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MAX VON LAUE 1879m1960 gq~qaav, 'Hp6KheITe, "rE6W p6pov... They told me, Herakleitos, they told me you were dead...

It is hard to believe that is no longer co-octogenarians and . To among us. He succumbed on 24 April to injuries suf- watch these venerable veterans of Science and long- fered in a car accident on 8 April. In him, we have time friends engaged in lively and often challenging lost a great leader in scientific thought, a champion conversation, seemingly unaffected by the passage of of intellectual integrity, a true friend, and an upright years, was a wonderful example and inspiration for man. In each of these respects he has had few peers old and young friends and associates. and the world is the poorer for his tragic death. What Laue has meant for X-ray On 9 October, last year, yon Laue's eightieth birth- need hardly be explained to the readers of this journal. day was celebrated in Berlin- in the Fritz His discovery of X-ray by crystals opened Haber Institute of the Gesellschaft, which up a most topical field of research at the very time Laue had, until recently, directed. This was a happy when the theory of atoms was in its earliest and harmonious day. Among the guests were the two infancy. Vigorously pursued in two directions, two A C 15 --35 514 MAX vo~ LAUE 1879-1960 new branches of grew out of his : Crystal- Acta Cryst. 2, 106, and gives the theory of the Borr- Structure Analysis in the hands of W. H. and W. L. mann effect ; it was succeeded by several recent papers Bragg, and X-ray through the work of on the closely related topic of energy flow in the case Moseley, M. de Broglie, M. Siegbahn and others. While of interference.--In two books Laue has collected it took many years until the super-stereochemistry and systematized his research in the fields of X-ray of crystal-structure analysis could be quantitatively and electron crystal . 'RSntgenstrahlinterferen- linked to the wave-mechanical theory of the chemical zen' first appeared in 1941 and in its third edition in bond, the results of X-ray spectroscopy on atomic 1960, after Laue's accident but still in time for him to energy levels provided an immediate and most valu- acknowledge it, and 'Materiewellen und ihre Inter- able check on the latest stages of the rapidly develop- ferenzen' in 1944. These books are likely to remain ing . the standard monographs in their fields. As in Laue's Laue himself took no part in the progress of crystal- first monograph, 'Das Relativitiitsprinzip' (Vol. 1 1911 structure analysis. He shared to some extent, though and later editions, Vol. 2 1921), a great wealth of not to the same degree, Lord Rutherford's feeling that Laue's own work is contained in these books, and working out the details of a structure was not a prob- problems often skipped over in other presentations lem of the fundamental type which appealed to him. are discussed and worked out in detail in a spirit of Once the diffraction experiments had clearly indicated painstaking honesty and responsibility of the author the periodic internal structure of crystal, as assumed towards his readers. in the structure theories, and the wave nature and Laue was, and considered himself, a , not wavelength of X-rays as discussed by Wien and a crystallographer or other specialist. The fields in Sommerfeld, this chapter of physics was satisfactorily, which his main achievements lie are if temporarily, closed for him. Indeed, soon after the and Theory of Radiation, Relativistic Electrodynamics publication of the two papers in the Bavarian Acad- and Optics, Theory of Space Charges in Electronic emy, Laue started on a purely optical diffraction Tubes, and . He was lecturer experiment of an entirely different type. (Privatdozent) in Berlin and (1908-12), Pro- This rather surprising indifference to the elaboration fessor in Ziirich (1912-14), Frankfurt (1914-19) and of his discovery for the advancement of -State Berlin (1919-43). From 1922 to 1943 he was acting Physics and of Theoretical Chemistry contrasts director of the Kaiser Wilhelm (later Max Planck) strongly with Laue's keen interest in X-ray Optics, Institute of Physics, and from 1951-58 Director of the which lasted throughout the whole span of 48 years Institute of the Max Planck Gesellschaft. after his first work. A few of the X-ray optical topics Laue received the for Physics in 1914, of Laue's papers may be mentioned: the generalization the in 1932 and the Helmholtz of the concept of the reciprocal lattice to non-orthog- Medal of the Deutsche Akademie on his birthday in onal crystals; the connection of line width and particle 1959. The hereditary nobility was bestowed on his size; the effect of particle shape in producing intensity father, a high officer in the quartermaster service of spikes in reciprocal space; the re-formulation of the the army, in 1913, and bears no direct relation to dynamical theory in terms of Fourier coefficients; the Laue's work. But on his seventieth and eightieth discussion of the possible influence of the Doppler birthdays, Laue received high civic distinctions. He frequency shift caused by the thermal of the was awarded honorary degrees and memberships of atoms; and a final series of important papers on Scientific Societies and Academies, among them the absorption in the case of simultaneous existence oI Royal Society (1949). more than one ray in the crystal. This last topic was The picture of Laue would be very incomplete worked out by Laue while he was interned, together without mention of his great merits in organizational with a group of German nuclear , near work for Science. He was, at various times, among the Cambridge in 1946; the manuscript was handed to editors of Zeitschrift fi~r Kristallographie, Zeitschrift fi~r the Editor of Acta at the Harvard meeting in 1948 Physi]c, Annalen der Physilc. ~hen, soon after the first at which the International Union of Crystallography world war, American money became available to a was constituted with Laue nominated its first and specially created commission of the Notgemeinschaft only Honorary President. The paper appeared in der Deutschen Wissenschaft, Laue was placed in charge MAX vow LAUE 1879-1960 515 of it. One of its major subsidies went to the preparation tual independence, Laue was neither to be threatened of the Strukturbericht. It would be a difficult but nor bribed into subservience. On many private oc- rewarding task to trace Laue's influence on the pro- casions and in two famous public addresses his voice gress of Physics in his wide-spread committee work. rang out like a clarion call for liberty of thought and When organization of science in Germany was not against oppression. Nobody who has not himself lived only in ruins at the end of the second world war, but in the atmosphere of distrust and fear of the Hitler also severely restricted by the occupation powers, the rdgime can appraise what clever and courageous deeds gradual emergence of regional Physical Societies and Laue's pronouncements at the opening of the Physics their eventual consolidation was largely due to Laue's Meeting in Wiirzburg in September 1933 and at the prudent and determined counsel. From 1946 to 1948 (officially forbidden) commemoration gathering for one of his main endeavours was the re-constitution of Fritz Haber (1934) were. Unknown but large is the the Physikalisch-Technische Reichsanstalt, formerly number of those scientists whose painful process of Charlottenburg, the prototype of National Physical emigration was quietly and efficiently eased by Laue's Laboratories, founded by Helmholtz, Siemens and advice and actual help. Laue was a great patriot and others. During the war, this institution had been he clearly recognized Germany's loss in the eviction scattered throughout Germany; that these parts could of so many of her best-trained scientists. But his be reassembled as the present Physikalisch-Technische human loyalty was even stronger than the patriotic Bundesanstalt in is in no small part appeal. As to himself, he found he had to stay where due to Laue's efforts. his duty lay, and that was to save from ruin what The probity of Laue's character suffered no inflexion could be saved. during the Hitler rdgime. While many respectable Max yon Laue's example, as a scientist and a man, scientists yielded to political pressure, first outwardly will continue to shine bright. 'aligning' themselves and in the end losing their spiri- P. P. EWALD.

t~hotograph of .Max yon Zaue: Courtesey, Lotte Meitner-Graf, A. R. P. S., .

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