VOL.7, No. 5
RECENTBOOKS
Colloid Symposium Annual. Volume W. Edited by Dr. H. B. WBISER,Professor of Chemistry a t the Rice Institute. John Wiley & Sons, Inc.. New York, 1930. 23 X 15 cm. viii f 300 pp. 127 figures. $4.50. This book, formerly called the "Colloid Symposium Monograph," contains dl the papers presented a t the Seventh Symposium on Colloid Chemistry, held a t the Johns Hopkins University, June, 1929. Titles of the papers and authors are as follows: 1. "The Scattering of Light in Sols and Gels." P. G. DONNAN and K. KarrHwAxuarr.
2. "The Structure of Gelatin Sols and Gel.." S. E. Saep~ARoand J. G. MCNALLY. 3. "The Measurement of Hvdratition of Gelatin and Similar Materials and t h i Relation of Hydration to Swelling." HARvBX A. NBYlLLE and Enwrn R. Tnsrs. 4. "The hauence of Adsorption on the Grovth of Crystal Surfaces." K A R L P. HBnz-
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23. "Adsorption and the Permeability Membranes." H AB.WHISER. ~
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The established tradition of excellence and variety in the papen presented has been continued in this volume. One cannot read many of them without receiving inspiration for work in this important field. A detailed review of such a compilation is scarely practicable. Inclusion of the discussion on each paper might be an improvement. However, the reviewer wishes to congratulate the publishen and the editor on their successful effort. Every colloid chemist will want to add this volume of the annual to his set. MALCOLM M. HARING U N I M I ( S I01~ 1 MARYUND COLIBOBPA=,MD.
Diatomaceous Earth. ROBERTCALVERT, Chief Chemist, Van Scbaack Bros. WLD. 5. "Crystal Structure and Adsorption from Chemical Works, Chicago (formerly in so:. ut~on." '..s tgnrecance .WBSLBVG. of FBANCH. the Eleetro~apillary Charge of Research Labaratow, The curve.,; A. Pnurnrr. Celite Company, Lampac, California). 7. Determinatmn of the Number of Free Electric Charger on Air Bubbles and Oil Droplets American Chemical Society Monograph Dispersed in Water Containing a Small Amount Series No. 52. The Chemical Catalog of Cetyl Sulfonie Acid." JAMBS W. MCBAIN and ROBERTC. W I L L ~ ~ S . Cbmpany, Iuc., New York City, 1930. 8. "The Electrostatics of Plotation." H. B. xiii z;il pp. 70 figs. 15 X 23 cm. BULL. 9. "Some Evidence on the Nature of ExtraMolecular Forces." DONALDH. ANDRBW. 10. "The Adsorption of Vapors;' WALTBE A. P A m C K . 11. "The Specific Surface, Area of Activated Carbon and Silica." F. E. BARTBLL and Ylwo
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$5.00. This authoritative work on diatomaceous earth will be welcomed by all who have to do with this interesting and relatively abundant natural resource. Owners of diatomite deposits will be able to make some comparisons of their own material with that from other sources and to learn something of its uses and of the market conditions affecting its commercial exploitation. They will also discover that the successful development of their deposits and the marketing of the resulting products are dependent on the degree to which they are able to control these operations by thorough-going scientific research. Representatives of the various industries that involve filtration, heat insulation, concrete manufacture, and a wide variety of other activities will here find summarized with appropriate tables and graphs the results of much original experimental work dealing
