5921800 A Vickers machine gun team in gas masks, 1916 circa (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: A Vickers machine gun team in gas masks, 1916 circa. Photograph, World War One, Western Front (1914-1918), 1916. The machine-gun was one of the dominant weapons on the First World War battlefield. When established in a fixed defensive position and sited specifically to cover potential enemy attack routes it was a fearsome weapon. Infantry assaults upon such positions invariably resulted in high casualties. From an album of 22 official photographs.); by National Army Museum ; out of copyright.