504 



WBBER ON THE MEASUREMENT 



If in this formula we substitute the values known from direct 

 measurement in millimetres, 



m = 44*4 

 n' = 50-25 

 n" = 61-35, 



we obtain as tlie I'otatory momentum the following value to be 

 multiplied by in: ii : — 



+ 442-714, 



This value suffers a reduction of about gV^^ when we take into 

 consideration that all the turns of the two coils do not lie in one 

 plane, which in this case exerts greater influence on account of 

 their proximity than in the other cases. The above value thus 

 becomes reduced to 



+ 427-45 .TTTrii. 



The numerical coefficients thus calculated should now be pro- 

 portional to the observed values ; and when multiplied by tttt ii, 

 the intensity of the current i being expressed according to the 

 dimensions upon which the above measurements were based, 

 should be equal. 



In fact, when all the calculated numerical coefficients are mul- 

 tiplied by 53*06, and then arranged according to the analogy of 

 the observed values, we obtain the following table of the calcu- 

 lated values, and their difference from those found by observa- 

 tion: — 



In this comparison of theory and experiment, the single factor 

 53*06 was deduced from obsei-vations ; and this was merely done 

 because this factor could not be determined with sufficient ac- 

 curacy by dirrct measurements. The direct determination of 

 this factor is based upon the ascertainment of the proportion of 

 that measure of the intensity of the current, upon which the 

 scale of the galvanometer used is based, to that absolute measure 

 to w^hich the theoretical expression refers. The measurements 



