Sir William Fletcher Barrett (10 February 1844 in Kingston, Jamaica – 26 May 1925) was an English physicist and parapsychologist. Life He was born in Jamaica where his father, William Garland Barrett, who was an amateur naturalist, Congregationalist minister and a member of the London Missionary Society, ran a station for saving African slaves. There he lived with his mother, Martha Barrett, née Fletcher, and a brother and sister. The family returned to their native England in Royston, Hertfordshire in 1848 where another sister, the social reformer Rosa Mary Barrett was born. In 1855 they moved to Manchester and Barrett was then educated at Old Trafford Grammar School. Barrett then took chemistry and physics at the Royal College of Chemistry and then became the science master at the London International College (1867–9) before becoming assistant to John Tyndall at the Royal Institution (1863–1866). He then taught at the Royal School of Naval Architecture. In 1873 he became Professor of Experimental Physics at the Royal College of Science for Ireland. From the early 1880s he lived with his mother, sister, and two live-in servants in a residence at Kingstown (now Dún Laoghaire). Barrett discovered Stalloy (see Permalloy), a silicon-iron alloy used in electrical engineering and also did a lot of work on sensitive flames and their uses in acoustic demonstrations. During his studies of metals and their properties, Barrett worked with W. Brown and R. A. Hadfield. He also discovered the shortening of nickel through magnetisation in 1882. When Barrett developed cataracts in his later years, he also began to study biology with a series of experiments designed to locate and successfully analyze causative agents within the eyes. The result of these experiments was a machine called the entoptiscope. He was elected a Fellow of the Royal Society in June 1899 and was also a fellow of the Royal Society of Edinburgh and the Royal Dublin Society. He was knighted in 1912. He married Florence Willey in 1916. He died at home, 31 Devonshire Place in London. Barrett's last book, Christian Science: An Examination of the Religion of Health was completed and published after his death in 1926 by his sister Rosa M. Barrett. Psychical research Barrett became interested in the paranormal in the 1860s after having an experience with mesmerism. Barrett believed that he had been witness to thought transference and by the 1870s he was investigating poltergeists. In September