the "neck" of the cylinder in which condition the pipe
with the pear-shaped mass of glass is passed to the
"blower" who reheats the mass at the blow furnace and
then swings the pipe over the "swing hole," or alley,
alongside of the furnace.
By highly skillful heating, blowing,
reheating and dextrous manipulations, the cylinder is
elongated, the sides being kept as nearly as possible to
the desired thickness necessary to produce either single,
double or heavier sheets.
These intermittent operations are
carried on until the bottom of the cylinder is of the same
thickness as are the sides. This closed end is then
exposed to the heat of the blow furnace while the workman
at the same time blows into the pipe and then by placing
his thumb over the end confines the air under slight
pressure. The air, being expanded by the heat from the
furnace, finally bursts out through the bottom (Fig. 4).
The cylinder with its ragged, open end, thus produced,
is again
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