1915, Photograph, PRG 280/1/12/9
Four soldiers demonstrating a tripod mounted signalling instrument described as being a heliograph. A researcher has suggested that this appears to be a Mance Mark V 5" heliograph configured in the 'duplex' (two-mirror) configuration used when the sun is behind the signaller. The leather carrying case, which was customarily draped around the legs of the tripod, is not visible.