Removing the String
Cut a piece of heavy paper in the shape shown in Fig. 1 and make two cuts down the center and a slit as long as the two cuts are wide at a point about 1 in. below them. A string is put through the slit, the long cuts and back through the slit and then a button is fastened to each end. The small slit should not be so large as the buttons. The trick is to remove the string. The solution is quite simple. Fold the paper in the middle and the part between the long cuts will form a loop. Bend this loop down and pass it through the small slit. Turn the paper around and it will appear as shown in Fig. 2. One of the buttons may now be drawn through and the paper restored to its original shape.
Experiment with an Incandescent Lamp
When rubbing briskly an ordinary incandescent lamp on a piece of cloth and at the same time slightly revolving it, a luminous effect is produced similar to an X-ray tube. The room must be dark and the lamp perfectly dry to obtain good results. It appears that the inner surface of the globe becomes charged, probably by induction, and will sometimes hold the filament as shown in the sketch.
Contributed by E. W. Davis, Chicago.