July 15

1868: William Morton, the first dentist to use ether (letheon) during a tooth extraction, died. 1869: Hippolyte Mège Mouriés patented margarine following a contest held by Emperor Napoleon III to find a suitable substitute for butter used by the French Navy. 1904: Pavel Cherenkov, who discovered the radiation bearing his name, was born. 1916: The Boeing Company, originally known as Pacific Aero Products, was founded in Seattle by William Boeing. 1933: Wiley Post began the first solo flight around world. 1940: The first betatron was placed in operation, Urbana, IL. 1943: Astronomer Jocelyn Burnell, who discovered the first four pulsars, was born. 1944: The Greenwich Royal Observatory was damaged by German V1 "Buzz Bomb." 1952: The first transatlantic helicopter flight began. 1954: The Boeing 707 - the first commercial jet transport airplane built in U.S. - was tested. 1955: The first electric power generated from atomic energy to illuminate an entire town was obtained from the Utah Power and Light Company's station in Arco, Idaho. 1965: The spacecraft Mariner IV sent back the first close-up pictures of the planet Mars. 1965: Congress passed a law requiring all cigarette packages to carry a health warning. 1975: Three American astronauts blasted off aboard an Apollo spaceship hours after two Soviet cosmonauts were launched aboard a "Soyuz" spacecraft for a mission that included an Apollo-Soyuz linkup of the two ships in orbit. 1975: The Detroit Tigers trademark was registered. 1996: MSNBC made its debut on cable and the Internet. 1999: China declared that it had invented its own neutron bomb.