The weekly messenger. [volume] (St. Martinsville [i.e. St. Martinville] La.) 1886-1948, 1890-03-08
A GLASS FACTOR
How the Glass is Melted, Rolled
and Blown.
Liability of the Workmen to
Burns and BliSterS.

Entering glass factory, the first OBJ.
ject which attracts attention is the
great central furnaces in which the
glass is melted. The most uno bservant
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 principal ingredi-
ents. When colorless glass is desired
the iron has to be eliminated, or the
color masked by suitable means, and it
is a noteworthy fact that a proportion
Of iron in the sand too small to be in
dicated by the most delicate assay will
impart distinct hue to glass. Differ
ent metallic oxides impart different
hues; thus tin or arsenic will render
the product white and Opaque; gold
will give a ruby red; copper, in the
form of black oxide with a little iron
ore, will yield an emerald green prod
uct; cobalt oxide blue; manganese q
purple; oxide of uranium yellow, and
so on.
1t follows that where colorless glass is
desired the greatest care has to be
taken to insure tho use of sand in
which the metallic oxides referred to
are distinguished by their absence.
The furnace takes up quito a large
part of the room in glass factory, and
is circular in form, to enable the opera
tors to approach the pots from all sides.
As these melting pots are of large size
(some are 55 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 kneaded, tempered and annealed
re-clay. There is a glorious uncer-
tainty 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 alb
sorption of the clay into the vitrifed
molten mass within. Just so long as a
good pot can be patched up and forth
fed it is kept in use, but when a pot
has tc be removed, no matter under
what circumstances, it means a hot,
hard days work for all hands. The
first thing is to dislodge the broken
fragments of the pot, or the whole affair
bodily if not broken, by battering- ram
blows directed with gigantic crowbar
into the interior of O furnace heated
like unto that into which Shadrach,
Meshech anO Abcdnego were cas-. in the
days of OLD. When the work Is COM
pleted the new pot, already annealel
and heated to whitene.s. 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.
1t is a busy scene, this interior of a
glass factory in full blast. About a
hundred hands, men and boys in nearly
equal proportions, are employed. First
an operator sticks the end of a long
iron tube into glowing white hole
and draws the instrument forth with
glistening gelatinous looking mass at
the end. He rolls this mass actively
Tor few moments on q fiat slab called
a"marver-" The marver is placed in
aslightly inclined position on wooden
slab, and the rolling of the glass on
the surface, easy as it looks, is quite an
art.
While the glass is still in the soft,
pasty condition, the operator blows it
slightly and guides the lump into the
interior of a mold closed by treade,
blowing it all the time. The trans
formation is almost instantaneous, and
when the pressure on the treadle is re-
leased the tube is withdrawn, with a
full blown bottle at the end Of it.
as already remarked, this bottle mould
Is an American invention, aud the saw
ing in the case of cheap goods is very