426 
we eau have. It has already been found that the conductivity of heat 
and electricity is a periodie function of the atomic weights of elements 
and now it is seen tliat the temperature coëfficiënt of eleetric con- 
ductivity of metals is also a periodie function of the atomic weights 
and as the two properties, as has been already observed, are very 
much related, it seeins very probable that the temperature coëfficiënt 
of the conductivity of heat of elements would also be a periodie 
function of their atomic weights. 
Torsional rigidity, Young’s modulus and their temperature coef- 
ficients. 
The following table is obtained from Landolt and Börnstein’s 
Metals 
E 
A i 
T 
£'2 
Al 
6570 
21.3 
2580 
24.7 
Pb 
1493 
- 
550 
78.7 
Cd 
7070 
- 
2450 
46.7 
Cs 
- 
- 
180 
Fe 
18347 
2.25 
7337 
3.04 
Au 
7580 
- 
2850 
3.01 
K 
- 
- 
- 
150 
Cu 
9897 
3.63 
3967 
4.49 
Li 
- 
- 
- 
120 
Mg 
4260 
- 
1710 
30 2 
Na 
- 
— 
- 
130 
Ni 
20300 
2.46 
7820 
3.28 
Pd 
11284 
1.98 
4613 
2.7 
Pt 
16029 
0.73 
6594 
1.78 
Rb 
- 
- 
- 
170 
Ag 
7790 
7.65 
2960 
8.21 
Bi 
3190 
- 
1240 
- 
Zn 
10300 
- 
3880 
— 
Sn 
5410 
- 
1730 
82 
Tabellen. E represents the Young’s modulus, its temperature 
coëfficiënt. T indicates the values of torsional rigidity and A s its 
temperature coëfficiënt 
