The weekly messenger. [volume] (St. Martinsville [i.e. St. Martinville] La.) 1886-1948, 1888-11-03
GLASS MANUFACTURE
Processes for Producing This
Fragile Substance.
The Well-Preserved Secrets of
the ClaSSmaker'S Art.

The process of manufacturing glass is
exceedingly interesting; but it is also
elaborate and not free from compllca-
tons.
So intricate is the work in some of its
departments that one IS puzzled at the
proficiency in the art in ancient times.
The composition Of which glass is made,
not to mention the fusing and finishing,
implies large amount of chemical
knowledge. Generally 1t may be de-
scribed as consisting of certain num-
Der of silicates such as soda, potash,
lime, baryta, magnesia, alumina and
lead, the coloring matter being obtained
from iron, maynesia, cobalt, uranium,
copper or gold The composition, of
course, is conditioned or qualified by
the kind of glass which is wanted. The
test glass is that which contains the
minimum of uncombined silica. Bohe-
milan glass of the harder kind contains
the silicates OF potash and lime in pre-
domino ant proportions; of the softer
kind it contains, in addition, a notable
quantity of the silicate of alumina.
Soda and lime predominate in French
plate. Potash and lead are the princi.
pal silicates IN the ordinary flint, or
white glass. The lead gives density,
softness, fusibility and brilliancy. The
exact proportions, in different cases of
the different Ingredients, belong to the
secrets of the glassmaker's art.
The process of manufacturing varies
with the different kinds of glass. The
first step in the process, however, is the
same with all glass. The first requisite
is the melting pot, the making of which
is an art by itself. 1t is made of the
present kind of clay and consists pretty
nearly of equal proportions of silicon
and alumina. The mass, consisting also
often of pieces of old pots, is worked
up with water and then laid aside for
luIee vi 4OuI luOIiu-. IL ID dItcE tAtI
time made into pots-the work being
OF the most particular and laborious
kind-covcred at top and bottom, with
an opening at the side. When thor .
ou,hly dried and hardened in the fur
mace, the pots axe filed with prepared
materia., called frit, mixed with a small
quantity of culiet, or broken glass.
After some ten or twelve hours, the
heat of the furnace having been brought
to the highest point, the pots
are skinned and tho melted material
is ready for what Is called the journey.
During the melting process the color.
ing is done by means OF various metallic
oxides. What is called flashed glass i:
produced by another and different pro.
cess. 1t is only specifically colored'
Pot metal, when colored, is coloret
throughout. When tho material i:
thoroughly melted and SKINNED and
made read for the journey the work o
the blower or molder begins. Bottle
and window gla,s-crown or sheet--arC
made by the blow pipe. What i
known as plate glass and optical glass i;
cast; AMI the glass used for heavy do
nestle utensils is the result OF com
bined process of blowing and casting
The blow-pipc in glass making play
precisely the same part which Is per
formed by the pottcr's wheel in tn
manufacture of eartheaware. |
is an iron pipe smaller a
the mouth end than at the other
In the manufacture OF flint glass tn
pine is heated almost to redness, thel
inserted into the pot Of fused glass
which adhc-es to it. BY turning l
round the workman gets as much meta
as he requires. He then distends tn
glass by blowing through the pipe ant
the glass being put into a mold he con
tinues to blow until the desired shap
is produced. In this way kettles ar
made. and also almost all articles 10
domestic use. Window glass is blow
into the form of cylinder. The end
of the cylinder are, after coolin:
process, cut off. The cylinder is the
slit by diamond from end to end, an
being again heated, it il with mucl
care and labor gradually fiattencd out
Plate glass is made in different man