IMPROVEMENTS IN PRESERVING WOOD
Year: 1874

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lanc,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN PRESERVING WOOD."-A communication from abroad
by Henri Nicolas Rogé, Edouard Porct, Pierre Hypolite Baffoy,
and Pierre Stanislas Eléonore Dupré, all of Paris, France.
Scaled the 25th March 1875, and dated the 3rd October 1874.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 3rd October 1874.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County
of Middlesex, Patent Agent, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN PRESERVING WOOD," to be as
follows:-
This Invention relates to the application of the salts of lead generally,
such as sulphate, azotate, azotites, phosphates, silicates, aluminates,:
chromates, acetates, borates, and carbonate for preserving wood by impreg.:

page_text: nating the same as hereafter described. These salts are employed in com-
bination or mixed with caustic soda or potash, or with an acid, or with a
salt of any kind capable of producing in the pores of the wood an
insoluble or crystallizable precipitate of metallic lead, or a compound.
of lead, such as protoxide or salt of lead, or the salt of lead may be first
injected and then the reagent for producing the precipitate in the pores
of the wood. I may also add to the precipitating substance either a
solution of phenic acid in water, or tar, or other antiseptic matters, or
said antiseptic may be injected afterwards. Wood thus treated will
more perfectly resist moisture than by any other process. The Invention
thus consists in the use in combination of a salt of lead and a reagent
capable of producing an insoluble compound of lead by precipitation in
the pores of the wood.
The injection may be effected by the aid of a vacuum, or by pressure,
or otherwise, and with the aid of heat or not as the case may be.
Coloring matters may be added according to the kind of materials
employed without injuriously affecting the reaction.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 2nd April 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of October, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special licence
that I, the said Alexander Melville Clark, my executors, administrators,
and assigns, or such others as I, the said Alexander Melville Clark,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great

page_text: Britain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN PRESERVING WOOD," a communication to me from
abroad by Henri Nicolas Rogé, Edouard Poret, Pierre Hypolite
Baffoy, and Pierre Stanislas Eléonore Dupré, all of Paris, France, upon
the condition (amongst others) that I, the said Alexander Melville
Clark, 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 Alexander Melville Clark, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement (that is to say) :-
This Invention relates to the application of the salts of lead in general,
such as sulphate, azotate, azotites, phosphates, silicates, aluminates,
chromates, acetates, borates, and carbonate, for preserving wood by
impregnating the same therewith as hereafter described. These salts I
employ combined or mixed with caustic soda or potash, or with an acid
or a salt of any kind capable of producing in the pores of the wood an
insoluble or crystallizable precipitate of metallic lead, or of a compound
of lead, protoxide, or salt of lead, or the salt of lead may be first injected
and then the reagent for producing the precipitate in the pores of the
wood. I reserve the power to add to the reagent by which the pre-
cipitation is obtained either a solution of phenic acid in water, or tar, or
other antiseptic matters, or said antiseptic may be injected into the wood
after the same has been impregnated with said reagent. Wood thus
treated will more perfectly resist moisture than when treated by any
other process.
I reserve the power of effecting the impregnation of the wood either
by the aid of a vacuum, or by pressure, or otherwise, and with the
assistance of heat or not according to the nature of the matters employed.
I also reserve the right of adding coloring matters, which will in no way
prejudice the reaction.
The Invention being based, as before mentioned, on the novel applica-
tion of salts of lead or lead compounds generally for impregnating wood

page_text: also includes the use for this purpose of those lead compounds which are
capable of becoming fixed directly to the wood and of forming insoluble
combinations therewith; as also the employment of plumbic salts
susceptible of spontaneous decomposition in the atmospheric medium
and in the body of the ligneous tissue without the intervention of any
chemical agent. Of such preparations I may mention the plumbates of
lime, soda, and potassa, double hyposulphite of lead and soda, ammonio-
plumbic salts, subacetate or subpyrolignite of lead, and others. The
fixing in the wood of the soluble compounds of lead with which the same
is impregnated may also be effected by the aid of gaseous reagents, such
as ammoniacal and sulphurous emanations or vapors of hydrochloric,
carbonic, or other acids. The pyrolignites of lead and the chlorides and
sulphides of the same base are also intended to be included among the
salts of lead which may be employed for the purposes of this Invention.
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is, the
employment for impregnating wood with the object of preserving the
same of salts or compounds of lead generally, with or without the addition
of tar, phenic acid, or other antiseptics, and suitable coloring matters, all
substantially as specified.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Second day of April,
in the year of our Lord One thousand eight hundred and
seventy-five.