THERMO-ELECTRIC QUALITY UNDER PRESSURE. 



331 



75°, and the hysteresis is about tlie same fraction of itself, but is in 

 the normal direction. No readjustment was necessary in passing 

 from the constant temperature to the constant pressure cur%es. 



o 



X 



i 30 



o 

 > 



s 



I 

 a. 



40° 60° 80° 

 Temperature Temperature 



Pure Iron Annealed 



-200 

 ^0° 



Figure 28. American Ingot Iron, Annealed. On the left, the heat ab- 

 sorbed by unit quantity of electricity in flowing from uncompressed metal to 

 metal compressed to the pressure indicated on the curves, as a function of 

 temperature. On the right, the excess of Thomson heat in metal compressed 

 to the pressure indicated on the curves over uncompressed metal, as a function 

 of temperature. 



The numerical results are shown in Tables XXVI and XXVII and 

 Figures 27 and 28. The Peltier heat is at first negative at all pressures, 

 becomes positive with increasing temperature, passes through a posi- 



