532 



^ = 5.792 

 B= 0.9885 



From the value found for B it appears, that ifv as a function of 

 T is nearly a straight line. 



The constant in Eötvös' formula for hydrogen deviates considerably 

 from the value 2.12, found by Ramsay and Shiklds ^) as the average 

 for a number of normal substances. In Table III the values of k^ö 

 for a few of these substances, together with those for some liquid 

 gases, are collected. As observed by Kamerlingh Onnes and Keesom 

 (note 381 Suppl. No. 23), normal substances form a series in this respect, 

 on the whole progressing with the critical temperature (although with 

 deviations which may be ascribed to particularities in the law of 

 molecular attraction, e.g. with oxygen). 



TABLE III. 



A calculation of the constant k' in Einstein's formula ^) 



if^. 



^if,'^ 



--k'{XMi,=i-RT) 



j'= 20.33 



dT J ' H- ^i 

 for hydrogen gives 



7.34 X 10~' 



The fact, that hydrogen appears to have a considerably higher 

 value of k' than that calculated by Einstein for benzene, might, in 

 view of tlie theory underlying the formula, indicate, that the i-adius 

 of molecular action is larger for hydrogen molecules than for sub- 

 stances like benzene. 



1) J. chem. See. 63 (1893); ZS. f. physik. Ghem. 12 (1893). 



2) Ramsay and Shields ZS. f. physik. Ghem. 12 (1893), 15 (1894). 

 '^) Baly and Donnan, Journ. chem. see. 81 (1902). 



*) A. Einstein, Ann. d. Phys. 4. 34, 1911. 



