AN IMPROVED ARTIFICIAL STONE FOR GRINDING, WHETTING, OR POLISHING PURPOSES, AND A PROCESS FOR PRODUCING THE SAME." PROVISIONAL SPATION
Year: 1867

page_text: LETTERS PATENT to George Edward Van Derburgh, of the City and
County of New York, in the State of New York, and United States of
America, Gentleman, for the Invention of "AN IMPROVED ARTIFICIAL
STONE FOR GRINDING, WHETTING, OR POLISHING PURPOSES, AND A PROCESS FOR
PRODUCING THE SAME."
PROVISIONAL SPECIFICATION left by the said George Edward Van
Derburgh at the Office of the Commissioners of Patents, with his
Petition, on the 3rd April 1867.
I, GEORGE EDWARD VAN DERBURGH, of the City and County of New York,
in the State of New York, and United States of America, Gentleman, do
hereby declare the nature of the said Invention for "AN IMPROVED ARTIFICIAL
STONE FOR GRINDING, WHETTING, OR POLISHING PURPOSES, AND A PROCESS FOR
PRODUCING THE SAME," to be as follows:-
The object of my Invention is the production of grindstones, emery wheels,
whetstones, and similar articles by the combination of particles of emery,
corundum, franklinite, glass, sandstone, burrstone, or other sharp gritty
material in a suitably comminuted state, and the said Invention consists in

page_text: employing a material or composition capable of vitrefaction at a comparatively
low temperature as a flux or cementing material, to unite by its vitrefaction
any suitable gritty and cutting substances into an artificial stone or solid mass.
In producing my improved artificial stone I propose to incorporate the
emery, corundum, or other gritty or cutting substance or substances either
with a vitrescent alkaline silicate, such as the water glass of commerce, or
else with a proper proportion of clay mixed with borax, litharge, or other
material which shall serve as a flux for the clay. The mass is then to be
moulded or formed into any desired shape, with or without pressure, and
thoroughly dried by exposure to a comparatively low temperature, after which
the moulded articles are to be submitted to a more intense beat, high enough
to produce a vitrefaction of the alkaline silicate or clay, or other vitrescent
material combined with the gritty particles, and yet not sufficiently intense to
affect or impair the cutting properties of the said gritty particles. Charcoal
may be used with advantage in preparing the stone, as by its consumption in
the process of vitrefaction it will leave the stone in a porous condition, and
otherwise improve its texture. Siliea in a dry crystallised state may be used
by first reducing it with water. Air should be excluded from the ovens used
in the process during its operation. The articles must be properly packed
until vitrified, in order to prevent their warping.
SPECIFICATION filed in pursuance of the conditions of the Letters Patent,
and of an Order of the Lord Chancellor, by the said George Edward Van
Derburgh in the Great Seal Patent Office on the 12th October 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
EDWARD VAN DERBURGH, of the City and County of New York, in the-State
of New York, and United States of America, Gentleman, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of April, in the year of our Lord One
thousand eight hundred and sixty-seven, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said.
George Edward Van Derburgh, Her special licence that I, the said George
Edward Van Derburgh, my executors, administrators, and assigns, or such
others as I, the said George Edward Van Derburgh, 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,

page_text: 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 IMPROVED ARTIFICIAL STONE FOR GRINDING,
WHETTING, OR POLISHING PURPOSES, AND A PROCESS FOR PRODUCING THE SAME,"
upon the condition (amongst others) that I, the said George Edward Van
Derburgh, 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 on or before the Seventeenth day of October, One thousand
eight hundred and sixty-seven.
NOW KNOW YE, that I, the said George Edward Van Derburgh, 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:-
The object of my Invention is the production of grindstones, emery wheels,
whetstones, and similar articles by the combination of particles of emery,
corundum, franklinite, glass, sandstone, burstone, or other sharp gritty
material in a comminuted state, and my said Invention consists in employing
a material or composition capable of vitrifaction at a comparatively low
temperature as a flux or cementing material, to unite by its vitrifaction any
suitable gritty and cutting substances into an artificial stone or solid mass.
My improved artificial stone for grinding and cutting purposes may be
manufactured as follows:-The corundum or other gritty or cutting sub-
stance or substances which shall form the body of the stone having been first
ground to the fineness desired in its texture is thoroughly incorporated, either
with a vitrescent alkaline silicate, such as the "water glass" of commerce, or
the liquid silicate produced by the formula specified in the Letters Patent
granted to me by Her most Gracious Majesty Queen Victoria, on the Twenty-
fifth day of September, A.D. 1866, No. 2470, in such proportion as to pro-
duce a pasty or plastic mass, or with a proper proportion of clay and of borax,
litharge, or other flux for the clay. The' mass is then moulded or formed into
any desired shape, either with or without pressure, the effect of the application
of pressure being to produce a greater condensation of the stone. Where it is
5 desirable to use crystals of silicate, or silicate which has become hard and
dry, it is first dissolved in water, and thereafter used as above specified; or
such crystallized silicate may be mixed with gritty particles in a dry state, and
the mass be afterward brought to a proper plastic condition with water, the

page_text: proportion of dry silicate and of gritty partioles should be about one part of
powdered silica to four of emery, or its equivalent. Where clay is used instead
of silica the proportion of clay need only be just enough to fill the interstices
between the particles of emery or other gritty substance when pressed together,
and the flux thereof only sufficient to cause a partial vitrifaction of the clay;
about nine parts by weight of clay and six of borax, or its equivalent,
thoroughly mixed and rendered plastic by water will be ordinarily sufficient
for twenty-eight parts of emery or other gritty particles. A small proportion
of charcoal may be advantageously used in the manufacture of the wheels and
other articles, being added to the composition thereof before vitrifaction.
After the plastic mass of emery (or its equivalent, as set forth,) and the
necessary cementing flux (of silica or of clay and borax or other equivalents)
has been properly moulded, the articles produced are first thoroughly dried by
exposure to a comparatively low temperature, say, from 100° to 150°, and are
then submitted for about two or three hours to a more intense curing or
toughening temperature, which must be high enough to produce a vitrifaction
of the alkaline silicate, or of the clay and borax used as a flux (say, about
1,800°, or a dull red heat), and yet not sufficiently intense to affect or impair
the cutting properties of the gritty particles or portion of said articles.
The best results are ordinarily obtained by using a sand bath as the medium
of communicating the proper degree of curing and toughening heat to the
moulded articles, and air should be carefully excluded from the oven or
chamber in which the articles are cured and baked.
Having thus fully described my Invention, I claim therein as new,―
1. The combination of particles of emery or other gritty cutting materials
into an artificial stone or substance for grinding, polishing, and other purposes
by the vitrifaction or partial vitrifaction of any suitable vitrescent flux pre-
viously intermingled with said particles, all substantially in the manner
herein-before set forth.
2. The combination of sand or particles of emery, ground glass, or any
suitable gritty or cutting particles with an alkaline silicate, or with a mixture
of clay with borax, or its equivalent, or with any other vitrescent flux for the
purpose of producing an artificial grinding and polishing stone by the vitri-
faction of said flux under the influence of heat, substantially in the manner as
herein-before set forth.
3. I claim also curing and hardening a plastic combination of gritty
particles with a vitrescible flux, by first subjecting the same to a moderate
heat until dry, and afterwards to the action of a higher temperature until a

page_text: partial or entire vitrifaction of the flux is produced, substantially as herein
set forth.
In witness whereof, I, the said George Edward Van Derburgh, have
hereunto set my hand and seal, the Twelfth day of September, in the
year of our Lord One thousand eight hundred and sixty-seven.
GEORGE EDWARD VAN DERBURGH. (L.S.)