Photograph from collection of 41 lantern slides, collected between 1907-1911, by Lt H R S Massy, Royal Artillery, attached to the Northern Nigeria Regiment, West African Frontier Force.

A soldier of the Northern Nigeria Regiment signalling with a heliograph, a device that used Morse code flashes of sunlight reflected by a mirror to send messages. The flashes were produced by momentarily pivoting the mirror, or by interrupting the beam.