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
British home army in the First World War the New Army over the Territorial Force. Fear of invasion persisted throughout the first months of the war; Kitchener's decision was motivated in part by his concern that the Territorial Force should not be diverted from what he regarded as its primary task of defending the homeland. German success on the continent in September and October opened up the prospect of the French channel ports being used to launch an invasion that could outflank the main British coastal defences north of the Thames. To allow rapid redeployment of the Central Force across the river, construction was begun on a pontoon