The Middlebury register. [volume] (Middlebury, Vt.) 1850-1882, 1876-10-15
How Glass is Made.

DELIGHTFUL WORK FOR SUMMER WEATHER
RED HOT GLASS STIRRED WITH WHITE
HOT LADLEs-How THE PRETTY GLASS
ORNAMENTS ARE MADE.
The Centennial is the fret international
exhibition to have a complete glass man.
ufactory in full operation. In this coun.
try Pennsylvania takes the lead in the
manufacture Of glass aud OF articles made
from it. There is, perhaps, DO industry
requiring as much skill as that ofmaking
glassware, for the reason that the most
elaborate, as well as the meanest, work
of this kind must be executed with very
few tools oI the simplest pattern, and DE-.
pends almost solely for its excellence upon
a dexterous muscle aud an educated eye.
Just west Of the saw mill annex Of Ma.
cbirery Hall, is the factory in question.
The building is one hundred feet long and
sixty feet wide, having an annex forty
feet square on the southern sido. La pro.
portion to it's size, no Centennial building
has been more visited than this, not with.
standing the addition of the heat from the
furnaces TO that from old Sol. In tenn.
perate weather, however, tho place is not
uncomfortably hot, except near the far.
mace. A "blower.. forces a current of air
through an iron pipe, having openings at
which flexible tubes arc attached. The
workmen are eased by having them di.
rected toward their faces. The melting
furnace is large conical brick structure,
verging into chimney nearly eighty feet
high. The draft is not forced, but comes
from an excavation under the floor, com.
municating with the open air on both sides
Of the building. In tho furnace are elev.
en- melting pots. with an aggregate capac.
ity OF about sixty gallons, each being
against an "eye" or opening in the wall.
The fuel used is bituminous coal, and the
contents Of the pots arc kept at a white
heat.
Only Eve or six of the pots are charged
at tino, tho others being meanwhile
used for working. The principal material
in the uncolored glass is pure white sand,
uniform and finer than beach sand, 1t is
said to be calcined flint, but that is un.
certain. To act as Aux. an alkali, such
as soda, soda ash, litharge or lime, is
combined with the silica. in proportions
varied according to the quality of glass
required. The glass is colorcd by tho
addition Of metals or metallic oxides, q
ruby color being produced by tho addition
of gold a green by the oxides of iron
and copper a blue by cobalt, and an
amber by the oxides of gold. The mix.
ture is sealed in the pots by clay, and is
subjected to an intense heat for forty.
eight hours, after which ii is used. while
the other set of pots is charged in like
manner, the fire being under aid around
them. BY some visitors the operators, Of
whom there are about sixty. are regarded
as kind of jugglers, so curious and near
the incredible are the results of many of
their operations. The most of their ge.
ometry is their eye and muscle, rules,
squares and such things being totally
disregarded. A gatherer. generally q
boy. dips the end Of an iron tube, four
feet long, into the pot, collects on it q
bulb of the melted glass, and hands the
tube to the blower, who at first must swell
his cheeks to the greatest extent, to start
the expansion. after which tho imitation
of the growing bulb is easily effected.
If glass egg is desired be stops blowing
when the bulb is as largo as an egg; puts
the tube on bench-the bulb being Of
tho edge-rolls it, and while doing So
holds the shesrs-tool having large tri'
angular arms-near the junction of the
bulb with the tube. By gentle pressure
he gradually lesseRs the quantity Of glass
forming the union, and this process also
shapes the small end Of the egg. The lat
ter is then broken of, cooled, and has III
rough end smoothed on a cutting lathe
In making goblet the blower alternately y
initiates the bulb little, and rolls II on /
smooth iron plate. thus keeping Il some
what cylindrical.
When 1t is large enough-stil beini
hot--he ticks on the end which is TO b,
the bottom Of it, a bulb Of melted glas
and rolls the tube as in the process Of egJ
making, in tho meantime fashioning tn,
standard of the goblet. He then stick
q singular bulb on tho end of this, an,
forms Of it the base by holding smootl
fat piece Of wood against it while il /
10 rapid revolution. The goblet is thel
separated from the tube by holding
cold iron against it This causes circl
Of britiles, making breakage easy. Th
rough and superauous edge is remove
with the shears, after being rsheated, l
the goblot were now allowed to cool i
the open air, it would become extremel
lrargible. II must DO tempered, lik
steel. This is done in tho annealin
oven, brick structure open at both end
Underneath one end is q furnace, givip
it ap intense heat, which gradually d
minishes toward the other end sbou
thirty feet away. where the oven.be
would uot blister the hand, The bed
Of iron plates which are moved from th
hot end to tho cool. carrying on theI
the glasses which had been put into th
oven, but come out after period Of fron
eight to twenty. flour hours 10 conditio
to be taken 10 the naked hand. This
blown glassware. and is three times Q
costly as tho pressed or nodded. An al
ticle thus made has no angles. but ca
have surfaces out upon 1t by being hol
against q Gne Rriudstepo Ia reyolution