Chap, in.] OHM'S LAU\ 29 



The second method is shown in Fig. 1 6. The positive 

 pole of one cell is joined to the negative pole of the 

 other, and so on through the set of cells. This leaves 

 vacant the negative pole of the first cell and the 

 positive pole of the last, and wires joined to these are 

 the electrodes of the battery. 



In this case each cell has its i(?X*X5KsHX2)- 

 own electromotive force and F ig. iG.-Mode of joining 

 resistance unaffected, so that the Cells in "Series." 

 total electromotive force of the 



battery is the sum of the electromotive forces of the 

 several cells forming it, and the total resistance of the 

 battery is the sum of the resistances of the several 

 cells. Thus, 



6E E 



6R R' 



Thus, apparently, no advantage as regards quantity 

 of current is obtained by joining in series. Let us 

 now include both internal and external resistances, 

 and see under what circumstances one or other 

 method is preferable. 

 Take Ohm's formula, 



C- E 

 R+V 



as a basis, and let us first consider the results of 

 joining cells in " multiple arc," 



1. Suppose six cells to be connected by a thick 

 wire to some apparatus that presents little resistance ; 

 that is to say, let the external resistance be so small 

 in comparison to the internal that it may be set aside. 

 r may be considered as equal to o ; then, the cells 

 being joined in multiple arc, 



~ J , ~ 6E 



C = - - ; but r = o, .-. C = - , 



is, the current is six times as great. 



