It is our sad task to report that Amos deShalit died of acute pancreatitis on 2 Sept. at the age of 42. His untimely passing is a great loss to his family, to the world of physics, to his institute and country and to the entire world. A brilliant physicist, deShalit was one of the very few who are at home with both experiment and theory. He was a brilliant administrator; while he was head (1954-66), the nuclear physics department at the Weizmann Institute, Rehovoth (Israel) developed into a leading center for the study of nuclear and particle physics, rivaled in its impact by only a handful of other institutions. He was a brilliant educator; since 1963 he had been actively involved in improving science education in Israel, particularly in the secondary schools. This activity was recently made formal by the creation at Weizmann of a department of science teaching that was headed by deShalit. Deeply committed to his country, he was much concerned with the problems of the Arab population.

RECENTLY THE VALUE of pure research to the US nation has come into question. Although the federal government has steadily increased its support of pure research since the Second World War, attempts to determine the value of pure-research activities to the national economy have been inconclusive. Project Hindsight concluded that very little basic research carried on in university laboratories had contributed to the development of weapons systems since the war and implied that consequently there was little point in the Defense Department's continued support of pure research in universities. On the other hand, those individuals who support increased funding of pure research by the federal government point out that the nation's most rapidly growing industries are those that have invested most heavily in research, with the implied conclusion that an investment in pure research will result in an expanded national economy.

NUCLEAR PHYSICS emerged from the war years in the 1940's as a field rich in applications but pitifully weak in fundamental understanding. In the next two decades, building on the impetus and insight achieved in the crash program of the 1940's, major progress has been made both in understanding and in application. The rich canvas of nuclear phenomena has been sketched in, and exquisite detail has emerged in many areas. Many other areas remain blank and await exploration and exploitation; indeed it has been necessary, repeatedly, to extend the boundaries of the canvas itself. Nuclear physics remains in the frontiers of man's understanding of his universe. To a unique degree it has also forced significant changes in contemporary society and civilization.

A long and careful search for double beta decay (simultaneous emission of two electrons) appears to confirm that leptons are conserved. C. S. Wu, R. K. Bardin, P. J. Gollon and J. D. Ullman of Columbia have found 69 events that may be the kind expected if leptons are conserved—that is, events in which two electrons are emitted with two neutrinos. Meanwhile, in 1100 hours of observation, they found only one event that might be a double beta decay without neutrinos.

Besides its high-energy-physics research (PHYSICS TODAY, February, page 57) Argonne National Laboratory has strong programs in nuclear, atomic and solid-state physics, and it is building a high-flux research reactor. During a recent visit there we spoke to some of the people in charge of these programs.

George Gamow, professor of theoretical physics at the University of Colorado, died 20 Aug. after a long illness. A resident of the US since 1934 and a citizen since 1940, he was born in Odessa, Russia on 4 March 1904. He was educated in the Normal School in Odessa and at the University of Leningrad, where he received his PhD in 1928.

With the death of Otto Hahn on 28 July the world has lost one of the most significant and successful scientists of our century. His most famous discovery, the fission of the uranium nucleus, has basically changed the political and economic world picture. Perhaps this discovery and its results have been more debated than any previous scientific step forward. There has hardly ever been a scientist who has been so generally respected and loved. It would be unjust, however, when considering Otto Hahn's scientific achievements, to think only of this one great discovery, made at the age of nearly 60, although it was the conclusion and crowning of his scientific career.

On 22 May a group of the nation's most distinguished scientists—including four Nobel laureates—gathered at Columbia University to take part in a one-day symposium marking the retirement of Isidor I. Rabi. Rabi, himself a Nobel laureate, completed a career that spans nearly 40 years with Columbia.

Paul A. Flinn, a Carnegie-Mellon University professor, has received one of the two Argonne Universities Association Distinguished Appointment Awards for 1971. The award will enable Flinn, who is professor of physics and metallurgy and materials science, principal research metallurgical engineer and senior fellow at Mellon Institute of Science, to devote next year exclusively to the study of glasses and amorphous materials at Argonne National Laboratory. He will also receive a $5000 merit award.

The isomer shift in Mossbauer spectroscopy refers to changes in the resonance energy resulting from electric-monopole hyperfine interaction between the finite nuclear-charge distribution and the electron density at the nucleus. For a typical source-absorber experiment, the shifts depend on two factors: the difference in mean radii for the resonant nuclear levels and the difference in electron densities at source and absorber nuclei. Thus, any treatment of isomer shifts implicitly involves nuclear-structure considerations together with determinations of electron-charge distributions in condensed matter. For a given Mossbauer isotope, the nuclear factor is essentially constant and a determination of this quantity (by calculation or electrondensity calibration) allows observed isomer shifts to be interpreted, in principle, as relative electron densities at source and absorber. The isomer or chemical shift was first reported in 1960 by O. C. Kistner and A. W. Sunyar for the case of an «FeiOa absorber and source of Co 57 in stainless steel. This important feature of Mossbauer spectroscopy has motivated a significant amount of research during the ensuing years, and this work is authoritatively surveyed in the present volume.