RECENT BOOKS MODERNCHBMI~TRY. Charles E. DuZZ, Head of Science Department, West Side High School and Supervisor of Science for the Junior and Senior High Schools, Newark, New Jersey. Fourth edition. Henry Holt & Co., New York City. 1936. xliii f 745 pp. 390 figs. 12.5 X 18.5 cm. $1.80. This well-known textbook of high-school chemistry, whose third edition appeared in 1931, was first published in 1918. The author claims far the scope of the book: (a) an introduction to the study of chemistry, not alone for specialization,but for its cultural value; (b) a practical study in which fundamental principles are not neglected; ( 6 ) the development of the chemical theory in a clear, concise, and logical manner; (d) the presentation of material needed to meet college entrance requirements. The book is arranged in forty-two chapters which may be classified as fdows: Part I, introduction and chemical theory. chapters 1-13 (205 pp.); Part 11, study of non-metals, ionization and the periodic classification of elements, chapters 14-29 (285 pp.); Part 111, the metals, chapters 3 W 0 (188 pp.); Part IV, carbon compounds. chapters 41 and 42 (67 pp.). At the beginning of each chapter a short vocabulary of the unfamiliar words is given to aid the student and a t the end a summary of the important facts and principles developed in the chapter. The questions and problems which follow the s m mary are divided into two classes: "Those given in the AGroups are not difficult for any pupil. The questions and problems given in the B-groups may be assigned as an extra group for
the more capable pupil or for those who work more rapidly." I n some instances, references are given as supplementary projects. At the end various useful tables are appended. The plan of the arrangement and presentation of the material follows to a large extent the traditional method. The chemical theory is developed mainly through the study of oxygen. hydrogen, and water. Acids, bases, and salts are introduced before ionization, which is taken up after the study of nitrogen and its compounds, and carbon and its compounds, as late as page 343, a procedure which is of dubious value. The periodic table is not introduced until after the study of sulfur and its compounds and the halogens. Then follows the study of the metals and the organic compounds. There is a good attempt to introduce modem views and theories. The achievement, however, falls short of the aim, because no use is made of principles in explaining the large amount of factual material which the hook contains. The electron theory of matter is b r i d y given a t the very beginning (pp. 28-30) but no use is made of this concept in explaining oxidation and reduction (pp. 47, 75, 264-270, 350, 359, etc.), the activity series. etc. Again, the student, a t the beginning is informed (p. 73) " 'heavy hydrogen'-in its chemical behavior-& much like ordinary hydrogen, but it is twice as heavy. I t combines with oxygen to form 'heavy water.' " The statement is meaninglw unless the matter of isotope is explained, even in a somewhat rudimentary fashion. When isotopes are explained (pp. 436-7) chlorine is used as an example and the opportunity again is
missed to point out that isotopes differing as much as 100 per cent. do show differences in the compounds they form, because already under water, the facts of differences in density, freezing point, toxicity, etc., were given (p. 105). The same thing is true with reference t o compounds formed by sharing electrons. No use of the concept is made. Again, a t the end of the chapter on ionization the structure of crystals as revealed by X-ray analysis is treated. There has been in the previous pages (pp. 181-189). a rather good discussion of the electron theory of valence. The sodium chloride on page 347 is represented as molecules which d i m i a t e into ions, "-The sodium atom loses an electron (Na - e = Na+)and becomes positively charged. The chlorine atom gains an electron (C1 e = CI-) and thus acquires a negative c h a r g e . " At the end of the chapter, under the topic of the structure of crystals, sodium chloride is pictured as "built up of ions held together by electrical attraction" and after showing a picture of the crystal lattice, the brief discussion is ended with the statement that "when snch a crystal is melted-the ions which are loosened from their electrical attraction become free to migrate." This last topic is starred, denoting that it can be omitted without affecting the unity of the course. Now, if i t was thought advisable to include this factual material, it should have been connected with the ionization of these molecules "made up of ions." The treatment of the metals is well done. The discussion of organic compounds is subject t o the same criticism as in practically all other high-school texts, namely, that no attempt is made t o project the material into a background with which the student is already familiar, so that we deal with a vast accumulation of facts with no correlating principles. The pictures and diagrams are numerous and well selected. Some of the diagrams need better explanations (pp. 255. 304. 314, 679). The number of errors that have crept in is not excessive. On page 29 the theory of the "planetary" atom is ascribed t o Bohr. On page 284, third line from the bottom. the word diamond should read diameter. All things considered, it is the opinion of the reviewer that the text represents a good work for the beginner in high school. However, the author does not M y attain his aim to "make this book practical without neglecting the fundamental principles." There is entirely t w much factual material left "loose and hanging in the air." I n addition to the examples pointed out, two of the many can be cited. On page 511, among the uses of sodium, i t is stated that "as a catalyst, i t converts isoprene, CaHs,into artificial rubber." It is difficult to imagine the benefit of the statement that artificial rubber results from "the catalytic action of sodium on CrH8" to a student who thus far knows nothing of organic compounds. Finally, the last entry in Appendix B which closes the hook, reads, "What is meant by the pH value?" The explanation which follows is neither clear nor adequate. If it was desirable t o include a word on pH, i t would have been better t o merely give pH as an arbitrary scale of relative acidity and alkalinity, for example, p H 1-2 as a strong acid, pH 3-4 as a weak acid, p H 7 as neutral, pH 9-10 as weakly alkaline, and pH 12-13 as strongly alkaline, etc. The overabundance of ill-connected factual material, although i t may be practical, usually does not lead to a well-organized exposition of beginning science. This limitation is commonly offset by the instmctor. The work of the publishers is very good. The hook is printed on good paper, is attractively bound and easy t o read.
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C~ICIOO CITYCOLLBD&S C~EADO ILLINOIS .
NICHOLAS D. CHKRONlS VALUESOF TEE BANANA-A DIN u r r u r m AND THERAPEUTIC GEST oa SCIENTIFIC L~TERATUEE.Published by the Research Department, United Fruit Company. Boston, Massachusetts, 1936. 143 pp. 17.5 X 25 cm. Paper-hound. Subject index; 292 references. This pamphlet contains a digest of scientific literature on the subject.
BRITISH CHEMICALS AND THEIR MANURACTURERS: THE OPFICIAL DIRECTORY oa THE ASSOCIATION OR BRITISACHEMICAL MAN~~ACTURERS. Association of British Chemical Manu- ~ f a c t u r e ~ 166 ~ , Piccadilly, London, W. 1, England, 1937. 466 P P 13.5 X 21.5 cm. This book is obtainable gratis by enquirers who are genuine purchasers of chemicals. Copies are only issued from the office of the Association to snch enquirers. OFFICIA~.AND TENTATIVE METHODSOF ANALYSIS OF THE ASSOCIATION OF OFPICUL AGRICULTURAL CHEMISTS. W. W. Skinner, Chairman of the Editorial Board. Fourth edition. enlarged and revised. Assaciation of Official Agricultural Chemists, Washington, D. C.. 1935. xviii 710pp. 15 X 23 cm. $5.00 Domestic, $5.50 Foreign.
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"The fourth issue of Oficial and Tenlativc Methods of Annlysis of the Association of Oficial Agricultural Chmnists ('Methods of Analysis' or 'Book of Methods') is presented in accordance with the plan to publish a revision every five years. This book continues to " mow in size and in the diversitv of its suhiect matter -~~~ ~~~-in ~~harmony with the widening horizon of official chemists, who campose the Association. The philosophy of the Association, however, remains the same as in the beginning. "The general arrangement of subject matter follows the plan adopted for the second and third editions. Certain unsatisfactory methods have been omitted, for instance, the method for the determination of fluorine in baking powders. No general method for this determination has been included, since no satisfactory method has been perfected, although specific procedures for its determination under insecticides and waters have been presented as tentative methods. This subject is being intensively studied by the members of the Association and others, and those interested should refer t o 'The Journal' of the Assoriatian for the latest developments. The methods for beers, wines, and distilled liquors, which constitute Chapter XVII in the third edition, have been assembled in three chapters entitled, respectively, Malt Beverages, Sirups and Extracts, and Brewing Materials; Wines; and Distilled Liquors. Two chapters of the third edition, i. e.. XI1 Fibers, and XIV Paper and Paper Materials, have been deleted because a t the present time the work on these materials is not considered to be of sufficient importance t o enough members of our Association to warrant cobperative referee work, and further because such methods are being satisfactorily studied elsewhere. "Attention is called t o a few of the additions t o the methods which have special significance. I n Chapter I, Soils, the method for the determination of selenium is timely, as is also the method for the determination of the acid-forming and non-acid-forming quality of fertilizers, in Chapter 11, Fertilizers, because these subjects have assumed special importance during the last two years. The methods for the determination of the phenol coefficient of disinfectants, included in Chapter VI on Insecticides and Fungicides, is an example of a departure into a field of more unusual methods. Chapter XII, Plant, has been materially revised and enlarged, and now includes a method for the determination of lignin. Methods have also been added under the chapter heading 'Nuts and Nut Products.' "The method for the determination of lead given in the chapter on Baking Powders has been deleted. Only the comprehensive method for lead in Chapter XXIX, Metals in Foods, has been included. The vitamin D assay by preventive biological test in Chapter XXVII, Grain and Stack Feeds, should be noted, as should also the revised and rearranged Chapter XXXIV. Sugars and Sugar Products. "Another innovation which should later make a valuable addition t o the hook is Appendix I, which presents methods for the preparation and standardization of solutions. At present only procedures for hydrochloric acid and alkali are given, hut with the appointment of a referee on this subject other material will soon be available. A revised and enlarged section an definitions of terms and interpretation of results on fertilizers and liming materials constitutes Appendix 11." ~s
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