HOURS OF EXERCISE IN THE ALPS. With Illustrations. 12mo. Cloth, $2.00. FARADAY AS A DISCOVERER. A Memoir. 12mo. Cloth, $1.00. CONTRIBUTIONS TO MOLECULAR PHYSICS in the Domain of Radiant Heat. $5.00. SIX LECTURES ON LIGHT. Delivered In America in 1872-'73. With an Appendix and numerous Illustrations. Cloth, $1.50. ADDRESS delivered before the British Association, assembled at Belfast. Revised with Additions. 12mo. Paper, 50 cents. RESEARCHES ON DIAMAGNETISM AND MAGNECRYSTALLIC ACTION, including the Question of Diamagnetic Polarity. With Ten Plates. 12mo, cloth. Price, $1.50. CHARLES DARWIN'S WORKS. ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION, OR THE PRESERVATION OF FAVORED RACES IN THE STRUGGLE FOR LIFE. From sixth and last London edition. 2 vols., 12mo. Cloth, $4.00. DESCENT OF MAN, AND SELECTION IN RELATION TO SEX. With many Illustrations. A new edition. 12mo. Cloth, $3.00. JOURNAL OF RESEARCHES INTO THE NATURAL HISTORY AND GEOLOGY OF COUNTRIES VISITED DURING THE VOYAGE OF H.M.S. BEAGLE ROUND THE WORLD. New edition. 12mo. Cloth, $2.00. EMOTIONAL EXPRESSIONS OF MAN AND THE LOWER ANIMALS. 12mo. Cloth, $3.50. THE VARIATIONS OF ANIMALS AND PLANTS UNDER DOMESTICATION. With a Preface, by Professor ASA GRAY. 2 vols. Illustrated. Cloth, $5.00. INSECTIVOROUS PLANTS. 12mo. Cloth, $2.00. MOVEMENTS AND HABITS OF CLIMBING PLANTS. With Illustrations. 12mo. Cloth, $1.25. THE VARIOUS CONTRIVANCES BY WHICH ORCHIDS ARE FERTILIZED BY INSECTS. Revised edition, with Illustrations. 12mo. Cloth, $1.75. THE EFFECTS OF CROSS AND SELF FERTILIZATION IN THE VEGETABLE KINGDOM. 12mo. Cloth, $2.00. DIFFERENT FORMS OF FLOWERS ON PLANTS OF THE SAME SPECIES. With Illustrations. 12mo. Cloth, $1.50. THE POWER OF MOVEMENT IN PLANTS. By CHARLES DARWIN, LL.D., F.R.S., assisted by FRANCIS DARWIN. With Illustrations. 12mo. Cloth, $2.00. THE FORMATION OF VEGETABLE MOULD THROUGH THE ACTION OF WORMS. With Observations on their Habits. With Illustrations. 12mo. Cloth, $1.50. ALEXANDER BAIN'S WORKS. THE SENSES AND THE INTELLECT. By ALEXANDER BAIN. LL.D., Professor of Logic in the University of Aberdeen. 8vo. Cloth, $5.00. The object of this treatise is to give a full and systematic account of two principal divisions of the science of mind--the senses and the intellect. The value of the third edition of the work is greatly enhanced by an account of the psychology of Aristotle, which has been contributed by Mr. Grote. THE EMOTIONS AND THE WILL. By ALEXANDER BAIN, LL.D. 8vo. Cloth, $5.00. The present publication la a sequel to the former one on "The Senses and the Intellect," and completes a systematic exposition of the human mind.