IMPROVE- MENTS IN THE MANUFACTURE OF GLASS
Year: 1863

page_text: PROVISIONAL SPECIFICATION left by Eugène Rascol at the Office of the
Commissioners of Patents, with his Petition, on the 14th December
1863. A communication from abroad by M. Tony Petitjean, of Geneva,
Switzerland, Chemist.
I, EUGENE RASCOL, of 4, Brydges Street, Covent Garden, in the County
of Middlesex, do hereby declare the nature of the Invention for "IMPROVE-
MENTS IN THE MANUFACTURE OF GLASS," to be as follows:-
This Invention consists in using the glass cylinder (in French manchon) such
as has been made by the glass blower for making panes of glass, but without
cracking it all along as it is the usual practice, then to expose to a red heat
the cylinder hanging upon a rule as straight as possible and placed in a
perfectly horizontal position, another rule of the same thickness as the former
being placed freely on the inside bottom of the cylinder parallel to the upper
These rules ought not to be of a completely metallic nature, for
whatever the metal chosen might be the heat would not fail to alter their
straightness after a short time and besides they would be too heavy for large
pieces. The cylinder (or manchon) being so hung on one of those rules and
bearing the other at its inside and lower part is exposed to the heat, which
softens the glass. The lower rule goes down by its own weight, thus changing
the cylinder into two plane surfaces ending at the top and the bottom, and at the
bottom by a little curve caused by the rule. The piece being then allowed to
slowly cool down the two plane surfaces are severed from each other with a
glazier's diamond, each forming a pane of glass perfectly plane, and having pre-
served the fine polished state to be seen in crown glass. After this operation

page_text: the glass cylinder is put into a spreading furnace where it soon expands and
forms two sheets of glass the breadth of which is about one and a half times
the diameter of the cylinder employed. It might be then objected against
the spreading process that only narrow pieces can be obtained by it, but the
glass cylinder can be regularly and indefinitely elongated at the expense of
its thickness according to the length of time it is exposed in the spreading
oven. Then by limiting the time of the operation to the required size, any
size can be given to the breadth of the plates. The glass blower. has only to
blow the glass thicker than in the ordinary process. The spreading furnace
is composed of three principal parts, the spreading one always divided in even
numbers of similar compartments, four, six, or eight as may be required, each
of them forms by itself a spreading oven in the front of which is a working
orifice. The upper part in immediate connection with the spreading ovens is
a transversal gallery to receive plates of glass when spread, and destined to
work them in the manner required. The other part consists of two longi-
tudinal galleries one opposite the other for the cooling and annealing of the
glass. All the motions required for the working of the process are performed
by means of a peculiar and appropriate mechanism. The kiln is kept
continually working.
The construction of masonry and some mechanical arrangements insure the
constant parallelism of the chains when at work. As the rules used for the
stretching of the manchons are an important part of the Invention, I will
describe their preparation and composition. These rules consist of bands of
carbon prepared either according to the mode of manufacture of blacklead
pencils, or according to the mode indicated for the preparation of the carbon
cylinder in the Bunsen pile. However instead of coke, anthracite in fine
powder is used. After having submitted to a first baking (burning) the
mixture of anthracite and smith's coal is dipped in a solution of vegetable salt
of iron and copper instead of a syrupy solution, and it is afterwards submitted
to a second baking before a strong fire. Mineral carbon extracted from
the gas retorts may also be used, and which very properly attains the end
contemplated.