2 
: 
7 
ee ae ee 
W. A. Norton—Force of Effective Molecular Action. 355 
tenacious materials we may take, with but little error, 
r 
“Tog 1007" 
For calculating the maximum ordinate we have the formula, 
a 
= With these formule I have calculated the theoreti- 
by experiment ith most of the materials the experimen 
determinations of coefficients of elasticity and tenacity used, 
are known, or the ood rez believe, answer to 
Same specimen; but in the cases of zinc, brass, and tin, the coef- 
ficient of elasticity and the tenacity may have been obtained 
with different specimens. 
Tenacity. 
Material. Coeff. of Elas., E.  aaaee a. Culeukaiads? a. 
Wrought Iron 25,000,000 Ibs. | 55,000 Ibs. 
Teak 2,214,000 “ | 15,000 “ | 14,600 Ibs. 
Locust 1,tob Get age TCL sa © 
0: 1,311,100 “ 8,500 “ 8,170 * 
Scotch Fir 800 © 3.520 * 3,586 + 
ppe 16,447,400 “ | 36,180 “ | 36,460 “ 
Zinc Wire 13,680,000 “ | 22.551 “ |-2%,950 “ 
Brass, cast 9,170,000 18,000 “ | 20,300 
Tin, cast ise a 00R Ce 650 * 7,820 “ 
ree 720,000 “ 1,824; + 1,870 * 
_ It seems from these results that our molecular formula (equa- 
tion 2) enables us to compute the comparative tenacities of ma- 
close approximation to the truth; also that a scale of mo- 
lecular curves may be deduced from it which serves to repre- 
molecular curve for wrought iron is that answering to k= 
12-41 (fig. 2) curve (a). But the laws of variation of the neu- 
tral distance, d, and the maximum ordinate, /, are so nearly 
Constant over a wide range of variation in the value of &, and 
thus of the corresponding molecular curve, that the assumed 
Curve for wrought iron might be considerably changed without 
materially impairing the correspondence between the computed 
and observed tenacities. The exponent of d in the expres- 
en 3°2, varies only from 3:1 to 3-4 over the entire range of 
values of & from 20 to 5-4; and the value of wu in the expres- 
* Each molecule is subject to the action of 
: veral stead of the 
Rearest one only, but the entire force taking effect on it is equal to the effective 
ie 
i 
G 
| 
he 
action of the nearest molecule multiplied by a factor which should be nearly con- 
Stant for different materials. 
