Julius ElsterBorn 24 Dec 1854; died 6 Apr 1920 at age 65.Johann Philipp Ludwig Julius Elster was a German physicist who had a very productive collaboration with Hans Geitel, and have been called the “Castor and Pollux” of physics.They constructed the first photelectric cell, and photelectric photometer as part of their study of the photoelectric effect and thermal electron emission. They declined to patent these inventions, preferring to share the benefits. From 1884, they researched electrical phenomena in gases, atmospheric electricity, measured the electrical field of the Earth, and in 1899 were the first to determine the charge on falling raindrops from thunderclouds. When they investigated radioactivity, they regarded it as due to a spontaneous release of energy by the atoms. They showed that lead is not in itself radioactive, and that conductivity of the atmosphere was due to ionization from radioactive substances.« |
