320 



DIRECT PROPERTIES OF MOLECULES 



116 



found the value 1-24; Olszewski 1 has likewise determined 

 the density of nitrogen at - 181 as from 0-859 to 0-905, 

 and that of marsh gas at 164 as 0-4148. And, finally, 

 Dewar 2 obtained for the density of liquid hydrogen at its 

 boiling-point, 238, the sixfold smaller value 0-07. 



With these values of the density S for the substances in 

 the liquid state I have combined the numbers giving the 

 density A in the gaseous state, and from their ratio I have 

 calculated the coefficient of condensation 



I have, however, not employed the observed values of the 

 density A of the gases, but their values as theoretically 

 calculated from their molecular weight M by means of the 

 formula 3 



A= M/ (28-88x773-3). 



I consider this procedure the more correct as it gives the 

 smallest values for A, and therefore also the smallest possible 

 values for the coefficient of condensation t>. 



In order to now find from these values of t> the values 

 of the diameter s I have employed the numbers for the free 

 path L which I have deduced from Graham's observations 

 and have tabulated in 79. The following table contains 

 the results of this calculation : 



1 Wied. Beibl. 1886, x. p. 686. 



2 Proc. Chem. Soc. 1898, p. 146 ; Wied. Beibl. 1898, xxii. p. 515. 



3 Lothar Meyer, Mod. Theor. d. CJiemie, 6. Aufl. Breslau 1896, p. 36. 



