Nikola Tesla

“ The plates P and P', through which the electrical energy is conveyed to the brushes a and a', may be at a considerable distance from each other in the ground or one in the ground and the other in the air, preferably at some height. If but one plate is connected to earth and the other maintained at an elevation, the location of the apparatus must be determined with reference to the position of the stationary waves established by the generator, the effect evidently being greatest in a maximum and zero in a nodal region. ”

“ In a system for the transmisson of electrical energy, transmitting apparatus comprising a primary exciting circuit energised by a generator of alternating currents and a resonant secondary circuit of high selfinduction and small resistance loosely linked with the primary and adapted for throwing the terrestrial globe into resonance, as set forth. ”

“ It is known since a long time that electric currents may be propagated through the earth, and this knowledge has been utilized in many ways in the transmission of signals and the operation of a variety of receiving devices remote from the source of energy, mainly with the object of dispensing with a return conducting-wire. ”

“ The lowest frequency would appear to be six per second, in which case there will be but one node, at or near the ground-plate, and, paradoxical as it may seem, the effect will increase with the distance and will be greatest in a region diametrically opposite the transmitter. With oscillations still slower the earth, strictly speaking, will not resonate, but simply act as a capacity, and the variation of potential will be more or less uniform over its entire surface. ”

“ The art herein described for creating great electrical movements in the natural medium, which consists in estabilishing electrical waves of definite length and duration and impressing said waves upon said natural medium until the same becomes resonant. ”

“ In the above I have briefly outlined my discovery and indicated only a few uses of the same, but it will be readily seem, that it is of transcending importance for the advancement of many arts and industries, new and old, and capable of innumerable valuable applications. ”

“ The speed of rotation of the cylinder d being adjustable at will, the energy of any number of separate impulses may thus be accumulated in potential from and discharged through the receiver R upon the brush k coming in contact with one of the segments f. It will be understood that the capacity of the condenser should be such as to allow the storing of a much greater amount of energy than is required for the ordinary operation of the receiver. ”

“ In Fig. 1, A designates a primary coil forming part of a transformer and consisting generally of a few turns of a stout cable of inappreciable resistance, the ends of which are connected to the terminals of a source of powerful electrical oscillations, diagrammaticaly represented by D. This source is usually a condenser charged to a high potential and discharged in rapid succession through the primary, as in a type of transformer invented by me and now well known ”

“ It is also known that electrical disturbances may be transmitted through portions of the earth by grounding only one of the poles of the source, and this fact I have made use of in systems which I have devised for the purpose of transmitting through the natural media intelligible signals or power and which are now familiar ”