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
Gas Mark Gas Mark The Gas Mark is a temperature scale used on gas ovens and cookers in Great Britain, Ireland and some Commonwealth of Nations countries. The draft 2003 edition of the "Oxford English Dictionary" lists the earliest known usage of the concept as being in L. Chatterton's book "Modern Cookery" published in 1943: "Afternoon tea scones… Time: 20 minutes. Temperature: Gas, Regulo Mark 7". "Regulo" was a type of gas regulator used by a manufacturer of cookers; however, the scale has now become universal, and the word "Regulo" is rarely used. The term "gas mark" was a subject of the