The Process of Desiccation of Substances

In making exact wings, the hygroscopic capacity of substances must be continually kept in view. Phosphoric and hydride, a white powder, liquid sulfuric acid, solid and porous calcium chloride, or the white powder of ignited copper sulfate are most generally employed in drying gases. They absorb the moisture contained in air, and all gases to a considerable but not unlimited extent. Water dried by calcium chloride still contains a certain amount of moisture, which it can give up to sulfuric acid. The most complete desiccation takes place with phosphoric and Hydride.