signaling

The "mirror and disc" apparatus at the right is a 5" Mance heliograph. The heliograph was used to signal by Morse code using flashes of reflected sunlight created by tilting the mirror intermittently. This one is set up in the "duplex" (twin mirror) arrangement. The duplex configuration was used when the sun was on the opposite side of the signaller from the target. The leather carrying case dangling below the tripod by the shoulder strap was use to carry the parts atop the tripod for travel, and the tripod itself was slung over the shoulder by the strap attached to the left leg of the tripod, with the cylindrical cap at the end of the sling holding the legs of the tripod together. The disc dangling just above the case is a protective cap (with female threads) that protected the male threads atop the tripod. As noted at left, the heliograph saw little use during the trench warfare on the Western front in WWI, but rather more so in the mobile warfare towards the end. Another photograph of heliographs in use on the western front is this one at the Imperial War Museum: www.iwm.org.uk/collections/item/object/205072698 .For more information on heliographs, see the Wikipedia article on heliographs and its references.

British troops operating from Nordia Hotel building overlooking Jaffa Road and Barclays Bank, showing heliograph operator signaling to troops on Tower of David, Jerusalem, Palestine - circa 1938

I believe this photo is related to this incident, which would time this at April, 1914: en.wikipedia.org/wiki/United_States_occupation_of_Veracruz

Good photo Boa foto Bună fotografie Hình ảnh tốt Gutes Foto Dobrá fotografie Bella foto Хорошие фото

bior: Yes, agreed! Thanks for the information. We will expand the caption information for this image, and add a date as well.

Kodaksights: Dobre zdjęcie / Dobra fotografia ! - in Polish ;)

Great photo - Wrong caption. The buildings in background do not match Veracruz ca. 1914. USS Chester attacked Naval academy early morning (8-9 am) on 22 April 1914. One of the men seems to be looking for planes. There were no planes flying over Veracruz on that date.