A. Kendrick — Damping of Bell-magnets, etc. 457 



latter being, apparently, the greatest possible permanent 

 moment for Q, its value, about 52 cgs units ; the earth's field 

 and a considerably weakened field ; a variety of shapes and 

 sizes of the copper boxes, and one box of brass. Box 1 was 

 bored to successive depths 1st, 2d, 3d, 4th as shown in fig. 1, 

 the 4th meaning that it was bored quite through. Box 4 was 

 given successive interior diameters, a, o, o. With 1 (1st), 3 

 and 4 (a), all of the same interior diameter, the A's were found 

 for the five different inertia moments and the three magnetic 

 moments. Using the A's for ordinates and the relative inertia 

 moments for abscissas and plotting a curve for each of the 

 three boxes for each magnetic moment there results nine 

 curves, or three sets (corresponding to the magnetic moments) 

 of three curves each (each curve of a set corresponding to a 

 box). Fig. 7 presents two of these curves. I is plotted from 





Fig. 7. 













0.3 









■ i2 + I 



y 

















yJl 

















*s 







0,20 









/ 













0. 10 





.0 9 















I 





04- 

















1 



< 













•* 



o> 





t* 







3| 







«ii 



C4, 





CO| 



Mom«n* of Inertia > 



A's given by Q in box 1 (1st) with relative magnetic moment 

 1*0, and II, from Q in boxes 3 and 4 (a), (these two giving 

 nearly the same damping). The two other sets of curves from 

 relative magnet moments 0*68 and 0*44 would be located 

 respectively above curves I and II and are very similar to 

 them. The relative moments of inertia are plotted as abscissae 

 and the A's as ordinates. Plotting the relative magnetic mo- 

 ments of Q as abscissae and the A's as ordinates, and using 

 relative inertia moment 3*7 and box 1 (1st), we get I of fig. 8 ; 



