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introduction of terms etc. are all dealt with in a satisfactory manner. The Bohr hydrogen atom model forms of course the background of the discussion. Its extension to many electron atoms, the shell model of the atoms, x-ray spectra, the empirical arrangement of terms, selection principles, the need for four quantum numbers for a complete description of the energy state of an electron, the Pauli principle, the formal model of an atom with several valency electrons and the wave mechanical model of the atom are developed in this section. Part I11 is the longest section (100 pages) of the book and contains material every chemist should be familiar with. The next portion of the book, (Part IV) “The development of the periodic system,” shows the construction of the various elements as far as the arrangement of the electrons into various shells or states is concerned and it also gives the normal state of the eIement in the modern notation. Part V, “The periodicity of chemical properties,” contains a discussion of chemical valency, ionic and atomic binding, the Haber-Born cycle, ionization potentials, electron-affinities, forces acting between ions, ionic radii, lattice energies, and Heitler-London theory of non-polar valency. It is seen that only the simpler structures are treated. The coordination compounds, which form a very large class of substances, are not dealt with. The systematic arrangement of the electron structures of the elements which is obtained from spectroscopic theory evidently appeals to the authors very much and the reviewer certainly shares their attitude. But in their enthusiasm they are willing t o place helium in the periodic table (table 38) into the second group, because helium has the electron arrangement sz, lS,which is also the arrangement for the valency shell of the alkaline earths! But the outer pair of electrons in the alkaline earths is held so much more loosely that these metals have nothing chemically in common with the rare gas-like helium! However, the reader of the book will certainly obtain a picture of the periodic table based on modern physical theory, and to chemists who wish to keep abreast of the modern development of the fundamentals of their science and to the younger generation who wishes to obtain this basic knowledge the book can be heartily recommended. GEORQEGLOCKLER. L’atomistica moderna e la chimica. By M. Haissinsky, edited by U. Hoepli. 307 pp. Milan, 1930. Preface by N. Parravano, Director of the Chemical Institute of the University of Rome. The author covers the whole field of modern atomistics from the physical and chemical angles and necessarily he must be brief within the space of the book. The treatment is therefore most concise and whenever mathematical formulation is desirable or necessary he contents himself to state relations in mathematical terms without showing their derivation from more fundamental principles. It is really astonishing that he succeeds in covering such a mhltitude of topics in such limited space. But he certainly does succeed, and the book gives the Italian chemist a complete view of modern knowledge and theory of atomic structure and the bearing these notions have upon chemical principles. The twelve chapters cover the following topics: I. Molecules, atoms, and electrons. 11. Thermodynamics and quanta. 111. The Atom of Bohr. IV. The electronic theory of valency. V. Born’s theory of grating energy. VI. Applications of Born’s theory. VII. Electric charge, atomic radii, andelectronic structure. VIII. Deformation of electronic orbits. IX. Photochemistry. X. Photochemical theory. XI. Catalysis and adsorption. XII. Wave mechanics and Fermi statistics. But this resume does not give even yet all of the material covered, for each chapter consists of many subdivisions, and i t appears that no topic has been left unmentioned that may have some connection with modern atomic and molecular theory. However the Raman effect is not mentioned, although it was discovered in the year 1928.
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Each chapter contains a t the end a bibliography of the important articles, books, monographs, and treatises of the material covered in that chapter. An author index is appended but no subject index is included. However, the table of contents is very complete with many subdivisions and the reader should not have undue difficulty in locating a desired subject in the body of the book. While of course the same material is covered in many treatises, i t will appeal to the American chemist of linguistic tendencies t o study the topics involved in the Italian language. GEORQEGLOCKLEQ. translated by Edward S. Allen. New Atom and Cosmos. By HANSREICHENBACH, York: The MacMillan Company, 1933. Price: $2.00. I n our present state of turmoil in science, and in physics in particular-where discoveries quickly follow discoveries, new theories supersede each other in rapid succession, and contradictions are the order of the day-it is refreshing to find a book in which the fundamental conceptions a t issue are so clearly discussed. I n as simple language as is consistent with such a difficult problem, Professor Reichenbach, who holds the chair of Natural Philosophy in the University of Berlin, gradually develops his subject, and shows, first, that it is not merely a “mania for speculation” nor a disagreement upon facts between different observers t h a t has led to the present crisis. Its roots go far deeper, and what is a t stake is no less than a revolution of our entire conception of the cosmos, involving a making over of philosophy, and a revolution as far reaching in its consequences as Copernicus’ break from the Ptolemaic and Aristotelian doctrines. First giving us an insight into the world of the astronomer, the world of space and time, and of great dimensions, then, with the aid of a ray of light and its electrical interpretations, leading us into the realm of atomic physics with its minute dimensions but immense forces, Professor Reichenbach, in a final summing-up, discusses the bearing of all this upon our philosophy of science. It is shown that ours is a world of mediocrity; that our “laws” of nature are laws only insofar as they apply to a world of moderate dimensions; that these laws which give us a semblance of certainty are in reality neither immutable nor even “true,” but only practically so, by virtue of the fact that they represent statistical averages of a gigantic number of separate entities, I n the microcosmos, the world of the atom, there are no such concepts as certainty or causality, while in the macrocosmos, in interstellar space, there is not that geometrical simplicity of Euclid which we formerly ascribed to it. Perhaps one of the best features of the book is that the author develops his argument by actually following the line of reasoning of the physicist and the mathematician, and makes use only sparingly of that now so popular device of analogues, which, though unquestionably simpler and more gratifying to the uninitiated, is so often misleading as well. As a guide into contemporary scientific philosophy this volume of Professor Reichenbach is one of the very best t h a t has come to this reviewer’s notice. The English translation by Professor Edward S. Allen of Iowa State College, maintains throughout a high degree of excellence. The only slip t h a t I have been able to find is on p. 202, where reference is made to the American physicist, C. T. R . Wilson. As stated in the preface the book is an outgrowth of a series of lectures broadcast by the author in Berlin during 1929-30. One must admire equally the skill with which Professor Reichenbach has adapted his presentation to such needs, and the courage of the broadcasting station in unleashing such material on the public, and wish that we could do the same with our enlightened populace. W. J. LUYTEN.
