IMPROVEMENTS IN THE MANUFACTURE OF PAPER FROM WHICH WRITING OR OTHER INKS CANNOT BE EXPUNGED OR EXTRACTED WITHOUT DEIECTION
Year: 1859

page_text: LETTERS PATENT to Robert Barclay, of Bucklersbury, in the City of
London, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
PAPER FROM WHICH WRITING OR OTHER INKS CANNOT BE EXPUNGED OR
EXTRACTED WITHOUT DEIECTION."
Sealed the 4th November 1859, and dated the 7th June 1859.
PROVISIONAL
SPECIFICATION left by the said Robert Barclay at the
Office of tic Commissioners of Patents, with his Petition, on the 7th
June 1859.
I, ROBERT BARCLAY, of Bucklersbury, in the City of London, do hereby
déclare the nature of the Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF PAPER FROM WHICH WRITING OR OTHER INKS CANNOT BE EXPUNGED OR EXTRACTED
WITHOUT DETECTION," to be as follows:-
Method No. 1.-I incorporate in the substance of the paper during the
process of manufacture the soluble and insoluble ferro-cyanides, ferrid-cyanides,
and sulpho-cyanides of tin, bismuth, zinc, copper, lead, nickel, chromium,
antimony, aluminium tungsten, barium, strontium, magnesium, and calcium,
either as salts with single bases, or as salts with more than a single base, or as
salts having in addition to one or more bases, potassium, sodium, or ammo-
nium, as additional bases. I call the ferro-cyanide of copper a salt with a
single base, and I call the ferro-cyanide of magnesium and potassium a salt,
having in addition to one base (viz. magnesium) potassium as an additional
base. In conjunction with any of the above named substances I incorporate
in addition to them during the process of manufacture any vegetable or animal
colouring matter, or metallic colour, or any insoluble or soluble salt of
manganese, nickel, or lead, which is not deliquescent, and does not contain
027

page_text: ferro-cyanogen, and which is turned a diverse tint, or whose color is destroyed
by alkalies, alkaline salts, chlorine, or bromine, or their compounds.
Method No. 2.-I incorporate in the substance of the paper during the
process of manufacture ary soluble salt (which is not deliquescent), or any
insoluble (not containing ferro-cyanogen) of manganese, lead, or nickel, in
conjunction with any animal or vegetable colouring matter or metallic colour
whose tint is changed or destroyed by acids or acidulous salts or alkalies or
alkaline salts.
Method No. 3. I incorporate in the substance of the paper during the pro-
cess of manufacture, the ferro-cyanides, ferrid-cyanides, and sulpho-cyanides
of potassium, sodium, and ammonium, in conjunction with any insoluble salt
of manganese, lead, or nickel, or any animal or vegetable coloring matter, or
metallic colour whose tint is destroyed or turned a diverse colour by alkalies,
alkaline salts, chlorine, bromine, or their compounds.
Method No. 4.-I incorporate in the substance of the paper, during the pro-
cess of manufacture, the insoluble ferro or ferrid cyanide of manganese, or
the soluble sulpho-cyanide of manganese, either as single salts or combined
with potassium, sodium, or ammonium, as salts, with double bases, for example
the ferro-cyanide of manganese and potassium is such a salt with a double base.
I would remark that I am aware that it has before been proposed to prepare
paper by incorporating with it a precipitate obtained by the addition of ferro-
cyanide of potassium to a mixture of chloride of manganese and chloride of
calcium; but I have found that this precipitate, when exposed to the air,
becomes discoloured; and it is therefore unsuited for the use to which it was
proposed to apply it. This discoloration arises from the presence of the
calcium salt, when the ferro-cyanide of potassium was added.
I do not,
therefore, claim the preparation of paper with the precipitate obtained by the
addition of ferro-cyanide of potassium to a solution containing both manganese
and calcium, as above-mentioned.
The substances above-mentioned, which are insoluble, I incorporate in the
paper pulp in the beating engine of the paper maker, while those which are
soluble I dissolve in the size in the process of sizing. And as most of the
substances specified, when incorporated in the paper, are changed and altered
in color, when sized by the method usually adopted by paper makers of
dissolving potash alum in the animal and vegetable size used. And as this
change of color is a great obstruction to its use, for many purposes to which
the papers are applicable, and renders the stain produced by ink-discharging
chemicals, when applied to the papers, less evident in sizing papers pre-
pared by either of the methods above described; to avoid this change as much

page_text: as possible, I size the paper in a continuous sheet, and then dry it by means
of sizing and drying machines, such as are now frequently used by paper
makers, and in which the paper is caused to pass in a continuous sheet through
or in contact with the size, and afterward over open-work or skeleton rollers
in a drying chamber. By this means the size becomes dried in so short a time
after its application, that the chemical action is stopped before it can proceed
to a very injurious extent. In some cases, to render the size less liable to
produce discoloration, I use the acetate of alumina, or the sulphate or sub-
sulphate of alumina, either entirely in lieu of alum, or mixed with a small
proportion of potass or ammonia alum, or I use any other preparations of
alumina, which are less acid than common alum. I have found also that the
addition of a proto-salt of tin either to the paper or to the size, has a tendency
to reduce the amount of discoloration which the size produces.
same object in view, of preventing the extraction, of inks from paper, I apply
printers' inks, and other materials attached to the surface of paper. In this
case I use the substances mentioned in the four specified methods of making
the indelible papers. When only one substance is incorporated in the paper,
as in Method No. 4, I grind and thoroughly mix it with the printers' ink or
surfacing material; but where, as in Methods 1, 2, and 3, two substances are
needful to produce the required effect, they may be ground either in a state of
mixture with the printers' ink or surfacing material, or one substance only
may be incorporated in the paper, and the other may constitute or be incor-
porated in the ink printed thereupon, or vice versa.
With the
The Method No. 3 may be varied thus: A paper is prepared with ferro-
cyanide of potassium and a printers' ink containing a vegetable coloring
matter or mineral color, or an insoluble salt of manganese, lead, or nickel. may
be printed on the surface which is affected by alkalies, alkaline salts, chlorine,
bromine or thir compounds.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Barclay in the Great Seal Patent Office on the
6th December 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I. ROBERT
BARCLAY, of Bucklersbury, in the City of London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by. Her Letters
Patent. bearing date the Seventh day of June. in the year of our Lord
One thousand, eight hundred and fifty-nine. in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,

page_text: the said Robert Barclay, Her special licence that I, the said Robert Barclay,
my executors, administrators, and assigns, or such others as I, the said Robert
Barclay, 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 THE MANU
FACTURE OF PAPER, FROM WHICH WRITING OR OTHER INKS CANNOT BE EXPUNGED
OR EXTRACTED WITHOUT DETECTION," upon the condition (amongst others) that I,
the said Robert Barclay, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly 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 Robert Barclay, 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 follow-
ing statement thereof; that is to say :-
Method No. 1.-I incorporate in the substance of the paper, during the
process of manufacture, the soluble and insoluble ferro-cyanides, ferrid-
cyanides, and sulpho-cyanides of tin, bismuth, zinc, copper, lead, nickel,
chromium, antimony, aluminium, tungsten, barium, strontium, magnesium,
and calcium, either as salts with single bases, or as salts with more than a
single base, or as salts having, in addition to one or more bases, potassium,
sodium, or ammonium as additional bases. I call the ferro-cyanide of
magnesium and potassium a salt, having in addition to one base (viz.
magnesium) potassium as an additional base.
In conjunction with any of the above-named substances, I incorporate, in
addition to them during the process of manufacture, any vegetable or animal
coloring matter or metallic colour, or any insoluble or soluble salt of man-
ganese, nickel, or lead, which is not deliquescent, and does not contain ferro-
cyanogen, and which is turned a diverse, or whose color is destroyed by
alkalies, alkaline salts, chlorine or bromine, or their compounds.
In carrying out this part of my Invention, I proceed in the following
manner In the paper maker's engine, containing a quantity of pulp pro-
duced from 140 lbs. of rag. I mix 2 quarts of engine size, prepared from a
caustic alkali and resin in the usual way, of a strength which may be
described by stating it should be of the consistency of the thickest treacle, first

page_text: dissolving it in a pailfull of boiling water; then I also add from 1 to 2 lbs. of
starch dissolved in boiling water. After these are thoroughly beaten with the
pulp, I add 7 lbs. of alum, or a quantity of acetate of alumina prepared from
7 lbs. of alum. After running this mixture into the stiring chest, I add 12 lbs.
of one of the insoluble ferro-cyanides, ferrid-cyanides, and sulpho-cyanides
above mentioned. I, however, much prefer to emply the ferro-cyanide of lead
in the state of an impalpable powder, together with 8 lbs. of an insoluble salt
of manganese, nickel, or lead not containing ferro-cyanogen. I prefer to
employ sulphite or phosphate of manganese, and the whole is violently agitated
and stirred in the chest; and without allowing it to stand, I commence.
without delay, to turn it on to the machine, and convert it into waterleaf or
partially-sized paper. This quantity of engine size and starch and alum is
considerably greater than is used in the manufacture of ordinary white writing
paper; my object in this is to prevent the great waste of the lead and man-
ganese salts through the wires of the machine.
The use of a considerable quantity of alum is here unobjectionable, provided
it is not allowed to remain for many hours in contact with the ferro-cyanide:
the engine size tends to neutralize its acid quality; the starch also tends to
impede the chemical action, and it is in this case protected from the absorbtion
of oxygen from the atmosphere while in contact with the alum. I prefer even
in this case, however, the use of the acetate of alumina. In applying animal
size to paper manufactured as above described, as the ferro-cyanide of lead. and
most of the substances specified when incorporated in the paper are changed
and altered in color when sized with size such as is usually employed by paper-
makers, and which contains potash alum; paper mannfactured as above
described cannot practically be sized by the hand process, if size containing
the ordinary proportion of alum be used, as paper sized by the hand process is
allowed to remain moist for a considerable time, and the alum in the size then
produces such a change of color as is a great obstruction to the use of the
papers for many purposes to which they are applicable, and renders the stain
produced by ink-discharging chemicals when applied to the papers less evident.
In sizing papers prepared by either of the methods above described, to avoid
this change as much as possible, more particularly if size containing alum be
used, I size the paper in a continuous sheet, and then dry it by means of
sizing and drying machines such as are more frequently used by paper-makers,
and in which the paper is caused to pass in a continuous sheet through or in
contact with the size, and afterwards over open-work or skeleton rollers in a
drying chamber. By this means the size becomes dried in so short a time
after its application, that the chemical action is stopped before it can proceed

page_text: to a very injurious extent.
In some cases, to render the size less liable to
produce discoloration, I use the acetate of alumina or the subsulphate of
alumina either entirely in lieu of alum, or mixed with a small proportion of
potass or ammonia alum, or I use any other preparations of alumina, which
are less acid than common alum. I prefer, however, a solution of acetate of
alumina, which I prepare by any of the ordinary receipts. in use among calico
printers, preferring those which produce the liquor in the least acid state. The
result of 20 lbs. of alum, 20 lbs. acetate of lead, and 2 lbs. of carbonate of
soda, prepared as aforesaid, is excellent for this purpose; and I use a quantity
of the resulting solution manufactured from 1 lb. of alum in lieu of 1 lb. of
alum used ordinarily in sizing cream or smalt blue papers, whether sized by
hand or machine. I manufacture the subsulphate of alumina by adding chalk
or carbonate of soda to a solution of of potass alum prepared as aforesaid.
I have found also that the addition of a protosalt of tin, either to the paper
pulp in cases where insoluble ferro-cyanides are used, or to the engine size,
has a tendency to reduce the amount of discoloration which the size produces;
for this propose I prefer the proto-chloridé of tin, and prefer to apply it to the
paper pulp in the engine of the paper-maker in the quantity of 2 lbs. to an
engine of rag, previously to adding the engine size, as above mentioned.
If one of the soluble in place of the insoluble ferro-cyanide, ferrid-cyanide, or
sulpho-cyanides be employed, in place of adding it to the paper pulp, it should
be added to the size used for sizing the waterleaf, and in the proportion of about
7 gallons of a saturated solution by measure, to every 100 gallons of size, and
if a soluble salt of manganese, nickel, or lead be used, it also is added to the size.
When it is desired, in place of the salts of manganese, nickel, or lead, to employ
a vegetable or animal coloring matter which is turned a diverse tint, or whose
color is destroyed by alkalies, alkaline salts, chlorine, or bromine, or their com-
pounds, I add the said coloring matter to the paper when manufactured by
printing with an engraved plate; the color I prefer for this purpose; is an ink
containing catechu; this ink I prepare by dissolving it in water and 'using it
-as a water color ink.
Method No. 2.--I incorporate in the substance of the paper, during the
process of manufacture, any soluble salt (which is not deliquescent) or any
insoluble salt. (not containing ferro-cyanogen) of manganese, lead, or nickel, in
conjunction with any animal or vegetable coloring matter or metallic color
whose tint is changed or destroyed by acids or acidulous salts or alkalies or
alkaline salts. For this purpose I prefer the phosphate, or the sulphate of
manganese, in a perfectly neutral state, in conjunction with a decoction of log-
wood set with muriate of tin or a mixture of the decoctions of logwood and

page_text: fastic set with sulphate of iron. The phosphate or sulphate of manganese
should be added to the paper pulp, or to the size respectively, as already
described, and in similar proportion, and the coloring matter and metallic salt
used to set it may be applied in the beating engine, in a proportion producing
the required depth of tint, which varies according to the strength of the dye-
woods used, and must depend upon the judgment of the paper-maker, or a
white paper may be prepared with the sulphite or sulphates of manganese
and an engraved groundwork printed on it in water color, prepared with ultra-
mine and pink madder or carmine, according to the usual receipts in use among
copper-plate printers in water colors.
Method No. 3.-I incorporate in the substance of the paper during the
process of manufacture, the ferro-cyanides, ferrid-cyanides, and sulpho-cyanides
of potassium, sodium, and amonium, in conjunction with any insoluble salt of
manganese, lead, or nickel, or any animal or vegetable coloring matter or
metallic color whose tint is destroyed or turned a diverse color by alkalies,
alkaline salts, chlorine, bromine, or their compounds, I prefer the use of the
ferro-cyanide of potassium in conjunction with the sulphite or phosphates of
manganese or a decoction of fustic set with acetate of alumina mordant, and
the sulphate of lead may be employed; the sulphite or phosphate of manganese
and decoction of fustic set with the mordant and sulphate of lead are incor-
porated in the beating engine, and the ferro-cyanide of potasium in the size.
I use about 15 to 20 lbs. of the insoluble salts to the engine of rag, and of
decoction of fustic, enough to produce a deep yellow colored paper of ferro-
cyanide of potassium, about 7 per cent. of the saturated solution, as before
described. In this method in employing vegetable colors, I carefully avoid
using in conjunction with them, Prussian blue, of which, even the accidental
formation of (in all cases in which ferro or ferrid cyanides are used) I am
most anxious to avoid, because it tends to obscure the discoloration of the paper
in any attempt to discharge ink from it by acids.
Method No. 4.-I incorporate in the substance of the paper during the
process of manufacture, the insoluble ferro or ferrid cyanide of manganese, of
the soluble sulpho-cyanide of manganese, either as single salts or combined
with potassium, sodium, or ammonium, as salts with double bases, for example,
the ferro-cyanide of manganese and potassium is such a salt with a double base.
In Method No. 4, I prefer the ferro-cyanide of manganese, or the ferro-cyanide
of manganese and potassium (which I believe are identical) which is, in a state
of purity, a white or faintly bluish white insoluble powder; this powder is
mixed in the paper pulp in the manner already described, and in the proportion
of about 20 lbs. to an engine of rag. I would remark, that while in methods

page_text: Nos. 1, 3, and 4, compounds of ferro-cyanogen, ferrid-cyanogen, and sulpho-
cyanogen are mentioned, I prefer the use of ferro-cyanides to ferrid-cyanides,
and ferrid-cyanides to sulpho-cyanides; and in Methods 1, 2, and 3, where
salts of manganese, lead, and nickel, are mentioned, either alone or in con-
junction with other substances, I very sirongly prefer those of manganese;
next in order I prefer those of lead; and last in order, nickel. This will clearly
define my preference on chemical grounds, and they will be found to give
security to the paper generally, in the order in which I name them. The
substances I have definitely described are selected on account of their cheap-
ness commercially, and this coincides remarkably with their chemical efficiency.
I am aware that it has been proposed to prepare paper by incorporating
with it in the paper-maker's engine of 140 lbs. of rag, the utmost amount of a
precipitate which can be obtained by the addition of a solution containing
amount of the precipitate that can be obtained from 1 lb: of ferro-cyanide of
potassium dissolved in water; but I have found that this precipitate when
exposed to the air becomes discolored, and it is therefore unsuited for the use
to which it was proposed to apply it; this discoloration arises from the
presence of the calcium salt when the ferro-cyanide of potassium was added.
I do not therefore claim the preparation of paper by the addition of the utmost
amount of the precipitate that can be obtained from 1 lb, of ferro-cyanide of
potassium, by adding a solution of chloride of manganese and chloride of
calcium to the paper-maker's engine, containing 140 lbs. of rag, as above
mentioned; but, since the ferro-cyanide of manganese and the ferro-cyanide of
manganese and potassium, as described in Method No. 4, can be manufactured
from the ferro-cyanide of potassium, in cases where I use a quantity of the
ferro-cyanide of manganese, or the ferro-cyanide of manganese and potassium,
as described in Method No. 4, I invariably use the utmost quantity which can
be manufactured, from at least 2 lbs. of the ferro-cyanide. of potassium to the
engine of 140 lbs. of rag, and am careful to use the maximum amount of
engine size and starch to prevent its waste, as before described, - prefering to
use a considerably larger quantity of the ferro-cyanide of manganese to an
engine of rag, as described in method No. 4. With the same object in view,
of preventing the extraction of inks from paper, I apply printers' inks and other
materials attached to the surface of paper. In this case I use the substances
mentioned in the four specified methods of making the indelible papers.
When only one substance is incorporated in the paper, as in Method No. 4,
I grind and thoroughly mix it with the printers' ink or surfacing material;
but where, as in Methods 1, 2 and 3, two substances are needful to produce
the required effect, they may be ground either in a state of mixture with the

page_text: printers' ink or surfacing material, or one substance only may be incorporated
in the paper, and the other may constitute or be incorporated in the ink printed
thereupon, or vice versa. The Method No. 3 may be varied thus:-A paper
is prepared with ferro-cyanide of potassium and a printers' ink containing a
vegetable coloring matter or mineral color, or an insoluble salt of manganese,
lead, or nickel, may be printed on the surface, which is affected by alkalies,
alkaline salts, chlorine, bromine, or their compounds.
In order in connection with these papers to render mechanical erasure in
addition to chemical, difficult or impossible, I incorporate in the substance of
the paper, according to methods well known, threads, lace, or similar fabrics
of silk, cotton, linen, or wool, in the lines where the writing of the cheque or
other document necessarily will be placed in writing. I also combine the
engraved groundworks, in particular the white line engraving, which is con-
sidered difficult to imitate, to put an obstacle in the way on an erasure. The
principle of placing between two sheets of paper a sheet of colored paper, or a
white or colored powder may also be used in connection with this paper to
prevent mechanical erasures. In order more effectually to prevent the
alteration of printed documents, either by erasure or by chemical means, I
print upon the paper, described in Methods Nos. 1, 3 and 4, where a ferro-
cyanide and a salt of manganese enter into the constitution of the paper, I
then print in an ink containing a weak solution of a caustic alkali, or any
oxidating substance; or an acid solution of any persalt of iron, in such a way
as to produce a stain penetrating from the face of the document through the
substance of the paper to the back of the document. In order to give clear-
ness to the impression, I mix a suitable thickening material to print by the
copper-plate or letter-press process. As an example of this application of the
paper, a bank note after being printed upon this paper in the usual way, may
have the amount printed as described above in duplicate, so as to render any
alteration impossible.
In witness whereof, I, the said Robert Barclay, have hereunto set my
hand and seal, this Sixth day of December, in the year of our. Lord
One thousand eight hundred and fifty-nine.
ROBERT BARCLAY. (L.S.)