AN IMPROVEMENT IN THE MANUFACTURE OF PAPER
Year: 1853

page_text: Sealed the 13th January 1854, and dated the 12th November 1853.
2 %
PROVISIONAL SPECIFICATION left by the said Thomas De la Rue
at the Office of the Commissioners of Patents, with his Petition,
on the 12th November 1853.
-I, THOMAS DE LA RUE, of Bunhill Row, do hereby declare the nature
5 of the Invention for "AN IMPROVEMENT IN THE MANUFACTURE OF PAPER"
to be as follows:-
This Invention has for its object to improve the manufacture of paper
by applying zinc white, which I find gives to paper a peculiar cha-
racter and the improvement consists of combining zinc white with
0 pulp used in the manufacture of paper.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas De la Rue in the Great Seal Patent
Office on the 12th May 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS DE LA RUE, of Bunhill Row, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of November, in the
year of our Lord One thousand,eight, hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas De la Rue, Her special
licence that I, the said Thomas De la Rue, my executors, adminis-
trators, and assigns, or such others as I, the said Thomas De la Rục,
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 THE MANUFACTURE OF PAPER," upon the condition
(amongst others) that I, the said Thomas De la Rue, by an instrument
in writing under my hand and seal, 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 Thomas 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 has, for its. object-to improve the manufacture of
paper by applying zinc-white, which I find gives to. paper a peculiar
character; and the improvement consists of combining zinc. white with
pulp used in the manufacture of paper.
Having thus stated the-nature of-my-said Invention, I will proceed
to describe the manner of performing the same.

page_text: The object of my improvement is to produce, firstly, a paper well
adapted for writing upon, from its being free from that greasiness of
surface so unpleasant, and which is often experienced in many descrip-
tions of writing papers; secondly,. to, produce a paper particularly well
adapted for either copper-plate, lithographic, or letter-press printing,
on account of the great facility with which it receives the impression;
even without previous damping; and,. thirdly, for the production of a
paper to be used for the leaves of the so-called metallic or indelible
memorandum books to be written upon with a metallic style. My
Invention consists in introducing into the pulp to be used in the manu-
facture of paper zinc white, known also by the names of oxide of zinc
and flowers of zinc, and now commonly sold in commerce. Before
using this substance I grind it to a fine pulp with water, using for that
purpose a horizontal or other mill. I employ the oxide of zinc usually
in quantities varying from five to fifty parts of dry oxide to one, hundred
parts of dry pulp, and I add thereto alum in the proportion, of one
part to every five parts of oxide of zinc; but I do not confine myself
to these proportions. I introduce the oxide of zinc through a strainer,
and the alum in solution into, the beating engine along with the requi-
site quantity of pulp in a partially beaten state, having previously shut
off the stream of water, and I cause the action of the roll to be con-
tinued for two hours, or until the oxide of zinc is thoroughly incorpo-
rated with the pulp. When this is effected, the compound pulp is run
into the chest and kept continually in motion by the agitator, so as to
prevent the deposition of the oxide of zinc. In employing this pulp
containing oxide of zinc for machine inade papers it is usually necessary
to diminish the speed of the wire, and especially when a large quantity
is used, as the water does not run away so freely as from ordinary pulp,
and the pulp "works wet"; I, however, find that the employment of
two vacuum boxes, the one before and the other after the dandy roller,
facilitates the removal of the water, and I usually cause a somewhat
less vacuum to be maintained in the first than in the second vacuum
box. I would remark that more care than ordinary is required on the
part of the workman in regulating the speed of the wire, but at the
same time the difficulties are readily overcome by attention.
I would

page_text: state that the quantity of zinc white used for printing papers depends on
the quality or absorbent character of paper desired to be obtained, and
I use for printing papers from five to fifty parts of dry oxide of zinc
to one hundred parts of dry pulp. I find that the more oxide of zinc
which can be introduced without making the paper too tender the
better the printed impressions obtained. In writing papers from ten
to twenty parts to the hundred of pulp are preferred, and metallic books
I use from thirty to upwards of fifty parts of oxide of zinc to one
hundred parts of pulp.
I would here state that I am aware that in a Specification of a Patent
granted to my son and partner, Warren De la Rue, a claim is made
for the application of oxide of zinc on to the surface of manufac-
tured paper and cardboard; I do not therefore claim such an applica-
tion of oxide of zine; but what I do claim is, the incorporation of oxide
of zinc with pulp in the process of manufacturing paper.
In witness whereof, I, the said Thomas De la Rue, have hereunto
set my hand and seal, this Twelfth day of May, in the year of
our Lord One thousand eight hundred and fifty-four.
Witness,
GEO. PITT,
4, Old Square.
THOMAS DE LA RUE. (L.s.)