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the furnace, are well known. For many years the prepared wood we have
spoken of was used. Then resin in a powdered state was added, which
was both inconvenient and dangerous,-- it having caused the destruction by
burning of two glass-houses. This risk was finally overcome by the
introduction of an invention which used it in a liquid state. But the
demand for resin became so great as soon to more than double its price.
This led to the substitution of coal tar, which was in use until science
discovered its latent virtues for other purposes, and largely increased
the original cost of the material. Indeed, at first the gas companies
had considered it of no value, and had thrown it away by thousands of
barrels. Combined with dead oil it is still used by glass-makers, but at
greatly enhanced prices.|
The Cape Cod Glass
Company have had in use for several years a Delano patent furnace-feeder,
which enables them to use both hard and soft coal, as either is cheapest,
and consumes the smoke and gas of either fuel, thus doing away all
annoyance to the neighborhood. Theretofore every attempt to run working
places with hard or soft coal had failed on account of the noxious gases
set free, which injure the color of the glass. But owing to the intense
heat created by the Delano patent, the furnace consumes these gases, and
gives a quick fire polish to the various articles finished therein.
As our native supplies of hard and soft coal are
inexhaustible, there is no likelihood of an increase in the price of the
present fuel so as to necessitate, as heretofore, a substitution of some
cheaper article, especially as the discovery of petroleum tends to cheapen
coal by a diversion of a portion of its consumption to that useful
A bushel of English coal weighs 80 pounds; of
Virginia coal, 93 pounds; of Pictou, 76 pounds; of Cumberland, 84 pounds;
of red ash, hard, 85 pounds.
Crude saltpetre, refined, loses nine per cent.