The Cambria freeman. [volume] (Ebensburg, Pa.) 1867-1938, 1879-03-07
Mixing GLASS.

ed glass is made by melting together
sand or flint, and an alkah, Seither pot
ash or soda. For many centuries pre-
viOus to the Christian era the inven-
tion was known, although both the
date and the manner of its discovery
are uncertain. Some suppose that It
was found out by accident; the potash
contained in the ashes Of the wood
used bv party Of sailors, who had
made q large fire on the sea beach,
having been united by the heat with
the sand OF the beach and melted into
glass. This lucky accident is alleged
TO have happened on the coast Of Sy-
ria, where the earliest manufacture
Of glass unquestionably began.
All visitors to the Centennial EZ-
Libi.ion, 1t Philadelphia, viii recall
the process for gIass-manUfacture.-
They must have learned there, from
the exquisite variety of specimens dis
played. that the manufacture Of glass
has now been carried to = very high
degs-s of perfection. The materials
used for flint or white glass are sand,
potash, the preparations of lead, term
ed led lead, and liLhargc, wi-h s. small
quantity Of some other mineral sub
stance. After being well purified,
these are mixed, and then melted to-
gelLsr, being exposed to an intense
heat in large melting pots made Of
clay, and built into an immense furn-
ace The sand and potash are the es-
seutfaI articles IN the making Of glass.
But the lead is added in large quaint.
ties, as it is found 10 make the glass
mel. much more readily; also to give
/. greater bri.liaucy and to render It
less liable to crack. When these in
greiiauts are thoroughly melted and
united (Which process usually takes
lTo or three dlysJ the mouth of the
melting pot is opened ami the liquid
glass within is ready to be formed by
the workmen into any shape desired.
The mode adopted is TO take on the
end Of au iron tube some Of this sub
atance, which IS then in a moist, tena-
aiou5 aud plaster state, aud to blow
through the tube and roll the soft
mass on dat iron plates, pressing il
with various shaped tools. The work
man at lasts fashions it TO the shap,
desired, which it retains when cold.
Perhaps 10 other substance known
could be moulded into such q VARIETY
or forms for melted glass seems t,
exceed all things in It's ducLiIity an,
tanacity. It's consistencc is somethin,
between thai Of sof, putty and treacle
neither solid nor liquid, buc capable o
being bent. blown out pulled. prepared
twisted or cut, SO rs TO assume, at tn
wish of the workman, the variou
forms required.
When .he glass articles are mad
they have TO he auucaIed. that il
cooled slowly iu an oven for that pu
pose. III they ltJ not undergo TIA
process. they would crack on til
sIigutca- blow. and wcuId not wax.
liquids. The qualities that rende
glass SD valuable when manufacture.
are its hardness, and the polish of il
surface. which makes it so readily
he cIeaaseI. when soIed its beaut
fuI transparency, enabling it to pr
serve its contents when it is used
form vessels fJI liquids and its 3sir
50 incgrrosiye, that it is not acted u
on 10y au- ordinary substances, III
even by Che strongest acids, with oi
exception. It's value. again, as q su
stance for glazing windows dcpeu,
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