258 Electric Currents in Networks of Conductors. 



Now it is interesting to note that we may otherwise write 

 the above expression for nK, 



JL -^ 

 nK~ S' 



where A is the determinant, 



R + B + S, -S, -R + S 



-S, Q + S + G, R(|+l) 



-R, -G, Q + S 



and 8 is its first minor, 



R + B + S, -S 



-S, Q + S + G 



and 





is of the dimensions of a resistance. 



The value for nK writes out by a simple transformation into 

 another form, 



S i 1- (Q + S + G)(R + B+S)J 



nK = 



rq{ 



1 + 



SB 



Q(R+B + S) 



}{ 



1 + 



SG 



R(Q + S+G) 



r 



which is the form in which it is given by Prof. J. J. Thomson 

 in his paper, and quoted by Mr. R. T. Grlazebrook in his 

 memoir on a Method of Measuring the Capacity of a 

 Condenser*. 



The above examples are amply sufficient to exemplify this 

 method of treating problems in networks of conductors, and 

 show how it enables calculations to be made with considerable 

 ease, not only of the distribution of currents and potentials, 

 but of the resistances between any points on a network, the 

 branches of which consist either of simple resistances or of 

 wires having self- and mutual induction with other branches, 

 or of electromagnets, or condensers associated with appropriate 

 commutators. 



* This method of Maxwell's, of obtaining the capacity of a condenser has 

 been practically employed, with most excellent results, by Mr. P. T. 

 Glazekrook, F.P ,.S. ; and the full details of the tests to which he subjected 

 the method are given in his paper in the l Proceedings of the Physical 

 Society/ vol. vi. part iii. p. 204 (June 28, 1884;. [Phil. Mag. for August 

 1884, p. 98.] 



