How It Is Made
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used are sand, gas-lime, and salt; but other materials are also employed
in different districts.
MAKING THE GLASS.
Flint-glass is fused out of contact with the
furnace flames, as the sulphur in the gases of combustion has an affinity
for lead and would cause discoloration. Fig. 57(6)
shows a pot used for melting flint-glass. The orifice at the top is arranged
opposite a hole in the furnace wall, through which the workman extracts
the "metal," as liquid glass is called.
Fig. 52.--Section of Glass Tank Furnace.
For window and bottle glass the tank furnace,
holding many tons, has now established itself. The tank is divided
transversely into three divisions by partitions which do not quite touch
the bottom, and is domed over (Fig. 52). At one end is a coal or gas fire,
the flames of which sweep from end to end of the