AN IMPROVED FORM OF SULPHATE OF LIME, AND A SPECIAL PROCESS FOR THE PREPARATION OF THE SAME, TO BE USED AS AN ELEMENT IN THE COMPOSITION OF PAPER, AND THE FINISHING OF COTTON GOODS, AND AS A SUBSTITUTE FOR TERRA ALBA, CLAY, AND OTHER SUB- STANCES NOW EMPLOYED IN THE MANUFACTURE OF PAPER AND OTHER GOODS.
Year: 1878

page_text: LETTERS PATENT to Frederick John Cheesbrough, of the Office for Patents,
15, Water Street, Liverpool, in the County of Lancaster, Consulting Engineer,
for the Invention of "AN IMPROVED FORM OF SULPHATE OF LIME, AND A
SPECIAL PROCESS FOR THE PREPARATION OF THE SAME, TO BE USED AS AN
ELEMENT IN THE COMPOSITION OF PAPER, AND THE FINISHING OF COTTON
GOODS, AND AS A SUBSTITUTE FOR TERRA ALBA, CLAY, AND OTHER SUB-
STANCES NOW EMPLOYED IN THE MANUFACTURE OF PAPER AND OTHER GOODS.
A communication from abroad by Cornelius Tuers Tomkins, of the City and
State of New York, United States of America.
Sealed the 5th November 1878, and dated the 9th May 1878.
PROVISIONAL SPECIFICATION left by the said Frederick John Cheesbrough
at the Office of the Commissioners of Patents on the 9th May 1878.
FREDERICK JOHN CHEESBROUGH, of the Office for Patents, 15, Water Street,
Liverpool, in the County of Lancaster, Consulting Engineer. "AN IMPROVED
FORM OF SULPHATE OF LIME, AND A SPECIAL PROCESS FOR THE PREPARATION OF
THE SAME, TO BE USED AS AN ELEMENT IN THE COMPOSITION OF PAPER, AND THE
FINISHING OF COTTON GOODS, AND AS A SUBSTITUTE FOR TERRA ALBA, CLAY, AND
OTHER SUBSTANCES NOW EMPLOYED IN THE MANUFACTURE OF PAPER AND OTHER
GOODS." [A communication from abroad by Cornelius Tuers Tomkins, of the City
and State of New York, United States of America.]
This Invention has for its object a new article of manufacture to be used as an
element in the composition of paper and the finishing of cotton goods, and a special
process for the preparation of the same, the new material being used as a substitute
for terra alba, clay, or other substances now employed in the manufacture of paper.
This Invention consists in the production from native gypsum of a novel and
useful form of sulphate of lime that can be used with great profit in the manu-
facturing process referred to, and the following is a full description of the character
of the new product, and the process of its production.

page_text: Native gypsum, after being ground and dehydrated in the same manner as in the
preparation of cement, is mixed with about seven times its weight of water, i.e.,
sufficient to prevent the tendency to "setting" or hardening. It is then subjected
for about forty minutes to a process of stirring, grinding, or energetic agitation.
The result is that the finely powdered native sulphate of lime (gypsum), which at
the commencement of the treatment is an amorphous powder represented by minute
fragments of coarse rhomboidal prisms, becomes entirely changed in its crystalline
character. The sulphate of lime is found to have assumed the form of delicate
agigular crystals of microscopic minuteness, the average diameter of which is about
one fifteen-thousandth of an inch. This crystalline form, which is entirely distinct
from the original crystals of native gypsum, is in a remarkable degree fitted for use
in the inanufacture of paper, or bleached cotton goods, producing an article of
superior hardness, firmness, and opacity. The crystalline particles produced by thris
process are more minute and uniform in size than can be obtained by any other
known method, with the additional advantage, that owing to their agigular or
needle-like form, they do not escape through the meshes of the wire cloth used in
paper machinery.
If we take the ordinary material (native gypsum in the form of an impalpable
powder called terra alba), which has hitherto been used in the manufacture of paper,
and compare it with this new product by means of the microscope, we find that the
former consists of fragmentary portions of rhomboidal prisms, exceedingly variable
in size and character; the average measurements of the smaller particles being one
five-thousandth of an inch.
The same material having been treated by this process, exhibits under the
inicroscope the form of slender crysals of much greater minuteness, the great relative
length of which (as compared with their diameter) make them of essential service in
the felting or matting together of the fibre employed in the manufacture of paper.
This recrystallized gypsum has the same practical advantago over clay and other
substances, used largely at present for the same purposes, since most of them are
simply amorphous powders that cannot be interwoven with fibre, and only act to
fill up the interstices of the fabric mechanically; whilst this new product through
the delicate needle-form character of its crystals, interlaces with the fibre, thus
increasing the strength, firinness, and opacity of the fabric.
The only known substance that in crystalline character approaches this recrys-
tallized gypsum is, the chemically prepared sulphate of lime, produced by the action
of sulphuric acid, or some sulphate upon lime, or some salt of lime, but the crystals
thus formed are much coarser, and are not limited to the agigular form. Further, if
a chemically produced sulphate of lime be recrystallized by this new method, it
assumes the fine delicately crystalline form that characterizes this now material.
:

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederick John Cheesbrough in the Great Seal Patent Office on the
8th November 1878.
FREDERICK JOHN CHEESBROUGH, of the Office for Patents, 15, Water Street,
Liverpool, in the County of Lancaster, Consulting Engineer. "AN IMPROVED
FORM OF SULPHATE OF LIME, AND A SPECIAL PROCESS FOR THE PREPARATION OF
THE SAME, TO BE USED AS AN ELEMENT IN THE COMPOSITION OF PAPER, AND THE
FINISHING OF COTTON GOODS, AND AS A SUBSTITUTE FOR TERRA ALBA, CLAY, AND
OTHER SUBSTANCES NOW EMPLOYED IN THE MANUFACTURE OF PAPER AND OTHER
GOODS." A communication from abroad by Cornelius Tuers Tomkins, of the City
and State of New York, United States of America.
This Invention has for its object a new' article of manufacture to bo used as an
clement in the composition of paper and the finishing of cotton goods, and a special
process for the preparation of the same, the new material being used as a substitute
for terra alba, clay, and other substances now employed in the manufacture of
paper.
This Invention consists in the production from native gypsum of a novel and
useful form of sulphate of lime that can be used with great profit in the manufac-
turing processes referred to, and the following is a full description of the character
of the new product, and the process for its production.
Native gypsum, after being ground and dehydrated in the same manner as in the
preparation for cement, is mixed with about seven times its weight of water, i.e.,
sufficient to prevent the tendency to "setting" or hardening. It is then subjected
for about forty minutes to a process of stirring, grinding, or energetic agitation.
The result is, that the finely powdered native sulphate of lime (gypsum), which
at the commencement of the treatment is an amorphous powder represented by
minute fragments of course rhomboidal prisms, becomes entirely changed in its
crystalline character. The sulphate of lime is found to have assumed the form of
delicate agigular crystals of microscopic minuteness, the average diameter of which
is about one fifteen-thousandth of an inch. This crystalline form, which is entirely
distinct from the original crystals of native gypsum, is in a remarkable degree
fitted for use in the manufacture of paper, or bleached cotton goods, producing an
article of superior hardness, firmness, and opacity. The crystalline particles pro-
duced by this process are more minute and uniform in size than can be obtained by
any other known method, with the additional advantage that, owing to their
agigular or needle-like form, they do not escape through the meshes of the wire
cloth used in paper machinery.
If we take the ordinary material, (native gypsum, in the form of an impalpable
powder called terra alba), which has hitherto been used in the manufacture of paper,
and compare it with this new product by the means of the microscope, we find that
the former consists of fragmentary portions of rhomboidal prisms, exceedingly
variable in size and character, the average measurements of the smaller particles
being one five-thousandth of an inch.
The same material having been treated by this process, exhibits under the
microscope the form of slender crystals of much greater minuteness, the great
relative length of which, (as compared with their diameter,) make them of essential
service in the felting or matting together of the fibre employed in the manufacture
of paper.
This recrystallized gypsum has the same practical advantage over clay and other
substances, used largely at present for the same purposes, since most of them are
simply amorphous powders that cannot be interwoven with fibre, and only act to
fill up the interstices of the fabric mechanically; whilst this new product through
the delicate needle-form character of its crystals, interlaces with the fibre, thus in-
creasing the strength, firmness, and opacity of the fabric.

page_text: The only known substance that in crystalline character approaches this recrys-
tallized gypsum is, the chemically prepared sulphate of lime produced by the action
of sulphuric acid, or some sulphate upon lime, or some salt of lime, but the crystals
thus formed are much coarser, and are not limited to the agigular form. Further,
if a chemically produced sulphate of lime be recrystallized by this new method, it
assumes the fine delicately crystalline form that characterises this new material.
Since, then, there is no known process except this for producing sulphate of lime
in the form of equally delicate needle form crystals, and since it is a new product of
manufacture, I claim as the Invention communicated to me by my foreign corre-
spondent,
First. The within-described process for the preparation of hydrated sulphate of
lime, the crystalline character of which is produced by agitating calcined gypsum
with more water than is sufficient to effect simple hydration.
Second. As a new article of manufacture, the minutely crystalline form of sulphate
of lime produced, substantially as described.
In witness whereof, I, the said Frederick John Cheesbrough, have hereunto
set my hand and seal, this Seventh day of November, in the year of our Lord
One thousand eight hundred and seventy-eight.
FREDERICK JOHN (LS.)
(E.S.) QHEESBROUGH.