A noted physicist, born in Dublin; served in artillery in 1803, maintained his connection with it till his retirement in 1874 as general, but owes his celebrity to his important investigations into the nature of terrestrial magnetism; accompanied as a scientist Boss and Parry in their search for the North-West Passage (1819-20); was President both of the Royal Society from 1861 to 1879 and of the British Association in 1853 (1788-1883).