290 



BRIDGMAN. 



temperature and resistance of this new sample was sensibly linear 

 within the range 0° to 100°, 



The thermo-electric behavior of a thallium-lead couple at atmos- 



40° 50° 60° 



Temperature 

 Thallium 



Figure 4. Thallium. Thermal E.M.F. of a couple composed of one branch 

 of uncompressed metal, the other compressed to the pressure in kg./cm.- 

 indicated on the curves, the junctions being at 0°C and the temperature 

 plotted as abscissae. 



pheric pressure is represented within the limits of measurement by 

 the formulas 



E = (1.659 f-0.00134 ^--0.0000050 f) X 10~« volts, 



P = (1.659-0.00268 i-0.0000168 f-) (t + 273) X 10"« volts, 



a = (-0.00268- 0.0000336 f) {t + 273) X lO'^ volts/°C. 



The pressure measurements were very satisfactory. The effect 

 is large and positive, equilibrium was quickly reached, the readings 



