The Tiffin tribune. (Tiffin, Ohio) 1868-1887, 1872-03-28
How Common window Glass is Made.


/ If ever you visit Pittsburg, in Penn
sylvania, you must 20 into the win
dow glass factories there; you will find
them very curious. Their furnace
IN the first place, is built in the an.
eient style; il has no chimney, and
the smoke from the bituninOus eoal
they burn pOurs out in q cloud into
the room There are openings in the
roof for it TO escape through, and 8
continual draught from the doors
/ carries it upward, so that il is not 90
/ bad for the wOrkmen as one would
think. Besides, they do not begin TO
| blow until the smoke is all burnt of.
There are five pots on each side OF
[ the furnace; and you will see five
men in a row, blowing all at once, with
the regularity of file Of soldiers exer-
cising. Each gathers 80 or 40 pounds
of metal on his pipe, which is very
long and strong. They stand on plat
forms to get room to swing the glass
as they blow it. The five men begin
to blow and swing all together. Each
blows q great globe Of glass, which Is
stretched gradually by the swinging
motion into a cylinder or roller, as il
is called, five feet long. Then the
five rollers are swung up toward the
furnace holes, and five other soldiers
spring forward with their guns
which in this case are iron bars, that
they set upright under the five blow
ing pipes to support them while the
rollers are being heated in the neeks
of the pots. The blowers blow in the
necks Of the pipes with all their
might, then clap their thumbs over
the holes to prevent the air from
rushing out again; in the meanwhile
the end Of the roller Is sOftened, so at
last the air, forced in and expanded
by the heat bursts it outward. The
glass is then a cylinder, open at one
end. 1t is whirlied in the heat until
the edges become true, then brought
away-thef five iron supports dropping
to the ground with a simultaneous
clang. The cylinders were laid on Ia
bles, where the imperfect spherical
end about the blowing pipe is crack
ed off from the rest by a strip Of melt
ed glass around it. The cylinder is
then cracked from end TO end on one
side by means Ofa red hot iron passed
through it.
In the adjoining building is what is
called the fiattening oven. The cyl
inders brought there are lifted on the
end Of lever, passed in through a
circular opening just large enough to
admit them, and laid on fiattening
stones on the oven bottom, with the
crack uppermOst. The oven bottom
is circular, and it revolves horizontal
ly. AS the glass softens it separates
at the crack, and lays itself down gem
tly and gradually on the stone. The
long cylinder is then a fiat sheet, three
feet wide and nearly five feet in
length. There are four openings
around the sides of the oven at one
the glass is put in, through an
other workman sweeps the stone for
it, third workman smooths it down
with block as it comes round to him
and a fourth, at the last opening, which
is close to the one at which it is put
in, lifts the sheet-partly cooled by
this time-upOn carriage in the oven.
This he does by means of lever furn-
ished with sharp broad blades at the
end, which he works in under the
glass. When the carriage is full it is
run through an annealing oven be-
yOnd.
The opposite end of the anneaIing
oven opens into the cutting room.
There the carriages are pushed along
a central track, and unloaded at the
stalls of the cutters. The cutter has q
table before him with measure marks
on its edges. He lifts one of the
sheets, lays it on a table, and com.
mences ruling it faster than a school
boy rules his slate. His ruler is 6
wooden rod, five feet long and his
pencil point is diamond. Every stroke
is a cut. Not that he cuts the glas:
quite apart; indeed he seems scarcely
to make a scratch. Yet that scratch
has the effect Ofcutting the glass quite
through, so that it breaks clean off al
the slightest pressure. In this way
the sheets are cut up into panes of the
requisite size.
remember, one workman told me
! that a single diamond would last him
two or three years. 1t has fifteen OF
sixteen different edges, and when one
was worn out he used another. South
American diamonds, such as he uses,
cost, he told me, from six to thirty
dollars each; and when they are worn
out for his purpose, he sells them for
jewels to be put in watehes.-J T.
IFOlDbrid0e.