CERTAIN IMPROVE- MENTS IN THE MANUFACTURE OF VITREOUS PRODUCTS
Year: 1855

page_text: LETTERS PATENT to Louis Joseph Frédéric Margueritte, Chemist, of
Paris, in the Empire of France, for the Invention of "CERTAIN IMPROVE-
MENTS IN THE MANUFACTURE OF VITREOUS PRODUCTS."
Sealed the 6th May 1856, and dated the 12th November 1855.
PROVISIONAL SPECIFICATION left by the said Louis Joseph Frédéric
Margueritte at the Office of the Commissioners of Patents, with his
Petition, on the 12th November 1855.
I, LOUIS JOSEPH FRÉDÉRIC MARGUERITTE, Chemist, of Paris, in the Empire
of France, do hereby declare the nature of the said Invention for "CERTAIN
IMPROVEMENTS IN THE MANUFACTURE OF VITREOUS PRODUCTS" to be as follows:-
Glass, crystal, & all vitreous products obtained by fabrication, contain
potash & soda. The new vitreous composition which I use contains, like
certain glass & crystal, silica & alumina, but it contains neither potash nor
soda, which is its characteristic feature. Thus, by calcining a mixture.of-
Silica
-
65.47

page_text: described, & its application to the purposes of the different kinds of glass,
white or coloured crystal, of enamels, of earthenware glazing, & other vitreous
compositions.
As has been described, a transparent glass may be prepared without potash
nor soda, by calcining a silicate of lime & alumina. Clays, kaolin, in short
all natural substances containing silica & alumina, are thus proper to that
manufacture. Among those substances is to be found the felspath, which,
besides silica & alumina, contains potash or soda, & sometimes those two
alkalis at the same time. Potash & soda being very powerful elements of
vitrification, it becomes evident that it will be still more easy to obtain
glass with felspath which contains alkali than with clay that contains none.
Felspath, that natural source of alkali, may be employed in two different
ways for producing glass that is richer or less rich in alkali than felspath
itself. In the first case, it delivers a portion only of the required alkali; in
the 2nd case, it provides the whole which the glass must contain, without any
addition being required. No transparent glass is obtained from felspath
without a strict calculation of the alumina it contains, i.e., unless the propor-
tions of the latter are considerably lessened in the glass, a result which is
obtained with the felspath, as it has been said above with respect to clay &
kaolin. This is still the application of the same principle, i.e., by adding silica
& lime in certain proportions the felspath too rich in alumina is, as it were,
diluted.
In order to calculate the proportions of the mixture for preparing, for
example, Nemours glass & Voneche crystal, the base to be taken is the quan
tity of alumina contained in the vitreous product which is to be obtained.
Thus, for Nemours glass may be found,-
100 parts of felspath 69 silica
401

page_text: The improvement, which is the object of that part of my Patent, consists in
the use of phosphoric acid, & particularly of biphosphate of lime, for preparing
vitreous compositions in general.
It is well known that phosphoric acid, by its union with certain bases, pre-
sents fusible combinations of a perfect transparency; such are the phosphates of
potash, soda, baryta, strontium, lime, magnesia, alumina, lead, zinc, cobalt, etc.
Most of those compounds, when they are acid, are transformed by calcina-
tion into transparent glass; biphosphate or acid phosphate of lime belongs to
that number. Indeed, the biphosphate of lime, when calcined at red heat,
smelts into a kind of glass, that, as for transparency & whiteness, is by no
means inferior to glass having a base of potash & soda. Biphosphate of lime,
besides giving by itself a particular kind of glass, possesses, moreover, the
property of vitrifying completely certain substances, so as to form with them a
transparent, limpid, & colourless body. Thus, alumina, silica, kaolin, clays,
.& felspath disappear through fusion in the biphosphate of lime, in order to
.form with it combinations having the aspect & properties of crystal & glass.
Biphosphate of lime, which unites with the free bases, decomposes likewise
all their salts & combinations, whose acid or one of the elements may be vola-
tilized. Thus, it decomposes all sulphates; for example, those of baryta, lime,
strontium, magnesia, alumina, etc.; all chlorides, sulphurets, & metallic, alliga-
tions of arsenic which admits of certain natural products being used directly,
instead of prepared oxydes, such as sulphurets of lead & zinc, arsenic, sulphu-
.rets of cobalt, of nickel, etc. The sulphuric acid distils, & chlorine, sulphur,
& arsenic escape, together with the water, in the shape of chlorhydric acid,
sulphurated arsenic hydrogen, from the phosphoric acid.
The advantage of incorporating those substances with biphosphate of lime
is obvious, since they augment the quantity of glass produced at a trifling cost.
Galena or sulphur of lead, sulphate of lead, blende or sulphur of zinc, &
sulphate of zinc, may, as is evident, supersede with great economy the use of
minium, of oxyd of zinc; the sulphurated arsenics of cobalt, of nickel, & other
natural minerals may be substituted to the artificial oxyds, which are always,
comparatively speaking, at a high price. Silica, alumina, baryta, & lime being
vitrified by the biphosphate of lime, the gangue that accompanies the natural
minerals does not prevent them from combining with the biphosphate of lime.
One of the most useful properties of the biphosphate of lime with regard to
the manufacture of vitreous substances is, that it may contain considerable
quantities of iron without the glass being much coloured; this may casily be
understood, since the phosphate of peroxyd of iron is white. The phosphoric acid
may thus be considered and used as a discolouring agent of iron. Biphosphate

page_text: of lime, when calcined, produces with kaolin, oxyds or natural minerals of
lead & zinc, a very bright crystal; with those of cobalt, chromium, copper,
uranium, etc., fine glass in blue, green, & other colours, (the oxyd of uranium
produces a green colour of remarkable purity ;), that glass may be used for
doubling colourless crystal, or as enamels. I insist upon this latter property
of biphosphate of lime or phosphoric acid, because it may supersede with
great advantage the boric acid & borax in all their applications to vitreous
products, & chiefly in the preparation of enamels.
Pre-
The proportion of the mixture of biphosphate of lime with the different sub-
stances before mentioned may of courso vary much with respect to the nature,
the composition of each, & the temperature used during the operation.
liminary, experiments on a small scale must always precede the industrial
operations, according to the degrees of fusibility & coloration of the vitreous".
products to be obtained, & the success will be constant, provided the quantities:
of the strange substances added to the biphosphate of lime be not too con-
siderable, & do not go beyond the capacity of saturation of free phosphoric
acid; i. e., the vitrifying power of biphosphate of lime, which, as has been said,
is variable, according to each substance & the temperature of fusion.
Biphosphate of lime, which till now has not been manufactured on an
important scale, because it had not been applied to industry, is easily prepared.
& not expensive, by treating phosphate of lime from bones by sulphuric acid, a
precipitate of sulphate of lime being produced thereby, from which biphosphate
of lime is separated, that is, evaporated to the consistency of honey. It may be
used in the manufacture of glass in that state, but it is easy to obtain it per- .
fectly dry & in powder; it suffices to spread the honey paste on absorbing.
surfaces, for example, on dry bricks.
It must be observed, that biphosphate of lime swells by being calcined, &
that the crucibles or apparatuses of fusion that are employed must have a
sufficient capacity not to allow the matter to overflow.
The phosphate of lime that may be used for preparing biphosphate is a¸
residue from the manufacture of gelatin; it constitutes most of the black dis-
colouring residues from sugar refineries & manufactories; it is obtained
directly by calcining bones & precipitating it from urine by lime.
The sources of phosphate of lime in every country are thus numerous; & it
must be added, that there exist in Spain, at Logaosso, near Truxillo, in the
province of Estramadura, entire hills of phosphate of lime, from which that
substance might be gained in considerable quantity, &. certainly at such
moderate prices; that would prevent the rise of those of phosphate of lime.
from bones.

page_text: This latter part of my Patent has thus for its special aim the industrial.
application of phosphoric acid, of biphosphate of lime, or any other biphosphate
to the manufacture of glass, of white & coloured crystal, of the different kinds
of enamels, & of vitreous compositions in general,
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 12th May 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
JOSEPH FRÉDÉRIC MARGUERITTE, Chemist, of Paris, in the Empire of France,
send greeting.
•
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of November, in the year of our Lord
One thousand eight hundred and fifty-five, in the
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 "CERTAIN IMPROVEMENTS IN THE MANUFAC
TURE OF VITREOUS PRODUCTS," 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 tho said Letters Patent.
NOW KNOW YE, that I, the said Louis Joseph Frédéric Margueritte,
do hereby declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in and
by the following statement :-
My Invention relates to certain improvements in the manufacture of vitreous
products. It is well known that glass, crystal, and all vitreous products
resulting from trade manufactures contain potash and soda,

page_text: The improved vitreous compound for which I claim Letters Patent contains
indeed, like certain glass and crystal articles, some silica and alumen, but
neither potash nor soda, which last want constitutes the chief character of my
Invention.

page_text: Oxyd of lead -
Lime
Alumen
34.40
8.20
1.40
100.00
which only differs of the precedent one by the lime which substitutes the
potash. By melting this mixture a crystal is obtained of very nice quality.
Let it be well understood that either for glass or crystal I do not confine
myself strictly to the said proportions, but am still at liberty to add to my
vitreous composition oxyds of lead, of zinc, and other substances, the appli-
cation of which to the manufacturing of vitreous products is already known.
The intent of this part of my Letters Patent is, then, preparing a vitreous
material free from all soda and potash, and applying the same to the various
descriptions of glass, crystal, "coloured or not, to enamels or glazings for
crockery, and other like vitreous compositions.
From what has been said, it appears that by the calcination of a silicate
of lime and of alumen a transparent glass may be obtained without using
either potash or soda. Clays, kaolin, all the natural substances containing silica
and alumen, are fit for such a manufacture. Among those substances feldspath
may be classed, which contains, besides silica and alumen, potash or soda, and
sometimes these two alkalis together; potash and soda being two very powerful
elements of vitrification, it is evident that it will prove much easier to obtain
glass with feldspath which contains alkalis, than with a clay that contains
none. Feldspath in which alkali originates may be applied in two different
ways, and yield a glass which may be either richer or less rich thán feldspath
is itself with alkali. In the first case, feldspath will fetch but an odd appoint
of alkali; and in the second case, it will supply the whole necessary quantity
the glass is to contain, nor will it require any further addition. No trans-
parent glass can be obtained through feldspath unless the alumen contained in
it be strictly accounted for, or unless the same proportions of this last sub-
stance be considerably lessened in the glass, a result which is arrived at by
proceeding with feldspath, as it has been said with regard to clay and kaolin.
Here still the application of the same principle prevails; it is by the addition
of certain proportions of silica and lime that the feldspath too rich with alumen
can, as it were, be diluted..
In order to calculate the proportions of the fit mixture for preparing, for
instance, Nemours glass and Voněche crystal, a like quantity of alumen is taken

page_text: I deem it unnecessary to go beyond these quantities of oxyd of lead, which
may besides be less. However, the quantities which are likely to be pro-
ductive of the best results are from to 1 of oxyd of lead for 1 of feldspath.
In the said compounds the comparative quantity of silica to oxyds and to alkali

page_text: is very small, so that crystals are very basic, a defect that may be obviated to
by an addition of sand or silica. If, for instance, to a mixture of 1 of felds-
path and of 1 of oxyd of lead a quantity of sand is added equal to 8.37, a
crystal is obtained, which, besides the alumen it contains, is very much like
strass for its composition; the centesimal expression of which is,―

page_text: This crystal is of a suitable fusibility and adhesiveness, and can be easily
worked. But some silica may be added to the mixture, so as to transform
the oxyd of zinc into protosilicate of zinc, and produce the following
combination:-
The proportion of silica may yet be increased, so as to produce bisilicate of
zinc. These compounds yield the best qualified crystals, and well deserve to'
call the attention of manufacturers. Instead of silicate of zinc, silicate of lime.
may be added, in the proportions of 5, 10, 15 per cent. and more.
I wish it to be well understood that I do not confine myself to the propor-
tions of oxyd of lead, silicate of zinc, of lime, such as I have described; but I
claim the vitrification of feldspath from its fusion with alkaline oxyds, such as
potash and soda with terreous oxyds, such as lime, &, with metallic oxyds,
such as litharge, oxyd of. zinc, &, with addition or not of silica. Moreover,'
the vitreous products got from feldspath may be diversely tinted by the oxyds
used for that purpose. Using feldspath in the manufacturing of glass and
crystal, whether it be employed as an appoint or as a principal agent, will
prove a very important saving, considering the cost of alkalis resulting from
carbonates.
I shall now describe another part of my Invention, relating to the use of
phosphoric acid, and chiefly of biphosphate of lime, for the preparation of
vitreous compounds.
It is well known that phosphoric acid being allied to certain bases will yield
fusible combinations of a perfect translucence. Such are the biphosphates of
potash, soda, baryta, strontian, lime, magnesia, alumen, lead, zinc, cobalt, &..
By calcination most of these compounds are transformed into a transparent
glass when they are acid, such as biphosphate or acid phosphate of lime.
Biphosphate of lime being indeed calcined at a red heat will melt into a glass,
which is no less transparent and clear than any glass with basis of potash and
soda. Biphosphate of lime, besides it yields itself a particular glass, is yet apt
to vitrify certain substances so completely as to form with them a transparent;
limpid, colourless wholo. Thus, alumen, silica, kaolin, clays, feldspath melt

page_text: into biphosphate of lime, so as to form with it combinations which have both
the aspect and properties of crystal and glass. Biphosphate of lime, which
allies itself to free bases, also decomposes all their salts and other combinations,
the acid or any elements which can be volatilized. Thus, it decomposes all the.
sulphates; those, for instance, of potash, soda, baryta, lime, strontiana, &; all
chlorides, those of sodium; of potassium, &; all the sulphurets and metallic
arseniures (alligations of arsenic), which allows the direct use of certain natural
products instead of prepared oxyds, such as sulphures of lead, zinc, the arsenio-
sulphuret of cobalt, nickel, &. Sulphuric acid vaporizes, and chlore, sulphur,
arsenic evolve, under the form of chlorhydric acid, sulphurated hydrogen,
arseniated by the water of phosphoric acid..
Embodying the said substances into the biphosphate of lime will evidently
prove beneficial, for at the same time they are cheaper they increase the pro-
duct. Galena or sulphuret of lead, sulphate of lead, blende or sulphuret of:
zinc, sulphate of zinc, may be a cheap substitute for minium, oxyd of zinc..
The arsenio-sulphurets of cobalt, nickel, and other natural minerals, may be.
fitly substituted for artificial oxyds, which ever are of a price comparatively
high. Silica, alumen, baryta, lime being vitrified by the biphosphate of lime;;
the gangue attendant on natural minerals does not impede their combination.
with biphosphate of lime. One of the most useful properties of the biphosphate.
of lime, as relating to the manufacturing of vitreous products, is, that it may
contain notable quantities of iron without the glass resulting therefrom being.
sensibly coloured, and it must be so, the phosphate of peroxyd of iron being
white. Phosphoric acid may be then looked upon and used as discoloring.
agent of iron. Biphosphate of lime will yield, by calcination with kaolin, with
the oxyds or natural minerals of lead, of zinc, a very glittering crytal; with
the oxyds of cobalt, chromium, copper, uranium, &, &, beautiful glass of a
blue, green, &, tint, (the oxyd of uranium yields a green color of remarkable
clearness;) this glass may be used as coating for colourless crystals, or as
enamels. I dwell on this last property of biphosphate of lime or phosphoric
acid, as this substance, can be a cheap substitute for boric acid and borax in
all their applications to vitreous products, and chiefly to the preparation of
enamels.
The proportions of the mixture of biphosphate of lime with the various
substances I have just enumerated may of course vary, according to the
nature and composition of each, and the temperature at which it is worked.
Previous experiments must then precede the great industrial operations in
order to ascertain the degree of fusibility and coloration of the vitreous pro-
ducts that it is wished to obtain, and the operation will be attended with full:

page_text: success if the quantities of foreign bodies added to biphosphate of lime be not
too considerable, and do not exceed the saturating point of free phosphoric
acid, that is to say, the vitrifying power of biphosphate of lime, which, as has
been said, is variable, according to the nature of each substance and the tem-
perature at which the said substances melt. Biphosphate of lime, which was
not to this day the object of any important application in trade, is easily
prepared, and requires little cast in treating by means of sulphuric acid the
sulphate of lime extracted from bones, which yields a precipitate of sulphate
of lime. The biphosphate of lime is separated therefrom, and evolved till the
substance has got the consistency of honey, when it may be applied to the
manufacture of glass; but it is easy to get it in a perfectly dry pulverulent
state; for that it suffices to spread the stuff on some absorbing surface, dry
bricks, for instance. It is proper to observe that biphosphate of lime gets
bloated by calcination, and that the crucibles or melting apparatus used are to
have a suitable capaciousness for the material not overflowing. The phosphate
of lime that may be used in preparing biphosphate is a residuum from the
manufacture of gelatine, and constitutes the most part of discolouring bone
blacks, a residuum from sugar refinery works, and is directly got from calcined
bones, and from the precipitation of urines by means of lime. Phosphate of
lime may be got in all countries. In Spain, at Logrosso, near Truxillo
(Estramadura), there are whole mountains of phosphate of lime, from which
the said substance may be extracted in large quantities and at very moderate
expenses, which would for ever prevent any rise in the net cost of the
phosphate of lime extracted from bones.
This last part of my Invention specially relates to the industrial application
of phosphoric acid, biphosphate of lime, or any other biphosphate to the
manufacture of glass, crystals, both coloured or colourless, of the different
descriptions of glazings or enamels, and generally of all vitreous products.
Having thus described the nature of my Invention, and the manner in
which the same is or may be carried into effect, I wish it to be distinctly
understood that I do not confine myself to the precise details herein described,
as such may be varied or modified without departing from the principle of
action thereof; but what I claim as novel, and therefore as being secured to
me by the herein-before in part recited Letters Patent, is,—
First, preparing crystal and glass without any potash and soda by means of
silica, lime, alumen, only adding for crystal some oxyd of lead or of zinc.
Second, using feldspath, as being a cheap source of alkali for vitreous .com-
positions, and in the manner I have specified.
Third, applying phosphoric acid, biphosphates in general, and biphosphate

page_text: of lime in particular, to the manufacturing of glass, crystal, glazings or
enamels used for coating crockery or metals, and generally of all vitreous
products, the said biphosphate being apt to vitrify alumen, silica, clays, felds-
path sulphates; all alkaline, terreous, metallic chlorides, sulphates of lime, of
baryta, of lead, phosphate of lime, &, sulphurets of lead, of zinc, arsenio-
sulphurets of cobalt, of nickel, &; and also for its dissolving power over all
metallic oxyds generally used for crystals and the various coloured glazings or
enamels.
In witness whereof, I, the said Louis Joseph Frédéric Margueritte, have
hereunto set my hand and seal, this 8th day of May, in the year of
our Lord One thousand eight hundred and fifty-six.
L. J. F. MARGUERITTE. (L.S.)