Abstract
By use of a microcalorimeter of the Calvet type, measurements of the heats of adsorption of water vapor on sodium chloride of large specific surface have been made, after submitting the salt to an electrodeless high-frequency discharge. The results are compared with those previously obtained when working with normal sodium chloride. It is established that the adsorption process is much longer than in the former case and that the heats evolved in, and quantities of water required for, the process of hydration are several times greater than those previously obtained. The appearance of electrical charges on the “blue” salt, after hydration, is established qualitatively.