NEW BOOKS Disperse Systems in Gases; D u s t , Smoke, and Fog. A general discussion held by the Faraday Society, April, 1936. 25 x 16 cm.; pp. 1041-1300. London and Edinburgh: Gurney and Jackson, 1936. Price: 12s. 6d. This book is a report of the meeting held by the Faraday Society in Leeds in 1936, a t which the many aspects of disperse systems in gases were discussed from various points of view. The report includes all the papers contributed to the meeting, together with the discussion thereon, and in it much detailed information is assembled in such a form that the reader can obtain from this one source a thorough knonledge of recent developments in this field of investigation. The subject is considered under two main heads, viz., the general properties and behavior of disperse systems, and the industrialaspect of such systems. Subdivision of the first part is made into disperse systems composed of solid and liquid non-volatile particles (smoke, dust, oil, fogs, etc.) and those consisting of aqueous and other volatile particles (mist, cloud, hygroscopic nuclei, town and country fogs). The first of these subsections includes such matters as methods for determining the number of particles in smokes and size distribution in smokes and mineral dusts, the dust-free space surrounding hot bodies, and cohesion between smoke particles. The effects of such influences as pressure temperature gradients, sonic and supersonic vibrations, and ionic currents are also discussed. The second subsection deals, amongst other matters, n i t h the nature of dispersoids in country and t o n n air, the determination of the mass and size of atmospheric condensation nuclei, hygroscopic nuclei in the formation of fog, sorption of fog by liquids. sulfuric acid mist, and n i t h the removal of mist by centrifugal methods. The industrial section contains papers on the inflammation of dust clouds, the spread of smoke and gases from chimneys, the dissipation of fog, the physical basis of electrical gas purification, and the physical and chemical problems involved in the design of a plant for removal of smoke and oxides of sulfur from flue gas. This section also includes a n interesting paper on tffenty-five years' progress in smoke abatement, n hich deals with air pollution records of some twenty-three centers in Great Britain. I t is very pleasing to have available in one volume such a comprehensive treatment of this extremely varied subject, and in a form in Tvhich there is so much of interest both to the pure scientist and to those n-ho seek to apply in industry the physicochemical principles involved. H. W ,CREUER. Die Chemze der naturlichen und kunstlzchen organischen Farbstoffe. By G. Schiemann. 20 5 x 13 cm.; viii 136 pp. Leipzig: Leopold Voss, 1936. Price: 7.20 R X The author of this introductory survey of the theory and practice of color chemistry is to be congratulated on tahe selection and arrangement of the material. This admirable book a t reasonable cost is eminently suitable for chemists to obtain an outline of the chemistry of coloiing matters or to avoid pitfalls \Then they use dyes in their researches. T h e subject is treated a s a n-hole b y including natural and synthetic coloring matters together in the appropriate chapters which are arranged according to the com1227
+
