IMPROVEMENTS IN THE MANUFACTURE OF GLASS WARE.
Year: 1874

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Patent Agents, Southampton Buildings, London, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF GLASS WARE.".
A communication from abroad by Carl Pieper, of Dresden, Saxony,
Civil Engineer.
Sealed the 15th June 1875, and dated the 18th December 1874.
COMPLETE SPECIFICATION filed by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 18th December 1874, pursuant to the 9th
Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF GLASS WARE," and have petitioned Her Majesty to
grant unto me, my exccutors, administrators, and assigns, Her Royal

page_text: Letters Patent for the same, and have made solemn Declaration that
it has been communicated to me from abroad by Carl Pieper, of Dresden,
Saxony, Civil Engineer.
NOW KNOW YE, that I, the said William Robert Lake, do hereby
declare that the following Complete Specification, under my hand and
scal, fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed in and by the following
statement :-
The object of this Invention is to increase the tenacity and hardness
of articles made of glass of any composition whatever. I attain this 1
object by dipping the glass ware after its manufacture in a highly heated
state into a liquid also heated to a certain temperature, which latter is
dependent on the composition and the melting point of the glass to be
treated.
In general the temperature of the aforesaid liquid, which may be 1
called "tempering liquid," is to be comparatively higher for glass having
a higher melting point. As tempering liquid for glass having the lowest
melting point, such as cryolite glass, or the silicates of potass and lead
(flint glass) I employ any sort of oil, melted fat (by preference tallow),
or melted paraffine heated to a temperature of from 240 to 280 degrees
centigrade. I also use glycerine with great advantage, as its temperature
can be elevated to and maintained regularly at its boiling point of 250
degrees centigrade.
For glass consisting of the silicates of potass and lime, or of the more
fusible silicates of soda and lime, the temperature of the tempering
liquid must be from 325 to 340 degrees centigrade, and in this case I
prefer to employ sulphuric acid heated up to its boiling point or
nearly so!
For tempering the less fusible silicates of soda and lime, melted
saltpetre or a melted alloy of antimony and tin has to be used, the
points of fusion of which lie at from 340 to 380 degrees centigrade, and
for the hardest glass, as crown glass or the like, manufactured out of the
silicates of beron or of baryte, an alloy of lead and antimony with a
melting point at about 400 degrees centigrade is requisite.
Other alloys or substances having a melting point similar to the above
named, or which can be heated to the point required without being
evaporated or decomposed may be applied for the purpose in question.

page_text: The glass so treated, and which I have called "vulcan glass" shows
a superior degree of hardness, a great resistance to a sudden change of
temperature, and a tenacity which may become forty times as great as
that of common glass.
Having thus fully described the said Invention, as communicated to
me by my foreign correspondent, and the manner of performing the
same, I wish it understood that I claim, the tempering or hardening of
glass of any sort whatever by heating the same to a temperature near its
point of fusion, and then dipping it into a liquid heated to a certain
lower point of temperature dependent upon the chemical constitution of
the glass and the heat conducting power of the liquid, and for which
liquid oil, melted tallow or other fat, or paraffine, glycerine, sulphuric
acid, melted saltpetre, and melted alloys of antimony and tin, or of
antimony and lead, or such other substances as have an equivalent
faculty of assuming or maintaining a liquid stato- at temperatures of
from 230 to 400 degrees centigrade may be employed, as and for the
purpose described.
In witness whereof, I, the said William Robert Lake, have herc-
unto set my hand and scal, this Eighteenth day of December, in
the year of our Lord One thousand eight hundred and seventy-
four.
Witness,
JA'. EDWARDS,
8, Southampton Buildings,
London.
W. ROBT. LAKE. (L.S.)