646 BRIDGMAN. 



point of view introduced by Wien, namely in considering the phen- 

 omena of conduction to be primarily determined by the motions and 

 properties of the atoms of a metal, and not by the properties of the 

 swarm of electrons playing in the spaces between inert atoms. I 

 hope to show in a future paper that a somewhat different physical 

 account can be given of the phenomena, still retaining Wien's broad 

 view point, and that the formulas so obtained are somewhat like 

 those of Wien in general character and are in better agreement with 

 the facts. 



Summary. 



In this paper data are given for the change of resistance of 22 

 metals between 0° and 100°C over a pressure range from to 12000 kg. 

 Three of the metals are abnormal; bismuth and antimony both have a 

 positive pressure coefficient, and the pressure coefficient of tellurium 

 has an abnormally large negative value. The other 19 metals have 

 minute differences in their individual behavior, but in broad outline 

 the behavior of all is alike. The pressure coefficient changes very 

 little with temperature, and therefore also the average temperature 

 coefficient changes very little with pressure; this holds over a range of 

 pressure great enough in many cases to compress the metal to less 

 than its volume at 0° Abs. under atmospheric pressure. 



The instantaneous pressure coefficient of all the normal metals on 

 the other hand decreases markedly with increasing pressure. By far 

 the larger number of the normal metals show a decreased relative 

 curvature in the resistance-pressure curve at the higher temperature. 



It is shown that none of the hitherto proposed theories can satis- 

 factorily account for all these facts. The recent attempt by Gru- 

 neisen, however, must be recognized as a promising beginning. 



The Jefferson Physical Laboratory, 

 Harvard University, Cambridge, Mass. 



