Evans, son of John Evans, a master in the Royal Navy, was born on 9 March 1815. He entered the navy as a second-class volunteer in 1828. After serving in and he was transferred in 1833 to, under Captain Richard Owen, and spent three years in surveying the coasts of Central America, the Demerara River, and the Bahama Banks. Evans subsequently served in the Mediterranean on board, the flagship of the Mediterranean Fleet, and then on,,,, and, passing through the different ranks of the ‘master's’ line, the officers then charged with the duties of navigation. In 1841 Evans was appointed master of, and for the next five years he was employed in surveying the Coral Sea, the Great Barrier Reef of Australia, and Torres Straits. Joseph Jukes, the geologist, was on board the Fly, and wrote an account of the expedition. After a short spell of duty in the Isle of Man, Evans returned, in 1847, in, under Admiral Stokes, to New Zealand, where he was engaged for four years in surveying the Middle and South Islands. During the Crimean War he served in the Baltic Sea, receiving the special thanks of Sir Charles Napier for his share in piloting the fleet through the Åland Islands. By this time Evans had become known for his scientific abilities, and in particular for his work on magnetism. He understood the need for studies of the effects of magnetic materials on ships' compasses at a period when the Navy was being revolutionised by the shift from wooden to iron construction. He had already done considerable work on this problem in the years between 1842 and 1851. In 1855 he was appointed superintendent of the compass department of the navy, and was able to devote himself entirely to the problems of the use of the magnetic compass in iron ships and armour-clads. Evans, in co-operation with Archibald Smith, accomplished the task satisfactorily. He contributed five papers, all dealing with the magnetism of ships, to the Philosophical Transactions of the Royal Society, of which he was elected a fellow in 1862. Evans was commissioned a staff-commander in 1863, staff-captain in 1867, and full captain in 1872. In 1865 he was appointed Chief Assistant to the Hydrographer to the Admiralty, Captain George Henry Richards, while continuing to tbe head of the magnetic department. In 1874 he succeeded Richards as Hydrographer, a post he held until 1884. In this position he was responsible for the charts, pilot guides and other publications of the Admiralty. He was invested as a Companion of the Order of the Bath, and promoted to Knight Commander of the Order of the Bath. He was vice-president of the Royal Geographical Society from 1879 to 1881, and president of the geographical section of the British Association in 1876. After resigning the post of hydrographer, Evans was appointed one of the British delegates to the International Meridian Conference held at Washington, D.C. in 1885, to fix a prime meridian and universal day. He died at his residence, 21 Dawson Place, Pembridge Square, London, on 20 December 1885. He had married, on 12 November 1846, Elizabeth Mary, eldest daughter of Captain Charles Hall, R.N., of Plymouth.
Published Work
Following the survey work in New Zealand in Acheron, and the subsequent work by Commander Byron Drury in, Richards and Evans published the 'New Zealand Pilot' in 1856. This went through a number of editions, the fourth appearing in 1875. In 1858 Evans prepared a ‘Chart of Curves of Equal Magnetic Variation,’ which was published by the Admiralty. In 1860 he wrote a valuable ‘Report on Compass Deviations in the Royal Navy’. This treated of the magnetic character of the various iron ships in the navy, and also of the, and was his first work to be published in the Philosophical Transactions of the Royal Society. His most important work was the ‘Admiralty Manual for Deviations of the Compass,’ of which Smith and himself were joint editors. A simple account of the same subject was issued by Evans in 1870 as an ‘Elementary Manual for Deviations of the Compass.’ These have become standard textbooks, having been translated and adopted by all the great maritime nations. His published work in the Philosophical Transactions of the Royal Society appeared between 1860-1872. Subsequently Evans devoted much attention to terrestrial magnetism. He compiled the magnetical instructions for the observers on board in 1872, and delivered a lecture on the ‘Magnetism of the Earth’ to the Royal Geographical Society in 1878. In 1881 he contributed a paper to the British Association on ‘Oceanic or Maritime Discovery from 1831 to 1881.’
