IMPROVEMENTS IN THE MANUFACTURE OF GLASS
Year: 1861

page_text: LETTERS PATENT to Tony Petitjean, of 4, Brydges Street, Covent Garden,
in the County of Middlesex, Chemist, for the Invention of " IMPROVE-
ㄨ
Sealed the 30th August 1861, and dated the 5th March 1861.
PROVISIONAL SPECIFICATION left by the said Tony Petitjean at the
Office of the Commissioners of Patents, with his Petition, on the 5th
March 1861.
I, TONY PETITJEAN, of 4, Brydges Street, Covent Garden, in the County of
Middlesex, Chemist, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF GLASS," to be as follows:-
My improvement consists of compressing the glass bulb between two discs
perfectly even and plane, so as to give to the glass, by a same and first process
the spreading which has been hitherto obtained by a second and laborious
process. Moreover, the pressure of the discs upon the air contained in the
glass bulb or cylinder gives a power of several atmospheres, which power is
used by the glass blower, by stopping with his thumb the opening of his blow
pipe to prevent all escape, and then the man, by an intelligent management of
this power, is able to give to the glass the desirable precision, it being observed
that the bulb must be made by the glass blower without any oscillation and
waving. The above-mentioned discs are made of metal, stone, clay, wood, or

page_text: carbon. If metal is used I obtain a perfectly even surface by depositing upon
a plate glass some gold, silver, or platina, according to my process previously
patented on the 24 July 1855, No. 1681, then lining this deposit with a
thick copper coating by means of the galvanic battery. I afterwards with-
draw from the plate glass the so obtained metallic surface. If stone or clay
is used I polish it by the ordinary means. Metallic, stone, or clay discs must
be heated for working. If wood is used I diminish its scorching and wear
and tear by keeping it, when not worked, in a solution of organic bodies or
liquids, and by wetting it with the same solution after every operation. But
to metal, stone, clay, or wood, I prefer carbon, which has never hitherto been
used for such purpose, and the application of which to the manufacture of
glass in general, glass ware included, I claim as my Invention. I prepare the
carbon by mixing some pulverized carbon with any substance of a sticky and
cohesive nature that may give to the said carbon the required compactness,
solidity, and fineness. I may also use the carbon which is naturally formed in
the gas retorts.
My prepared carbon has, over all the other materials, many advantages, the
principal of them being its smoothness and unalterableness, and besides, it
does not cool the glass, and bears very well the heat produced by the hot glass.
The discs are kept in a circular and counteracting motion in the same time
that they advance towards each other. This is obtained by means of gearing,
the discs being led forwards and backwards by puppets put in motion by the
said gearings.
I also, by my new process, obtain round and oval glass cylinders, it being
observed that the bringing together of the discs or plates is, relatively to
the given plane surfaces, in the same ratio as the diameter is to the circum-
ference.
By my process I manufacture every sort of glass,-plate glass, window
glass, reflectors, lenses, and any glass for optical purposes. As regard lenses;
I obtain hollow glass, which may be afterwards filled with any refracting
liquid. For the manufacture of glass ware I use my prepared carbon for
making moulds.
Although I prefer the circular motion above described, I also use the
vertical and horizontal to-and-fro motion, and in this case the plates may be
of any other shape than discs.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Tony Petitjean in the Great Seal Patent Office on the
5th September 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, TONY
5 PETITJEAN, of 4, Brydges Street, Covent Garden, in the County of Middlesex,
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifth day of March, in the year of our Lord One
thousand eight hundred and sixty-one, in the twenty-fourth year of Her
O reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Tony Petitjean, Her special licence that I, the said Tony Petitjean,
my executors, administrators, and assigns, or such others as I, the said Tony
Petitjean, 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
5 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 MANU-
PACTURE OF GLASS," upon the condition (amongst others) that I, the said Tony
Petitjean, my executors, or administrators, by an instrument in writing, under
my, or their, or one of their hands and seals, 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 Tony Petitjean, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
My improvements consist of compressing the glass bulb between two discs
perfectly even and plane, so as to give to the glass, by a same and first process,
the spreading which has been hitherto obtained by a second and laborious
process. Moreover, the pressure of the discs upon the air contained in the
glass bulb or cylinder gives a power of several atmospheres, which power is
used by the glass blower by stopping with his thumb the opening of his blow
pipe to prevent all escape, and then the man by an intelligent management of
this power is able to give to the glass the desirable precision; it being
observed that the bulb must be made by the glass blower without any
oscillation and waving. The above-mentioned discs are made of metal, stone,

page_text: clay, wood or carbon. If metal is used, I obtain a perfectly even surface by
depositing upon a plate glass some gold, silver, or platina, according to my
previously patented process; then lining this deposit with a thick copper
coating by means of the galvanic battery. I afterwards withdraw from the
plate glass the so obtained metallic surface. If stone or clay is used, I polish
it by the ordinary means. Metallic stone or clay discs must be heated for
working. If wood is used, I diminish its scorching and wear and tear by
keeping it bathing when not worked in a solution of organic bodies or liquids,
and by wetting it with the same solution after every operation. But to metal,
stone, clay, or wood, I prefer carbon, which has never hitherto been used for
such purpose, and the application of which to the manufacture of glass in
general, glassware included, I claim as my Invention. I prepare the carbon
by mixing some pulverized carbon with any substance of a sticky and cohesive
nature that may give to the said carbon the required compactness, solidity,
and fineness. For that purpose I use tar distilled from wood. I treat it by
heating and vapourization until it is reduced to a state in which, when cooled,
it may be easily pulverized. I then mix one part of the powder obtained
from the tar with one part and a half to two parts of pulverized charcoal ;
care being taken that both powders may be as fine and the mixture as
complete as possible.
Now to prepare the discs I make use of a cast-iron box, rather similar in
form to a snuff-box, and being two, three, or four feet in diameter, and six or
seven inches in height. I fill this box with the above-mentioned mixture,
which I strongly compress. I close the box with a cover made of the same
metal, and I put it in an oven heated to about 300 degrees Fahrenheit, main-
taining this heat as regularly as possible for 24 to 30 hours. After which the
heat is increased to 450 to 500 degrees Fahrenheit, maintained with the same
regularity for 20 to 24 hours. The portion of tar still susceptible to be
volatilized has then become almost completely volatilized. The oven is then
heated to a dark red, after which the mixture is left to cool down. The finer
the powders are the more compact the carbon obtained is. Soft or hard
carbon is obtained according to the softness or the hardness of the wood the
charcoal is made of. The greater the heat the more the hardness of the
carbon increases by the greater reduction it attains in the heating. An addi-
tion to the ratio of tar increases the hardness. The mode of heating I have
herein-before prescribed is indespensable, because were the heat of the oven
gradually increased, a kind of crust would be formed, which surrounding and
covering the still clammy matter in the middle, would be an obstacle to the
regularity of the shrinking, and the carbon thus obtained would not be of one

page_text: piece. Instead of charcoal I may also use the carbon which is naturally
formed in the gas retorts.
My prepared carbon has, over all the other materials, many advantages,
the principle of them being its smoothness and unalterableness; and besides, it
does not cool the glass, and bears very well the heat produced by the hot glass.
The discs are kept in a circular and counteracting motion, in the same time
that they advance towards each other. This is obtained in the following
manner, as will be better explained by a reference to the annexed Drawings:-
The Figure 1 is a plan of the machine; the Figure 2 is a side view of the
same. A, A', is a rectangular cast-iron frame, strongly bolted to two cubic
blocks of stone R, R', the superior surface of which must be perfectly hori
zontal all along the length of the frame, and on both sides run two rails S, S',
the external sides of which are inclined down at an angle of 30 to 40 degrees.
This inclined face, and also the superior and horizontal face of the rails, must
be perfectly levelled on the plaining machine, and afterwards polished. Two
puppets P, P, much like the puppets of an ordinary lathe, slide on the rails
towards each other, and backwards, as follows:-The middle of the frame is
traversed in its whole length by a shaft T, strongly fastened at both ends E, E',
Figure 2. This shaft has a bevil wheel G, being in gear with another bevil
wheel H, fastened to the shaft F, F, which ends with a wheel D, serving as a
crank, and giving the motion to the gearings. The shaft T is also provided with
two threads L, L', corresponding with screws of the puppets. By turning the
crank wheel D, the puppets are thus moved forwards and backwards on the
rails. Each puppet is traversed in its upper part by mandrels M, M', perfectly
cylindrical, bearing on two collars, in which they must turn with the greatest
precision. On the ends of these mandrels is a circular forged plate O, O¹,
being at least 12 to 15 inches in diameter, and the faces of which is carefully
turned in the lathe. Upon these plates are strongly bolted two cast-iron discs
Q, Q, the back of which is also well turned in the lathe, and is made to stick
against the plate; the discs of carbon B, B', are fixed to the cast-iron plate by
means of melted bitumen spread over the disc and plate, which are then united
together and heated till they are completely adhérent. They are then left to
cool down, and afterwards affixed on the plate of the lathe. The mandrels
M, M', have pullies C, C', in communication through a strap with a driving
shaft which thus can give a rapid circular and counteracting motion to the
discs. To secure the greatest precision the discs must be fitted when in place,
and then perfectly levelled. This is obtained by means of a plate of glass
unpolished on both sides, to which a reciprocating motion is given; whilst the
discs revolve by a counteracting motion, one on the left and the other on the

page_text: right. The parallelism of the discs must always maintain a great precision,
whether they simply revolve or whether they advance towards each other.
Although I prefer the circular motion above described, I also use the vertical
and horizontal to-and-fro motion, and in this case the plates may be of any
other shape than discs.
The working of my process is as follows:-The glass-blower makes his bulb
as usual, but in a carefully turned and polished block made of my prepared
carbon, so that it should leave no bad impress to the glass when the glass-
blower makes it turn in the block. Then he makes his cylinder as usual, and
taking advantage of the heat of the glass he brings it between the discs of
carbon which revolve rapidly, whilst a man moving the crank brings the discs
quickly one towards the other, and thus compresses the glass cylinder until the
discs are at a no greater distance from each other than a half of an inch or an
inch. During this operation the glass-blower stops with his thumb the orifice
of his pipe, thus producing a considerable pressure, which can reach several
atmospheres; for as the flattening of the cylinder diminishes by degrees its
former capacity, in the same time it produces a greater pressure. The glass-
blower may take a great advantage of the so obtained power, which he will
easily regulate at will by opening with his thumb a passage to the air con-
tained in the cylinder. It is easily understood that two sheets are obtained at
once by this process. The flattened cylinder is immediately brought in an
annealing furnace, from which it is removed after two hours, as in the manu-
facture of oval cylinders. The flattened cylinder is cut with a diamond all
along its circumference, and is thus opened in two, and forms two sheets.
¡
The glass produced by a flattened cylinder has always undulations somewhat
resembling the surface of the water agitated by a breeze. These undulations
or wavings are formed by the glass-blower oscillating the bulb in order to
lengthen the cylinder. To obviate this inconvenience, instead of blowing a
cylinder to be flattened I blow a ball, which is afterwards flattened by the
same process. In this case the sheets of glass are round, as in the manu-
facture of the crown glass. It is easy to make the calculation of the width of
the sheets of glass, as the rule to be followed is the relation of the diameter to
the circumference. For instance, a distance of seven inches between the discs.
gives a plain surface of twenty-two inches, consequently nothing is easier than
to regulate the work.
To obtain oval cylinders I substitute for the discs rectangular plates made
with my prepared carbon that most advantageously replaces the wood planks
'usually used in this sort of manufacture, with two somewhat large plates made
of carbon. Every size may be manufactured, for it suffices to adapt them to

page_text: my machine, after having stopped the rotary motion, and then to put them at
the required distance. The same should be done to produce lenses of a some-
what large size, or convex mirrors, or reflectors, by replacing the plane discs
by concave discs. As regards the lenses, they should be filled with a solution
of sulphate of zinc, or any other solution possessing a great refracting
power.
For the manufacture of glass wares I use cylindrical casings of thin cast
iron or zinc, in two parts, susceptible of being opened and closed by means of
hinges, and provided with a handle as for the moulds actually used."
According to the size of these moulds I make with my prepared carbon cylin-
ders, which I turn to the size of the cylindrical casing, and to which I give
the desired shape with the lathe, exactly as it is now done with the wood, and
I fix the so shaped carbon to the casing of cast iron or zinc, which serves to
give to these moulds the required solidity. They are used as would be the
wooden moulds, of which they have all the qualities, without partaking of their
inconveniences. They are wetted during the work, and can be used inde-
finitely. The blocks for the use of glass-blowers are prepared in the same
manner. One could mould directly with the matters used for the preparation
of my carbons; care being taken to wet them with naptha, or any other similar
substance, in order to facilitate the operation; but the shrinking of the carbon
when submitted to heat, would not allow to obtain the required sizes.
As none of the other modes indicated by me possesses the whole of the
advantages which I obtain by the use of the carbon, I do not give the special
processes for the materials other than the carbon, limiting my claim in these
cases to my method of flattening or compression of the glass.
Having described the nature of my Invention, and the manner of performing
the same, I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent, is,-
First, the use of machine generally for the manufacture of glass in plane
or curved sheets, by making use of the pressure produced by the interception
of the air contained in the blown piece when the said piece is mechanically
compressed.
Second, the use of the special machine, the designation and Drawings of
which I give, or of any other machine based upon the same principle, that is
to say, of moving against each other two plates having an horizontal, vertical,
or circular motion.
Third, the use of carbon generally, and most especially of the charcoal for
the manufacture of glass in general.
Fourth, the above described process of preparation of the said charcoal,

page_text: including, of course, my process of heating, by which I obtain carbon of one
piece without any crack.
Fifth, the moulds for glass wares, and the blocks for the use of the glass-
blowers, as indicated by me.
Sixth, the use of the plates in the manufacture of oval cylinders.
Seventh, the specified process for the manufacture of lenses.
In witness whereof, I, the said Tony Petitjean, have hereunto set my
hand and seal, this Second day of September, in the year of our Lord
One thousand eight hundred and sixty-one.
TONY PETITJEAN. (L.S.)