On August 2, 1932, while photographing cosmic-ray tracks in a cloud chamber, Carl Anderson captured on film the track left behind of the first clearly identified positive electron. This photograph shows the particle moving upward, as determined by the increase in curvature of the top half of the track after it passed through the lead plate, and curving to the left, meaning its charge is positive. Anderson won the Nobel Prize in physics in 1936 for this discovery., Carl Anderson Papers 5.10.
