1ª Guerra Mundial. The Lifeguard Periscope. F. Duerr & Sons. Manchester S.W. WWI
The periscope was invented and patented by Edgar Duerr, a second-generation family member. For use in trench warfare, the collapsible periscope was considered such a significant part of Britain’s war effort that originals used by troops are on display in The Imperial War Museums in London and Manchester, in addition to The Guards Museum in London.
The life-saving instrument enabled front-line soldiers to observe enemy movements from 50cm (20 inches) below the parapet, providing them with a view of up to 91m (100 yards).
Approved by the War Office and sold to individuals, the pocket-sized periscope weighed (20oz) and measured 11.5 x 11.5 x 5 cm (4.5 x 4.5 x 2inches) when closed.Screen Shot 2014-04-03 at 17.44.51
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