546 Prof. Trouton and Mr. Rankine: Stretching and 
Fig. 6.—Decrease of Stress at Constant Length. 
oO) 
So 
Sa 
WEIGHT (in grams) 
3 
Ws LIC =px 
159. leg (=p) 
b 
o 
Oo 
“We-6 L6G /L+1) 
ww 
= 
Ss 
W= 3095-56 ? “gle a 
200 
100 
° 10 20 wo a0 50 60 70 80 90. 100 NO (20 
T/ME (in runutes) 
If in each case we divide a by k we get the following 
result :— 
| a 
Number. | a. k. . py 
Toe 716 | —159:1 | —4-49 
| ae 5977 | —13865 | —4538 | 
a os | 512 | —1126 | —4:55 
| 4...) 395 | — 887 | —4-46 
in 
It will be seen that chro alee this range the rate of 
decrease of weight is nearly proportional to the initial weight, 
at equal times from the beginning of the experiment. 
Fig. 7 represents at plotted against time. The curves are 
rectangular hyperbolas with —— es de and t=—1 as asym- 
ptotes. The ordinates at any ae of ¢ are in the proportion 
7: 6:5: 4 approximately. 
3. Rate of Stretching under Constant Stress, and Rate at 
Recovery on Release. 
_ The apparatus used was the same as in Experiment 2, so 
that the temperature, and yielding of support, effects were 
eliminated. Three determinations were made, the stretching 
weight being 700 grams applied for 1, 3, and 21 hours 
respectively in the three cases. The curves (I. -II, 1° obtained 
are given in Plate XIV. 
