On this day, Aug. 1

1907 The U.S. Army Signal Corps established an aeronautical division, the forerunner of the U.S. Air Force.

1911 Harriet Quimby became the first woman to receive a U.S. pilot’s certificate from the Aero Club of America. (Quimby’s accomplishments included being the first woman to fly across the English Channel; she was killed in an accident in July 1912 at age 37.)

1940 A reorganization plan, consolidating 55 interlocking street transit systems into a single company, was filed in federal court by trustees for the bankrupt Pittsburgh Railways Co.

1966 Charles Joseph Whitman, 25, went on an armed rampage at the University of Texas in Austin that killed 14 people, most of whom were shot by Whitman while he was perched in the clock tower of the main campus building. (Whitman, who also had slain his wife and mother hours earlier, was finally gunned down by police.)

1981 The rock music video channel MTV made its debut.

1990 Despite public and union protests, Dorothy Six, a blast furnace at USX Corporation’s Duquesne works, was demolished.

2001 Pro Bowl tackle Korey Stringer, 27, died of heat stroke, a day after collapsing at the Minnesota Vikings’ training camp on the hottest day of the year.

2005 The Pittsburgh Ballet Theatre announced it would replace the musicians of the Pittsburgh Ballet Theatre Orchestra with recorded music for its 2005-06 season.

2013 Defying the United States, Russia granted Edward Snowden temporary asylum, allowing the National Security Agency leaker to slip out of the Moscow airport where he had been holed up for weeks. Some items are from Stefan Lorant’s “Pittsburgh: The Story of an American City” (digital.library.pitt.edu/chronology).