September 7

1813: "Uncle Sam" was first used by Troy Post to refer to the U.S. 1912: Electrical engineer and entrepreneur David Packard, who co-founded the Hewlett-Packard Company, was born. 1914: American physicist James Van Allen, discoverer of the Van Allen radiation belts, was born. 1927: American television pioneer Philo Farnsworth, at age 21, transmitted the first image through purely electronic means by his "image dissector" invention. 1936: The Boulder Dam (now Hoover Dam) began operation. 1940: German Luftwaffe began a 57-night blitz on London. 1948: Louis Parker was issued a patent for his "intercarrier sound system" TV receiver, used still in modern TVs. 1963: The National Professional Football Hall of Fame was dedicated in Canton, Ohio. 1977: Jimmy Carter signed a treaty transferring control of Panama Canal on 12/31/1999. 1980: American chemist Willard Libby, who won the Nobel Prize for his development of carbon-14 dating, died. 1987: An agreement was signed in Copenhagen by 15 telecommunications operators from 13 countries that led to the development of the Global System for Mobile Communications (GSM). 1991: Edwin McMillan, who discovered neptunium and plutonium, died.