40 



Prof. H. F. Weber on Electromagnetic and 



where B denotes the moment of torsion of the cocoon-thread, 

 M the magnetic moment, and 21 the distance of the pole- 

 points of the small magnet. 



If we call T the duration of an oscillation of the small mag- 

 net, X the logarithmic decrement of the amplitudes of the 

 oscillating magnet in the closed multiplier, G the electro- 

 magnetic force with which the multiplier, passed through by 

 the current 1, acts upon the magnetic unit of mass ( + 1) pre- 

 sent in one pole-point of the magnet, and, lastly, a the arc 

 which the magnet describes from its position of rest in conse- 

 quence of the action of the induced integral current^', then 

 the absolute electromagnetic measure of the integral current 

 generated 



• H a t/iV B \ 7 



G 



According to this, we have for the absolute value of w :- 



.g(i- 1s - 2 ) 



w = P. 



4 R 2 / tan u 



2T.<£ 



G= 



2tt. 



n. 1 



For the multiplier used, G had the value 

 f i jl ] l$\-$ r 2 / _r 2 \_b (I _ 5 TP\ 

 i+ r 2 {3 2p 2 \ p 2 ) p 2 \2 2 P V 

 3 Z 2 r 4D 2 -r 2 h 2 f5 

 "4p 2 L 



V 



{i- 



P 



56 D 2 



P'LS 

 4D 2 -r 2 



P' 

 14^ 

 3 d 2 + 



P 

 4D 2 - 



r 2 /21 21 D 2 ^-, 

 \6 + 2 p 2 )\ 



r> 



and there were 



n=370 



r = 163*2 millims. 

 p= 164-5 

 D= 20-7 



a-s?)}] + - 



2A = 18-0 millims. 

 26 = 33-5 „ 

 2Z=33-0 „ 



To find the value of the Siemens unit of resistance in absolute 

 measure, two ways of proceeding were adopted : — 



(1) The resistance iv was measured in Siemens mercury 

 units by the bridge method. It was found that w was equal 

 to m Siemens units. Thus the absolute value of 



1 S.M.U= 



P.R.G 



' V 1 4 RV 



m . T . ea 



t&nu 

 a 



