Australian Dictionary of Biography

Thomas Cherry, by Walter Freiberger, 1949

University of Melbourne Archives, UMA/I/1349

Sir Thomas MacFarland Cherry (1898-1966), professor of mathematics, was born on 21 May 1898 at Glen Iris, Melbourne, second son of Thomas Cherry, bacteriologist, and his English-born wife Edith Sarah, daughter of F. J. Gladman. Young Tom first attended a 'dame's school', walking four miles (6.4 km) each day, and became self-reliant and independent. Next came Scotch College, under the scholarly W. S. Littlejohn; Tom was dux and prefect in 1914. In the senior public examinations he won exhibitions in algebra, physics and chemistry.

At Ormond College, University of Melbourne (B.A. Hons, 1918), Cherry was influenced by the master D. K. Picken who emphasized algebra and by C. E. Weatherburn who advocated vector analysis. In the mathematics department were Professor E. J. Nanson and J. H. Michell. Cherry was awarded the Dixson scholarship for pure and mixed mathematics, the Professor Wilson prize for mathematics and natural philosophy, and the Wyselaskie scholarship in mathematics. Enlisting in the Australian Imperial Force on 25 July 1918, he was posted as a cadet to the Australian Flying Corps and 'learnt telegraphy and solo whist' before his discharge on 24 December.

When Cherry began to study medicine in 1919, his godfather Sir John MacFarland offered him a loan of £150 per annum to continue with mathematics at the University of Cambridge (B.A., 1922; Ph.D., 1924; Sc.D., 1950). At the end of his first year he was a Wrangler B* (starred for distinction). He was awarded an Isaac Newton scholarship, and named an undergraduate (1920-22) and a B.A. (1922-24) senior scholar at Trinity College. In 1924 he won the Smith prize for applied mathematics and was elected a fellow of Trinity College. He substituted for Professor E. A. Milne at Manchester in 1924-25 and for Professor C. G. (Sir Charles) Darwin in Edinburgh in 1927.

In 1923-28 Cherry undertook research on the ordinary differential equations of dynamics and celestial mechanics following J. H. Poincaré, with H. F. Baker and J. E. Littlewood as his local guides. He looked for integrals of these equations, periodic solutions, relations between different manifolds (families) of solutions, transitions between these families (bifurcations), and the possible complexities and pathologies of non-periodic solutions. There were eleven papers in this period and two a decade later, on this still most modern of topics. They reveal his method clearly: a general theory with pointed, illuminating examples, couched in a mixture of analysis and algebra, with applications from the classical dynamics and mathematical physics.

Cherry was a keen mountaineer and scout. After extensive experience on British mountains, he climbed the Matterhorn in Switzerland and traversed the French Pyrenees in winter. He worked easily and naturally, initially as scoutmaster and then as commissioner of the Boy Scouts in Cambridge, and founded a university rover crew in 1924. While organizing a competition for the chief scout, Lord Baden-Powell, at Cambridge, he met Olive Ellen Wright, a Girl Guide commissioner and leader of the wolf-cub pack from nearby Perse School. Having come home to Australia, he went back to Cambridge and married her on 24 January 1931 at Holy Trinity parish church. In Melbourne Cherry acted as scoutmaster of the Glen Iris troop and led various rover crews. He also founded the Melbourne University Mountaineering Club.

In March 1929 Cherry had returned to the University of Melbourne as professor of mathematics, pure and mixed, a post he held until 1952 when he reluctantly assumed the title of professor of applied mathematics. He had a heavy lecturing load of four, full courses, was chairman (1929-52) of the mathematics standing committee of the university's Schools Board, and was responsible for two major reforms of the mathematics syllabi of Victorian schools.

Cherry was notorious for lecturing in the style of the French mathematician P. S. de la Place and welcomed for also lecturing in the style of the German P. G. Lejeune Dirichlet. Terse like the former, he went from mountain top to mountain top, saying: 'It is easy to show that . . .', but he knew that it would take hours to make the climbs up and down the valleys between the peaks. Yet, like Dirichlet he was well organized and made everything follow in a natural progression, building on simple foundations from first principles; again like Dirichlet, he would bring into class a mere scrap of paper with the topic or a formula on it, look at it with an index finger raised to his face in dreamy contemplation, and then proceed to fill the hour with tension and excitement. In 1930 he introduced course-notes for students and replaced the first-year practice classes of one hundred or more students with tutorial groups of twelve.

During World War II Cherry worked on aspects of military research, among them the mathematics of the klystron and of J. G. Q. Worledge's arrays of radar aerials, the use of calculating machines, detonation—pressure and temperature in nitroglycerine films under impact—and operations research. His practical, physical insight, combined with his analytical mathematical skills, made him ideal for such work, as did his army and air force background.

Outside his work for the Department of Defence in the war years, Tom produced little or no research from 1929 to 1946. His energies were devoted to school and undergraduate matters. Undergraduate examination papers consumed a whole term; undergraduate needs were put above the interests of staff, especially the latter's research; courses showed detailed dovetailing; staff workloads, in the official teaching of four year-long courses and in the extra-curricular mathematical tasks expected by Cherry, were unreasonably high. For the schools, Cherry came to occupy a dominant role: he paid detailed attention to syllabus and to teaching method—based on investigation of the underlying problems—with his natural thoroughness and his 'research' attitude; he was concerned to preserve the independence of schools and their right to hold internal examinations up to and including the Leaving certificate; he constructed syllabi suitable for students who did not go on to university, as well as for the university entrance (matriculation) examination; he produced integrated mathematics courses for secondary schools—each subject was an organized and coherent mix of algebra, geometry, trigonometry and arithmetic, linking practice and theory, and grounded on his view of what was pedagogically sound.

Devotion to this great educational machine produced graduates who knew mathematics, and who were capable and confident of producing new mathematics themselves. But his methods had their limitations: the dovetailing of the courses left no easy entry points for new mathematical topics developed after 1920; students had the tools to extend what they had learned, but remained unfamiliar with the Continental and American theories which were changing the face of mathematics. Cherry kept himself informed through wide reading and individual contacts, but very little was spent on the stock of the university library after 1929.

In 1951 the Australian National Research Council awarded Cherry the Lyle medal; in 1954 he was elected a fellow of the Royal Society, London, and a foundation councillor of the Australian Academy of Science. He served the A.A.S. as secretary—in particular during the International Geophysical Year (1959) when he and a few others 'saved' Australian science's reputation—and as controversial president (1961-64), ending his term after leading a delegation to the Academia Sinica of Peking (Beijing) at a time when the Australian government did not recognize the communist government of China. He was also foundation president of the Australian Mathematical Society (1956-58) and of the Victorian Computer Society (1961-63).

The years from 1945 to 1965 saw ferment in the mathematical sciences in Melbourne. First, the university split the mathematics department by forming a department of statistics under Maurice Belz. Cherry's own research early in this period required vast amounts of numerical work and he read extensively on automatic computation. In 1956 the Commonwealth Scientific and Industrial Research Organization presented the university with the electronic computing machine which, after modification, became CSIRAC. Several appointments were made in computational mathematics. With his practical background, Cherry contributed to the reconstruction of the machine and to numerical methods. Once again, the university split the mathematics department, forming a department of computational mathematics (now computer science).

As a working colleague at all levels, Cherry had a single-mindedness that bordered on the ruthless. He was willing to pitch in himself, doing work of any kind, no matter how menial, but he did so as the one in control. He worked to be informed and prepared, and he was available to his staff every day at morning tea. His was a driving force: he had a very strong character, could correct behaviour with the lift of an eyebrow, and had a compelling public personality, with a kind and gentle manner. Until 1950 he was the power behind mathematics in Victoria. His research and reading drove his teaching. He was shaped in this regard by his practical, independent, Anglican family background and by his sense of responsibility in an isolated Australia. Accustomed to control, he did not find it easy to share power after 1945. While he was in some ways generous, he did not always have the background to appreciate the needs and aspirations of his colleagues for salary rises and promotions. His attitude to mathematics remained that of a practical man who was comfortable with methods based on first principles, and eventually, like others, he fell foul of David Hilbert's dictum: those who do not master and use the new, sharper and more powerful methods are destined to be left behind as mathematics progresses.

For thirty years from the time of his appointment Cherry took an active part as committee-member and president (1929-34, 1946-48) of the Mathematics Association of Victoria. He had the skill for distilling the essence of a complex situation, so much so that his frequent talks for the association made things deceptively simple, as well as elegant and precise. He was not afraid to talk about mathematics and even current research to teachers, and could do so at their levels. As a listener, he asked questions designed to bring speakers to the real point of their obscure or confused comments. The association began to lose the balance between mathematics and teaching when his influence was no longer felt.

Cherry retired from the mathematics department at the end of 1963, but continued to be involved in the A.A.S. and chaired the academic planning board of La Trobe University. In 1965 he was knighted. Soon after, he suffered a severe heart attack. He rapidly recovered and spent an academic year at the University of Washington, Seattle, United States of America, lecturing and writing his last published paper, on Hamiltonian differential equations. Survived by his wife and daughter, he died of myocardial infarction on 21 November 1966 at his Kew home and was buried in Gisborne cemetery.