1006 
PROFESSOR J. A. EWIXG AXD MISS H. G. KLAASSEX 
Cycle (4). 
1 
Cycle (5). 
Cycle (6). 
H. 
R. 
H. 
B. 
H. 
B. 
6-14 
6230 
5-03 
4220 
3'55 
1290 
3-18 
5830 
2-85 
3940 
2-31 
1130 
1-85 
5600 
1-72 
3690 
0-95 
850 
0 
5150 
0 
3250 
0 
650 
-1-28 
4620 
-1-28 
2760 
-1-03 
240 
-2-57 
3810 
-2-57 
1880 
-2-06 
- 200 
-.3-21 
2800 
-3-21 
750 
-2-79 
- 690 i 
-3-85 
100 
-3-68 
- 950 
-3 55 
-1293 I 
-4-21 
-1520 
-4-47 
-3290 
1 
1 
-5-27 
-5070 
-503 
-4220 
-5-48 
-5.390 
-6-14 
-62.30 
lliNG VI.—Fine Iron Wire. Values of |H dl and Coercive Force. 
Number of cycle. 
Limits of H. 
Limits of B. 
Limits of I. 
jHdl. 
Coercive force. 
1 
12-34 
113.30 
901 
16490 
4-83 
2 
9-14 
9430 
750 
12250 
4-52 
3 
7-30 
7730 
614 
9050 
4-20 
4 
6-14 
6230 
495 
6580 
3-86 
5 
5-03 
4220 
335 
3670 
3-43 
6 
3-55 
1290 
105 
490 
1-65 
The next specimen (Ring VII.) was also of cotton-covered iron wire, of larger 
diameter than the last, namely 0'975 millim. It turned out to be only moderately 
soft in the magnetic sense. In addition to the measurements of magnetic cycles, the 
results of which are given below and in figs. 17 and 17a (Plate 39), several other 
experiments were made with this ring with the view of determining directly the 
heating effect of magnetic reversals. These will be described in a later part of this 
paper. The ring had a mean diameter of 9'6 centims., and the net area of section of 
the iron wire forming its core was I'OO sq. centim, 
