NEW BOOKS Der disperse Bau der festen Systeme. Allgemeine Theorie der Verunreinigung fester Systeme. By D. BALAHEW.23.5 x 15.5 cm.; vi 240 pp. Dresden and Leipzig: Theodor Steinkopff, 1939. Price: unbound, 7.50 RM; bound, 8.62 Rhf. Theories of the mosaic structure of real, as distinguished from ideal, crystals have been constructed by many writers with the object of arcounting for special properties of solids, surh aB their behavior on deformation or their action on x-rays. The work of I3alarcw is concerned rather with the rhemiral properties of crystals, especially thcir tendency t o retain impurities when separating from solution. The author has carried out many experiments in this field, which he has tlrscribecl i n numrrous papers. His main idea is that a crystal is always built u p of small 111(1rks,often so small that, their composition departs markedly from the stoirhiorntTtric ratio. and that thrse blocks are separated by irregular channels, in whic.li I o w i g n niolwulrs, atoms, or ions are retained. This is described as internal adsorption. If barium sulfate he precipitated in the presence of potassium permanganate, the crystals are colored red, and this color is not removed even by long contact with reducing agents. Other similar examples are described. The formation of suhmicrons when a crystal is i n process of dissolving is also taken as evidence for a block structure. The hearing of such observations on gravimetric analysis is discussed, and means are drscribed for obtaining precipitates with the least possible contamination, internal adsorption being regarded as of greater importance than adsorption a t the free surface. X-ray evidence is referred t o b u t not discussed quantitatively. Again, although reference is made t o the appearance of crystals under the microscope, this method is not applied in any systematic way. The presentation of the author’s ideas involves a great deal of repetition, and the work might have been condensed with great advantage. There are many references t o the literature, but also some surprising omissions. Thus, although mention is made of the action of impurities in modifying the habit of crystals, there are no references t o the work of such investigators as Beudant, Tertsch, and Buckley, although their experiments, especially those of Buckley, have thrown much light on the way in which foreign ions and niolecules are built into the structure of a growing crystal. The general impression derived from reading the book is t h a t the author has rollected many useful observations on crystals which support the view t h a t some kind of block structure is usually present, but t h a t they fall short Qf providing an explanation of t h a t structure. The conrluding theoretical argument is unconvincing. C.H. DESCH.
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Mellor’s Modern I?lorganic Chemisfry. Revised and edited by G. D. Parker in eollaboration with J. \V. hlellor. 6 x 9 in.; xix 915 p p . ; 241 figures; 68 tables. New York: Longmans Green and Company, 1939. Price: $4.50. This is the ninth edition of what has come t o be generally accepted as one of the standard books of inorganic chemistry. The contents have been entirely rearranged and largely rewritten. The first sixteen chapters are devoted t o theoretical material and inrlude: properties of gases; chemical change; molecular t,heory; atomic and 136
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