The text has a unity of organization. So far as practicable the familiar always precedes the unfamiliar in the sequence of topics, and the facts are made to hang together in order that the pupil may see relationships. Such topics as forestry, plant breeding, weeds, plant enemies and diseases, plant culture, decorative plants, and economic bacteria are discussed where most pertinent to the general theme rather than in separate chapters which destroy the continuity. The questions and suggestions which follow the chapters are of two kinds; some are designed merely to serve as an aid in the study of the text, while others suggest outside study and inquiry. The classified tables of terms which precede the index are intended to serve the student in review, and to be a general guide to the relative values of the facts presented. More than 200 attractive illustrations, many of them original, are included in the book.

AMERICAN BOOK COMPANY



A NEW ASTRONOMY, $1.30

By DAVID TODD, M. A., Ph. D., Professor of Astronomy and Navigation and Director of the Observatory, Amherst College.

Astronomy is here presented as preeminently a science of observation. More of thinking than of memorizing is required in its study, and greater emphasis is laid on the physical than on the mathematical aspects of the science. As in physics and chemistry, the fundamental principles are connected with tangible, familiar objects, and the student is shown how he can readily make apparatus to illustrate them. In order to secure the fullest educational value, astronomy is regarded as an inter-related series of philosophic principles.

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MATHEMATICAL GEOGRAPHY, $1.00

By WILLIS E. JOHNSON, Ph. D., Vice-President and Professor of Geography and Social Sciences, Northern Normal and Industrial School, Aberdeen, South Dakota.

This work explains with great clearness and thoroughness that portion of the subject which not only is most difficult to understand, but also underlies and gives meaning to all geographical knowledge. A vast number of facts which are much inquired about, but little known, are taken up and explained. Simple formulas are given so that a student unacquainted with geometry or trigonometry may calculate the heights and distances of objects, the latitude and longitude of a place, the amount any body is lightened by the centrifugal force due to rotation, the deviation of a plumb-line from a true vertical, etc.

AMERICAN BOOK COMPANY



ELEMENTS OF GEOLOGY

By ELIOT BLACKWELDER, Associate Professor of Geology, University of Wisconsin, and HARLAN H. BARROWS, Associate Professor of General Geology and Geography, University of Chicago.

$1.40

An introductory course in geology, complete enough for college classes, yet simple enough for high school pupils. The text is explanatory, seldom merely descriptive, and the student gains a knowledge not only of the salient facts in the history of the earth, but also of the methods by which those facts have been determined. The style is simple and direct. Few technical terms are used. The book is exceedingly teachable.

The volume is divided into two parts, physical geology and historical geology. It differs more or less from its predecessors in the emphasis on different topics and in the arrangement of its material. Factors of minor importance in the development of the earth, such as earthquakes, volcanoes, and geysers, are treated much more briefly than is customary. This has given space for the extended discussion of matters of greater significance. For the first time an adequate discussion of the leading modern conceptions concerning the origin and early development of the earth is presented in an elementary textbook.

The illustrations and maps, which are unusually numerous, really illustrate the text and are referred to definitely in the discussion. They are admirably adapted to serve as the basis for classroom discussion and quizzes, and as such constitute one of the most important features of the book. The questions at the end of the chapters are distinctive in that the answers are in general not to be found in the text. They may, however, be reasoned out by the student, provided he has read the text with understanding.

AMERICAN BOOK COMPANY



ESSENTIALS OF BIOLOGY

By GEORGE WILLIAM HUNTER, A. M., Head of Department of Biology, De Witt Clinton High School, New York City.

$1.25

This new first-year course treats the subject of biology as a whole, and meets the requirements of the leading colleges and associations of science teachers. Instead of discussing plants, animals, and man as separate forms of living organisms, it treats of fife in a comprehensive manner, and particularly in its relations to the progress of humanity. Each main topic is introduced by a problem, which the pupil is to solve by actual laboratory work. The text that follows explains and illustrates the meaning of each problem. The work throughout aims to have a human interest and a practical value, and to provide the simplest and most easily comprehended method of demonstration. At the end of each chapter are lists of references to both elementary and advanced books for collateral reading.

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SHARPE'S LABORATORY MANUAL IN BIOLOGY

$0.75

In this Manual the 56 important problems of Hunter's Essentials of Biology are solved; that is, the principles of biology are developed from the laboratory standpoint. It is a teacher's detailed directions put into print. It states the problems, and then tells what materials and apparatus are necessary and how they are to be used, how to avoid mistakes, and how to get at the facts when they are found. Following each problem and its solution is a full list of references to other books.

AMERICAN BOOK COMPANY



ESSENTIALS OF PHYSICS

By GEORGE A. HOADLEY, C.E., Sc. D., Professor of Physics, Swarthmore College.

$1.25

This is the author's popular and successful Elements of Physics enriched and brought up to date. Despite the many changes and modifications made in this new edition, it retains the qualities which have secured so great a success for the previous book.

It tells only what everyone should know, and it does this in a straightforward, concise, and interesting manner. It takes into consideration the character of high school needs and conditions, and, throughout, lays particular emphasis upon the intimate relation between physics and everyday life.

While the subject matter, as a whole, is unchanged, the order of topics in many cases has been altered to adapt the development of the subject to the habits of thought of high school pupils. Instead of beginning the treatment of a subject with the definition and proceeding to a discussion of the sub-topics, the author starts with a discussion of well-known phenomena and leads up to the definition of the subject discussed. The text, wherever possible, has been simplified, more than fifty topics having been amplified, expanded, or reworded. More familiar illustrations of the topics treated are given, and the demonstrations of many of the experiments are simplified by the use of materials that are readily obtainable in the classroom.

There have been added a number of new topics, mostly in connection with the recent advances in applied science. The number both of questions and problems has been greatly increased and the data in these all relate to actual, practical, physical phenomena. More than one-fifth of the illustrations in the book are new, many of the pictures of apparatus having been redrawn to show modern forms.

AMERICAN BOOK COMPANY

THE END