The crystal structure of perovskite.
Dr. Helen Megaw, born on June 1st 1907, died on February 26th at the age of 94. She was a well- known, highly respected and remarkable member of one of the most important scientific disciplines of the 20th century, namely the field of Crystallography. In her own words, this is �the branch of science concerned with the description of the structure and properties of condensed matter in terms of the spatial relationships of atoms and interatomic forces in an extended array�. I should explain that the term �extended array� means a �crystal� for it is the repeated stacking of molecular units in all directions that distinguishes a crystalline solid from non-crystalline substances like glass.
Helen was born into a distinguished Northern Irish family: her father was a famous judge and Ulster politician. In addition her uncle was a director of the Indian Medical Service, one brother built the Mersey tunnel, the Dartford tunnel, the Victoria line and Battersea power station, another brother was a Justice in the Court of Appeal, and one of her sisters researched diet and health in the 1930�s and marriage laws in Uganda in the 1950�s. Helen decided on a scientific career, starting first at Queen�s University, Belfast before moving to Girton College, at the University of Cambridge, to obtain her BA and PhD. From 1930 to 1934 she was a research student under the great, and some would say �infamous�, J.D. Bernal, along with Dorothy Crowfoot, later Hodgkin. Although she had already become interested in Crystallography while at school, having read Bragg�s X-rays and Crystal Structure, Bernal was a stimulating influence on her and happily confirmed her interest in crystals. Her choice of Crystallography was a wise one, because it was the one scientific discipline at the time that had already established itself as a place in which both men and women could engage on an equal basis, and she never, or rarely, was aware of any form of discrimination. She began her scientific career in the study of crystals by working on the structure of ice. The naming of an Antarctic island, Megaw Island, in her honour marked this work. If you want to find it, look at 66�55�S, 67�36�W.
In 1934 Helen spent a year in Vienna and then moved to work briefly under Professor Francis Simon at the Clarendon Laboratory, Oxford. This was followed by two years of school teaching before taking up a position at Philips Lamps Ltd in Mitcham in 1943. It was here that she worked out the crystal structure of a very important industrial material, barium titanate, which is used in capacitors, pressure sensitive devices and in a variety of other electrical and optical applications. This material, which crystallises in the so-called perovskite structure, belonged to the class of materials known as ferroelectrics, originally discovered around 1935. This structure is so famous and important that Helen�s name is permanently associated with it and with perovskite structures in general. In 1945, she moved back to Birkbeck College London, once again to work with Bernal, and in the following year, she was appointed to a post in the Cavendish Laboratory, Cambridge, where she remained for the rest of her scientific life.
At that time, the Cavendish Laboratory was under the leadership of the great William Lawrence Bragg, and as a result Helen found herself at a place where many important and well- known Crystallographers would pass through. She was there during the exciting double-helix days. However, she remained loyal to her chosen field of mineralogy and inorganic crystals. In 1951, Helen was responsible for providing a number of crystal structure diagrams to the Council of Industrial Design, which were then used in the designs for the textiles used at the Festival of Britain, including in the foyer of the Regatta Restaurant. In 1957, Helen wrote a book entitled simply �Ferroelectricity in Crystals�, the first of its kind, and for many years this became the bible for the fast growing international community of Ferroelectricians. A second book followed years later entitled �Crystal Structures: a Working Approach�, a fine text that illustrates well her unique approach to describing the architecture of crystals. In addition to ferroelectrics, by suggestion of W.H. Taylor (WHT), she took up an interest in the crystal structure of feldspars. These complicated materials make up most of the earth�s and moon�s surface, and are therefore of great significance in earth sciences. The first structure determination had been carried out by WHT before the war, but such is the complexity of this class of materials, there remained a great deal of unknown science to discover.
In 1989, Helen became the first woman to be awarded the prestigious Roebling Medal of the Mineralogical Society of America, and in 2000 at the age of 93 she was awarded an honorary degree at Queen�s University, Belfast.
Perhaps, now I can turn to my own involvement with Helen Megaw. I first met her in 1969 while at an international conference in Stony Brook, USA. She was looking for a postdoctoral assistant to work on crystal structure changes with temperature in a particular complicated perovskite material. Kathleen Lonsdale, who had been my Ph.D. supervisor in London, had recommended me to her. At the time I was working at the Chemistry Department in Harvard and my interest was in the crystallography of organic compounds. I therefore accepted Helen�s offer with some reluctance, because I felt that the subject of inorganic crystals was far too impenetrable for me.
However, I soon discovered that my boss was a remarkable person: formidable in some ways, but also very kind and patient. She had a particularly interesting gift: if you wanted to know what a particular crystal structure looked like from any particular direction, she could somehow turn it around in her mind and then sketch it for you. In the days before computer graphics, this was a very useful trick, especially for a crystallographer, who must somehow always be able to appreciate three-dimensional architecture.
I continued to work with Helen until her retirement in 1972. She retired to her home in Ballycastle to pursue her other interest, gardening. I recall how delighted she was to discover the plant called Perovskia, and this quickly made its way into her garden collection. Leaves of Perovskia featured on one of her Christmas cards. Helen�s death marks the passing of an era in science. In the words of Professor Robert E. Newnham of Pennsylvania State University: �Along with Kathleen Lonsdale and Dorothy Hodgkin, Helen Megaw is one of the grand old British school of women crystallographers who serve as role models for many of us � men and women alike�.
Professor Mike Glazer,
Clarendon Laboratory,Oxford
Click here for further details of the acheivements of Helen Megaw.
By permission, we reproduce here the appreciation first submitted to The Independent by David Blow and published on 7 February 2002.
A young Viennese chemist from a Jewish family, who arrived in Cambridge in 1936 to study under Desmond Bernal, Max Perutz became the leader of the movement which created molecular biology, and the head of the most successful research laboratory in Britain.
Throughout his life, his personal research focused on haemoglobin, a familiar protein molecule whose extraordinary range of properties illuminated every stage of the scientific development leading from spectroscopy and protein chemistry through three- dimensional structure to molecular genetics and medical application.
His achievements followed from a combination of several outstanding qualities, not all intellectual. His irresistible powers of gentle persuasion brought him long-term support from the Cavendish Professor of Physics at Cambridge, Sir Lawrence Bragg, and from the Secretary of the Medical Research Council, Sir Edward Mellanby, setting up a Medical Research Council Unit in 1947 for his work. He communicated ideas with extraordinary clarity and simplicity. Though he retained a strong Austrian accent, his written English was always elegant, compelling and stimulating. He seemed to write with a golden pen. He had a wonderful way of leading research, leaving his staff with the feeling they were free to decide their own way forward, while he created a vision of the long-term goals. And he had uncanny insight into the potential of young researchers seeking to work with him.
By the early 1950s he had drawn together an extraordinary group of people. His senior colleague was John Kendrew, like Max a chemist trained in crystallography, but in personality utterly different. Kendrew was a precise organiser, a gifted computer programmer, a man who knew exactly where he was going and how to get there. His research began by following Max's, but by brilliant organisation it later overtook him (by working on myoglobin, the much smaller brother of haemoglobin). There was also a PhD student with a degree in physics, whose dazzling intellect constantly darted from problem to problem. This man was Francis Crick. A postdoctoral researcher, a 22-year-old whizz kid named Jim Watson, turned up from Chicago.
Only 10 years later, Max Perutz and these three colleagues were all Nobel prizewinners. Max shared the Chemistry prize with Kendrew for their structural analyses of haemoglobin and myoglobin, and in the same year Crick and Watson (with Maurice Wilkins) won the prize for Medicine. But in the early 1950s all these men were unknown, achievements unrecognised, seeking how to use the techniques of physics and chemistry to understand the nature of biological matter.
There were other remarkable people in the group. Hugh Huxley studied with Max using the primitive electron microscopes then in existence. With brilliant insight, they decided Huxley should study muscle, an object ideally matched to the powers of the microscope. In his doctoral thesis in 1954, Hugh Huxley laid out the basic mechanism of muscle contraction. And Max's biochemical assistant, Vernon Ingram, was to discover the precise molecular nature of sickle- cell disease a couple of years later -- a change of one amino-acid in haemoglobin which we now recognise as the consequence of a single mutation.
The group first came to prominence with the achievement of the two young rebels -- Crick and Watson's analysis of DNA in 1953 revealed an exquisite structure whose fascinating implications caught the imagination immediately. Meanwhile Max's own research (and that of Kendrew) had got stuck. The methods of X-ray crystallography had been used to picture the molecular structure of many small molecules, up to the size of penicillin. Perutz and Kendrew wanted to use these methods on haemoglobin (and its partner in muscle, myoglobin). But the methods that worked for the smaller molecules seemed hopeless for these much larger structures.
While the DNA structure was being worked out, Max had a shattering insight for his own work. If he could attach a heavy atom to a specific site in the haemoglobin molecule, and if it didn't disrupt the structure of the molecule, and if he could make it crystallise in just the same way as ordinary haemoglobin, and if it made changes big enough to measure -- if all these things were true, he could see a way to use the methods of X-ray crystallography to image the haemoglobin molecule. He later wrote:
"As I developed my first X-ray photograph of mercury haemoglobin my mood
altered between sanguine hopes of immediate success and desperate
forebodings of all possible causes of failure. I was jubilant when the
diffraction spots appeared in exactly the same position as in the
mercury-free protein, but with slightly altered intensity, exactly as I had
hoped."
(Perutz, 1992)
The rest, as they say, is history. Crick and Watson's work led to the discovery of the genetic code, development of molecular genetics, methods to make bacteria produce large quantities of useful proteins such as specific antibodies, towards ways to clone stem cells. The work of Max Perutz led to an understanding of proteins themselves. These are the molecules which DNA specifies. They are also the molecules which control all chemical processes in a living cell and organise its structure. His methods have now been applied to tens of thousands of different proteins, giving clear insights into their mode of action.
In the late 1950s, after Bragg's retirement, Perutz's Unit was based in a small asbestos hut in the car park outside the Cavendish Laboratory in Cambridge. As the research group continued to grow, every empty room and disused shed on the site (including the building which was originally Lord Rutherford's stable) was converted to a laboratory for a different facet of molecular biology. Long before the Nobel Prizes, a report by Perutz convinced the Medical Research Council, then led by Sir Harold Himsworth, to build a large new laboratory for Perutz, Crick, Fred Sanger and others. The new building, known as the Laboratory of Molecular Biology, was completed in 1962 on the new site of Addenbrooke's Hospital, at the edge of Cambridge -- just in time before over-population of the Cavendish site led to any serious dispute.
The Laboratory of Molecular Biology has been an outstanding and continuous success, a breeding-ground for scientific achievement. In addition to the four Nobel Prizes awarded in 1962, which set the laboratory off to a splendid start, it has appeared in the Nobel lists again and again: for the creation of monoclonal antibodies by Cesar Milstein and Georges K�hler with immediate application to medicine, for Aaron Klug's deep analysis of the organisation of nucleic acids in chromatin and other types of nucleic acid structure, John Walker's long study of a beautiful protein (ATP synthase) which acts as a rotary dynamo which stores biochemical energy, and above all Fred Sanger's second Nobel Prize for inventing ways to find the sequence of bases in nucleic acids.
These are only the most visible of the laboratory's successes. Max has left
some clues to its achievements:
"I persuaded the Medical Research Council to appoint me Chairman of a
Governing Board, rather than as Director . . . This arrangement reserved
major decisions of scientific policy to the Board, and left their execution
to me . . . The Board met only rarely .. . This worked smoothly and left me
free to pursue my own research. Seeing the Chairman standing at the
laboratory bench or the X-ray tube, rather than sitting at his desk, set a
good example and raised morale. The Board never directed the laboratory's
research but tried to attract, or to keep, talented young people and gave
them a free hand."
(Perutz, 1995)
He always recognised the importance of new instrumental developments, and maintained large mechanical and electronic workshops, to which research workers had full access, directly passing their enthusiasm to the technical staff. The most characteristic feature was the tearoom, open to all, visited three times a day by most, an important centre for exchange of ideas and scientific news, which was managed for over 20 years by Max's wife, Gisela.
Meanwhile Max continued his own lifetime study of haemoglobin, "the molecular lung", and showed how concerted structural changes follow from its absorption of oxygen, causing it to be either fully oxygenated or fully reduced, and making it an ideal oxygen transporter. This demonstrated a general principle, since many enzymes and other proteins exploit a similar "allosteric" structural change to switch a process on or off. By collecting abnormal haemoglobins discovered throughout the world, he opened up "molecular pathology", relating a structural abnormality to disease. Long before mutant proteins could be created in the laboratory, he had a large collection of single-site mutants of haemoglobin.
The Medical Research Council had an inflexible rule that when a Director of one of its institutions reached the retirement age, he must not continue to work in the same laboratory. Adroitly, Max announced that he had never been the Director, only a Chairman, and after retirement he would continue to pursue his research as usual. This arrangement, warmly welcomed by the staff, allowed him to continue as he pleased. In retirement he wrote a lot, including book reviews on a wide range of topics from Karl Popper's view of Darwinism, and Fritz Haber's fanatical obsession with poison gases, to the social revolution caused by Carl Djerassi's synthesis of a contraceptive steroid, as well as several books of his own. He continued to travel, to collaborate with scientists from many nations. Above all, he pursued the endless ramifications of his deep understanding of haemoglobin and the many human diseases linked to it. He helped to design a useful drug to deliver oxygen to tumours and to damaged tissues.
In his scientific autobiography Science is Not a Quiet Life Max Perutz describes a number of scientific controversies surrounding his work, and how they were resolved. One of these involved a mutant haemoglobin, analysed incorrectly by its Japanese discoverers, suggesting a total conflict with his results. Max and his collaborators identified the mistake:
"I worried that if our Japanese colleagues learned of this disproof of their
findings, a poor student who blamed himself for their mistake might commit
suicide. To avoid such a tragedy, I invited them to publish a joint paper, a
gesture which earned me their lifelong friendship."
(Perutz, 1997)
Max Perutz was a deeply humane man, loved and admired by his colleagues, who combined that gift with exceptional powers of analysis, planning and leadership. His domed forehead suggested a mighty brain, but his small fingers were neat and dextrous. A robust and confident mountaineer, he studied glacier flow early in his career, so as to work in the Alps. A back injury in middle life ended his skiing, but he retained his love of mountains. While his achievements were crowned with many honours, they rode lightly on his shoulders. He refused any honour that would give him a title, and was known, and invariably addressed by colleagues, as "Max". He lived a quiet and unostentatious life, walking from his home to the laboratory almost daily until a few months before his death. His brain remained razor-sharp, he gave thrilling lectures, and his research continued. Within the last year he had made important contributions to the understanding of Huntington's disease, based on ideas of crystal nucleation.
He and his wife, Gisela, who survives him, were devoted to each other and to their two children, Robin and Vivien.
David Blow
References
Perutz, M.F. (1992)
Protein structure: new approaches to disease and therapy.
Freeman, New York.
Perutz, M.F. (1995)
The Medical Research Council Laboratory of Molecular Biology.
Molecular Medicine 2, 659-662.
Perytz, M.F. (1997)
Science is not a quiet life.
Unravelling the molecular mechanism ofhaemoglobin.
World Scientific, Singapore.
Brief summary of his life
Max Ferdinand Perutz, molecular biologist:
Richard Henderson wrote a brief reminiscence of Max Perutz on the day he died, published in the March 2002 issue of 'Crystallography News'. Click here for more details of his acheivments on this website.
Charles Taylor, who was a founder member of the British Crystallography Association, died in Salisbury Hospital on 6th March 2002. A devoted family man, he is survived by his wife Nancy, a daughter, and two sons as well as numerous grandchildren and great grandchildren.
Charles was best known in crystallographic circles for his pioneering work with Henry Lipson on the development of optical diffraction analogue (Optical Transform) methods, first suggested by Sir Lawrence Bragg in 1938. Long before the days of digital computers these methods promised to provide a much quicker alternative to the slow (even with Beevers-Lipson strips) standard procedure of calculating structure factors for trial crystal structures. This work with Lipson was carried out at the University of Manchester Institute of Science and Technology (UMIST) in the years 1948 -1965, first while completing a PhD but subsequently as a Lecturer and later still as a Reader. He obtained his D.Sc. in 1960 for his outstanding work there. During this period he continued to develop the theory and instrumentation for optical analogue methods, including optically prepared Fourier Syntheses, to the point where he was the acknowledged expert in the field. Amongst his achievements were many elegant ways of elucidating the structure of fibres using the optical analogue technique.
During the latter part of this period, however, electronic computers were beginning to make the optical methods redundant for single crystal structure determinations although they continued to be of use for disordered structures and poorly crystalline materials such as polymers. He began at this time, however, to develop other interests, notably in musical acoustics and the perception of sound � subjects for which an understanding of Fourier transforms was equally important � and gained a reputation as an inspirational teacher.
In 1965 he moved to South Wales to take up the Chair of Physics at University College Cardiff, together with the Directorship of the Viriamu Jones Laboratory. In this appointment he succeeded another famous crystallographer, A.J.C.Wilson, and the main research interest of the department was also X-ray crystallography. In 1980 he masterminded for the IUCr Commission on Teaching a series of pamphlets designed to �help students with no previous knowledge of X-ray diffraction to understand the general principles and to give some idea of what it can do�. He himself wrote the first of these entitled �A Non-Mathematical Introduction to X-ray Crystallography�. It was during his tenure in Cardiff that I joined Charles�s group as a young post- doc. The advent of lasers and the first computer-controlled film- writing devices gave a further boost to the Optical Transform methodology and with funding from Unesco we produced with George Harburn the book entitled �An Atlas of Optical Transforms�.
While in Cardiff his interest in acoustics and music (he was an accomplished pianist and organist) led him to establish a small research group concerned with the perception of sound. This lead to a collaboration with the Catgut Society of America (which pioneered a new, rational sequence of instruments for the violin family) and thence to the establishment of a system with which the vibrational modes of violins and guitars could be studied by holographic interferometry. He also established a degree course in �Physics and Music� that, during a period of rapid expansion of the Hi-Fi industry in Britain, was timely indeed.
While still at Cardiff Charles was appointed in 1977 as Visiting Professor of Experimental Physics at the Royal Institution and held this position until 1990. He was a great believer in the value of lecture demonstrations and built himself a considerable reputation for this genre, most notably on the topic of physics and music but also on others such as diffraction, image formation and colour. He became very concerned that science, and physics in particular, was perceived by children as a difficult, uninteresting subject and devoted much effort to arousing interest and encouraging a spirit of enquiry in children right down to those as young as 7 or 8. �Physics and music� was the subject for the first (of two) series of televised Christmas Lectures for Children that he was invited to give at the Royal Institution. Overall he gave some 150 lectures to schoolchildren at the RI as well as presenting 8 Friday Evening discourses there. In addition he undertook a number of lecture tours both in the UK and abroad. The Institute of Physics awarded him its Bragg medal for his contribution to Physics Education.
It was on one of his many lecture tours, when he visited Australia in the late 1980�s, that I last saw Charles. My most vivid, fond and lasting memory of him is with flowing grey hair crouched in concentration over a carpenter�s saw (bent into an �S�-shape) and convincingly extracting a melody from it using a violin bow. He was an inspiration to me and I am sure to many other young prospective scientists and he will be sadly missed.
Richard Welberry
The following obituary was published in 'The Times' of April 3rd 2002.
Scientist who inspired and entranced generations of students with his demonstrations of sound, colour and music
Charles Taylor was a first-rate scientist who could communicate effectively to a broad audience, and did so most notably in demonstration lectures. One of his best books, The Arts and Science of Lecture Demonstration (1988), explained how he did it. On the cover was James Gillray’s famous caricature showing a demonstration of some of the unfortunate physiological properties of laughing gas (discovered by Humphry Davy) in the lecture theatre of the Royal Institution shortly after its founding in 1799.
The Royal Institution has always been the home of the demonstration lecture and it became Taylor's natural home. He was appointed Royal Institution Professor of Experimental Physics in 1977, at the same time as Anthony Hewish and Peter Medawar became professors, and held his chair until 1988.
In the celebrated lecture theatre where Michael Faraday had performed, Taylor inspired and entranced generations of children with his lectures on the topics of sound, colour and - perhaps his favourite - "physics and music". Most memorable were his musical instruments made from wine glasses or blocks of plywood, with which he would illustrate the physics of sound. His young audiences always left buzzing with excitement.
His contributions to the Royal Institution's programmes was prodigious. He was an indefatigable and hugely popular schools' lecturer. In 1971 he gave his first series of televised Christmas lectures, and in 1989 he became only the third person since 1945 to have delivered a second series of Christmas lectures, with a demonstration called "Exploring Music".
The following year, he and the then director of the Royal Institution, Sir John Meurig Thomas, made the first Royal Institution Christmas lecture tour of Japan, lecturing to thousands of children in the Science Centre in Tokyo. This programme has since been followed by all subsequent Christmas lecturers.
Taylor's skills as a demonstration lecturer were also ideally suited to the format of the Institution's Friday Evening Discourses, the theatre of science founded by Faraday in 1826. The first of Taylor's nine discourses was given in 1969, and in 2000 he summed up his experience of "Presenting Science to Young Children" - a fitting swansong.
Charles Alfred Taylor was born in Hull and went to school there before going up to Queen Mary College, London, in 1940 to read physics. From there he was shortly evacuated to Cambridge. After graduation he joined the scientific war effort and worked on radio countermeasures for the Admiralty, first at the signals establishment at Haslemere, and later at the US Naval Research Laboratory in Washington and the Radio Research Laboratory at Harvard.
Back in England in 1946, he worked for a while for Metropolitan-Vicars Electrical in Manchester, doing high vacuum research. He then took a doctorate at Manchester University, studying the relationship between optical and X-ray diffraction. Appointed to the faculty, he was joint author in 1958 of the influential Fourier Transforms and X-ray Diffraction.
In 1965 he moved to Cardiff as Professor of Physics at University College, where he remained for the rest of his career. Although his research concentrated on X-ray diffraction (he jointly produced the Unesco Atlas of Optical Transformations in 1975, for instance), his work in acoustics (sometimes seen as the poor relation of physics) was highly influential, not only in his lecturing, but also in improving the acoustics of the Sherman Theatre in Cardiff. For the first half of the 1970s he was a vice-president of the Institute of Physics, which awarded him the Bragg Medal in 1983. Three years later he was the first recipient of the newly established Michael Faraday Award of the Royal Society, given for excellence in science communication.
Taylor married Nancy Truefitt in 1944 and they had two sons and a daughter. For the past 20 years or so they lived in Warminster, where he cared for his wife who developed acute rheumatoid arthritis. Though an unassuming man, he brought to the work of caring for her the blend of natural charm, profound insight and huge enthusiasm that also made him the perfect expositor of the wonder and excitement of scientific knowledge.
He is survived by his wife and children.
Charles Taylor, physicist, was born on August 14, 1922.
He died on March 7, 2002, aged 79.
Charles Taylor was also active in the International Union of Crystallography, he was Chairman of the Teaching Commission when he instigated their series of 'Teaching Pamphlets' for students. These were initially available as A5 sized paper booklets. They are now freely available on the IUCr Website.
He was a fascinating talker; at a BCA Annual meeting, in I think 1984, at Nottingham, he regaled Lesley Dent Glasser and I with tales of undergraduate life in Cambridge during the Second World War. The only undergraduates allowed to study at that time were those whose subjects, such as physics, were thought to be essential to the War effort. Prospective Arts students were expected to delay their studies and contribute to the War Effort in some more immediate way. However, there were still some Music tutors left in the University, who starved of their teaching of Music undergraduates, were happy to help science students with an amateur interest in music. This meant that Charles Taylor received excellent music tuition in Kings College Chapel from fine musicians; he described it as a fantastic experience he would probably not have had in more normal times.
Click here to return to BCA homepage