In one the absorbent is placed at the bottom, and the substance to be dried above.
Fused calcium chloride is the commonest absorbent; but it must not be used with alcohols and several other compounds, since it forms compounds with these substances.
The same absorbent' quantitatively takes up any halogen and sulphur which may be present.
Large quantities of ground mica are used in the manufacture of wall-paper, and to produce a frosted effect on toys, stage scenery, &c. Powdered mica is also used in the manufacture of paints and paper, as a lubricant, and as an absorbent of nitro-glycerine and disinfectants.
The soil of yards and the floors and walls of houses rapidly become contaminated, and the ideal condition would be to have an impermeable flooring covering the whole area, and supplied with suitable layers of sand, sawdust, peat-moss or other absorbent substances which can be changed at frequent intervals.