Chapter I: Front Matter

THE INTERNATIONAL SCIENTIFIC SERIES.

VOLUME VII.

THE INTERNATIONAL SCIENTIFIC SERIES.

_Works already Published._

I. FORMS OF WATER, IN CLOUDS, RAIN, RIVERS, ICE, AND GLACIERS. By Prof. JOHN TYNDALL, LL. D., F. R. S. 1 vol. Cloth. Price, $1.50.

II. PHYSICS AND POLITICS; OR, THOUGHTS ON THE APPLICATION OF THE PRINCIPLES OF “NATURAL SELECTION” AND “INHERITANCE” TO POLITICAL SOCIETY. By WALTER BAGEHOT, Esq., author of “The English Constitution.” 1 vol. Cloth. Price, $1.50.

III. FOODS. By EDWARD SMITH, M. D., LL. B., F. R. S. 1 vol. Cloth. Price, $1.75.

IV. MIND AND BODY: THE THEORIES OF THEIR RELATIONS. By ALEX. BAIN, LL. D., Professor of Logic in the University of Aberdeen, 1 vol., 12mo. Cloth. Price, $1.50.

V. THE STUDY OF SOCIOLOGY. By HERBERT SPENCER. Price, $1.50.

VI. THE NEW CHEMISTRY. By Prof. JOSIAH P. COOKE, Jr., of Harvard University. 1 vol., 12mo. Cloth. Price, $2.00.

VII. THE CONSERVATION OF ENERGY. By Prof. BALFOUR STEWART, LL. D., F. R. S. 1 vol., 12mo. Cloth. Price, $1.50.

VIII. ANIMAL LOCOMOTION; OR, WALKING, SWIMMING, AND FLYING, WITH A DISSERTATION ON AËRONAUTICS. By J. BELL PETTIGREW, M. D., F. R. S. E., F. R. C. P. E. 1 vol., 12mo. Fully illustrated. Price, $1.75.

IX. RESPONSIBILITY IN MENTAL DISEASE. By HENRY MAUDSLEY, M. D. 1 vol., 12mo. Cloth. Price, $1.50.

X. THE SCIENCE OF LAW. By Prof. SHELDON AMOS. 1 vol., 12mo. Cloth. Price, $1.75.

XI. ANIMAL MECHANISM. A TREATISE ON TERRESTRIAL AND AËRIAL LOCOMOTION. By E. J. MAREY. With 117 Illustrations. Price, $1.75.

XII. THE HISTORY OF THE CONFLICT BETWEEN RELIGION AND SCIENCE. By JOHN WM. DRAPER, M. D., LL. D., author of “The Intellectual Development of Europe.” Price, $1.75.

XIII. THE DOCTRINE OF DESCENT, AND DARWINISM. By Prof. OSCAR SCHMIDT, Strasburg University. Price, $1.50.

XIV. THE CHEMISTRY OF LIGHT AND PHOTOGRAPHY. IN ITS APPLICATION TO ART, SCIENCE, AND INDUSTRY. By Dr. HERMANN VOGEL. 100 Illustrations. Price, $2.00.

XV. FUNGI; THEIR NATURE, INFLUENCE, AND USES. By M. C. COOKE, M. A., LL. D. Edited by Rev. M. J. BERKELEY, M. A., F. L. S. With 109 Illustrations. Price, $1.50.

XVI. THE LIFE AND GROWTH OF LANGUAGE. By Prof. W. D. WHITNEY, of Yale College. Price, $1.50.

XVII. THE NATURE OF LIGHT, WITH A GENERAL ACCOUNT OF PHYSICAL OPTICS. By Dr. EUGENE LOMMEL, Professor of Physics in the University of Erlangen. With 188 Illustrations and a Plate of Spectra in Chromo-lithography. (_In press._)

THE INTERNATIONAL SCIENTIFIC SERIES.

THE

CONSERVATION OF ENERGY.

BY

BALFOUR STEWART, LL. D., F.R.S.,
PROFESSOR OF NATURAL PHILOSOPHY AT THE OWENS COLLEGE, MANCHESTER.

_WITH AN APPENDIX_,

TREATING OF THE VITAL AND MENTAL APPLICATIONS OF THE
DOCTRINE

NEW YORK:
D. APPLETON AND COMPANY,
549 & 551 BROADWAY.
1875.

ENTERED, according to Act of Congress, in the year 1874, by
D. APPLETON & COMPANY,
In the Office of the Librarian of Congress, at Washington.

NOTE TO THE AMERICAN EDITION.

The great prominence which the modern doctrine of the Conservation of Energy or Correlation of Forces has lately assumed in the world of thought, has made a simple and popular explanation of the subject very desirable. The present work of Dr. Balfour Stewart, contributed to the International Scientific Series, fully meets this requirement, as it is probably the clearest and most elementary statement of the question that has yet been attempted. Simple in language, copious and familiar in illustration, and remarkably lucid in the presentation of facts and principles, his little treatise forms just the introduction to the great problem of the interaction of natural forces that is required by general readers. But Professor Stewart having confined himself mainly to the physical aspects of the subject, it was desirable that his views should be supplemented by a statement of the operation of the principle in the spheres of life and mind. An Appendix has, accordingly, been added to the American edition of Dr. Stewart’s work, in which these applications of the law are considered.

Professor Joseph Le Conte published a very able essay fourteen years ago on the Correlation of the Physical and Vital Forces, which was extensively reprinted abroad, and placed the name of the author among the leading interpreters of the subject. His mode of presenting it was regarded as peculiarly happy, and was widely adopted by other writers. After further investigations and more mature reflection, he has recently restated his views, and has kindly furnished the revised essay for insertion in this volume.

Professor A. Bain, the celebrated Psychologist of Aberdeen, who has done so much to advance the study of mind in its physiological relations, prepared an interesting lecture not long ago on the “Correlation of the Nervous and Mental Forces,” which was read with much interest at the time of its publication, and is now reprinted as a suitable exposition of that branch of the subject. These two essays, by carrying out the principle in the field of vital and mental phenomena, will serve to give completeness and much greater value to the present volume.

NEW YORK, _December, 1873_.