Nikola Tesla - Free-Energy Devices

HIGH FREQUENCY AND HTGII POTENTIAL CURRENTS. 403Leyden jar, which combines the two essentials of a current whose maximumvalue is enormous, and whose rapidity of alternation isimmensely great. Thedischarge circuits, which may take the shape of bulbs, or of tubes bent in theform of coils, were placed in close proximity to glass tubes filled with mercury,which formed the path of the oscillatory discharge. The parts thus correspondedto the windings of an induction coil, the vacuum tubes being the secondary,and the tubes filled with mercury the primary. In such an apparatusthe Leyden jar need not be large, and neither primary nor secondary need havemany turns, for this would increase the self-induction of the former, andlengthen the discharge path in the latter. Increasing the self-induction of theprimary reduces the E. M. F. induced in the secondary, whilst lengthening thesecondary does not increase the E. M. F. per unit length. The two or threeturns, as shown in Fig. 216, in each, were found to be quite sufficient, and, ondischarging the Leyden jar between two highly polished knobs in the primaryFIG. 218. FIG. 219.circuit, a plain uniform band of light was seen to pass round the secondary.An exhausted bulb, Fig. 217, containing traces of oxygen was plaeed within aprimary spiral of three turns, and, on passing the jar discharge, a circle of lightwas seen within the bulb inclose proximity to the primary circuit, accompaniedby a purplish glow, which lasted for a second or more. On heating thebulb, the duration of the glow was greatly diminished, and it could be instantlyextinguished by the presence of an electro-magnet. Another exhaustedbulb, Fig. 218, surrounded by a primary spiral, was contained in a bell-jar,and when the pressure of air in the jar was about that of the atmosphere, thesecondary discharge occurred in the bulb, as is ordinarily the case. On exhaustingthe jar, however, the luminous discharge grew fainter, and a pointwas reached at which no secondary discharge was visible. J urther exhaustionof the jar caused the secondary discharge to appear outside of the bulb. Thefact of obtaining no luminous discharge, either in the bulb or jar, the author