312 Proceedings of Royal Society of Edinburgh. [sess. 
{Delayed in publication.) 
Change of the Coefficient of Absorption of a Gas in 
a Liquid with Temperature. By Professor Kuenen. 
(With a Plate.) 
(Read January 22, 1900.) 
Bunsen’s classical experiments on the absorption of gases by 
liquids show that the coefficient of absorption in water and alcohol 
between 0° and 20° diminishes as the temperature rises. Bohr 
and Bock 1 found that at higher temperatures the coefficients of 
some gases (hydrogen and probably nitrogen) pass through a 
minimum, hydrogen in water at 60° C., nitrogen not far from 
100° C. These results were not confirmed by Winkler, 2 who 
concluded from his experiments that the coefficient approaches a 
smallest value asymptotically. Recently Estreicher, 3 working with 
Professor Ramsay, found a minimum in the solubility for helium 
in water at 25° C. 
By a letter from Professor Ramsay I was induced to look at 
the problem from the general point of view of mixtures, and 
to consider whether the phenomenon was not connected with the 
approach of the critical region. 4 
Hitherto mixtures of water or alcohol with gases have not been 
investigated up to the critical condition ; instead of these liquids, 
however, we may consider a substance like methyl chloride or 
carbon dioxide, whose critical temperatures are more easily 
accessible, and mixtures of which with substances of low critical 
point have been sufficiently investigated for our purpose. In 
the vast majority of cases, mixtures of two substances of widely 
different critical temperatures and vapour-pressures behave in 
very much the same manner, and from the behaviour of a com- 
bination like methyl chloride and carbon dioxide, 5 or carbon 
1 Wied. Ann., 44, p. 318. 2 Zeitschr. f. PhysiTc. Chemie, 9, p. 171. 
3 Ibid., 31, p. 176. 4 Vide Estreicher, loc. cit., p. 186. 
Kuenen, Communications, Leiden, No. 13, Zeitschr. f. PhysiJc . Chemie , 
4,/p. 673. 
