Page:Popular Science Monthly Volume 63.djvu/374

370 immensely improved this arrangement, as described by him in a lecture given before the Society of Arts, on May 17, 1901, by [sic]syntonizing the two circuits and making the circuit, consisting of the capacity of the aerial and the inductance of the secondary circuit of the oscillation transformer, have the same time-period as the circuit consisting of the Leyden jars, or energy-storing condenser, and the primary circuit of the oscillation transformer, and by so doing immensely added to the power and range of the apparatus.

Starting from these inventions of Braun and Marconi, the author devised a double transmission system in which the oscillations are twice transformed before being generated in the aerial, each time with a multiplication of electromotive force, and a multiplication-of the number of groups of oscillations per second. This arrangement can best be understood from the diagram (see Fig. 15).

 (Fleming), a, alternator; H1H2, choking coil; K, signaling key; T, step-up transformer; S1S2, spark gap; C1C2, condensers; T1T2, oscillation transformers; A, aerial; E, earth plate.

In this case, a transformer T or transformers, receive alternating low frequency current from an alternator a, being regulated by passing through two variable choking coils, H1 and H2, so as to control it. This alternating current is transformed up from a potential of two thousand to twenty, forty or a hundred thousand, and is employed to charge a large condenser C1, which discharges across a primary spark gap S1 through the primary coil of an oscillation transformer T1. The secondary circuit of the oscillation transformer is connected to a second pair of spark balls S2, which in turn are connected by a secondary condenser C2, and the primary circuit of a third transformer T2, and the secondary circuit of this last transformer are inserted between a Marconi aerial A and the earth E. When all these circuits are tuned to resonance by Mr. Marconi's methods, we have an enormously powerful arrangement for creating electric waves, or rather trains of electric waves, sent out from the aerial, and the oscillations are controlled and the signals made by short-circutingshort-circuiting [sic] one of the choking coils.

Another transmitting arrangement, which involves a slightly different principle, and employs no oscillation transformer, is one duo