548 
PROFESSOR J. A. EWING ON EXPERIMENTAL 
change of dimensions of the piece. For the sake of easy comparison the numerical 
values of & and A and their ratio, k, during the first application of the magnetising 
force, (1) before stretching, (2) after stretching, are given below. The force was 
in each case reversed, reapplied, removed, and reapplied as in former examples: but 
to avoid filling the page with tables of figures it will suffice to refer to fig. 14, 
Plate 59, where the whole experiment is graphically recorded. 
Soft Iron Wire, Annealed and Hardened by Stretching, Plate 59, fig. 14. 
Before stretching. 
After stretching. 
A 
3. 
AT. 
3. 
K. 
0 
0 
_ 
0 
0 
0-07 
2 
0-07 
0 
0 
0-09 
3 
0-14 
0 
0 
0T4 
4 
29 
0-29 
2 
7 
0-28 
10 
36 
0-42 
4 
9 
0-42 
16 
38 
0-70 
7 
10 
0-58 
24 
41 
0-99 
13 
13 
070 
33 
47 
1-44 
21 
15 
0-99 
62 
63 
1-73 
27 
16 
116 
91 
79 
2-14 
41 
19 
1-30 
140 
108 
2-88 
72 
25 
1-44 
195 
135 
3-58 
116 
32 
1-58 
280 
177 
4-20 
167 
40 
1-76 
364 
207 
4-90 
218 
44 
2-02 
468 
232 
5-76 
265 
46 
2-14 
507 
237 
7-20 
359 
50 
2-28 
549 
241 
10-78 
566 
53 
2-51 
614 
245 
1P90 
613 
52 
2-74 
673 
245 
15-20 
751 
51 
2-88 
702 
244 
17-50 
817 
47 
3T6 
764 
242 
23-61 
947 
40 
3-58 
842 
235 
29-81 
1017 
34 
4-20 
926 
220 
35-71 
1078 
30 
5 - 76 
1020 
177 
41-90 
1114 
27 
6-46 
1050 
163 
7-20 
1070 
149 
8 - 64 
1110 
129 
10-26 
1130 
110 
11-91 
1150 
97 
17-50 
1190 
68 
23-61 
1195 
51 
35-71 
1230 
34 
45"51 
1230 
27 
In fig. 14 the curves in full lines, giving the relation of 3 to for the wire before 
stretching, will be readily distinguished from their resemblance to those which have 
already been described and shown in earlier figures. The lower and more sloping 
curves with more rounded outlines, drawn in broken lines, exhibit the behaviour of 
iron which has been hardened by stretching. The effect of stretching is that the 
