Auguste Piccard, (1884-1962), Belgium #252 signed by him. The stamp commemorates his two balloon flights in 1932 (May and August) into the Earth's stratosphere (51,775 and 53,153 feet above sea level) to measure upper atmosphere data and cosmic radiation. Piccard was a physics professor at the Free University of Brussels in Belgium. He also invented the bathyscaphe, which took a man down to 13,701 feet below sea level, safely (Image)

$300