IMPROVEMENTS IN THE MANUFACTURE OF A COMPOUND TO BE USED AS A VARNISH FOR WATER COLOURS, AND ARA CARRIER FOR WATER COLOURS OR PAINTS
Year: 1856

page_text: LETTERS PATENT to William Renwick Bowditch, Clerk, of Wakefield,
in the County of York, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF A COMPOUND TO BE USED AS A VARNISH FOR WATER COLOURS,
AND ARA CARRIER FOR WATER COLOURS OR PAINTS"
Sealed the Sth May 1857, and dated the 29th December 1856.
PROVISIONAL SPECIFICATION left by the said William Renwick Bowditch
at the Office of the Commissioners of Patents, with his Petition, on the
29th December 1856.
I, WILLIAM RENWICK BOWDITCH, Clerk, of Wakefield, in the County of
York, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF A COMPOUND TO BE USED AS A VARNISH FOR WATER
COLORS, AND AS A CARRIER FOR WATER COLOURS OR PAINTS," to be as follows:-
1 employ milk, or the casein thereof, and ordinary soap, decomposed by
certain alums or by sulphuric acid, and incorporate them by stirring and
grinding in an ordinary color mill. The quantity of alum or of acid used is
as much as will decompose the milk and soap and no more. To this compound
I add creasote or carbolic acid, till their odour is just perceptible, after being
thoroughly mixed with the compound. If necessary water is added to facilitate
the grinding of this compound; or, I employ casein dissolved in a solution of
borax, or ofanalkalinecarbonate, and grind this with the abovedecomposedsoap
and sufficient waterto make it pass properly through the colour mill,and when
the compoundis made I add creasoteor corbolic acid. Or, I grind thesolution
Price 8.1

page_text: of casein with a soap of lime, or baryta, or lead in so much water as will
render the mass fit to be ground fine in an ordinary colour mill, and add
creasote or carbolic acid, as above. No more of the solution of borax or of
the alkaline carbonate is employed than is necessary to dissolve the casein.
I add water if necessary to one or other of the above compounds till it is of
the thickness of a very thin paint, and then apply it as a varnish to ordinary
paper hangings to make them washable, or to water colours upon wood or
walls. And I also employ one or other of the above compounds as a vehicle
or carrier for water colors, which I prepare for use by grinding the colours
with such vehicle in a colour mill in the ordinary manner.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Renwick Bowditch in the Great Seal Patent Office
on the 19th June 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM)
RENWICK BOWDITCH, Clerk, of Wakefield, in the County of York, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of December, in the year of our
Lord One thousand eight hundred and fifty-six, in the twentieth year of Her
reign, did, for Herself, Her heirs and successors, give aud grant unto me,
the said William Renwick Bowditch, Her special licence that I, the said
William Renwick Bowditch, my executors, administrators, and assigns, or
such others as I, the said William Renwick Bowditch, my executors, adminis-
trators, 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 THE MANUFACTURE OF A COMPOUND
TO BE USED AS A VARNISH FOR WATER COLOURS. AND AS A CARRIER FOR WATER
COLOURS OR PAINTS," upon the condition (amongst others) that I, the said
William Renwick Bowditch, my executors or administrators, by an instru-
ment in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Inven-
tion, 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.

page_text: NOW KNOW YE, that I, the said William Renwick Bowditch, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement:-
I take of milk one gallon, of hard soap two pounds, and common alum one
and a half pound. The soap is sliced thin and put into the milk, which is
heated to about one hundred and twenty degrees (Fahrenheit), and the mixture
is stirred until the soap is dissolved in the milk. The alun is dissolved in the
smallest possible quantity of water, and is then added to the mixture of soap
and milk, and thoroughly incorporated by stirring. When the whole is per-
fectly mixed the mass is ground fine in an ordinary colour mill. If it be
found too thick to grind easily it may be diluted with water, and if too thin
part of the fluid may be filtered off by a linen or cotton filter. When ground,
the semi-fluid mass is to be washed with water until the wash water hardly
reddens blue litmus paper. The washing may be effected by putting the whole
mass into a tub or other suitable vessel, and adding about three times its
volume of water, and mixing all together thoroughly. It is then to be left at
rest until the water at the top is clear, and this clear fluid is to be run off by a
syphon, a tap, or other convenient means. More water is then to be added, as
at the first, the whole mixed, left to settle, and the clear fluid drawn off. This
is to be repeated until the clear water on the top of the thick white mass
hardly affects blue litmus paper. A better mode of washing is to throw the
ground mass upon a linen or cotton filter, and pour water through it until
nearly all the salts are removed. This will be when the wash water which has
passed through the mass in the filter no louger has much effect upon blue
itmus paper. All acid can be removed by washing, but the process is tedious,
and I dc not find the advantages compensate the trouble. The washed mass
must on no account be suffered to remain on the filter, or out of water exposed
to the air, but directly the washing is completed must be removed to a suitable
store vessel, and be covered with as much water as will stand an inch or two
above it. Indeed, it must always be kept under water, and if at any time too
much is added it may be poured off after subsidence of the varnish. The
water which is addede to the mass after washing should have a little creasote,
carbolic acid, or corrosive sublimate added to it to prevent decomposition.
Twenty grains of the latter, or fifty drops of either of the two former sub-
stances will be sufficient. The milk I prefer to be skimmed, and the soap to
be "white curd," but good pale yellow soap may be employed instead.
Common potash alum or ammonia alum may be employed, or an equivalent
quantity of sulphuric or hydrochloric acid, but the best substance for use is

page_text: tersulphate of alumina, known I believe in commerce as "concentrated alum."
The quantity employed should contain the same amount of sulphuric acid as
the above-mentioned quantity of common alum. For use, the prepared mass
is to be diluted with water to about the thickness of ordinary paint, and to be
applied by means of a brush to paper hangings like ordinary varnish. When
dry, the paper will bear washing with flannel and soap and water, and no
offensive smell attends the use of the varnish. For painting, it is mixed with
colours ground in water, and applied in the usual manner.
Having described the nature of my Invention, and the mode in which it is
to be performed, I claim the improvements in the manufacture of the said
varnish, by the washing of the varnish when made with water in the manner
above described, by which soluble salts are removed from it.
And I claim also the improvements in the said manufacture by the appli-
cation of the several materials above specified, to prevent or lessen the tendency
to putrefaction of the varnish when made.
In witness whereof, I, the said William Renwick Bowditch, have here-
unto set my hand and seal, this Seventeenth day of June, in the year
of our Lord One thousand eight hundred and fifty-seven.
W. R. BOWDITCH. (L.S.)