Experiment 16. The ancient spider trick.
FIG. 30
ATTACHING A HANDLE
Attach an imitation spider—or the dead body of a real spider—to the end of the glass spider-web and surprise your friends, as shown in Fig. 29. The glass spider-web is much less visible than a thread for this purpose.
Experiment 17. To make working handles.
You can save glass in many cases by attaching a short piece of glass to the piece you intend to work with, as follows: Heat an end of each piece in the lamp flame until red hot, press them together, remove from the flame, and hold until solid. The short piece then serves as a working handle (Fig. 30) for the large piece.
Experiment 18. To close a large tube.
You closed small tubes in Experiment 5 by simply heating the end in the blowpipe flame. This method does not serve for large tubes, however, because it leaves a very large lump of glass which may crack on cooling or reheating.
FIG. 31
CLOSING A LARGE TUBE