June 20

1918: The X-ray expert Dr. Eugene W. Caldwell, died of X-ray burns in NY. 1840: Samuel Morse was granted a patent for telegraphy signals. 1935: The U.S. Army Air Force was established and headed by Gen. Hap Arnold, replacing the Army Air Corps. 1939: The world's first airplane to be propelled solely by a liquid-fuelled rocket, the Heinkel He-176, flew for first time. 1942: Japanese submarine I-25 launched an attack on Fort Stevens, located on the Columbia River in OR. 1950: Willie Mays graduated from high school and immediately signed with the New York Giants. 1977: The Trans-Alaska Pipeline began carrying oil from the Arctic Ocean to Prince William Sound. 1980: "Blues Brothers" with Dan Aykroyd and John Belushi premiered. 1981: Henri-Gaston Busignies, developer of HF (high frequency) direction finding equipment, died. 1996: Westinghouse Electric agreed to buy Infinity Broadcasting for $4.9 billion. 2006: IBM and the Georgia Institute of Technology demonstrated the first silicon-based transistor that operates at 500 GHz.