Nikola Tesla in his laboratory in Colorado Springs around 1899

Famous photograph of Serbian-American inventor Nikola Tesla in his laboratory in Colorado Springs around 1899, supposedly sitting reading next to his giant "magnifying transmitter" high voltage generator while the machine produced huge bolts of electricity. The photo was a promotional stunt by photographer Dickenson V. Alley; a double exposure. First the machine's huge sparks were photographed in the darkened room, then the photographic plate was exposed again with the machine off and Tesla sitting in the chair. In his Colorado Springs Notes Tesla admitted that the photo is false: "Of course, the discharge was not playing when the experimenter was photographed, as might be imagined!" Tesla's biographers Carl Willis and Mark Seifer confirm this. During 1899-1900 Tesla built this laboratory and researched wireless transmission of electric power there. The Magnifying Transmitter, one of the largest Tesla coils ever built, with input power of 300 kW could produce potentials of around 12 million volts at a frequency of about 150 kHz, creating 130 ft. (41 m) "lightning bolts". The arcs in the image are 22 feet long. When he first turned it on, the machine blew out the Colorado Springs power company's generator. These long arcs were not a feature of the normal operation of the coil because they wasted energy; for these photos Tesla forced the machine to produce arcs by switching the power rapidly on and off. The original image, without Tesla, appears in his magazine article Nikola Tesla, "The Problem of Increasing Human Energy", Century Magazine, The Century Co., New York, June 1900.