William Henry Bragg

William Henry Bragg
William Henry Bragg
Born	2 July 1862(1862-07-02) Wigton, Cumberland, England
Died	10 March 1942 (aged 79) London, England
Nationality	United Kingdom
Institutions	University of Adelaide University of Leeds University College London Royal Institution
Alma mater	Cambridge University
Doctoral advisor	J. J. Thomson
Doctoral students	W. L. Bragg Kathleen Lonsdale William Thomas Astbury
Known for	X-ray diffraction
Notable awards	Nobel Prize in Physics (1915)
Religious stance	Christian
Notes He is the father of William Lawrence Bragg; as there was no Ph.D. program at Cambridge until 1919, J. J. Thomson was actually his Master's advisor.

Sir William Henry Bragg OM, KBE (2 July 1862 – 10 March 1942) was a British physicist and chemist who uniquely shared the Nobel Prize in Physics with his son, William Lawrence Bragg, in 1915.

Biography

Early life

Bragg was born at Westward near Wigton, Cumberland, the son of Robert John Bragg, a merchant navy officer and farmer, and his wife Mary Wood, a clergyman's daughter. At seven years of age his mother died and he was raised by an uncle, also William Bragg at Market Harborough, Leicestershire. He was educated at King William's College, Isle of Man, and, winning a scholarship, Trinity College, Cambridge. He graduated in 1884 as third wrangler in the mathematical tripos.^[1][2]

University of Adelaide

In 1885 Bragg was appointed "Elder Professor of Pure and Applied Mathematics, who shall also give instruction in Physics"^[2] at the University of Adelaide in Australia and started work there early in 1886. At that time he had little knowledge of physics, but there were only about a hundred students doing full courses at Adelaide of whom scarcely more than a handful belonged to the science school. As a result Bragg was able to develop his knowledge of physics in his early years, but it was not until he was past 40 that he began to do research work of note. At the meeting of the Australasian Association for the Advancement of Science, held at Dunedin in 1904, Bragg, as president of his section, delivered an address on "Some Recent Advances in the Theory of the Ionization of Gases". This paper was the origin of his first book Studies in Radioactivity (1912). Soon after the delivery of his 1904 address some radium bromide was made available to Bragg which he was able to experiment with. In December 1904 a paper by him "On the Absorption of a Rays and on the Classification of the a Rays from Radium" appeared in the Philosophical Magazine, and in the same issue a paper "On the Ionization Curves of Radium", written in collaboration with R. Kleeman, also appeared. At the end of 1908 Bragg resigned his professorship at Adelaide. During Bragg's 23 years in Australia he had seen the number of students at the University of Adelaide almost quadruple, and had a full share in the development of its excellent science school.^[1]

Whilst in South Australia Bragg contributed to the development of the sport of lacrosse, being a founding member of the North Adelaide and Adelaide University Lacrosse Clubs.^[2] In 1962 The Bragg Laboratories were constructed at The University of Adelaide to commemorate 100 years since the birth of Sir William H Bragg.^[1]

University of Leeds

Bragg became Cavendish Professor of Physics in 1909 at University of Leeds. He continued his work on X-rays with much success. He invented the X-ray spectrometer and with his son, William Lawrence Bragg, founded the new science of X-ray analysis of crystal structure. In 1915 father and son were jointly awarded the Nobel Prize in Physics for their studies, using the X-ray spectrometer, of X-ray spectra, X-ray diffraction, and of crystal structure. Their volume, X-Rays and Crystal Structure (1915), had reached a fifth edition 10 years later.^[1]

University College London

Bragg was appointed Quain Professor of physics at University College London in 1915 but did not take up his duties there until after World War I. He did much work for the government at this time, largely connected with submarine detection, at Aberdour on Forth and at Harwich, and returned to London in 1918 as consultant to the admiralty. While Quain professor at London he continued his work on crystal analysis.^[1]

Royal Institution

From 1923 he was Fullerian professor of chemistry at the Royal Institution and director of the Davy Faraday Research Laboratory. This institution was practically rebuilt in 1929-30 and under Bragg's directorship many valuable papers were issued from the laboratory.^[1]

Legacy

He became a Fellow of the Royal Society in 1907, was elected a vice-president in 1920, and served as president of the society from 1935 to 1940. Ernest Rutherford discussed his theories on the proton and nucleus with Bragg, who disagreed with him.

The lecture theatre of King William's College is named in his memory. One of the School 'Houses' at Robert Smyth School, Market Harborough, Leicester is named 'Bragg' in his memory as a former student of the school. Since 1992 the Australian Institute of Physics has awarded the Gold Medal for Excellence in Physics to commemorate Sir Lawrence Bragg (in front on the medal) and his father Sir William Bragg for the best PhD thesis by a student at an Australian University.^[3]

In 1889, he married Gwendoline Todd, daughter of Sir Charles Todd, who died in 1929. He was survived by a daughter and his son, Sir William Lawrence Bragg, another son died at Gallipoli^[2]. Bragg was created C.B.E. in 1917, K.B.E. in 1920, and in 1931 was given the Order of Merit.^[1]

Timeline

• University of Adelaide (1886-1908)
• University of Leeds (1909-15)
• University College London (1915-23)
• Royal Institution

Prizes

• Nobel Prize (1915)
• Matteucci Medal (1915)
• Rumford Medal (1916)
• Copley Medal (1930)

Publications

• William Henry Bragg, The World of Sound (1920)
• William Henry Bragg, The Crystalline State - The Romanes Lecture for 1925. Oxford, 1925.
• William Henry Bragg, Concerning the Nature of Things (1925)
• William Henry Bragg, Old Trades and New Knowledge (1926)
• William Henry Bragg, An Introduction to Crystal Analysis (1928)
• William Henry Bragg, The Universe of Light (1933)

References

External links

• Data from the University of Leeds
• Fullerian Professorships