Nikola Tesla Books
A FOREWORD ON APPARATUS FOR THE STAGE 179 formers and lecturers alike. The very idea of "taking thousands of volts" of electricity through the body and still living to do it over again, is theatrical in the extreme, and it is no wonder that so many so-called electrical kings have separated a gullible public from their dollars for years on the sole claim that a supernatural or other unusual power made it possible for them to take current at this enormous voltage through their bodies. The high frequency coil may, therefore, be regarded as the one essential part of the outfit, and the other instruments in the light of accessories. Weight and Cost of Apparatus.-The largest apparatus described in this section will deliver sparks several feet in length. That this is spectacular and impressive, no one will gainsay, but the outfit weights hundreds of pounds and requires for its operation several kilowatts of electrical energy. The utter uselessness of such apparatus, in the case of the lecturer, is at once apparent. Far better is it for him to make or purchase a small coil capable of giving an eight or a ten inch spark and taking its current from the nearest lamp socket. Furthermore, the large apparatus requires for its operation an alternating current, and this is not always obtainable. The only practical alternative is a rotary converter or motor-generator set, which, in this large size, is very heavy and costly. The small coil, on the other hand, may be built on the "kicking coil" principle, described in an earlier chapter, and in such event its operation is satisfactory on either direct or alternating current through the change of a simple connection. The question of the high frequency outfit therefore resolves itself into one of whether the performance is to be given in a chain of small lecture halls or good-sized theatres. In the former case the small portable outfit
