HISTORY OF GALVANISM. 39 



considered as having shown that the galvanic influ- 

 ence depends upon some modification of electricity, 

 yet the complete identity of the two agents could 

 scarcely be considered as fully proved, until the 

 most remarkable effects of the pile had been imi- 

 tated by the action of the machine. Dr. Wollas- 

 ton's view of the subject has been considered as 

 combining, to a certain extent, the theory of Volta 

 with that of Fabroni ; according to the literal ac- 

 ceptation of the terms, however, it must be re- , 

 garded as favouring the chemical hypothesis, be- 

 cause it contemplates a chemical change as the 

 primary step in the operation, from which all the 

 subsequent effects are ultimately derived. 



A set of experiments was performed about this De&orme' 

 period by Desormes, the object of which was to "cuts"" 

 ascertain the source of the oxygen which com- 

 bines with the plates ; this he conceives did not 

 depend upon the actual decomposition of the 

 water, but upon some change which the water 

 experiences by the union of the negative and po- 

 sitive electricity. The same reasoning was of 

 course applied to the hydrogen, and a similar 

 opinion has been since adopted by other philoso- 

 phers, but it has generally been regarded as a less 

 simple method for accounting for the facts, and as 

 involving more gratuitous suppositions.* 



Professor Trommsdorff discovered that the pile Tromms- 



rt i i dorff burns 



possesses a very powerful effect in burning me- metallic 



leaves. 

 * Ann. de Chim. xxxvii. 284. 



