Dr. Tyudall on the Laws of Magnetism. 



277 



the wire of the rheostat the ball gave way ; and then, instead of 

 turning the handle backwards vintil all the wire was excluded, 

 to turn it back so far as to permit the passage of a current which 

 was barely sufficient to overcome the weight upon the scale-pan. 

 The descent from this point to that where the ball separated was 

 so very short, that the fraction of magnetism remaining, if such 

 remained at all, might be neglected. Applying this mode of 

 experiment, the case of contact was first investigated with three 

 smooth spheres of the following dimensions : — 



No. 1, diameter 0'95 of an inch^ weight 65"25 grms. 



No. 2, ... 0-48 ...,, ,,,. ... 9- 



No. 3, ... 0-287 ..r- f /J; ... 1-7. ... 



The iirrangement of the following table is similar to that of 

 Table II. In each case the angle given is the mean of fom' ob- 

 servations, t.i; Sf, 8y 



Table V. 



,,1^9^, I Jt^ all tbese Cfi'8,esvfP,9Jl?8pn':e! a gradual decrease of the 

 quotient ^y- from top to bottom. The same discrepancy ex- 

 hibits itself when we operate with the leaves. This is shown by 

 the following table, the arrangement of which is similar to that 

 01 rablc 1\. iii;(iiioi'i<' /iiii-iii firini inijji'jj^i: 



