This work is part of a more general study of interactions betweenmontmorillonite and organic substances, carried out in connection with thefundamental results of MacEwan and Mackenzie. The object of this work wasthe study of adsorption of acetone in the vapor phase.

Samples of sodium and calcium montmorillonites were placed in pyrex tubesprovided each with a ground glass stopper and a tap. Each tube was joined toa vacuum pump through a desiccating column and heated for several hours to280°C so as to desorb the water contained in the clay and on the glasswalls. At the conclusion of the evacuation, the tube was opened while hot, so as to introduce a recipient containingacetone in solution in castor oil (which had been previously degassed invacuum). The tube was again closed, re-evacuated, cooled, then isolated fromthe vacuum pump and put into a thermostat (40°C).