156 



BRIDGMAN. 



50°, 75°, and 99°, and at the same temperature intervals there were 

 also made two sets of readings of resistance as a function of tempera- 

 ture at atmospheric pressure, which agreed within the sensitiveness of 

 setting the slider of the bridge. The accuracy of the pressure readings 

 was as follows: at 0° the average arithmetical departure from a smooth 

 curve (no discards) was 0.41% of the maximum pressure effect, at 25° 

 (no discards) 0.32%, at 50° (one discard) 0.16%, at 75° (no discards) 

 0.34%, and at 99° (no discards) 0.24%. The average departure from 

 linearity at the maximum was 0.9% of the maximum pressure effect. 



TABLE II. 



Nickel. 



The numerical results of the measurements are reproduced in 

 Table II and Figure 2. The method of computation and presentation 

 is the same as that used in the preceding papers. 



Compared with the previous results on less pure nickel, the pressure 

 coefficient of this is on the average about 15% higher, again verifying 

 the observation that in most cases impurity depresses the pressure 

 coefficient, but by a less amount than the temperature coefficient. 

 The temperature coefficient of this piece is 0.00634, against 0.00487 

 of the previous sample, or an increase of 30%. The pressure coeffi- 

 cient of this new sample increases with rising temperature, as did that 

 of the other sample, but the increase is much less rapid, and is not 

 linear, becoming less rapid at the higher temperatures. The devia- 

 tion from linearity of this new sample increases linearly with rising 

 temperature, whereas that of the less pure sample at first passed 



