Nikola Tesla U.S. Patent 723,188 - Method of Signaling Patent Wrapper Page 49

606 the ^ ably chosen periods of vibration, such periods are meant as will secure the greatest safety against interference, both mutual and extraneous. The two systems may have electrical oscillations impressed upon them in any desired manner, conveniently by energizing them through primaries Pl and p2, placed in proximity to themt Adjustable inductances L¹ and 12 are preferably included in the primary circuits chiefly for the purpose of regulating the rates of the primary oscillations. In the drawings these primaries Pl and P2 surround the coils s1 s2, and are joined in series through inductances L1 L2, conductor F, condensers Cl and C2, brush holders B1 and 32 and a toothed disk D, which is connected to the conductor F and, if desired, also to the ground plate E, as shown, two independent primary circuits being thus formed. The condensers cl and c2 are of such capacity and the inductances 11 12 are so adjusted that each primary is in close resonance with its secondary system, as I have explained in other patents granted to me. The brush holders B1 and 32 are capable independently of angular and, if necessary, also of lateral adjustment, so that any desired order of succession or any difference of time interval between the discharges occurring in the two primary circuits may be obtained. The condensers being energized from a suitable source S, preferably of high potential, and the disk D being rotated, its projections or teeth p coming at periodically recurring intervals in very close proximity to or, as the case may be, in contact with conducting rods or brushes nn cause the condensers to be discharged in rapid succession through their respective circuits. In this ranner the two secondary systems, pl sl E and D² s2 E, are set in vi-5