106 ' Prof. T. R. Lvle on the Variations of 



Experiment with Ring I. 



Resistance in y circuit = >\ = 5030 &>. 



„ in /3 circuit — i\— 15030 <o. 



Period by chronograph =T = '0307 sec. 

 Kelvin -balance reading of current C at start ='1873 amp. 

 „ „ „ at tinish=-1868 amp. 



Reducing factor of galvanometer=X = 1*287 X 10- 8 amp. 

 M of air-circuit transformer =0*00061 henry. 

 Secondary turns on rmg=w 2 =5. 



Divided } 

 Circle, j 





 103 



6 



338 



12 



583 



18 24 



30 



36 



42 



48 



54 



60 



1069 

 795 



66 



872 



785 



72 



638 

 760 



78 



84 



4y 



795, 1003 

 -296 -82 



1160 

 183 



1270 

 449 



1323 

 661 



1314 

 774 



1239 

 804 



395 147 



4/3 



-636 



-561 



-450 



729 690 



Each of these numbers is the sum of four separate readings 

 of 7 or of /3, two of these being at corresponding points on 

 the positive and negative halves of each wave, and the other 

 two being a similar pair got after switching the galvanometer. 



Analysing the above, we obtain 



4 7 = 1293 sin cot-U sin 3 (cot — 7) + 5 sin 5 (art— 23*4) 



4/3= 868 sin («*-51'76) + 120 sin 3 (arf-63'1) + 23 sin 5 (arf-69-2) 



6. The factors (c and / say) to be applied to the different 

 values of 7 and of /3 in order to obtain the corresponding 

 values of current (C) and of flux (F) are (see Phil. Mag. 

 loc. cit.) 



c — 



which become 



Xr x T 

 4M 



/= 



\nT 



c = -00008145, 



4n 2 ' 



/=29-7 



(1) 



for the experiment being discussed when the figures given 

 in § 5 are substituted. 



These factors can also be obtained from the Kelvin- balance 

 reading C of the magnetizing current ; for if 7 be the 

 R.M.S. of the 7 readings 



C = cy 

 and 



7 2 = ifri 2 4-Y3 2 + 75 2 + ...} 



where y l9 73, 7.3, <fec. are the amplitudes of the first, third, 

 fifth, &c. harmonics of 7, and these have already been 

 obtained by analysis (§ 5). 



