5926926 Signallers of the Cape Mounted Police, South Africa, 1900 circa (b/w photo) by Unknown photographer, (20th century); National Army Museum, London; (add.info.: Signallers of the Cape Mounted Police, South Africa, 1900 circa. Photograph, Boer War, 1900 circa. The soldiers are equipped with signal flags, telescopes and heliographs. This heliograph uses a mirror to reflect sunlight to a distant observer. By moving the mirror, flashes of light could be used to send Morse code. It was an ideal tool in the vast open spaces of South Africa as it allowed long distance communication without a fixed infrastructure.); by National Army Museum .