The Union and eastern journal. [volume] (Biddeford [Me.]) 1854-1858, 1856-08-15
From the Brkshirs, (Mass.,) Eagle.
The Manufacture of Plate Glass.

Ihe introduction OF q new branch OF man.
ufactures into the County is always a sub
ject Of congratulation, and especially SO
when 1t is an art Of magnitude, and one not
before practised on this side the Atlantic.
If sketch of the glass manufacture, as car.
ried on by the National Plate Glass Com
pany, fails to interest our readers, II will
not, then, be the fault Of the subject.
The company has its financial head quar-
tiers at New York, and is composed princi-
pally Of capitalists of that city, who have
taken commcndable interest in the enter
prize.
The glass manufactured in its rough state
is in large translucent plates, Of any rcquir-
ed size, up to five feet six inches by sixteen
feet. In this state, although it transmits
light freely, no objects are visible through
it, and it is in great demand for ceilings,
floors, &C., in crowded houses. Tho same
article polished is equal to the best French
mirror plates.
The works Of tho company are on the
Housatonic Railroad at Lenox Furnace,
about FIVE miles from Pittsfeld. The prin.
cipal ingredient in bulk and cost used in
the manufacture, is the sand Of granular
quartz, for which this County is famous,
and which this company obtain from fine
bed on the summit of Washington noun
tain, close on the eastern border of Lake
Ashley. 1t is hauled about four miles. and
without the washing usual at other glass
works. With the sand is mixed rs. Aukcs
and discoloring agents, lime, soda, ash,
crude antimony, glauber salts, and some
times arsenic, in greater or less quantities,
us the quality Of the glass to be made de-
mands.
These ingredients, thoroughly mixed, are
placed in pots-crucibles of german clay
which will hold from three to six hundred
weight of metal, as the mass is technically
called when melted. The pots are then re-
moved to the furnace, which is also Of ger
man clay, with walls ten inches thick, and
having IN area Of about eight feet by ten.
Eight heavy doors on opposite sides admit
the pots and then are closed and packed
with clay. They are then subjected to an
intense heat from twelve to fourteen hours.
A single aperture Of perhaps eight inches
diameter admits the fuel, and II is curious
fact that the flame, which Is too intensely
fierce to be borne moro than moment by
the eye, and which, filing the whole fur
mace, belches through the openings over the
doors, is kept up by single stick Of baked
hemlock which tho workman places in this
aperture leaving one end protruding while
the other consumes. or course q consider
able portion of the combustion must be sup
piled by the gasscs generated from the melt
ING mass. In about ten or twelve hours
the glass is formed and becomes rs fluid a'
water. The FIRE Is then Stacked until the
metal assumes a waxy consistency, which it
docs in about two hours. The melting pro-
cess is one requiring great judgement, it bc-
ing necessary to burn out all the alkali, or
nearly so.- If there is neglect in this respect
or exposure to the air, the remaining alkaii
forms that iridcscent excrcsscnce on the sur
face Of the glass, which has given 80 bad
character to our old fashioned American
window glas. ltisa curious fact that fo'
the formation Of the prismatic colOrs some
combustible substance Is necessary, 90 thai
while In plate and window glas everything