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
Action of 25 September 1917 Action of 25 September 1917 The Action of 25 September 1917 was a German methodical counter-attack ("Gegenangriff") which took place during the Third Battle of Ypres on the Western Front during the First World War. On the front of the British X Corps (Lieutenant-General Thomas Morland) at the south-east side of the Gheluvelt Plateau, two regiments of the German 50th Reserve Division attacked on both sides of the Reutelbeek stream, on a front. The was supported by German aircraft and and batteries of artillery, four times the usual amount of artillery for a German division. The German infantry managed to