Robert Schlapp M.A.(Edin.), Ph.D.(Cantab.)

by Nicholas Kemmer

Robert Schlapp - or Robin as all his many friends called him - was born on 18th July 1899 and died on 31 May 1991. Like his older sister, Helene, and brother Walter, he was born in Edinburgh. His father Otto Schlapp, who had started his studies at the University of Jena, had settled in Edinburgh in 1887 shortly after his marriage to Anna Lotze, daughter of a prominent Lutheran Pastor and a talented musician. His move to Edinburgh came about as a result of an earlier visit in 1880-82 at the suggestion of Robert Fitzroy Bell. Once in Edinburgh Otto Schlapp completed his Promotionsschrift summa cum laude on Kant's 'Critique of Pure Reason'. Initially Otto Schlapp taught German at George Watson's Boys' College, but in due course his talents were more fully recognised by his appointment to a specially created lectureship in German which eventually led to the foundation of the Department of German of which he became the first professor.

Robin's background was therefore both academic and cultural, with special interest in music which was a lifelong passion. He went to school at George Watson's and emerged as Dux and Gold Medallist in 1917 having studied both the sciences and the classics. The war was a difficult time for the Schlapp family, teachers and colleagues gave them unstinted support, but in some respects they were 'enemy aliens' still. Otto Schlapp had renounced his German nationality in 1889 (though, in fact, he did not become a naturalised British citizen until just before the war). Robin, with a George Watson's Bursary, the Glass Mathematical Bursary, and first place in the Edinburgh University Bursary Competition, enlisted in 1917 under the 'Derby Scheme' but was posted to the 31st Battalion of the Middlesex Regiment, a labour battalion for those with any trace of 'enemy alien ancestry' "... doing navvying jobs, mostly on aerodromes ... with a representative cross-section of humanity ... down to some very dubious characters from London's East End.", an experience he later regarded as being "... most valuable in giving me an insight into the lights and shadows of human nature ...".

His subsequent M.A. Honours Course at the University of Edinburgh was taken jointly in the Departments of Mathematics and Natural Philosophy. The professor of the former was Edmund Whittaker (later Sir Edmund) who became a major influence in his life and subsequent career. Whittaker's department taught not only pure mathematics but also what later became Applied Mathematics. Robin's interest in this area was stimulated by some lectures of Dr Cargill G Knott - "Although not a particularly lucid lecturer, this experience turned my interests to Applied Mathematics ...". He recalled that the "good old man would open each term with a short prayer". In all Robin obtained ten class Medals and on graduating was awarded the Drummond Mathematical Scholarship.

He then went on to take his Ph.D. degree at Cambridge graduating in 1925. As Cambridge awarded its first Ph.D. in 1921, Robin Schlapp was one of the very early research students, when the concept of the Ph.D. was still novel in the ancient University and far from highly regarded. With typical modesty, he attributes his acceptance by Cambridge to Whittaker's influence although his Edinburgh record alone would have surely been enough. His supervisor was Sir Joseph Larmor, whose supervision, at best, seems to have been perfunctory, but again Robin, typically, attributes this to Larmor's "shyness", and goes on to express his surprise at passing his Ph.D. examination with work which, astonishingly, he described as "lacking any originality". Nevertheless his thesis on 'The Reflexion of X-rays from Crystals' was published soon after in the Philosophical Magazine, and led to his being awarded one of the first Commonwealth Fellowships to study at Yale. However, his Drummond Mathematical Fellowship still had some months to run, so he chose first to attend the Summer Semester lectures and seminars at the University of Göttingen. There he met Max Born, and one of his students Werner Heisenberg who a year later put forward a new theory called Quantum Mechanics. Schlapp may well have already known something about this work since he had spent his last year at St John's in Cambridge with Paul Dirac, who, through his supervisor, had seen a prepublication copy of Heisenberg's first paper. Dirac's subsequent work, giving a more complete formulation of Quantum Mechanics, is world famous, and many years later Schlapp was able to explain to his colleagues in Edinburgh how matrices, hitherto a notion familiar only to pure mathematicians, had suddenly become a part of Theoretical Physics. Surprisingly, in his account of the Cambridge days, Dirac is not mentioned, yet many years later, when I mentioned Robin's name to Dirac, his eyes lit up, remembering Robin as an old friend. The two men had only one later meeting, when Edinburgh University and Robin were jointly honoured in 1989 by a visit and lecture by the great man.

When Robin returned home he found an important change awaiting him. Following the retirement of Cargill G Knott, a new Chair, the Tait Chair of Natural Philosophy, had been founded to cover the field of Theoretical Physics and Applied Mathematics, and its first incumbent was to be Charles Galton Darwin. Darwin needed an assistant, and who better qualified than Robin. A major decision now had to be taken, to go to Yale or to accept the position in Edinburgh. Edinburgh won - "the pull of family ties and the old environment" was too great. Perhaps, this should not have deterred him from going first to Yale. The rest of his career was spent in Edinburgh except for two interludes. The first of these came very soon. Following a report he gave to the British Association on the Stark Effect (a topic close to Darwin's heart), he was invited to spend a year with J H van Vleck at the University of Wisconsin on a Rockefeller Fellowship. Here he worked with William Penney (later Lord Penney) on the paramagnetism of two types of ions. This work resulted in two major papers. Schlapp being the senior author of the second. When van Vleck received his share of the Nobel Prize in 1977 he said "In 1931 ... I had two postdoctoral students ... Penney and ... Schlapp. Their calculations on salts of the rare earth and iron groups ... when ... applied to the iron group ... are particularly striking and form the basis of modern magnetochemistry. Each time I read the paper (the second of the two papers) I am impressed how it contains all the essential ingredients of modem crystalline field theory".

His work at Wisconsin was sadly the summit of Robin Schlapp's scientific career. It provided his last paper on Theoretical Physics. Yet his contribution in the second half of his life has been equally memorable. The turning point in Robin's life was Darwin's retirement in 1936 to accept the position of Master of Christ's Church College, Cambridge, and the appointment of Max Born to succeed him in the Tait Chair. Born had been dismissed from his post by Hitler at the age of 50, and on his arrival in the UK was welcomed by Cambridge. However, the vacant Tait chair in Edinburgh seemed to offer a more fitting and permanent home for him and his family. Robin became his chief assistant, and no better person for that position could have been imagined, with his familiarity with German ways, along with his innate kindness, selflessness and patience. Unfortunately Born was unaware of how different the demands were on a professorial head of even a small Scottish University Department, adequate space for himself and his group being his main expectation. While Edinburgh and other sources generously provided funds to establish a 'Born School', the rest of Born's entourage consisted of just one well qualified young lecturer, Robin Schlapp, and a part time typist, Mrs Chester. All but some advanced lectures of Born's choice were left to his assistant. So was the administration of the department, to such an extent that the administrative correspondence from the University's offices was issued to a long list of professors and to Dr Robin Schlapp. Only midway through Born's 17-year term as head of department was a second lecturer, Andrew Nisbet, appointed.

It is not then surprising that during these years Robin's output in theoretical physics ceased. However his reputation grew as an excellent teacher and organiser, and during the war with an intake of young cadets requiring short courses in subjects involving mathematics, he both directed their studies and for some of the youngest of them acted in loco parentis. Many of his students from the immediate post-war period will remember his elegant demonstration of the principles of angular momentum and of the gyroscope, while sitting on a rotating stool holding an axle with rapidly rotating bicycle wheels on each end.

In 1931 Robin was called to take up an emergency appointment in Manchester whose Mathematics Department had just lost a senior exponent of Applied Mathematics. It was here that his brother worked and this may well have influenced his decision to take a year away, but most importantly it was while playing in his brother Walter's string quartet that he met his future wife Mary Fleure who played the second violin (Robin played the cello). A witness from that Mathematics Department recorded Robin coming into the department one day with the words "I just heard a blackbird singing the opening of the Mozart G Minor". But it was some years later, in 1940, after Mary had completed her medical studies that they were married in Edinburgh. Here she entered a medical career of teaching and research in Physiology, but she also engaged vigorously in the musical scene. Within four years two daughters were born and soon the second Schlapp family became a centre for music with Robin supporting on his large double bass. Sadly Mary lived only until 1975.

Much of Robin's work for the university was behind the scenes. From 1946 to 1950 he was the editor of the University Calendar "an arduous and thankless task" done without the help of a secretary or a telephone. Then for Born's retirement he felt that a Festschrift should be produced. Thirteen eminent people including Einstein contributed. Robin was alone responsible for the entire editing and for the production of a complete bibliography of Born's work, but there is no mention of this in the published volume.

I had the great honour of succeeding Max Born on his retirement in 1953. I had had rather little experience of working in British universities, and I must gladly and gratefully declare that the presence of Robin Schlapp and Andrew Nisbet by my side was indispensable for a smooth transition to a new man in the Chair.

There were soon important changes. The Department with its Tait Chair became "of Mathematical Physics". New accommodation across the road in Roxburgh Street became available and replaced the appallingly cramped space in the basement of the old Physics Department. Robin proposed that it be named the 'Tait Institute', and it was so christened and opened by Sir Edward Appleton the Principal. The indispensable Mrs Chester was promoted to full-time secretary. This allowed Robin to turn to some activities more worthy of him. The University called on him to represent it on may internal and outside bodies; he served several terms as President of the Edinburgh Mathematical Society. Then in 1958 he took on the local organisation of the International Congress of Mathematicians to be held in Edinburgh, the Central Committee meeting in Cambridge. This mammoth effort required two years of preparation for which he received the highest praise.

Robin Schlapp was an active fellow of the Royal Society of Edinburgh to which he was elected in 1927. He served on Council from 1959 to 1969 and as Curator of the Museum and Library from 1959 to 1969, and finally as Vice President until 1972. He was honoured by the Society with the award of the First Bicentennial Medal in 1983 which was bestowed on him by Her Majesty the Queen.

Robin was deeply interested and knowledgeable about the history of mathematics and made an important contribution to the Royal Society's edition of Isaac Newton's correspondence, a work initiated by Professor H W Turnbull and only completed after his death in 1978. Through this work he became an expert on Colin Campbell of Ardchattan (1644-1726) who corresponded with Isaac Newton. He was honoured by Glasgow as their Gibson Lecturer in the History of Mathematics in 1973 where he chose as his subject 'Inventors of the Calculus'.

Robin Schlapp was an expert translator from German. While organising the 1958 Mathematical Congress a request came through to me from a publisher's agent seeking a translator for a collection of essays by Wolfgang Pauli. Not realising the enormous extra workload arising from the congress I suggested Robin as the ideal person for the job, as he got on well with Pauli who could sometimes be difficult to satisfy. In the event the work was completed in an exemplary manner as attested by many eminent referees, but regrettably Pauli died just when the translation was complete. Unfortunately one of the referees had commented "I felt that Pauli's unique personality does not quite come through", and this was enough for his widow to exercise her right to veto publication, in spite of many efforts to persuade her otherwise. Only recently, when Robin's house was being cleared prior to his moving to live near his daughters, did a flimsy typist's copy turn up. There is now a very good chance that Robin's work will be published by Springer Verlag (Heidelberg) but sadly too late for Robin to be able to see it.

Robin had many other leisure interests including golf, sailing and gardening, coupled with a great love of Scotland, and of course chamber music. Perhaps this memoir can best be completed by quoting his own words:

"In concluding this account of a life spent mostly in Edinburgh - I now live only a few hundred yards from where I was born - I should say that it has been an immense privilege to have been able to serve the University for so long a period - as my father did before - doing work which I enjoyed, giving me opportunities for satisfying a wide range of interests and bringing me a multitude of congenial colleagues and good friends, some of great distinction".

Robert Schlapp was elected to the Royal Society of Edinburgh on 14 March 1927, his proposers being Sir Edmund Taylor Whittaker, Sir Charles Galton Darwin, David Gibb, Edward Thomas Copson. This obituary, written by Nicholas Kemmer, appears in the Royal Society of Edinburgh Year Book 1993, pages 111-114.