[mclean] 



THERMAL EVOLUTION OF GASES 



75 



Dewar's work was performed with the charcoal at the temperature 

 of liquid air and Titoff's at 0°C. 



Chappuis and Titoff observed that the first portion of the gas to 

 be adsorbed always evolved more heat than subsequent additions. 

 Applying the second law of thermodynamics Titoff found that 



4(logP)=^ 

 dt 



(log X) 



1 . 985 r^ 



where P is the pressure of the gas in equilibrium with a certain ad- 

 sorbed quantity X, T, the temperature, and Q, the quantity of 

 heat evolved if a gram molecule of the gas were adsorbed at the 

 pressure P. Therefore if Q were constant and if log P were plotted 

 against log X at difïerent temperatures, the curves so obtained for 

 two different temperatures should be equidistant from one another 

 for all values of X or P. But if Q is not constant, but greater for 

 lower than for higher values of X, as is usually the case, then the 

 curves ought to be further apart for lower values of A' than for higher. 

 Titofif found this to be the case. 



The object of the experiments to be described below was to 

 measure the heat developed when a number of gases were adsorbed 

 by difïerent samples of charcoals and carbonized lignites and to 

 account for it. 



Tol^jcuum 



F/g I 



