Glass-blowing requires great practice and manual dexterity, for the
material used being red-hot cannot be touched with the hands, and
has to be very rapidly worked, or it becomes cooled and hard; to
any one unused to work with it, it is the most unmanageable material
conceivable, but by practice the glass-blower contrives to produce
almost any form required, and of a size quite astonishing--as, for
instance, the globular bottles seen in druggists’ windows, which
often hold twelve gallons, also glass shades, which are of an uniform
thickness, and two or three feet high. This is all done by means of a
hollow rod of iron called a “puntil,” on the one end of which a mass
of molten glass is collected (fig. 1), and the workman blows into
the other, at the same time turning the tube rapidly round in his
hands (fig. 2). When the kind of glass called “crown-glass” has to be
made, the end of the iron tube is put into the pot of melted glass,
and turned round till a ball of it is collected about the size of
one’s head, the workman then blows in at the other end, still turning
the rod in his hands; it has now the appearance presented at fig.
3. An iron rod is stuck on to the side of the globe opposite to the
“puntil,” which is then pulled suddenly away, leaving a round hole.
The globe of glass is again made red-hot, and spun round rapidly,
the hole increasing in size until it resembles fig. 4. By continuing
the rapid twirling of the rod, the hole opens wider and wider till
at last one broad sheet is produced; it is then separated from the
rod by putting a drop of cold water at its junction with the glass,
which causes it to crack across at that part. It is now about six
feet in diameter, perfectly round and flat, and when cold it is cut
into halves and packed with straw in a “crate” for carriage. The knot
of glass often seen in kitchen or stable windows, is the part in the
centre of the glass where the iron rod has joined it, and is called
the “punty.”