5924515 Corporal Joseph Egerton of the Shropshire Yeomanry in gas mask, 1917 circa (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: Corporal Joseph Egerton of the Shropshire Yeomanry in gas mask, 1917 circa. Photograph, World War One, Egypt and Palestine (1914-1918), 1917 circa. Egerton wears a small box filter respirator, a gas mask that was introduced in 1916. This design had a mask connected by a hose to a tin can containing gas absorbent materials. It was an improvement on the earlier gas hoods and gave better protection against the different gases in use. Gas first was used in the Middle Eastern theatre by the British in April 1917 during the Second Battle of Gaza.); by National Army Museum ; out of copyright.