Archer, William (1827–97), naturalist and librarian, was born 6 May 1827 (some sources have 1830), the eldest son of Richard Archer (1796?–1849), perpetual curate of Maghera hamlet, Co. Down, and his wife, Jane Matilda (née Campbell). Nothing is known of his education, though his two younger brothers attended TCD. It appears that he became estranged from his family, as he is not mentioned by Swanzy, who does mention his brothers as second and third sons in Richard Archer's family. William Archer moved (c.1846) to Dublin, where for many years he pursued a business career. He achieved fame as a naturalist, founding with others, in 1849, the Dublin Microscopical Club, of which he was the secretary and moving spirit for many years, and publishing many papers on Irish fauna and flora. He was elected MRIA (10 January 1870) and FRS (1875), on which occasion it was stated that he had ‘a knowledge of the minute freshwater organisms unparalleled among British naturalists and perhaps not surpassed for any other country’.
Archer began a new career when he became librarian of the RDS in January 1877. The bulk of the society's library was being taken over by the state to form the National Library of Ireland; Archer became the chief librarian of the new institution and had the task of overseeing the changes. Most of the ideas put forward in his pamphlet, Suggestions as to public library buildings . . . with especial reference to the National Library of Ireland (Dublin, 1881), were used by Sir Thomas Deane (qv) in his design for its new building, which opened in August 1890. The adoption by Archer of the Dewey system of classification and the inception of a dictionary catalogue, both novel in his day, were to prove of lasting value to users of the library. He retired, in poor health, in 1895 and died, unmarried, at his home, 52 Lower Mount Street, Dublin, on 14 August 1897. Archer was a shy, modest man, who declined professorships at the Royal College of Science for Ireland and at TCD, and who was nominated for membership of the RIA and the Royal Society without his knowledge.