IRON AND STEEL IN A ROTATING MAGNETIC FIELD. 
743 
number of combinations. This would account for the increase in the hysteresis, and 
also for its irregular value before it again reached its normal value. 
[It will be noted that while the average values of hysteresis obtained in the 
Tables X. to XIV. agree for the most part very closely with those in the previous 
tables ; the values at the maximum are distinctly lower, both in iron and steel, 
indicating a greater “ accommodation ” under the long continued running in the critical 
condition.—2nd September, 1896.] 
In the hard steel these effects are very much diminished, the deflexions being more 
uniform and consistent. The same difference is shown in the constancy of the 
hysteresis at the maximum point. In the steel, all the curves agree very closely in 
the maximum value attained, Diagram 4, and the speed curve at that point, 
Diagram 11, although somewhat irregular, is much less so than the curve from soft 
iron. This follows from the supposition that in steel the aggregations of molecules 
are smaller and less dependent on each other, and hence the average behaviour is 
more regular. 
Table X.—Hard Steel Armature of 147 Plates, of thickness ‘0141 centim. Varia¬ 
tion of Hysteresis with Speed ; Diagram 11 ; Deflexions on Scale : 1 division 
= 502 ergs per cub. centim. per rev. 
Speed in 
revs, per 
B = 2600. 
4000. 
4600. 
8100. 
12,100. 
14,700. 
15,700. 
17,700. 
sec. 
•14 
9-3 
18-8 
51-6 
17-5 
9-3 
18-8 
21*5 
47-5 
# 
# . 
51-0 
21 
9-3 
18-8 
21-5 
47-0 
70-2 
75-6 
71-0 
49 9 
24-5 
9-3 
18-8 
22-0 
46-7 
70-1 
75-5 
71-5 
48-9 
28 
93 
18-8 
22-0 
46-3 
70T 
75-4 
71-4 
48-8 
31-5 
9-3 
18-8 
21-7 
45-7 
70-5 
75-4 
71-4 
49-7 
35 
9-3 
19-0 
22-0 
45-5 
71 5 
751 
70-3 
49-1 
38-5 
9-3 
18-8 
# . 
46-0 
710 
75-4 
70-2 
495 
42 
9-3 
19-0 
22-0 
47-0 
69-8 
73-8 
69-1 
50-4 
45'5 
9-3 
18-7 
21-6 
46-0 
71-2 
75-2 
70-2 
52-3 
49 
9-3 
18-8 
21-0 
44-0 
713 
74-1 
70-2 
52-1 
52-5 
9-3 
19-0 
22-0 
45-0 
, . 
76-2 
70-0 
491 
56 
9-3 
19-1 
22-3 
46-0 
713 
77-3 
7L4 
51-0 
59-5 
9-5 
191 
21-3 
45‘5 
73-2 
78-4 
74-8 
56-9 
63 
8-9 
185 
2L0 
45-5 
72-2 
75-9 
71 -7 
53-8 
66-5 
9-0 
19-0 
21-0 
73-6 
.. 
70-6 
50-2 
Value of "I 
i eddies in 1 
scale i 
] division J 
- 0005w 
•0013m 
•0016 
•0050 
•012m 
•017m 
•020m 
- 025m 
Average 1 
value of > 
hysteresis J 
4170 
9450 
11,600* 
24,700* 
35,300 
37,600 
35,100 
25,100 
* Value of spring 1 division = 537 ergs per cub. centim. per division. 
