240 



BRIDGMAN. 



Now 



= N8* 



and 



/dv\ /dvy 



Hence substituting back, we have 



a 



/'W = " ^2 " ^ 



At zero pressure 



18 KT 



do 



/'(S ) ------ 



So 2 



We have to compare this with the value /'(So) = — 77 , which we pre- 



00 



viously found, neglecting the temperature effect. For the case of 

 copper, I have substituted numerical values into the second member 

 of the right hand side of the last equation, obtaining 4 X 10 -5 , com- 

 pared with the value 2.4 X 10 -3 for a/So 2 . Hence the effect of the 

 temperature term is not important. 



It is also probable that the new term will not greatly affect the values 

 that we have found for /"(So) and /"'(So), or alter the conclusions that 

 we have drawn from these numerical values, because in the case of 

 copper, the numerical value of the new term which stands besides p 

 in the next to the last equation above is 1 X 10 10 , and is nearly con- 

 stant, whereas p varies through a range of 1.2 X 10 10 . 



