king an exhaustion branch,
given on page 18, blown articles may also be constructed from rod. Note
the added parts of _e_, Fig. 9.

_A Simple Foot._--The form of foot shown by Fig. 7, _k_, is easy to make
and has many uses. First join a glass rod to a length of glass tubing as
shown (the joint should be expanded slightly by blowing), cut off the
tube and heat the piece remaining on the rod until it can be turned out
as shown by _i_. This should be done with the large turn-pin, and care
should be taken not to heat the supporting rod too strongly, otherwise
the piece of tube will become bent and distorted; it is better to
commence by heating the edge of the piece of tube and turn out a lip,
then extend the heating by degrees and turn out more and more until the
foot looks like that shown by _i_.

We now need to make three projections of glass rod. These are produced
as follows:--Heat the end of the glass rod until a thoroughly melted
mass of glass has accumulated (the rod must be rotated while this is
being done, otherwise the glass will drop off); when sufficient melted
glass has been obtained, the edge of the turned-out foot should be
heated to dull redness over about one-third of its circumference, and
the melted glass on the rod should be drawn along the heated portion
until both are so completely in contact as to form one mass of
semi-fluid glass. The rod should now be drawn away slowly, and, finally,
separated by melting off, thus producing a flat projection. A repetition
of the process will give the other two projections, and the finished
foot may be adjusted to stand upright by heating the projections
slightly and standing it on the carbon plate mentioned on page 7. After
the foot is adjusted it should be annealed slightly by heating to just
below the softening point of the glass and then rotating in a smoky gas
flame until it is covered with a deposit of carbon, after which it
should be allowed to cool in a place free from draughts and where the
hot glass will not come in contact with anything. The finished foot is
shown by _k_, Fig. 7.

_Building up from Glass Rod._--A glass skeleton-work can be constructed
from rod without much difficulty, and is sometimes useful as a container
for a substance which has to be treated with acid, or for similar
purposes. The method is almost sufficiently explained by the
illustration in Fig. 7; _f_ shows the initial stage, _g_ the method of
construction of the net-work, and _h