The Crystallographic Community

The Telegraph 5 October 2007

Professor Durward Cruickshank

Durward Cruickshank , who has died aged 83, was an eminent mathematical crystallographer and Professor of Chemistry at the University of Manchester Institute of Science and Technology (UMIST) from 1967 to 1984. 

His careful work on the analysis of the thermal motion of atoms in crystal structures is known to every student of crystallography, and his development of much of the theoretical basis for the refinement of molecular structures in the 1950s and 1960s was crucial to the advancement of the subject. Cruickshank was in his twenties when he wrote some of his most influential papers, but his interest in crystallographic mathematical detail never waned, and more recently he had been addressing the problems of accuracy and precision in protein crystal structures. The Cruickshank Diffraction Precision Index (DPI) is now being added to the three-dimensional data from protein structures deposited in the Protein Data Bank (PDB). 

Durward William John Cruickshank was born on March 7 1924 and educated at St Lawrence College, Ramsgate, and Loughborough College, where he took a First in Engineering. In 1944 he also gained an external London University degree before studying Mathematics at Cambridge, where he was awarded another doctorate in 1961. For a short time he worked in naval operational research at the Admiralty. 

Cruickshank later maintained that he owed his career as a crystallographer to Sir Gordon Cox, who had invited him to Leeds where, as Professor of Chemistry, he had established a thriving chemical crystallography unit. In 1946 Cruickshank joined Cox's group as a temporary research assistant. 

Four years later Cruickshank was appointed a lecturer in Mathematical Chemistry at Leeds, and it was during this period that the first computers became available for crystallographic calculations. Cox was quick to exploit this "invention" and Cruickshank made frequent journeys to Manchester for all-night sessions on the Ferranti Mark I machine as early as 1952. 

Crystallographers were well placed to make use of computers, since they had already developed ways of breaking down the calculations into parts, using Fourier Transforms and devices such as Beevers-Lipson strips. By 1957 Leeds University had its own ICL Pegasus computer, with the crystallographers among its main users. 

Cruickshank also attended the first Cambridge summer school on Programme Design and Automatic Digital Computing Machines, learning much about the techniques he would use subsequently in his research. 

Not only did it introduce him to the principles of programming, machine codes and binary arithmetic, but he also met BV Bowden, who went on to work for Ferranti and who in 1967 (as Lord Bowden and the principal of UMIST) invited Cruickshank to move from Glasgow, where he had held the Joseph Black Chair of Chemistry from 1962, to Manchester. 

Cruickshank remained at UMIST for the rest of his academic career — as Professor of Theoretical Chemistry (1967-84), deputy principal (1971-72) and – from his retirement in 1983 – as emeritus professor. Cruickshank was awarded the Royal Society of Chemistry Medal for Structural Chemistry in 1978, and elected a Fellow of the Royal Society the following year. 

In retirement he worked (notably with Helliwell and Moffat) on the complicated mathematical treatment of Laue diffraction data and published several journal articles on the subject.

Apart from continuing his scientific studies, in his retirement Cruickshank began to research the genealogy of his family, visiting the immense records archive in Salt Lake City.

He also made several trips to the Antarctic and Arctic; on one, in 1998, he followed a journey made by a whaling ancestor some 200 years earlier. 

Cruickshank was treasurer (1966-70) of the International Union of Crystallography, and its general secretary and treasurer from 1970 to 1972. He was the first Dorothy Hodgkin lecturer (1991) and the Bragg lecturer in 1997. 

Durward Cruickshank 's wife Marjorie died in 1983, and he is survived by their son and daughter.