William Fletcher Barrett
Sir William Fletcher Barrett (1844-1925), Professor of Experimental Physics at the Royal College of Science, Dublin
1844 February 10th. Born in Kingston, 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 his sister; the social reformer Rosa Mary Barrett.
1848 The family returned to their native England in Royston, Hertfordshire.
1855 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 Dun 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.
1882 He discovered the shortening of nickel through magnetisation
When Barrett developed cataracts in his later years, he also began to study biology with a series of experiments designed to locate and successfully analyse 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.
1912 He was knighted
1916 He married Florence Willey
1925 May 26th. Died
1925 Obituary 
SIR WILLIAM F. BARRETT, F.R.S., died on the 26th May, 1925, in his 82nd year, and in him physical science has lost a devoted adherent and worker.
He received his early education at the Old Trafford Grammar School, Manchester, and in 1863, when only 19 years of age, became assistant to the late Prof. Tyndall, Professor of Natural Philosophy in the Laboratories of the Royal Institution. Under this great master of science he must have received much stimulation of his natural taste of acquiring and increasing his scientific, knowledge.
His chief life's work was in connection with the Chair of Physics at the Royal College of Science, Dublin, which position he filled with much distinction for no less than 37 years, that is until 1908. He carried out his work there with great success, training many students of note.
In 1899 he was elected a Fellow of the Royal Society and was knighted in 1912.
He was one of the founders of the Physical Society of London in 1874, and along with Guthrie was chiefly instrumental in organizing that body. He also collaborated with Guthrie in fostering the summer courses for science teachers which the Science and Art Department originated in 1871. These courses were probably the first attempt to introduce the systematic teaching of practical physics and were attended by teachers from all parts of the country. He was a prominent member of the Royal Dublin Society, to which body he communicated several important papers, as he did also to the Royal Society and to the Institution.
He was also a wellknown figure at many of the meetings of the British Association, to which body he contributed interesting papers, and served on several of its committees. After his retirement in 1908 from the Chair of Physics at the Royal College of Science, Dublin, he still maintained his interest in scientific matters, frequently attending meetings of the Royal Society and other bodies.
The writer has been asked to communicate this brief appreciation of Sir William Barrett's life work, no doubt on account of his personal association with Sir William whilst research work was being carried out between the years 1896 and 1902. Regarding this work, the writer can bear the fullest and most cordial testimony to the great interest, time, labour and skill shown by the deceased scientist. Sir William was greatly attracted by the work of Dr. G. Gore, F.R.S., who was probably the first to discover the peculiar behaviour of various specimens of iron which showed certain critical points during heating and cooling. This led him to make further investigations and to his discovery of the peculiar behaviour and property, now termed "recalescence," in steel. It was largely due to these results that methods of examining various types of steel, each more or less possessing its own idiosyncracies, by preparing heating and cooling curves, were established.
Between 1883 and 1902 the writer was discovering and developing his various new alloys of iron with other elements, and amongst other prominent scientists of those times, including engineers, electricians^ metallurgists, chemists and physicists, with whom he came in contact and discussed his numerous researches on alloys of iron with other elements, was Sir William, whose acquaintance he first made in 1887.
Sir William had a keen mind with a long and wide experience in carrying out experiments of a physical character, and he became intensely interested in the writer's many alloys of iron and carried out a large number of experiments on the magnetic, resistance, permeability and other electrical properties of the manganese steel discovered and made by the writer. These physical experiments and the results were described by Sir William in three papers to the British Association, and the Royal Dublin Society, read in 1886-9. Subsequently the writer supplied a large number of specially prepared small specimens of his various alloys of iron with carbon, chromium, nickel, tungsten, silicon, aluminium and other elements in order that Sir William might test them in a (similar manner. As a result, Sir William found that some of the alloys of iron and silicon^ also of iron and aluminium, possessed valuable magnetic and electrical characteristics, including their low-hysteresis and high-resistance qualities. The results of such tests were described at length in joint papers by Sir William, Mr. (now Professor) W. Brown (who had assisted at the experiments) and the present writer, read before the Royal Dublin Society in 1899, 1902 and 1904, and also before the Institution in 1902. The important practical results which some years later were obtained and their service in the development of electrical equipment are too well known to call for more detailed mention here, but afford a striking instance of the value of co-ordination of the work of investigators in different branches of scientific research.
Sir William was elected an Associate of the Institution in 1881 and a Member.in 1891. For several years he served on the Committee of the Irish Centre, of which he was chairman in 1901-02.