Magnetic Permeability of various Alloys of Iron. 
69 
stamped on each specimen so as to avoid mistakes and facilitate reference. 
These marks also give some indication of the history of the specimens: thus a 
series of similar numbers but with different letters attached, e.g. 1167 D, 1167 H, 
1167 I, tell us that it is the same batch of ‘‘ steels,” with different proportions of 
the added element or elements :— 
Description. 
1. Carbon steels, 
2. Manganese steels, . 
3. Nickel 3 
4. Tungsten a 
Group. Description. 
9. Nickel—Copper steel, 
10. 5) 
iL, 5 Silicon 3 
12. 5 Manganese ,, ; 
13. Manganese—Chromium steels, 
14. va Tungsten 
15. ms Silicon 
Group. Description. 
Chromium steels, 
23. Cobalt—Manganese—Silicon steels, 2 
24. Nickel—Manganese—Copper steel, 1 
25. Chromium—Tungsten—Copper ,, 1 
26. Chromium—Manganese—Silicon ,, 1 
Crass I. 
No. of 
Specimens. Group. 
13 5. 
18 6. 
12 7. 
4 8. 
Cuass II. 
No. of 
Specimens. | Group. 
1 16. 
6 MWe 
5 18. 
9 19. 
4 20. 
4 21. 
2 22. 
Crass III. 
No. of 
Specimens. Group. 
27. 
28. 
JPA EyIE Il, 
Description. 
Aluminium steels, 
Silicon a 
Chromium __,, 
Copper 3 
Description. 
Manganese—Copper steels, 
Chromium—Aluminium steels, 
i Silicon an 
55 Copper steel, 
*; Tungsten ,, 
Aluminium—Copper _,, 
5 Silicon ,, 
Description. 
Nickel—Manganese 
Silicon steel, . 
Copper—Manganese—Chromium 
steel, 
ELECTRICAL ConpucCTrIVITY. 
Method of Measurement. 
No. of 
Specimens. 
3 
) 
No. of 
Specimens. 
—- HS = & CO 
No. of 
Specimens. 
Aluminium— 
As the rods were about half a centimetre diameter and a little over a metre 
long, the ordinary method of determining the resistance was unsuitable; aceord- 
ingly the potential method of measuring conductivity was employed. Hach 
specimen was compared with a standard of pure copper, of high and known con- 
ductivity, and also subsequently with a standard iron rod, of the purest com- 
mercial iron obtainable. 
A complete analysis of this standard iron (an excellent 
M 2 
