VOL.
4, NO. 3
WCENT
A Collection of Chemical Lecture Experiments. H. F. DAVISON. The Chemical Catalog Co., Inc., New York City, 1926. First edition. 139 pp. 23 figures. 12.5 X 19 cm. $2.50 net. In a preliminary note to the reader this little book is gracefully dedicated by L. A. Bigelow to the Teaching Profession as the last work of one who was called only too suddenly from our ranks. Those who were fortunate enough to hear Prof. Davison's paper on "The Art of Lecture Table Demonstrating," delivered before the Division of Chemical Education a t the recent Baltimore meeting of the American Chemical Society, will be particularly interested in the introductory chapter which bears the same title. I n i t the author, a very able demonstrator himself, has given a very clear exposition of the fundamental rules which he believes must be observed. There follow descriptions of 69 experiments, grouped in the index under the titles: Gases (5). Combustion and Oxidation (12), Hydrolysis (4), Colloidal Chemistry (8). The Atmosphere (41, Solubility and Solution (7). Ammonia and Its Compounds (10). Time Reactions (3), Activity of the Elements (6). and Miscellaneous (11). The author has limited himself almost wholly to experiments designed for a relatively small class in general chemistry and, as he announces in the preface, does not attempt to make the list complete. Drawings of set-ups are abundant and well executed. Some of the experiments admit of multiple application to which attention is not called. For enample, Experiment 45, "The Time Reaction of Iodic Acid," could serve also to illustrate the preparation of iodine, the oxidizing power of iodic acid and the effect of temperature an the speed of chemical action. The simplicity of the apparatus and the minuteness of the directions indicate that each experiment must have received careful preliminary testing. Included in the list are original devices as well as
unique modscations of time-honored lecture experiments. Although explanations of the principles involved and references to the original literature are frequently missing, this collection of experiments should he in the hands of every teacher of general chemistry. R. A. BAKER The Hydrous Oxides. HARRYB. WEISER. McGraw-Hill Book Co.. Inc.. New York City, 1926. x 452 pp. 14 X 20 cm. $5.00.
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The literature on hydrous oxide gels and sols is voluminous and has been unavailable in compact form until the appearance of Prof. Weiser's unique book. Following a short but comprehensive review of the theories of gel structure, the properties of precipitates, suspensions,and sols of the following elements are described-iron, chromium, aluminum, gallium, indium, thallium, copper, cobalt, nickel, silver, gold, beryllium, magnesium, zinc, cadmium, mercury, silicon, germanium. tin, lead, titanium, zirconium. thorium, vanadium, columbium, tantalum, antimony, bismuth, molvbdenum, tunasten, uranium, manganese, the rare earths, and the platinum family. There are also chapters on tanning, mordants, water purification, cement, and soil. Dr. Weiser has undertaken a difficult task and has produced a valuable contribution to chemical literature. He has given not merely a "scissors and paste" compilation but has discussed his subject critically. His point of view is that of the mechanistic schwl of colloids. Colloids are shown to he small particles of matter possessing little or no chemical reactivity; they merely adsorb. I t is a pity that the conception of "hydrous oxide" colloids, as pure oxides which adsorb, or are "peptized" by electrolytes or their ions, should he so vigorously defended by the author against such good physico-chemical evidence as composition of the electrophoresced micelles and electrode potential measurements which show
