5925404 Observing the barrage, 16 August 1917 (lantern slide) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: Observing the barrage, 16 August 1917. Lantern slide, World War One, Western Front (1914-1918), 1917. British and French artillery forward observation officers watch the opening bombardment during the Battle of Langemarck (16-18 August 1917). A British field telephonist assists them with the ranging in of the guns. Langemarck was the second Allied attack of the 3rd Battle of Ypres and the drive towards Passchendaele. During the battle, while both sides were hampered by the heavy rain, the French made substantial gains in particular and the British were able to take some ground, but German counterattacks forced them back. From a box of 73 lantern slides.); by National Army Museum .