The Denison review. [volume] (Denison, Iowa) 1867-current, 1902-07-22
GLASS FOR WINDOWS
THE METHOD AND THE MATERIALS
OF ITS MANUFACTURE.

an Ordinary House to Kill n Regi-
ment of Men-Frocess of the Tank
house and the 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 an ordinary home con-
tain enough of this poison to kill reg
iment of men. The popular supposition
! that glass is made of sand is a correct
one, but q quantity Of other articles en-
tiers into its composition.
Window glass factories are divided
into two departments, a farmhouse and
a pothouse. The process of glassmaS-
ing in one of these departments is prac
tically the same as in the other. In the
tanllhouse the glass is all melted In i'm
mense tanks which will hold thou
sands of tons. In the pothouse 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 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 manner similar to that of
;,, 1i,.ti no
cake comes q 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
J 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 long steel blow
pipe 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 a box of
: sawdust and then passed on to the
blower, who heats it again until it be-
J comes like taffy. The blower swings
the ball over Il 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
feet across. 1t then passes to ''snap-
, per- who takes it to rack and breaks
: the roller loose from the b]owpipe.
] The snapper gathers a small lump
of melted glass on the end of rod
and deNterously runs 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 seconds,
when they are removed, leaving a mar
row zone Of almost redhot glass
around the rollers at each end. Then
: taking tool that resembles a soldering
! iron, the snapper rubs it for moment
on his forehead, and when the point OF
n 1t is moistened with perspiration he
e runs the iron around the rollers at the
Il heated spot, The glass cracks ant
= separates as clearly as if cut with
diamond. the blowpipe is removed, ant
the closed cylinder has become role
g and is then ready to go to the fiat
e tener.
II The fattener works in another par
n of the building, where are located tn
re fiattening ovens. These ovens are heat
n. ed to temperature sufficient to softer
IL the glass SO that it may be rolled GU
), into sheets. A series of tireclay table
placed in circle like the spokes of
wheel reyo,ye in the ovens, and O
% these tables the rollers are fattenet
n They are placed inside, allowed to be
lh come hot, and then cold iron Is ru
w along the inside from end to end. Th
IA contact Of the iron cuts the glas!
- which is then Strengthened out upo
:. the table.
The 11attener has a number of billet
Of green wood attached to long iro
ad handles, and with these billetS, who
er are shaped in such a manner as to
be the work expected OF them, he irons
is the softencd sheet Of glass until il
ht perfectly fat and smooth. The table
sc inside tho oven reyolve, the fiattene
sheet is carried away. and another rol
er is brought into position before tt
lattener. AS the fiatlened sheets co
ne they are lifted to place on ioI
i'll travelling rack, on which they are |
ad stages removed from the ovens, bei1
allowed to cool as they go. This is dol
in order that the glass may not
shattered by too quick an exposure
al: the air.
to- When the sheets are taken from Il
an hattening ovens. they are covered wi
is Il greasy, dirty looking coat of cher
no icals soda, potash silicntes Of the d
- ferent salts, etc.-Which must be
- moved, and for this purpose the rou;
80 sheets are placed In an acid bath COZ
va posed Of hydrochioric and sulphur
re. acids more or less diluted. After the
he immersion III this bath the sheets q
at taken to the cutting room, where wol
s men cut them into sizes and ma
them ready for the packers. Hardly
scrap of the glass except the rou
DOL edges is wasted. In fact none is wa