DEAL, a thin kind of fir-planks, of great use in carpentry. They are formed by sawing the trunk of a tree into a great many longitudinal divisions, of more or less thickness according to the purposes they are intended to serve.
A very good method of seasoning planks of deal and fir is to throw them into salt water as soon as they are sawed; and keep them there three or four days, frequently turning them. In this case they will be rendered much harder, by drying afterwards in the air and sun: but neither this, nor any other method yet known, will preserve them from shrinking.
Rods of deal expand laterally, or cross the grain, in moist weather, and contract again in dry; and thence have been found to make an useful hygrometer.