MAGNETISATION OF IRON AND OTHER MAGNETIC METALS. 
237 
Steel. 
§ 30. Of the following experiments, Nos. 1 to .3 vvei'e made witli samples of steel 
supplied by Messrs. Jowitt, containing various percentages of carbon. The sample 
was built, in each case, into a bobbin of the form shown in fig. 13, with wrought iron 
Pig. 13. Fig. 14. 
cones. No. 6 was made with a specimen of Whitworth’s fluid compressed steel, 
built with wrought iron cones into the bobbin of fig. 14. Observations were made 
in the strongest fields only. 
Table IX. — Steel of Various Qualities. 
Description of steel. 
Outside field. 
SB — outside field 
SB 
47r 
outside field 
1. Bessemer steel, containing about 
0'4 per cent, of carbon 
17,610 
39,880 
1770 
2-27 
2. Siemens-Martin steel, containing 
about 0'5 per cent, of carbon 
18,000 
38,860 
1660 
2-16 
3. Crucible steel for making chisels, 
containing about 0'6 per cent, of 
carbon 
19,470 
38,010 
1480 
1-95 
4. Finer quality of crucible steel for 
chisels, containing about O'8 per 
cent, of carbon 
18,330 
38,190 
1580 
2-08 
5. Crucible steel, containing about 1 per 
cent, of carbon 
19,620 
37,690 
1440 
1-92 
6. Whitworth fluid compressed steel 
18,700 
38,710 
1590 
2-07 
§ 31,—The following tests were made with a piece of Vickers’ tool steel, built with 
wrought iron cones into the bobbin shown in fig. 15. In this case the magnetising 
field must have been sufficiently uniform to make the first column in the table repre¬ 
sent the last [x, and the second last column 3 very nearly. This steel had great 
coercive force ; the residual magnetic induction (entered in the table under ^I3r) was 
