146 
PHYSICS: E. H. HALL 
Proc. N. a. S. 
When q is made larger than 1.5 but smaller than 6.5, negative values 
of C result, in all five of the metals, so far as I have examined the matter. 
The following tables represent my results for all of the elementary metals 
for which Bridgman gave the values of a in the paper already referred to. 
A dash ( — ) in place of a number indicates that the number would be 
negative, and that a negative value in this place is regarded as impossible. 
The values of {kf -f- k) at 100° are found by use of equation (10). 
The bo of these tables is the "ionizing potential" needed for dealing 
with the attraction which an electron must overcome in the process of 
ionization. If this ionizing potential is 1 volt, for example, the internal 
work of ionization is about 11700 R ergs per electron. The external 
work of ionization, to provide the kinetic energy and the pv energy of the 
gaseous state, is 2.5 RT ergs per electron. This at 0° would require an 
ionizing potential of about 0.058 volt, which must be added to the bo 
of the tables in order to get the total ionizing potential in volts. 
The general significance of these tables can be illustrated as follows, 
with numbers taken from table 1 : If in cobalt the value of C is 30%, 
the Thomson effect heat, as found by Bridgman for this metal, can be 
accounted for either by 
taking q = 2,bo = 0.02, Ci = 457 X 10 -^ Q = 0, 
or by 
taking g = 3, 5o = 0.01, Ci = 915 X 10-^ Ci = 0. 
In the first case {kf -^ k) will be 0.346 at 100°, while in the second case it 
will be 0.392. If the value of C is 40%, there are corresponding values of 
q, bo, etc., that will account for a. A like statement would hold for any 
value of C between 30% and 40%, and for numberless other values of 
this ratio. 
First Group: Metals for which K i>0 and K 2 = 0 
TABLE 1: COBALT. 
Ki = 7.8, K2 = 0, C2 = 0 
C, or 
Ci 
= 228X 10-6 
Ci 
= 261 X 10-6 
Ci 
= 305 X 10-6 
Ci 
= 457 X 10-6 
Ci 
= 915 X 10-6 
ikf-^k), 
at 0° 
e 
at 100° 
e 
at 100° 
a 
{kf-^k) 
at 100° 
Q 
at 100° 
Q. 
ikf-^k) 
at 100° 
0.01 
0 
.03 
.033 
.5 
.02 
.036 
1 
.01 
.041 
2 
3 
0.081 
0 
.5 
1 
.00 
.111 
2 
3 
0.20 
0 
.5 
1 
2 
.01 
.246 
3 
0.30 
0 
.5 
1 
2 
.02 
.346 
3 
.01 
.392 
0.40 
0 
.5 
1 
2 
.03 
.446 
3 
.02 
.492 
1 If there is any combination of q and 5o that will make C = 0.10 for cobalt, the g 
must be very near 1.5. 
