Evening star., 1902-03-17
MAKING WINDOW GLASS
VARIOUS STEPS IN AN INTEREST
ING PROCESS DESCRIBED.
Large Amount Arsenic in the Trans.
parent and Brittle SUFFICIENT
Gals and Sand.

From the Indianapolis News.
People who have glass windows in their
homes do not know that the glass contains
enough arsenic to make it deadly poison.
Glassmakers say that the windows Of an
ordinary home contain enough Of this
poison to kill a regiment of men. The
popular suppOsitiOn that glass is made of
sand Is correct one. but a quantity of
other articles enters into it's composition.
Window glass factories are divided into
two departmental tankhouse and a pot
house. The process of glassmaking In one
OF these departments is practically the
same as in the other. In the tankhouse the
glass is all melted in immense tanks which
will hold thousands of tons. In the pot
house the glass Is made in pots After the
fires are lighted and 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 Volat1llZed and escapes into the air with
out entering the mixture AS one mixture
melts and flows to one end of tank, fresh
supplies are shOveled in at the other end
The seething Mass.
The molten mass seethes and works in
manner similar to that Of a mash in
distillery. From the salt cakes comes a salt
water that has to be separated from the
mass, and the easiest way to remove it 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 intense
heat from the glass. The melted glass is
then skinned by an automatic SKINNER
and 1t Is ready for the gatherer A gath
erer thrusts long steel biowp- re into one
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 box of sawdust and then passed on to
the ane nioWer WEI, who VINO heats 1t again until it be-
ball over pit that is twelve feet deep and
rapidly blows 1t into an elongated pear
shape When. blower is through the
about Ave feet long and two feet across.
1t then passes to snapper" who takes il
to rack and breaks the roller loose from
the blowpipe.
Ribbons of Glass.
The snapper gathers a small lump Of
melted glass on the end of rod and dex-
terously runs a narrow ribbon Of the stuff
around the ends Of the roller both at the
blowpipe end and the closed end. The little
ribbons of melted glass cool in a few Sec
onds when they are removed, leaving a
narrow zone of almost red-hot glass around
the rollers at each end. Then, taking a tool
that resembles a soldering iron, the snap
per rubs 1t for moment on his forehead,
and when the point of 1t is moistened with
perspiration he runs the iron around the
rollers at the heated spot. The glass cracks
and separates as cleanly as IL cut with a
diamond. the blowpipe is removed and the
closed cylinder has become a riller-a sheet
closed cylinder has become a roller-a sheet
music, only In a continuous roll, without
edges The roller is then ready to go to
the fattene&
The fiattener works in another part of
the building. where are located the fat
a temperature sufficient to soften the glass
SO that 1t may be rolled out into sheets.
series of fire-clay tables. placed in a
circle. like the spokes of wheel. revolve
In the ovens. and on these tables the roll