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, a