Nikola Tesla U.S. Patent 645,576 - System of Transmission of Electrical Energy Patent Wrapper Page 56

174 practical advantage, that, whereas in all such methods or systems heretofore used or proposed but a minute fraction of the total energy expended by the generator or transmitter was recoverable in a distant receiving apparatus, by my method and appliances it is possible to utilize by far the greater portion of the energy of the source, and in any locality, however remote from the same. Expressed briefly, my present invention, based upon 41 consists these discoveries, consist then in producing at one point an electrical pressure of such character and magnitude, as to cause thereby a current to traverse elevated strata of the air between the point of generation and a distant point, at which the energy is to be received and utilized. In the accompanying drawing a general arrangement of apparatus is diagrammatically illustrated, such as I contemplate employing in the carrying out of my invention on an industrial. scale, as, for instance, for lighting distant cities or districts from places where cheap power is obtainable. Referring to the drawing, A is a coil, generally of many turns and of a very large diameter, wound in spiral form either about a magnetic core or not, as may be found necessary. C is a second coil formed of a conductor of much larger section and smaller length, wound around and in proximity to the coil A. In the transmitting apparatus the coil A constitutes the high tension secondary, and the coil C the primary of much lower tension of a transformer. In the circuit of the primary C is included a suitable source of current G. 12-30-99 -7This page retyped from microfilm for better readability - Ed.]