78 
MESSRS. G. F. C. SEARLE AND T. G. BEDFORD 
Load, 
Ho = 
37-4. 
Ho = 26-64. 
Ho = 15-72. 
Ho = 
10-0. 
Ho = 
= 5-0. 
grms. 
i 
1 
Bq. i 
W. 
Bo. 
tv. 
Bo. 
tv. 
Bo. 
tv. 
Bo. 
tv. 
0 
14890 
46800 
13000 
36400 
9060 
18100 
4350 
5310 
674 
190 
200 
14860 
46900 
12920 
36500 
8840 
17620 
4410 
5650 : 
690 
196 
400 
14810 
47200 
12800 
36600 
8520 
16950 
3980 
5070 ' 
685 
194 
600 
14520 
47400 
12560 
36000 
8130 
16180 
3420 
4190 
677 
206 
800 
14290 
47100 
12460 
35600 
7700 
15300 
3020 
3760 1 
621 
165 
1000 
14060 
46500 
12040 
35200 
7360 
14560 
2840 
3320 ; 
628 
173 
1200 
13760 
45700 
11700 
34200 
- 7100 
13950 
2600 
2890 ' 
602 
166 
1400 
13540 
44600 
11420 
33500 
6800 
13550 
2480 
2730 
584 
151 
1600 
13200 
44000 
11130 
32800 
1 6600 
12980 
2390 
2540 
547 
130 
1800 
12910 
43200 
10850 
32000 
6330 
12510 
2260 
2.350 
547 
129 ; 
2000 
12760 
42300 
10600 
31300 
i 6210 
12050 
2190 
22.30 
556 
140 
1600 
13210 
43900 
11100 
32700 
6520 
12660 
2330 
2310 
552 
126 
1200 
13780 
45700 
11700 
34100 
i 6960 
13800 
2510 
2610 
585* 
144* 
800 
14290 
47000 
12300 
35700 
7630 
15230 
2870 
3230 
635t 
173t 
400 
14690 
47100 
12800 
S 36500 
8540 
17100 
3750 
4610 
657 
171 
200 
] 4850 
46600 
13000 
36600 
8860 
! 17700 
4270 
5380 
704 
206 
0 
14920 
46800 
13050 
1 36800 
9030 
' 18200 
4510 
5770 
794 
265 
* 1000 grammes. 
t 600 grammes. 
From H„ = 37 ’4 to Hq = 15'72 the curves for unloading agree, within the errors of 
experiment, with the curves for loading, and oidy a single line is shown in the 
diagram. In the cases of Hq = lO'O and Hq = 5'0 the curves for unloading differ 
from those for loading. The curve for Hg = 5 could not he conveniently shown on 
the diagram. In these two cases there is also an evident want of symmetry, for, if 
the symmetry were perfect, the lines for loading and unloading would cross each 
other on the line of no load. It is interesting to notice how closely the curves for W 
imitate those for Bg. We consider this similarity in § 66 below. 
Experiments on Soft Iron. 
§ 56. A much more extended series of experiments was made upon soft iron wire, 
•0324 sq. centim in cross-section. The wire was “galvanised” when bought, but by 
lieating it to bright redness in a large blowpipe flame all the zinc was burnt off the 
wire and at the same time the wire was annealed. The wire was twisted by means 
of the arrangement described in § 53. The reversing key described in § 31 was used 
in these exjDeriments. 
The first step was to test by the method of § 41 whether X and Y could be 
neglected. The numbers for this S 2 )ecimen, recorded in section (6) of § 41, show that 
X and Y were negligible. 
§ 57. W — t5g Curve for Zero Stress. —To gain a general idea of the magnetic 
character of the wire, a set of observations was made to determine Bg and W for a 
series of values of Hy, the wire having been annealed and being free from strain. 
