opinions of the Press on the l7iternational Scientific Series ^ 



VII. 



The Conservation of Energy. 



By BALFOUR STEWART, LL. D. 

 With an Appendix, treating of the Vital and Mental Applications of 

 the Doctrine, 



I vol., i2mo. Cloth Price, $1.50. 



Note to the A 7}ierican 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. Bal- 

 four Stewart, contributed to the 'International Scientific Series,' fully meets this re- 

 quirement, 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 re- 

 quired by general readers. But Prof. 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. 



*'Prof 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 re- 

 stated his views, and has kindly furnished the revised essay for insertion in this volume. 



"Prof. 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 lec- 

 ture 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 prin- 

 ciple in the field of vital and mental phen omena, will serve to give completeness and 

 much greater value to the present volume." 



"The great physical generalization called * The Conservation of Energy' is in an 

 intermediate state. It is so new that all kinds of false ideas are prevalent about it; it 

 is so exact that these cannot be tolerated ; and thus its circumstances are such as to 

 make so thorough and simple a treatise as this, by Prof. Balfour Stewart, a boon to 

 science antl the world at large. 



*' The scheme of the book is simple, as is naturally the case when the subject-mat- 

 ter comprehends but one single law of Nature and its manifestations. The first two 

 chapters are devoted to the consideration of mechanical energy and its change into 

 heat, Prof Stewart rightly devoting special attention to these two forms of energy, 

 compared with which all others are insignificant in practical, if not in theoretical, im- 

 portance. The remaining forms of energy are then explained, and the law of its con- 

 servation is stated, and its operation traced through all varieties of transmutations. An 

 historical sketch of the progress of the science and an examination of Prof Thomson's 

 correlative theory of the 'Dissipation of Energy ' follow ; and the work concludes with 

 a chapter on the 'Position of Life,' which is closely connected with a well-known essay 

 written some years ago by Prof Stewart and Mr. I.ockyer. The style is all that it 

 should be; it is difficult to understand how so much information can be contained in so 

 few words. Prof Stewart could not have been nearly so successful in this respect had 

 he been in any degree a pedant. No such writer would permit himself to use the 

 quaint language and still quainter similes and and illustrations that make the book so 

 readable, and yet there is scarcely one that is out of place, or illegitimately used, or 

 likely to mislead." — Saturday Review. 



D. APPLETON & CO., Publishers, 549 & 551 Broadway, N. Y. 



