DARWIN.—THE ORIGIN OF SPECIES by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life. New and revised edition, with Additions. With Copious Index. 1 vol., 12mo. Cloth. Price, $2.00.

——THE DESCENT OF MAN, and Selection in Relation to Sex, With many Illustrations. 2 vols., 12mo. Cloth. Price, $4.00.

This work, in which the author expresses his peculiar views boldly and forcibly, has been widely read and criticised, and, whatever may be the opinion arrived at in regard to his theories, the reader cannot fail to obtain pleasure and profit in its perusal.

——JOURNAL OF RESEARCHES into the Natural History and Geology of the Countries visited during the Voyage of H. M. S. Beagle round the World. A new edition, uniform with "Origin of Species" and "Descent of Man". 1 vol., 12mo. Cloth. Price, $2.00.

An interesting account of a voyage of scientific research and discovery.

HUXLEY.—MAN'S PLACE IN NATURE. 1 vol., 12mo. Cloth. Price, $1.25.

——ON THE ORIGIN OF SPECIES. 1 vol., 12mo. Cloth. Price, $1.00.

——LAY SERMONS, Addresses, and Reviews. 1 vol., 12mo. Cloth. Price, $1.75.

——ELEMENTS OF PHYSIOLOGY, and Hygiene. By T. H. Huxley and W. J. Youmans. 1 vol., 12mo. $1.75.

——MORE CRITICISMS ON DARWIN, and Administrative Nihilism. 1 vol., 12mo. Price, 50 cents.

Valuable to all who are interested in scientific study or reading.

PROCTOR (R. A.)—OTHER WORLDS THAN OURS: the Plurality of Worlds, Studied under the Light of Recent Scientific Researches. By Richard A. Proctor, B. A., F. R. A. S., author of "Saturn and its System," "Sun Views of the Earth," "Half Hours with the Telescope," etc. With Illustrations, some colored. 12mo. Cloth. Price, 2.50.

PROCTOR (R. A.)—LIGHT SCIENCE FOR LEISURE HOURS. A Series of Familiar Essays on Scientific Subjects, Natural Phenomena, etc. 1 vol., 12 mo. Cloth. Price, $1.75.

An instructive and entertaining volume to the student of science, and of astronomy.

SPENCER (HERBERT)—EDUCATION, Intellectual, Moral, and Physical. 12mo. Cloth. Price, $1.25.

——FIRST PRINCIPLES. 12mo. Cloth. Price, $2.50.

——CLASSIFICATION OF THE SCIENCES. 8vo. Paper. Price, 25 cts.

——ESSAYS: Moral, Political, and Æsthetic. 1 vol., 12mo. Cloth. Price, $2.50.

——ILLUSTRATIONS OF UNIVERSAL PROGRESS. A Selection of his best Papers. 1 vol., 12mo. Cloth. Price, $2.50.

——SOCIAL STATICS; or, the Conditions Essential to Human Happiness Specified, and the First of them Developed. 1 vol., 12mo. Cloth. Price, $2.50.

——THE PRINCIPLES OF BIOLOGY, 2 vols., 12mo. Cloth. Price, $5.00.

——THE PRINCIPLES OF PSYCHOLOGY: Part I. Data of Psychology. 1 vol. Paper. Price, 75 cents; Part II. The Inductions of Psychology. 1 vol., 8vo. Paper. Price, 75 cents; Part III. General Synthesis; Part IV. Special Synthesis. Paper. Price, $1.00; Part V. Physical Synthesis. Paper. Price, 75 cents.

——THE PRINCIPLES OF PSYCHOLOGY. Vol. I., 8vo. Cloth. Price, $2.50.

——WORKS. 7 vols., Svo. Half Calf. Price, $28.00.

The works of Herbert Spencer have attained a prominence and a reputation in America even greater than in England, and he stands the acknowledged leader of a school of philosophy which counts many students and thinkers among his followers.