Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1882-04-18
LOW PInle.l;llSs is Made,


It is not very well known that nearly
all the plate glass so common nowadays
is manufactured on the other side OF
the ocea~ and imported here, though the
home business is prot, cted by duty
80 per cent. The manufacture ofplate-
glass vas in Europe originally con-
,rolled by the royal families and the
process Of it's manufacture was royal
secret. st the present day the most
skillful workmen in tho factories OF
France and Belgium earn 5000 year,
aad consequently have no reason for
euisratipg. As a rule the artisans that
DO come here are inferior workmen.
Plate glass is manufactured too hastily
here. Tie art is fine one, and the
utmost patience and skill is needed to
produce the finest article. The largest
plate1lass ever exhibited in this
country was that seen at the Centennial
III 1876. It's dimensions were twenty.
two feet 10y ten feet six inches. 1t was
manufactured in France. This plate
in its entirety never had any practical
use, and was aiterward cut up and
used. The largest plate made in this
country was nine feet in length.
The process OF manufacture is very
long and tedious. The glass IS melted
in large clay pots holding about
thousand pounds OF liquid each, which
is subjected to very intense heat.
The most advanced manufacturers use
the "Siemens gas-burner. for the use
Of which in this country a very large
royalty is charged. The preparation OF
The pots is most important. They are
:aade Of German or "Stourbridge"
clay, and to properly dry them from five
to six months are required. Unless thor
ougbly made there is liability Of break
nge in the fire, involving the
loss of the pot and its con-
tents-s loss OF about 500. When
the "batch" has been sufficiently
melted the furnace door is opened and
by means OF q crane the pot is elevated
and the metal cast upon heated steel
table. Over the molten mass a heavy
roller is drawn which produces a level
surface. When partially cooled the
plate is pushed into carriage
which has a surface of mortar. 1t is
then rolled rapidly into snnealing
ovens where it remains until it is proper
ly tempered. The glass is now what is
commonly known as trough plate
glass" and 80 much Of it as is not sufli-
ciently good in quality is subjected to
the further expense of grinding and
polishing and is sold for sky-lights and
yault-lights. Now the plate is fit for
grinding. The methods Of doing this
differ somewhat in different factories.
although the common practice is to put
two plates OF glass together and then
move them rapidly one over the other.
Very ingenious machinery is used in
England for the succeeding stages.
The glass is cast usually of athickness
Of one-half inch, but by the successive
processes OF grinding is reduced to as
near one-quarter Of On inch as possible.
II the surface is free from defects
nnd uniform when the thickness OF
three eighths Of an inch has been
reached, the plate is finished, as the
thickness is not Objectionable, although
one-quarter OF an inch is the standard.
The final polishing is done by hand,
and large numbers OF girls and children
are employed in many of the factories
for this purpose. 1t is not uncommon
that at this stage Of the manufacture
an accident will break into fragments
the finished plate. The pieces are
gathered up and melted over again to go
through the same process. After com.
pletion OF the polishing the plate is
carried to the stock-room and there
awaits its sale.