1887.] Mr A. Campbell on Measurement of Peltier Effect. 401 
D 
Ct 
= A + B£. 
Now by careful measurements (heating a junc- 
tion, &c.) the thermoelectric power of the FeArg was found to be 
cpiite constant throughout the range of temperatures used. The 
FeZn line also was found to be straight. Therefore some other cor- 
rection (possibly for conduction) would have to be introduced if 
these measurements are to agree, in this respect, with the received 
theory. 
Table X. 
Tempera- 
ture. 
D 
Ct 
Observed. 
D 
Ct 
Calculated. 
Tempera- 
ture. 
D 
Ct 
Observed. 
D 
Ct 
Calculated. 
X 
11°'4 C. 
1613 
1599 
X 
74° -3 
1304 
1322 
Y 
1 1° *6 
1599 
1599 
X 
81°-0 
1275 
1279 
X 
38° T 
1461 
1515 
Y 
106°-8 
1079 
1080 
Y 
38° -8 
1474 
1510 
X 
109 o, 0 
1053 
1061 
X 
39°-7 
1455 
1508 
Y 
116°*6 
1039 
993 
X 
72°-9 
1332 
1332 
Y 
143° -7 
739-8 
722 
Y 
73° *1 
1333 
1330 
X 
144°-0 
722-6 
718-4 
Table XI. 
Tempera- 
ture. 
D 
Ct 
Observed. 
D 
Ct 
Calculated. 
Tempera- 
ture. 
D 
Ct 
Observed. 
D 
Ct 
Calculated. 
X 
8° -9 C. 
1533 
1533 
Y 
129°-1 C. 
699-3 
665-9 
X 
11°T 
1523 
1525 
X 
163°-7 
254-9 
250-0 
X 
59° -0 
1269 
1280 
Y 
161°-3 
251-3 
281-2 
Y 
60° -0 
1283 
1274 
Y 
172° -8 
147-9 
128-3 
X 
61°-1 
1280 
1267 
X 
l74°-2 
96-9 
99-1 
X 
95°-3 
1009 
1001 
X 
180° -6 
11-4 
19-8 
Y 
96° -0 
988-6 
995-0 
Y 
183°'2 
0 
- 17 T 
X 
96°-4 
978-6 
990-5 
X 
l83°-2 
- 28*4 
- 17-1 
X 
129° -5 
703-9 
661-5 
X 
191°-5 
- 123-7 
-163-2 
The values of in Table X. agree approximately with the 
formula 
D 
Ct 
= 1622 - 1-590(9- -O3230 2 , 
where 6 = temperature centigrade. 
The fourth column in Table X. gives the values calculated from 
this formula. 
This would make 
D 
Ct 
vanish at 200° *8 C. and 
at - 250 o, 0 C. Now, the directly measured neutral point of the 
FeZn used is 196°*9 C. 
