Which famous author was photographed in Tesla's lab in 1894?

The famous author photographed in Nikola Tesla’s laboratory in 1894 was Mark Twain, the pen name of Samuel Langhorne Clemens. The photograph shows Twain holding one of Tesla’s experimental lamps while Tesla is visible in the background of the laboratory.

The image came from Tesla’s high-frequency electrical demonstrations in New York. The lamp could glow without an ordinary wired connection, illustrating the striking effects of Tesla’s alternating-current and high-frequency experiments. Twain and Tesla were friends, and Twain was fascinated by the inventor’s demonstrations.

The photograph was later reproduced in Thomas Commerford Martin’s article “Tesla’s Oscillator and Other Inventions,” published in The Century Magazine in 1895. This sometimes causes confusion with another Tesla question: The Century Magazine did publish Tesla’s writing, but Mark Twain—not Tesla, Edison, or a fictional author—was the celebrity shown in the laboratory image. Twain’s real name was Samuel Clemens, which is why both names may appear in historical captions.