Nikola Tesla Books
[Sec. 4.b. (1), cont.] distance of 300 feet from the laboratory." [Nikola Tesla, "The Problem of Increasing Human Energy," Century Magazine, June 1900, pp. 175-211; quoted observation from caption to Fig. 8.]
"I could walk on the sand (ordinarily considered a very good insulator) several hundred feet from my large high frequency oscillator, and sparks jumped from my shoes! At such distances all incandescent lamps glowed by wireless power, and banks of lamp, connected to a few turns of wire arranged in a coil on the ground, were lighted to full brilliancy. [*] The effect on metallic objects at considerable distances was really remarkable... I succeeded in producing the most powerful X-rays ever seen. I could stand at a distance of 100 feet from the X-ray apparatus and see the bones of the hand clearly with the aid of a fluoroscope screen; and I could have easily seen them at a distance several times this by utilizing suitable power." [H. Winfield Secor, "Tesla's Views on Electricity and the War," Electrical Experimenter, August 1917, pp. 229-30, 270; quoted remarks of Tesla at p. 230.]
"In my experiments in Colorado, when the plant was powerfully excited, the lightning arresters for twelve miles around were bridged with continuous arcs, much stronger and more persistent than those which ordinarily took place during an electric storm... When the oscillator was excited to about 4,000,000 volts and an incandescent lamp was held in the hand about fifty or sixty feet from the laboratory, the filament was often broken by the vibration set up, giving some idea of the magnitude of the electromotive forces generated in the space. The accompanying illustration shows one of my experiments in which I lighted several lamps at a distance of 100 feet from the laboratory, purely by wireless energy [*]... When the large transmitter coil, 51 feet in diameter, which I had in the center of the laboratory, was powerfully energized, butterflies were carried around in a circle as in a hurricane and could not get out, no matter how they tried. I was unable to satisfactorily explain the gyrations in the circle, altho [sic] I can well understand that the charged coil might, by repulsion, keep them in the center. Perhaps the most remarkable of all the observations was the production of sparks in the sand when one walked at some distance from the building. At night a continuous stream of tiny sparks could be seen between the heels and the earth and between the grains of sand..." [Nikola Tesla, (in) "Can Radio Ignite Balloons?" Electrical Experimenter, October 1919, pp. 516, 591-94; quoted remarks at p. 591.]
COMMENT: With respect to the remarks identified by *, above, this writer is somewhat taken aback by the interpretation of Tesla that these lamps (three in the illustration) were illuminated by anything else then purely inductive effects from the Magnifying
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