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
Tanks in the German Army at front and rear as well as several machine-guns, and reach a top speed of at least 12 km/h. The running gear was based on the Holt tractor, parts for which were copied from examples borrowed from the Austrian army. After initial plans were shared with the Army in December 1917, the design was extended to be a universal chassis which could be used as a base for both a tank and unarmoured "Überlandwagen" ("Over-land vehicle") cargo carriers. Powered by two Daimler engines, the tank was first demonstrated in the Spring Offensive of 1918. Internally, the Sturmpanzerwagen was cramped, smelly