Spirit of Jefferson. [volume] (Charles Town, Va. [W. Va.]) 1844-1948, 1870-09-13
How Common Window Glass is Made.


If you ever visit Pittsburg in Pennsylvania,
you must 90 into the window-glass factories
there you will find them very curious. Their
furnace, in the first place, is built in the
ancient style; it has no chimney, aud the
smoke from the bituminous coal they burn,
pours out in cloud into the room. There are
openings in the roof for it to escape through,
and a continual draught of air from the doors
carries it upward, so that it is rot so bad for
the workmen as one would think Besides.
they do nA begin to blow until the smoke is
all burnt off
There are FIVE pots on each side of the fur
mace and YOU will see five men in row,
blowing all at once, with the regularity of a
file of soldiers exercising. Each gathers so
or pounds of metal on his pipe which is very
long and strong They stand on platforms to
get room to swing the glass, they blow it.
The Ave men begin to blow and swing all
together Each blows great globe of glass.
which is stretched out gradually by the swing
ing motion into a cylinder or roller. ns it is
called, five feet long Then the FIVE rollers
are SWING up toward the furnace holes, and
6ve other soldiers spring forward with their
guns,-whch in this case are iron bars that
they set up upright under the five blowing
pipes to support them while 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 the air from rushing out
again in the meanwhile the end ofthc roller
is sOftGned. so that at last the air. forced in
and expended by the heat, bursts it outward.
The glass is then a cylinder. open at one end.
1t whirled in the heat until the edges become
true then brought away,-the five iron sup
ports dropping to the ground with simulta-
neOus clang. The cylinders are laid on tables,
where the imperfect spherical end about the
blowinS-pipe is cracked off from the rest by
strip 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.
In an adjoining building is what is called
the fattening oven. TIE cylinders brought
there are lifted on the end Of a lever, PASSED
in through a circular opening Just large enough
to admit them. and laid on flatteniug stones
on.the oven bottom. with the crack uppermOst.
The oven bottom is circular. and ii revolves
horizontally. As the glass softens. it sepa-
rates at the crack, and lays itself down gently
and gradually on the stone The long cylin-
der is then fat sheet. three feet wide and
nearly fre feet in length. There are four
openings around the sides Of the oven; Mt one
the glass is put il. through another a work.
man sweeps the stone for it. third workman
smoOths it down with Il block ns it comes
round to him. and fourth. at the last open
ing. which is clnse to the one at which it was
put in, lifts the shect-partly cooled by this
tiuG-upon carriage in the oven. This he
does by means of 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 anneaing oven beyond
The opposite end OF the annraling oven
opens into the cutting-room. There the car
riages are pushed along a central track, and
unloaded a. the stalls of the cutters The
cutter has a table before him. with measure
marks on its edges. He lifts one Of the sheets.
lays it nm table. and commences ruling it
faster than school-hoy rules his slate. His
ruler is n wooden rod. five fact long, and his
penci)roint is diamond. Every stroke ia a
cut. Not that it cuts the glass quite apart.
indeed. he seems scarcely to make a scratch.
Yet that scratch has the effect of cracking
the glass quite through 50 that it breaks clean
off at 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 Is or 16 different edgess. and
/ when o=e edge is worn out he uses another.
/ South America Diamonds. such rs he used,
/ cost he told me. from six 70 Thirty dollars
/ each ard when they are worn out for his
| purpose. he sells them for jewels to be put in
watches.-J. T. TroasLridye, IN Our Yong
/ FoLhS.