348 
.DR. E. H. GRIFFITHS AND MR. EZER GRIFFITHS ON THE 
Table XYI. (continued). 
T. 
0, (obs.). 
(calc.). 
Difference. 
T. 
1 
C p (obs.). 
Cj, (calc.). 
Difference. 
1 II 1 
Cadmium, fiv — 168. 
o 
50 
3-46 
3-60 
- 0-14 
o 
260 
6-14 
6-10 
0-04 
70 
4-58 
4-58 
— 
300 
6-24 
6-19 
0-05 
100 
5-37 
5-26 
0-11 
340 
6-33 
6-27 
0-06 
HO 
5-79 
5-66 
0-13 
380 
6-44 
6-36 
0-08 
200 
5-99 
5-94 
0-05 
Lead, /3v = 92. 
0 
23 
2-96 
3-01 
-0-05 
o 
160 
6-01 
6-03 
-0-02 
28 
3-58 
3-68 
-0-10 
200 
6-10 
6-10 
— 
37 
4 - 50 
4-48 
0-02 
240 
6-18 
6-21 
-0-03 
80 
5-72 
5-66 
0-08 
300 
6-32 
6-32 
— 
120 
5-93 
5-91 
0-02 
360 
6-45 
6-46 
-o-oi 
Sodium, /3i> =180. 
o 
50 
3-50 
3-41 
0-09 
o 
250 
6-41 
6-14 
0-27 
70 
4-43 
4-43 
— 
290 
6-60 
6-26 
0-34 
90 
5-04 
5-01 
0-03 
330 
6-85 
6-35 
0-50 
130 
5-74 
5-57 
0-17 
350 
7-06 
6-40 
0-66 
190 
6-12 
5-94 
0-18 
365 
7-43 
6-44 
0-99 
In the table below the values of v m , which have been obtained from the atomic heat 
formulas, are compared with the values deduced by Debye from the elastic constants 
of the metals. 
v m x 10 -12 . 
Metal. 
Al. 
Fe. 
Cu. 
Ag= 
Cd. 
Pb. 
v m (atomic heat). . . 
8-2 
8-0 
6-7 
4 - 5 
3-5 
1-9 
v m (elastic constants) . 
8-3 
9-7 
6-8 
4-4 
3-5 
1-5 
Attention may be drawn to some of the conspicuous features shown by the above 
comparisons. 
In the first place it will be observed that, with the possible exception of lead, the 
calculated values are too low at the higher temperatures; also that the departure is 
most pronounced where the curvature is greatest; in copper for example, at 130° C. abs. 
and in zinc at 150° C. abs. 
