The Rutherford Memorial Lecture, 1960 - The development of X-ray analysis

Abstract

It is now nearly fifty years ago that von Laue made his discovery of X-ray diffraction by crystals. I propose in this Rutherford Lecture to survey the stages by which the science of X-ray analysis has developed since that time. It is interesting to trace the converging lines of thought and experience which initiate a new science and determine its rate of development. In the first place the time must be ripe; there must have been a series of recent advances in knowledge which potentially enable the new advance to be made. At the same time, it is often by chance that the advances, made in several branches of science, are brought together and that their joint significance is realized. The situation may be compared to that of a supersaturated solution, which requires a nucleus on which crystallization can begin. It was a favourite saying of my father’s that, after a year’s research, one realizes it could have been done in a week. This saying must of course not be interpreted literally; there are many cases when data must be laboriously collected before one can arrive at an answer. He was, I think, referring to the fumblings of thought, the exploration of alleys which turned out to be blind, the lack of knowledge of some vital piece of information which was there for the asking if only one had known where to ask. All of us must have said to ourselves at one time or another in our research, ‘How blind I have been’. X-ray analysis is particularly a subject where a review of these factors is interesting, because it has developed within living memory and it is so well integrated. It is a branch of research with a discipline of its own, and one with features rather unlike those of any other science. It depends on no abstruse principles and does not require apparatus of any great elaboration. Success in pursuing it demands that particular turn of mind which would lead to the successful cracking of a difficult cipher. Those who pursue it are a closely united band who talk the same language and keep closely in touch with each other. At the same time it is a typical borderline science, which has had a great influence on many other sciences and has used their bodies of knowledge as a basis for its discoveries. Having worked in the field of X-ray analysis during my whole scientific career, I have hoped that the Rutherford Lecture would be a suitable occasion for placing on record my recollection of its early stages and my judgement as to what were the crucial developments which enabled it to pass from one stage to the next.