Hackett, Felix Edward (1882–1970), physicist, was born 15 August 1882 in Omagh, Co. Tyrone, second son among five sons and three daughters of Daniel Hackett and Jeanie Hackett (née Walsh). He was a student at UCD, and edited the college review, St Stephen's (1902–3). At this time the international scientific community was divided over the question of the existence of ‘N-rays’; Hackett was one of the supporters of the French scientist Blondlot, who claimed to have discovered the new form of radiation, and in 1904 the Scientific Transactions of the RDS published a paper by Hackett on the photometry of N-rays. The rays and their discoverer were very soon discredited, largely by German physicists; Hackett's scientific confidence might have suffered but his career did not, and in 1905 he was appointed a junior fellow of the RUI. He worked (1905–7) on radioactivity with J. A. McClelland (qv), and in 1908 studied at Johns Hopkins University, Baltimore, where he was awarded a Ph.D. He returned to Ireland (1909) as a physics lecturer in QCG, and in 1910 was appointed to a lectureship in the Royal College of Science; in 1921 he became professor of physics. From 1922 to 1924 he was dean of the college. In 1926, when the Royal College of Science was amalgamated with UCD, he was made professor of physics and electrical engineering there, and remained in UCD till his retirement (1952). Early in his career he published a number of papers on topics such as the absorption of radium rays by matter, and was founding chairman of the Irish branch of the Institute of Physics in 1964, but his main contribution to Irish life was in the service of the RIA and RDS; he was elected to the Academy in 1907, and held the office of treasurer for an unequalled length of time (1930–62). Hackett was one of the men who rallied to the support of the RIA in February 1922, when opponents were trying to form a National Academy of Ireland (Dámh Ioldánach Éireann) to supersede it. He was treasurer (1933), secretary (1933–53), and president (1953–6) of the RDS, and a member of the RDS executive committee (1936–70). Particularly interested in the development of Irish crafts and local industries, he was a member of the Homespun Society and a founder member of Country Markets. He was also a very enthusiastic founder member of An Óige (and its president 1944–68), and was president of the Library Association of Ireland (1943–9).
Hackett died at his home in Zion Rd, Rathgar, on 11 December 1970, and was buried in Dean's Grange. His wife Mary, who belonged to a prominent Omagh family, predeceased him on 6 October 1968. Her father was George D. Murnaghan (qv) MP, and the judge James A. Murnaghan (qv) was her brother; one of her brothers married one of her husband's sisters. Felix and Mary Hackett had no children.