IMPROVEMENTS IN PREPARING THE SURFACES OF PAPER AND CARD BOARD
Year: 1852

page_text: LETTERS PATENT to Warren De la Rue, of Bunhill Row, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN
PREPARING THE SURFACES OF PAPER AND CARD BOARD."
Scaled the 19th February 1853, and dated the 21st December 1852.
PROVISIONAL SPECIFICATION left by the said Warren De la Rue.
at the Office of the Cominissioners of Patents, with his Petition,.
on the 21st December 1852.
J, WARREN DE LA RUE, of Bunhill Row, in the County of Mid-
dlesex, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PREPARING THE SURFACES OF PAPER AND CARD BOARD"
to be as follows: _
This Invention consists of applying the oxide of zinc in producing
enamelled surfaces to paper and card board; and also in the prepa-
ration of paper to be used in meinorandum books to be written on
with metallic stiles or points.

page_text: SPECIFICATION in pursuance of the conditions of the Letters
Patent, filed by the said Warren De la Rue in the Great Seal
Patent Office on the 20th June 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
WARREN DE LA RUE, of Bunhill Row, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of December, in
the year of our Lord One thousand eight hundred and fifty-two, in
the sixteenth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Warren De la Rue, Her
special licence that I, the said Warren De la Rue, my executors,
administrators, and assigns, or such others as I, the said Warren
De la Ruc, ny 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 PREPARING THE SURFACES OF PAPER
AND CARD BOARD," upon the condition (amongst others) that I, the
said Warren De la Rue, by an instrument in writing under my hand
and scal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the saine 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 Warren De la Rue, 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 consists of applying the oxide of zinc in producing
enamelled surfaces to paper and card board, and also in the pre-
paration of paper to be used in memorandum books to be written
on with metallic stiles or points.
And in order that my said Invention may be most fully under-

page_text: stood and readily carried into effect, I will proceed to describe the
means pursued by me.
Heretofore it has for the most part been usual, when enamelling
card board, to employ that carbonate of lead known in commerce
as "Kremnitz White," which, like all compounds of lead, is more or
less injurious to the health of the workmen employed; and enamelled
surfaces so produced are liable to be discolored in the presence of
sulphuretted hydrogen and other sulphurets. Now, by applying
oxide of zinc (or zinc white), not only is the working of it scarcely
if at all injurious to the workmen employed in laying it on the paper
or card board, but the enamelled surfaces produced with it are not
liable to be injured in color by the ordinary uses to which they are
applied, as are the enamels produced by the use of compounds of lead..
In carrying out my Invention, I have found that it is very impor-
tant that the oxide of zinc or zinc white used should be well ground
in water; and, in preparing it for this process, I have found that the
best mill is that for which Letters Patent were granted to Charles
Jack on the Twenty-ninth March, One thousand eight hundred
and fifty-two; and I have found it desirable to pass the oxide of
zinc or zinc white through the mill two or three times, using as
little water as may be; and I prepare an enamel by mixing such
ground zinc white with a solution of gelatine, for which purpose I
employ, at the rate of about eight pounds of the wet zinc white as
it comes from the mill with two pints of a strong solution of gela-
tine (containing one fourth part of its weight of dry gelatine) and
three pints of water. This preparation, after it has been passed
through a fine sieve, I apply to the surface of card board with
brushes in a similar manner to that practised for lead enamel, ap-
plying from two to four coats on the face, and one or more on the
back; but when applying it to paper I generally use only one coat
or two coats on the face only. I would remark that, in getting the
polish to such surfaces, it is important to avoid the use of copper
plates in the milling till the polish has been partly obtained by
other means, otherwise the copper plates are very likely to mark
the zinc surface; I, therefore, usually polish card board or paper
coated with zinc oxide by pressing the same between glazed boards,

page_text: and then the pressure of the engraved plates of copper or steel in
the process of printing gives the finishing polish; but I may state,
that copper plates are generally used for giving the finishing polish
in case the enamelled card board or paper is not intended for copper
plate printing.
The property which zinc enamel has of being readily marked by
copper and other hard metals, renders it peculiarly applicable as
a surface, when combined with paper or card board, for making
imemorandum books, as it admits of harder stiles or points being
used, and which will be found more lasting than those now used for
writing on surfaces prepared by other modes or with other materials;
and I, therefore, employ by preference stiles or points of copper, or
alloys of copper, for such purposes. In preparing paper for memo-
randum books, as it is not necessary to have so high a polish as on
the other enamelled papers, I use double as much water to that
above given; (that is to say) to eight pounds of wet zinc oxide I use
two pints of strong size and six pints of water.
Having thus described the nature of my Invention, and the best
means I am acquainted with for performing the same, I would have
it understood that I do not confine myself to the precise details
herein described; but what I claim is, the applying oxide of zinc in
producing enamelled surfaces to paper and card board, and also the
application, amongst others, of the enamelled card board and paper
so prepared to the manufacture of the so called metallic memo-
randum books and tablets.
In witness whereof, I, the said Warren De la Rue, have
hereunto set my hand and seal, this Eighteenth day of June,
in the year of our Lord One thousand eight hundred and
fifty-three
WARREN DE LA RUE. (L.S.)
Witness,
W. J. RIDEOUT, Farnworth.