Short and Simple (ish) Guide to X-ray Diffraction

  X-ray diffraction (or X-ray crystallography) was the chief physical method used to determine the structure of DNA. In this post, I will briefly and as simply as I can (which with my non-scientific background should not be a problem!) explain what x-ray diffraction technique is and its relative importance to the overall discovery.

What does X-ray diffraction actually mean?

 X-ray diffraction is the method of projecting a beam of X-ray radiation at a target object and through to a photographic film on the far side. A series of spots appear on the photographic film following this exposure, which is formed by the x-ray radiation diffracting off the structure that they passed through. These diffraction patterns give an indication of the general structure of the object (such as an inorganic crystal or macro- molecule such as DNA) which can then be delineated using complex mathematical formulas.

Why use X-rays in the first place?

The reason why X-ray beam is required in the first place is that atoms are too small (0.1nm between them, bearing in mind that 1 millimetre = 1000000 nanometres) to be revealed using visible light and therefore could not be viewed by a light microscope (even an electron microscope does not possess the required magnification). X-ray radiation fits the appropriate wavelength to be diffracted by the object and produce visible results.   

What causes the diffraction of the X-ray beams?

What the X-ray beam are diffracting is not the entire atom but the orbiting electrons (one of the component parts of an atom) that are close enough to the core (nucleus) of the atom to give a good indication of the structure of the unit cell (the term used for the repeating unit found in crystals and macromolecules). The end image is known as an electron density map of that unit cell. However due to the incredibly weak image a single molecule would produce, a crystalline structure is used instead, for example common salt (NaCl), since a crystalline structure provides a huge number of molecules arranged in the same orientation and therefore produces the same scattering effect on the X-ray beams. 

In this diagram, the diffraction of the X-ray beam causes an image with a helical arrangement to form as all the DNA molecules in a fibre are aligned in the same direction.

X-ray diffraction of nucleic acids at King’s College London from 1950 to 1953 

 X-ray diffraction studies on DNA began in June 1950 when Maurice Wilkins asked PhD student Raymond Gosling to assist him in diffracting the DNA fibre samples prepared by the Swiss biochemist, Rudolf Signer. Fibre diffraction did not usually provide good quality images because of the thinness of the fibres and therefore a very small mass to scatter the radiation. Nevertheless, the fibres’ remarkable uniformity when wetted allowed Wilkins to manipulate them into a bundle and mount them on a wire frame to obtain x-ray diffraction images. The initial images showed promise but Wilkins and Gosling were greatly assisted by J T Randall’s own experience with X-ray diffraction.  He advised how the surrounding air could affect the x-ray scattering. The solution was to pass hydrogen through the camera and control the relative humidity of the sample.  With this in place, the resulting images were much sharper and showed a clear crystalline diffraction pattern.

X-ray diffraction pattern obtained by M H F Wilkins and R Gosling in late 1950 showing a clear crystalline arrangement.

It was in late 1950 that the theoretical physicist Alec Stokes first noticed an interesting observation from the images. He realised that there was no diffraction at all along the length of the molecules: a sign that DNA might be helical.  However, the King’s College team needed far sharper images to confirm this hypothesis. This required a new X-ray camera that could work on single fibres.  Through a fortunate coincidence, Werner Ehrenberg and W E Spears had just developed one at Birkbeck: this was generously loaned to the King’s College team.

Before the new camera was set up, it was decided that Rosalind Franklin, who was joining the laboratory from Paris, would replace Wilkins in producing the x-ray diffraction images with the continued assistance of Raymond Gosling. Both Stokes and Wilkins continued working on the problem with the latter embarking on some rough tests with the old X-ray diffraction camera on various DNA specimens that produced an observed “X” crossed pattern. The X pattern of diffraction was created by the x-ray radiation scattering at right angles off the "zigzag" structure of the DNA chain.  This interpretation was further supported when Franklin and Gosling produced the first “B” structure X-ray patterns in the late summer of 1951. This was a crucial development as it showed two observed states of DNA: crystalline “A” and semi-crystalline “B” (the best B structure diffraction photograph became known as “Photo 51”). The photos also supported the predicted observed readings of a helix that Alec Stokes had developed using the mathematical technique known as Bessel functions.

Plot of Bessel Functions for a smooth helix, named "Waves at Bessel-on-sea" by Alec Stokes who completed the calculations for the diagram over a single train journey.

It was now Maurice Wilkins and Rosalind Franklin disagreed over the direction of the research in finding the overall structure. Wilkins was keen on hypothetical model building while Franklin favoured a more systematic study of the structure. This parting of ways can be partially explained as stemming from the limitations of the x-ray diffraction process itself. For example, the evidence from the photos clearly pointed to a helical structure but this begged question: what type of helix? Helices in nature could occur in single, double and even triple strands and there was no clear indication, which was the right number. This is why the King’s College London attempt at model building proved to be a failure when the model made by Bruce Fraser showed a triple helix based on the chemical readings but was unable to fit with the rest of the x-ray data. A crucial piece of the puzzle was missing and related closely to DNA’s function of providing the genetic material for life: it was only when Jim Watson and Francis Crick came up with the base pair hypothesis that the double helix seemed the ideal form. 

In this diagram, we can see the general similarity between a single and a double helix.

X-ray diffraction studies undertaken at King's College London provided part of the experimental structural data needed to solve the general structure of the DNA double helix. Yet, as important as these observations were other methods and disciplines were of equal importance in unravelling the overall structure, in particular the biochemical work of Erwin Chargaff and the biological insight of Jim Watson. X-ray diffraction work on DNA at King’s did not finish with the unveiling of the structure in March 1953 but continued for another decade as Wilkins and his team worked to test to the correctness of the "Watson-Crick" model. 

Campaign to declassify Porton Down laboratory

  In 1968, an intense public opposition to chemical and biological weapons existed in the United Kingdom. This state of affairs was created by public anger and opposition to their use by the American government in the Vietnam conflict. Members of the public and environmental and disarmament groups became increasingly suspicious of the microbiological research establishment (MRE) at Porton Down, which was suspected of producing nerve gas. A campaign began to declassify the MRE at Porton Down.

 The campaign starting point was on 18 July 1968 with Labour M.P. Tam Dalyell's parliamentary question: should the Porton laboratory be transferred from the Ministry of Defence to the Ministry of Health and its work be made declassified? Maurice Wilkins and fellow Nobel Prize winners Cecil F Powell and Fred Sanger wrote to Prime Minister Harold Wilson in support and followed it up by orchestrating a press-campaign involving fellow Nobel Prize winners and Royal Society Fellows.

Wilkins systematically wrote to his fellow scientists about the issue urging them to write to Wilson. He received replies from the likes of Dorothy Hodgkin, Max Perutz, Richard Synge, Conrad Waddington and Sir Lawrence Bragg.

a copy of the letter that Maurice Wilkins sent to his fellow scientists

 Some of those who responded declined to support the campaign, like his former biophysics department colleague, Dame Honor Fell. She, like many of those who declined, although sympathetic argued that the chemical and biological warfare research done by the microbiological research establishment had acted as a deterrent in the Second World War against potential German nerve gas attacks.

 However, the majority of scientists who were asked agreed to support the campaign and twenty-one fellows of the Royal Society, including eight Nobel Prize winners endorsed the campaign. The result of the press campaign and mounting student and public anger was an official open day of the facility announced by Wilson scheduled for the 23-25 October 1968. Maurice Wilkins was one of a number of scientists who were invited to attend and his archive retains a copy of the official brochure produced for the visit.

  Wilkins later recalled that “many scientists came on the Open Day and a more open-minded attitude to the work there seemed to be created. But we came away well aware that with weapons such as these it was difficult to tell what research was for offensive use, and what was defensive, aimed at protecting people from them”.




  Here at King’s College London we have several collections on the work carried out at Porton Down and chemical and biological warfare in the Liddell Hart Centre Military Archives. Our large collection entitled “Gassed: British Chemical Warfare Experiments on Humans at Porton Down” the background research material for a book of the same name by journalist Rob Evans, charts the development of chemical and biological warfare there, the human experiments carried out and interviews with former employees of the lab. Another collection, Bad trip to Edgewood,  provides information on research carried at Porton Down as well as extensive transcripts and notes on chemical and biological warfare research carried by the US Government from 1955 to 1975.

Radium Island: A short story by Maurice Wilkins, aged eleven

Sometimes when working in an archive it is possible to stumble upon items that are truly unexpected, such as ‘Radium Island’. This charming story by a schoolboy Maurice Wilkins (written circa 1928 when he was eleven years old) tells of the adventure of Hugh O'Brien and Ronald Chrisp as they try to escape 'Radium Island'. What makes Radium Island interesting is not only its prescient title, given Maurice Wilkins' later work on the atom bomb "Manhattan Project", but also the classically boyish obsession with comics, new technology and war. It predates the first of W E Johns’ ‘Biggles’ stories by around four years.

Title page of Radium Island: The short story was written in a school exercise book for Wlyde Green College, Birmingham, the school Wilkins attended when his family moved to Birmingham and was probably written in 1928 (according to the older Maurice's recollection when he would have been eleven). The "Plan" refers to a map of Radium Island that can see be seen below.

Map of Radium Island: This rather technical looking map of Radium Island could almost be mistaken for an authentic representation until you notice some of the captions such as "where the duel was fought" or "sign of the green dagger". However, if you were to try to find "Radium Island" using the longitude and latitude readings you would actually find the Cook Islands in the Pacific Ocean.

As the above map suggests Maurice Wilkins was quite a meticulous and technically adapt schoolboy. Already at this age he was creating model boats, cars and planes in his father's workshop inspired to some extent by the magazine The Modern Boy, with its reporting of powerful fast new machines like the one time like "world record breaking car Major Segrave's 1000 horsepower Sunbeam". This fascination with science and technology crops up throughout the story, including this oddly accurate geological description of the presence of radium:

"Chrisp was sitting looking blankly at the wall, when all of a sudden he sprang up and grabbed O'Brien by the shoulder and made him look at the shining vein of carnotite which yields radium situated in the opposite wall!"

For all non-geologists, carnotite is the mineral deposit that contains both uranium and radium ore. Who knew? Maurice Wilkins aged eleven.

Beginning of Radium Island where Chrisp and O'Brien are held captive by the natives on the island but discover Radium in their prison

Illustration of airplane: One of three drawings of airplanes in the story. Rather wonderfully, the text describes how he had bought the plane broken from an adventurer who had "bad luck with it" and reconstructed, then flew it, ran out petrol, crashed, was rescued, mended it again and then did not use it again for lack of petrol.

Maurice Wilkins and social responsibility in science: In his own words

In the previous post, I outlined some of the organisations that Maurice Wilkins was involved with that promoted social responsibility in science. In this post, I would like to cover Maurice Wilkins own thoughts on this subject and how they developed and changed in his lifetime.

“The Crisis in Science”

It was during the sixties that Maurice Wilkins entered the public debate regarding the value and implications of science and society. His 1962 Nobel Prize gave him the freedom and authority to “consider the wider role of science in life”. In his autobiography, he states how he found the global political situation made it increasingly difficult to continue his “quiet, steady biological work”.  His awareness of the risks posed by the Cold War and the dangers of weapons of mass destruction is evident in his opening address to the “Social Impact of Modern Biology” conference held at the Friend’s House, London in 1970:

 “The crisis in science today has not only direct bearing on the question of our survival but is of deep significance to our fundamental beliefs and at value judgements”

The newspaper, the "Journal American" reporting Maurice Wilkins' Nobel Prize award. Other news that day includes: an escalation in military tension between the US and the USSR over Cuba ( in what was later known as the Cuban Missile Crisis), US spacecraft Ranger 5 lifted off on its lunar mission while also in the news the first law suit over the prescription of thylidomide to pregnant mothers resulting in deformed children was also under way. 

Underlining this crisis was a fundamental change in scientific thought, as Wilkins went on to elaborate:

“Yet even [though] scientists continue to work undisturbed, their attitudes to their work have, since the war, significantly changed. Although many scientists regard their work unquestioningly, in general there has been a perceptible change. The main cause is probably the Bomb: scientists no longer have their almost arrogant confidence in the value of science. At the same time non-scientists openly question the value of science.”

He, like a significant number of his colleagues on the Manhattan Project, regretted his involvement with the development of the Atomic Bomb. He felt that the bomb was a product of a compartmentalized pure science divorced from any concerns of ethics and responsibility. Wilkins resolved that this division should be removed to make science “better related to man’s wider hopes and needs: dehumanizing aspects of science would be reduced, science would be a force for changing and improving society and social responsibility would be implicit in the nature of science itself”

These sentiments regarding the crisis in science were widespread and echoed by other speakers at the “Social Impact of Modern Biology” conference, including the French geneticist, Jacques Monod, and the biologist, Jacob Bronowski. The historian of science Jon Agar, in his 2008 article in the Journal of the British Society for the History of Science, on the change in science in the sixties views the crisis in science as a combination of three pervasive 'waves' in the scientific community: the first 'wave' produced scientific experts and public divergent opinions; the second ‘wave’ was the creation of organisations and movements (such as the British Society for Social Responsibility in Science) that could act as a forum to debate and question scientific practice, and the final wave reflected the pervasive attitude of 'inward inquiry' that questioned the concept of scientific knowledge and its value to society.

Wilkins considered the development of the Bomb and chemical and biological weapons were an abuse of science, but believed that it could be redeemed by shifting its purpose back to the needs of society.

“The man in the white coat knew best”

In the years following the 1970 conference, teaching on the new “Social Impact of the Biosciences” course at King’s College London gave Wilkins an opportunity to develop and share his views.  In a 1998 lecture, Wilkins reflected on the attitudes of the scientific community in 1970:

“…In 1970 many scientists saw science as giving certainty and truth; without science we would live largely in ignorance and superstition. Such scientists also had a simple faith that science applied would inevitably give us a better life. Roughly speaking, the scientist in the white coat knew best. That simple faith has considerably decreased. An important factor in this has been change in public attitudes to science; science has been criticised and open anti-science attitudes have increased. People are now less likely to believe ‘the man in a white coat knows best’ (in any case it is rather more likely than before that the scientist is a woman). It is important to realise that modern criticism of science has often arisen from the work of scientists e.g. on problems of pollution, climate change and environmental damage. Without that scientific work we would be barely aware that the problems existed. Also, solving these considerable problems depends considerably on continuing research. Similarly, medical studies have stimulated growth in broader, ‘mind-body  approach to patients rather than concentration on treatment with drugs. Although science has become increasingly part of people’s lives, the people have tended to become more critical of the effects of science in the modern world.“

Wilkins’ attitude to science was influenced by his research in the historical, philosophical and sociological ideas that the course explored. On the development of the concept of pure science, he wrote:

“During the Scientific Revolution of the 17th century pure and applied science were not regarded as separable. Francis Bacon (1561-1626) believed the value of science (and in fact its very truth) derived from the beneficial application of science. But in the early 19th century the snobbish demands of educating the upper classes in universities, especially in Germany, required that university science be freed from its links with ‘vulgar; industry (e.g. soap boiling) and made socially respectable as a pure academic discipline like classics or philosophy. Pure scientists became proud of the idea that their science might have no application at all. The idea of pure scientific knowledge became associated with the idea of absolute knowledge which could be separated from the way it was obtained and from the way it might be applied and was therefore value-free, (and based only on unbiased observation and logic).”

One important element to Maurice Wilkins’ attitude to social responsibility in science is his belief in the social conditioning of science, which suggests that as science is a human activity it would be conditioned by the social and cultural environment where it is carried out. This is important because “science dominates our whole culture, not just as a result of its direct applications, but because it influences general thinking and attitudes to life”. Therefore, being able to judge the nature and value of scientific knowledge has become ever more desirable. His own understanding bridged both the objective and relative understanding of knowledge:

“There are two processes, somewhat opposed, operating in science: there is the essential element of objectivity and rationality recognised by tradition, and without which science could not have built up an enormous set of coherent knowledge. On the other hand scientists’ thinking is always to an extent influenced by cultural forces and prejudice. The ‘logic’ of science can go far in ruling out inappropriate ways of thinking, thus enabling science to lead us to a partial view of the truth. The debate about social conditioning of science is about the relative importance of the objective rationality of science and the subjective conditioning of thought. This will vary with the situation.”

Wilkins’ key example of social conditioning of science was the work of the Soviet biologist Trofim Lysenko (1898-1976), whose own genetic theories were promoted in the USSR from 1928 to 1964 instead of the universally accepted Mendelian genetics. Lysenkoism was encouraged as it politically and philosophically was in keeping with Stalinist Russia. For Wilkins, it was the suppression of dissent and the central dogmatism that was the most corrosive aspect of the Lysenko affair. Yet the same charge he suggests (but not in such extreme fashion) can be made in those in the contemporary scientific world:

"while we condemn this we should recognise somewhat similar, thought not so extreme, dogmatism when some molecular biologist pronounces that human beings are ‘nothing but’ molecular machinery or when the psychologists take it for granted that IQ gives us a measure of intelligence on which we can base educational policy. Scientific knowledge need not be unavoidable truth. We should respect it but at the same time recognise its limitations, we should not jump to conclusions about its wider significance and we need to be very cautious in drawing parallels between animals and humans. “

 

To conclude…

“There can be no complete certainties in science but there can be a continuing process of enquiry and exploration"

Maurice Wilkins and social responsibility in science

In previous posts, I have concentrated on Wilkins' scientific career and in particular to his work on DNA and the double helix. However, in this post I would like to explore the "social responsibility" aspect of the project. This phrase has become associated with Maurice Wilkins due to his links to the British Society for Social Responsibility in Science (BSSRS) and the "Social Impact of the Biosciences" course at King's College London. Yet they also nicely summarise Wilkins' own attitude to the role of science in society and the need for a broader understanding of science and awareness of its implications. The following post will explore this general theme.
 Cambridge and the Second World War

While Maurice Wilkins was an undergraduate at St John's College, Cambridge, he became a member of the Cambridge Scientists' Anti-War Group. The group, led by the eminent x-ray crystallographer John Desmond Bernal, researched the protection of British civilians in the likely event of aerial bombardment in any forthcoming war. They examined the possibility of poison gas attacks and incendiary bomb damage. Wilkins investigated whether a single incendiary bomb could set fire to the top of a building, burn through, and destroy an entire building, burning through many floors (as seen in the photograph on the right). He ignited an incendiary bomb on a platform of conventional floorboards. Whilst the bomb easily ignited and caused much violent flashing and burning, it only caused only caused minimal damage since the fire burned up and not down. The results disappointed the group, who believed the experiments could have been a powerful propaganda tool exposing the evil of German air attacks in Republican Spain and the resultant devastation of the town of Guernica. Yet the results of the experiments played out in real life: as Wilkins saw the same effect during heavy bombing in Birmingham several years later:

"In the street where I live the roof of the doctor's house was burning, and the hoses drenching the outside of the roof did not seem effective. I went inside and saw the ceiling under the burning roof was intact, and I broke a hole in it to put a jet of water directly into the roof space. But when I had finished making the hole I could see through it that the fire had already been put out. I felt embarrassed that I had damaged the doctor's ceiling..." 

It was his move to study luminescence at Birmingham University in the Physics department under Mark Oliphant that would lead Wilkins to work on the development of radar and later the atomic bomb at Berkeley, California. His attitude to the bomb at the time was broadly supportive since its development was seen as crucial against continued Nazi aggression. Yet after the bomb's use in Hiroshima and Nagasaki he experienced growing unease about the consequences of such a weapon of mass destruction and realised that he wanted no further part in it. It was after the war whilst working at St Andrews University that, unbeknownst to him, he would catch the attention of MI5 due his subversive attitude towards the atom bomb. Wilkins was a keen supporter of sharing nuclear secrets for the improvement of international relations with the USSR. These views reported to MI5 and eventually led to his official monitoring (see previous post for details:  http://dnaandsocialresponsibility.blogspot.com/2010/08/maurice-wilkins-accused-of-spying-by.html ).

1960s and Political Activism

 

During the fifties and early sixties, he concentrated on his research on the structure of DNA but did not abandon his interest in the broader responsibilities of the scientist. During his Lasker Award speech in 1960, he emphasised that the importance of the double helix should be considered not only in terms of scientific knowledge but also in relation to the human benefit that may be created by applications of that knowledge. The winding down of the DNA work at King's and the award of the Nobel Prize gave him the freedom to return to the problems that captivated him as an undergraduate at Cambridge: science and its relation to society. In 1968, Wilkins became a prominent member of the public campaign to get the government biological research laboratory at Porton Down declassified and was one of the eight Nobel Prize winning scientists who wrote to the Prime Minster , Harold Wilson demanding that the work should be made public. It was through this network of scientists and other academics that Wilkins got involved in the group that became known as the British Society for Social Responsibility in Science (BSSRS) and was its President from 1969 to 1991. The society's importance and standing in the debate on science and values shown by the list of initial members as shown on the left.

Bogside Artists' mural of a boy running from CS gas in Derry

The aims of the Society were to stimulate an awareness of the social significance of science and the corresponding social responsibilities both individually and collectively, and to draw public attention to the implications and consequence of scientific development. BSSRS held its inaugural meeting in April 1969, attended by three hundred delegates and soon had a national body of a thousand members. The Society became a vocal advocate against the use of chemical and biological weapons in particular the use of CS gas. BSSRS led its own research into the gas' toxicity and organised its own team of doctors and social scientists to visit Londonderry, where the British Army had used the gas extensively. The Society gave evidence of the potential hazards to the government enquiry, the Himsworth Committee on the toxicity of CS Gas in 1969. BSSRS also launched pioneering projects on the effects of pollution such as the hazards associated with dumping toxic waste off the Cumberland Coast by the Atomic Energy Authority.

 

The largest event that BSSRS organised was an international conference on the "Social Impact of Modern Biology" held in London on November 1970. Over three days an average of seven hundred people per day gathered at the meeting that included talks from Maurice Wilkins, James Watson, Jacques Monod, Jacob Bronowski, David Bohm and Stephen and Hilary Rose. The conference acted as a forum to discuss the implications of scientific research with fellow scientists and the public and included such controversial subjects as "test tube babies" and questioning scientific objectivity. As the following letter from Maurice Wilkins to one of the participants, Professor Richard Doll makes clear the conference was largely a success. Many young scientists said that "it made them think" and it led to a successful book of the discussions of the conference, that has recently been republished ("The Social Impact of Modern Biology" edited by Watson Fuller). What typified the meeting was the discussion and the occasional clash (hence the mentioned abuse) between the "New Left" young radical scientists and the older more established scientists.

  

   

BSSRS never again achieved the same level of global coverage, but continued to have a presence especially through the work of local groups and its publication, Science for People.  The 1970 conference also led to the development of the "Social Impact of the Biosciences" course at King's College London that still runs to this day. Maurice Wilkins summed up its overall impact in his autobiography, "The Third Man of the Double Helix" (2003):  

[BSSRS] helped scientists to see there was no sharp distinction between pure and applied science, and that it paved the way for a broader, interdisciplinary approach to the problems of science and society".

 A few examples of the elaborate cover art and issues raised by Science for People

Correpondence between Maurice Wilkins and Sir Mark Oliphant

In this post, I want to highlight correspondence that I have recently come across between Maurice Wilkins and his fellow antipodean scientist, Sir Marcus Oliphant. The letters relate to Wilkins' biographical work on Sir John Randall for his Royal Society Memoir. Oliphant was a key figure for both Randall and Wilkins as he hired and supported them both as the Head of Physics at the University of Birmingham. It was there that the Randall-Wilkins partnership first began with research on on phosphorescence and continued in some degree with (the notable exception of the radar research by Randall and Wilkins' own involvement in the Manhattan Project ) until Sir John's retirement from King's College London in 1970. The correspondence between Oliphant and Wilkins are interesting in the insights that they shed regarding the creation of the cavity magnetron, shared ideas on scientific discovery and their mutual esteem for one another. 

Figure 1

Figure 1: Letter from Maurice Wilkins to Sir Mark Oliphant, dated 23 March 1987. Wilkins sends Oliphant a finished copy of his Royal Society Memoir on Sir John Randall. He relates that he decided in his own account of the creation of the cavity magnetron to deal with the rumours regarding the possibility of John Randall and Harry Boot being influenced by Russian scientists before the war. He also states a deep gratitude towards Oliphant for his support at Cambridge [where Oliphant was his personal tutor], Birmingham [where Oliphant hired Wilkins after he left Cambridge with a second class degree] and at Berkley [where Oliphant recruited him to be part of his team working on the Manhattan Project].  

Figure 2

Figure 3

Figure 4

 Figures 2-4: Letter from Sir Mark Oliphant to Maurice Wilkins, undated [1987]. The letter begins by passing on the sad news of the death of Rosa Oliphant, his wife of sixty three years but his pleasure on receiving Maurice's letter and Royal Society Memoir. Oliphant recounts his own memory of the discovery of the cavity magnetron and how he gave the problem to Randall and Boot; Randall's brilliance in using the Hertz wire-loop detector; the difficulties in the lab between James Sayers and Randall and how close the Russians had come with their own research. In regards to Wilkins' remarks about him, he thanks him and states that he is proud to be associated with a Nobel Prize winner in Medicine and contributing to what Ernest Rutherford called the 'stamp collecting' of quantitative science [which was anything other than pure physics]. 

The correspondence makes interesting reading because of the honesty and clarity with which the two scientists view the developments of the cavity magnetron and generally their lives as a whole. As Maurice Wilkins wrote in his autobiography: "[Oliphant] had a down-to-earth approach to physics, and believed physicists should make their own apparatus. This suited me well, since I had grown up in my family's workshop tradition...Altogether, Oliphant was very good to me. I felt we were on the same wavelength" (p32-33).

Figure 5

 The final letter in this series relates to my previous post regarding MI5 suspicion that Maurice Wilkins was a soviet spy (http://dnaandsocialresponsibility.blogspot.com/2010_08_01_archive.html). As a brief recap, MI5 began monitoring Wilkins after his defence of the British physicist and convicted spy, Alan Nunn May, was passed on by an informant when Wilkins was working in St Andrew University in 1946. Wilkins had argued heatedly in support of Niel Bohr's belief that atomic secrets should be shared with the international community. Oliphant states in the letter: " I remain convinced that Bohr's idea of openness, of a world without secrecy or barriers to any kind of communication, is the only way to achieve a world with out war".Sadly, we do not have Wilkins' reply but undoubtedly he would have shared the sentiment of his former mentor and friend.

A brief tour of the original artwork of Maurice Wilkins

In today's post, I wish to offer a short tour of original artwork done by Professor Maurice Wilkins in the form of a series of playful and inventive cartoons that rather helpfully illustrate elements of the philosophy of science. The origins of these cartoons stem from Maurice Wilkins' involvement in the teaching of the course, 'Social Impact of the Biosciences' here at King's. He would also illustrate his Eddington Memorial lectures on the 'Origins of the Modern World View' (1978) with quirky artwork to illustrate certain points such as the example below: where the ancient and the modern thinkers both accuse the other of hubris in their attempt to understand the world.

Or the artwork could be purely illustrative such as this example of a hierarchy of angels...

It is however, his 'Social Impact of the Biosciences' period that we see Wilkins the artist at his most creative peak. Not many artists have attempted to graphically depict in demonic form the social conditioning that impairs objective vision (see Figure 1) or the general schisms inherent in western culture through the guise of Jim Watson and Francis Crick building the double helix (see Figure 2).

Figure 1: Cartoon of Man having his objective vision tampered with by marauding demons representing social conditioning in the way people perceive society

Figure 2: Cartoon versions of Jim Watson and Francis Crick observe with resigned horror the inherent fractures in Western culture.