Delaware gazette. [volume] (Delaware, Ohio) 1855-1886, 1869-05-07
HOW COMMON WINDOW-GLASS
Is MADE.
BY J. T. TRowBRIDeB.

There is anotherprOcess.' y continued
/ the gatfer, "by which our common win
/ dow-glass is made. By the way, if ev-
or you visit Pittsburg. in Pennsylya-
/ MIA, you must go into the window-gla
| factories there you will find them
very curious. Their furnace inthe first
| place, is built in the ancient style: il
| has no chimney, and the smoke from
| the bltuminous coal they burn, pOurs
out in a cloud into the room. There
are openings in the roof for il to escape
| through, and~a continual drought of
air from the doors carries Il upward, so
| that it is not 50 bad for the work men
as one would think. Besides, they do
not begin to blow until the smoke is all
burnt OF.
''There are i've pots on each side Of
the furnace and you VIII see Gve men
IN row, blowing all at once, with the
regularity of file OF soldiers exereis-
ing. Each gathers thirty or forty
pounds Of metal on his pipe which is
very long and strong They stand on
platforms, to get room to swing the
glass, as they blow it. The i've men
begin to blow and swing all together.
Each blows great globe ofglass, which
is stretched out gradually by the swing
ing motion into cylinder, or roller, as
it Is called, five feet long. Then the
five rollers are swung up towards the
furnace holes, and i've other soldiers
spring forward with their guns,-and
which in this case are iron bars, that
they set upright under the five blow
ing pipes to support them while the
the rollers are being reheated in the
necks 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 6he air from rushing
out again in the meanwhile the end
of the roller softened, so that at Last
the air, forced in and expanded by the
heat, bursts it outWards. The glass Is
then cylinder, open at one end. It is
Whirled in the heat until the edges be-
come true, then brought away,-the
five iron supports dropping to the
ground with Simultaneous
clang. The eylin ders are laid on tables,
where the imperfect spherical end
about the blowing-pipe is cracked Of
from the rest by q stripe OF melted
glass drawn around it. The cylinder is
then cracked from end to end on one
side by means of a red-hot iron passed
through it.
called the hsttening oven. The eylin-
ders brought there are lifted on the end
of q lever, passed in through circu-
lar opening just large enough to admit
them, and laid on 6attening stones on
the oven bottom, with the crack upper
most. The oven bottom is circular. and
it reVolves horizontally. AS the glass
softens, 1t separates at the crack, and
lays itself down gently 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 |
another a workman sweeps the stone
for it, q third workman SmOOths itdoWn
with block as it comes round to him,
and fourth, at the last opening, which
is close to the one at which it was put
in, lifts the sheet-partly cooled by this /
time-upOn a carriage in the oven. This
he does by means of q lever furnished
with sharp, broad blades at the end,
which he works in under the glass.
When the carriage is full, it is run
through an anuealing oven beyond.
''The opposite end of the annealing
oven opens into the cuttiDg-room.
There the carriages are pushed along
central track, and unlOaded at the
stalls of the cutters. The cutter has a
table before him, with measurements
on its edges. He lifts one of the sheets,
lays it on the table, and commences
ruling it faster than a school-boy rules
his slate. His ruler is a wooden rod,
five feet long, and his pencil-poiBt is a
diamond. Every stroke is cut. Not
that he cuts the glass quite apart in
deed, he seems scarcely to make q
scratch. Yet that scratch has the effect |
of cracking the glass quite through, 80
that it breaks clean off at the slightest |
pressue. In this way the sheets are cut
up into panes of the requisite size"
'fI should think the diamonds would |
wear out, J" said Lawrence.
''I remember" I" replied the gaffer, "one |
workman told me that single diamond |
would last him two or three years. It |
has fifteen or sixteen different edges, |
and when oLe edge is worn out he used |
another. South American diamonds, |
such as he used, 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 into |
watches" ."-OUR YOUNG FOLKS.