Arthur H. Bell

The possessor of an induction coil giving an inch spark or over, may construct, at small expense, a number of interesting accessories with which to amuse himself and friends.

The first device, Fig. 1, is constructed of wire and a pivot turned or drilled and filed out of brass rod. Because of the direction given to the wire and points, the electric discharge at the gap causes the device to revolve in a remarkable manner, as long as the coil is in operation.

Fig. 1.

Another device, which is simply made and can be developed into a fascinating display for store windows or other exhibition purposes, is the tempest display, illustrated in Fig. 2. The houses, church, flag pole and trees may be designed in any shape desired, but must be whittled out of soft wood and painted in natural colors. All of these houses rest permanently on a metal plate, which may be covered with sand to more closely resemble the earth. All of the objects, whether houses or trees, must have the uppermost portions connected with the metal base by a fine concealed iron or copper wire, which plays a very important part in the successful operation of the device. Above the houses and trees is suspended, by fine wires, a sheet of metal screening, such as fly screening. This screen is connected to the positive terminal of a spark coil and the metal plate to the other terminal. When the coil is set in operation, sparks play about the trees and church spires just as they often do in summer tempests. Though described in crude form, this scheme is worthy of development, and bright amateurs possessing coils will readily perceive the ways of perfecting a regular landscape, with sky, storm clouds and artificial downpour. The writer built such a device a few years ago, and had the pleasure of seeing it in constant use for several weeks in a prominent store window, and realizing therefrom a considerable revenue for the rental of what every one declared to be the successful window display of the year.

It is also possible to construct an attractive display by using pith, taken from corn or cane stocks. Pith is an article of commerce and may be readily purchased of apparatus dealers, and often of druggists. Little balls of pith when inserted loosely between plates such as were described for Fig. 2, will jump and bob about in an animated manner, and if puppets of pith are constructed to resemble persons, dogs and other animal life, their remarkable antics will cause much speculation and amusement for the uninitiated.

The writer once purchased quite a large ball of pith and decorated it with colored inks. This ball was fas-tened to a stout straw and counterbalanced by a shoe button at the other end. The see-saw-like affair was suspended from the upper plate, half way down, by a fine silk fiber, and as the fittings of the device, including the sheets of metal were all painted a dull black, it was impossible for any outsider to tell the cause of the wonderful see-saw motion.

Another simple device is to write a name on a strip of black cardboard and punch out the lines with a stout needle or awl. This card is placed close to and in front of the spark gap of the Rhumkorff coil, and in the dark the illumination of the letter is very fascinating.

Fig. 2.

The writer also remembers a mouse trap altered to cause instant death to the mouse, when the trigger was released. Most readers are accustomed to the round red mouse traps which have five or more holes into which the hungry creature thrusts his head, only to be gripped by a noose of iron wire actuated by quite a powerful spring. One of these mouse traps was placed on a metal plate, and the-trigger and spring so arranged for a wipe contact that when the cheese bait was moved inside the primary of the induction coil was set in operation and a current of high voltage sped through the mouse's body, bringing instant death. The secondary of the coil was connected to the metal plate and to another little plate just inside the hole, not actually in direct contact with plate number one. There are many other simple ways that a small coil can be utilized, and of these the writer may treat in succeeding numbers, with the hope that his amateur friends will try all the experiments and endeavor to devise new and original ones.