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NEW BOOKS
NEW BOOKS A p p l i e d Xuclear P h y s i c s . Second edition. By ERNEJT C. POLLAED A N I ) WILLIAM I,. DavtuSON. 352 pp. New York: John Wiley and Sons, Inc., 1951.Price: $5.00. Since the appearance of the first edition of this book in 1942,the field of nuclear physics baa advanced so rapidly that extensive revision and additions have been necessary to bring the present edition down to date a t the close of 1950. The writers fully realize that the application of nuclear energy has not yet reached its goal and that great progress is in prospect both in theoretical and in applied nuclear science. With the liniitations of “security” and of rapid change clearly in mind, the authors have rendered a real scrviee in producing a work which will be most useful to the increasing host of those engaged i n nuclcar research or technology, particularly t o those newly entering the field. The chapter on methods of accelerating atomic particles describes the various types of accelerators with clear diagrams and descriptions. The methoda for detecting :ind studying particles in flight are well presented. Data oil rreutrori cross-sectioirs are eonspicuously lacking. A chapter is devoted to the reactor program of the Atomic liiiergy Commission, in which plans for four new types sre given. The final chapter, devoted to nuclear theory and cosmic rays, describes the present status of this subject in a clear and comprehensive manner especially acceptable to those who have not followed the slow and intricate development of this field over the past twenty years. The last fifty pages contain a number of appendices. The first is a list of soinc of the most important discoveries of the past fifty years. The table of atomic species, while extensive, is not claimed t o be complete. A list of nineteen commonly used r:tdioisotopes gives half-lives and electron and gamma-ray energies. A notable feature is that, with two exceptions (K-131and C-14),all have odd isotopic numbers, which mean8 that if the atomic number is even, the neutron number is odd and vice versa. Appendix 8 presents elementary pile theory in some detail (12 pp.). Seutron d ction is discussed briefly. The final appendix (Appendix 11) contains some ingenious laboratory experiments. The publishers are t o be commended for the moderate price of a book of this length and quality.
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The Identi$cation of Molecular Spectra. Second edition, revised. By It. W . B. PEARSE AND A . G . GAYDOS. viii 276 pp. New York: John Wiley and Sons, Inc., 1950.Price: $8.50. The subject matter for this revised compilation of data on molecular spectra may be best described by the introductory material on the protective paper wrapper: “The ldenti$cation of Molecular Spectra contains photographs of band systems, tables of wavelengths, suggestions for using the tables, and general information about band spectra-all designed t o help the scientist make accurate identifications of molecular spectra in the wavelength region from 10,ooO A. to Zoo0 A. Thefirst part lists the strongest heads of the better-known band systems of each molecule, in order of wavelength, together with information about their origin, intensity in various sources, and appearance. By comparing the strongest band in the unknown baud system with this list the scientist will be able tentatively to identify the system. He call then refer to the s e w n $ p a r t , which includes individual lists of b a d heads for each system of each molecule, plus pertinent notes about the system . . . until positive identilication is made.” There is no doubt that experimental spectroscopists will welcome the publication of this revised edition. I t includes emission arid absorption data on about forty molecules not previously included in the first edition, as well as corrections in identifications (for example, the IlgBr: and HgCI.: emission bands are now ascribed to HgBr and HgCl, respectively). Kxtension of tlie data raises the total ~iumberof pages for the “Table of Persistent Bi111d Heads” from 31 to 36 ],ages, while the more detailed “Tables of Ldividual Band Systems” arc cxlended from 160 pages to 2 8 pages. The section on “Practical
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