In addition, methods for identifying the ions, provided they are adequate, are of the same nature as those employed in the macro methods. Wherever these methods are found to be inadequate, more sensitive tests involving organic reagents are used instead. The confirmatory tests make use of such reagents almost exclusively. The technic of working with a drop or a few drops of solution has been highly developed by Feigl and co-workers; it is !mown as the "drop-reaction" technic. The microscope is not required here. However, a small hand centrifuge is used t o carry out precipitations, while the supernatant liquid is removed with a capillary pipet. Spot plates, both white and black, are also used for e nrerinitation orocesses. Small funnels. suction flasks and ~.. - ~ ~ ~ . ~ - ~ ~ test-tubes, and ordinary medicine droppers make up an important part of the equipment. Organic reagents are used for the more sensitive tests but none of these is absolutely specific: group separations and the elimination of interfering ions must first be accomplished. The text is divided into four parts: (I) Fundamental Principles of Qualitative Analysis, (2) The Reactions of the Cations, (3) The Reactions of the Anions, and (4) Systematic Microanalysis. The first part contains the usual treatment of the law of chemical equilibrium, ionization, solubility-product principle, hydrolysis, amphoteric substances, complex ions, oxidation and reduction, and the structure of molecules. It comprises about 100 pages of the text. It is unfortunate that strong electrolytes are treated as being partially ionized and thereby capable of contributing to the displacement of ionic equilibria. Part 2 includes a discussion of the chemical properties of the positive ions, various tests for each ion, including inorganic as well as organic reagents, methods for carrying out the tests, and procedures for practice analysis of the different groups. The semimicro technic is stressed throughout this section. It is gratifying to see that there are made available t o the student several tests for each ion. This section also includes numerous references to the literature concerning spot-reaction tests, the use of organic reagents, and the elimination of interfering ions. The following anions are included in Part 3: nitrite, cyanide, sulfide, thiosulfate, sulfite, carbonate, arsenite, arsenate, phosphate, silicate, fluoride, chromate, sulfate, borate, oxalate, tartrate, ferricyanide, ferrocyanide, thiocyanate, iodide, bromide, chloride, nitrate, and acetate. The semimicro technic is likewise stressed in this section. Part 4 describes methods of procedure for the preliminary examination of the unknown, systematic cation analysis, systematic anion analysis, and the analysis of insoluble substances. The Avpendix gives the following tables: atomic weights, .solubility of inorganic salts, periodic system of the elements, composition of test solutions, lists of apparatus, and methods for the preparation of liquid reagents of all types. The text is remarkably free from errors and appears in wellprinted form. The authors are t o be congratulated on the initiation of a text of this type. Without doubt the teacher of qualitative analysis will receive from it a fresh point of view and renewed inspiration in the presentation of the laboratory work: Certainly, the student will show a greater interest and thereby benefit considerably in the application of the semimicro technic his laboratory problems. WARREN C. JOHNSON ~~~
CHIC*^^ C A I C A T ~~, L L ~ N O ~ S
UN,Y*RS~TY OX.
COLLOIDS - O S ~ MONOGRAPH. Papers Presented a t the Twelfth Symposium on Colloid Chemistry, Ithaca, New York, June, 1935. Edited by Harry Boyer Weiscr. The Williams & Wilkins Company, Baltimore. 1936. 156 pp. 17 X 25 cm. 83.00. The contents are as follows: The Constitution of Hydrous Oxide Sols from X-ray Diffraction Studies. Harry B. Weiser and W. 0 . Milligan. Electrokinetics. XVI. Streaming Potential in Small Capillaries. Henry B. Bull and Laurence S. Moyer.
Studies on Silicic Acid Gels. VI. Influence of Temperature and Acid upon the Time of Set. Charles B. Hurd. X-ray Spectrography of Alkali Celluloses. John B. Calkin. The Oxide Film on Passive Iron. Wilder D. Bancroft and J. D. Porter. The Phase Rule in Colloid Chemistry. Wilder D. Bancraft. The Determination of Contact Angles from Measurements of the Dimensions of Small Bubbles and Drops. 11. The Sessile Drop Method for Obtuse Angles. Guilford L. Mack and Dorothy A. Lee. Adsorption a t Crystal-Solution Interfaces. IX. The Concentration of Foreign Substances in Solution Relative to the Quantity Adsorbed by the Host Crystal. Wesley G. France and Phoebe P. Davis. Spectroscopic Estimation of Adsorbed Ions. May Annetts and Lome Newman. Vapor P r e s s u r t W a t e r Content Relations for Certain Typical Soil Colloids. Lyle T. Alexander and M. M. Haring. Stream Potentials and D. C. Surface Conductivities in Small Capillaries. H. L. White, Betty Monaghan, and Frank Urban. Adsorotion bv Diatomaceous Filters. Earl 1. Hoaeland - and John E. kutzler; Jr. Adsorption and Diffusion in Zeolite Crystals. Arne Tiselius. Dynamic Dispersions and Emulsification. C. H. M. Roberts. The Adsorption of Water Vapor by the Growth Elements of the Sapwood and by the Heartwood of Southern Pine. C. J. Frosch. A Hydrate Decomposition Mechanism. V. R. Damerell and 0. F. Tower. Omo REINMUTH P n o s ~ m ~ B~cponis. ru DAWNOF THE ALMHOLERA.William J.Hale. The Stratford Company, Boston. 1936. ii f201 pp. 13 X 19 an. $2.W. The passing of the petroleum era and the beginning of the alcohol era is the main thesis of this interesting and thoughtprovoking book by Dr. William J. Hale. Under a scientifically controlled social and economic system, which the author calls "chemeconomics." the end of unemployment is visualized with the transfer of millions of workers to the farm. Dr. Hale regards the modem chemical revolution as of even greater significance than the industrial revolution of a centurv am. He condemns roundly the modem devices of limiting production to raise prices as false recovery under a "famine-dole" system. The production of food and raiment, now the major concern of agriculture, the author thinks will be of lesser magnitude in the future than the growing of raw materials for industry. Alcohol is to be thelargest single product of agriculture. Dr. Hale regards alcohol as an ideal motor fuel, to b e gradually substituted for gasoline. I t isalso to be thestarting substance for many synthetic nrodncts. The carbon dioxide evolved in fermentation is t o be r~ applied to plants growing in fertilircd damp roil under transparent sheets of ~ ~ t l l ~arctate d o . ~ or 4milar material also dmrrtl from a g ~ i w l t ~lloth r ~ . for incrcasinp yi:lda and rendering the farmer independent of dimatic extremes. Dr. Hale believes that under the chemecanomic system foreign trade in organic materials would become comparatively insignificant. He advocates national self-sufficiency, arguing that it is expensive to transport farm products which are mainly carbon dioxide and water. He believes strongly in profit as an incentive to industry and progress, but urges larger participation of labor in corporate ownership. The book is written in a popular and entertaining style. The treatment is not detached and objective, the author being a frank and vigorous advocate of chemurgy, chemeconomics, and the alcohol era. Chemists will find this book inspiring in the vision it brings of greater opportunity, and business men d l find it valuable for the idea of a new economic system based on the chemical transformation of farm products into the articles of industry. W. T. READ
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