1912] 



on Heai Fi'oblems 



589 



In all instances, however, the atomic heats of the elements fall below 

 the normal valne as the absolute zero is approached. 



The mean specific heats of a few substances, for temperatures 



Fig. 9. 



ranging from 20° to 80° Abs., made with the Hquid hydrogen calori- 

 meter, are given in the following table : — 



Table IV. — Mean Atomic Specific Heats between 20 Deg. 

 AND 80 Deg. Absolute. 



Diamond . . . . . . . .0-05 



Graphite 0-17 



Magnesium . . . . . . . .1-71 



Aluminium . . . . . . . .1-12 



Ice (molecule) 1-94: 



At the mean temperature of 50° Abs. it will be seen that the 

 diamond has a very small specific heat, and all the other bodies in 

 Table IV show a considerable decrease as compared with determina- 

 tions made at ordinary temperatures. The theoretical curve of the 

 change of atomic specific heat due to temperature on Einstein's theory, 



