172 Proceedings of the Royal Society of Edinburgh. [Sess. 
Summary. 
(1) The adsorption of sulphur dioxide by blood charcoal at —10° C. 
was studied, and measurements were taken of the amount adsorbed, the 
pressure, and the isothermal heat of adsorption at constant volume. 
(2) The adsorption isotherm is a typical vapour adsorption curve, 
and runs the same course as that found by Trouton for the adsorption of 
water vapour. 
(3) The heat of adsorption curve passes through a minimum and a 
maximum, and finally runs parallel to the adsorption axis. A tentative 
explanation of this is offered. 
In conclusion, the author would seek to express his thanks to Professor 
F. G. Donnan, F.R.S., for his advice given in the course of these experi- 
ments which were performed in 1913-14 in the Chemical Laboratories, 
University College, London. 
( Issued separately June 7, 1917.) 
