154 



Physical Society.* He did not, there- 

 fore, think that the arrangement could 

 be taken as one which would give a non- 

 self -induction in the external circuit. 

 The author had stated (p. 61), "the 

 coefficient of self-induction was found to 

 be L = 0.955 in C.G.S. measure, and 

 0.0955 in practical units." C.G.S., of 

 course, meant centimeter-gram-seconds ; 

 what " practical " units were he did not 

 know. If they were the ordinary units 

 of self-induction, corresponding with the 

 true ohm, the volt, the ampere, and so 

 on — then 1 practical unit was equal to 10" 

 C.G.S. units or centimeters. The number 

 0.955 given by the author should have 

 been divided by 10 9 or one thousand 

 million ; or more strictly, in consequence 

 of the ohm not being the true ohm, the 

 practical unit of self-induction was 99,777 

 X 10* centimeters. Hence the coefficient 

 of self-induction referred to by the 

 author was 0.9571 X 10" 9 centimeters in 

 practical units, which would be about 



♦Proceedings of the Physical Society of London, 

 1888, vol. ix. p. 287. 



