238 
PROFESSOR J. A. EWINf4 A^D MR. W. LOW ON THE 
scarcely constant, even in fields of over 10,000, and 3 appeared to be still increasing 
in the strongest field to which the experiment extended. 
Fig. 15. 
Table X.— Vickers’ Tool Steel. 
Outside field. 
m 
® — outside field 
a? 
at. 
47r 
(S.) 
outside field 
(e.) 
6,210 
7350 
25,480 
1530 
4-10 
9,970 
7670 
29,650 
1570 
2-97 
12,170 
8000 
31,620 
1550 
2-60 
14,660 
8030 
34,550 
1580 
2-36 
15,530 
8030 
35,820 
1610 
2-31 
Taken together, the experiments on steel render it probable that there are specific 
differences in the saturation values of 3 for different steels, smaller values being found 
in high- than in low-carbon steels. This is to be expected, in view of the decidedly 
low saturation value of 3 found in cast iron. 
Manganese Steel. 
§ 32.—At the suggestion of Dr. J. Hopkinson, we have examined the action of 
strong magnetic forces upon the remarkable alloy of iron and manganese lately 
introduced by Mr. R. A. Hadfield, of Sheffield, which has many peculiar mechanical 
and electrical properties.* The experiments of Hopkinson,! Bottomley,| and 
Barrett § have shown that this steel is almost wholly destitute of magnetic suscepti- 
* See Mr. Hadfield’s paper ou Manganese Steel, ‘ Inst. Civ. Engin. Proc.,’ February 28, 1888. 
t “Magnetisation of Iron,” ‘Phil. Trans.,’ 1885, p. 462. 
X ‘ Report of the British Association for 1885,’ jd. 903. 
§ ‘ Roy. Dublin Soc. Proc.,’ vol. 5, 1886, p. 360. 
