Lieutenant-Colonel Jarvis in a trench with a periscope, Gallipoli, 1915

Photograph, World War One, Gallipoli (1915).

Periscopes provided a less dangerous way of observing the Turks from the trenches. In its simplest form, a periscope could be just a stick with two angled pieces of mirror at the top and bottom.

From a scrapbook containing 143 photographs, 1901 (c)-1940 (c).