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NEW BOOKS Surface Active Agents. By C. B. F. YOUNGAND K. W. COONS. Brooklyn, New York: The Chemical Publishing Company, Inc., 1945. Price: WiB.Oo. This book has been criticized as being largely a compilation from trade catalogs and similar sources. However, i t has its definite uses, aa the authors point out, by calling the attention of industrial chemists t o concrete examples of surface phenomena which have been turned to useful account. Many such instances have been developed, such as household recipes or trade or family secrets, where the originators did not know the reasons for the use of the ingredients they utilized. The authors rightly emphasize t h a t reference t o such examples can be stimulating in suggesting ideas about the reader’s own industrial problems. I t is somewhat like the stimulus which any scientist or industrialist receives by v factory in some unrelated industry, which nevertheless suggests ideas which he can develop in his own field. The book cannot be taken as a piece of careful scientific writing. For example, on page 4, under the heading “Definitions”, the definition of surface-active agents, the subject of the book itself, is “Compounds which cause variations in either interfacial tension or surface tension.” The authors do not mean this as a scientific statement. It is either meaningless or untrue. The authors had just before pointed out t h a t sodium chloride is not a surface-active agent, although it does raise the surface tension of water. Practically all dissolved substances and many insoluble substances cause variations, either plus or minus, in the surface tension of water; and therefore all are included i n the “definition”, although this is by no means the intention of the authors. Again, on the same page, the authors state that the forces between molecules are equal in all directions, whereas the most significant feature of surface phenomena is the orientation of molecules caused by the unequal distribution of molecular forces around the different parts of the same molecule. On the following page, “work” is expressed in “dynes per centimeter . I ’ Incorrect or misleading statements such as those just cited are not uncommon in scientific writing, and lend support to the allegation that scientists as a rule are uneducated men. The fault must lie in the system of education in the science departments of our universities. For the convenience of instructors, too much reliance is placed upon the true or false system of examinations. The more intelligent pupils realize t h a t they are being forced t o give answers that are not strictly true but have to be fitted into the Procrustean framework provided by the busy examiner. It is seldom that a pupil is required to produce a piece of rigorous scientific writing in which each statement is true to the best of his knowledge and power of expression. However, this is no valid reason why professors or trained industrial chemists or scientistsin generalshould be careless of the truth. Kevertheless the vitality of the scientific method and the permanence of demonstrable fact are such that man’s material achievements have been accomplished in spite of halftruths and imperfect theory. The purest scientist has to reflect t h a t much of current theory which he is teaching, viewed in the light of previous history, will prove to be imperfect or erroneous and only the stubborn scientific facts will endure. However, this is no reason for publishing statements that are obviously untrue or misleading or not expressed t o the best of one’s ability. The book brings together a lot of information of proven utility. It begins with a chapter on the “Theory of Surface Tension”, already commented upon. Next is a detailed account of “Determination of Surface Tension”, and much of the illustrativematerial is taken from the authors’ own work. The reader will be dismayed and bewildered by figures 6 and 7, which indicate t h a t none of the methods of determining the surface tension of water give the value recorded in the International Critical Tables or Landolt-Bdrpstein but t h a t , depending upon the six methods given, the surface tension of water varies between 68.9 and 91.3. Furthermore, when the dissolved substance is added, in figure 7, some of the methods
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show a rapid diminution of surface tension, others a n increase above that of water. . What is truth? The remaihder of Part I is frankly mainly a condensation from a well-known symposium, but includes a convenient listing of commercial wetting agents and detergents. Part.JX .has a chapter each on “Emulsions”; “Plating, hfetal Cleaning, Pickling and Etching”; “Cosmetios’: j“Leather”; “Flotation”; “Inks”; “-4pplication of Surface Tension t o Textiles”; ‘!Cutting and Soluble Oils”; “Adhesives”; “Foods”; “Lubrication”; and “Soldering, Brasing.and Welding”-all with illustrative formulae and a modicum of theory. This constitutes the.brief compendium of practical information taken from these various fields. hluch of it remain8.a challenge to the scientist. J. W. MCBAIN.
Fundamentals of Physics. By HENRYSEMAT. 593 pp. New York: Farrar and Rinehart, 1946. Price: $4.00. I n the preface the author indicates that this text is intended as a first-year college physics text for students having different degrees of preparation. The most advanced mathematics employed is trigonometry and this very sparingly. Each of the thirty-two chapters includes a set of questions and a set of problems. The questions should be useful t o the student in his studying and in many cases will be valuable for stimulating class discussions. The problems are fairly simple, generally involving the application of only a single principle. Answers are given to all odd-numbered problems; answers to the remaining problems can be obtained. The text contains a liberal number of carefully worked illustrative examples. Both the metric and English systems of units are employed. To avoid confusion in the discussion of mass, weight, and subsequent topics in mechanics, the only units of force mentioned are the dyne and pound; gram force and poundal are avoided entirely. The entire discussion of Newton’s laws and the definition of mass and force are clearer than those found in most elementary texts. I n the section on electricity and magnetism, the electrostatic, electromagnetic, and practical systems of units are employed in their appropriate places. Some of the more fundamental derivations of elementary physics are omitted. For example, the relation between period, displacement, and acceleration for a simple harmonic motion is not discussed. The formula for the period of a simple harmonic motion is stated but not derived. I n the section on rotational motion extensive use is made of the formula relating to torque, moment of inertia, and angular acceleration of a rigid body free to rotate about a fixed axis without attempting to derive i t . The same statement may be made about the use of the theorem for computing the moment of inertia about an axis parallel t o one through the center of maas. Xo attempt is made to derive the relation between focal length and object and image distance for a lens or spherical mirror, although considerable use is made of the equation. Again, in the section on electricity a whole chapter is devoted to alternating current circuits, including series circuits containing resistance inductance and capacitance. The circuits are solved by the familiar vector diagram method. However, nowhere in the text is mention made of the generation of a sinusoidal curve by a rotating vector. The expression for conductive reactance is used without explanation of its origin. I n spite of some of these shortcomings, the book should be very useful as a beginning text. Presentation of material is in a straightforward and logical manner. Explanations are generally clear and concise. Because of the rather elementary approach to most topics its level is too low for use by engineering students, unless the course were followed by one employing a more mathematical treatment. A few errors are t o be found. On page 125 a slip has been made in writing the last equation. In several places on page 359 inductive reactance is written in place of capacitive reactance. ALFRED0. NIER.
