452 Messrs. Guthrie and Boys on 



This is possibly due to the vertical repulsion between the 

 moving magnet and the disk not being quite symmetrical. 

 In Experiment 1 all the data are given ; in Table I. the means 

 only are given. 



Experiment 1. 

 O = 0. 



Maximum deflexion. Minimum deflexion. 



368 363 



365 362 



366 359 



367 357 

 367 359 



Index- wheel went five times round in 49 seconds. 



364 359 



363 360 



364 361 

 Index-wheel went five times round in 49£ seconds. 



366 357 



365 355 

 0=+2°. 



The index-wheel going round once corresponds to ninety- 

 seven revolutions of the magnet. 



Allowing 2° for the effective set, we have a deflexion of 

 360 o, 25 caused by a velocity of 9*825 revolutions a second. 

 In Table I. in the first five lines the rate-observations were 

 simultaneous with the angle- observations ; in the latter six 

 they were taken as in the example given : each result is the 

 mean of about eight observations. 



Table I. 



Angular-velocity, rotations 

 per second. 



Angular torsion, 



0-258 



o 



9-7 



0-527 



19-3 



1-672 



60-5 



1-702 



61-3 



2-517 



91-2 



2-900 



106-9 



5-374 



193-9 



7-886 



285-9 



8-186 



303-9 



9-877 



360-3 



23-307 



840-0 



