The herald-advance. (Milbank, S.D.) 1890-1922, 1902-11-21
GLASS FOR WINDOWS
THE METHOD AND THE MATERIALS
OF ITS MANUFACTURE.

-" AAOoSG AAAA1 - NG6ls
ment OF Men-Process of the Tank
house and thu Pothouse.
People who have glass windows In
their homes do not know that the glass
contains enough arsenic to make it a
deadly poison. Glassmakers say that
the windows of a IN ordinary home con
tain enough Of this poison to kill a reg
iment of men. The popular supposition
that glass is made Of sand is a correct
one, but a quantity of other articles en-
ters into its composition.
Window glass factories are divided
a pothouse. The process of glassmak-
Ing In one Of these departments Is prac-
tically the same as in the other. In the
tankhouse the glass is all melted in inn
mense tanks which will hold thou.
sands Of tons. In the pothouse the
glass is made in pots.
After the fires are lighted and a tank
Is heated the glass mixture is shoveled
In. 1t includes glass left over from the
former season, glass refuse, sand and
salt cake. Arsenic is not used In the
tankhouse for the reason that the heat
Is so intense that the drug is volatilized
and escapes into the air without enter
ing the mixture. AS one mixture melts
and flows to one end of a tank fresh
supplies are shoveled in at the other
end.
The molten mass seethes and
works" in a manner similar to that of
a mash in a distillery. From the salt
cake m a salt water that has to be
separated from the mass. and the east
est way to remove 1t is to burn it out.
This is done by throwing stove wood
into the tank on top of the molten
glass. The water Is converted into
steam. which is destroyed by the in
tense heat from the glass. The melted
glass is then skinned by an automatic
skinner. and it is ready for the gath.
erer.
A gatherer thrusts a long steel blow
pipe into cne of the rings at the lower
end Of the tank. He twists and turns
it until a small ball of glass gathers on
the end. This ball is partially cooled,
polished by being turned in a box of
sawdust and then passed on to the
blower. who heats it again until it be-
comes like taffy. The blower swings
the ball over a pit that is twelve feet
deep and rapidly blows it into an elon-
gated pear shape. When a blower is
through. the melted glass becomes a
perfect cylinder about 5 feet long and
2 feet across. 1t then passes to a snap
per-" who takes it to a rack and breaks
the roller loose from the blowpipe.
The snapper gathers a small lump
Of melted glass on the end of a rod
and dexterOusly runs a narrow ribbon
Of the stuff around the ends Of the
roller, both at the blowpipe end and
melted glass cool in a few seconds.
when they are removed, leaving a mar
row M of almost redhot glass
around the rollers at each end. Then,
taking a tool that resembles a soldering
iron, the snapper rubs it for a moment
on his forehead. md when the point OF
it is moistened with perspiration he
runs the iron around the rollers at the
heated spot. The glass cracks and
separates as clearly as If cut with a
diamond. the blowpipe is removed, and
the closed cylinder has become a roller
and is then ready TO go to the fat
tener.
The fiattener works In another part
Of the building, where are located the
flattening ovens. These ovens are heat
ed to a temperature sufficient to soften
the glass so that 1t may be rolled ont
into sheets. A series OF ireclay tables
placed in o circle like the spokes of a
wheel revUlve In the overs. and on
these tables the rollers are lattened.
They are placed inside. allowed to be-
come hot. and then a cold iron Is run
along the inside from end to end. The
contact Of the iron cuts the glass.
which Ii then Strengthened out upon
thu table.
The dattener has a number of billets
Of green wood attached to long iron
handles. and with these billets. which
are shaped In such a as to do
the work expected Of them. he irons"
the softened sheet OF glass until it is
perfectly Hat md smooth. The tables
~ SAN WA lCNOtVCs LIE uAllCuCu
sheet Is carried away. and another roll
er Is brought into position before the
flattener. As the flattened sheets cool
they are lifted to a place on a long
travelling rack, on which they are by
stages removed from the ovens. being
allowed to cool as they go. This is done
In order that the glass may not be
shattered by too quick an exposure to
the ulr.
When the sheets are token from the
~fsttening ovens. they are covered with
= greasy. dirty looking coat Of chem
icals-soda. potash. silicates Of the diff
ferent salts, etc.-which must be re-
moved, and for this purpose the rough
sheets are placed In an acid bath COM
posed Of ~hydrochl0ric and sulphuric
acids more or less diluted. After their
immersion In this bath the sheets are
taken to the cutting room, where work
II 1880 1900 t-k~ 49,