IMPROVEMENTS IN HARDENING GLASS AND OTHER SUB- STANCES, AND THE APPLICATION OF SUCH HARDENED SUBSTANCES TO VARIOUS USEFUL PURPOSES.
Year: 1874

page_text: LETTERS PATENT to John Macintosh, of Westminster, Civil Engineer,.
for the Invention of "IMPROVEMENTS IN HARDENING GLASS AND OTHER SUB-
STANCES, AND THE APPLICATION OF SUCH HARDENED SUBSTANCES TO VARIOUS
USEFUL PURPOSES.”.
Sealed the 26th February 1875, and dated the 28th August 1874.
PROVISIONAL SPECIFICATION left by the said John Macintosh
at the Office of the Commissioners of Patents, with his Petition,
on the 28th August 1874.
I, JOHN MACINTOSH, of Westminster, Civil Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN HARDENING
GLASS AND OTHER SUBSTANCES, AND THE APPLICATION OF SUCH HARDENED SUB-
STANCES TO VARIOUS USEFUL PURPOSES," to be as follows:-
My present Specification refers to improvements on an Invention for.
which Letters Patent were granted to me dated 14 May 1874, No. 1714,
for hardening iron; steel, or alloys, and which consists of pouring molten.
metal in small portions into moulds, the temperature of which moulds

page_text: has been reduced to the lowest attainable freezing degree. The effect of
which treatment is to harden the substances so as to render them
capable of being used as cutting nibs or points for tools used for boring
and drilling rocks, and for cutting and dressing stone, as well
also to saws, and other dressing tools; the object being to substituto
these hardening cutters in lieu of diamonds and diamond dust now
usually employed for boring, drilling, and cutting rocks, and other
hard substances.
Now I have discovered since the date of the above Patent that glass,
graphite, uncrystallised carbon, slag, and other analagous substances,
may be hardened by means similar to those described in my former
Specification, and when these last named substances are so hardened
they may be used for a variety of useful purposes as well as for boring,
cutting, and drilling. For instance, colored glass may be so hardened
and used as a substitute for gems. These hardened substances may
also be reduced to powder, and used in the same manner as diamond
dust, or as emery powder, and when mixed with hard or soft vul-
canised india-rubber may be used as wheels or files for cutting and
polishing.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Macintosh in the Great Seal Patent Office
on the 27th February 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JoпN
MACINTOSH, of Westminster, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-eighth day of August, in the
year of our Lord One thousand eight hundred and seventy-four, in the a
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Macintosh, Her
special license that I, the said John Macintosh, my executors,

page_text: administrators, and assigns, or such others as I, the said John
Macintosh, 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 HARDENING GLASS AND OTHER SUBSTANCES, AND THE
APPLICATION OF SUCH HARDENED SUBSTANCES TO VARIOUS USEFUL PURPOSES,"
upon the condition (amongst others) that I, the said John Macintosh,
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 Offico within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Macintosh, 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:―
My present Specification refers to improvements on an Invention for
which Letters Patent were granted to me dated 14th May 1874, No.
1714, for hardening iron, steel, or alloys, and which consists of pouring
molten metal in small portions into moulds, the temperature of which
moulds has been reduced to the lowest attainable freezing degree. The
effect of which treatment is to harden the substances so as to render
them capable of being used as cutting nibs or points for tools used for
boring and drilling rocks, and for cutting and dressing stone, as well
also to saws and other dressing tools; the object being to substitute
these. hardened cutters in lieu of diamonds and diamond dust now
usually employed for boring, drilling, and cutting rocks, and other
hard substances.
Now I have discovered since the date of the above Patent that glass,
graphite, uncrystallised carbon, slag, and other analogous substances,
may be hardened by means similar to those described in my former
Specification, and when these last named substances are so hardened
they may be used for a variety of useful purposes as well as for boring;
cutting, and drilling. For instance, colored glass may be so hardened

page_text: e
and used as a substitute for gems. These hardened substances may
also be reduced to powder and used in the same manner as diamond
dust or as emery powder, and when mixed with hard or soft vul-
canised india-rubber may be used as wheels or files for cutting and
polishing.
In some cases my process is applicable to hardening the teeth of
ordinary saws, which is effected after they are made by inserting the
teeth only in the refrigerated moulds.
In hardening the substance the method I pursue is to place a small
quantity of fused or nearly fused clear or colored glass into iron
or other moulds to shape the glass, and the substance is taken out of
the moulds and placed in platinum moulds, and is fused or nearly fused
and suddenly deprived of its caloric by frigorific mixtures of iced water
and salt, or any of the freezing compounds that produce extreme cold.
The conponent parts of gems are treated by the above process, and I am
enabled to produce thereby factitious gems even harder than real
diamonds.
In treating powder or sand obtained from corundum, emery, glass, or
natural sand, I subject them to a dull red heat, and immerse them in
iced water and salt, which suddenly abstracts the caloric, producing
extreme hardness and sharpness.
In treating armour plates, the outside or striking surface is chilled
only by suddenly abstracting the heat in moulds filled with powdered
soapstone or plumbago, reduced to extreme extreme cold by passing iced
water and salt under the mould. In the case of horse shoes I chill only
the parts that come in contact with the stones in the same manner as
herein-before described.
The application of my hardened substances may be extended to a variety
of useful purposes, and it is obviously unnecessary to enumerate all the
applications which may be made of them, and the operation is so
simple that any skilled workman, mechanic, or chemist, employed in
manufactures, will readily understand how to produce and apply the
chilled substances.
Having now set forth the nature of my Invention and how the same
may be carried into practice, I desire it to be understood that I claim
under the herein-before in part recited Leters Patent is,―

page_text: Firstly. The process of hardening glass sand made from emery,
corundum, natural sea sand, and glass sand, as herein-before described.
Secondly. I claim the process herein-before described for the manu-
facture of factitious gems.
Thirdly. I claim the hardening of armour plates and parts of horse
shoes, by the process herein-before described.
Fourthly. I claim the use of these hardened substances when powdered
and mixed with vulcanised india-rubber, hard or soft, or with other
materials, as wheels or files for polishing or sharpening.
And, Lastly. I claim the use of such hardened substances for a variety
of useful purposes.
In witness whereof, I, the said John Macintosh, have hereunto set
my hand and seal, this Twenty-seventh day of February, in the
Witness,
CHARLES BARLOW,
Patent Agent,
23, Southampton Blds,
W.C.
JOHN MACINTOSH. (L.S.)