er kiln-drying, and the necessity for getting
material dry as quickly as possible from the saw, for shipping
purposes and also for manufacturing, are bringing about a realization
of the importance of a technical knowledge of the subject.

The losses which occur in air-drying wood, through checking, warping,
staining, and rotting, are often greater than one would suppose. While
correct statistics of this nature are difficult to obtain, some idea
may be had of the amount of degrading of the better class of lumber.
In the case of one species of soft wood, Western larch, it is commonly
admitted that the best grades fall off sixty to seventy per cent in
air-drying, and it is probable that the same is true in the case of
Southern swamp oaks. In Western yellow pine, the loss is great, and in
the Southern red gum, it is probably as much as thirty per cent. It
may be said that in all species there is some loss in air-drying, but
in some easily dried species such as spruce, hemlock, maple, etc., it
is not so great.

It would hardly be correct to state at the present time that this loss
could be entirely prevented by proper methods of kiln-drying the green
lumber, but it is safe to say that it can be greatly reduced.

It is well where stock is kiln-dried direct from the saw or knife,
after having first been steamed or boiled--as in the case of veneers,
etc.,--to get them into the kiln while they are still warm, as they
are then in good condition for kiln-drying, as the fibres of the wood
are soft and the pores well opened, which will allow of forcing the
evaporation of moisture without much damage being done to the
material.

With softwoods it is a common practice to kiln-dry direct from the
saw. This procedure, however, is ill adapted for the hardwoods, in
which it would produce such warping and checking as would greatly
reduce the value of the product. Therefore, hardwoods, as a rule, are
more or less thoroughly air-dried before being placed in the dry kiln,
where the residue of moisture may be reduced to within three or four
per cent, which is much lower than is possible by air-drying only.

It is probable that for the sake of economy, air-drying will be
eliminated in the drying processes of the future without loss to the
quality of the product, but as yet no method has been discovered
whereby this may be accomplished.

The dry kiln has been, and probably still is, one of the most
troublesome factors arising from the dev