IMPROVEMENTS IN THE MANUFACTURE OF GLASS, WHICH INVENTION IS ALSO APPLICABLE FOR THE PRODUCTION OF OTHER HARD MATERIAL SUITABLE FOR PAVING AND OTHER PURPOSES
Year: 1880

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF GLASS, WHICH INVENTION IS ALSO
APPLICABLE FOR THE PRODUCTION OF OTHER HARD MATERIAL SUITABLE FOR
PAVING AND OTHER PURPOSES." A communication from abroad by Charles
de la Roche, of Paris, France.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 19th March 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
GLASS, WHICH INVENTION IS ALSO APPLICABLE FOR THE PRODUCTION OF OTHER
HARD MATERIAL SUITABLE FOR PAVING AND OTHER PURPOSES." [A communication
from abroad by Charles de la Roche, of Paris, France.]
This Invention relates to the manufacture of glass and other hard material from
schistous rock, such as talc-schist and the like.
Analysis has proved that this class of rocks usually contains the following
substances, namely:-Silica, magnesia, potass, soda, ferric oxide, and lime.
To manufacture plate glass and bottle glass the following mixtures or compositions
are employed, namely:-For sheet glass, silica, alumina, lime, and soda; and for
bottle glass, silica, magnesia, alumina, lime, potass, soda, and oxide of iron.
•
It will be seen from the foregoing that schistous rocks and the composition used
for bottle glass contain the same elements, excepting that there is no alumina in
the schistous rock, and alumina is more detrimental than useful.
To manufacture glass all these ingredients must be procured and united in
certain proportions, the most usual of which is the following, that is to say :-
For Sèvres glass (Dumas' analysis) silica 53-55, alumina 6·01, oxide of iron 5.74,
lime 29-22, potass 5:48. Whilst if a tale-schist is used the following combination
is found in a manner ready prepared, that is to say:-Silica 64.89, magnesia 20-58,
soda, potass, and the like 4.42, ferric oxide 9.45.
In the latter composition lime is absent, but is replaced by magnesia; in other
cases the proportion of magnesia is less and lime is present.
In carrying the said Invention in practice I take advantage of the similarity in

page_text: composition above described, and proceed as follows for the manufacture of glass
from schistous rock, that is to say :-
I take schistous earths in the state they are obtained from the mines, and I mix
them with from 20 to 25 per cent. of sulphate of soda or of potass, according to
circumstances. This proportion may be varied according to the nature of the
rocks or earth used. Oxide of lead and other substances may be added to the
composition to render the glass more like crystal, as desired. After a sufficient
calcination for the refining of the mixture has taken place a very fine glass is
produced of a density nearly equal to that of crystal, and of a beautiful emerald
green color:
This glass is easily worked, so that it can be used not only for making bottles,
but also in the manufacture of what is known as "Bohemian glass," with which it
can be favorably compared. The green color obtained by the fusion of the
substance in its normal state can be entirely removed by a few grammes of some
decolorizing matter, so that a white or colorless glass known as demi crystal is
produced, possessing the same qualities of lustre and of resistance as that heretofore
manufactured.
The glass thus obtained is proof against the action of acids, and can therefore be
used in certain special manufactures, such as the manufacture of phials for chemicals,
and bottles for champagne and other wine.
It is well known that in the manufacture of glass it is indispensable to calcine
the materials before they are put into the crucible, and in submitting talc-schists to
this process it is found that substances are evolved which under pressure readily
agglomerate, and thus furnish by their chemical composition alone excellent
refractory bodies. Moreover talc-schists by being calcined, and by the addition of
a suitable quantity of solvent, yield products varying in hardness and porosity,
and applicable for a great many uses, such as the manufacture of mill-stones,
paving-stones, and stones for filtering. This part of my Invention is connected
with the first part thereof, as the waste materials resulting from the manufacture
of the refractory substances, as herein before described, are suitable for the production
of glass.
Among the economical advantages resulting from the practice of the said
Invention are the following, that is to say:-The saving resulting from the use of
schistous rocks which hitherto have not been employed in manufactures or
commerce. Moreover when the manufacture of glass is combined with that
of refractory materials, there is a saving arising from the utilization of the
waste substances produced by the first manufacture, the said substances amount
generally to 10 per cent., and may be used as materials for the production of glass
as above explained.
Economy is also effected by reason of the omission of some of the chemical
ingredients, such as solvents, carbonate or nitrate of soda, metallic oxides, and the
like. In De Bussy's analysis of some glass mentioned by him in his well known
report on the Philadelphia Exhibition, the same was found to consist of sand
680.398, carbonate of soda 249-475, nitrate of soda 54431, lime 90-718, arsenic
3.628, manganese 0.907; whilst neither sand, nitrate of soda, lime or arsenic enters
directly into the composition of the glass made according to my said Invention, and
the proportion of the solvent used is reduced from 25 per cent. to about 13 or
15 per cent. of the whole of the composition.
The saving in fuel arising from the fact that glass made from schistous rocks is
refined in from nine to ten hours, whilst ordinary glass requires from twelve to
fourteen hours.
Furthermore my mode of operation ensures freedom from stones and other
unmelted substances, such as are ordinarily met with in bottle glass, and which
occasion a considerable amount of breakage, therefore my said Invention prevents
much loss in this respect.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the
18th September 1880.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN THE MANUFACTURE OF
GLASS, WHICH INVENTION IS ALSO APPLICABLE FOR THE PRODUCTION OF OTHER
HARD MATERIAL SUITABLE FOR PAVING AND OTHER PURPOSES." A communication
from abroad by Charles de la Roche, of Paris, France.
This Invention relates to the manufacture of glass and other hard material from
schistous rock, such as talc-schist and the like.
Analysis has proved that rocks of this class usually contain silica, magnesia
potassium, soda, ferreous oxide, and lime.
To manufacture sheet or window glass and bottle glass the following mixtures or
compositions are employed, namely:-For sheet or window glass, silica, alumina,
lime, and soda, and for bottle glass, silica, magnesia, alumina, lime, potassium, soda,
and oxide of iron.
It will be seen from the foregoing that schistous rocks, and the composition
used for bottle glass, contain the same elements, excepting that there is no alumina
in the schistous rock, and alumina is more detrimental than useful.
To manufacture glass all of these ingredients must be procured and united in
certain proportions, usually the following, that is to say :-
For Sèvres glass (Dumas' analysis) silica 53.55, alumina 6.01, oxide of iron 5.74,
lime 29.22, potassium 5.48. Whilst if a talc-schist is used, the following
combination is found in a manner ready prepared, that is to say :-Silicia 64-89,
magnesia 20:58, soda, potassium and the like 442, ferrous oxide 9.45.
In the latter composition lime is absent, but is replaced by magnesia; in other
cases the proportion of magnesia is less and lime is present.
In carrying the said Invention into practice I take advantage of the similarity
in composition above described, and proceed as follows for the manufacture of glass
from schistous rock, that is to say:-
I take schistous earths in the state they are obtained from the mines, and I mix
them with from 20 to 25 per cent. of sulphate of soda or of potassium, according to
circumstances. This proportion may be varied according to the nature of the
rock or earth used. Oxide of lead and other substances may be added to the
composition to render the glass more like crystal, as desired. After a sufficient
calcination for the refining of the mixture a very fine glass is produced of a density
nearly equal to that of crystal, and of a beautiful emerald green color. This glass
is easily worked, so that it can be used not only for making bottles, but also in the
manufacture of what is known as "Bohemian" glass, with which it can be
favorably compared. The green color obtained by the fusion of the substance in
its normal state can be entirely removed by a few grammes of some decolorizing
matter, so that a white or colourless glass known as demi crystal is produced
possessing the same qualities of lustre and of resistance or hardness as that
heretofore manufactured, especially in Bohemia.
The glass thus obtained is proof against the action of acids, and can therefore be
advantageously used in certain special manufactures, such as the manufacture of
phials for chemicals, and bottles for champagne and other wine.
It is well known that in the manufacture of glass it is indispensable to calcine
the materials before they are put into the crucible, and in submitting talc-schists
to this process it is found that substances are evolved which under pressure readily
agglomerate, and thus furnish by their chemical composition alone excellent
refractory bodies. Moreover talc-schists by being calcined, and by the addition of a
suitable quantity of solvent, yield products varying in hardness and porosity, and

page_text: applicable for a great many purposes, such as the manufacture of mill-stones,
paving-stones, and stones or blocks for filtering. This part of my Invention is
connected with the first part thereof, as the waste materials resulting from the
manufacture of the refractory substances, as hereinbefore described, are suitable for
the production of glass.
Among the economical advantages resulting from the practice of the said
Invention are the following, that is to say:-A great saving of expense by reason
of the use of schistous rocks which hitherto have not been employed for
manufactures or commercial purposes; moreover, when the manufacture of glass is
combined with that of refractory materials, there is a further saving arising from
the utilization of the waste substances produced by the first manufacture. The
said waste substances amount generally to 10 per cent. of the mass, and may be
used as materials for the manufacture of glass as above explained..
Economy is also effected by reason of the omission of some of the chemical
ingredients, such as solvents, carbonate or nitrate of soda, metallic oxides, and the
like. In De Bussy's analysis of some glass mentioned by him in his well known
report on the Philadelphia Exhibition, the same is found to consist of sand 680-398,
carbonate of soda 249-475, nitrate of soda 54-431, lime 90-718, arsenic 3.628,
manganese 0.907; whilst neither sand, nitrate of soda, lime, or arsenic, enters
directly into the composition of the glass made according to the said Invention, and
the proportion of the solvent used is reduced from 25 per cent. to about 13 or 15
per cent. of the whole of the composition.
Moreover great economy of fuel is effected for the reason that glass made from
schistous rocks may be refined in from nine to ten hours, whilst ordinary glass
requires from twelve to fourteen hours.
Furthermore this Invention ensures freedom from stones and other unmelted
substances, such as are ordinarily found in bottle glass, and cause numerous
breakages in the articles made therefrom, and loss of material arising from waste
by skimming.
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,
First. The method of manufacturing glass from tale-schist, quartzy talc, and other
analogous rocks, as and for the purpose herein before specified.
Second. The manufacture of refractory, porous, or hard substances, such as bricks,
paving-stones, filtering blocks or stones, and the like, by calcining tale-rocks, as and
for the purpose specified.
Third. The utilization, in the manufacture of glass from talc rocks, of the waste
products obtained from the manufacture of refractory and other articles by the
calcining of the said rocks, as hereinbefore described and for the purpose set
forth.
In witness whereof, I, the said William Robert Lake, have hereunto set
my hand and seal, this Eighteenth day of September, in the year of our