First procure a wide-mouthed bottle about 4 in. high, provided with a rubber stopper.  This stopper should be pierced, making two holes about 1/4 in. in diameter.  From a sheet of lead 1/16 in. in thickness

[Illustration:  The Completed Instrument]

cut a piece shaped like A, Fig. 1.  Common tea lead folded several times will serve the purpose.  When in the bottle this lead should be of such a size that it will only reach half way around, as shown in B. To insert the lead plate, roll it up so it will pass through the neck of the bottle, then smooth it out with a small stick until it fits against the side, leaving the small strip at the top projecting through the neck of the bottle.  Bend this strip to one side and fit in the stopper, as shown in C. A small binding-post is fastened at the end of the strip.

Having fixed the lead plate in position, next get a piece of glass tube having a bore of about 1/32 of an inch in diameter.  A piece of an old thermometer tube will serve this purpose.  Insert this tube in the hole in the stopper farthest from the lead plate.  Get a piece of wire that will fit the tube and about 6 in. long, and fasten a small binding-post on one end and stick the other into the tube.  This wire should fit the hole in the tube so it can be easily moved.  In the hole nearest the lead plate insert a small glass funnel.

The interrupter as it is when complete is shown at D, Fig. 1.  Having finished the interrupter, connect it with the electric-light circuit as shown in Fig. 2.  Fill the bottle with water to about the line as shown in D, Fig. 1.  Adjust the wire in the small glass tube so that it projects about 1/8 in.  Add sulphuric acid until the water level rises about 1/16 in.  Turn on the current and press the button, B. If all adjustments are correct, there will be a loud crackling noise from the interrupter, a violet flame will appear at the end of the wire and a hot spark will pass between the secondary terminals.  If the interrupter does not work at first, add more sulphuric acid through the funnel and press the wire down a little more into the liquid.  A piece of wood, A, Fig. 2, should be inserted in vibrator to prevent it from working.  —­Contributed by Harold L. Jones, Carthage, N. Y.

** A Miniature “Pepper’s Ghost” Illusion [52]

Probably many readers have seen a “Pepper’s Ghost” illusion at some amusement place.  As there shown, the audience is generally seated in a dark room at the end of which there is a stage with black hangings.  One of the audience is invited onto the stage, where he is placed in an upright open

[Illustration:  Pepper’s Ghost]

coffin.  A white shroud is thrown over his body, and his clothes and flesh gradually fade away till nothing but his skeleton remains, which immediately begins to dance a horrible rattling jig.  The skeleton then fades away and the man is restored again.