e 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.

* * * * *

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 ELI