CAPACITY FOR HKAT OF METALS AT I>Il IT.K'KNT TEMPERATURES. 



177 



Tt will be seen that for the purpose of representing the experimental results, there 

 is little to choose between the two formulae, the greatest difference from our parabolic 

 formula being less than 1 per cent, which NKRNST states to be the probable 

 experimental error in his observations. 



The greatest divergence between NERNST'S results and the modified EINSTEIN'S 

 formula amounts to 1'4 per cent., and it must be remembered that the empirical term 

 bT 3 " in that formula was added as a consequence of these experimental numbers. 



Thus it appears that, in the case of lead, the simple parabolic formula holds over 

 the range 62 C. to 373 C. absolute. 



In the case of silver, NERNST records five observations (column II., iitfrci). 



ATOMIC HEAT. Silver. 



If we consider the group about 200 C., we have the following results : 



At 204 C. absolute- 

 Mean observed value 5'83 



Calculated (EINSTEIN'S modified formula) 5 '80 



(GRIFFITHS' parabolic formula) 5 '84 



Here, again, the conclusions of the different observers are in close agreement. 



At the still lower temperatures, the decrease in the observed values is so marked 

 that, assuming the validity of NERNST'S values, the parabolic formula cannot possibly 

 hold good, and we can only conclude that some marked change takes place in the 

 nature of the curve below 200 C. absolute. 



We hope to investigate the values of the capacity for heat of silver at some 

 intermediate points in the large gap between the groups determined by NERNHT. 



In conclusion, it is notable that, with the exception of three observations upon 

 silver taken at closely adjacent temperatures, all the values obtained by NERNST fall 

 (within the margin of probable experimental error) upon the loci of the parabolas 

 which express our experimental results at higher temperatures.] 



VOL. ocxili. A. 2 A 



