Nikola Tesla U.S. Patent 645,576 - System of Transmission of Electrical Energy Patent Wrapper Page 59

( 1 J J ( C 1 D wires, this condition should be complied with in order to attain the best results. As the main requirement in carrying out my invention is to produce currents of an excessively high potential, this object will be facilitated by using a primary current of very considerable frequency, since the electro-motive force obtainable with a given length of conductor is proportionate to the freq ency, but the frequency of the current is, in a large measure, arbitrary, for if the potential be sufficiently high, and if the terminals of the coils be maintained at the proper altitudes, the action described will take place, and a current will be transmitted through the elevated air strata, which will encounter little, and possibly even less resistance, than if conveyed through a copper wire of a practicable size. Accordingly, the construction of the apparatus may be in many details greatly varied, but in order to enable any person skilled in the mechanical and electrical arts to utilize to advantage, in the practical applications of my system, the experience I have so far gained, the following particulars of a model plant, which has been long in use and which was constructed for the purpose of obtaining further data to be used in the carrying out of my invention on a large scale, are given. The transmitting apparatus was in this case one of my electrical oscillators which are transformers of a special type, now well known and characterized by the passage of oscillatory discharges of a condenser through the primary. The source G, forming one of the elements of the transmitter, was a condenser of a capacity of -10This page retyped from microfilm for better readability - Ed.] 177