657 
1907-8.] Young’s Modulus under an Electric Current. 
meet ; it, too, therefore, may coincide with the other graphs, in which case 
ail three would ultimately coincide, and there would he only one value for 
the modulus, no matter what the method of heating be, or the load within 
the limit of elasticity. It would be of interest to find this out, but the 
current at my disposal was not powerful enough to heat the wire to the 
necessary temperature. 
Soft Iron Wire. 
Length = 
Area of cross-section = 
Elongation weight = 
Total load on wire = 
Load per sq. mm. = 
97’92 cms. 
•0005474 sq. cms. 
500 grams. 
800 „ 
14’62 kilos. 
Table I. — First Cycle. 
No. 
Temp. 
Elongation for 
500 grams. 
No. of 
Observations. 
M. 
1 
16*5 C. 
•04839 cm. 
6 
18T4 xlO 11 
2 
18-8 
•05090 
8 
17-25 
3 
23'4 
■04905 
8 
17-90 
4 
29T 
•04736 
8 
18-54 
5 
35-3 
•04592 
8 
19T2 
6 
42-0 
•04465 
9 
19-66 
7 
45-9 
•04412 
1 8 
19-90 
8 
50-6 
•04377 
8 
2006 
9 
54-2 
•04368 
8 
20T0 
10 
59*5 
•04387 
9 
20-01 
11 
65-7 
•04438 
7 
19-78 
12 
74-4 
•04519 
6 
19-43 
13 
85-6 
•04638 
8 
18-93 
14 
100-4 
•04795 
8 
18-31 
15 
110-3 
•04880 
8 
17-99 
16 
120-3 
•04932 
8 
17-80 
17 
114-1 
•04938 
8 
17-78 
18 
105-2 
•04909 . 
7 
17-89 
19 
92-5 
•04838 
8 
18T5 
20 
80-9 
•04754 
8 
18*47 
21 
74-0 
•04670 
9 
18-80 
22 
66-8 
*04576 
8 
19*19 
23 
61-2 
•04544 
6 
19-32 
24 
57-5 
•04566 
7 
19-23 
25 
53-0 
•04635 
8 
18*94 
26 
45*2 
•04780 
8 
18-37 
27 
39-3 
•04899 
8 
17-92 
28 
32-0 
•05034 
5 
17-44 
29 
25-9 
*05125 
8 
17-13 
30 
19-5 
•05186 
8 
16-93 
31 
16-7 
•04828 
8 
18-18 
VOL. XXVIII. 
42 
