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Still, the entire field of improvement is not occupied, and greater
advances will yet be made. The tendency, in this particular, has been
so to reduce the cost of glass that it has multiplied the consumption
at least tenfold; and there can be no reasonable doubt but that, at
this period, a much larger quantity of flint-glass is made in this
country than in England. The materials composing glass are all of
native production, and may be considered as from the earth. The pig
lead used is all obtained from the mines in the Western States; ashes
from various sources in other States; and silex is also indigenous.
The materials consumed yearly, in the manufacture, are something
near the following estimate:--
|Coal, for fuel . . . .
|Ash, Nitre, &c.,
for the flint manufacture. How much more is consumed by the window-glass
manufacturers, the writer is without data to determine.
We have recorded the progress of improvement
in the manufacture of glass, and now, relevant to the subject, we propose
to examine the various improvements in working furnaces and glass-houses.
To this end we present to