Boxwood military surveying board, 1890 (c)

The army fought to establish the British Empire, but it was also important in understanding and mapping it. Its soldiers explored and surveyed its diverse territories. But surveying was not easy work and, in about 1880, the military sketching or surveying board was introduced as an aid to map-making.

It was devised by Colonel W H Richards, a topographical instructor at the Royal Military College Sandhurst. It was intended to be used while riding - a leather strap attaches it to the wrist.

Boards were fitted with a compass and a clinometer, to measure the angle of slope. Brass rollers on the sides held the paper steady: as a sketch map was completed, these could be twisted to reveal more paper.