IMPROVEMENTS IN PRESERVING WOOD
Year: 1864

page_text: LETTERS PATENT to John Bethell, of No. 38, King William Street, in
the City of London, Gentleman, for the Invention of "IMPROVEMENTS IN
PRESERVING WOOD."
Sealed the 16th June 1865, and dated the 23rd December 1864.
PROVISIONAL SPECIFICATION left by the said John Bethell at the
Office of the Commissioners of Patents, with his Petition, on the
23rd December 1864.
I, JOHN BETHELL, of 38, King. William Street, in the City of London,
Gentleman, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN PRESERVING WOOD," to be as follows:-
My Invention of "Improvements in Preserving Wood" consists in forcing
into the pores of wood the vapours of all the materials named below in
Class 1 and 2.
In describing these improvements I will first describe the mode by which

page_text: I force into the pores of the wood the vapours; and, secondly, I will describe
how I obtain these vapours, and from what materials.
First, in carrying out this Invention I place the wood inside a strong iron
cylinder (such as I now use for creosoting wood, and which is well known),
which is heated inside by steam pipes, and close it up tight; then by large
air pumps, worked by steam engines, I exhaust all the air out of the cylinder
and out of the pores of the wood. After this has been well done I shut off
the exhaust pipe leading to the air pumps, and I open a pipe leading to the
top of large boilers or retorts, hereafter named, in which the materials named
below are placed. The exhausted cylinder is soon filled with the vapours
from the said boilers or retorts, and after that I shut this pipe, and then I
engines, having pipes con-
use large strong force pumps, worked by steam
necting with the tops of these boilers or retorts on one side, and with the said
cylinder on the other. The force pumps draw the vapours out of the boilers
or retorts, and force them into the cylinder and into the pores of the wood
therein. This is to be continued until it has been ascertained by experiment
that the pores of the wood have been well filled with such vapours; after this
is done I open a cock in a pipe leading to a gas-holder, and discharge the
vapours into such gas-holder, and then I sometimes fill the cylinder from an
elevated tank with hot-tar or paint to cover over the pieces of wood externally,
and so close up the pores. In some cases, as where very dry or porous wood
is prepared, and when superheated steam is used, as hereafter described,
it will not be necessary to use the force pumps to force the vapour into
the pores, as such wood will be sufficiently saturated without.
Secondly, I obtain from the materials described in Class 1 and 2, hereafter
named, the vapours which I force into the wood, by placing the liquid materials
named in Class 1 in large boilers having fires under them for heating the
materials and distilling off the vapours, and, in addition to such fires, I some-
times pass superheated steam into the boilers and through the materials in
them, and such steam assists the distillation, and carries off more easily the
volatile products into the cylinder. The vapours from the materials named
in Class 2 are obtained by placing them in retorts, or cylinders, or ovens, such
as are used in gas-making, wood-distilling, and coke-making, and all which,
for the sake of shortness, I shall herein call retorts. These retorts are heated
by fires, and sometimes in addition to such heat I pass superheated steam into
the retorts, which passing through the materials therein, carries off the volatile
products generated into the cylinder.
I will now describe the materials from which I obtain the vapours.

page_text: All kinds of mineral and
tar, tar from bitumens and
or schist.
Class 1.-LIQUIDS.
vegitable tars, including gas tar, coal tar, wood
asphaltes, tar from peat and turf, or from shale
All kinds of hydrocarbon oils, as oil of coal tar, including
napthaline or petroleum, or oil of shale or schist, resinous oils, and all mineral
and hydrocarbon oils.
All kinds of coals, schist, shale, solid pitch, asphalte, or bitumens, or
resin, or peat, or turf, or woods containing oils; or resins, as teak wood, groen
heart wood,.resinous firs, &c. &c., and also woods which on distillation give off
vapours of pyroligneous acid containing kreosote, as birch, beech, or oak.
These materials of Class 2 are placed in retorts, and the vapours distilled
off as above described.
I wish it to be understood that I do not heat the retorts to so great a heat
as is used for making illuminating gas, but I only heat the retorts to such a
heat as will distil off all the bituminous and volatile particles, making a vapour
which will be loaded with the volatile, bituminous, resinous, or acid products,
and I do not condense or purify such vapours as is done in making illuminating
coal gas.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Bethell, in the Great Seal Patent Office on the
22nd June 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
BETHELL, of No. 38, King William Street, in the City of London, Gentleman,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of December, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-ninth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said John Bethell, Her special licence that I, the said John Bethell,
my executors, administrators, and assigns, or such others as I, the said John
Bethell, my executors, administrators, and assigns, should at any time

page_text: agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "]
"IMPROVEMENTS
IN PRESERVING WOOD," upon the condition (amongst others) that I, the said
John Bethell, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said John Bethell, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
My Invention of "Improvements in Preserving Wood" consists in forcing
into the pores of wood the vapours of all the materials named below, in
Class 1 and 2.
In describing these improvements I will first describe the mode by which I
force into the pores of the wood the vapours; and, secondly, I will describe
how I obtain these vapours,. and from what materials.
First, in carrying out this Invention I place the wood inside a strong iron
cylinder (such as I now use for creosoting wood, and which is well known)
which is heated inside by steam pipes, and close it up tight. Then, by large
air pumps, worked by steam-engines, I exhaust all the air out of the cylinder,
and out of the pores of the wood, after this has been well done, I shut off the
exhaust pipe leading to the air pumps, and I open a pipe leading to the top of
large boilers or retorts hereafter named, in which the materials named below
are placed. The exhausted cylinder is soon filled with the vapours from the
said boilers or retorts, and after that, I shut this pipe, and then I use large
strong force pumps, worked by steam engines, having pipes connecting with
the tops of these boilers or retorts on one side, and with the said cylinder on
the other. The force pumps draw the vapours out of the boilers or retorts,
and force them into the cylinder and into the pores of the wood therein.
This is to be continued until it has been ascertained by experiment that the
pores of the wood have been well filled with such vapours. After this is done
I open a cock in a pipe leading to a gas-holder and discharge the vapours
into such gas-holder, and then I sometimes fill the cylinder from an elevated

page_text: tank with hot tar or paint, to cover over the pieces of wood externally, and so
close up the pores. In some cases, as where very dry or porous wood is pre-
pared, and when superheated steam is used, as hereafter described, it will not
be necessary to use the force pumps to force the vapour into the pores, as such
woods will be sufficiently saturated without.
Secondly, I obtain from the materials described in Class 1 and 2, hereafter
named, the vapours which I force into the wood, by placing the liquid
materials named in Class 1, in large boilers having fires under them for
heating the materials and distilling off the vapours, and in addition to such
fires, I sometimes pass superheated steam into the boilers and through the
materials in them, and such steam assists the distillation, and carries off more
easily the volatile products into the cylinder. The vapours from the materials
named in Class 2, are obtained by placing them in retorts, or cylinders, or
ovens, such as are used in gas-making, wood-distilling, and coke-making, and
all which for the sake of shortness I shall herein call retorts. These retorts
are heated by fires, and sometimes in addition to such heat I pass superheated
steam into the retorts, which, passing through the materials therein, carries
off the volatile products generated into the cylinder.
I will now describe the materials from which Lobtain the venouss
All kinds of coals, lignite, schist, shale, solid pitch, asphalte, or bitumens,
or resin, or peat, or turf, or wood containing oils, or resin, as teak wood,
green heart wood, resinous firs, and also woods which on distillation give off
vapours of pyroligneous acid containing creosote, as birch, beech, or oak.
These materials of Class 2 are placed in retorts, and the vapours distilled off
as above described. I wish it to be understood that I do not heat the retorts
to so great a heat as is used for making illuminating gas, but I only heat the
retorts to such a heat as will distil off all the bituminous and volatile particles,

page_text: making a vapour which will be loaded with the volatile bituminous, resinous,
or acid products from the materials used, and I do not condense or purify such
vapours, as is done in making illuminating coal gas.
In witness whereof, I, the said John Bethell, have hereunto set my hand
and seal, this Seventeenth day of June, in the year of our Lord One
thousand eight hundred and sixty five.
Signed, sealed, and delivered
in the presence of
A. H. HOSKING.
JNO. BETHELL. (L.S.)