VOLTAIC GENERATORS. 33 



distributed among all the circuits, as the water of a reservoir 

 would be among several discharge-pipes, and that the resistance 

 then opposed to the propagation of the electricity is equiva- 

 lent to that of a single conductor of a section as many times 

 greater as there are derived circuits. Now as the electric resist- 

 ance of a conductor is in inverse proportion to its section, it will 

 be at once seen why in this case the battery must be arranged 

 in such a manner as to have its resistance greatly lessened. 



It is not necessary that the several elements of a battery 

 should be directly connected together ; they may be joined 

 by conductors of greater or less length. For instance, one 

 part of the battery may be at one end of the circuit, the 

 other part at the opposite end; and according to the manner 

 in which these two parts are connected by the two conduc- 

 tors of the circuit, we shall have a battery arranged for ten- 

 sion, or with a double surface (quantity). Only in this last 

 case will it happen that all the connecting wires between the 

 two conductors will transmit the current with exactly the same 

 intensity, at whatever point of the circuit the junction may 

 be made. This will be easily understood, if we reflect that 

 the connecting wires of the two parts of the battery then form 

 electrodes charged to the same potential throughout their 

 whole extent, and that the poles of the battery will then be 

 placed at the two points where the wires are attached that 

 are to supply the work. 



If the resistance of the external circuit and that of an 

 element of the battery are known, the most suitable arrange- 

 ment for the elements of the given battery can be imme- 

 diately determined without trial by means of the two following 

 laws, which I have discussed at length in my Expose des appli- 

 cations de F electricity tome L, p. 145. 



i. The number of elements in each group to be arranged 

 for quantity is given by the whole number nearest to the 

 square root of the product of the total number of elements 

 in the battery into the resistance of a single element, divided 

 by the resistance of the external circuit. 



