A Method of Obtaining Air Currents of Different Humidities

Abstract

FOR various experiments in which the change of a physical property with the humidity of the surrounding air has to be studied, for example, the calibration of a hair hygrometer, it is necessary to have some means of producing currents of air of different relative humidities. The usual method of attaining this in practice is to bubble air through wash bottles containing solutions of water and sulphuric acid of suitable strengths. A certain percentage of the acid in the solution gives rise to a certain definite humidity to the air in contact with it, and the bubbles of air through the solution are supposed to acquire this humidity.¹