THEORY OF GALVANISM. 149 



decompositions acted in any way but as conductors, 

 if they gave electricity to the disks, we ought to 

 perceive this electricity when we insulate the pile, 

 and establish a communication for some time be- 

 tween the poles ; but this is not found to be the 

 case. Besides, if chemical affinity were the prin- 

 ciple of the action, it ought to be exercised in the 

 same manner whether the communication was esta- 

 blished or not between the two poles of the pile, 

 since this circumstance has no influence but upon 

 the circulation of the electricity. But we find, on 

 the contrary, that the decompositions are not car- 

 ried on with any degree of energy in the pile, ex- 

 cept the communication be established ; and when 

 it is not so, if we only employ simple saline solu- 

 tions, which are of themselves incapable of attack- 

 ing the metal, we find that there is either no oxida- 

 tion at all produced, or only a partial and extremely 

 feeble one, such as is capable of being produced by 

 the imperfect communication which is established 

 between the two poles of the pile by the mere 

 contact of the molecules of air, which slowly 

 remove the electricity which is developed at its 

 summit." * 



How far the remarks of M. Biot ought to be 

 regarded as containing any valid objections against 

 the chemical hypothesis, or how far the statements 

 upon which he founds his opinions are agreeable to 

 the facts that are the best established, and that 



. 



* Traite de Physique, ii. 537, 



