406 Proceedings of Royal Society of Edinburgh. [july 18 , 
measure of the Joule effect, a comparison of the deflections (D) 
with the square of the current (C 2 ) was made for several strengths 
Table XIII. 
Temperature. 
Resistance 
of Pile 
+ Galvanometer. 
Whole per cent. 
Increase. 
Mean Increase 
per cent, 
per 1° C. 
8° -8 C . 
2158 
0 
0 
87°'3 
2-186 
1-30 
•0169 
92° -6 
2-187 
1-34 
•0159 
120 ° T 
2-200 
1-95 
•0175 
131°-8 
2-205 
2-18 
•0178 
155 ° *7 
2-215 
2-64 
■0180 
222°‘l 
2-248 
4-17 
•0195 
227 0, 1 
2-249 
4-22 
•0193 
247°'4 
2-261 
4-77 
.0200 
257° -2 
2-267 
5-05 
•0203 
265°-6 
2-271 
5-24 
•0204 
278 ° 1 
2-278 
5-56 
*0206 
of current. Table XIY. gives the results for iron strips. The 
periods were 3 minutes each. As the temperature varied slightly, 
the last column gives ^ corrected for the small changes in re- 
C 2 
sistance and specific heat. That the proportionality of D to C 2 
holds pretty nearly will be seen. 
Table XIY. — Joule Effect compared with (Current) 2 . 
Temperature. 
D. 
C. 
D 
C2 Xl ° 3 - 
D 
coXio 3 
(Corrected to 
15°-8 C.) 
15 ° - 8C . 
1284 
1439 
•6203 
•6203 
16 °- 3C . 
761 
1113 
•6146 
•6134 
15 ° - 8C . 
113 
425 
•6256 
•6256 
15 ° - 30 . 
282 
668 
•6319 
•6331 
Time curves were also drawn for the Joule effect heating, by the 
same method as in the case of the Peltier effect. In Table XY. is 
given a set of the readings for the Joule effect in a narrow copper 
strip. The periods here were 150 half-seconds (instead of 100). 
The curve is number 4 in the diagram. Por convenience of com- 
parison with the Peltier effect curves, the 150-periods have been 
reduced in scale, so as to coincide with the 100-periods of (1), (2), 
