Plaster for common work is a sort of mortar spread over surfaces to make them smooth. It is laid on in successive coats, the composition of which varies, and is given at pp. 178-179.

Plaster of Paris, or calcined gypsum, is a very quick-setting material, the basis of several cements, for which see p. 178.

Asphaltes are combinations of bituminous and calcareous matter. The best are natural - found chiefly in Switzerland - but there are many artificial imitations made with pitch and chalk.

The material is generally heated, and poured in a molten state over the surface to be covered. Some kinds are laid as powder and compressed by ramming.

The best varieties of asphalte are from Seyssel, and Val de Travers in Switzerland.