IMPROVEMENTS IN THE PRESERVING AND PREPARING OF WOOD, BRICKS, TILES, AND OTHER SUBSTANCES
Year: 1847

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
Cox, of Number 2, Chapel Place, Battersea Fields, in the Parish of Saint
Mary, Battersea, in the County of Surrey, Electro Caster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent under the Great Seal of the United Kingdom of Great Britain and
Ireland, bearing date at Westminster, the Tenth day of June, in the tenth
year of Her reign, did give and grant unto me, the said Henry Cox, my
exors, admors, and assigns, Her especial licence, full power, sole privilege and
authority, that I, the said Henry Cox, my exors, admors, and assigns, and such
others as I, the said Henry Cox, my exors, admors, or assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term of years therein mentioned, should and lawfully might make,
use, exercise, and vend, within that part of the United Kingdom of Great
Britain and Ireland called England, Her Dominion of Wales, and Town of
Berwick-upon-Tweed, and also in the Islands of Jersey, Guernsey, Alderney,
Sark, and Man, and in all Her Colonies and Plantations abroad, my Invention
of "IMPROVEMENTS IN THE PRESERVING AND PREPARING OF WOOD, BRICKS, TILES,
AND OTHER SUBSTANCES;" in which said Letters Patent there is contained a
proviso requiring that I, the said Henry Cox, shall particularly describe and
ascertain the nature of my said Invention, and in what manner the same is
to be performed, by an instrument in writing under my hand and seal, and

page_text: cause the same to be enrolled in Her said Majesty's High Court of Chancery
within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as, reference being thereunto had, will more
fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Henry Cox, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, are particularly described and
ascertained in and by this present Specification or instrument in writing,
as follows (that is to say):-
My said Invention consists of a mode or modes of preserving or preparing
wood, bricks, tiles, and other substances by depriving them of moisture and by
impregnating them with bituminous substances, either alone or mixed with
other substances, in manner herein-after described; the chief object of my said
Invention being to preserve the substances operated upon from decay or the
attacks of insects, or to make such substances more durable or better adapted
for the purposes to which they are intended to be applied. Any description
of wood may be subjected to my process, but some hard woods will not be so
much benefitted thereby as others. Those kinds of wood which are porous and
which are constantly used for many purposes, such as oak, ash, elm, beach,
birch, fir, and others, may for many purposes be advantageously preserved or
prepared according to my said Invention. The wood which is intended. to be
preserved or prepared according to my Invention must first be deprived of its
moisture, for which purpose I place it in ovens, chambers, or other apparatus
constructed in such manner that the temperature thereof can be regulated
so as to produce any degree of heat which may be required. The heat to which
the wood is thus to be subjected must not reach within fifty degrees of the
temperature which would begin to char the wood, and such temperature
it is well known varies in some degree according to the nature and description
of the wood, but the temperature at which charing commences is generally
about three hundred degrees of Fahrenhiets thermometer.. Unless the wood is
very dry before it is subjected to the drying process, the heat applied in the
first instance must be much lower than the ultimate temperature to which it
is to be exposed; and the heat should in every case be gradually raised to the
highest required temperature, at which the wood should be kept until it is
thoroughly deprived of its moisture, for the purpose of rendering it fit for the
next process or preparation which it has to undergo. And it is to be observed,
that the more damp or wet the wood is when it is first subjected to the drying
process, the lower must be the temperature to which it is in the first instance
exposed. The wood which is intended to be prepared according to my Inven

page_text: tion should not undergo the drying process before described until immediately
before it is impregnated as herein-after described, because by exposure to the
atmosphere it would very soon imbibe such a quantity of moisture as would
prevent it from being properly impregnated. The wood thus prepared is now
ready to be impregnated with the melted bituminous substance or substances
with which it is intended to be impregnated. The bituminous substances
which I employ for this purpose are the residuum remaining after the
distillation of gas tar, or pitch, asphalte, or any other bituminous substance
which can be liquified by heat, but which remains solid at all ordinary tem-
peratures of the atmosphere. The bituminous substances to be used must
however be such as will be liquified and remain liquid at a temperature lower
than that at which wood would be charred. The bituminous substances used
for impregnating or preparing wood according to my Invention may be mixed
with some other substance or substances which may be necessary for causing
the wood to possess certain qualities after it has been impregnated or prepared,
but the substance or substances so mixed with a bituminous substance must
be such as will thoroughly mix or combine with it, and I deem it preferable
that the mixture should be such as will remain solid at all ordinary temperatures
of the atmosphere. If it is intended to impregnate any of the common soft
woods such as fir, poplar, willow, lime, beech, ash, or elin, so as to render
them better fitted to be used in the manufacture of furniture or for ornamental
purposes, I prefer to prepare the substance for impregnating them as
follows: I boil the residuum of gas tar (which remains after naptha has
been distilled from it, and which is sometimes called English pitch,) or other
bituminous substance, which I use in a solution of potash, lime, or other alkali
or alkaline earth for the purpose of neutralizing the acids and taking up the
oils with which bituminous substances are generally mixed. If I employ
caustic potash or soda, a weak solution will be sufficient, but if lime be
used, the solution should be saturated or nearly so. A solution of one
ounce of alkali to a gallon of water will be found of a useful strength,
but the quantity of alkali or earth used in the solution must depend
upon the quantity of acid mixed with the bituminous substance, and the
quantity of alkali or earth should be sufficient to neutralize the whole of the
acid. The boiling should be continued about two or three hours, during
which the melted bitumen and solution should be frequently agitated so as to
secure the action of the solution upon every part of the mass of bituminous
substance, after which the solution is to be poured off or suffered to run out
of the vessel in which it has been boiled; and if it be desired to have the
bituminous substance very purc, it should be washed with hot water so as the

page_text: more effectually to free it from any admixture with the solution or with any
substance which it may have taken up during the process of boiling. This
bituminous substance is then to be heated until the whole of the moisture
remaining in contact with it has been driven off. To the bituminous
substance thus prepared and in the melted state, I had one per cent. of
stearine, and mix them until they are thoroughly incorporated, and impregnate
the wood to be operated upon in manner before mentioned and herein-after
described. If it be desired that the wood shall be made of a lighter colour
than it will possess if the bituminous substance be mixed with only one per
cent. of stearine, I increase the proportion of stearine to the extent which may
be requisite for producing the desired effect. I also in some cases make
wood of. a lighter colour by saturating it partially with the bituminous
substance instead of causing it to be completely saturated. I prefer to mix
the bituminous substance with stearine in this way rather than with tallow
or any other description of fatty matter, because stearine is harder or firmer
and not so likely to undergo putrifaction or decomposition, and I would mix
the bituminous substance with stearine in every case in which the price of
that substance would not preclude the employment of it; this mixture of a
bituminous substance with stearine, I deem to be of great value for impreg-
nating wood and other substances in the manner described in this Specification,
and the proportion of stearine might in many cases be increased to one-half
with advantage were it not for the great expense of that article. Bituminous
substances may in this way be mixed with resins, gums, gum resins, sper-
maceti, and other similar substances for the purposes of my Invention; thus,
if it be desired that the prepared wood shall be made harder by the substance
with which it is impregnated, I mix the bituminous substance with shell-lac,
seed-lac, gum, sandrac, mastic, copal, resin, or any such substance as aforesaid,
which will produce or have a tendency to produce that effect. If. it be
desired that the wood should possess greater elasticity, I mix the bituminous
substance which I use for impregnating it with caoutchouc, gutta percha,
jintawan or mineral caoutchouc, or with any of those substances in solution.
And when necessary for the purpose of producing the required effect upon
the wood to be operated upon, I mix the bituminous substance with two or
more of such other substances as aforesaid which may possess qualities fit for the
purpose. When it is desirable to preserve the prepared wood from the ravages
of insects, I mix the bituminous substance with which it is to be impregnated
with some poisonous substance, such as orpiment, oxide of arsenic, or some
of the compounds of arsenic, mercury, or lead, preferring those substances
which are most poisonous and least expensive; for this purpose I first molt

page_text: the bituminous substance in some convenient vessel, and then add to it the
poisonous substance or substances with which I may intend it to be mixed, the
poisonous substance or substances being first reduced to a fine powder. For
the purpose of insuring the effectual incorporation of such powdered poison
with the melted bituminous substance, I add the powder gradually through a
fine sieve, and whilst I am so doing I keep the melted substance in continua!
agitation, the agitation being afterwards continued until the materials have
been thoroughly incorporated. The quantity of such poisonous substance as
aforesaid which I add to any melted bituminous substance is about twenty
pounds weight to a ton of the melted bituminous substance; the quantity may,
however, be varied according to the nature of the poison used. Thus, if the
bichloride of mercury be used, the quantity of it mixed with a ton of melted
bitumen need not be quite so much as twenty pounds weight. The wood
being prepared as before mentioned is to be impregnated with a bituminous
substance such as herein-before mentioned, either mixed or unmixed with any
other substance or substances, as herein-before mentioned. This impregnation
may be effected either by simply immersing dried wood in the bituminous
substance when liquified by heat, or by immersing the dried wood and also
exausting the air from the vessel containing the wood and the melted bitu-
minous substances. If the wood is to be impregnated by immersion only, I
melt the bituminous substance (either mixed with any other substance or
substances or not) in a cauldron or other convenient vessel, and I then im-
merse the wood in a heated state in the melted substance, and keep it so
immersed until the wood has been sufficiently impregnated. During the
whole of the operation the melted substance must be kept at a temperature
sufficiently high to make it perfectly liquid, which of course will vary accord-
ing to the nature and quality of the bituminous substance used. Care must,
however, be taken not to raise the temperature of the melted bitumen to such
a degree as to char the wood when immersed in.it. The wood may either be
placed in a horizontal or vertical position in the melted substance, as may be
deemed most advantageous for facilitating the process, but I am not aware of
any advantage which either of those positions possesses over the other for the
purpose I have mentioned. The time during which wood must be immersed
in the melted substance in order to be sufficiently impregnated will vary from
four to twenty-four hours, according to the nature of the bituminous substance
which may be used, and the quality and dimensions of the timber to be impreg-
nated. I believe that wood will be sufficiently impregnated with a bituminous
substance such as I have mentioned by merely keeping it immersed in the
melted substance for a sufficient length of time in manner herein-before

page_text: described; but the impregnation of wood may be more quickly and perhaps
more perfectly effected by exhausting the air from the vessel in which the
wood is to be impregnated, or by subjecting the contents of the vessel to a
considerable compression by means of a force-pump, or by the employment of
both of those means. For the purpose of enabling the operator to employ ex-
haustion and compression, or either of those means at pleasure for facilitating the
impression of wood, it will be better to obtain a vessel of any suitable and con-
venient size and shape, which can be made air-tight and be exhausted of air, and
which is sufficiently strong to bear the amount of pressure which may be used;
and the vessel must be so constructed or placed that the bituminous substance
to be put into it may be melted therein, or at all events kept melted during
the process of impregnating the timber to be placed in it for that purpose.
Such a vessel as I have described having been obtained, the requisite quantity
of the bituminous substance intended to be used, whether mixed with any
other substance or not, is to be put into it and melted, as herein-before
described, taking care that sufficient space is left for the introduction of the
wood intended to be operated upon. The wood having been dried and heated,
as before described, is then to be plunged into the melted bituminous substance
in the vessel, and the vessel closed and made air-tight. If exhaustion be
intended to be used the air must be exhausted from the vessel by means of an
air-pump or air-pumps of sufficient power, as much as conveniently may be,
and after the vessel has been kept so exhausted for a short time the air may
be permitted again to have access to the vessel.
This operation may
bo
repeated if thought desirable, the bituminous substance being kept perfectly
melted during the whole of the process. By the exhaustion of the air from
the vessel the air contained amongst the fibres of the wood in the vessel will
also be exhausted or drawn out of it, and the impregnation of the wood by the
bituminous substance will be much facilitated. If compression be intended
to be employed, air must be forced into the vessel by means of one or more
force pumps of sufficient power to produce the amount of compression which
may be intended, and the amount of compression which is given may be varied
at pleasure and as may be deemed expedient. The compression should be
kept up for a convenient time according to the size and quality of the piece or
pieces of wood operated upon, so as to force the melted bituminous substance
more effectually into or amongst the fibres of the wood. Pieces of wood after
being impregnated with any bituminous substance as herein-before described
are to be taken out of the melted substance and placed in such a position that
the superfluous parts of the substances adhering to them may run off into
some convenient vessel in which it may be received and preserved for use,

page_text: and, if necessary, such superfluous parts of the substance must be scraped off,
or otherwise detached from the wood. The wood when thus prepared is to be
set aside to cool, after which it is ready for being used or applied in the
manner intended.
Some porous substances, such as bricks, tiles, or unglazed pottery ware,
which are or can be made quite dry, may also be subjected to my process, and
impregnated with any of the bituminous substances before mentioned, in
manner herein-before described with respect to the impregnation of wood.
Such porous substances must first be thoroughly dried, so that all the aqueous
particles (which would prevent the impregnation of them by the bituminous
substances) may be driven out of them; and they must also be introduced
into the melted substance in a heated state. For the purpose of impregnating
bricks, tiles, and such porous substances as aforesaid, I employ bituminous
substances of the same description as I use for impregnating wood, and either
mixed or not with such other substances as aforesaid. The time required for
saturating a brick or tile by immersion merely will vary from one hour to two
hours. When a bituminous substance is intended to be used for impregnating
some hard substances such as bricks and tiles, which are not liable to be
destroyed or injured by insects, it will not be necessary to mix the bituminous
matter with any poisonous substances, as herein-before described. And if any
substance to be operated upon according to my Invention is intended to be
used for such a purpose as will cause it to come in contact with food of any.
description, the use of poisonous matters would be improper. When any
such substances so intended to be operated upon are hard or inflexible, the
admixture of any india rubber, gum, or other substance with the bituminous
substance for the purpose of making it elastic will be unnecessary.
Bricks and tiles of very inferior qualities may be advantageously prepared
according to my Invention, and the substances with which they may be thus
impregnated will have the effect of rendering them impervious, or nearly so,
and of greatly preserving them from being injured by frost, and from injury
by many other causes. And even unburnt bricks and tiles may be impreg-
nated according to my Invention, if they be first made quite dry, and when so
impregnated will be durable. When bricks or tiles prepared by means of
my Invention are used, the mortar usually employed for building purposes
cannot be used beneficially for cementing them, but in lieu thereof a
bituminous cement should be used. A bituminous cement for this purpose
may be made by mixing (when hot) a quantity of the residuum, which remains
after the distillation of gas tar or other tars with such a quantity of dry sand
or chalk as will make the cement in the heated state have the consistence of

page_text: treacle; this cement must of course be used in a hot state. Pieces of dried
peat or turf may be prepared and impregnated according to my Invention in
like manner, as herein-before described with respect to the preparation of bricks
and tiles, and pieces of peat or turf thus prepared may be used for many
purposes similar to those for which bricks are used.
Having now described the nature of my Invention, and the manner in which
it is to be performed, 1 hereby declare that I claim as of my Invention,
firstly, the mode of preserving and preparing wood, bricks, tiles, and other
substances, by depriving them of moisture and impregnating them with
bituminous substances, either mixed or unmixed with other substances, as
herein-before described; and, secondly, the mixture of any such bituminous
substance as aforesaid with stearine for the purpose of impregnating wood and
other substances in manner herein-before described.
In witness whereof, I, the said Henry Cox, have hereunto set my hand
and seal, this Twentieth day of November, in the year of our Lord
One thousand eight hundred and forty-seven.
HENRY (L.S.) COX.
AND BE IT REMEMBERED, that on the Twentieth day of November,
in the year of our Lord 1847, the aforesaid Henry Cox came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according to
the tenor of the Statute made for that purpose.
Enrolled the Ninth day of December, in the year of our Lord One
thousand eight hundred and forty-seven.