626 



BRIDGMAN. 



are shown in Figure 23 at 0°, 25°, 50°, and 75°, and the numerical 

 values of resistance are given in Table XX. It has already been 

 mentioned that the run at 100° was omitted because the solder alloyed 

 with the bismuth and melted it off. The resistance curves are convex 

 toward the pressure axis; furthermore the steepness increases with 

 pressure faster than the resistance itself, so that the instantaneous 



3 4 3 6 7 8 



Pressure. Kg. /Cm.' X 10' 

 Bismuth 



1 12 



Figure 23. Bismuth, resistance as a function of pressure at several tem- 

 peratures. 



pressure coefficient increases also with pressure. The same abnormal 

 curvature was shown by the two irapurer samples. The numerical 

 values of the average and instantaneous coefficients are shown in 

 Table XXI. The behavior here is exactly the reverse of that of normal 

 metals, for which the pressure coefficient becomes numerically less 

 at higher pressures. The experimental values of the average coeffi- 

 cient to 12000 kg. are shown in Figure 24. 



