﻿Determination of the Ratio of the Electrical Units. 10< 

 resistances. Thus 



E' A-C 



so that 



And 



K. + K, B* J 



A'-C' A-C 

 E^ + JEl, i^ ' 



Capacity 1 . , 



-imply 



But although the condenser method may be the best, it is 

 not so perfect but that a desire remains to see results so 

 obtained confirmed otherwise. The construction of an ab- 

 solute electrometer is beset with difficulties, some of which 

 have been remarked upon by M. Abraham. In point of 

 theory the best arrangement is that described by Maxwell 

 (' Electricity/ § 127, 1873) in which (fig. 5) an inner cylinder 



E%. 5. 



C moves coaxially in the interior of fixed coaxial cylinders A, B. 

 It will suffice to suppose that C and A are at potential zero 

 while B is at electrostatic potential B. 



" The capacities of the parts of the cylinders near the [gap] 

 and near the ends of the inner cylinder will not be affected 

 by the [motion] provided a considerable length of the inner 

 cylinder enters each of the hollow cylinders. Near the 

 ends of the hollow cylinders, and near the ends of the inner 

 cylinder *, there will be distributions of electricity which we 

 are not yet able to calculate, but the distribution near the 

 [gap] will not be altered by the motion of the inner cylinder 

 provided neither of its ends comes near the [gap], and the 

 distributions at the ends of the inner cylinder will move with 

 it, so that the only effect of the motion will be to increase or 

 diminish the length of those parts of the inner cylinder 

 where the distribution is similar to that on an infinite 

 cylinder/' 



* A solution of this problem for the case of two dime7ision$ has been 

 given by Prof. J. J. Thomson (Recent Researches, § 237, 1893). 



