SS^ LENZ OX THE COKDUCTIBILITY OF WIRES FOR ELECTRICITY. 



Supposing therefore that the conductibility is in a direct, and the con- 

 ducting resistance in an inverse ratio to the thickness of the wires, and 

 that a, a', a" represent the angles of deviation, we have the following 

 equations : 



A 



— =»-sin(la) 

 =j9-sin(ia') 



1 



"*" 7,737 



^ "*" 5,025 



— =p-s\n{\a") 



&c. 



Dividing the first equation by all the following seven, and putting 



for brevity sake 



a' a" 



sin (ia') = a', &c. and ^j^;;^ = V, ^:^ = I", &c., 



we obtain the following equations : 



ax — y =0 



a' X — y + h' =0 



o" ar — y + a" = 



a"'x-j/ + a"' = o, 



&-C. 



From these equations were determined, according to the method of 

 the least squares, the values 



X = 0-40679 y = 0-29146. 



and finally the values a, a', a", by substituting the foregoing values in 

 the equations, and developing a, a, a". ...or sin ^ a, sin ^ a', sin 4 a", 

 &e. These values are placed in the above table under the head " Cal- 

 culated Deviations." The differences between these and the observed 

 angles of deviation, contained in the last column, are greater than 

 those of the preceding observations, and even greater than can be as- 

 cribed to mere errors of observation ; but the reasons of this have been 

 .already explained. Their agreement, however, is in every case great 

 enough to remove every doubt with respect to the correctness of th( 

 hypothesis (which is the basis of the calculation), that the conductibiliti 

 of wires is in a direct ratio to their sections. 



