134 Dr. J. Moser on the Division of Induction in the 



have in the one case to be regarded as lines of force, and in 

 the other as lines of flow. The greater the plates are, the more 

 nearly flat are the surfaces of electric level, and the straighter 

 are the lines of force. 



Induction and conduction act, therefore, in the same lines. 

 If, in order to fix our ideas, we take spermaceti as an inter- 

 vening plate, as Faraday did, we find, with him, " spermaceti 

 to be a dielectric, through which induction can take place " 

 (Exp. Kes. § 1322). But "spermaceti is also a conductor, 

 though in so low a degree that we can trace the process 



of conduction, as it were, step by step through the mass 



Here induction appears to be a necessary preliminary to con- 

 duction" (§ 1323). And although Faraday could not, as we 

 have done, formularize the division of the induction in the 

 same way as the branching of the current is formularized, still 

 he had this agreement in his mind. That he could not formu- 

 late this idea was the reason why he was misunderstood ; and 

 this is the reason which has induced me to examine the point 

 more carefully. 



In one case of electrostatic induction through the air 

 Faraday replaced a part of the air by sulphur, and found 

 that the induction was now greater than when the air was 

 there which the sulphur had replaced. 



He now compares this case with that of the branching of 

 a current in bad conductors, one of which he replaced by 

 a good conducting wire. Then a stronger current would 

 flow through the wire than flowed through the bad conductor 

 which it had replaced. And as much less electricity would 

 flow through the remaining bad conductors as more through 

 the wire. 



This is the meaning of Faraday's words, " Amongst insu- 

 lating dielectrics some lead away the lines of force from 

 others as the wire will do from worse conductors " (§ 1331). 



I shall, in the following, consider some of the applications 

 of this conception of the inductometer as a dividing of elec- 

 trostatic induction. 



Method for Determining Inductive Capacity. 



The methods for determining electrical resistance which are 

 based upon division of the current may be transferred to the 

 measurement of inductive capacity. In Wheatstone's bridge, 

 for example, first given by Christie, we determine an unknown 

 resistance as a fourth proportion to three known resistances. 

 For this purpose, the current between a point of higher and a 

 point of lower potential is divided. Two points, one on each 

 of the branches, are found having equal potential. They 



