Nikola Tesla Patents
508 }} in order to derive the fullest benefit from the improvement, to have the the circuit should be primarily constructed so as greatest possible self-induction and the smallest practicable resistance, and other rules of construction which are now recognized should be observed. For example, when in a system of transmission of energy for any purpose through the natural media, the transmitting and receiving conductors are connected to earth and to an insulated terminal respectively, the lengths of these conductors should be one quarter of the wave length of the disturbance propagated through them. Ja In the accompanying drawing I have shown graphically a disposition of apparatus, which may be used in applying practically my invention. The drawing illustrates in perspective two devices, either of which may be the transmitter, while the other is the receiver. In each there is a coil of few turns and low resistance, designated in one by A, and in the other by A'. former coil, supposed to be forming part of the transmitter, is to be connected with a suitable source of current, while the latter is to be included in circuit with a receiving device. In inductive relation to said coils in each instrument is a flat spirally wound coil B, or B', one terminal of which is shown as connected to a ground plate C, while the other, leading from the center, is adapted to be connected to an insulated terminal, which is generally maintained at an elevation in the air. The The coils B, B' are placed in insulating receptacles D, which contain the freezing agent and around which the coils A and A¹ are wound. Coils in the form of a flat spiral, such as those described J are eminently suited for the production of free oscillations, 1
