Intelligence and Miscellaneous Articles. 77 



0*0219 grm., in which the units of the last figure came out quite 

 correctly with careful weighing. Of course when the magnets are 

 inverted, they must only be touched with tongs or with clean 

 gloves. By means of the balance specially constructed, I hope to 

 get another place of decimals. 



If we have three similar magnets, and the three magnitudes m 1 m 2 , 

 m l m 3 , ra 2 ra 3 , are determined, we get 



,-v/ 



(m T m 2 ) (m l ra 3 ) 



The ratio m l : m 2 was also determined by means of the bifilar 

 magnetometer of F. Kohlrausch. The value found by weighing 

 agreed well with the mean of the magnetometrical values, but the 

 latter varied far more than the former. 



With the dimensions of the balance and of the magnets, the 

 higher members of the expression cannot be altogether neglected. 

 Let the x axis be placed in the axis of the horizontal magnet, and 

 the y axis vertical, let H and V be the moments of the magnets in 

 question, and put 



A=2(/x^ 3 ) and v=2 (fxy z ), 



the more complete value of the members which result, after a 

 combination of the four above-mentioned weighings, is 



n 12.H.V . 40H.V-30 Y.K 



(x= - + s 



The values 



V=* 2and H = ' 2 



may be determined by magnetometrical measurements or even with 

 the balance, if we repeat the measurement with a higher or lower 

 suspension of one of the magnets. If we put 



H=2i)jr and V=2bj) 



then 



h=2\)f and v = 2*v 2 ; 



that is, these first members of the action at a distance are the same 

 as would be produced by two single magnetic points with the 

 quantities +\) and —I) at the distance 2 r from each other, or +b 

 and — b at the distance 2 p. These are what I have spoken of above 

 as the mean distances of the poles. Kohlrausch has observed that 

 with tubular magnets they are usually 4 of their length. In the 

 above magnets they are 0*84 and 0*86. Using this designation, 



G= 



12 HV f , , 20y 2 -15x 2 ) 



J -. . 20y 2 -l5cc J ) 



