Robert Rankin

Quietly dignified and with an unmistakable air of authority, he was an outstanding scholar whose interests ranged widely. His manner was reserved but he was unfailingly considerate and kindly.

A native of Wigtownshire and a son of the manse, Robert was educated at Fettes College, Edinburgh, and Clare College, Cambridge. In those early years he had to make frequent train journeys on the line between Newton Stewart and Dumfries, one of the most scenic in Scotland and, sadly, long abandoned. His lifelong love of the Scottish countryside may well have dated from then.

At Cambridge he took the Mathematical Tripos, becoming a Wrangler in 1936 and completing Part III the following year. Two major figures dominated the pure mathematical scene at that time - J E Littlewood and G H Hardy. Under their influence, Robert began research in number theory, supervised first by A E Ingham and subsequently by Hardy himself. His earliest research paper, on the distance between consecutive prime numbers, was published in 1938. Other papers followed in 1939, and in that year he was made a Fellow of Clare College, a position he held until 1951.

His promising career in pure mathematics was put on hold by the Second World War. Joining the Ministry of Supply in 1940, he was sent first to Fort Halstead and then to a centre in Wales, to work on rockets. The value of his broad mathematical training was soon evident: he turned his formidable mind to developing a theory that would predict the motion of a rocket during the burning phase, given certain initial data. Although his research was backed up by some experimental work, the latter was not given priority by the government and paled in comparison with what the Germans were doing in Peenemunde, which eventually led to the deployment of the V2.

When, after the war, his work was de-classified, Robert prepared a huge paper entitled The mathematical theory of the motion of rotated and unrotated rockets, a technical tour de force which was published by the Royal Society of London in 1949. The Russians, no laggards in this field, were quick to recognise its merits and published a translation two years later.

Returning to Cambridge in 1945, Robert became a faculty assistant lecturer and, later, a university lecturer in mathematics. Perhaps as relief from his war work, he went back to pure mathematics, picking up the threads of his earlier research. He also held two college posts and served for four years as mathematical secretary and editor of the Proceedings of the Cambridge Philosophical Society.

Two unusual papers from this time deserve special mention. One was inspired by Dorothy L Sayers's novel The Nine Tailors, which featured campanology. In his paper, Robert used the theory of permutation groups (a branch of algebra) to show certain peals of bells were impossible, subject to the conventional restrictions of change-ringing. Some mathematicians in Glasgow will recall his giving a talk on this, years later, with illustrations on the clavichord. The reaction of the bell-ringing fraternity to his work is not recorded.

The second paper, remarkably, was written entirely in Gaelic and has an eye-catching title which was translated as The numbering of Fionn's and Dubhan's men and the story of Josephus and the 40 Jews. This found a home in the Proceedings of the Royal Irish Academy, the author's name appearing as Rob Alasdair Mac Fhraing. In due course, the paper was reviewed by one of the few mathematicians capable of reading it - R A Rankin!

After a three-year spell as Mason professor of pure mathematics at Birmingham University, Robert was appointed to the chair of mathematics at Glasgow University in 1954, succeeding Professor T M MacRobert. With his wife and family, he moved into the large house at 10, The Square, traditionally associated with this post, and lived there until he retired.

At the time of his appointment, the university was still hierarchical in its organisation. Robert automatically became head of the mathematics department and ran it with exemplary efficiency for the next 26 years. He expected his staff to share his commitment to excellence; and, in return, he was rewarded by loyalty. It was a privilege to have been part of this team. During his long tenure, many changes were introduced. In particular, class syllabuses were revised and modernised, staff numbers were increased, and research activites encouraged.

As a senior academic, whose judgment and meticulous grasp of detail were greatly valued, he became involved in much committee work. He held the post of dean of the faculty of science in the late sixties and was clerk of senate from 1971 to 1978.

An accomplished musician, he represented the university for many years on the board of the Royal Scottish Academy of Music and Drama. For his service to the academy, particularly when close links were being forged with Gilmorehill, he was made an FRSAMD.

Robert played an active part in many other outside bodies. Elected a fellow of the Royal Society of Edinburgh in 1955, he was a vice-president for three years from 1960. He also served as president of the Edinburgh Mathematical Society, as a founder member and chairman of the Scottish Mathematical Council, as honorary president of the Glasgow Gaelic Society, and as vice-president of the Scottish Gaelic Texts Society.

Deeply interested in environmental issues, he chaired the Clyde Estuary Amenity Council (1969-1982) at a time when there was much concern about developments at such places as Hunterston, Ardyne Point, and Portavadie.

Despite so many demands on his time and energy, he continued to produce a steady stream of papers on a range of topics in pure mathematics. In addition, he wrote a large textbook on mathematical analysis, for the use of undergraduates, and two monographs, one on the modular group and the other on modular forms and functions. The quality of his research was recognised by the award of the Keith Prize of the Royal Society of Edinburgh for 1961-63, and by two awards from the London Mathematical Society, the Senior Whitehead Prize in 1987 and the De Morgan Medal - its highest honour - in 1998.

His intellectual activities did not preclude excursions into things practical. In his leisure time he assembled a harpsichord from a kit; and he built a boat in the basement of his house, parrying the occasional facetious comment that he might have forgotten to ensure it could be extricated when completed. Hillwalking was always a passion - and tales of how, striding ahead, he left younger colleagues puffing in his wake, became the stuff of departmental legend.

In his retirement he continued to visit the university regularly as a honorary senior research fellow. Latterly, he spent much time on the history of mathematics. In particular, jointly with the American B C Berndt, he edited letters by the famous Indian mathematician S A Ramanujan and published them, with accompanying commentary, in 1995.

The bulwark of his busy life was his family. He and his wife, Mary, were devoted to each other and to their four children. The happy atmosphere of the Rankin home was always apparent to the many colleagues, students, and visitors who enjoyed its warm hospitality.

Mary's death in 1996 was a devastating blow to Robert and, in the years that followed, he suffered increasingly from ill health. As recently as last December, he insisted - against advice - on making a trip to London to give a talk about one of his predecessors in the Glasgow chair, Hugh Blackburn, husband of artist Jemima Blackburn and friend of Lord Kelvin. It was typical of Robert that he

wanted to live a full life to the end.