American Aeroplane Gun.

New York Times 100 years ago today, August 21, 1912:
Tested at Belgian Military Aerodrome—Fires 500 Shots a Minute.
By Marconi Transatlantic Wireless Telegraph to The New York Times.
    BRUSSELS, Aug. 20.— Experiments with a quick-firing aeroplane gun of American invention have just been made at the military aerodrome at Brasschaet. The gun enables airmen to defend themselves from land attacks and hostile aeroplanes. It weighs 25 pounds and fires 500 shots a minute.