﻿Kinetic Theory of Adsorption. 



695 



In order to obtain more direct evidence of the validity of 

 the un-approximated formula (11), I have applied it to 

 observations of Travers * on the adsorption of carbon dioxide 

 by charcoal, in which an adsorption 68 per cent, of satur- 

 ation is reached, and to some measurements by Langmuir f 

 on the adsorption of methane and carbon monoxide at low 

 temperatures, in which adsorptions were reached respectively 

 85 per cent., 77 per cent., and 59 per cent, of the saturation 

 values. Fig-. 2, in which log oc/p is plotted against log 

 (1 — «/a'), represents Travers's measurements at — 78°*2 C. 



Fig. 2. 



oo 



Travers's Observations on the Adsorption of Carbon Dioxide 

 by Charcoal at — 78°-2 C. 



In equation (11), if a is put equal to unity, we obtain an 

 equation of the same form as one used by Langmuir in the 

 paper quoted for most of his experiments, and with which 

 he finds good agreement. For three experiments, however 

 (Tables 9, 13, and 16 of the paper quoted), he has to use a 

 more complicated formula based on the assumption of two 

 distinct kinds of points of attachment. Equation (11), 

 which makes no such assumption, is found to fit these 

 results about as well as Langmuir's equation, as is shown in 



* Travers, Proc. Roy. Soc. A. lxxviii. p. 9 (1906). 



t Langmuir, Jour. Amer. Chern. Soc. xl. p. 1382 (1918). 



