120 THEORY OF GALVANISM. 



be stated, as a general principle, that whatever 

 promotes the action of the fluid upon one of the 

 metals increases the energy of the instrument, and 

 whatever tends to prevent or destroy this action 

 suspends the energy. When considered in this 

 point of view, the experiments of De Luc, on the 

 dissection of the pile, seem to be strongly adverse 

 to the electric hypothesis. In the second distribu- 

 tion of the ternary groups, the two metals are in 

 contact, and therefore any electrical effect might 

 be produced, which would arise from this circum- 

 stance ; there was also the fluid between them, 

 which would serve as a conductor of electricity ; 

 yet because the apparatus was so arranged that 

 this fluid could not act upon the zinc and oxidate 

 it, no proper galvanic effect ensued. 



It is a little remarkable, that notwithstanding 

 the weight of authority to prove that the action of 

 the pile is suspended in vacuo, or in any gas which 

 does not contain oxygen, unless the fluid between 

 the plates contain some saline matter,* Volta, even 

 in a comparatively late period of the inquiry, still 

 continued to deny the fact.f And the same re- 

 mark may apply to what this philosopher says 

 respecting the superior efficacy of saline fluids, 

 which, notwithstanding the experiments of Davy 

 and others, he still perseveres in ascribing simply to 

 their superior conducting power.* And, indeed, 



* Davy, Biot, Van Marum, Pepys, Haldane, &c. 

 f Ann. de Chim. xlii. 281. 

 Nicholson's Journ. 8vo. i. 239. 



