8 
MR. H. TOMLINSON ON THE INFLUENCE OF STRESS 
Experiment IV. 
The wire having been left for two days without weights or scale-pan was again 
tested with the pan on. 
No. of kilogs. on pan. 
Reading of scale. 
Alteration of length. 
Mean values. 
0 
3-30 
4 
11-58 
+ 8-28 
J 8-23 
0 . 
3-35 
- 8-23 
Scale-pan removed for 1 minute and then re 
olaced. 
0 
3-30 
8 
0 
19-80 
3-38 
+ 16-50 
-16-42 
j 16-42 
Pan again off and on. 
0 
3-30 
12 
28-10 
+ 24-80 
0 
3-40 
-24-70 
Pan off and on. 
0 
3-30 
Here we see that the effect of the first 4 kilogs. is represented by 8'23, the second 
four by 8'19, and the third by 8‘28. 
As it had been found by preliminary experiment that the density of the wire was 
not permanently decreased to any extent which would introduce an appreciable error 
by supposing it to remain constant, we can easily make the different experiments 
comparable with each other by assuming that the permanent change of section is 
proportional to that of the length. If we do so we arrive at the following results 
No. 
of experiment. 
Temporary alteration 
of length produced 
by the load. 
Load in kilo 
f 7-95 
I. 1610 
L 24-35 
4 
8 
12 
g- a - 
Average alteration 
per 4 kilogs. on unit 
of area.* 
Mean alteration per 
4 kilogs. in each 
experiment. 
7"95 
8'05 
8-12 
8-04 
II. 
8-16 
16-81 
26-01 
4 
8 
12 
816 
8-41 
8-67 
8-41 
HI. 
8-11 
16-70 
26-05 
4 
8 
12 
8-11 
8-35 
8-68 
8-38 
IV. 
7-85 
15-66 
23-56 
4 
8 
12 
7-85 
7-83 
7-85 
7-84 
* Tlie unit of area is supposed to be that of the section of the wire in I.; the length tested was the 
same in all the experiments. 
