CAPACITY OF A SYSTEM OF CONDENSERS. 7 1 



so that the capacity of this condenser is 



S /i i\ 



c (-+-), 



an expression which agrees with that already obtained (79) for closed 

 conductors. 



83. CAPACITY OF A SYSTEM OF CONDUCTORS. Let us con- 

 sider a number of different conductors whose electrical capacities 



are respectively C, C', C", and which are so arranged that their 



inductive action on each other is zero. If all these conductors, 

 being at the same potential, are joined by means of conductors 

 whose capacity may be neglected, fine wires for instance, no exchange 

 of electricity will take place, for they were all at the same potential, 

 and this potential will not change. 



They form thus a single conductor, the charge of which is 

 equal to the sum of the original charges. The electrical capacity 

 of the system is equal to the sum of the capacities of the separate 

 conductors. 



Let us now suppose that the potentials of the original conductors 

 are different V, V, V", the corresponding charges are 



= VC, M' = V'C', M" = V"C" 



All these charges being regularly distributed upon the single 

 conductor formed by the system, will produce a potential V l given 

 by the equation 



V 1 C 1 = VC+V'C' 

 whence 



1 



This expression is frequently used in experimental researches. 

 It will be remarked how analogous it is to that which represents the 

 temperature resulting from the mixture of several different bodies at 

 different temperatures. 



84. BATTERIES. This term is applied to the system formed of 

 several Leyden jars, or condensers of any kind, which are connected 

 with each other. 



If the condensers are virtually closed, as is the case with ordinary 

 Leyden jars, the external action of each of them is insignificant, 

 and they can be brought near each other without exerting any 

 appreciable influence. 



