IMPROVE-. MENTS IN THE PRODUCTION OF WHITE OR OF SEMI-TRANSPARENT GLASS
Year: 1866

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of "IMPROVE-.
MENTS IN THE PRODUCTION OF WHITE OR OF SEMI-TRANSPARENT GLASS."-
A communication from abroad by Dr. Hugo Kunheim, of Berlin, in the
Kingdom of Prussia, Chemical Manufacturer.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on the
5th April 1866.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE PRODUCTION OF WHITE OR OF SEMI-TRANSPARENT
GLASS," a communication to me from abroad by Dr. Hugo Kunheim, of
Berlin, in the Kingdom of Prussia, Chemical Manufacturer, to be as
follows:-
My Invention consists in the production of a white or of a semi-transparent
glass, similar to the so-called enamel, milk, opal, or alabaster glass by the
employment of fluoride of aluminium, or of compounds of fluoride of
aluminium with other fluorides, such as fluorides of the alkalies, or of the

page_text: alkaline earths, or mixtures of the same in conjunction with and in addition
to the ordinary mixtures used in the manufacture of glass.
In carrying out my Invention I proceed as follows:-I mix with any of
the ordinary mixtures used for the production of glass the double fluoride of
aluminium and sodium, which I prefer to any of the other fluorides, and
which I call when in the pure and finely divided state enamel soda. I treat
such mixture in the same manner as that in which the mixture of phosphate
of lime with the ingredients suitable for the production of glass are generally
treated in the manufacture of glasses of a similar character. Amongst other
mixtures and combinations I have found that the following ingredients in
about the proportions given yield good results, viz. :-
about 25 lb. enamel soda or fluorides, as before mentioned,
"
32 lb. pearlash or soda,
"
150 lb. sand,
6 lb. chalk,
"
"
6 lb. salpetre,
"
1 lb. oxide of manganese;
but these proportions will vary according to the quality, color, and physical
character of the glass or onal it is desired to obtain.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
the said John Henry Johnson in the Great Seal Patent Office on
the 5th October 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of April, in the year of our Lord One
thousand eight hundred and sixty-six, in the twenty-ninth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said.
John Henry Johnson, Her special licence that I, the said John Henry
Johnson, my executors, administrators, and assigns, or such others as I, the
said John Henry Johnson, my executors, administrators, or 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.

page_text: and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE PRODUCTION OF WHITE OR OF SEMI-TRANSPARENT GLASS,"
a communication to me from abroad by Dr. Hugo Kunheim, of Berlin, in the
Kingdom of Prussia, Chemical Manufacturer, upon the condition (amongst
others) that I, the said John Henry Johnson, my executors or administrators,
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 John Henry Johnson, 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, that is to say:-
The said Invention consists in the production of a white or of a semi-
transparent glass similar to the so-called enamel, milk, opal, or alabaster
glass by the employment of fluoride of aluminium, or of compounds of fluoride
of aluminium with other fluorides, such as fluorides of the alkalies, in con-
junction with and in addition to the ordinary mixtures used in the manufacture
of glass.
In carrying out this Invention I proceed as follows:-I mix with any of
the ordinary mixtures used for the production of glass the double fluoride of
aluminium and sodium, which I prefer to any of the other fluorides, and
which I call when in a commercially pure and finely divided state "enamel
soda." I treat such mixture in the same manner as that in which the mixture
of phosphate of lime with the ingredients suitable for the production of glass
are generally treated in the manufacture of glasses of a similar character,
that is to say, glass of a white or semi-transparent character. I have found
that the following ingredients in about the proportions given yield good
results, viz.:-
about 25 lbs. of enamel soda or fluorides, as before mentioned,
32 lbs. of pearlash or soda,
150 of cond

page_text: I prefer to employ the fluorides of aluminium and sodium, which constitute
what I have before referred to as enamel soda, in about equivalent pro-
portions; but these proportions may be varied according to the quality of the
glass it is desired to produce..
In witness whereof, I, the said John Henry Johnson, have hereunto
set my hand and seal, this Fifth day of October, One thousand eight
hundred and sixty-six.
J. HENRY JOHNSON. (L.s.)