In some cases abroad paper is glued on to all the surfaces of valuable exotic balks.

Other substances sometimes employed for the purpose of sealing the wood are grease, carbolineum, wax, clay, petroleum, linseed oil, tar, and soluble glass.

In place of solid beams, built-up material is often preferable, as the disastrous results of season checks are thereby largely overcome or minimized.
TEMPERATURE The effect of temperature on wood depends very largely upon the moisture content of the wood and the surrounding medium.

If absolutely dry wood is heated in absolutely dry air the wood expands.

The extent of this expansion is denoted by a coefficient corresponding to the increase in length or other dimensions for each degree rise in temperature divided by the original length or other dimension of the specimen.