160 PROF. E. G. COKER AND MR. K. C. CHAKKO: THE STRESS-STRAIN PROPERTIES 
multiplied by the values of /3 appropriate to the wave-length. Their mean values 
afford measures of the strains as the table shows. 
Table Y.—Values of 
Xx = 20 
= 25 
= 30 
= 35 
= 40 
= 45 
= 50 
1165 
1167 
1180 
1180 
1196 
1201 
1205 
1012 
1000 
1000 
998 
1032 
996 
997 
805 
810 
810 
840 
848 
838 
831 
681 
672 
670 
657 
657 
656 
677 
589 
581 
572 
559 
563 
563 
564 
473 
466 
468 
479 
467 
435 
Total . . . 
8294 
7035 
5782 
4670 
3991 
2353 
435 
Mean . 
1185 
1005 
826 
667 
570 
471 
435 I 
Scale of strains 
■ 1 R 8X 
E ' ' ' SY ‘ 
3-84 x 10~ 3 
3-25 x10- 3 
2-67 x10“ a 
2-16 x10- 3 
1-85 x10- 3 
1 -52 x10- 3 
1-39 x10“ s 
- x 10~ 3 
s 
0-260" 
0-308" 
0-375" 
0-463" 
0-541" 
0-658" 
0-720" 
The data afforded by this method is therefore sufficient to construct a stress-strain 
curve entirely from these measurements of the bands due to retardation in the 
spectrum, and if the assumptions are correct, it ought to agree with a similar 
diagram constructed from data obtained independently. The stress-strain diagram 
Table VI.—Stress-strain Values. 
Xi. 
A.. 
Strains. 
0-002. 
0-004. 
0-006. 
0-008. 
o-oio. 
0-012. 
0-014. 
9 
0*016. 
0-018. 
0-0192. 
20 
4725 
596 
1210 
1815 
2350 
2834 
3290 
3700 
4090 
4420 
4570 
25 
4925 
612 
1205 
1827 
2362 
2830 
3290 
3672 
4015 
4340 
4530 
0 
30 
5135 
620 
1230 
1840 
2360 
2810 
3250 
3620 
3950 
4220 
4340 
<M 
35 
5380 
629 
1258 
1855 
2390 
2850 
3280 
3644 
3980 
4270 
4400 
11 
40 
5660 
631 
1262 
1880 
2424 
2900 
3330 
3730 
4020 
4265 
4360 
£ 
45 
6015 
647 
1271 
1860 
2420 
2910 
3255 
3765 
4130 
4450 
4610 
50 
6430 
654 
1295 
1910 
2440 
2880 
3295 
3695 
4000 
4260 
4370 
Mean . 
627 
1247 
1855 
2394 
2859 
3284 
3689 
4026 
4311 
4454 
