The Analytic Theory of Point Systems, by J. D. Bernal


In 1923, Sir William Bragg received the following letter from the mineralogist, Arthur Hutchinson in Cambridge:
25th June 1923

Dear Sir William Bragg

I am venturing to write to you on behalf of a pupil of mine, Bernal by name, whose work on point systems has, I think, been sent to you - Bernal is I think quite a remark­able person; he is a shy, diffident, retiring kind of creat­ure, but something of a genius. He attended my course on Elementary Crystallography and I realized that he was inter­ested and was taking things in quickly. I did not however, realize (and he never let on) that he had got so keen that he spent the whole of his next vacation in developing a meth­od of dealing with point systems in the hope that it might be useful in X-ray work! When therefore, he suddenly appear­ed and deposited on my table a thick type-written MS., rather with the air of a dog bringing a poached rabbit to his master's feet, I was quite amazed - of course I make no pretence of being able to appraise its merit or even its use­fulness - still it seemed to me a remarkable effort for an undergraduate in his third year - and Professor H.F.Baker was much interested in it and I believe thinks well of it ...

This paper was thus written by John Desmond Bernal (1901-1971) when he was 21. It was submitted as a prize essay to Emmanuel College, Cambridge where Bernal was an undergraduate and earned him the Sudbury Hardyman prize of £30, but it also got him a post with Sir William Bragg and set him on a career in crystallography. The paper was then presented to the Cambridge Philosophical Society on 7th July 1923 as "The Analytic Theory of Crystals" but, although it was accepted, the paper was, on account of its length, never published. One manuscript copy, typed, we believe, by Mrs Eileen Bernal, has circulated in this department for many years, surviving precariously, but we now hasten to publish it in facsimile to avoid further danger of its loss.

Some of the circumstances of the production of this paper are described at length by Professor Dorothy Hodgkin, O.M., F.R.S., who was the earliest of Bernal's students and co-workers during his period in the crystallographic laborat­ory at Cambridge, in her biographical notice of Bernal (Biographical Memoirs of Fellows of the Royal Society, 26, 1980) which we quote for Prof. Hutchinson's letter and to which reference should be made for details of Bernal's scientific career.

The accompanying article, "X-rays and Crystal Structure" was written by Bernal in 1929 for the 14th Edition of the Encyclopaedia Britannica (and is here reproduced by kind permission of the copyright holders). It clearly follows from Bernal's essay. Bernal also wrote the corresponding article for the 1953 edition of the Encyclopaedia (Vol. 6, pp. 809-829). It ends with the sentences:

"The beating out of metal under the hammer, the brittleness of glass and the cleavage of mica, the plasticity of clay, the lightness of ice, the greasiness of oil, the elasticity of rubber, the contraction of muscle, the waving of hair and the hardening of a boiled egg are among the hundreds of phenomena that had already been completely or partially explained. They were an earnest of the millions of others, old or new, that still had to be explained."

In the period Bernal prepared a further version for the succeeding edition but, regrettably, this was not published because it was too long and had too many illustrations. Evidently the successes of crystallography in explaining the material world and Bernal's enthusiam had outrun commercial prudence!

J. D. Bernal was elected a Fellow of the Royal Society in 1938 for his work on the elucidation of the structures of biological molecules by the methods of X-ray crystallography and in the same year he succeeded P. M. S. Blackett as Professor of Physics here at Birkbeck College in the University of London. Almost immediately Bernal was drawn into the war but in 1946 the Birkbeck College Research Laboratory for bio-molecular structure was founded in two old houses at 21/22 Torrington Square (now the site of the library of the School of Oriental and African Studies). This was formally opened by Sir Lawrence Bragg on 1 July 1948 for which occasion Bernal wrote: "the central theme of the laboratory is the application of physical methods to the understanding of the structures and reactions of molecules in biological systems". The formal teaching of crystallography (M.Sc. by examination) began at Birkbeck also in 1948 and has continued ever since. In 1964 the Laboratory became the Department of Crystallo­graphy (moving into the new extension building and separating from the Department of physics) with Bernal as its first Head and first Professor of Crystallography, but in the same year Bernal suffered the first of a series of strokes. On his retirement in 1968 he was succeeded by C. H. Carlisle and in 1978 by T. L. Blundell, the present occupant of the established chair of crystallography and Head of the Department.

We have invited Professor Rolph Schwarzenberger of Warwick University to give an assessment of this, Bernal's first paper, which, by accident, has remained hitherto unpublished, and we are most grateful for his note which puts the paper into perspective and explains quaternions.

We believe that nothing could be more appropriate as Occasional Paper No. 1 from the Department of Crystallograhy which Bernal founded to continue the studies which he himself had advanced so much.

Alan Mackay
July 1981 

Based on the Emmanuel College, Cambridge, Prize Essay of 1923
Published as Occasional Paper No. 1 from the Department of Crystallography, Birkbeck College, University of London 1981
Published on the Web 2009 for the IUCr Commission on Mathematical and Theoretical Crystallography of the International Union of Crystallography with the kind permission of Birkbeck College