

 proved by the most delicate examination, to be pure 

 oxygen ; and unless an excess of water was pre- 

 sent, no gas was evolved from the negative 

 surface." 

 Recompo- The experiments by synthesis confirmed the 



sition of . 



theaika- results of those by analysis. The new metallic 

 bodies were converted into potash, by exposure to 

 the air, and it was found that this depended upon 

 the oxygenous part of it. When the globules 

 were placed in contact with oxygen, they com- 

 bined with it, and were covered with an alkaline 

 crust. Sir H. Davy observes very justly, " that 

 in these facts there is the same evidence for the 

 decomposition of potash and soda into oxygen and 

 two peculiar substances, as there is for the decom- 

 position of sulphuric and phosphoric acids and the 

 metallic oxides into oxygen and their respective 

 combustible bases." The two components of the 

 alkalies obey the general law which was laid down 

 in the former paper ; the metallic or combustible 

 base is attracted by the negative extremity of the 

 6 



