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multicomponent systems, while the chapter on distillation and condensation treats simple distillation, batch distillation, vacuum and steam distillation, and azeotropic and extractive distillation. A chapter on adsorption completes this section of the book. Equipment, operating variables, and methods of calculation for ideal stages are outlined. I\‘. Energy and Mass Transfer Rates: “The time rate with which energy or mass is transferred from one stream t o another determines the size of equipment required t o accomplish a specified result in a specified time. The rate of transfer equals the product of a “transfer coefficient,” “the area of contact,” and “the drop in potential.” The first five chapters in this section comprise heat transfer and evaporation. After introducing the subject by describing heat transfer equipment, the theory and formulation are outlined for steady-state and unsteady-state conditions. Discussion of transfer coefficients between fluids and tubes includes fluids of high conductivity, such as molten metals. The subject of condensing vapors and boiling liquids is handled in a n interesting manner, and is well illustrated in a brief but adequate way. A consideration of radiation and radiant heat transfer completes this portion of the book. The chapter on evaporation follows a conventional pattern, but the discussion of heattransfer coefficients in evaporation is quite brief and might be amplified. The chapter on crystallization is brief, and more emphasis might be given t o the discussion of crystallization rates. A short chapter on agitation serves as a n introduction to this subject. The last four chapters of the book deal with mass transfer. “Mass Transfer. I” shows the analogy between momentum, heat, and mass transfer. “Mass Transfer. 11” gives coefficients in packed towers and treats gas-phase coefficients, distillation concepts, and liquid-liquid extraction coefficients. Adequate sections on psychrometry and drying complete the treatment of mass transfer. This book will be welcomed by all engineers who appreciate well-written authoritative statements of the principles of unit operations, with suggested practices all neatly tied together with graphs, charts, tables, and illustrative problems. GEORGEH. MONTILLON.
New Atoms. Progress and Some Memories. By OTTOHAHN.184 pp. S e w York: Elsevier Publishing Company, 1950. Price: $1.75. This account of the past fifty years of atomic science and radioactivity by the distinguished discoverer of fission has an interest not only to those directly engaged in this field but also t o all who will welcome a personal account of one of the greatest-if not the greatest-discovery of all times. For surely none can doubt, the influence of atomic fission on science and on all human affairs. Hahn’s approach t o the subject is a simple factual one. The papers comprising the volume, as edited by Dr. W. Gaade of Amsterdam, are divided into four parts. The first is the address which Hahn gave on the occasion of the belated award of the Nobel Prize t o him in 1946. I n this address he reviewed his long and careful series of investigations, following t h e initial work of Fermi, which convinced Hahn and Strassman that barium is produced by bombarding uranium with neutrons. At the same time full credit is given t o Meitner and Frisch for the elucidation of the process and for the introduction of the term “fission.” Winnowed from the mass of experimental details this account has a clarity and direct sequence which naturally the original German papers lacked. The second section on the chain reaction of uranium carries the subject from the first experiments of Rutherford on artificial transmutation, through artificial radioactivity of Joliot-Curie and the discovery of the neutron b y Chadwick t o plutonium, uranium 235, t h e chain reaction and its application in power reactors and the bomb, with brief reference t o the hydrogen bomb. Some duplication of part of the first section is unavoidable. The third part, on artificial elements, is divided into two categories: the four elements (43, 61, 85 and 87) which fill vacancies in the periodic system below uranium, and the six (93 t o 98) transuranium elements. This section will be especially prized by the busy reader,
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for in a few pages and a hhlf hour’s time he will find information about these interesting new elements that could require days of search in the original literature. Hahn brings them all down to earth and into the family of preesisting elements. With reference t o a new series of rare earths he supports the view of Seaborg that the series begins with actinium, in spite of the higher valences of protoactinium, uranium, and neptunium. I n the closing section of thirty delightful pages Hahn reverts to happy days with Rutherford and Ramsay in hlontreal and England, and describes some of his early discoveries of riaturd radioactive elements. S o living man has so successfully spanned the world of discovery from radiothorium to fission. As Hahn says, it is “a long road from the alchemist’s dream t o the transmutation of many elements-one is almost inclined t o say-in any desired quantity.” And it is a far cry from the tin can electroscope t o the photomultiplying scintillation counter or from the Curies’ open shed a t the &ole Normale in Paris t o the plutonium piles on the bleak plains of Hanford. Yes, a long road and who can say where it leads or ends. S . C . LISD. Structure of Molecules and the Chemical Bond. By Y.K. SYRKINASD 31. E . DYATKINA. Translated and revised by M.A . PARTRIDGE ASD D . 0. JORDAN. 24 x 14 cm.; ix+509 pp. London: Butterworths Scientific Publications, 1950. Price: f3-3s. The excellence of this book in the original Russian has been recognized and the appearance of a translation, with revision in parts where this was necessary, is welcome. The book aims at giving a readable yet thorough account of its subject, and i t seems to fill a place not occupied by other books. The mathematical treatment is much fuller and more intelligible than is usual in books intended to interest chemists, and for this aspect alone the book will be invaluable. At the same time the needs of chemists have been met in the detailed discussions of matters of chemical interest. There are full references. The first chapters deal with atomic atructure and Ivave mechanics, a very thorough and detailed treatment being given, although a mathematical appendis deals with many topics treated more generally in the main text. The subject of resonance is then treated in relation to various types of bond structure. The method of molecular orbitds, spectra, dipole moments, bond energies, van der Waals forces, and crystals are nest esplained in detail. The complex compounds and the boron hydrides (this section having been revised) then introduce material of definite chemical interest, when the three-electron problem treated by Slater’s method and the polyelectronic problem and resonance energy come in. The reviewer believes that this book is the best introduction available to students and teachers and can heartily recommend it. I t makes clear many things not dealt with in others, and does not shirk the mathematical foundation of the subject. J. R . PARTIXGTOS. Geochiinica el Geocosrnica Acta. Vol. I , ? i o . 1. London: Butterworth-Springer, Ltd., 1950. Price: E3-10s per volume. The aim of this new journal is t o publish original papers on the subjects named in its title, which have previously been distributed over several different journals of varied interests. The editorial board includes authorities from various countries, the editors being C. W. Correns (Gottingenj, E. Ingerson (Washington), S. R . Sockolds (Cambridge, England), F. A. Paneth (Durham), L. R. Wager (Oxford), and F. E. Wickmann (Stockholm). The high quality of the journal is thus assured. The first number contains papers in English and German and a report of the International Commission on Meteorites. Chemical interests are well represented in this number by papers on the carbon and nitrogen in subaqueous sediments, the determination of argon in potassium minerals, the analysis of stony meteorites, the origin of sodium bicarbonate waters in the Atlantic and Gulf Coastal Plains, and the calcite-wollastonite equilibrium. Physical chemists should find much t o interest them in this new journal, and its appearance can be welcomed. J. R . P.ARTINGTON.
