IMPROVEMENTS IN PRESERVING WOOD FROM DECAY
Year: 1853

page_text: PROVISIONAL SPECIFICATION left by John Bethell at the Office
of the Commissioners of Patents, with his Petition, on the 1st
March 1858.
(Void by reason of notice to proceed not having been given within the
time prescribed by the Act.)
I, JOHN BETHELL, of No. 8, Parliament Street, Westminster, Gen-
tleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PRESERVING WOOD FROM DECAY" to be as follows :—
My improvements in preserving wood from decay consist, as to one
part thereof, in first charging the wood with either or any of the
solutions of mineral or other salts which have hitherto been used for
such purposes, some of which are described in the Schedule No. 1,
below; then drying the wood by artificial heat in a proper drying house,
so as to expel out of it the water which held such salt in solution, and
then steeping it, after it is so dried, in or covering it over with a water-
proof material, so as to prevent, as much as possible, water or moisture
from being afterwards absorbed by the wood. As to the other part of my
Invention, I claim as part of my improvements the use of sulphate of
zinc for preserving wood. The preservative action of all the mineral salts
dissolved in water which have been hitherto used is generally attributed
by chemists to their power of coagulating the albuminous matters in.

page_text: the sap of wood; but, when used in practice, they are necessarily dis-
solved in a large quantity of water; and when this solution is forced into
wood, the salt quits the water which holds it in solution to combine
with the sap, and leaves the water free in the pores, to act on the fibres
of the wood and seriously to injure them. Whereas by my improvements
the sap of the wood is rendered inert by the action of the salt, and then
all the surplus water or moisture is dried out of it; and the wood, being
then covered with a waterproof material, is prevented from absorbing
moisture again, and will be rendered more durable. In using this
process, I first charge the wood, by any of the processes now well
known, with as much of the solution of the salt as it can be made to
absorb; and for that purpose I prefer using the salts described in
Schedule No. 1, below; and I then place it on trucks, and run it into a
drying house, which is constructed in such a manner that all the smoke
and gaseous products evolved by the combustion of the fuel passes
through the house and between the pieces of wood, so as to dry and
smoke them, and which smoke also tends to preserve the wood. In some
cases I heat this drying house with heated steam, that is, steam which is
heated by being passed through hot pipes or over heated surfaces, and
then it passes through the house and between the picces of wood to
dry and season them. When the wood is sufficiently dried and smoked
(and the time for doing which will vary according to the size of the
pieces of wood and its quality), it is withdrawn from the drying house,
and either plunged into a tank or cistern filled with either of the mate-
rials described below in Schedule No. 2, according to the purpose to
which the wood is going to be used, or the wood may be brushed over or
painted over with such materials.

page_text: Chloride of zinc: one pound of this material, in its concentrated
mucilaginous state, dissolved in 70 pounds of water.
Sulphate of copper: one pound of the crystalized salt dissolved in 80
pounds of water.
SCHEDULE No. 2.
Tar of any kind, either vegetable or mineral, or melted pitch, or
melted bitumen, or melted rosin, or any description of paint or varnish,
or a solution of pitch or rosin, or caoutchouc, or gutta percha, in any
spirit or oil, as linseed oil, or any combinations or mixtures of these
materials, or of any other materials that will make waterproof covering
to the wood.
I claim, as to one part of my Invention, the preserving wood by
first charging it with the solution of any salt in water that has the
property of coagulating albuminous matters, such as those described in
Schedule No. 1; then drying it by artificial heat in a drying house, so as
to expel all surplus or uncombined water, and then covering it with
a waterproof covering, so as to prevent the wood reabsorbing moisture,
and for which purpose the materials named in Schedule No. 2, may
be used. I also claim as my Invention the use of a solution of sulphate
of zinc for preserving wood.