"Chronoscope" for measuring reaction times, electrical mechanism in wooden case, lacks actuating switches, by National Institute of Industrial Psychology, London, early 20th century

Chronoscope made by the National Institute of Industrial Psychology(NIIP), London, and was used to measure reaction times in pyschological tests, c.1921-1939. A chronoscope is used for measuring small amounts of time, to an accuracy of 1/1000th of a second. They became popular with the emergence of laboratories of experimental psychology in the late 19th century, where they were used to try to determine the speed of thought.