!38 M. W. Weber on the Measurement of Electric 



A. 



B. 



t. 



0028645 

 0-027955 

 0028565 



o o o 



5 a o 

 o a a 



6 6 6 



91128 

 9-1148 

 9-1107 



0-028388 



0000400 



9-1128 



From this we obtain, according to Brigg's system, for that 

 part of the logarithmic decrement arising from the deadening, 



0-0.28388 - 0000400 = 0-027988, 



or according to the natural system, 



X= 0-064445. 



The bar magnetism of the oscillating needle M, determined from 



magnetometric measurements, was found, according to absolute 



standard as compared with the horizontal part of the earth's 



magnetism T, 



M 

 ^=20733000. 



That part of the directive force of the needle arising from the 

 elasticity of the thread was found to be 68 times less than that 

 arising from the magnetism, or 



jj_ _68 



1 + "69" 



For the calculation of the resistance from these observations, 

 executed on the principle of deadening, we have the following 

 rules. 



According to the law of magnetic induction, the electromotive 

 force of a small magnet oscillating in the centre of a circular 

 conductor, whose magnetic axis makes the angle </> with the 

 plane of the circle, is directly proportional to its magnetism M, 



to the cosine of the angle (f>, and to the velocity of rotation ~, 



and inversely proportional to the diameter of the circle r ; and 

 if M is expressed according to an absolute measure, is deter- 

 mined by 



2ttM , d<f> 



— • cos$ — 

 r 



T at 



On the contrary, according to electro-magnetic laws the mo- 

 mentum of rotation which the induced current in the circular 

 conductor exerts upon the small magnet oscillating in the centre 



