332 Mr. F. C.Webb on "Inductive Circuits," or the 



the prime conductor. The reason of this is easily seen when we 

 consider the problem by means of the theory of inductive circuits. 

 The resistance of the circuit is now increased by the resistance of 

 the dielectric separating the rubber from surrounding objects; and 

 as the rubber has little surface compared to that of the prime 

 conductor, this resistance is much greater than that existing be- 

 tween the surface of the prime conductor and the surrounding 

 objects, so that the resistance of the whole circuit is thus in- 

 creased considerably more than double, — the exact amount of 

 the increase depending, however, on the proportion of the rubber 

 to the prime conductor and the proximity of surrounding con- 

 ductors to it. 



If the rubber is connected to surrounding objects, the only 

 resistance in the inductive circuit consists of the dielectric 

 separating the surface of the prime conductor from the sur- 

 rounding conductors. The quantity generated is therefore much 

 greater than when the total resistance included that between 

 the rubber and surrounding objects. The total quantity of posi- 

 tive generated is accumulated on the prime conductor, and the 

 equal quantity of negative passes to surrounding objects, and 

 there remains until neutralized by recombination with the posi- 

 tive on the conducior. 



In the same way, if we connect the rubber to the interior of 

 a Leyden jar, and the prime conductor to the interior of another 

 jar of equal size, the exterior of both jars being in connexion, 

 we shall be able to accumulate in each about half the quantity 

 that would be accumulated in a single jar with the rubber con- 

 nected to the exterior coating. The resistance between the 

 prime conductor and surrounding objects and that between the 

 rubber and surrounding objects form here two branch resistances, 

 and these, being unequal, cause a slight inequality in the jars ; 

 that jar connected to the prime conductor will therefore contain 

 a little less than the jar attached to the rubber. 



With a voltaic battery and two or more variable lengths of 

 submarine cable the laws of inductive circuits are best seen. 

 Thus, if a battery has one pole insulated and the other pole con- 

 nected to a long length of cable, say a hundred miles, having its 

 distant end insulated, no charge in the cable will take place. 

 The resistances here consist of the envelope of the cable and of 

 the resistance separating the insulated terminal from surround- 

 ing objects. This resistance is practically infinite ; and hence 

 no generation. If, now, a mile length be placed in contact with 

 the previously insulated pole, certain equal and opposite quan- 

 tities will be generated at each pole and charge the cables 

 equally. If the short length is increased, the quantity that 

 will be generated will be increased according to the formula 



