BOOK REVIEWS Protective and Decorative Coatings. Joseph J . Mattiello, Editor. 1’01. V. Analysis and Testing Methods. 662 pages. John Wiley & Sons, Inc., 440 Fourth Ave., New York 16, N. Y., 1946. Price, $7. I n the fifth and latest volume of his series, Dr. Mattiello continues his campaign t o place t h e field of protective and decorative coatings on a firm scientific basis of its own. I n answer t o the need for systematizing analytical techniques necessitated by the ever-widening variety of new resins and their modifications, he has enlisted the services of several competent author-scientists to contribute t o this work. As with so many other fields of chemical endeavor t h a t have experienced constantly accelerated growth, this industry has amassed data and know-how faster t h a n it could organize and appraise them. Tests t h a t once served as criteria for a given application of a product no longer sufficed to indicate its suitability for a new employment, and so the control chemist gradually lost contact with the firing line of end use. T h e avalanche of new raw materials and unique applications brought about by the war made i t mandatory t h a t the control and research laboratories of the efficient finish company function in close liaison with the actual need. I n order to do this, it was necessary t o approach the problem from a practical yet academic viewpoint, which is the basic theme of this book. T h e first chapter, by R . W.Stafford and E. F. TT’illiams, presents a classification of resins, and means of isolating and studying them by qualitative, physicochemical, and certain special methods. The classification breakdown is: natural resins and their modifications, alkyd resins, aldehyde condensation products, vinyl resins, rubber and rubberlike synthetics, hydrocarbon, and inorganic resins. I n addition, the natural and synthetic waxes, carbohydrate, and protein materials are included. A brief discussion of t h e chemical properties and structure of each member of the above families is given in so far as i t bears on their determinations. The second portion of the chapter deals with the analysis of these materials by routine methods and closes with interesting discussion of x-ray radiographic and x-ray diffraction methods of analysis. Chapter I1 is concerned with methods for testing and analyzing drying oils. The authors, T. F. Bradley and E. L. Kropa, point out t h a t very few industrial laboratories are concerned with the quantitative determination of a pure fatty acid or its glyceride but rather with the technological values and effectiveness of the material. Viscosity measurements, molecular weight determination, and means for determining the type and degree of unsaturation are discussed, and considerable space is devoted to the use of the thiocyanogen value. The chapter closes with valuable tables of the physical and chemical constants of the commercial fat acids. A critical appraisal is made in the third chapter of the methods of laboratory testing of metal finishes for outdoor service. The author, S. E. Beck, discusses standardized panel preparation, humidity testing, and the effects of light, temperature, and air circulation on the drying of t h e films. The sections on statistical evaluation and color are particularly interesting, as are the discussions of abrasion, bending, and flexibility testing. The spectral characteristics of pigments in the visual and infrared bands are dealt with by V. C . Vesce in three parts: (1) photographic method of measuring visual ‘and infrared reflectances of pigments and pigmented coatings, ( 2 ) a spectrophotometric method for the determination of reflectances for the four wave-length bands by the selected ordinate method, and (3) spectral characteristics of pigments. This latter section presents a series of spectrophotometric curves on a large number of synthetic and natural pigments. The chapter on “Resinography”, by T. G. Rochow and R. L. Gilbert, introduces a new approach t o resin study t h a t in purpose is related t o the analogous fields of metallography and mineralography. Because of the heterogeneous nature of most molded resins it has become useful t o study the mode of association of the filler with the embracing resin. I n addition, the “metallographic approach” will identify the filler, if it be a metal, and furnish valuable information
on the history of fabrication as well. Should the filler be of a mineral nature, either natural or synthetic, a mineralographic approach will yield similar desirable data, Resinography is also concerned with the structure of the resin or resins involved by studying the resinous phases t h a t may be present and their relationships by difference in refractive index, reflectivity, color, hardness, the effect of polarized light, etc. Indirect methods employing selective staining, selective dissolution, and differential etch patterns are valuable in this respect. The chapter also includes sections on the use of instruments such as the optical microscope and camera and electron microscope in examination of resin specimens. This book seems to serve well as a clearinghouse and sifting medium for the many diversified but often confusing methods of analysis t h a t have arisen in this field. RICHARDL. DEMMERLE
Spectrographic Analysis of Metallurgical Products The Groupement pour l’hvancement des MBthodes d’Analyse Spectrograyhique des Produits MBtallurgiques has published as a 92-page book the proceedings of its fifth congress, which was held January 22 to 24, 1946. I n addition to a report of the meeting and a list of members present, the book includes four technical papers, with discussion: Le Dosage Spectrographique des Faibles Teneurs en Aluminium dans les Aciers Ordinaires e t SpBciaux, by R . Castro; Causerie sur les Spectrographes, by H. Tardy; Luminositb Comparhe d u Spectrographe Zeiss Qu 24 et du Spectrographe ZBlande de Jobin et Yvon, by E. Loeuille; and Le Dosage des Traces d’Impureths dans les Alliages de Zinc au Moyen de 1’Etincelle Condensbe, by P. Croissant. Copies are available through the Centre de Documentation Siderurique, 12 Rue de Madrid, Paris 8, France.
Apparatus for Small-Scale Catalytic Hydrogenat ion-Correspon
dence
SIR: T h e continued interest in the apparatus for small-wale catalytic hydrogenation [IsD. ENG. CHEM., ANAL. ED., 14, 907 (1942)], as evidenced by requests for reprints, makes it desirable to describe a modification of the apparatus made shortly after t h e original article was published. Instead of having the cup and stopcock on the reaction flask, where it caused instability and led to frequent breakage, i t was incorporated in the main portion of the apparatus, as indicated in the accompanying diagram. This modification permits the use of any Erlenmeyer flask having an interchangeable ground-glass joint as the reaction vessel. C. R . NOLLER STANFORD CMVERSITY, CALIF.
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