1036 
PROFESSOR J. A. EWIRG AND MISS H. G. KLAASSEN 
directing force, the current in the coils was slowly increased by means of a liquid 
rheostat, and galvanometer readings of it were taken, along with magnetometer 
readings of the aggregate moment. The numbers (with arbitrary scales) are given 
below, and are drawn as a curve in fig. 35. The highest value of the current was 
Fig. 35. 
Cnrve sliowing the behaviour of a group of 130 pivotted magnets subjected to increasing 
airecuve lorce. 
strong enough to bring the group of magnets to a configuration approaching satura¬ 
tion.” It will be seen that the three stages of the magnetizing process are well 
reproduced in the behaviour of the model, and, notwithstanding the limited number 
of “molecules” which took part in the operation, the readings lie faiidy well on a 
smooth curve, which has all the general character of the curve of magnetization in 
actual iron. 
1 
Current. 
Moment. 
Current. 
Moment. 
0 
0 
4 
0 
58 
41 
10 
1 
63 
48 i 
17 
3 
83 
119 ; 
26 
5 
145 
145 ! 
33 
11 
184 
160 i 
41 
11 
447 
174 ; 
50 
28 
1 
i 
In the same way fig. 36 shows the results obtained in carrying a group of pivotted 
magnets through a complete cycle, by double reversal of the directing field, after the 
cycle had already been gone through once or twice. Fig. 37 shows an immediately 
succeeding experiment on the same group, designed to illustrate the formation of small 
