Russian soldier using a periscope rifle, First World War, 1914-1918, (c1920). 'Taking the Enemy's Range with a Hyposcope: a masked Russian officer at his trench-post'. A hyposcope was a periscope sighting rifle attachment, enabling the shooter to remain hidden below cover. The device was developed in response to trench warfare conditions. From "The Great World War - A History" Volume IV, edited by Frank A Mumby. [The Gresham Publishing Company Ltd, London, c1920]