dant applications of physical chemistry t o physiological processes. The reader is strongly impressed with the army cited, and feels that the author has proved his claim that i t is "imperative for the student of medicine to acquire some knowledge of that branch (i.r , physical) of ehemiotry." The style of the book is good, the subject matter is well orpadzed, and the treatment is clear and logicel. Perhaps a more or Less excusable lapse is the use of the old theory of primary electrolysis to explain the electrolytic decomposition of sodium sulfate solution (page 69). The book will be cordially received by physiologists and medical men who desire s eonvenient and clear discussion of physieo-physiologicalehemistry. J. H. Rgsov Chemistry for Boys and Girls. C ~ a ~ o r C. m G a a m &ND I. CORA B H N N H ~AIIym . and Baeon. 1025. $1.80. Psrges III-XVII; 1-776; 1-68. 12.7 X 18.4cm. Figures, 159. This volume is a chemistry for pupils in high schools. I t is unique in several respects. I t is readable even by the pupils for whom it is intended. I t not only- recognizes the language limitations of senior high-8ehool boys and girls hut shows an appreciation of their intere~tsasmell. An early chapter has the caption "Metals and Their Rusts." This is one of several instances in which it breaks with the traditional order of development. Formal use of formulas and equations is not undertaken until the pupil has had a semester's experience in the subject. Formulas and equations are, to most high-school students, a new and often a rather mysterious way of expresringchemieal howledge. This text permits the pupil to gain some of this knowledge before requiring such symbolic expression. The laboratory experiments are ihco-ated with the material of the text. Authors, here-tof a e , have not been successful in this method of eoardinating laboratory and class work. T w aften the discvrsion before end after the experiment has taken all the pith out of the problem. I n the b w k vnder review, the experiments have been selected with such care and the requirements so worded that this objection has been, in a large measure, met. The superior student'. needs are cared for by extra erperiments of a more abotraet and quantitative eharncter placed in an appendix. The chapter treatment is inductive starting from pupil experiences and pupil performed experiments. The l o g i d relationships of concepts and principles a r e emphasized by a logical summary a t the close of eaeh chapter. Further applications and enrichment of the subject is encouraged by especially well selected exercises a t the close of each chapter. The book could be improved by keaking up the present content into shorter chapters. The treatment of oxidation and redvetion is rnther out of date. The appendix l i d of experiments
does not include much help for the first half of the year's work. The binding is going to he sorely tried by the eight hundred pages of a book intended for the double use of clasrstudy and laboratory. B. C ~ ~ a s o aHENDRICXS o
A Test of Hiph-School
Chemistry. HENRY G E ~ Y .Harvard Universitv. Bulbtins of Education, Graduate School of Harvard University, No. IX. Published by Harvard University, 1924. 82 pp. LBsTBR
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This monograph describes the method used by the author in the selection of the items for his teat of h i p h - ~ h m lchemistry and the methods used in its evaluation and standardization. The first baain for selection of the original test items was an analysis of all the College Entrance Examination Board questions in chemistry used from 1911 to 1920. About 70 questions were obtained from this source. I n order t o extend the range of diffieulty the number was supple. mented by questions from other sour- some of which were very easy and some very difficult. To assure certainty that the questions concerned topics that are usually taught and that the most important topics of the course were represented in the test each quertion was checked by four textbooks. Two types of questions were used: multiple choice and completion. The preliminary tent wna arranged in two forms. Form A consisted of 49 items and Form B of 47 items. Each form was administered. near the dose of the schoolyearof1Q2+21tomorethan600students who had studied chemistry throughout the year under fairly uniform conditions. A median score of 13 of the nearly 50 items of eaeh form, and the fact that more than 20 items of each form were answered eorreetly by 15 per cent or less of the experimental group indicated that the preliminary forms contained an over rvpply of difficult tasks. Questions for the final forms were selected from those usedin the preliminary forms. some questions were eliminated that were apparently unsuited to the purpose of a standardizqi examination on account of diffieulty. A statirtieal device was "zed t o oeleet from those of equivalent difficulty those best suited for testing purposes. Sucees=es with questiono of equivalent difficulty were compared with successes with easier ones. If the pupils answering one question of given difficulty show a larger percentage of sueee~seswith a11 easier items than th0.e answering another item of the same difficulty then the former i n rated as mare satisfactory. Selection was made on the basis of comparative success with easier questions a t intervals of 0.5 P. E. The Bnal test contained 25 questions in each lorn. The standard score on Form A was derived from the scorer of 1545 students: for Form B from 1339 students. Oo Form Atwostudents made zero scores and none made a perfect score; on Form B one student made zero score and none made a perfect score. The range of difficulty
of each form is, therefore, sufficiently wide. The median on Form A after a "ear of instruction is 10.6; sigma 4.1. The median for Farm B is 11.6; sigma 4.4. For the half year t h e medians (from a smaller nvmher of eases) are 8.5 and 7.4. The correlation between scores on Form A and Form B is 0.78 f 0.008. The probable error of estimate of Form A i. 1.8 and of Form B is 1.9. Almost exactly t h e same amount of time was iouod t o be required for the administration of each form. The median time requirement for Form A is 32.5 minutes, sigma 11.5. This means that approximately 8 5 per cent of the erperimental group were able t o complete the test in 44 minute.. Test scores made by pupils in a few schools were compared with teachers' marks for these same pupils and with marks which they obtained from t h e College Entrance Examination Board. The correlation factors show t h a t the test r e d i s agree with t h e criteria as well as the criteria agree ~
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The d a t a show t h a t "(1) between themrelve.. in 50 per eent of t h e cares the tests determine i n 90 minuter (using both forms) a reore within four paints, on a percentile scale. of what t h e teacher had a~signedafter nine months of acquaintance: (2) in 50 per eent of the cares, t h e College Entrance Examination Board's marks estimated from t h e sum of t h e scores on Forms A and B were within 7.6 paints of the College Board marks actually received: and (3) in 50 per eent of the cares, t h e College Board marks, estimated from t h e teachers' marks were within 7.7 points of t h e College Board marke received. These d a t a indicate t h a t the test results were a better prediction of College Board marks than were the teachers' estimates." The monograph reports t h e results of a careful piece of wort. The avfhor mares a strong case for the use of tests like his for supplementary measure. of t h e resulte of instruction in highs. R. ~ o m t a s school chemistry.
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