William Henry Bragg

Early life and education The Old Grammar School, Market Harborough, which has a plaque inside noting Bragg's attendance.

William Henry Bragg was born on 2 July 1862 in Westward, Cumberland, England, the son of Robert John Bragg, a merchant marine officer and farmer, and Mary Wood, a clergyman's daughter. His mother died when he was age 7, and was raised by his uncle (also named William Bragg) in Market Harborough. He was educated at the Grammar School there, at King William's College on the Isle of Man, and—having won an exhibition—at Trinity College, Cambridge. He graduated in 1884 as third Wrangler, and in 1885 earned First Class Honours in the mathematical Tripos.

Career and research University of Adelaide In 1885, Bragg was appointed Elder Professor of Mathematics and Physics at the University of Adelaide in Australia, and started work there in early 1886. Being a skilled mathematician, at that time he had limited knowledge of physics, most of which was in the form of applied mathematics he had learnt at Trinity College. Also at that time, there were only about a hundred students doing full courses at Adelaide, of whom less than a handful belonged to the science school, whose deficient teaching facilities he improved by apprenticing himself to a firm of instrument makers. He was an able and popular lecturer; he encouraged the formation of the student union, and the attendance, free of charge, of science teachers at his lectures. At the University, the tube was attached to an induction coil and a battery borrowed from Sir Charles Todd, Bragg's father-in-law. The induction coil was utilised to produce the electric spark necessary for Bragg and Barbour to "generate short bursts of X-rays". The audience was favorably impressed. He availed himself as a test subject, in the manner of Röntgen and allowed an X-ray photograph to be taken of his hand. The image of the fingers in his hand revealed "an old injury to one of his fingers sustained when using the turnip chopping machine on his father's farm in Cumbria".

As early as 1895, Bragg was working on wireless telegraphy, though public lectures and demonstrations focussed on his X-ray research which would later lead to his Nobel Prize. In a hurried visit by Rutherford, he was reported as working on a Hertzian oscillator. There were many common practical threads to the two technologies and he was ably assisted in the laboratory by Arthur Lionel Rogers who manufactured much of the equipment. On 21 September 1897 Bragg gave the first recorded public demonstration of the working of wireless telegraphy in Australia during a lecture meeting at the University of Adelaide as part of the Public Teachers' Union conference. Bragg departed Adelaide in December 1897, and spent all of 1898 on a 12-month leave of absence, touring Great Britain and Europe and during this time visited Marconi and inspected his wireless facilities. He returned to Adelaide in early March 1899, and already on 13 May 1899, Bragg and his father-in-law, Sir Charles Todd, were conducting preliminary tests of wireless telegraphy with a transmitter at the Observatory and a receiver on the South Road (about 200 metres). Experiments continued throughout the southern winter of 1899 and the range was progressively extended to Henley Beach. In September the work was extended to two way transmissions with the addition of a second induction coil loaned by Mr. James Oddie of Ballarat. It was desired to extend the experiments cross a sea path and Todd was interested in connecting Cape Spencer and Althorpe Island, but local costs were considered prohibitive while the charges for patented equipment from the Marconi Company were exorbitant. At the same time Bragg's interests were leaning towards X-rays and practical work in wireless in South Australia was largely dormant for the next decade.

The turning-point in Bragg's career came in 1904 when he gave the presidential address to section A of the Australasian Association for the Advancement of Science in Dunedin, New Zealand,

There is a bust of Bragg in North Terrace, Adelaide, South Australia.

University of Leeds Commemorative plaque on the Parkinson Building, University of Leeds.

From 1909 to 1915, Bragg was Cavendish Professor of Physics at the University of Leeds. He continued his work on X-rays with much success. He invented the X-ray spectrometer and with his son, Lawrence, then a research student at Cambridge, founded the new science of X-ray crystallography, the analysis of crystal structure using X-ray diffraction.

World War I Both of his sons, Lawrence and Robert, were called into the army after the First World War broke out in 1914 . The following year, Bragg was appointed Quain Professor of Physics at University College London. This institution was practically rebuilt in 1929–1930 and, under Bragg's directorship, many valuable papers were issued from the laboratory.

Royal Society and World War II In 1935, Bragg was elected President of the Royal Society. The physiologist A. V. Hill was biological secretary and soon A. C. G. Egerton became physical secretary. During World War I, all three had stood by for frustrating months before their skills were employed for the war effort. Now the cause of science was strengthened by the report of a high-level Army committee on lessons learned in the last war; their first recommendation was to "keep abreast of modern scientific developments". Anticipating another war, the Ministry of Labour was persuaded to accept Hill as a consultant on scientific manpower. The Royal Society compiled a register of qualified men. They proposed a small committee on science to advise the Committee on Imperial Defence, but this was rejected. Finally in 1940, as his term ended, a scientific advisory committee to the War Cabinet was appointed. He was among the 2,300 names of prominent persons listed on the Nazis' Black Book, of those who were to be arrested on the invasion of Great Britain and turned over to the Gestapo.

Personal life and death In 1889, in Adelaide, Bragg married Gwendoline Todd, a skilled water-colour painter and the daughter of astronomer Charles Todd.

Bragg died of heart failure on 12 March 1942 in London at the age of 79. 1939 National Academy of Sciences International Member 1940 American Philosophical Society International Member Awards Year Organisation Award Citation 1915 Accademia dei XL Matteucci Medal — 1915 Royal Swedish Academy of Sciences Nobel Prize in Physics "For their services in the analysis of crystal structure by means of X-rays." 1916 Royal Society Rumford Medal "On the ground of his researches in X-ray radiation." 1930 Royal Society Copley Medal "For his distinguished contributions to crystallography and radioactivity." 1930 Franklin Institute Franklin Medal "For the development of method of determining molecular and crystal structure by reflection of X-rays." 1936 Institution of Electrical Engineers Faraday Medal — 1939 National Academy of Sciences John J. Carty Award for the Advancement of Science —

Chivalry Year Head of state Title/Order 1920 George V Knight Commander of the Order of the British Empire 1931 George V Order of Merit

Commemoration The Electoral district of Bragg in the South Australian House of Assembly was created in 1970, and was named after both William and Lawrence Bragg. Bragg crater on the Moon was named in his honour in 1970.

The lecture theatre of King William's College (KWC) is named in memory of Bragg; the Sixth-Form invitational literary debating society at KWC, the Bragg Society, is also named in his memory. One of the school "Houses" at Robert Smyth School, Market Harborough, Leicester, is named "Bragg" in memory of him being a student there. Since 1992, the Australian Institute of Physics has awarded the Bragg Gold Medal for excellence in physics for the best Ph.D. thesis by a student at an Australian university. The two sides of the medal contain the images of Sir William Henry and his son Sir Lawrence Bragg.

The Experimental Technique Centre at Brunel University is named the Bragg Building. The Sir William Henry Bragg Building at the University of Leeds opened in 2021.

In 1962, the Bragg Laboratories were constructed at the University of Adelaide to commemorate 100 years since the birth of Sir William H. Bragg. also in Adelaide, Australia was completed in late 2023. It is named for both father and son and offers radiation therapy for cancer patients.

In August 2013, Bragg's relative, the broadcaster Melvyn Bragg, presented a BBC Radio 4 programme "Bragg on the Braggs" on the 1915 Nobel Prize in Physics winners.

Publications William Henry Bragg, William Lawrence Bragg, "X Rays and Crystal Structure", G. Bell & Son, London, 1915. 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)