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
German Type UE II submarine German Type UE II submarine The Type UE II submarines were a class of submarines built by the German Empire during World War I as long-range mine-layers. UE II boats carried 14 torpedoes and were armed with one 150 mm deck gun. They carried a crew of 40 and had a cruising range of about 9,400 miles. Nine were built between 1917 and 1918. The UE IIs joined the conflict in the middle of 1917, at a time when the tide of the war was turning against Germany. In the months beforehand, the United States Navy was added to the