Tesla Wireless Illustration

Experiment in wireless power transmission by inventor Nikola Tesla at his Colorado Springs, USA laboratory in December 1900. The light glowing near the bottom is powered by energy transmitted wirelessly from the huge million volt, 300,000 watt magnifying transmitter in his lab nearby. The grounded "receiver" coil shown is tuned to resonance with the transmitter coil, and the lamp is powered by three turns of wire inductively coupled to the coil at bottom. The Century magazine article containing this picture does not say how far away the transmitter is. Information from Leland I. Anderson, Ed. (2002) Nikola Tesla on His Work with Alternating Currents and Their Application to Wireless Telegraphy, Telephony, and Transmission of Power: An Extended Interview, 21st Century Books, p. 97

Caption: Fig 4. EXPERIMENT TO ILLUSTRATE THE TRANSMISSION OF ELECTRICAL ENERGY THROUGH THE EARTH WITHOUT WIRE. The coil shown in the photograph has its lower end or terminal connected to the ground, and is exactly attuned to the vibrations of a distant electrical oscillator. The lamp lighted is in an independent wire loop, energized by induction from the coil excited by the electrical vibrations transmitted to it through the ground from the oscillator, which is worked only to five per cent. of its full capacity.