Columbia Encyclopedia

(Encyclopedia) Davis, Benjamin Oliver, Jr., 1912–2002, American air force general, b. Washington, D.C.; son of Benjamin Oliver Davis. After studying at Western Reserve and Chicago universities, he attended West Po...

(Encyclopedia) compressed air, air whose volume has been decreased by the application of pressure. Air is compressed by various devices, including the simple hand pump and the reciprocating, rotary, centrifugal, and...

(Encyclopedia) United States, Great Seal of the, official impression that validates a United States government document. It was adopted by the Continental Congress in 1782 and, with only minor changes in the design,...

(Encyclopedia) Seal of the United States, Great: see United States, Great Seal of the. ...

(Encyclopedia) Great Seal of the United States: see United States, Great Seal of the. ...

(Encyclopedia) Congress of the United States, the legislative branch of the federal government, instituted (1789) by Article 1 of the Constitution of the United States, which prescribes its membership and defines it...

(Encyclopedia) air traffic control, the system by which airplanes are safely routed into and out of major airports. Air traffic control in the United States is centered in a number of regional control centers that r...

(Encyclopedia) Arnold, Henry Harley, 1886–1950, American general, chief of the U.S. Army Air Forces (1942–46), known as “Hap” Arnold, B. Gladwyne, Pa., grad. West Point, 1907. Assigned (1911) to the aviation...

(Encyclopedia)  CE5 Cross section of air conditioning unit. air conditioning, mechanical process for controlling the humidity, temperature, cleanliness, and circulation of air in buildings and rooms. Indoor air i...

(Encyclopedia) Symington, William Stuart, 1901–88, U.S. senator (1953–76), b. Amherst, Mass. He interrupted a successful business career in 1941 to accept a War Department assignment involving a study of airplan...