668 



sibilities to determine the currents for A and B in ampères, from 



C X V-increase per seo. 



the formnla : i i = :r;zTz , in which C represents 



9 X 10^1 



the capacity of the needle b -\- d. As mean values from the values 



for the 3 most insensitive states we thus obtained : 



24 = 1.3 X 10-13 (quantity B) 



Ia — 3.3 X 10-'3 { „ A) 



Limits of sensitivitij of the apparatus. 



Besides being dependeiit on the state of charge of the system, the 

 sensibility of charge can also be modified by varying the thickness 

 of the suspension wire and the angle between the needles. 



It was now of interest to ascertain how far the infinence of 

 a change of the state of charge in this respect could extend, how 

 far in other words the apparatus might gain, resp. lose sensibility 

 of charge by a constantly increasing or diminishing potential difference 

 between a and b. Experiment showed, that there are limits on either 

 side, at which the apparatus presents a very peculiar character; 

 this will successively be examined for a smallest sensibility, and 

 then for a greatest sensibilitj^ 



a, Limit of smallest seyisibiiiti/. 



Though for the just mentioned state of charge (-[- 8, 0, -|- 2) V 

 the phenomena were similar to those for the other states of charge, yet 

 the limit of sensibility appeared to be close in the neighbourhood, 

 viz. at the state: (-f- 4, Ü, 0) V ; this will most clearly appear from 

 the experiment in which the potential sensibility was examined by 



15 



21 



i6 



Fig. 3,. 



Votti 



iZ 



