1967 Event New York Times reports Army is conducting secret germ warfare experiments 1965 Event U.S. confirms its troops used chemical warfare against the Vietcong 1944 Event 1st use of helicopters during warfare (British Atlantic patrol) 1920 Event General Amos Fries appointed 1st U.S. Army chemical warfare chief 1918 Event Christy Mathewson resigns as Reds manager to accept a commission as a captain in chemical warfare branch of Army 1916 Event At request of U.S., Germany curtails its submarine warfare 1916 Event German parliament OKs unrestricted submarine warfare
