882 



greatest ditferences with Henning are about 0.02°, v. Siemkns's 

 measurements diftering a little mure at the lower temperatures, not 

 more than 0.06° however. 



For nitrogen we can also compare our measurements with those 

 by V. Siemens; here again the ditference is very small at the higher 

 pressures and increases as the temperature falls. 



At the higher temperatures our measurements agree hut moderately 

 with those of Crommei,in '), even if we discard his lowest point which 

 he himself considers less accurate. 



The \alues which we oi)tain for the vapour-pressures of pure 

 nitrogen by extrapolating the measurements with the ai-gon-nitrogen 

 mixtures are in good agreement with our direct observations. 



Argon has also been investigated by Ckommeun') in the same 

 temperature-range. His results correspond very well to ours. 



There is only a small difference as regards the triple point. As 

 we made a number of observations in the immediate neighbourhood 

 of this point (fig. 2) and as our points fall very accurately on the 

 curve drawn through the other points determined by Crommelin, 

 we think it probable that the triple point as determined by us is 

 to be preferred. The ditferences are for the rest of the order of 

 magnitude of the errors of observation. 



2,8000 



2/000 



Fig. 2 



1) G. A. Crommelin. Coram. Leiden N". 145d. 

 ") C. A. Crommelin. Coram. Leiden W. 138Ö. 



