April 10, 1965 NATURE ATOM

No. 49so April 10, 1965 NATURE 123

Since, quite apart from financial considerations, there world picture. Written from the British perspective _all;d must be some relation between the output of different largely from documents only in GDvernment files, Bnta~n categories of trained manpower and national needs and and Atomic Energy 1939-1945 brings to light many _n~w opportunities, it would seem wise to proceed circumspectly and, in some ways, extraordinary facts about British with university expansion pending the enquiry into the activities in the early 1940's. For one who has investigated this early history from reasons for the shortage of candidates in science and documents available in the United States, the most technology and the institution of appropriate measures to important revelation in Mrs. GDwing's book is the extent deal with the situation which themselves may well require of British accomplishment before the summer of 1941. time to take effect. There are some suggestive passages in I knew that the optimistic conclusions of the Maud this connexion in the recent presidential report of Dr. Report in the summer of 1941 had sparked the first real Caryl Haskins to the Carnegie Institution of Washington effort to investigate the possibilities of an atomic weapon (see Nature, 206, I, 1965), and while some attention to in the United States; but I had never imagined that the the content of university courses, to transfer between physical principles on which that Report was based were courses, and perhaps to more flexibility in the subjects understood by some scientists in Britain as early as February 1940. required for entry may be desirable, any relaxation of Mrs. GDwing describes the early and well-founded university standards would be most unwise. If it did not scepticism which dominated British t~inking in 193~. result at once in higher wastage, it could adversely affect Especially after the outbreak of war m September, It university teaching and offset any potential improvements seemed unlikely that atomic energy could play any part in the actual teaching-if it did not also lead ultimately in the impending conflict. Some scientists, like ~tto to lower standards of professional competence. A note Frisch, questioned whether a bomb would be poss_Ible on failure rates and university standards in Australia by even if some isotope separation process could be devised 235 Prof. J. M. Blatt in Vestes for December 1964 fully sub to accomplish a ten-fold enr~chmen~ of the .U con~ent stantiates this view. in natural uranium. Then, m argmng the pomt, Fnsch began to have some doubts about its. validitY:. . _With It seems probable from this report that the real problem Rudolph Peierls he explored the theoretical possibility of lies in the schools themselves. It is useless to blame the a weapon using pure uranium-235. This proved the key school-leaver, who largely takes his or her ideas as to a to the problem. In a short paper, Peierls and Frisch career from a careers master or mistress, from a particular summarized their theoretical calculations, which showed teacher, from parents or from the general image of a that a weapon could be made with as little as 1 kg of profession or career in the public mind. It is here that uranium-235, and suggested the rapid assembly ?f sub critical masses of uranium as the method for firmg the immediate correction could be applied, and this calls bomb. The document, reproduced in the appendix, is especially for the co-operation of professional institutions unfortunately undated, but it must have been written as well as of the schools and education authorities. There early in 1940. . . . . is no reason to believe-all the evidence is to the contrary Did the British delay conveymg this mformat10n to -that the youth of to-day is reluctant to enter scientific American scientists for almost eighteen months ? (No copy of the memorandum has been found in United States or technological careers to the extent that is needed if files.) How could such an oversight have. occurred, the opportunities and rewards of those careers are accur especially in view of British concern at the tune about ately and imaginatively presented-this is not to deny, the lack of urgency and direction in the American pro however, that there are some where the prospects, the gramme ? Part of the answer may lie in _the lac~ of status or the financial rewards require some improvement. administrative machinery for the exchange of mformatiOn, part in the understandable reluctance to commit oneself on the basis of theory alone. But there are also traces of national pride and a lack of confidence in foreign security BRITISH PERSPECTIVE ON THE systems within the structure of an otherwise remark- ably co-operative Anglo-American. alliance. . ATOM Such motives operated on both sides of the Atlantic, as Britain and Atomic Energy 1939-1945 both the American and the British volumes make clear. By Margaret GDwing. With an introductory chapter by Some Americans were pleased to find convenient reasnos Kenneth Jay. Pp. xvi+464+ 14 plates. (London: for terminating interchange in 1943; but, as Mrs. GDwing Macmillan and Co., Ltd.; New York: St. Martin's Press, points out, the British brought some of this on them Inc., 1964.) 55s. net. selves. Grossly underestimating the electric effect o~ ~he Maud Report on the American programme, the Bntish EW accomplishments in science have had more hesitated in accepting American proposals for a fully F immediate and profound impact than the discovery joint effort. By the time the British had decided to act of nuclear fission by Hahn and Strassmann in late 1938. in July 1942, American confidence had increased to the As the startling news from Germany swept across the point that full co-operation with the British no longer world, scientists in many countries rushed to their seemed necessary. . laboratories to verify the incredible report. Within seven Thus Mrs. Gowing sets the stage for a careful descnp years technology transformed the Hahn-Strassmann tion of the ups and down of the alliance during the War: experiment into a matter of consequence for all nations, the collapse of collaboration in late 1942, Churchill's but only recently have we begtm to assemble an adequate appeals to Roosevelt for a resumption of interchange, history of that transformation. consideration of an independent British programme, the To be sure, the American effort was widely publicized negotiation of the Quebec Agreement ill; the summer of by the Smyth Report, which appeared shortly after 1943 the British missions to tho Umted States and the dramatic introduction of atomic energy into world Cana:da, the controversy over tho French scientists, and affairs in August 1945. Further details were released in the Hyde Park aide-memoire of 1944. . . 1962 in The New World, the first volume of a history of In describing these episodes, Mrs. Gowmg gives us a the U.S. Atomic Energy Commission. But in the absence glimpse of the human reactions behind the official fanade. of historical records, achievements in the other nations We learn, for example, how "shocked" the British were have been neglected. Now we have Mrs. Gowing's to receive James Conant's memorandum of January 1943 splendid volume, which fills an indispensable part in the outlining a restrictive policy for interchange, how

"bewildered" they were by the American charge that the latter, and it is to these that he quickly turns following Britain's desire for interchange was motivated by an a brief review, on conventional lines, of various aspects of interest in post-war commercial applications of atomic the internal field. energy. We see for the first time the full dimensions of The systematic 'solar daily' and 'lunar daily' variations Prime Minister Churchill's dissatisfaction with the efforts are first summarily dealt with. Their accepted physical of Prof. Niels Bohr to initiate with the Russians some explanation as a type of dynamo action, produced by frank discussion of international control of atomic energy; diurnal motions of the conducting high atmosphere across and we have here, incidentally, the first public release of the Earth's magnetic field, is outlined. The complicating the full text of the Hyde Park aide-memoire, expressing factors of a vertical component of electromotive force the concern of Roosevelt and Churchill that Bohr's (atmospheric tidal motion) and of anisotropy of iono activities might result in a leak of information to the spheric conductivity caused by the presence of the Earth's Russians. field are also briefly discussed. All this new information will prove invaluable to his The book is primarily concerned with the sporadic torians and others who wish to understand the Anglo ('disturbance' or 'storm') variations. The author reviews American atomic alliance with its problems and accom their categorization and analysis, their representation by plishments. It is essential in evaluating the British atmospheric electric currents and their relationship with contribution to the war-time programme. What is more, solar activity. He also discusses the physical process of Mrs. Gowing tells her story well, with an engaging frank emission of a solar particle 'stream' (in his nomenclature ness and reserve. a long-lived process from a disturbed solar region) and In comparison with these attributes, any criticism will of a 'shell' (short-lived, in association with a solar flare) seem petty. I cannot help but mention the lack of source and the geometrical and thermal expansion to which these citations from Government files. Their absence is the are subject as they move outwards from the Sun. Two price the author had to pay for writing contemporary points, in particular, appear worthy of comment. First, history. The result is worth the price, but we may well a two-page account is, at Chapman's request, contributed ask whether the mere citation of documents need be by C. E. R. Bruce outlining his theory, which is sharply considered a violation of the fifty-year rule applying to opposed to orthodox astrophysics thinking, that solar Government documents. The absence of citations will streams "are continuously generated from the gas of the make it almost impossible to determine the documentary Sun's atmosphere all the way out from the Sun by the basis for somo of the author's most interesting conclusions magnetic pinch effect of the electrical discharge". Second, even when all the evidence has been made public. it is a matter for surprise that Prof. Chapman should The opening chapter , a summary of research in nuclear consider that the systematic annual variation of the physics prior to 1939, lacks the historical style and incidence of magnetic disturbance is caused by changing judgment which Mrs. Gowing brought to the rest of the orientation of the Sun relative to the Earth ('axial theory') book. Doubtless it would have been better history if rather than of the Earth relative to the Sun. Reasons for Mrs. Gowing had undertaken this difficult assignment this surprise may be briefly stated. The statistical evidence herself, if, indeed, such a survey was necessary at is to the effect that maximum disturbance coincides with all. the two equinoxes and not with the dates, earlier than More important is the matter of perspective. Mrs. the equinoxes by more than two weeks, which are Gowing has dono exceedingly well in presenting events required by the axial hypothesis; a parameter with a from the British point of view. But at times she soems semi-annual variation of appropriate phase which may, to be pursuing her objective too resolutely as if she were plausibly, affect the incidence of disturbance is the angle determined to highlight events in Britain even when they between the Sun-Earth line and the geomagnetic axis; were overshadowed by developments elsewhere, particu since this angle also varies diurnally, a Universal Time larly in the United States. This is not a question of component of disturbance would then be implied; such distorting facts but rather of missing an opportunity to a diurnal component (smaller in amplitude than the local paint on a broader canvas. P erhaps to ask moro of one time component) has been identified in all latitudes and book than Mrs. Gowing has done is to be unreasonable. has precisely the required phase. The straightforward She has given us the British perspective on the early inference is surely to the effect that magnetic disturbance history of atomic energy; the larger story is still t o be over the Earth as a whole is greatest, seasonally and written. RICHARD G. HEWLETT diurnally, when the direction of incidence of solar streams on the dipole axis is closest to the normal and is least when the incidence is most oblique to the axis. The remainder of the book, about one half, is devoted SOLAR PLASMA AND to a theoretical discussion of the interaction between a neutral stream of charged solar particles and the Earth's GEOMAGNETISM field. Tho phenomenon is extremely complex and there Solar Plasma, Geomagnetism and Aurora is fundamental disagreement among specialists as to the By Prof. Sydney Chapman. (Documents on Modern relative importance of various factors. Chapman is, Physics.) Pp. 141. (New York and London: Gordon and however, not concerned h ere with a discussion of the Breach, 1964.) Paper 1·95 dollars; cloth 5·95 dollars. relative merits of such opposing views. In one chapter he gives an exposition of the way in which mainly he and HIS book is based on lectures given in 1962 at the associated workers-notably V. C. A. Ferraro-have over T Houches Summer School of Theoretical Physics. a period of more than thirty years approached the prob As the author states in his preface, it is not the first lem of the 'initial phase' of a storm (a sudden increase of appearance of the m aterial in print. The editors of the horizontal force at the beginning of the storm, persisting series D ocuments on Modern Physics were, however, no for some hours). The calculations relate, for example, doubt anxious to make available to their readers this to the effect of electrostatic forces on the motion of the work of so great an authority, in his own field, as Prof. solar gas; to the degree of retardation suffered by the Chapman. particles which most directly approach the Earth and There is a natural division, in geomagnetism, between the distance from the Earth at which this occurs; to the that part of the field which is of internal origin and which rate of growth of t.he disturbance field and the magnitude changes only slowly, and the very much smaller part of the electric currents involved; and to the shape of which is external in origin and which varies on a much the hollow formed in the plasma by the Earth's field. shorter time scale-the so-called 'transient variations'. Although the theoretical work relates, of necessity, to The author's work has very largely boon concerned with highly idealized model problems which exclude many of