tn the Charging of a Condenser. 3\)h 



<p = arc tan ., A/ -j-—, — j^j we nave M our final expression 



for the difference of potential of the two surfaces of the con- 

 denser, 



Pt-P.^E / 2L Rgu sin ( 2 ^+»)- ■ ' ( 8 ) 



Equation (8) is only exact on the assumption that the capacity 

 of a condenser is independent of the time. The capacity being 

 a function of the time*, the equation is simply valuable as 

 indicating the general character of the oscillations, and how 

 their amplitude should be influenced by changes in the values 

 of any of the various quantities that enter into the expression 

 for the amplitude. 



From equation (8) we have the amplitude of the oscilla- 



R t 

 Ee~^ 

 tions equal to , From this it would follow that 



an increase in the amplitude of the oscillations in the differ- 

 ence of potential of the two surfaces of the condenser corre- 

 sponds to a decrease in the time or of the resistance, and to 

 an increase in either the electromotive force, the coefficient 

 of self-induction, or the capacity. 



The following determinations, which are to be considered 

 simply as qualitative in their nature, were made to see in how 

 far the observed variations in the charge followed laws similar 

 to those given by equation (8) for variations in the difference 

 of potential of the two surfaces of the condenser. Two con- 

 densers were used in these experiments. One was a standard 

 microfarad mica condenser, manufactured by Carpentier of 

 Paris, and subdivided into 0*5, 0*2, 0*2, and Ol microfarad. 

 The other was a microfarad paraffin condenser, manufactured 

 by the Societe d'exploitation des cables electriques of Cor- 

 taillod, Switzerland. 



* \V ullnei', Sitzungsb. koniyl. bayer. Akad. 1877, p. 1. 



