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NEW BOOKS
This work deals with metals and alloys, and is one of those typical monuments of German industry and scholarship which not only demand but compel admiration. It begins with a good account of the technical methods of the preparation of alloys, and a comprehensive account of a formal phase rule treatment. The book is full of excellent photographs; the colored ones are especially noteworthy. From the point of view of the practical man the book is of the greatest interest. There are excellent photographs, for example, in the section on brass, of the serious technical defects which arise through the use of wrong temperatures. The references to the literature are numerous, and the reviewer, who has checked about twenty, has found them all correct. It is difficult to see how anybody interested in non-ferrous alloys can afford to be without this book. F. A. FREETH.
Veroflentlichungen aus dem Kaiser Wilhelm-Institut f i i r Silikatforschung i n BerlinDahlem. Edited by Wilhelm Eitel. 29 x 21 cm.; 212 pp. Brunswick: Friedr. Vieweg und Sohn, 1932. Price RM.28. The proceedings of this active Institute again cover a wide range. Working as it does in close cooperation with the silicate industries, it has been found necessary t o widen the scope to include the study of the heat balance in technical processes, such as the manufacture of Portland cement. I n this connection a description is given of the new ‘Lepol’ kiln, which although of German design has so far been erected only in Spain and in Luxembourg. By the use of a preliminary roasting chamber utilizing the waste heat, the actual kiln is greatly shortened, and a very considerableeconomy of fuel is effected. Other work on cement includes a study of the setting time of mixtures of Portland and aluminous cement, from which it appears t h a t the properties of the mixtures are not additive. Glass problems fill the greater part of the volume. With the help of the German glass manufacturers, a set of tables of the properties of glass, taking into account some 2500 publications, is in course of preparation. These tables will include the chemical as well as the physical properties. Several communications deal with the removal of color from glass, especially b y means of cerium. Cerium dioxide is superior for this purpose to manganese dioxide, but it will cause darkening by ultraviolet light if arsenic or bismuth be present. This effect is corrected b y the addition of small quantities of sodium sulfate, and the mutual influence of these additions is worked out. I n opal glass, the crystals producing turbidity are identified as cristobalite, whatever the composition of the glass, although in fluoride glasses the presence of minute crystals of sodium fluoride has also been proved. The hydrothermal synthesis of calcium silicates and the action of carbonic acid under high pressure on the silicates have been studied, one result being the preparation of definite carbonatesilicate glasses, containing as much as 20 per cent of sodium carbonate. This memoir includes an interesting series of quantitative experiments on the equilibrium between carbon dioxide and glasses. The flow of molten glass in the Owens machine is considered theoretically, this paper t o be followed by one in which the theoretical deductions are to be tested by an examination of the flow lines as shown by Schlieren. As in previous years, there are several descriptions of improved apparatus and experimental methods, and a few communications having only an indirect bearing on the silicate industries are included, such as a study of vanadium oxide sols and another in which the dehydration and rehydration of brucite is examined, it being shown that a new phase is formed, and not simply a pseudo-structure. The editor is to be congratulated on the quality of the work done under his direction, and on the excellent presentation of i t in this handsome volume. C. H. DEBCH.
