40 On the Hi/polheses nf Galvanism. [Jan. 



acknowledged tiifnculty in this hypothesis to explain the reason why 

 saline fluids are more powerful in their operation than pure water. 

 Volta's method of re})]ying to it, tliat saline fluids act better only 

 so far as they are better conductors,* has generally been thought 

 unsatisfactory, and yet no other has been substituted in it« place. 

 That it should be still persevered in seems the more remarkable, 

 because Sir H. Davy, in an early stage of the investigation, clearly 

 stated that the action of the different fluids was not in proportion to 

 their conducting power. + Indeed, when we consider how readily 

 pure water transmits the electric fluid, we can scarcely attribute to 

 a deficiency in its conducting power the comparatively small effect 

 which it produces in tlie pile, nor to a mere increase of this con- 

 ducting power, the vastly greater activity of diluted acids or neutral 

 Kilts. But independently of all considerations of this nature, it 

 v.'ould appear, from referring to the principles of the hypothesis, 

 that the more we increase the conducting power of the fluids, the 

 less should be the action of the pile. The contact of the metals 

 destroys the electrical equilibrium ; and, according to Volta, the 

 only effect of the interposed fluid is to counteract this disturbance, 

 and to restore the equilibrium ; it nnist then obviously follow that 

 the more perfect the conductor, the more completely will the 

 equilibrium be restored, and therefore the less effect will be pro- 

 duced by its destruction. The same kind of argument, but with 

 pome modification, may also be urged against Sir H. Davy's peculiar 

 hypothesis; for whether we suppose the effect of the fluid in 

 restoring the equilibrium to depend upon its conducting power, or 

 upon its tendency to decomposition, it v^ill follow, that the better 

 it conducts, or the more readily it is decomposed, the less will be 

 tlie efl'eci of tlie apparatus; this conclusion is, however, directly at 

 variance with the fact. 



3. According to the electrical hypothesis, under every one of Its 

 modifications, it is necessary to suppose that a current of electricity 

 exists whicli constantly passes from the first copper ])late to tlie 

 i'ontrary end of tlic pile; and, indeed, it is expressly stated by 

 Volta himself, that this current constitutes the essential part of its 

 operation. J Yet we know that the action of the pile is very con- 

 siderable before its extremities are united ; and what, in this case, 

 are we to conceive lespecting tl'.e current? Whence does it pro- 

 ceed, and where does it terminate? The supposition that a current 

 must exist at a time wlien the ends of th.e pile are not in a situation 

 for either giving or receiving electricity, seems almost decisive 

 against the hypothesis ; and it is remarkable, that many of the 

 writers upon the su])ject5 not excepting Volta himself, § in opjwsi- 

 tion to the clearest evidence of facts, have asserted, or insinuatedj, 

 that the apparatus does not act until its extremities are united. 



•> \ich. Jour. ). ISO. 



t Nicli. Jour. iii. 135. Sec also his later experiments, Phil. Tians, 1807. 



% Fiiil. Trans. 1800, &c. 



ij JSich. Jour. i. 135. See also De Luc, in Nich. ixvi. 115, &c. 



