of the Coefficients of Induction. 455 



and will be represented by the ratio of the area enclosed 

 by the lines ON 1? P1N1, and the curve OPx to the square on 

 the line OC,. 



Fig. 1. 



3. Maxwell's method of determining the coefficient gives L 2 , 

 because the quantity of electricity discharged through the 

 galvanometer is proportional to the number of lines of force 

 inserted by the establishment of the current C (or to the 

 number removed by stopping the current), while the steady 

 deflection due to a small derangement is proportional to C 

 directly. The method therefore gives the ratio of N/0 or L 2 . 

 Professor Ayrton has generalized this method by altering the 

 current from one value to another, instead of establishing it 

 from zero to its full value. The quantity discharged through 

 the galvanometer is proportional in this case to N x — N 2 , where 

 Nj is the number of lines of force corresponding with the first 

 current C 1? and N 2 that corresponding with the other cur- 

 rent C 2 . If the steady deflection caused by a derangement 

 from balance be taken when a current C is flowing through 



the coil, Maxwell's formula will give the ratio of — — — -; 



2H2 



