"ON THE THEORY OF GALVANISM. *f f) 



of the pile, we muit conclude that the zinc plate becomes abfo- 

 lutely negative through its whole fubllance. If the zinc be- 

 came negative only in relation to the quantity of electricity ac- 

 cumulated in the filver, it would follow that the fame effects 

 fhould be produced whether the filver was connected with the 

 negative end of the pile, or with any other metallic fubftance 

 of equal bulk ; but this is directly contrary to fact. Belides a Direction of the 

 variety in the quantity or quality of the electricity, another ma- 

 terial difference between the two ends of the pile is the direc- 

 tion of the current. While the electric matter is difengaged 

 from the oxidating furface, it feems impoffible to imagine that 

 it can be received again by the fame furface from which it has 

 been difcharged, and which is continually difcharging frefh 

 quantities of the fluid. The electricity is therefore neceifarily 

 diffufed through the interpofed liquid, and from this is taken up 

 by the oppofite metallic furface. Upon the uniform direction 

 of its current it is that the action of the apparatus eflentially de- 

 pends ; and accordingly we find that its effects are fufpended 

 when it is altogether furrounded with water, or even when 

 the external edges of the plates are moiftened. It is a very Limit of ele&ri- 

 curious circumftance in the operation of this apparatus, that it zatIon * 

 does not appear capable of having its power augmented by 

 permitting the electricity to become accumulated in it. The 

 oxidating furfaces of the zinc are continually difcharging a large 

 quantity of electricity, all of which is carried forward to the 

 pofitive extremity, and does not appear to efcape from it ; yet 

 after the two ends of the pile have been brought to an equili- 

 brium by means of an uniting conductor, the energy and in- 

 tenfity of the apparatus are inftantaneoufly reftored to as great 

 a degree as before the difcharge. Upon the whole it may be 

 inferred, that though the two extremities of the pile differ from 

 each other in the abfolute quantity of electricity which they 

 contain, yet there is reafon to fuppofe that fome farther altera- 

 tion is effected, which at prefent we are unable to explain. 



4. With refpect to the operation which takes place at the endsEffe£h at the 

 of the wires in the interrupted circuit, whatever idea we may e " ds of thc 



wires* 



adopt of the comparative ftates of the electric fluid in the two 

 extremities of the pile, we can fcarcely doubt that it proceeds 

 from the pofitive to the negative end, or from the wire which 

 emits oxigen to that which emits hidrogen. The oxigen which 

 is difengaged from the pofitive or difcharging wire, muft necef- 



farily 



