Virtual Discovery #26 - Heliograph

In spite of its relatively simple concept, the heliograph in its modern form dates only to 1869. Sir Henry Christopher Mance, (6 September 1840 -- 21 April 1926) was a British electrical engineer .He received a knighthood for developing the heliograph. Sir Henryjoined the Persian Gulf Telegraph Department in 1863, and was employed on the laying of the first Persian Gulf submarine communications cable. An inventive man, he was responsible for a number of important developments in the field of cable laying, testing and usage.In 1869 he invented the heliograph, a wireless solar telegraph that signals by flashes of sunlight using Morse code reflected by a mirror. The flashes were produced by momentarily pivoting the mirror. Frustrated by Government lack of interest, he sent a number of his instruments to Lord Roberts for use during the Second Afghan War, where the practical value of the invention was realised. It was subsequently adopted by military service worldwide and was still being used in World War 2