1108 



Mr. V. A. Bailey on a Development 



If the connexions be changed to the arrangement shown 

 in fig. 2, the condition for no galvanometer deflexion is 

 identical with that for Maxwell's arrangement. 



Fig- 2. 



Vtbrat/ng 

 reed. 



^h 



It is found, moreover, that the condition for no galvano- 

 meter deflexion is completely independent of the point in the 

 network to which the condenser is permanently connected. 



This is easily proved by the use of what may be termed 

 the Principle of Superposition, namely : that in any net- 

 work of conductors and sources of e.m.f., the current (or 

 potential difference) between two junctions is equal to the 

 algebraic sum of the currents (or potential differences) 

 between the same two junctions produced by the e.m.fs. 

 acting separately *. 



We will, however, not do this for the arrangement shown 

 in figs. 1 and 2, but will proceed straightway to examine the 

 more general case of a network of conductors with r junctions 

 (fig. 3). 



Fig. 3. 



Between junctions 1 and 2 there is a galvanometer, 

 between junctions M and N a source of e.m.f. E, and a con- 

 denser of capacity C has one set of plates connected to 

 junction X, while the other set of plates touch junctions 

 A and B alternately n times a second. 



* This Principle can be shown to follow from the fact that all relations, 

 amongst the currents and e.m.fs. in a network are linear. 



