--Contributed by R. J. Smith, Milwaukee, Wis.
** How to Make a Small Geissler Tube [154]
At first this would seem to be a difficult piece of work, yet a
good and beautiful Geissler tube can be made at home in the
following manner:
Procure a glass tube about 3-1/2 ft. long having a hole through
its center about 1/8 or 1/4 in. in diameter, about 1 in. of No. 30
platinum wire and enough mercury to fill the tube and a small
bowl. About 1-1/2 lb. of mercury will be sufficient. The first
thing to do is to seal 1/2 in. of platinum wire in one end of the
tube. This is done by holding the end of the tube with the right
hand and taking hold of the tube with the left hand about 4 in.
from the right hand. Hold the tube in a flame of a bunsen burner
in such manner that the flame will strike the tube midway between
the hands, as shown in Fig. 1, and keep turning the tube so as to
get an even heat. When the glass becomes soft,
[Illustration: Construction of Geissler Tube]
remove the tube from the flame and quickly draw it out into a fine
thread. Break this thread off about 1/8 in. from the long part of
the tube and the end will appear as shown in Fig.
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