on the Experiments of Folta. 30;? 



which would be eftabliflied between them at the moment of 

 conta(5l. 



What we have faid extends alfo to all other bodies between 

 which there may exift an analogous action : thus, though 

 this action niav appear in general very weak between liquid 

 and metallic fubftances, there are however fome, fuch as the 

 alkaline fulphurets, the a6lion of which with the metals be- 

 comes very fenfible : the EngliHi chemifts, therefore, have 

 been able to fupply by thefe fulphurets one of the metallic 

 elements of the pile; and before them profeflbr Pfaff, of 

 Kiel, employed llicm for this purpofe in his experiments. 



In this refpeft, C. Volta has difcovered between the me- 

 tallic fubdances a very remarkable relation, which renders it 

 iniponiblc to conllruft a pile with thefe fubftances a'one. We 

 fliall here explain them according to his account, but we 

 have had no opportunity of confirming them. 



If the metals be arranged in the following order — filver, 

 copper, iron, tin, lead, zinc, — each of them will become po- 

 fitive bv the contact of that which precedes it, and negative 

 with that which follows it : the ele6lricity will pafs then from 

 the filver to the copper, from the copper to the iron, from 

 the iron to the tin ; and fo on. 



Now the property in quefiion confifts in this, that the 

 moving force of the filver to the zinc is equal to the moving 

 forces of the metals coniprehended betweeii them in the fe- 

 ries : hence it follows that, bv placing them in contaA in this 

 order, or in anv other at plcafure, the extreme metals will be 

 always in the fame Hale as if they inmiedialely touched each 

 other; and confeqiicntlv, fuppofing any number of elements 

 whatever thus difpofed, and of which the extremities are for 

 example filver and zinc, we fhall have the fame refult as if 

 thefe elements were formed of thefe two metals; that is to 

 fay, there will be no effecl, or it will be that which would 

 have lieen produced by one element. 



It has hitherto app.earcd that the prccedino; property ex- 

 tends to all folid bodies, but it does not fubfill between them 

 and the liquids: hence it happens that a pile may be con- 

 Itructed by the medium f)f the latter. From this refults the 

 divifion which Volta makes of conductors into two clafils; 

 the firft comprehending folid bodies, and th'e fecond liquids. 



It has not yet been poflible to con(lru6l a pile but by a 

 proper mixture of thefe two clafles : it cannot be done with 

 the firtl alone, and we are not ytt fufficiently acquainted 

 vviih the mutual aiStion of the bodies which compofe the fe- 

 cond, to deleruiiiic whelher the cafe is the lame in regard to 



lliCUl. 



U a We 



