Chemical weapons in World War I volatile oily liquid. It was introduced as a vesicant by Germany in July 1917 prior to the Third Battle of Ypres. The Germans marked their shells yellow for mustard gas and green for chlorine and phosgene; hence they called the new gas "Yellow Cross". It was known to the British as "HS" ("Hun Stuff"), and the French called it "Yperite" (named after Ypres). Mustard gas is not an effective killing agent (though in high enough doses it is fatal) but can be used to harass and disable the enemy and pollute the battlefield. Delivered in artillery shells, mustard gas was
Nielsen & Winther Type AA Nielsen & Winther Type AA The Nielsen & Winther Type AA, also known as the Type AA, was a Danish fighter aircraft of the 1910s. The first Danish fighter aircraft to be conceived and built, the single seat Type AA was of wooden construction and powered by a 90 hp Thulin rotary engine. It was armed with two guns. The first flight took place on 21 January 1917. The plane was tested again in 1918, this time with synchronising gear for its single Madsen machine gun. During 1917 six Type AA aircraft were delivered to the Danish Army, though they