of Wires of different Qualities and Dimensions. 5 



ing table ; and in the last column I have given the deviations 

 which ought to have been observed supposing the power of the 

 wires to vary as the square of the diameters. 



Table I. 



With such a series of results, obtained on a large scale, 

 with a powerful battery, and with every necessary precaution to 

 ensure their accuracy, it is impossible, using the deflections as 

 the measure of the conducting power, to arrive at the conclu- 

 sion, that the power of wires of different diameters and of the 

 same length varies directly as the squares of their diameters, 

 or as any power of the diameter whatever. 



A similar discrepancy has place in the law which has 

 reference to the length, M. Becquerel making the power 

 vary inversely as the length, while my experiments make 

 it vary in the inverse ratio of the square root of the length, 

 or at least very nearly in that ratio. I am aware that as- 

 suming this law, viz. /"* , the errors between the computed 



