SHEET AND CROWN GLASS.
Comparison of sheet with polished plate--Raw materials
for sheet--Furnaces: various forms of tank furnaces--
Blowing process--Gathering, forming the gathering on
blocks, forming the shoulder of the cylinder, blowing
the cylinder, opening the end of the cylinder, detaching
cylinder from pipe--Cutting off the “cap”--Splitting
the cylinder--Flattening and annealing--Cutting and
sorting sheet-glass--Defects of sheet-glass--Variations
of the process--Attempts to produce “sheet” glass by
rolling--Sievert’s process--Direct drawing processes--
The American process for drawing cylinders--Fourcault’s
processes--Difficulties and limitations--Crown glass--
The blowing process--Limitations _p._ 149