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Sir Henry Christopher Mance (1840-1926)
1926 Obituary 
SIR HENRY CHRISTOPHER MANCE, C.I.E., LL.D., who died at Oxford on the 21st April, 1926, was born in 1840.
Educated privately, he joined the Persian Gulf Telegraph Department in 1863, and was employed on the laying of the first Persian Gulf submarine cable. Although one of the youngest of the expedition, he was selected for early promotion, and in 1879 was appointed electrician to the Department, which position he held until his retirement in 1885.
He was the author of "Mance's method" for testing the internal resistances of batteries, communicated to the Royal Society in 1871 by Lord Kelvin, then Sir William Thomson; also the author of "Mance's method" for eliminating the effects of polarization and earth currents when testing cables having partial earth faults; this led to important economies in cable repairs. He further communicated various papers published in the Proceedings of the Society of Telegraph Engineers, on "A Method of Duplex Working," "The Respective Merits and Durability of Gutta Percha and India-rubber Joints," and "The Relative Susceptibility of Gutta Perch and Indiarubber to Attacks from the Teredo.”
He also designed a "system of automatic translation suitable for unstable relays," which system was adopted in connection with the Persian Gulf cables.
He was the first to publish a description of the remarkable light-circles phenomenon seen at rare intervals in the vicinity of the Persian Gulf, the light circles passing over the surface of the sea at the rate of 100 miles an hour. Mance's most noteworthy contribution to scientific development was the invention of the heliograph in 1869 at the age of 29. By a curious coincidence the idea first occurred to him on the coast of Baluchistan, where, over 2 000 years before, Alexander the Great had signalled to his armies from the neighbouring hills by means of the sun's rays reflected from his shield. As has occurred before, the Government were slow to realize the value of the new invention, and it was thanks to the initiative of Mance, who sent a number of his instruments to Lord Roberts for use during the second Afghan War, that the practical value of the invention was strikingly demonstrated, with the result that it has since been adopted in every military service, and has incidentally been made famous by Kipling in one of his "Departmental Ditties."
Sir Henry Mance joined the Society of Telegraph Engineers as an Associate in 1873, and became a Member in 1877. He was a Member of Council in 1890, a Vice-President from 1892 to 1896, and President of the Institution of Electrical Engineers in 1897. He was also a member of the Institution of Civil Engineers and the Physical Society.
After his retirement from the service of the Indian Government, Sir Henry continued to interest himself in electrical subjects. He was chairman of the Oxford Electric Co. from its foundation. He was on the Boards of the Electric Construction Co., Davis and Timmins, Ltd., and the West African Telegraph Co., and a member of the Provincial Electric Supply Committee of the United Kingdom.
Sir Henry was fond of sport of all kinds, a good shot, a lover of music, with a good voice, and a reciter of no mean order, and possessed a fund of personal experiences which made him a never-failing source of interest to his friends. Endowed with an essentially human and sympathetic disposition, he never spared himself to help a friend in need. He was practically blind for the last 10 years of his life. Undaunted, he stuck to his work and kept himself in touch with developments in spite of the effort of memory needed. He learned to read Braille after the age of 70. He was created C.I.E. in 1883 and Knight Bachelor in 1885, and was awarded the degree of Hon. LL.D., Aberdeen, in 1903. He married in 1874, and leaves a widow, three sons and two daughters.