Nikola Tesla Patents
J 1 T T T T sion, and remain open or closed during such intervals of time, as may be desired. 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. On the other hand, plates if both be connected to Earth, the points of connection must be selected with reference to the difference of potential which it is desired to secure, the strongest effect being, of course, obtained when the plates are at a distance equal to half the wave length. # In illustration of the operation of the system, let it be assumed that alternating electrical impulses from the generator are caused to produce stationary waves in the Earth, as above described, and that the receiving apparatus is properly located with reference to the position of the nodal and ventral regions of the waves. The speed of rotation of the cylinder D is varied until it is made to turn in synchronism with the alter nate impulses of the generator, and the position of the brushes band bis adjusted by angular displacement, or otherwise, so that they are in contact with the segments S and St during the periods when the impulses are at, or near, the maximum of their intensity. These requirements being fulfilled, electrical charges of the same sign will he conveyed to each of the ter-10545
