5923019 ?Through gas and smoke, our troops advance to the final assault of Passchendaele Ridge?, 1917 (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: ?Through gas and smoke, our troops advance to the final assault of Passchendaele Ridge?, 1917. Photograph, World War One, Western Front (1914-1918), 1917. The Germans first used gas against the French during the capture of Neuve Chapelle in October 1914 when they fired shells containing a chemical irritant that caused violent fits of sneezing. In March 1915 they used a form of tear gas against the French at Nieuport, and the following month chlorine gas against the Canadians at Ypres. These early experiments were but a small taste of things to come and as the war progressed all sides developed ever more lethal gases including phosgene and mustard gas. From a collection of 101 stereoscopic photographs entitled ?The Great War?.); by National Army Museum .