2. Take 1/2 in.
of the platinum wire and slip it through the fine hole made by
breaking the glass thread so that one-half of the wire will be
inside of the long tube. If the end of the tube is now placed in
the flame of the burner, the glass will adhere to the platinum
wire and the wire will thus be sealed in the tube. The finished
end will appear as shown in Fig. 3. This tube as described will be
8 in. long, although nearly any size could be made in the same
way.
Measure 8 in. from the sealed end and place the tube at that point
in the flame, holding in the left hand. At the same time take the
piece of glass that was broken off at the end in the first
operation and hold it in the flame with the right hand. When both
the tube and piece of glass are soft, touch the soft part of the
tube with the end of the glass and draw the tube out into a point
like that shown in Fig. 4. Break off the piece of glass, thus
leaving a. small aperture in the long tube. Seal the remaining 1/2
in. of platinum in this aperture in the same manner as before
being careful not to heat the tube too suddenly. The tube is now
ready for filling and the upper part will appear as shown in Fig.
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