152 



BRIDGMAN. 



where a is atomic amplitude, and C^ specific heat at constant vokime 

 per unit volume. It is therefore necessary to know the thermal 

 expansion and specific heats of the new elements. Unfortunately 

 the data are not known for a number of the metals of this work. The 

 computation has been made for all those normal substances for which 

 the data are available, and the results are collected in Table XXII. 



TABLE XXII. 



Comparison of the Changes under Pressure of Resistance and Amplitude of 



Atomic Vibration. 



In this table are included the recomputed values for Mg and W. 

 The best agreement is for liquid bismuth. In nearly all the other 

 cases the computed value is much loAver than the observed. This is 

 a reversal of the behavior shown by the previous substances, for which 

 in the majority of cases the computed value was too high. 



The table seems to show no essential difference between a solid 

 and a liquid metal as far as the connection with amplitude goes. 



There seems to be no reason to modify the previous conclusion, 

 Xvhich was that in a large way the changes of amplitude of atomic 

 vibration are an exceedingly important factor in affecting changes of 

 resistance. Superposed on this large effect common to all metals, 

 are specific effects, such as peculiarities of atomic structure or arrange- 



