30 
MR. H. TOMLINSON ON THE INFLUENCE OF STRESS 
Table III. 
Name of metal. 
Elasticity of volume = v 
e 
Alteration of volume 
produced by longi¬ 
tudinal stress of 
1 grm. per square 
1 
centim. • 
3v 
Section in square 
centims. 
3(1 —2<r)’ 
Iron. 
1508 xlO G 
221-1x10-12 
6550 xlO" 6 
Platinum (1) . 
5857 xlO 6 
569-0 xlO" 12 
5178x10-® 
German-silver (1). 
1524 xlO G 
218-7 x 10~ 12 
5731 x10" 6 
Copper (1) . 
1045 x10 6 
319-0 x 10- 13 
7310 x Hr 6 
Copper (3). 
920-3 xlO 6 
362-3 x 10- 13 
18330 x10- 6 
Platinum-silver (1) . 
2190 xlO 6 
152-2 xlO" 13 
7681x10- 6 
Zinc (1)* . 
348-3 x 10 6 
957-0 x 10“ 13 
8144 x10- 6 
Silver (1) . 
930-3 XlO 6 
358-3 x 10- 13 
5464 x10-® 
Aluminium (1). 
316-0 xlO 6 
1055-0 x 10" 13 
8632 xIQ" 6 
Tin (1). 
130-1 xlO 6 
2562-3 x Br 13 
7758xl0- 6 
Lead (1) . 
76-5 xlO 6 
4360-0 x 10- 13 
7374 xIQ- 6 
Remarks on Table III. 
There is little to be said with reference to this table except to call attention to the 
great alteration which takes place in the order of several of the metals, with reference 
to their elasticity of volume, and that occupied by them in the tables of “Young’s 
modulus.” We find, for instance, platinum, which in the latter table stands second on 
the list of annealed metals, here ranking as seventh, whilst the alloys, platinum-silver 
and German-silver, are both higher than iron, the former of the two alloys con¬ 
spicuously so. It would seem, moreover, that either small reliance can be placed on 
the method of determining' the ratio of lateral contraction to linear elongation from 
observations of the longitudinal elasticity and torsional rigidity, or else that the 
volume elasticity varies considerably with different specimens of the same metal; for 
instance, the mean value for the modulus of bulk elasticity in the case of the two 
specimens of annealed copper recorded in the last table is 982 X 10 6 , whereas Thomson! 
gives the corresponding value for copper as 1717 X 10 6 . 
Permanent Alteration op Density produced by Longitudinal Traction.]; 
A few experiments were made with a view to determine the 'permanent alteration of 
density which can be produced by longitudinal traction. Two methods were adopted: 
* Zinc, tin, and lead are, though in the drawn condition, added to this list, as the process of drawing 
had not hardened them in any degree sufficient to make much difference in either the torsional rigidity 
or the modulus of elasticity. 
t ‘ Brit. Encyc.,’ Art.: “ Elasticity,” Table I. 
+ For observations on the alteration of density produced by torsion and hammering, see Part II. 
