VOLTAIC BATTERIES. 



A current of electricity will now be established along the wire 

 passing as indicated by the arrows, from the last copper plate atP, 



to the earth at p', and returning by ri to the first zinc plate z v 

 at y. 



This current is produced by the combined voltaic action of all 

 the pairs of plates contained in the cells of the trough. 



37. The current produced by the combination z x c v in the first 

 cell, will flow from the plate c x by the band of metal to the plate 

 Z 2 , in the second cell. It will follow this course because of the 

 conducting power of the metals, and the insulating power of the 

 wood and earthenware, which prevents its escape. From the plate 

 z 2 it will pass through the acidulated water to the plate C 2 , for 

 although this water has not a conducting power equal to that of 

 metal, it has nevertheless sufficient to continue the current to c 2 . 

 From C 2 it will pass by the band of metal to z 3 , and from that 

 through the liquid in the third cell to C 3 , and from that by the 

 metal to Z 3 , and so on until it arrives at the last plate c n of the 

 series, from which it will pass, by the conducting wire, from P to p'. 



It is evident, therefore, that the current produced by the voltaic 

 combination in the first cell must pass successively through the 

 plates and liquid in all the cells before it can arrive at P. 



In the same manner it may be shown that the current produced 

 in the second cell containing z 2 and C 2 must pass through all the 

 succeeding cells before it can reach P, and so of all the others. 



38. !Xow, if the metals and liquid were perfect conductors, each 

 of these currents would arrive at P with undiminished force, and 

 then the current upon the wire P p' would be as many times more 

 intense than a current produced by a single voltaic combination as 

 there are cells. But this is not so. The metals copper and zinc, 

 though good conductors, are not perfect ones, and the acidulated 

 water is a very imperfect one. The consequence is, that the 

 currents severally produced in each of the cells, suffer a consider- 

 able loss of force before they arrive at the conducting wire ?p'\ and 

 mathematical formulae, based on theoretical principles and practical 

 data, have been contrived to express in each case the effects of this 



K 2 131 



