This volume is intended for persons who have not had special training in the technicalities of climatology. Climate covers a wholly different field from that included in the meteorological text-books It handles broad questions of climate in a way which has not been attempted in a single volume The needs of the teacher and student have been kept constantly in mind.

20.—Heredity. By J. Arthur Thomson, M.A., Professor of Natural History in the University of Aberdeen; Author of "The Science of Life," etc. 8°. Illustrated. Net, $3.50.

The aim of this work is to expound, in a simple manner, the facts of heredity and inheritance as at present known, the general conclusions which have been securely established, and the more important theories which have been formulated.

21.—Age, Growth, and Death. By Charles S. Minot, James Stillman Professor of Comparative Anatomy in Harvard University, President of the Boston Society of Natural History, and Author of "Human Embryology," "A Laboratory Text-book of Embryology," etc. 8°. Illustrated.

This volume deals with some of the fundamental problems of biology, and presents series of views (the results of nearly thirty years of study), which the author has correlated for the first time in systematic form.

22.—The Interpretation of Nature. By C. Lloyd Morgan, LL.D., F.R.S. Crown 8vo. Net, $1.25.

Dr Morgan seeks to prove that a belief in purpose as the causal reality of which nature is an expression is not inconsistent with a full and whole-hearted acceptance of the explanations of naturalism.

23.—Mosquito Life. The Habits and Life Cycles of the Known Mosquitoes of the United States; Methods for their Control; and Keys for Easy Identification of the Species in their Various Stages. An account based on the investigation of the late James William Dupree, Surgeon-General of Louisiana, and upon the original observations by the Writer. By Evelyn Groesbeeck Mitchell, A.B., M.S. With 64 Illustrations. Crown 8vo. Net, $2.00.

This volume has been designed to meet the demand of the constantly increasing number of students for a work presenting in compact form the essential facts so far made known by scientific investigation in regard to the different phases of this, as is now conceded, important and highly interesting subject. While aiming to keep within reasonable bounds, that it may be used for work in the field and in the laboratory, no portion of the work has been slighted, or fundamental information omitted, in the endeavor to carry this plan into effect.

24.—Thinking, Feeling, Doing. An Introduction to Mental Science. By E. W. Scripture, Ph.D., M.D., Assistant Neurologist Columbia University, formerly Director of the Psychological Laboratory at Yale University. 189 Illustrations. 2d Edition, Revised and Enlarged. Crown 8vo. Net, $1.75.