19G 



REPORT — 1895. 

 Ohms — continued. 



The resistance coils referred to in tlie last report as defective in 

 insulation have been refilled, and up to the present their insulation has 

 proved satisfactory. 



The puljlication of a paper handed in by Dr. Muirhead, giving; further 

 results of tests made by Mr. E. O. Walker on the coils made by Dr. Mat- 

 thiessen twenty-five years ago, and since exposed to an Indian climate, is 

 deferred until the Cambridge coil, against "vvhich they were tested, can be 

 re- examined by the Secretary. 



The .set of standards ordered from Germany lias only just arrived. 

 In the coui'sc of the next year a careful comparison will be made between 

 their values and those of the standards of the Association. 



During the year the Committee have had under discussion a paper on 

 magnetic units prepared by Dr. Lodge and printed as an appendix to this 

 report, together with a communication received from Dr. Everett. 



Taking into account the fact that the question of magnetic units is still 

 under di.scussion by various bodies, the Committee wish to come to no hasty 

 decisions, but they recommend for tentative adoption the following ter- 

 minology : — 



1. That, as a unit for magnetic field, a hundred million 'c.g.s. lines' 

 be called a u-eher. 



Xotf. — A weber added per second at a steady rate to the field girdled 

 by a wire circuit induces one volt in every turn of that circuit. 



Hence thewebers ' cut 'by a closed wire circuit of n turns are equal to 

 the quantity of electricity in coulombs thereby impelled round that circuit 

 multiplied by Hh its resistance in ohms. 



2. Tliat the c.g.s. unit of magnetic potential or of magneto-motive force 

 be called a gauss. 



Note. — An ampere-turn corresponds to - (or 1-2560) gauss. 



Hencr the number Df gausses round any closed curve linked on an 

 ' Retested (see Report for 1894). 



