489 



7 is sufficient to calculate the temperatures from that calibration. 



In Fig. 1 ') the resuüs of our measurements are represented. In 



the upper lefthand diagram the region up to 25° K. is represented 

 on a larger scale. ^) 



Fig. 1. 



The curve has been calculated from Deblte's formula ') with 

 6*^31 5. Debije's formula appears again to be capable of repre- 

 senting the alomic heat over a large region — the ratio of the 

 largest to the smallest value of the measured atomic heats amounts 

 to more than 80 — with a good approximation. 



In table IV we have compared the atomic heats of copper in the 

 region of the liquid hydrogen tempei'atui'es with the T'-law derived 

 by Debije for low temperatures : 



(7,, = 464 1 [- 



') In Fig. 1 the vertical line which indicates T = 80 has been drawn inaccura- 

 tely; it has to be moved 1.25 mm. to the right. [Note added in the translation |. 



2) At 88" K. our results agree fairly well with those found by Nernst i.e., at 

 the lower temperatures (33° - 23° K.) our values are smaller 



S) P. Debue. Ann. d. Phys. (-t) 39 (191ïi), p 789. 



