CHAPTER X

ELECTRICAL PRINCIPLES

IN ELECTRICITY, we have a branch of physics that has rendered substantial aid to the cause of magic. The vast reputation gained by Robert-Houdin was in no small degree due to the facilities which, in its early days, electricity placed at the disposal of magicians. At the present time, no doubt, the continual spread of scientific knowledge has robbed electrical processes of their former mystery to a very great extent. We cannot now hang up a drum with electrical tappers concealed inside it, and expect an audience to be mystified by hearing that drum played invisibly. The day for that sort of thing has gone by, never to return. Yet, in spite of its shorn grandeur, electricity still remains a most valuable servant to the magician who takes the trouble to become its master.

Among magicians at large, there exists some prejudice against electricity, on the ground of its supposed uncertainty. There is an idea that electrical devices are essentially unreliable, and are subject to frequent failure at critical moments. It may be said at once, so far as electricity itself is concerned, that this charge of alleged unreliability is entirely without foundation. And with regard to electrical appliances, when a failure occurs it is due to some mechanical fault, ninety-nine times out of a hundred; and the fact of electricity being used as the motive power has nothing to do with the matter. If only the apparatus is properly constructed and installed, the electricity upon which its operation depends may be relied upon absolutely. There is no form of energy more certain in its action. But if the construction and installation of the mechanical devices are not efficiently carried out, there are bound to be failures and many of them. Then, in all probability, the blame will fall unjustly upon the electricity; instead of falling, as it ought, upon the tinker who made the appliances and the landscape gardener who put them in place.

It may be admitted, without argument, that the conditions in which electricity has to act when used for magical purposes, differ immensely from those with which it is normally associated elsewhere. The devices it has to control, when used in magic, are necessarily "tricky" in both structure and operation. For this reason, a motive power such as that of electricity, which depends for its efficiency upon the making of proper connections, necessitates some care in adaptation to the special circumstances of the case. This simply means that, if worked by electricity, tricky devices of faulty construction are more liable to play tricks than if they are operated mechanically. The moral is that string and sealing wax, not to mention elastic bands and tintacks, are not fit associates for electricity. Primitive materials of that nature may consort well enough with a box of conjuring tricks, as advertised; but an agent so refined as electricity demands other and better means for its employment.

The first principle set down in this group is the Conveyance of Power through Supports. Here, of course, entirely stationary and solid supports are understood. In other types of physical magic, there are devices by which power is conveyed through pillars, legs, cords, chains, or what not, to the appliances thereby supported. But in those other types, the devices must include some mechanical trickery in their construction, and some movement of or within the support itself. In the case of electricity, no such requirement exists. Electrical energy demands for its conveyance nothing beyond a continuous metallic circuit--a "line-wire" leading the current from a battery to the device it operates and a "return-wire" completing the circuit by leading back again to the battery. Thus two conductors are always necessary for electrically operated mechanism. These may readily be formed, either in or by the supports themselves. If the support is in itself a conductor, it will require to be insulated from all other conductors except the battery connection. If it is a non-conductor, a metallic core or other conducting attachment must be provided. Obviously, there must be two supports at least, if the current is actually conducted thereby. If there is only a single support, an insulated path must be provided internally. The double path being available, all that remains is to make sure of good contact between the ends of the two conductors and their appropriate connections. All being in order, one has only to press the button and electricity will do the rest.

The next electrical principle on the list is that of Trigger Action by Electric Current. In this, we have a means which should be useful for many purposes in the practice of magic. We say it should be so, because it has not as yet been adopted as frequently as its merits appear to deserve. The principle consists in the use of an electromagnet for releasing a motive power already stored up in a piece of apparatus. Thus any form of clockwork may be started or stopped, by moving its detent electrically. A supply of compressed air may be turned on and off, a spring released, or a weight allowed to fall. In short, there are a thousand and one operations in which trigger action is used, that may be most conveniently controlled by an electromagnet. There is also a great advantage in the fact that the magnet need have no contact with the device it moves. Its attraction will pass through all substances save those which are themselves magnetic. Therefore, so long as the distance across which the action has to take effect is not too great, the magnet and its "keeper" may be insulated from each other entirely.

The "Crystal Casket" of Robert-Houdin had another form of trigger-action by electric current. At a given instant, a wire, electrically heated, was caused to release coins concealed within the structure of the casket. Many devices of a similar character have been employed from time to time. The modern tendency, however, appears to be to rely upon threads, and primitive contrivances of that nature, rather than to adopt the more refined electrical methods. In some instances, no doubt, limitations of space would prevent the use of an electro-magnetic release; but, more often than not, it is possible to find room for some compact form of magnet. Therefore, it seems a pity that this convenient agency should be allowed to fall into such undeserved neglect.

The principle of communication by means of Electrotelegraphy or Telephony is so well understood, and its utility and convenience for special purposes of magic are so obvious, that nothing need be said about it by way of explanation or illustration.

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