178 HISTORY OF CHEMISTRY. 



cles, in the other on masses ; . . . and that the same 

 property, under different modifications, was the 

 cause of all the phenomena exhibited by different 

 voltaic combinations!' 



Although this is the enunciation, in tolerably 

 precise terms, of the great discovery of this epoch, 

 it was, at the period ofwhich we speak, conjectured 

 rather than proved ; and we shall find that neither 

 Davy nor his followers, for a considerable period, 

 apprehended it with that distinctness which makes 

 a discovery complete. But in a very short time 

 afterwards, Davy drew great additional notice to 

 his researches by effecting, in pursuance, as it ap- 

 peared, of his theoretical views, the decomposition 

 of potassa into a metallic base and oxygen. This 

 was, as he truly said, in the memorandum written 

 in his journal at the instant, "a capital experiment." 

 This discovery was soon followed by that of the 

 decomposition of soda ; and shortly after, of other 

 bodies of the same kind; and the interest and 

 activity of the whole chemical world were turned 

 to the subject in an intense degree. 



At this period, there might be noticed three 

 great branches of speculation on this subject; the 

 theory of the pile, the theory of electrical decompo- 

 sition, and the theory of the identity of chemical 

 and electrical forces ; which last doctrine, however, 

 was found to include the other two, as might have 

 been anticipated from the time of its first suggestion. 



