1826.] Copper and other Substances during Rotation. 259 



Values of w 



These differ too widely from each other for us to suppose tliat 

 the force varies as any exact power of the distance ; but the 

 approximation is evidently towards the inverse square. 



With regard to the forces with which different discs are 

 urged at the same distance, they appear to be very accurately 

 proportional to the weights of the discs when their distances 

 from the magnets are small ; but as the distances are increased, 

 the forces appear to increase in a greater ratio than that of the 

 weights of the discs. 



Distance 

 Torsion 



Weight 

 Torsion 



Weight 



As it was only by a rough estimate, that I considered the 

 velocity with which the magnets revolved under the disc A 

 was double in one case of what it was in the other, I would not, 

 from these observations, pretend to determine the ratio of the 

 forces as depending upon the velocities, but I should have little 

 doubt that they are proportional. 



From these experiments it appears, that the time in which the 

 disc begins to return, by the torsion of the wire, is the same at 

 all distances ; and from another experiment, it appeared to be 

 independent of the velocity of rotation. This ought to be the 

 case, the force accelerating the disc being constant ; and the 

 retarding force, the torsion, varying as the distance from a fixed 

 point. E. W. B. 



-6 

 1-372 



1-380 



1-1 



-483 



•633 



1-6 

 -194 



*286 



2-1 

 -100 



-134 



2-6 

 -049 



-067 



DiskA. 

 DiskB. 



s2 



