852 THE KOYAL INSTITUTION. [CHAP. VI. 



* But although the two fixed alkalies called soda and 

 potash were attacked by the most eminent chemists with 

 every known chemical agent and by every method which the 

 improved state of science could suggest, not the smallest effect 

 could be produced on them ; so that the nature of these two 

 common substances remained totally unascertained and 

 became a grand desideratum of chemical science. When, 

 however, M. Volta had communicated to the Royal Society 

 his great discovery of the galvanic pile, and when this had 

 been modified into the more convenient form of troughs by 

 Crookshank of Woolwich, the electro-galvanic power was 

 found by various philosophers to produce surprising effects 

 when applied to different substances, and Mr. Davy in par- 

 ticular distinguished himself in these researches and made 

 a number of valuable experiments and observations, some 

 of the more remarkable of which he communicated to the 

 Royal Society in the Bakerian lecture read in November 

 1806. Mr. Davy conceived, however, from what he had 

 then accomplished, that much more might be done ; and 

 with equal skill and perseverance he performed a new 

 series of experiments, in the course of which, by various 

 means, he again tried the effect of the powerful galvanic 

 batteries belonging to the laboratory of the Royal Institu- 

 tion, and particularly devoted his attention to the two fixed 

 alkalies (soda and potash), with the view of effecting their 

 decomposition and of ascertaining the nature of them by 

 means of that powerful agent galvanism. 



' This great discovery he at length effected ; and, to the 

 high gratification of all men of science, he proved that 

 soda and potash are compound bodies, each consisting of 

 a peculiar metal, which has so great a tendency to combine 

 with oxygen that no agent but galvanism can separate them. 

 The two metals, therefore, of soda and potash have always 

 hitherto been presented to us in this state of combination 

 with oxygen, forming the two alkalies. But some of the 

 primitive earths (as they are called), such as barytes and 



