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A History of the Physics Department

The Physics Department - Some Historical Notes

Royal College of Science The Royal College of Science, built in 1906, housed the Chemistry  & Physics Departments. From 1906 to 1932 Callender was head of  the Physics Dept. He was famous for his work on the properties of  steam.        

G P Thomson replaced Callender in 1932. Thomson was a Nobel Laureate for his discovery of electron diffraction by crystals (and other substances) which meant that the electron’s motion could be described by the mathematics of wave mechanics. His father, J J Thomson, was also a Nobel Laureate for work on electrons as particles where the motion could (in the circumstances of his investigations) be described by Newtonian mechanics .    

G P Thomson, during his Physics Dept. headship, initially established an electron diffraction group. Subsequently he became involved in other spheres particularly nuclear energy after the German discovery of the production of neutrons in uranium (U235) related to the fission process. Later he became interested in the nuclear fusion process and in 1946, with M. Blackman, took out a patent for a fusion  machine. 

G P Thomson

G P Thomson was (until he retired, to become master of Corpus Christi College,  Cambridge) virtually the only Professor in the Physics Dept. He arranged to do work on  uranium to investigate the

Throughout his leadership of the Physics Dept. his interest in electron diffraction continued. possible neutron chain reaction. This was in the  early 1940s, but subsequently this was stopped and the work on uranium became  secret and  it ended at Imperial College.

The RCS building was outwardly symmetrical, with the Chemistry side (towards Exhibition Road) and the Physics side (towards Queens Gate). The building stood on the south side of the Imperial Institute Road – an ordinary through-road for traffic between Queens Gate and Exhibition Road. The Imperial Institute building faced the north side of the RCS building with what is now known as the Queens Tower facing the entrance of the RCS building. The Imperial Institute Building was also symmetrical about the Queens Tower with two smaller towers at each end of the building. The Imperial Institute was a museum demonstrating various aspects of the Empire. There was a free cinema together with other amenities. There was (and probably still is) a tunnel running from the vicinity of the Queens Tower to College’s Beit Building between Kensington Gore and Prince Consort Road. The tunnel emerged somewhere in the vicinity of the ground on which the new Physics building was to be erected as a first class steel frame building. The tunnel was very useful to avoid the rain. 

Imperial College The new Physics building was started sometime in the  1950s coinciding with P. M. S. Blackett arriving as the new  head of the Physics Dept. around 1953. Physics continued  in the new “old” RCS building till the completion of the new  Physics building in 1960 when removal from the old RCS  building to the new Physics building took place. The new  Physics building subsequently became the Blackett  Laboratory. 

 Blackett (Cambridge, Birkbeck, Manchester and finally  Imperial) instituted a professor in charge of each group. This meant a change from a single overall professor to perhaps around 8 “new” professors. He was instrumental in ensuring the provision of a “common room” on level 8 of the new building as well as having a say in the design of other parts of the new Physics building.

He was involved with the Wilson Labour Government as scientific advisor. He was awarded the OM (presumably on the advice of Harold Wilson). After Blackett’s death Wilson gave a memorial lecture for him in the large physics lecture room in the new building, 1975. During Blackett’s time at Imperial he became President of the Royal Society and his final accolade was a Life Peerage.

Blackett Blackett’s handling of the Staff Meetings was unique for its brevity. He spent the last years of his retirement working on magnetism in the in the Dept. He had a long interest in terrestial magnetism linked, in some way, with continental drift.

 After Blackett’s retirement from the Departmental headship he was replaced by Butler,  the first of the system of rotating “heads” each one for a period of about 5 years. The  Rector effectively appointed each new head.  

 During the 1930s Richard Beeching was first an undergraduate under GP Thomson    and was awarded his PhD in 1936. After a brief time as a demonstrator, Beeching left  to eventually obtain a high place with ICI. The Conservative government 1963  persuaded him to improve the condition of the railway. As a result about 20% of the  system was shut  down. He later became a life peer.

Written by Dr N D Lisgarten

The Story of Physics in South Kensington

By Harold Allan

The story of Physics in South Kensington begins in 1872 when a government – sponsored body revelling in the name “Metropolitan School of Science applied to Mining and the Arts” decided to move its operations from cramped quarters off Oxford Street to Exhibition Road in South Kensington. Here there was land, purchased using profits from the Great Exhibition of 1851 and made available to museums and colleges for development. Here too was an empty building large enough to meet the School's immediate needs. This building – whose design has been described (with very good reason) as “curious” – was originally intended to house a school of Naval Architecture that eventually moved to Greenwich instead. So Physics, together with Chemistry and other fledgling departments including Natural History and Geology, moved in. The future Imperial College was here in embryo. The building, which still stands today as the Henry Cole wing of the Victoria and Albert Museum, was soon named the Huxley building in honour of Thomas Henry Huxley, the eminent Victorian palaeontologist and the College's most famous Dean. Among the students was H. G. Wells (1883-1887), the future novelist, science fiction writer and Fabian socialist. In his autobiography Wells expresses a high opinion of Huxley as teacher but a less than flattering view of the physics professor, Frederick Guthrie. He recalls being required to construct a mercury in glass barometer, given a bottle of mercury glass tubing and a Bunsen burner. His efforts were unsuccessful, the only fact remaining in his memory being that the hot glass can still burn the fingers after it has ceased to glow.

When Imperial College was created by Royal Charter in 1907 the pure science departments, including Physics, became grouped into one constituent college, the Royal College of Science. The other constituent colleges were the City and Guilds College (for engineering) and the Royal School of Mines. In the same year a magnificent new building – labelled the R.C.S building – was opened in Imperial Institute Road to provide much needed additional accommodation, especially laboratories for Chemistry and Physics. This building, purpose built for the use to which it was to be put, gave excellent service right up to 1960. It also served as a home to the Science Museum Library. Despite the move into the new building, Physics did not lose all links with the Huxley building, which became the home of the Mathematics department. So physics students had to make regular 10 minute pilgrimages there for their maths lectures – though it may be doubted if the spirits of Huxley or Wells could inspire them in that strange dark atmosphere.

An illuminating account of life as a physics student shortly after the opening of the new R.C.S building is contained in a letter written in 1982 by a retired schoolmaster H. H. Grainger of St. Olave's Grammar School in South London. He was one of a class of 13 at the R.C.S. in the years 1907-1910. Among the staff he recalls Professor H. L. Callendar (famous for thermodynamics and the properties of steam - pictured on right), A. Fowler (astrophysics) and the Hon. R. J. Strutt – later Lord Rayleigh (radioactivity). W. Watson, nicknamed “Mercury Bill”, was largely responsible for the new laboratory teaching arrangements and wrote two pioneering undergraduate textbooks (sadly he died in 1919 after working on defence from poison gas during WWI).

Mr Grainger makes it clear how much tougher student life was then than it is today. There were no common room facilities at all and the only opportunity for buying refreshments was at a tin shanty standing in some open ground now covered by the Science Museum. Here a pot of tea and Bread and Butter could be bought for 4d. Money being, of course, short, Mr Grainger was glad to take work every Saturday at the Natural History Museum cleaning and tabulating fossils. The pay was 1/- per hour. At least, he recalls, what he earned from this work was very helpful for the Geology exam in the BSc finals!

RCS For the present writer the R.C.S. building evokes vivid memories from more recent years. It was, like other Edwardian public buildings, built to impress. Stone steps led up to an imposing entrance door guarded in early post-1945 years by “Wally”, an old soldier and veteran of the Boer War (when given a reasonable pretext, Wally was always ready to display his war wounds). Since the public evidently found it difficult to distinguish the R.C.S. building from a South Kensington museum, Wally had a blackboard on display with a chalk-written message “The building is NOT a museum” – to which the students were prone to add the ambiguous addendum “but we have a fine collection of fossils”. The steps were the locations for the annual photograph of the Mathematical and Physical Society members, including all of the staff and students of the two departments.

Inside the building there was space for Physics in one wing and Chemistry in the other (deciding on which way to turn in the entrance was not difficult, all that was needed was a sense of smell). The provision of lecture theatres, teaching laboratories, research rooms etc. was still more than adequate in the 1950s as doubtless it had been in 1907. Indeed the large physics lecture theatre continued to receive special mention in the College Calendar because of its vibration free lecture demonstration bench plus water, gas and electricity services. But the vogue for lecture demonstrations was fast fading in post war years as hands-on experience in the teaching laboratories took over. With changes to the physics courses a new (“third years”) practical class was introduced, devised principally by Dr C. E. Wyn-Williams, a one-time colleague of Rutherford and pioneer of circuit design for electrical counting.

The building had its oddities. It seems there was originally an air-conditioning system with ducting built into the walls, but this was not functioning in later years. The corridors had supplementary hot-water radiators fed from a Ministry of Works unit shared by all the local museums. So the corridors were heated but not the rooms. As a further complications the Ministry of Works heating was switched on and off, in the best Civil Service manner, according to the calendar date rather than the outside temperature.

Down in the basement there was a “constant temperature room” with double walls, much sought after by spectroscopists. But the space between the walls turned out to be an excellent hiding place, and it was here that the R.C.S. student union kept their mascot “Theta” (an outsized model thermometer). Acquiring other union's mascots was once a popular sport and security was important! One hears less of such romps these days – perhaps loyalty to the greater unity, Imperial College, now takes precedence over loyalty to one's constituent college? However, not long ago, during WWII, I knew a man who had worked in the physics department under the Nobel Prize winner Sir George Thomson in the 1930s who always referred to his time in the R.C.S., not Imperial.

Blackett The physics department's final move (so far) came in 1960, as part of the massive expansion of Imperial College that took place as part of the then gov ernment's “white-hot technological revolution”. A new 12-storey building went up at the corner of Prince Consort Road and Queens Gate, large enough to accommodate a student intake of 200 per year, plus a wide range of specialist research groups. The man who provided the initiative and drive for this move was the Head of Department, Nobel Prize winner P. M. S. Blackett (later Lord Blackett and President of the Royal Society). Blackett's foresight and planning set the department on a course that has made possible the spectacular achievements in so many research groups from his time to the present. It is in deed appropriate that the laboratory should be known as the Blackett Laboratory.

Common Room

A small but significant mark of Blackett's wisdom was the incorporation of a spacious common room within the Blackett Laboratory. Here physicists from all the distinct research groups can meet and discuss their problems over coffee or come together in the evening for a joint celebration. By sharing this common facility the members of the laboratory really do become part of one community. This makes not merely for happiness but for better physics. Without a doubt our predecessors H. G. Wells and H. H. Grainger would have approved.

Past Heads of Department

HoDS R Hunt

G G Stokes

J Tyndall

F Guthrie

Sir Arthur Rücker

H L Callender

Sir George Thomson

P M S Blackett

C C Butler

P T Matthews

D J Bradley

I Butterworth

T W B Kibble

D M Blow

D J Southwood

B L Morgan

J B Pendry

P L Knight

D Bradley

J Haigh

J Nash


Nobel Prize Winners

Patrick Blackett Nobel Prize Certificate Patrick Blackett was awarded the Nobel Prize in 1948 for "his development of the Wolson cloud-chamber and his discoveries therewith in the fields of nuclear physics and cosmic radiation".

Blackett started his research career in the '20s with Rutherford who had discovered the transmutation of nitrogen to oxygen. Blackett used the Wilson cloud-chamber to observe 400,000 tracks of alpha-particles in nitrogen gas and saw 8 clear examples of nitrogen to oxygen transmutations. With the Occhialini he then used the chamber to detect cosmic rays. initially the chamber was simply expanded every few seconds with the result that most photographs were blank; Blackett realised that by putting Geiger counters above and below the chamber to control its operation, photographs could be taken only when cosmic rays had left tracks in the gas. In 1933 he used the technique to confirm Anderson's discovery of the positron, clearly demonstrating that positrons were produced in electron-positron pairs.

In 1953 he took over the Physics Department here, planning and leading its major expansion in the 1950s. Subsequently he became president of the Royal Society, was made a life-peer and a Companion of Honour, and was honoured with the Order of Merit.

Abdus Salam Nobel Prize Certificate Professor Abdus Salam is one of the foremost theoretical physicists of his generation. Born in Jhang (now in Pakistan) in 1926, he had a brilliant career as a student in Lahore and Cambridge and made an immediate impact on the world of physics with his pioneering studies in quantum field theory. He came to Imperial College in 1957 to found the Theoretical Physics Group, which rapidly became a leading centre for research. His best known work on the unified theory of weak and electromagnetic interactions, won him a Nobel Prize in 1979, shared with Professors Sheldon Glashow and Steven Weinberg of Harvard.

Professor Salam has played a major role in the development of scientific research in the third world. He was the founder and first Director of the International Centre for Theoretical Physics in Trieste, which has been served to keep many physicists from developing countries in touch with the leading edge of international research. He also inspired the foundation of the Third World Academy and became its first President. Throughout his career, he has had a deep concern for the wider social implications of science, in which he has written extensively. He has become and inspiration to a whole generation of scientist in the United Kingdom, in Pakistan and throughout the Third World.

George Thomson Nobel Prize Certificate Sir George Thomson, Head of the Physics Department, Imperial College from 1930 to 1952 received the Nobel Prize in 1937 for his demonstration in 1927 of the wave nature of electrons by their diffraction in passing through thin films of metals. It has been said that his father J.J. Thomson, had received his Nobel Prize for showing that electrons were particles, G.P. (as he was generally known) received his for showing that they were waves! His contributions to science were, however very much broader, launching the work in nuclear physics at I.C., playing an important role in guiding wartime work on nuclear energy and nuclear weapons and initiation work on methods for controlled fusion, first at I.C. and later at Aldermaston.

In 1952 he returned to Cambridge as Master of Corpus Christi where he was valued for his energetic support of many developments and urbanity and range of his table talk. Those who remember him at Imperial recall his interest in every aspect of the department's work, extending to his regular vetting of designs for apparatus in the workshop and his encouragement of all research staff to take tea for a well-defined twenty minutes in the old lecture theatre.


Interview with Professor Brian Morgan

Dr Tariq Ali, Director of the Energy & Environment Office and former pupil of Prof Morgan, interviews Brian Morgan about his time spent in the Physics deparment as a student and later as head of department. Prof Morgan recalls how Imperial College has changed over the years as well as some of the notable characters that he worked and studied with in the past.

Interview with Professor Brian Morgan

Dr Tariq Ali, Director of the Energy & Environment Office and former pupil of Prof Morgan, interviews Brian Morgan about his time spent in the Physics department as a student and later as head of department.

Professor Blackett Lecture

“Blackett as Scientific Leader: Physics, War and Politics in the Twentieth Century” full text speech: Mary Jo Nye, Oregon State University, at Imperial College, 26 January 2005

Ladies and gentlemen, friends and colleagues, it is a privilege and a pleasure to speak before you today about one of the distinguished scientists of this institution, Patrick Maynard Stuart Blackett, for whom the Blackett Laboratory is named. I am grateful to the Department of Physics, especially Professor Sir Peter Knight and Dr. Martin McCall, for hosting my visit along with the Harvard University Press, especially Ann Sexsmith and Fiona Wyatt. I also would like to say how pleased I am to thank publicly Patrick Blackett's daughter Giovanna Bloor for her generous help and friendship as I have been writing my book on Blackett's scientific life and work. One of the great surprises when I embarked upon this book was that Blackett had not been the subject of a recent biography. The reason for this lapse is most likely the commanding presence of the excellent book-length biographical obituary written by Sir Bernard Lovell in 1975 for the Royal Society. My own biography is different, but certainly not better. We have available now, too, a centenary volume of essays on Blackett edited by Captain Peter Hore of the Royal Navy, following symposia marking Blackett's birth in 1897.

Some time ago Giovanna Bloor asked me what drew my interest to her father. The simplest answer to this question is that my work as a historian has concentrated on the history of the modern physical sciences, and Blackett is one of the most important experimental physicists of the twentieth century. However, that simple answer still begs the question.

Two aspects of Blackett's career captured my attention originally. One is the elegance of the narrative history of Blackett's bold hypothesis in 1947 that the Earth's magnetic field can be explained in a simple fundamental equation, having to do with the Earth's rotating mass, and Blackett's own subsequent disproof of his hypothesis using an improved magnetometer of his own design. This scientific case-history has the ethical character of one of Aesop's fables and the philosophical virtue of supporting Karl Popper's demarcation of science from non-science on the basis of falsifiable hypotheses. What appeared to be Blackett's failure in proving his hypothesis alsoo turned out to be the pathway to Blackett's and other scientists' revolutionary studies of rock magnetism and evidence for the old hypothesis of continental drift. I talked about this aspect of Blackett's work at the Blackett symposium here at Imperial College in April 1998.

The reason for my writing a full-scale biographical study of Blackett is broader in scope. I was struck by the controversial life that Blackett, the physicist, chose to lead in war and politics. This is the Blackett who was said by The Times at his death in 1974 to have been a “Radical Nobel-Prize Winning Physicist” who had been “committed too far to the left for [even] a Labour Government to employ with ease.”  While many regarded Blackett as a hero for his achievements as a British physicist and his wartime role in operational research, others vilified him for his postwar criticism of British wartime and Cold War military strategy.

In this criticism Blackett publicly questioned the Allied wartime bombing of civilian urban centers, and he denounced postwar discussions of the tactics of mass destruction as a normal operation of war. Blackett became the first person to openly argue that the United States had used the atomic bomb in Japan "not so much as the last military act of the Second World War, as the first act of the cold diplomatic war with Russia."  Outraged Americans characterized Blackett's statements and his opposition to their development of atomic weapons as a Stalinist apology full of political prejudices. George Orwell in 1949 included Blackett on a blacklist of thirty-eight crypto-communists or fellow-travellers that Orwell drew up for the British Foreign Office.

Blackett's politics were leftwing, rooted in Fabian socialism. He was part of the Soho dining group in the 1930 called Tots and Quots, which included the scientists Solly Zuckerman, Desmond Bernal, Julian Huxley, Joseph Needham, C. H. Waddington, C. D. Darlington and Lancelot Hogben, and the science journalists J. G. Crowther and Peter Ritchie Calder.  By the late 1950s some of this group were meeting at the Reform Club or Brown's Hotel with Hugh Gaitskell, Harold Wilson, Dick Crossman, and other members of the Labour opposition. In his politics, as in his studies of physics or of the operations of war, Blackett demonstrated absolute confidence in the power of rational scientific thinking to solve problems. He made misjudgements and mistakes, of course, and he was too sanguine, or ill-informed, about the bloody politics internal to the Soviet Union, but he displayed stubborn courage in choosing to expose himself to public debate while still pursuing an active scientific life of research, teaching, and administration.

What, we might ask, were some of the historical circumstances that drove Patrick Blackett into the scientific and political life that he chose? What were the personal characteristics that enabled him to achieve a status that his friend, the geophysicist, Teddy Bullard described as that of “the most versatile physicist of his generation”? Finally, what were Blackett's own notions of leadership, and how did he become one of the most powerful scientific figures of his generation? In what follows, I will briefly review aspects of Blackett's education and career, and then comment on ways in which he was perceived by his contemporaries. I finally will turn to the theme of scientific leadership, with remarks about some other scientists whom Blackett admired, concluding with observations on the character and significance of Blackett's role as a scientific leader in the twentieth century.

Building Character, Learning the Trade

Patrick Blackett arrived at Cambridge and the Cavendish Laboratory in 1919, and he arrived in uniform. Born in London, Blackett was a middle child with two accomplished sisters. He remembered his childhood as one “brought up in the kindly security of an Edwardian middle-class home.”  It was a home in which overt affection was not shown, and children were not praised, “lest they became conceited.”  As a boy, Blackett spent a good deal of time constructing wireless sets and model aeroplanes. Just before his thirteenth birthday, in September 1910, he entered Osborne Naval College, joining an elite group that included the future King George VI.

At that time, in 1910, admission to Osborne was ranked at the prestige of a Winchester scholarship, and the naval schools probably provided the best science and engineering education available in any secondary school in Britain.  In addition to exercises in laboratories, all cadets were expected to learn the rudiments of using tools in pattern-making, fitting, and turning and forging. They operated lath es and engaged in metal filing, as well as in carpentry. Mathematics and modern languages were well taught, as was naval history.

Leadership was regarded as a natural attribute of character. Admission boards were explicit about the qualities they sought:

What is the right sort of boy? . . . that boy has the best chance [who] is resourceful, resolute, quick to decide, and ready to act on his decision. He must be no slacker, but keen to work and play. He should be sound alike in wind and limb, and in the big and little principles of conduct . . . . He should give promise of being responsive and observant, closely in touch with his surroundings, but master of himself. The boy of sensitive, poetic spirit, the ruminating young philosopher, the scholar whose whole heart [is] in his books are types that have a real use in the world, but their proper place is not the Navy.

In some sporting activities, Blackett was not as successful as other boys. Captain Lord Alastair Graham later read to Blackett from notes that he had made on Blackett as a cadet: “Games: does not shine.” Still, part of Navy lore is that Blackett was kicking off at a students' football match when he was informed of winning the Nobel Prize.  As a naval cadet at Dartmouth, Blackett enjoyed sailing in the Estuary. He was an avid birdwatcher, and he took photographs with a camera that he built himself, a prelude to cloud-chamber photographs that would later make him world famous as a physicist.

On August 1 st , 1914, when war broke out, 400 cadets at Dartmouth were told to pack their chests. Blackett saw action in the Falklands in 1914 and at Jutland in 1916. He witnessed the battle cruiser HMS QUEEN MARY sink, and thousands drown. His own battleship HMS BARHAM took fire in the battle, with twenty-four deaths on board. As First Lieutenant controlling gunnery fire on HMS Sturgeon , Blackett's last action was a destroyer battle off Terschelling (Netherlands) in April 1918. He was in charge of controlling shell damages to the ship and getting it back to Harwich. He managed to get off some 50 rounds of gunnery shots as well.

When the war was over in November 1918, the Admiralty decided to send some 400 junior officers to a six-month course of general studies at Cambridge University. Still in uniform, Blackett dined for the first time at Magdalene College in late January 1919. A few days later, he wandered into the Cavendish Laboratory. Three weeks later he resigned from the Navy. By May 1921 he received his degree, with a Second Class in the Mathematics Tripos and a First in Part II of the Physics Tripos.  He was one of the few physicists of his generation to have served and survived combat in the war before completing his university studies. He was unusual among fellow university science graduates in his self-discipline, self-reliance, and experience of leadership.

Ivor Richards, a young philosophy don at Magdalene College, and later professor of literature at Harvard, recalled first meeting Blackett in 1920.

I was living . . . in a garret in Free School Lane a door or two from Cavendish Laboratory. 'Came a quick step on its ‘rotten-runged, rat-riddled stair,' a tap on the door, and there entered a young Oedipus. Tall, slim, beautifully balanced and looking always better dressed than anyone. People used to ask him the name of his tailor . . . . [Above] was that mysterious intense and haunted visage, which later made [Jacob] Epstein count this Nobel Prize winner's bust among his greatest . . . .

Many descriptions of Blackett as physicist remark on his appearance, including his height at six feet two and one-half inches. Some commentators remark that his looks were somewhat misleading. “Tall and strikingly handsome . . . he might have been predominantly formidable. But he was not. Besides being humane, he was witty, amusing and very good company.”  Of Blackett in his 40s, a former student recalled “He was tall and strikingly handsome.”  Of Blackett in his 50s, the French newspaper France Soir suggested he could have been a cinema star. Of Blackett in his 60s, at Imperial College in London, a friend wrote: “Even more handsome as an aging man than as a young one, he was as much a figure in the King's Road, as he had once been in the King's Parade.”

In March 1924 Blackett married Costanza Bayon, a student of modern languages at Newnham College. She had an Italian father, but had been raised by an English couple in Rome who nicknamed her “Pat.”  Thus, to intimate friends, they were the two Pats. During the 1924-1925 academic year, they lived in Göttingen, where Blackett worked with James Franck in electron physics.  Returning to Cambridge, the couple settled at 59 Bateman Street, where they kept open house at least once a week. Reports were that their guests tended to be semi-bohemian and left-wing. Ivor Richards called them the “handsomest, gayest, happiest pair in Cambridge.”

From 1921 to 1933, Rutherford was Blackett's first and only research director. Assigned by Rutherford in 1921 to modify an automatic cloud chamber for the study of alpha particles bombarding targets, Blackett worked for several years to perfect the instrument in the face of Rutherford's impatience for results.  Rutherford had assigned Blackett the problem of confirming Rutherford's hypothesis that alpha particles incident upon nitrogen gas induce a transformation in the nitrogen nucleus, with expulsion of a hydrogen particle (proton) from the nucleus. In the summer of 1924, Blackett obtained eights tracks confirming rearrangement in a nucleus. These photographs have been widely reprinted ever since.  The work made Blackett's reputation at the age of twenty-seven.

Blackett's second set of really famous experi ments came in the early 1930s when he collaborated with Giuseppe Occhialini on devising a cloud chamber in which expansion of the cloud chamber is triggered by pas sage of charged particles in cosmic radiation. While the two were accumulating data and discussing its theoretical implications with Paul Dirac in fall 1932, C arl Anderson at Caltech announced his discovery of a positively charged electron in the cosmic radiation. Anderson initially characterized the particle's production as a rare event. In contrast, Blackett and Occhialini used their data to explicitly link the anti-electron to Dirac's relativistic electrodynamics, a theoretical insight that had not occurred to Anderson.

Although Blackett and Occhialini were nominated immediately for a Nobel Prize for their work, it was Anderson who received a share of the Nobel Prize in Physics in 1936 for his “discovery of the positron,” along with Viktor Hess who had established the existence of cosmic radiation. No doubt, Blackett and Occhialin i were disappointed in this outcome. Blackett also was chagrined by Rutherford's cool response to the positron work when Rutherford told Blackett that he would prefer to see the positron particle produced in radioactivity transformations rather than in cosmic radiations.

1933 turned out to be a pivotal year. When Rutherford told Blackett that he thought Blackett should spend more time teaching and that he, Rutherford, had no intention to expand facilities for nuclear physics at the Cavendish, Blackett left Rutherford's office white-faced with rage. Outside the door, Blackett told his postgraduate research student Frank Champollion that “If physics laboratories have to be run dictatorially . . . I would rather be my own dictator.”

Blackett often was asked about the Cavendish years and about the legendary Rutherford. Blackett praised Rutherford's power of concentration and pictorial imagination, his eye for the unexpected, and his boundless enthusiasm, saying that he, Blackett, had “learnt early [from Rutherford] the vital importance of the role of the director of research in selecting promising problems for his research students.”  This would be Blackett's method, too, for directing a research school.

A Lab of His Own

In 1933, Blackett left the Cavendish Laboratory for Birkbeck College in London, where he took charge of the physics department and laboratory. In 1937 he succeeded Lawrence Bragg in the physics chair at Manchester, a position which previously had been held by Rutherford. And, of course, Blackett would return to London in 1954, to Imperial College, taking many of his Manchester laboratory colleagues with him. Shortly after he arrived in London, in 1933, Blackett was recruited by Henry Tizard, in early 1935, to join an Air Ministry committee charged with investigating the use of radio waves in air defense. Although many members of the British Left were taking strongly pacifist positions in the mid-1930s, Blackett parted company with them in this matter. He was no pacifist. By 1940 Blackett became scientific adviser to the Army's anti-aircraft command, organizing a group of scientists to study the operational use of radar sets, guns, and mechanical calculators for anti-aircraft fire. [Edward Bruce] Hamley's classic nineteenth-century textbook The Operations of War (1867) would be updated now by methods of scientific analysis.

In the Royal Air Force's Coastal Command, Blackett headed a group that recalculated depth settings for anti-submarine explosives. Moving to the Admiralty in 1942, Blackett directed an operational research group that brought about significant improvement in the use of airborne radar for finding German submarines which were sinking merchant ships in the Atlantic. This work often is credited as a turning point in the war, by summer of 1943, so that American supplies and troops could reach England for the invasion of Europe.  It was this work, too, that brought Blackett into what later became a well-known confrontation with Prime Minister Churchill's scientific advisor Frederick Lindemann and that laid the basis for Blackett's public critique in 1948 of the wholesale bombings of German cities as both inefficacious and immoral.

Taking on increased university and governmental duties after the war, Blackett remained active both in personal research and in directing the physics department at Manchester. He continued to be “hands-on,” showing young Clifford Butler, for example, how to set up the cloud-chamber control mechanism for cosmic-ray experiments at Manchester. He closely followed Butler and George Rochester's experiments that photographed tracks of a new “strange” particle identified by its signature V-track, and Blackett worked with them in writing up the results on what later would be called kaons, although his name did not appear on the published paper.

The military experiences of his youth and his maturity deeply informed Blackett's style of leadership in his laboratories. Images of military bearing and conduct frequently have been used to characterize Blackett: his very presence was said to carry authority. At Manchester, a former student reports that he “was awestruck by [Blackett's] stately procession down the main stairs for lunch. He always walked in the dead centre of the staircase, disdaining the banisters. He held his hands, naval fashion, in his jacket pockets, with thumbs protruding. He had no nickname: he was Professor Blackett.” In an interview with Brian Connell of Anglia Television, Blackett admitted that his laboratory staffs said that he ran a department like a Captain runs a ship: “ There is something I think in the tradition of delegating authority completely to young, junior people and then if things go wrong, taking the blame yourself.” That this style of leadership had a practical effect in research, as well as in management, is noted by Francis Everitt, one of Blackett's postgraduate students at Imperial in the late 1950s. Everitt did his thesis work on rock magnetism and reversals of magnetic polarity in sedimentary and igneous rocks. Two remarks encapsulate Blackett's outlook, says Everitt: “Make sure you gather plenty of data,” and “You should treat your research like a military campaign.”

Everitt himself came to Imperial College as an undergraduate and stayed on for his postgraduate degree. It was precisely because of Blackett's failed experiments on the Earth's magnetism that Everitt wanted to study with Blackett, by his own account. As I mentioned earlier, Blackett's most spectacular failure was his disproof, using his own magnetometer, of his well-publicized hypothesis that the magnetic fields of the sun, stars, and earth are a fundamental property of their rotating mass. A beautifully simple law had related magnetic and angular momentum to the gravitational constant and the speed of light. But the law was wrong, as proven by Blackett and his assistants from 1949 to 1952. Yet Blackett's announcement that experiments had proved his rotating body hypothesis wrong only increased his prestige. Everitt recalls:

By the time I was seventeen, I had heard of Blackett, initially because of the famous cloud chamber photographs on nuclear disintegrations which were reproduced in dozens of books. My physics master in high school . . ., when he was teaching us about magnetism, . . . described Blackett's hypothesis and then explained how, when the evidence told against it, Blackett had demonstrated his scientific integrity by immediately acknowledging that it was wrong. Thus Blackett was held up as a high role model of the physicist by a man who did not in the least share Blackett's political views.

Blackett's personal research at Imperial College had turned to rock magnetism and the use of paleomagnetic data to establish latitude effects for continental drift.

His rock magnetism group included John Clegg from Manchester; and Blackett also brought with him to Imperial other Manchester colleagues and technicians, including Harry Elliot, with a cosmic-ray group, and Clifford Butler, who headed the high-energy nuclear physics group.

When Blackett arrived at Imperial, there were three chairs in the department: Blackett's; David Wright's chair in Technical Optics, and Samuel Devons's Chair in Low-Energy Nuclear Physics. Devons went on to succeed Blackett at Manchester in 1955. By 1960 Imperial had a new Physics building, seven professors, 27 lecturers, and 32 research assistants in the department, divided into ten independent research groups. Students numbered some 300 undergraduates and 100 postgraduates.

As Bernard Lovell has noted, Blackett was one of the first department heads in Great Britain to implement the strategy of multi-professorial departments, aiming to create an urban scientific research and educational institution that equalled the old universities of Cambridge and Oxford, while opening up opportunities for new disciplinary fields and for college students unlikely to enter the older elite establishments. This was a practical application of Blackett's socialist and scientific politics. The commitment led him in the early 1950s to decline to be a candidate for the Cavendish Laboratory directorship, succeeding Lawrence Bragg, or for the Provostship at King's College in Cambridge. The Imperial Physics Department initially had one Nobel laureate in Bl ackett himself. Dennis Gabor, who became Professor of Applied Electron Physics in 1958, received the Nobel Prize in 1971; and Abdus Salam, who became Professor of Theoretical Physics in 1959, after transferring from the Mathematics Department, shared the 1979 Nobel Prize with Sheldon Glasgow and Steven Weinberg.

It is not surprising that Everitt found Blackett to be one of the busiest men he had ever seen in the late 1950s: chairing Royal Society, university, and government committees; a member of Harold Wilson's inner circle of advisers on science and technology policy; a consultant to the Indian government on science and military matters. As a close friend of the Cambridge-educated Indian physicist Homi Bhabha, Blackett also began spending considerable time in India after 1947, where the geophysics group from Imperial set up a paleomagnetic survey of the Indian subcontinent with Indian scientists in the Tata Institute in Bombay. Blackett also became a military and scientific advisor to the Indian.

Construction of the Blackett Lab

 Here is a photo casebook of the construction of the Blackett Lab, started in 1959 and completed in 1961.

Harold Allan and Norman Lisgarten remember

harold allan and norman lisgarten remember/

Two former members of the Physics Department are interviewed