498 



WEBER ON THE MEASUREMENT 



The first experiment was made by passing three currents of 

 ditferent intensity, i. e. from 3, 2 and 1 of Grove's elements, 

 through the two conductors of the dynamometer, and observing 

 the simultaneous deflections of the dynamometer and galvano- 

 meter. After making the necessary reductions, the following 

 means were obtained as the deflections : — 



These observations are reduced so that the former furnish a 

 measure of the electro-dynamic force with which the two con- 

 ductors of the dynamometer act upon eacli other, when cuiTents 

 of equal intensity are transmitted through them, whilst the 

 latter furnish a measure of this intensity itself. 



If we denote the dynamometric observations by 8, and the 

 galvanometric observations by y, we obtain 



y = 5-15534 . Vh; 



for if we calculate the values of y from the values found b}' ob- 

 servation for 8 according to this formula, we obtain in the order 

 of the series, 



108-144 



72-589 



36-786, 



which exhibit less difi^erences from the values of y found by ob- 

 servation than could be anticipated, thus : 



— 0-282 

 + 0-191 

 -1- 0-454. 



The electro-dynamic force of the reciprocal action of two con- 

 ducting wires, through which currents of equal intensity are trans- 

 mitted, is therefore in proportion to the square of this intensity, 

 which is exactly what is required by the fundamental principle 

 of electro-dynamics. 



A more extended series of experiments was then made for the 

 purpose of ascertaining the dependence of the electro-dynamic 

 force, with which the two conducting wires of the dynamometer 



