The International Tables

In 1924, a joint paper by William Astbury and Kathleen Yardley, entitled ‘Tabulated Data for the Examination of the 230 Space-Groups by Homogeneous X-Rays’, was published in the Philosophical Transactions of the Royal Society of London. These were the first tables of space groups produced in Britain, and their aim is summarised in the introductory paragraph:

‘The object of the present paper is to express the conclusions of mathematical crystallography in a form which shall be immediately useful to workers using homogeneous X-rays for the analysis of crystal structures. The results are directly applicable to such methods as the Bragg ionisation method, the powder method, the rotating crystal method, etc., and summarise in as compact a form as possible what inferences may be made from the experimental observations, whichever one of the 230 possible space-groups may happen to be under examination.’

It took a great deal of persuading on the part of Astbury to get his tables published, as Bragg deemed them completely unnecessary. He believed that all it required was a small amount of common sense for anybody to obtain the same results. Astbury pointed out that not all scientists were blessed with common sense, and fortunately won this particular fight.

In 1930, Ewald at Zurich called a meeting to consider the possibility of producing international tables for crystallography, combining the results achieved in different countries. Astbury was present, along with Hermann, Maugin, Niggli, Pauling, Schiebold and Wyckoff. As a result of the meeting, the International Tables were created, and still exist (in an updated form), acting as a main reference point for crystallographers, and serving the purpose of standardising notation (each space group is assigned a number in the tables). Again Astbury’s persuasive powers were required, when he was given the responsibility of convincing Niggli (editor of theZeitschrift fur Krystallographie) to remove his name from the working title of ‘Niggli International Tables’. Bernal attributes Astbury’s success in this task to his ‘transparent honesty and disinterestedness which were always evident at critical moments’.

In 1943, Ewald wrote to Astbury, asking for his assistance in looking at errors in the Table. Astbury replied that he had ‘hardly touched on space groups since those days’, his interests having long since moved on from pure crystallography.  [1]

by Imogen Clarke