Freeland tribune. (Freeland, Pa.) 1888-1921, 1890-02-13

last three centuries, Just as painting has
done. The Venetian artists in glass have
left no successors. Beautiful effects are
still obtainable in stained-glass windows
and Ornamental goblets, but collection
OF sixteenth century relics is not indica-
tive of modern progress, or of any COM
parison which can be said to be other
than odous.
Entering glass factory, the first object
which attracts attention is the great CEN
tral furnaces in which the glass is melt
ed The most unobservaht person will
have noticed that ordinary glass presents
itself in three aspects-brown, green, and
stainless white or flint glass. The former
tints are due to the presence of iron-oxide
in the sand, which is one of the prnci-
pal ingredients. When colorless glass is
desired the iron has to be eliminated, or
the color masked by suitable means, and
it is noteworthy fact that proportion
of iron in the sand too small to be indi-
Gated by the most delicate assay will i'm
part distinct hue to glass. Different
metallic oxides impart different hues;
thus tin or arsenic will render the product
white and Opaque, gold will give ruby
red, copper in the form of black oxide
with little iron ore will yield an en-
erald- green product; cobalt oxide blue,
manganese a purple oxide of uranium a
yellow, and SO on.
1t follows that where colorless glass is
desired the greatest care has to be taken
to insure the use of sand in which the
metallic oxides referred to are distin-
guished by their absence.
The furnace takes up quite large part
of the room in glass factory and is cir
cular in form, to allow the operators to
approach the pots from all sides. The
a11t will riy Of
the arrangement of the melting pots on
the siege or true floor of the furnace. AS
these melting-pots are of large size (some
are fifty five inches in diameter) and have
to Withstand continuously heat which
will easily melt iron or steel, it follows
that they have to be made of we'll knead-
ed, tempered and annealed tire-clay.
There is glorious uncertainty about the
life of melting pot. 1t may give way
and break up in eight hours, or it may
last for months. In any case the sides
wear through and get thin in the lapse of
time from the absorption of the clay
into the vitrifed molten mass within.
just so long as good pot can be patched
pot has to be removed, no matter un-
der what circumstances, it means
a hot, hard days work for all hands. The
first thing is to dislodge the broken frag-
ments of the pot, or the whole affair
bodily if not broken, by battering- ram
blows directed with gigantic crowbar
into the interior of furnace heated like
unto that into which Shadrach, Meshech,
and Abednego were cast in the days of
old. When the work is completed, the
new pot already annealed and heated to
whiteness, has to be placed in position,
and as the pot and contents may weigh
many hundred pounds, the ordeal is
necessarily severe one. Burns and
blisters are every day occurrences in
glass factory, but the visitor soon learns
one lesson. If he wishes to avoid burns
and blows he will not seek TO get out of
the way of the mon. He will act most
wisely in recognizing that they have an
independent intelligence. The man who
keeps cool in crossing street will be