temperature, corrected for the loss of heat during the period of heating-, 

 was 2,22 degrees K. whilst the quantity of heat, necessary to heat the 

 little steel cylinder with the thermometers 2,22 degrees, amounted to 

 0.11 cal, (result of a separate experiment). Control experiments showed 

 that the heating wire (used as a thermometer) and the thermometer 

 wire outside the steel cylinder liad the same temperature. The mass 

 of the mercury was 314 grammes, so that 0,00142 cal. /degree K. was 

 obtained for tlie mean speciüc heat between 4°, 26 K. and 6",48 K. 



w 

 The relation of Grüneisen \) —-- c^, would ^) have given c^,=0. 0037, 



for 4°.27 K. 



Measurement at 3°. 5 K. Afterwards the experiment was repeated 

 at the temperature of liquid helium, boiling under a pressure of 6 cm. 

 of mercury; 0.000534 cal. /degree K. w^as found for the mean specific 

 heat between 2°93 K. and 3 97 K. 



Assuming this mean value of the specific heat, we shall calcuUxte 

 now the value of this quantity for a definite temperature according 

 to Debije's formula, which holds for our very low temperatures 



C=:C .T\ 



so that the mean specific heat between two temperatures T^ and 

 T, is 



We obtain from the two experiments C=: 0.0000088 and 0.0000127 

 respectively. 



The agreement is not satisfactory ; although, taking into account 

 that the absolute temperature occurs in the formula in the 4*'^ power, 

 and that therefore small deviations in T involve very large ones 

 in C, we may safely conclude from our experiments, that, ivitli 

 respect to the specific heat, nothing peculiar happens at the point of 

 discontinuity, and that we may content ourselves with a preliminary 

 mean value C=: 0.0000110, when we assume for the moment that 

 the specific heat does not show any discontinuity at all. 



We have then 



c= CT' = 0.0000110 T' 



or for a gramme-molecule 



c = 0.00220 T\ 

 For the characteristic constant <9, introduced by Debije we find 



1) E. Grüneisen, Verb. d. Deutschen Phys. Ges. 1913 p. 186. 

 ~) Compare Kamerlingh Onnes and Holst, Leiden Comm. N^. 142a Proceed. 

 June 1914. 



