William Ellis (1828-1916) was born at Greenwich on 20 February 1828. He joined the Royal Observatory in 1841, where he was employed on reducing lunar observations before switching to observational work. After working as Observer at the University Observatory, Durham, 1852-1853, he returned to the Royal Observatory as a permanent member of staff. He took charge of the Chronometric and Galvanic Department in 1856, and became Superintendent of the Magnetical and Meteorological Department in 1875. He retired in 1893, and died on 13 December 1916.