ANALYSIS OF THE CALVANIC PILE. g53 



motion by the property of the pile. This motion is very because the 

 slow, compared with the motion of an external quantity of ^5}°"^^^ 

 electric jluid* The smallest degree of electrification of an by the pile is 

 insulated body, positive or negative, such as can only affect vef y slow * 

 the gold leaf electroscope, communicated to one side of a 

 pile, is instantly manifested at the other extremity ; but it 

 is by no means the same with respect to the electric fluid set 

 in motion by the property of the pile: when the electro- 

 scopes diverge equally at its extremities, having touched 

 one of them, which makes the gold leaves fall here, and 

 rise more on the opposite side, it requires a time, often 

 very long, before the same divergence is restored. This is 

 the reason why f was obliged to fix 20 seconds for the du- 

 ration of the contacts of my piles of 20 groups with the 

 condenser, in order to be certain, that the maximvm of effect 

 was produced; it requires more or less time, according ei- 

 ther to their nature, or to the extremity applied to the cOn- 

 denser; but I found, that the slowest was produced in 20 

 seconds, which made me fix that time. 



This will explain the case above mentioned, that there is 

 no sensible effect on the condenser by any number of al- 

 ternate contacts of an insulated body with the paper 

 laid on the zinc side of one group ; and even, when the 

 groups are multiplied to increase the effect, it requires, to 

 make it sensible, a prolongation of the contact on the little 

 pile, in order to give time for the effect to be propagated; as 

 will be seen by the following experiment. 



Exp. 34. Made with a portion of my pile of 10 groups Exp, 34. 

 of 1*6 inch diameter, successively tried by each of their 

 extremities, the opposite one being placed on the movable 

 pillar of my condenser, and the alternate contacts being 

 made with a small insulated disk of the same diameter. 



1. N<» number of alternate contacts, between either of 

 the extremities of the little pile and the condenser, produced 

 any sensible effect on the latter when rapidly made, or in 

 the manner they are executed between the two naked disks, 

 zinc and copper. 



2. On repeating the experiment, with the zinc side on the 

 pillar, and lengthening the time of the contact on the copper 

 side up to 4 seconds, I found, that by 20 such contacts the 



electroscope 



