10 
MR. H. TOMLINSON ON THE INFLUENCE OF STRESS 
Experiment V. 
Annealed iron wire which had been very heavily loaded and unloaded a great many 
times on different days previous to this last experiment. 
No. of kilogs. used 
for load. 
Scale reading on 
loading by 4 kilogs. 
at a time. 
Scale reading on 
unloading by 4 kilogs. 
at a time. 
Difference. 
0 
2L22 
21-22 
•oo 
4 
18T0 
18-00 
•10 
8 
15-20 
15-01 
•19 
12 
12-38 
12-10 
•28 
16 
9-45 
9-22 
•23 
20 
6"50 
6-50 
•oo 
This last experiment shows very clearly that the wire does not recover itself until 
all the load has been removed. Also in Experiment IV. we see that a certain amount 
of set disappears even with the removal of the comparatively small load of the scale- 
pan. 
With most of the other metals the recovery of elasticity is much less marked after 
the first hour than is the case with iron. 
The following experiments were made with a soft copper wire ’81 millim. in 
diameter and 630 centims. in length:— 
Experiment VI. 
The wire was loaded for a few minutes with a weight slightly over 8 kilogs., and, 
on the removal of stress, the following observations were made :— 
No. of kilogs. 
Time after permanent 
elongation. 
Leading of scale. 
Alteration of length. 
8 
4 minutes 
5-80 
0 
6 „ 
19-45 
-13-65 
8 
8 „ 
•5"95 
+ 13-50 
0 
10 „ 
19-10 
-1315 
8 
12 „ 
5-80 
+ 13-30 
0 
14 „ 
18-80 
-13-00 
8 
16 
5-75 
+ 13-05 
0 
18 „ 
18-70 
-12-95 
8 
20 „ 
5-68 
+ 13-02 
0 
99, 
18-60 
-12-92 
8 
17 hours 
5-65 
0 
17 hours 2 minutes 
18-50 
-12-85 
8 
4 
^ 95 
5-60 
+12-90 
A great part of the gradual increase of elasticity here observed is due to loading 
and unloading, and a similar effect may be observed in Experiments II. and III., but 
