IMPROVEMENTS IN THE MANUFACTURE OF GLASS AND CRYSTAL
Year: 1855

page_text: LETTERS PATENT to Louis Joseph Frédéric Margueritte, Chemist, of
Paris, in the Empire of France, and of 32, Essex Street, Strand,
London, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
GLASS AND CRYSTAL."
Sealed the 18th December 1855, and dated the 27th June 1855.
PROVISIONAL SPECIFICATION left by the said Louis Joseph Frédéric
Margueritte at the Office of the Commissioners of Patents, with his
Petition, on the 27th June 1855.
I, LOUIS JOSEPH FREDERIC MARGUERITTE, Chemist, of Paris, in the Empire
of France, and of 32, Essex Street, Strand, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF GLASS
AND CRYSTAL" to be as follows, viz. :-
The object of this Invention is to manufacture silicates of potash and of soda
directly with chlorides of potassium and of sodium, so as to avoid the use of
carbonate of potash and of the carbonate and sulphate of soda.
The improved process consists in calcining with chloride of potassium or of
sodium a silicate, the base of which is capable of forming a volatile chloride;
for instance, silicate of lead, zinc, iron, &c. For this purpose I prepare proto-
silicate of lead (Pb. O, Si. 0³), or protosilicate of zinc (Zn. O, Si. O³), by heating
together one equivalent of silica with one of oxyde of lead or of zinc, the
former being fusible, and the latter remaining in the pulverulent state without

page_text: melting. One or the other of these silicates is pulverized with one equiva-
lent of chloride of potassium or of sodium, and the mixture is calcined.
Thus, at a temperature which need not be very high, vapours of chloride of
lead or of zinc will be abundantly evolved; then the developement will
decrease and finally cease, when the operation is terminated. The residue
thus formed is silicate of potash or of soda. An alkaline silicate is thus
obtained which corresponds to the metallic silicate employed, and from this it
will be easy to prepare a silicate of potash or of soda of any composition
required. Thus, by calcining bisilicate of lead or of zinc with chloride of
potassium or of sodium, I obtain bisilicate of potash or of soda. The calcination
is carried on in vessels made of the ordinary glass makers" earth, and these
vessels should be rather wide and shallow, so as to expose a great surface for
the evaporation of the metallic chloride. The operation may also be carried on
upon the sole of a furnace, the vault of which is rather low, and through
which a current of air or steam is sent for the purpose of carrying off said
vapours to a condenser in which they are stopped. The metallic chloride is
collected and dissolved or held in suspension in water, and either munipulated
in the cold state with lime or boiled with carbonate of lime, thus producing
chloride of calcium, which is eliminated by washing, and oxyde of carbonate of
lead or of zinc, both of which by the application of heat may be made to
regenerate the oxyde, which is the base of the metallic silicate, and hence forms
the principal matter of the operation.
the
The modus operandi just described is only to be considered as an example of
process, as it may be varied and enlarged upon without departing from or
dispensing with the main features of this Invention, which consist in caleining
chlorides of potassium or of sodium with silicates whose base is capable of
forming a volatile chloride; for instance, silicates of lead, zinc, of iron, &c. &c.,
thus forming frits, which being directly calcined give a clear and transparent
glass, and which being mixed and heated with monosilicate or bisilicate of
lime give the usual glass; and also in regenerating the metallic silicate, by
treating the volatilized chloride either in the cold or in the boiling state with
lime or carbonate of lime, whence a metallic oxyd or carbonate is obtained
that need only be heated with silicate in order to regenerate the silica from
which the operation started; the main object and advantage of these improve-
ments being to substitute chloride of potassium or of sodium for the carbonates
of the same bases, which are more expensive than the former. :

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Louis Joseph Frédéric Margueritte in the Great Seal Patent
Office on the 21st December 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
JOSEPH FRÉDÉRIC MARGUERITTE, Chemist, of Paris, in the Empire of France,
and of 32, Essex Street; Strand, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the 27th day of June, in the year of our Lord One
thousand eight hundred and fifty-five, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Louis Joseph Frédéric Margueritte, Her special licence that I, the
said. Louis Joseph Frédéric Margueritte, my executors, administrators, and
assigns, or such others as I, the said Louis Joseph Frédéric Margueritte, 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 THE MANUFACTURE OF GLASS
AND CRYSTAL," upon the condition (amongst others) that I, the said Louis
Joseph Frédéric Margueritte, 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 Louis Joseph Frédéric Margueritte, 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 :-
The object of this Invention is to mannfacture silicates of potash and of soda
directly with chlorides of potassium and of sodium, thus avoiding the use of
carbonate of potash and of soda.
This improved process consists in calcining with chloride of potassium or of
sodium a silicate, the base of which is capable of forming a volatile chloride,
for instance, a silicate of lead, of zinc, &. For this I prepare bisilicate of lead
(Pb. 02, Si. O³), by heating together an equivalent of oxyd of lead and two of.
silica. This silicate is reduced to a pulverulent state together with an equiva-
lent of chloride of potassium or of sodium, and the mixture is calcined thus
at such a temperature as the evolving of the chloride of lead may be as quick

page_text: as possible, yet the mass preserving its friability. During the calcining pro-
cess the mixture is to be now and then stirred, in order to facilitate the
evolving of volatile chloride. After the evolving has ceased, the residue will be
a sort of pulverulent frit, which may be used in the manufacturing of glass or
crystal; for that, it suffices to mix and caleine the said frit with a certain
proportion of silicate of lead or of lime. Crystal, which is a double bisilicate of
potash and of lead, thus may be obtained in one single calcining, for it is
unnecessary to produce separate frits. I mix and heat gradually, yet avoiding
their melting, 4 equivalents of silica, two of oxyd of lead, one of chloride of
potassium, or 2 equivalents of bisilicate of lead, 2 (Pb. 02, Si. O³), and an
equivalent of chloride of potassium (K. Cl.), hence, 2 (Pb. 02, Si. O³) + K. Cl.
Pb. 02, Si. O + K 02, Si. 03 + Pb. Cl. When the evolving of vapours has
ceased & the fusion of the mixture is determined, crystal is obtained. in the
form of fixed residue and chloride of lead, which is soon volatilized. Glass,
which may be considered as a double bisilicate of soda and of lime, is prepared
by heating in a quite similar manner,—

page_text: sodium, or from the whole mixture, containing an additional proportion of
silicate of lead or of lime. Silicates of potash and of sodium through chlorides
of potassium and of sodium are produced in a very plain manner, but such
production should not be attended with the loss or waste of metallic chloride;
such is not the case indeed, for the oxyd of lead or the oxyd of zinc is regene-
rated. As above stated, volatile chloride is carried away by a current of air or
of steam, and its flight is prevented by a condenser fitted for this purpose.
This metallic chloride is boiled with a mixture of carbonate of lime, which, by
producing a chloride of calcium, causes a precipitate of carbonate of lead or
ceruse, which may be given up to trade, or be transformed by heating into
silicate of lead by its being calcined with silica. The oxyd or metallic silicate
used at first is thus regenerated at little expense.
What has been said about oxyd of lead may be applied also to oxyd of zinc,
the use of which is more beneficial; the chloride of zinc being more volatile
than that of lead, and the equivalent of the former being about the third of
that of lead, its chemical effects are three times as great at an equal weight. It
is evident that various other terreous or metallic silicates may be obtained
through similar means; thus, chlorides of calcium, of barium, calcined with
silicate of zinc, will be transformed into silicates of lime, of baryta, and into
chloride of volatile zinc.
a
The following is the description of another means of preparing silicates of
potash and of soda for manufacturing crystal & glass:-It is well known that
high temperature is necessary to deprive clays of the water they contain, and
on this very property is grounded the decomposition of chlorides of potassium
and of sodium, and hence the production of alkaline silicates. If, indeed, a
mixture of any clay with marine salt is calcined, a quantity of chlorhydric acid
will be evolved therefrom, and the residue will contain silicate of soda and of
alumina. Let us suppose a clay of a definite composition, kaolin or porcelain
clay, for instance, the formula of which is Si. 03, A12 0, 2 HO, the reaction is
thus expressed, Si. 03, Al 03, 2 HO+ Na. Cl. Si. O³, Na. O, Al2O3 + H Cl. +
HO; the water HO substitutes the oxyds of lead, of zinc, Pb. O, Zn. O, and
the chlorhydric acid or chloride of hydrogen is evolved instead of chlorides
of lead or of zinc. Such a result is of great importance for the manufacture
of glass. Glass is made of certain proportions of silica, lime, alumen, and
soda; kaolin or any other clay will or course contain two of these elements
(silica and alumina); after its calcining with marinė salt it will contain a
third one (soda); the fourth element (lime) may be easily added, so that any
clay that is calcined with proper proportions of marine salt, of silica, and
lime must directly produce glass. However, care must be taken that silica,

page_text: .. In order to calculate the proportions of the various elements, it is necessary
to begin with the quantity of alumen contained in Souvigny glass, and say, if
8 parts of alumen require 60 of silica, how many 44 76/100 of alumen which
kaolin contains, will require? and thus, for determining the quantities of lime,
soda, consequently of marine salt, &, &, it will be found that-
296 7/10 of silica,
-
100 pounds (avoirdupoids) kaolin
-require
124 7/10 of lime,
'
29
10 of metallic oxyd;
or,
17 100 of alkalis,
323100 of marine salts,
27-37/100 of chloride of potassium.
From this notion, but still taking or suppressing from the mixture the
metallic oxyds which would have occasioned some colouring, I made number-
less experiments with chlorides of potassium and of sodium, and obtained
through them perfect transparent glass. Other clays previously analysed for the
purpose of knowing the proportions of alumen which are ever to regulate those
of the other elements (clays of Forges & Montereau) have given Ike results.
Thus, whatever may be the clay to be disposed of, it will ever be easy to
manufacture a glass of a definite composition either with basis of soda or of
potash, which in the latter case will be transformed into crystal by adding

page_text: suitable proportions of oxyd of lead. The quantity of water contained in
kaolin or porcelain clay and other clays could decompose greater quantities
of alkaline chloride, and thus much better alkalized glass would be obtained
than Souvigny glass; for instance, the various clays will supply the more
alkaline silicate the more water they contain, and thereby a more fusible glass.
This process is very plain, and requires no substantial change in ordinary
glass works. As to the saving which is to result from it, it will be clearly
demonstrated by the difference of price between chlorides of sodium, potas-
sium, and sulfates, carbonates of potash & of soda. It is yet to be observed
that the chlorhydric acid that is evolved during the operation could easily be
collected, and afford a new deduction in the expenses.
Having thus described the nature of my Invention, and the manner in which
it is or may be carried into effect, I wish it to be distinctly understood that
what I claim as novel, and being secured to me by the herein-before in parts
recited Letters Patent, is,-
Calcining chlorides of sodium & of potassium with a silicate the
elements of which are capable of forming a volatile chloride, and by using
any sort of clay; not limiting, however, the application of my process only to
manufacturing glass and crystal, but also applying it to fine and common
crockery, draining pipes, &.
In witness whereof, I, the said Louis Joseph Frédéric Margueritte, have
hereunto set my hand and seal, this Twelfth day of December, One
thousand eight hundred and fifty-five.
L. J. FREDERIC MARGUERITTE. (L.S.)