Year: 1870

The thorough drying of lumber is one of the
most important points in making durable struct-
ure Of wood for indoor or outdoor use and
without doubt for most species of timber it il
best accomplished, all things considered, by pill
ing it IN such way that currents of air may
freely pass through the insterstices and covering
1T so that rains may not wet it.


There are, however, many species of timber
among which may be mentioned the wood ol
some OF our American elms, which season very
slowly by the natural drying process, and many
kinds of timber may be dried much quicker by
artificial means.


1t should be borne in mind that the natural
moisture sap of the wood is solution of va
riOus substances in water, and that it is incosed
in minute capillary cells and tubes which strongly
attract and hold it, when in immediate contact
with IL, but exert this attraction only at an in
sensible distance, SO that when the fluid they
contain is removed they will not, by virtue of
their structure, Te-absOrb moisture, unless again
brought in contact with it.


Most woods are, however, more or less hygrO-
scOpic, and shrink or swell with the dry or moist
condition of the atmosphere. 1t follows from
this that no wood unprotected by paint or var
nish can long remain much dryer than the condi-
tion Of the atmosphere around it admits.


Bot the sensible moisture of the air decreases,
all other things being equal, as its temperature
increases, and substances having affinity for
moisture will absorb retain much less moisture
from the atmosphere at elevated temperatures.
Ii common HOUSES neat
is used, work upon this principle, and are, for
the most part, very satisfactory in their operation
as they can be made of any extent, and large
quantities of material may be seasoned by their
use.


Small quantities of timber may. however, be
quickly and thoroughly seasoned by steaming-
The philosophy of this process-which, if prop
erly performed, does not injure the strength or
durability of the timber-is very simple. a very
Large percentage OF the sap IN all kinds OF wood
Is water. This water, heated to boiling, expands
sixteen hundred and fifty times 1t follows that
if wood be heated to 2I2S, the boiling point of
water, che capillary cells can contain only one
sixteen hundred and fftisth as much water as at
ordinary temperatures, the expanded water es-
Gaping as steam. The proportion of moisture let
IN the wood Is, after stelmIng, less than that de-
manded by it's ordinary microscopic condition.
At least have found it so for certain species OF
hickory and white ash, which increased In weight
after being removed from the steamer and their
surfaces had become dry y


The steaming should be done gradually-tfnt
Is time should be given for the wood to gradually
rise in temperature, and so that the sap may es-
cape gradually from the cells without rupturing
them by it's expansive force when converting
them into steam.


\ cylinder, made of galvanized iron, with riT-
tied and soldered joints, makes q cheap and good
steamer The steam should be generated IN a
sniAole DOller and allowed TO escape at two or
tnree pounds pressure, which, as we have said =,
should be gradually reached in proportion to the
SIZE OF the pieces which it is desired to season.
Ihe wood should De heated throughout its mass
70 Il and remain 50 for little time. II may
De then put aside for use, and will be found fit to


1a IN from one to three days, according to its


a steamer may also be made of wood, with
caulked joints, which will answer the purnose
very well Such steamers have Ione, h., s''
Ployed In steaming wood for bending in carriage
makingi etc, and most carriage shO1s are alrra3v
provided with such apparatus


Should any OF our correspondents know of any
better way TO season timber quicker than the one
we have described, We shall be glad to hear from
them.-S5sHfifc american.