applied to a surface in fit condition to receive paint.

The decay of paint is due to chemical change, and nearly all chemical reactions are accelerated by water and heat. It is therefore necessary in designing protective coverings that materials be used which are repellent of moisture and as slightly affected by heat as possible.

To understand the pigment question one needs some knowledge of forces which are insensible at sensible distances, viz., molecular forces, such as surface tension and chemical affinity. All phenomena taking place in paint are due either to physical action (heat, light, electricity) or to chemical action, that is, the tendency of different kinds of matter by interaction to produce new substances.

Andés in his work on Anti-Corrosive