March 13

1773: Joseph Priestley, discoverer elemental oxygen, ammonia, hydrochloric acid gas, carbon monoxide, sulfur dioxide, and oxides of nitrogen, was born. 1781: The planet Uranus was discovered by Sir William Herschel. 1842: Henry Shrapnel, inventor of the type of mortar that bears his name, died. 1855: Percival Lowell, the American astronomer who helped discover Pluto and believed that there was life on Mars, was born. 1933: Astronomer Robert Innes, who discovered Proxima Centauri, the closest star to our sun, died. 1937: Elihu Thomson, electrical engineer and inventor whose discoveries in the field of alternating current led to the development of successful alternating current motors, died. 1886: Albert Stevens, who took the first photograph of Earth showing its curvature, was born. 1989: A series of solar flares caused a violent magnetic storm that brought power outages over large regions of Canada.  1992: The FCC ruled companies can own 30 AM and 30 FM stations. 1998: German engineer Hans von Ohain, who developed the first operational jet engine (HeS3b used in the Heinkel He 178), died.