IMPROVEMENTS IN. PRESERVING WOOD AND IRON
Year: 1861

page_text: LETTERS PATENT to John Cullen, of the North London Railway, Bow,
in the County of Middlesex, for the Invention of "IMPROVEMENTS IN.
PRESERVING WOOD AND IRON."
Sealed the 12th September 1861, and dated the 19th June 1861.
PROVISIONAL SPECIFICATION left by the said John Cullen at the Office
of the Commissioners of Patents, with his Petition, on the 19th June
1861.
I, JOHN CULLEN, of the North London Railway, Bow, in the County of
Middlesex, do hereby declare the nature of the Invention for "IMPROVEMENTS
IN PRESERVING WOOD AND IRON," to be as follows:-
This Invention has for its object improvements in preserving wood and iron.
For these purposes a composition consisting of coal tar, lime, and char-
coal is used. The charcoal is reduced to a fine powder, and such is the
case also in regard to the quicklime. These materials are to be well mixed
and subjected to heat. In order to preserve wood, the composition is heated
and the wood is immersed therein.. The impregnation of the wood with the
composition may be materially aided by means of exhaustion and pressure, as
has heretofore been practised when impregnating wood with other fluids.
Wood thus prepared, in addition to being preserved from decay, will be found
to resist the ravages of the white ant. When coating iron to prevent it from
rust, the composition is heated for a time to a somewhat higher temperature
than is found necessary for wood.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Cullen in the Great Seal Patent Office on the 19th
December 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CULLEN, of the North London Railway, Bow, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Nineteenth day of June, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fourth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Cullen, Her special licence that I, the said John Cullen,
my executors, administrators, and assigns, or such others as I, the said
John Cullen, my executors, administrators, and assigns, should at any
time 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 AND IRON," upon the condition (amongst others) that I,
the said John Cullen, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands.and seals, should particu-
larly 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Cullen, do hereby declare the
nature of the 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 thereof, that is to say :-
This Invention has for its object improvements in preserving wood and iron.
For these purposes a composition consisting of coal tar, quicklime, and
charcoal is used. The charcoal is reduced to a fine powder, and such is the
case also in regard to the quicklime. These materials are to be well mixed
together and subjected to heat. In order to preserve wood, the composition is
heated and the wood is immersed therein. The impregnation of the wood with
the composition may be materially aided by means of exhaustion and pressure,
as has heretofore been practised when impregnating wood with other fluids.
Wood thus prepared, in addition to being preserved from decay, will be found
to resist the ravages of the white ant. When coating iron to preserve it from

page_text: rust, the composition is heated for a time to a somewhat higher temperature
than is found necessary for wood.
And in order that my said Invention may be most fully understood and
readily carried into effect, I will proceed to describe more fully the manner in
which I prefer to conduct the process.
I take coal tar and add to it one-third of its weight of quicklime previously
ground to a fine powder; when these materials have been thoroughly mixed
by stirring, a quantity of finely powdered charcoal, equal in weight to the quick-
lime employed, is also added, and the stirring is continued until the mixing is
complete. In order to preserve timber, the composition above described is
applied to the wood by any of the processes ordinarily employed in preserving
wood when other liquid compositions are employed for the purpose. I prefer,
however, that process in which the pores of the wood are first exhausted of
moisture and sap, and the liquid afterwards forced into the pores. Before em-
ploying the composition for this purpose, I raise it nearly to a boiling tempera-
ture, but I avoid keeping it for any length of time at this heat, so as to
evaporate as little as possible of the more volatile constituents of the coal tar.
When the composition is to be applied to iron, the composition is first boiled
for three or four hours, on purpose to evaporate the more volatilizable consti-
tuents, so that it may afterwards set the harder, and the iron is coated with
the boiling composition, by preference when practicable, by immersing the
ironwork in the composition, or otherwise by applying the composition with a
brush.
In witness whereof, I, the said John Cullen, have hereunto set my hand
and seal, this Tenth day of October, in the year of our Lord One
thousand eight hundred and sixty-one.
JOHN CULLEN. (L.S.)