466 



EEPOET 1884. 



Clifton, by Ayrton and Perry, by von Zahn, and by most otber experi- 

 menters on the subject. 1 



Fig. 1.— Kohlrausch's Early Form of Condenser. 



Both the plates are insulated bv silk t oreads. The fixed wire d, with which the raised plate 

 comes into contact, leads to a Dellman electrometer. The connections are arranged for 

 determining the ' electroscopic tension ' on the poles of an open battery, to see if it is tn< 

 same as the E.M.F. See Pogg. Ann. 1848, vol. 75, pp. 88 and 2'20. 



This apparatus he also used to measure the Volta effect between two metals, his classical 

 memoir on the subject being in Pogg. Ann. 1851, vol. 82, p. 1. Later he improved 

 the condenser, bringing it into the form shown in the following figure. 



Fig. 2. — Kohlrausch's Later Form of Condenser. See Pogg. Ann. 1853, vol. 88, p. 464. 



1 Kohlrausch's method consisted in bringing the plates of the two metals close 

 together, connecting them by a wire for an instant, separating them, and putting one 



