AN IMPROVEMENT IN PREPARING MARKING COMPOUNDS TO BE USED ON LINEN AND OTHER FABRICS
Year: 1858

page_text: LETTERS PATENT to Arthur Dunn, of 1, Dalston Terrace East, in tho
County of Middlesex, Fancy Soap Maker, for the Invention of "AN
IMPROVEMENT IN PREPARING MARKING COMPOUNDS TO BE USED ON LINEN AND
OTHER FABRICS."
Scaled the 12th April 1859, and dated the 16th October 1858.
PROVISIONAL SPECIFICATION left by the said Arthur Dunn at the
Office of the Commissioners of Patents, with his Petition, on the 16th
October 1858.
I, ARTHUR DUNN, of 1, Dalston Terrace East, in the County of Middlesex,
Fancy Soap Maker, do hereby declare the nature of the Invention for "AN
IMPROVEMENT IN PREPARING MARKING COMPOUNDS TO BE USED ON LINEN AND OTHER
FABRICS," to be as follows:-
This Invention has for its object an improvement in preparing marking
compounds to be used on linen and other fabrics. Heretofore, marking
materials, when for writing or marking on linen and other fabrics, have been
made up in the form of fluid inks, suitable for being used with an ordinary
pen. Now, my Invention consists in making up materials, such as tho
compounds of silver or other metals heretofore used in the preparation of
marking inks, in a solid state, in combination with any suitable material, but I
prefer to use a material such as black lead or other dark substance capable of

page_text: giving colour when first used, and before the light or heat, if applied, has had
time to act; and such dry compounds, in carrying out my Invention, are
made up in suitable forms to be used in ever-pointed pencils, or in other
suitable holders. In using such marking instruments I prefer that the linen
or other fabrics should be first damped, and then written on whilst damp.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Arthur Dunn in the Great Seal Patent Office on the
16th April 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ARTHUR
DUNN, of 1, Dalston Terrace East, in the County of Middlesex, Fancy Soap
Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of October, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Arthur Dunn, Her special licence that I, the said Arthur Dunn, my
executors, administrators, and assigns, or such others as I, the said Arthur
Dunn, 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 "AN IMPROVEMENT
IN PREPARING MARKING COMPOUNDS TO BE USED ON LINEN AND OTHER FABRICS,"
upon the condition (amongst others) that I, the said Arthur Dunn, 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 Arthur Dunn, 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
thereof, that is to say :-
This Invention has for its object an improvement in preparing marking
compounds to be used on linen and other fabrics. Heretofore, marking

page_text: powdered base before described, I then heat the mortar or other apparatus,
and rub or grind with the pestle until the nitrate of silver and the base form
a pasty mass, and I continue such rubbing or grinding until the whole is
thoroughly incorporated; and I find it desirable in this process to keep the
temperature of the mortar or other apparatus at about 180° Fahrenheit
during the operation of mixing.
I would here remark that it is most important to incorporate the ingredients
until they rub perfectly smooth in the mortar. When the mixing is complete
I turn off the heat, and allow the mixture to cool down gradually to about
60° to 70° Fahrenheit, rubbing with the pestle the whole time; by which
means I reduce the dry compound or ink to powder. I then sift it through
a moderately fine muslin sieve, returning to the mortar and again gently
rubbing that portion which does not pass through the sieve, and so on, until
the whole is sifted.
I would here remark that the mixture powders most readily if the mortar
is kept moderately warm, say, about 60° to 70° Fahrenheit. The rubbing
towards the last should be light, otherwise the mixture is liable to clog
together, making it difficult to sift.
I next proceed to make the powdered ink or marking compound into
blocks suitable for being cut into points or other suitable forms, in like
manner to that in which black lead has heretofore been cut for use as pencils.
I weigh out portions of the dry ink powder according to the size of the
block required upon clean pieces of paper, and I place these in an oven
capable of being beated by any suitable means (I prefer gas) to a temperature
of about 120° to 130° Fahrenheit. The pieces of paper holding the ink
powder should be placed in the oven upon a wood shelf or other imperfect
conductor of heat. I apply the heat gradually until the whole is heated to
about 120° to 130°; care must be taken not to melt the powdered ink, the
object of applying heat being simply to make the mixture clammy. When
heated, I place the mixture in a suitable mould of the required size, made of
gun metal or cast iron. The mould I employ is of gun metal body with an
irou plug, the part to hold the ink powder being 2 x 21 inches, with about
1 inch solid metal all round, and 6 inches deep, resting upon the centre of a
cast-iron plate 15 x 15 inches and 2 inches thick, and fitted with suitable
levers to hold down the body of the mould. The plate is fixed upon a solid
wood block of suitable height. I prefer slightly to warm the mould by any
convenient means to a temperature of 70° or 80° Fahrenheit. Before intro-
ducing the heated ink powder into the mould, I rub the internal parts of the
mould over with plumbago; I then quickly pour the powdered dry ink, when

page_text: taken from the heated oven, into the mould, and immediately introduce the
solid iron plug, and strike the same with a heavy mallet 10 or 12 or more
times, or pressure or impact may be applied by means of a fly press or tilt
hammer, or otherwise. I have found the action of a heavy mallet answer
well, the object being, however it is done, to subject the dry powder to great
mechanical pressure, so as to obtain it in a solid form. The mould is then
lifted off the plate, and by gently striking the plug the moulded mass is easily
pushed through and delivered from the mould; should the powder or mould
by any chance have been worked too hot, it should be left to rest in the mould
a few minutes to cool before attempting to remove it. These blocks, when
cold, may then be cut into slabs of the required thickness in the usual way
with a saw, as used for cutting ordinary black lead, or a circular saw may be
used, preferring one with a straight tooth, or as it is termed without a set. It
is desirable that the blocks of moulded dry ink should not be cut until they
have been made some time, and that they should be kept in a cool, dry, and
dark place. If the cut pieces are to be used in ever-pointed pencil cases, the
strips of marking ink are to be prepared in like manner to that practised when
black lead is used, as is well understood.
When using such prepared inks in ever-pointed pencils, when nitrate of
silver or other substances capable of acting prejudicially on metals is used, it is
preferred to employ ever-pointed pencil cases made of wood or ivory, or other
material not prejudicially acted on by the preparation of ink; and when using
a metal propeller in such ever-pointed pencils, I prefer to apply enamel to the
ends which come in contact with the marking ink, or otherwise to provide, in
order to prevent the marking ink coming in contact with metal. Or, the cut
marking ink may be introduced into wood as heretofore has been the practice
when making black lead pencils, in which case the points would be formed by
cutting the ends. Tartrate, acetate, carbonate, and other salts and compounds
of silver will give a permanent mark when moulded into the solid form, but I
believe the nitrate of silver to be the best material; the fabric or material
being damped either with water, but what is preferred is water having in
solution the neutral tartrate of potash, in the proportion of 1 oz. of the tartrate
to 3 ozs. of water, and after writing thereon, a moderately heated iron should be
immediately applied to the fabric at the written parts, but at the reverse side,
when the writing will become black, or the parts of the fabric written on may
be exposed to fire heat or to the sunlight. Small quantities of perchloride of
gold, or etherial solution of gold, mixed in with the nitrato or other salts of
silver renders the marking more permanent against the action of chlorine.
The nitrate and other silver salts when prepared into the form of pencils make

page_text: permanent marks, even if used dry, when exposed to light or heat; with
water alone they make a very good mark, either with light or heat, on damp
fabrics or wood, or ivory, or other surface, but in all cases it is preferred to
damp the surface.
I would state that the proportions above given may be varied, or other
materials used, without departing from my Invention; but I believe the pro-
portions and materials above described the best for the purpose. Other
coloring material besides plumbago may be used in preparing the base, thus
vermillion with a little carmine does well. Various other modes may be used
for obtaining the marking ink in a solid form.
The points for refilling ever-pointed pencil cases may be packed in glass
tubes and boxes as ordinary lead points.
In witness whereof, I, the said Arthur Dunn, have hereunto set my hand
and seal, this Fifteenth day of April, in the year of our Lord One
thousand eight hundred and fifty-nine.
Witness,
S. CARPMAEL.
ARTHUR DUNN. (L.S.)