human touch as is well evidenced in several places (e. g., see p. 395 onlithium salts; also p. 241 onozone). I n theearly chapters, before the author is ready t o give the chemical details of certain methods involved, he prevents the student having heart failure by the use of "a suitable method." Appropriate employment is made of editorial "we" which is more likely to cause the student to feel that he is really having a rBle in the course. The student's interest is of a necessity aroused by (P. 192) "We must now resume our study of the elements and their more important compounds. I n what order shall we take them?" and (p. 51) "But how can we find this (atomic weights) . . out?" The presentation and frequent utilizations of "soluhilitv. madud" are deserving of com. mendation. The 374 questions and problems will require quite a little cogitation on the part of the user. Although certain chapters, such as the ones on formulas, equation writing, valence, and atomic theory, are introduced earlier than in some texts, their presentation is done in such an unostentatious manner that the student is not likely to be frightened. The material on radium and radioactivity is properly a part of the study of the atom and the periodic law. The absence of a definition or discussion of such terns as allotropes, peroxide strutt u x , amphoteres, and condensed acids may he meritorious. CSz is named "carbon hisulfide" and BaOe, "barium dioxide (peroxide)." The treatment of valence (p. 74-5) is inadequate. The writer is not in sympathy with the author's use of =, +and in equation writing, believing that the former should he in the discard. I t is to be regretted that the effortsof the American Chemical Society are not supported in the spelling of sulfur, aluminum, pipet, and buret. The distinction between "charts" and "figures" is inconvenient to the reader. An appendix of certain physico-chemical tables, particularly of atomic weights, would not be unwelcome. The book is worthy of better executed drawings. The eleven illustra-
tions of chemists are extraordinarily good and suitable for framing. A few cuts showing the commercial side of chemistry would be worthwhile. Some of the descriptive material should he in smaller type. The author has been fairly successful in avoiding a compendium. Despite the above shortcomings, the hook as a whole compares favorably with the better known first-course texts of chemistry. J. E.DAY Atomshuktur und Atombindung. J. STARK. o. Universitat professor fur Physik. Polytechnische Buchhandlung, A. Seydel, Berlin, 1928. First edition. xx f 198pp. 16 cuts. 14 X 22cm. Rm. 9. This hook presents an exposition of a very comprehensive theory, developed by the author, concerning the structure of atoms and the linking of atoms in molecules. Many will feel much in sympathy with his assumption of a static atom that is static in that the central points of the electrons have fined positions. Few will find fault with his claim that the atom possesses an axis, in fact, not only the atom but each electron and proton (archion). He finds i t unnecessary to postulate an ether hut he does surround electrons and protons with electrostatic and electromagnetic fields and endows them with "inner kinetic energy." As a resultant of the electromagnetic, electrostatic, and inner kinetic forces, certain discrete equilibrium positions result. If only slightly disturbed, the electron returns t o its equilibrium position but with a great enough disturbance it may fall to another equilibrium position, the energy difference between these positions heing disposed of quite in accord with the quantum theory. The electrons are built up in layers around the nucleus in a fairly conventional fashion except that the layers possess certain eccentricities peculiar t o this theory. The eledrons of the outermost layer constitute the valence electrons. The nucleus is built, much in the same
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fashion as the electron shell, out of succeeding layers, not of electrons, but of individuals termed "helions" consisting of one electron and two protons (archions) each. These are not stable in free space but only in the strong force fields within the nucleus. Whatever satisfaction one may feel a t the fixed location of the atom constituents is shattered when one comes to the explanation of isotopes and radioactive phenomena. I n the powerful electromagnetic field in the space between nucleus and inner layer of electrons (zwischenraum) still another kind of individual, the neutron, consisting of one electron and one proton, may exist. Of the neutrons there may he any number within wide limits and they are all in rapid and disorganized motion. In their chance collisions are found the causes of radioactive phenomena and in their varying number the cause of isotopy. The most astonishing feature of the author's theory concerns the linking of atoms: a valence or outer shell electron from each atom takes a coaxial position with respect to the other so that the two valence electrons fall in a straight line connecting the two atom nuclei. The author realizes that the electrostatic repulsion of the electrons would seem to make such an arrangement impossible, but he presents arguments to show that in the equilibrium positions this farce would be counterbalanced by attractive forces. The author complains rather bitterly a t the dogmatic manner in which many theorists build on arbitrary assumptions which could never have reality. His own assumptions follow, he claims, naturally and unforced from experimental facts. He gives no details of mathematical analyses t o prove his viewpoints although a t times he expresses his arguments in mathernatical langunge. It is however not beyond the hounds of possibility that the author has committed the same error he denounces in others. Some of his assumptions seem to be not only arbitrary but unreasonable and a careful reading of his
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arguments does little to counteract that impression. The value of a theory of the structure of matter rests in its usefulness in classifying facts of observation and predicting new facts and the more diverse the classes of facts thus brought together the more valuable the theory. The author's unsurpassed acquaintance with such properties of substances as magnetic susceptibility, dielectric constant, frequencies of emitted and absorbed light, etc., place him in a position t o measure the serviceability of a theory with respect to such facts. He likewise offers quite a wealth of chemical fact in support of the adequacy of his theory. Unfortunately, however, very little is first-hand fact of observation. I t is rather the conclusion from observation stated in the language of theories of doubtful comprehensiveness. He speaks of valence and changes in valence with assurance, perhaps not realizing that no chemist has ever formulated a satisfactory definition of valence. The value of this very comprehensive and painstaking work of the author lies in showing the fallacies of some of the current theories and in its suggestiveness as t o starting points in building a completely serviceable theory. Some of the baffling physical properties of matter are made in some respects more comprehensible by the author's theory but the chaotic facts of chemistry are by no means brought as nearly into an orderly system by it as by other of the modern theories. ARTHURA. BLANCHARD Vestiges of Pre-Metric Weights and Measures Persisting in Metric-System Europe, 1926-1927. ARTHURE. KENNBLLY, Professor of Electrical Engineering a t Harvard University. The Mamillan Co., New York City, 1928. xvi 189 pp. 9.5 X 14.5 cm. $2.50.
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The book is the result of a research with the aid of the Bureau of International Research of Harvard University and Radcliffe College. Professor Kennelly ex-
