ON THE ELECTRIC COLUMN. §7 



under two distinct points of view, on one of which I have 

 already given an experiment in my former paper; but I 

 have repeated it in a different manner, which will confirm 

 my system on these phenomena. 



Exp. 14. The column of 600 groups, represented in the Exp.t4, 

 figure, has been composed of three columns of 200 groups 

 each, which I had used separately from the beginning of 

 these experiments; but before they were united together for 

 the purpose of the aerial electroscope^ I tried their effects in 

 the three following combinations. 



1. I applied successively to the same electroscope the same 

 extremity (either positive or negative,) of each column, the 

 opposite extremity being placed in communication with the 

 ground ; and I observed the quantity of divergence produced 

 by each column, which was nearly the same. 



2. I applied the three columns at the same time to the 

 electroscope, each of them remaining in communication with 

 the groMiu' ; and the divergence was not greater than it had 

 been with the most active of the single columns. 



3. But having connected the three columns as one, by 

 placing conductors between their opposite extremities, and 

 connecting one extremity of the whole with the electroscope, 

 the other being in communication with the ground ; the ef- 

 fect was so much increased, that the gold leaves struck the 

 sides of the electroscope. 



This proves, under a different form, the same proposition Number of 

 which I had stated in my former paper, namely, that the P'^t^s analo- 

 siraple divergence in electroscopes depends only on the den- f^n"gth*of a 

 sity of the electric fluid, and the density on the number of pump for ra^s- 

 groups ; at the same time that it confirms the cause * * 



which I had assigned to these effects; and as they are ana- 

 logous to many kinds of phenomena, I shall use another 

 example to explain it, that of pumps. As the height to 

 which water can be raised hy pumps does not depend on ei- 

 ther their number or size, but on their length ; so in the 

 above experiment, with three concurrent columns of 200 

 groups, the density of the elecfyicjluid was not increased on 

 one extremity, nor consequently the divergence at either ex- 

 tremity, more than with one column ; nor could more have 

 been done with one column of the same number of groups 



VoL.XXVII^OcT, 1810, H of 



