Lamoille newsdealer. [volume] (Hyde Park, Vt.) 1860-1877, 1869-04-06
M i 5 G q l l u N "
HOW COMMON WINDOW GLASS is MADE.
BY ]. T. TRowBRIDGE.

visit Pittsburg, in Pennsylvania, you must
go into the window-gass factories there /;
you will find them very curious. Their
furnace, in the first place, is built in the
ancient style; it has no chimney, and the
smoke from the bitumenous coal they
burn, pours out into cloud into the
room. There are openings in the roof for
it to escape through, and a continual
draug hit Of air from the doors carries it
upwards, SO that it is not so bad for the
workmen as one would think. Besides
they do not begin to blow until the smoke
is all burnt off.
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 regu-
larity of file of soldiers exercising.
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 five men begin to blow and swing all
together Each blows a great globe of
glass, which is stretched out gradually by
the swinging motion into cylinder, or
roller, as it is called, five feet long. Then
the five rollers are swung up towards 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 blowing pipes to
support them while the rollers are being
reheated in the necks of the pots. The
blowes blow in the neck 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 that at
last the air, forced in and expanded by
the heat bursts it outwards. The glass
is then cylinder, open at one end. 1t
is whirled in the heat until the edges be-
come true, then brought away,-the five
iron supports dropping to the ground with
a simultaneous clang. The cylinders are
laid on tables, where the imperfect spheri-
cal end about the blowing-pipe is cracked
off from the rest by stripe of melted
glass drawn around it. The cylinder is
then cracked from end to end on one side
by means Of a rcd-hot iron passed through
it.
In an adjoining building is what is call
ed the fattening oven. The cylinders
brought there are lifted on the end of a
lever, passed in through circular open
ing just large enough to admit them, and
laid on hattening stones on the oven bot
tom is circular, and it revolves horizont-
ally. AS the glass softens, it separates at
the crack, and lays itself f,lown gently and
gradually on the stone. The long cylin-
der is then flat 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
workman sweeps the stone for it, third
workman smooths it down with a 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-part-
ly cooled by this time-upon a carriage
in the oven. This he does by means OF a
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 annealing oven beyond
The opposite end of the annealing oven
opens into the cutting-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 SCHOOL
boy rules his slate. His ruler is wood
en- rod, five feet long, and his pencil-point
is diamond. Every stroke is cut Not
that he cuts the glass quite apart; indeed
he seems scarcely to make scratch. Yet
that scratch has the effect of cracking the
glass quite through, so that it breaks
clean off at the slightest pressure. In
this way the sheets are cut up into panes
of the requisite SIZE"
IL should think the diamonds would
wear out" said Lawrence.
81 remember" said the gafer, zone
workman told me that single diamond
would last him two or three years. 1t
has fifteen or sixteen different edges, and
when one edge is worn out he uses anoth-
er. 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 thom
for jewels to be put into watches. .'--Ou,
Young Rolts,