292 M. De la Rive's Researches 



number of its pairs may be increased. What will be the re- 

 sult of these species of augmentation in theory and in practice? 

 We proceed to inquire. 



Experiment teaches us that if the number of the pairs re- 

 main constant, the tension of the pile is not increased in a 

 sensible manner by increasing their surfaces, and that the 

 dynamic effects are increased in proportion as those effects 

 are produced by better conductors placed between the poles 

 of the pile. I shall not relate, from fear of prolixity, the nu- 

 merous experiments which have conducted me to this law ; 

 besides, many physicists had already made analogous obser- 

 vations. The theoretical reason for this result may be easily 

 imagined. It is true, that by increasing the surface of the 

 pairs, the quantity of electricity disengaged in a given time is 

 increased, but the interior conductibility of the pile is also 

 increased, as may be readily understood. Now, for effects of 

 tension, these two circumstances nearly counterbalance each 

 other; I am, however, disposed to believe, from experiment, 

 that when the pile is charged with a liquid which is a very 

 good conductor, and which exerts a lively chemical action 

 upon one of the metals of the pairs, an increase of the surface 

 of the pairs diminishes the tension. As to the dynamic effects, 

 it may be clearly seen that when they are produced in much 

 better conductors than the pile, as much is gained by increa- 

 sing the surface of the pile, and in consequence the quantity of 

 electricity which circulates in a given time through these con- 

 ductors. But if the bodies placed between the poles be im- 

 perfect conductors, and only in a small degree better con- 

 ductors than the pile, by increasing the surface of the pairs, 

 the quantity of electricity which circulates through those bodies 

 is increased ; but the conductibility of the pile is also aug- 

 mented, and as that of the bodies interposed between the poles 

 does not alter, a larger proportion of the total amount of the 

 electricities necessarily reunites through the pile itself. This is 

 the reason that in the latter case the dynamic effects do not in- 

 crease with the surface of the pairs in so large ajproportion as 

 in the former case; this is also the reason that in certain dy- 

 namic effects, such particularly as physiological effects, the 

 augmentation is insensible. 



We will now inquire what will be the result, if, without al- 

 tering their surface, the number of pairs be increased, taking 

 care that the additional pairs are exactly similar to those of 

 which the pile is already composed. The following are the 

 results : 



I. That the tension of the pile increases constantly with the 

 number of the pairs, but that for dynamic (magnetic, calorific, 



