Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Friedrich Ernst Dorn (27 July 1848 16 December 1916) was a German physicist who was the first to discover that a radioactive substance, later named radon, is emitted from radium. Dorn was born in Guttstadt (Dobre Miasto), Province of Prussia, and died in Halle, Province of Saxony. He was educated at Königsberg and went on to teach at the university level. In 1885, at H ...