Up: Glassmaking
Reminiscences
115 of 123
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| "Sample |
B |
analyses: 4000 parts of this sample contain
one part of oxide of iron. |
| " |
C |
analyses: 3333 parts of this sample contain
one part of oxide of iron. |
| " |
P |
analyses: 3460 parts of this sample contain
one part of oxide of iron. |
"Sample B is equal in purity to the best sand known as a material
for glass, in this or any other country."
FURNACES.
Next to pots, furnaces are most important for
the success of a glass manufactory. Long ago it was seen that the
old English plan was defective. They consumed coal at an extravagant
rate, though this was not a serious drawback in England, because the
furnaces were located near coal-mines, and run with a quality called
slack, not otherwise mechantable. English furnaces were constructed
with reference to durability, usually eight feet in diameter at the
interior base, and six feet clear at the crown. This rule was followed
in this country until 1840. The writer, having occasion to build an
extra furnace, adopted the novel plan of one fourteen feet diameter
at the base in the clear and only five feet at the crown, braced by
binders, with cross-ties to prevent lateral expansion, which was a
success.
A furnace on the old plan consumed 2575 bushels
of coal weekly, and refined only 38,000 pounds of raw material. The
new refined 35,000 pounds, with a consumption of only 2000 bushels of
coal. Since then a further decrease in consumption of coal has been
produced by the use of the Delano
patent, which feeds the furnace by forcing up the coal at the bottom
of the burning mass, thus consuming the entire smoke, and obviating
the necessity of wheeling coal on the glass-house floor and impeding
the workmen. It also does away with all danger to the pots in feeding
the fires. Besides these great advantages,
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