The Union and eastern journal. [volume] (Biddeford [Me.]) 1854-1858, 1856-08-15

, ware and ornamental purposes, very larg
| proportion of red lead is added. So in tn
! diamond, it is from its exceedingly combui
, tible nature that It derives Its brilliant hues
: In glass when on sale, the presence Of tn
undesirable alkali is readily determined b.
the blue color seen in looking edgewise.-
The proper hue Of good glass edgewisc is ,
clear green.
The metal having been brought to prop
or state, the casting commences. The fur
mace, we should have mentioned, is raised
on platform. Before II stands bed o
cast iron, with smooth surface Of sixteen
by six feet area, and weighing thirteen tons
Along this are placed movable iron rails
technically tnngs-as far apart as the plate
is designed to be wide. On these, at one
end, rests a'cast iron roller Of four thousand
lbs, connected by chains and pulleys at the
other end. One of the door Of the furnace
is now opened, n pot is taken out, glowing
red, and glazed with overaowing metal. BY
means of a crane 1t is taken up, and the
contents taken before the roller. which, on
the instant, passes over 1t, reducing it to
the proper form. The pulleys, which rest
on little rail car, glide away. A movable
table, with plaster of Paris surface, takes
their place. Workmen with iron poles gen.
tly slide the new formed, still glowing and
flexible plate uponit, roll it across the room,
transfer it to the mealing ovens, and are
ready for another pot,-and 50 on through
the eight. This is Che most beautiful por-
ton of the work, both from the brilliancy
of the molten metal, and the clock-work
precision of the process, with the admirable
certainty of the result. In England, this
is accomplished with much characteristic
formality and dicipline, at the word of COM
mand and the sound of the horn. Here
every part of the process goes on without
word Of command, and with hardly re-
marx, k,-every man fitting his place, and
going through his part as though o part of
a great machine.
The annealing ovens are eight in number,
sixteen by twenty.four feet in area, with
perfectly even surfaces. They are heated
to about the temperature Of the glass when
1t is placed in them, and are then sealed up
and left to cool gradually for four or five
days, during which the glass acquires per-
manent elasticity, and perfect evenness Of
surface. II cooled suddenly, II would be
exceedingly brittle, so much so, in fact, rs
to crumble under its own weight. When
taken out, (if necessary into smaller sizes
and if not designed for windows or mirrors,
is ready for market. In this rough state
one side is smooth and clear, the other has
a surface similar to hammered metal. Ii is
in great demand for various purposes, prin-
cipally for partitions in building where
light is required in inner rooms. In many
buildings where light was formerly trans
mitted from the roof through an awkward
passage way, this glass has been substtu-
ted for roof, flooring, and sometimes ceiling,
giving much better and more abundant
light, besides saving room. Among their
numerous orders for this purpose, Is one for
the entire roof of tho famous Providence
Arcade, which is to be covered by two hun
dred and sixteen plates, four feet by fifteen,
and three-eights of an inch thick. The
flooring and some of the partitions arc to be
of the same material. When used for roofs
and flooring it is fitted in frames, generally
of iron, and the largest plates thus fitted are
capable of sustaining any weight required
of them.
Patents have also been taken out for the
application Of this material to the sound.
ing boards of pianos, and It will have an ad-
vantage wherever it is desirable to obtain
material not liable to warp or to absorb
moisture. So much for the rough plates.
The company look with very sanguine
expectations to the manufacture of polished
plates and mirrors, Us the great source OF
profits. In Europe, the process of polishing
is tedious and costly, being performed en-
tirely by hand, sometimes thousand women
being employed for this department Of n sim
gle mandatory. 1t is plain we could new
er compete with the foreign works in this
way, and the company, with hearty con
fdencc in Yankee genius, set about search
for machine to do the work-and found it.
It is very simple, consisting off round Ia
BILE with revolving top. This top is
sprinkled with the quartz sand, and sup
posing tho surface divided into four sections
for instance, plate Of glass is laid on each
section. A pin from above is screwed down
on the centre Of each plate, holding it fast
at that point. The top Of the table, turn
ing, grinds down the glass by its own mo-
ton, and at the same causes the plates to
rcvolve on their own axes, thus giving an
even surface to the glass. When this por-
ton Of the work is finished, the plates have
the appearance Of ground glass. They are
removed to another similar table, with n
felt covering sprinkled with some kind of
polishing powder, and the same motion is
renewed and kept up until the surface at
tains the finest possible polish. We only
wish this description of the process was half
As clear and perfect rs the glass is which it
produces.
Great credit is due to the company, and
especially to the agent and superintendent,
James N. Richmond, Esq. for the persever.
ence and talent which they have manifested
in bringing tho art Of manufacturing plate
glass to its present perfection. What has