6o HER OES OF INVENTION AND DISCO VER V. 



nitrogen, an opinion generally prevailed that hydrogen would 

 be found to be also a chief ingredient of the Jixed alkalis. 

 Davy determined, if possible, to ascertain this point, and 

 engaged in the investigation with great hopes of success, from 

 the surpassing powers of decomposition which he had found to 

 belong to his new agent, the galvanic influence. The manner 

 in which he pursued this object is one of the most beautiful 

 specimens of scientific investigation on record. One of the 

 most important of the laws of galvanic decomposition, which 

 he had previously discovered, was that, when any substance 

 was subjected to this species of action, its oxygen (an ingredient 

 which nearly all substances contain) was developed at what is 

 called the positive end or pole of the current of electricity, 

 while, whenever any hydrogen or inflammable matter was 

 present, it uniformly appeared at the opposite or negative pole. 

 Proceeding upon this principle, therefore, Davy set to work with 

 a fixed alkali ; and at first submitted it dissolved in water to 

 the galvanic action. The result, however, was, that the water 

 alone was decomposed, nothing being disengaged by the experi- 

 ment but oxygen and hydrogen, the ingredients of that fluid, 

 which passed off as usual, the former at the positive, the latter 

 at the negative pole. In his subsequent experiments, therefore, 

 Davy proceeded without water, employing potash in a state of 

 fusion; and, having guarded the process from every other 

 disturbing cause that presented itself, by a variety oi ingenious 

 arrangements, he had at last the satisfaction of seeing the 

 oxygen gas developed, as before, at the positively electrified 

 surface of the alkali, while at the same time, on the other side, 

 small globules of matter were disengaged, having all the 

 appearances of a metal. The long-agitated question was now 

 determined ; the base ol the fixed alkalis was clearly metallic. 



