35 



coatings, which made all the conditions necessary to the 

 perfection of the common battery ; and I found it capable of 

 being charged by the electrifying machine in this form, but 

 it could not be charged to any extent in the other. It ap- 

 peared, that but few sparks would pass from the conductor 

 to the first jar. If the last one was removed, and its chain 

 fastened to the next, the first jar would take a iew more 

 sparks, and so on ; for it was found that whenever the last 

 jar in the series at any time was removed, the same results 

 followed ; and this was the case when the last but one was 

 removed, clearly proving, that the capacity or aptitude of 

 the first jar to take a charge was influenced and diminished- 

 by the second, more so by the third, fourth, &c. Its apti- 

 tude was greatest when it was by itself, and not connected, 

 as described, with the others. 



" This result disappointed my expectations, so far as my 

 intended improvement on the electric battery was concerned; 

 and it also appeared to point out the existence of a principle 

 influencing the charge of the electric jar, which was not 

 recognized in the popular treatises on electricity. I procured 

 a number of glass plates with fixed and moveable coatings. 

 These plates were insulated and arranged with and without 

 coatings in every way that Brand's rule required, but the 

 general result was the same as that given above. 



" From numerous experiments made with these plates, I 

 came to the following general conclusions : 



" I. That the actual quantity of the positive and negative 

 electricities which we can accumulate in the opposite sur- 

 faces of an electric or non-conductor, as a plate of glass or 

 dry ice, depends upon the distance of these surfaces. 



" 2. Every case of charge of owe jar or plate may be assimi- 

 lated to that of any number of jars or plates in a series, such 

 as Brand's, by supposing the one jar or plate to be divided 

 into the greater number, its thickness being the sum of the 

 thicknesses of all the segments or plates t The inside of the 



