In 1885,[8] Bragg was appointed Elder Professor of Mathematics and Physics at theUniversity of Adelaide[9] in Australia, and started work there in early 1886.[10] 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.[6][7]
Bragg's interest in physics developed, particularly in the field ofelectromagnetism. In 1895, he was visited byErnest Rutherford, en route from New Zealand to Cambridge; this was the commencement of a lifelong friendship. He had a keen interest in the new discovery of X-rays byWilhelm Röntgen. On 29 May 1896 at Adelaide, he demonstrated before a meeting of local doctors the application of "X-rays to reveal structures that were otherwise invisible".Samuel Barbour, senior chemist ofF. H. Faulding & Co., an Adelaide pharmaceutical manufacturer, supplied the necessary apparatus in the form of aCrookes tube, a glass discharge tube. The tube had been obtained at Leeds, England, where Barbour visited the firm ofReynolds and Branson, a manufacturer of photographic and laboratory equipment. Barbour returned to Adelaide in April 1896. Barbour had conducted his own experiments shortly after return to Australia, but results were limited due to limited battery power.[11] At the University, the tube was attached to an induction coil and a battery borrowed from SirCharles Todd, Bragg's father-in-law. Theinduction coil was utilised to produce theelectric 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 inCumbria".[12][13]
As early as 1895, Bragg was working onwireless 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.[14][15] Bragg departed Adelaide in December 1897,[16] 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.[16][17] He returned to Adelaide in early March 1899,[18] 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).[19] 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. Oddie of Ballarat.[20] 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 theMarconi 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 theAustralasian Association for the Advancement of Science inDunedin, New Zealand,[7] on "Some Recent Advances in the Theory of the Ionization of Gases". This idea was followed up "in a brilliant series of researches"[7] which, within three years, earned him a fellowship of theRoyal Society of London. This paper was also the origin of his first bookStudies in Radioactivity (1912). Soon after the delivery of his 1904 address, someradium bromide was made available to Bragg for experimentation. In December 1904 his paper "On the Absorption of α Rays and on the Classification of the α Rays from Radium" appeared in thePhilosophical Magazine, and in the same issue a paper "On the Ionization Curves of Radium", written in collaboration with his studentRichard Kleeman, also appeared.[6][7]
At the end of 1908, Bragg returned to England. During his 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."[6] He had returned to England on the maiden voyage of theSSWaratah, a ship which vanished at sea on its second voyage the next year. He had been alarmed at the ship's tendency to list during his voyage, and had concluded that the ship'smetacentre was just below hercentre of gravity. In 1911, he testified his belief that theWaratah was unstable at the Inquiry into the ship's disappearance.[21]
Both of his sons, Lawrence and Robert, were called into the army after theFirst World War broke out in 1914 .[23] The following year, Bragg was appointedQuain Professor of Physics atUniversity College London.[6] He had to wait for almost a year to contribute to the war effort; in July 1915, he was appointed to theBoard of Invention and Research set up by the Admiralty.[6] In September, his younger son Robert died of wounds atGallipoli. In November, he shared theNobel Prize in Physics with Lawrence. The Navy was struggling to prevent sinkings by unseen, submergedU-boats. The scientists recommended that the best tactic was to listen for the submarines. The Navy had ahydrophone research establishment atAberdour, Scotland, staffed with navy men. In November 1915, two young physicists were added to its staff. Bowing to outside pressure to use science, in July 1916, the Admiralty appointed Bragg as scientific director at Aberdour, assisted by three additional young physicists. They developed an improved directional hydrophone, which finally convinced the Admiralty of their usefulness. Late in 1916, Bragg with his small group moved toHarwich, where the staff was enlarged and they had access to a submarine for tests. In France, where scientists had been mobilized since the beginning of the war, the physicistPaul Langevin made a major stride with echolocation, generating intense sound pulses with quartz sheets oscillated at high frequency, which were then used as microphones to listen for echoes. Quartz was usable whenvacuum tubes became available at the end of 1917 to amplify the faint signals. The British madesonar practicable by using mosaics of small quartz bits rather than slices from a large crystal. In January 1918, Bragg moved into the Admiralty as head of scientific research in the anti-submarine division. By war's end, British vessels were being equipped withsonar manned by trained listeners.
Inspired by Lawrence's methods for locating enemy guns bythe sound of their firing, the output from six microphones miles apart along the coast were recorded on moving photographic film.Sound ranging is much more accurate in the sea than in the turbulent atmosphere. They were able to localize the sites of distant explosions, which were used to obtain the precise positions of British warships and of minefields.
After the war, Bragg returned to University College London, where he continued to work on crystal analysis.[6]
In 1923, Bragg was appointedFullerian Professor of Chemistry at theRoyal Institution and Director of the Davy Faraday Research Laboratory.[24] This institution was practically rebuilt in 1929–1930 and, under Bragg's directorship, many valuable papers were issued from the laboratory.[6] In 1919, 1923, 1925, and 1931, he was invited to deliver theRoyal Institution Christmas Lecture onThe World of Sound;Concerning the Nature of Things,Old Trades and New Knowledge andThe Universe of Life respectively.[25]
In 1935, Bragg was electedPresident of the Royal Society.[26] The physiologistA. V. Hill was biological secretary and soon A. C. G. Egerton became physical secretary.[27] 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".[28] 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 theGestapo.
Bragg played tennis and golf, and as a founding member of theNorth Adelaide andAdelaide University lacrosse clubs, contributed to the introduction oflacrosse to South Australia. He was also the Secretary of the Adelaide University Chess Association.[29]
Bragg died of heart failure on 12 March 1942 inLondon at the age of 79.[4]
The lecture theatre ofKing 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, theAustralian Institute of Physics has awarded theBragg 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.[35]
The Experimental Technique Centre atBrunel University is named the Bragg Building. The Sir William Henry Bragg Building at theUniversity of Leeds opened in 2021.[36]
In 1962, the Bragg Laboratories were constructed at theUniversity of Adelaide to commemorate 100 years since the birth of Sir William H. Bragg.[6]
The Australian Bragg Centre for Proton Therapy and Research[37] 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 broadcasterMelvyn Bragg, presented a BBC Radio 4 programme "Bragg on the Braggs" on the 1915Nobel Prize in Physics winners.[38][39]
^This is still a unique accomplishment, because no other parent-child combination has yet shared a Nobel Prize (in any field). In several cases, a parent has won a Nobel Prize, and then years later, the child has won the Nobel Prize for separate research. An example of this is withMarie Curie and her daughterIrène Joliot-Curie, who are the only mother-daughter pair. Several father-son pairs have won two separate Nobel Prizes.
^Bragg Centenary, 1886–1986Archived 16 March 2022 at theWayback Machine, University of Adelaide, Pages 3 & 4. Proof of advertisement in the Oxford University Gazette of 16 October 1885, and the Cambridge University Reporter of 13 October 1885. The advertisements read:
THE UNIVERSITY OF ADELAIDE
ELDER PROFESSOR OF MATHEMATICS AND EXPERIMENTAL PHYSICS
The Council invite applications for the above Professorship. Salary £800 per annum. The appointment will be for a term of five years, subject to renewal at the discretion of the Council. Salary will date from March 1, 1886, and the Professor will be expected to enter on his duties on that date. An allowance will be made for travelling expenses. Applications with testimonials should reach ... not later than December 1, 1885.
Bragg was informed of his appointment by a letter dated 17 December 1885.
^George, Robert. (1996). 100 Years of X-Rays – the South Australian Connection. The Journal of the Radiology History & Heritage Charitable Trust. 12(Autumn/Winter): 3.
^Hall, Kersten T. (2014). The Man in the Monkeynut Coat: William Astbury and the Forgotten Road to the Double-Helix. Oxford University Press. Oxford. Page 26.
^"RETURN OF PROFESSOR BRAGG".Evening Journal. Vol. XXXI, no. 8817 (ONE O'CLOCK ed.). Adelaide. 6 March 1899. p. 2. Retrieved11 February 2018 – via National Library of Australia.
^"WIRELESS TELEGRAPHY".Evening Journal. Vol. XXXI, no. 8989 (ONE O'CLOCK ed.). Adelaide. 28 September 1899. p. 2. Retrieved11 February 2018 – via National Library of Australia.
"[a] most valuable record of his work and picture of his personality is the excellentobituary written by Professor Andrade of London University for the Royal Society of London." Statement made by SirKerr Grant, in:
"The Life and work of Sir William Bragg", the John Murtagh Macrossan Memorial Lecture for 1950, University of Queensland. Written and presented by Sir Kerr Grant, Emeritus Professor of Physics, University of Adelaide. Reproduced as pages 5–37 ofBragg Centenary, 1886–1986Archived 16 March 2022 at theWayback Machine, University of Adelaide.
"William and Lawrence Bragg, Father and Son: The Most Extraordinary Collaboration in Science", John Jenkin, Oxford University Press 2008.
Ross, John F.A History of Radio in South Australia 1897–1977 (J. F. Ross, 1978)[1]
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