AUTHOR'S PREFACE. MANY representations having been made to the author from different quarters that the numerous papers"On the Me- chanical Theory of Heat,"which he had published at different times during a series of years,were inaccessible to many who, from the widespread interest now felt in this theory,were anxious to study them,he undertook some years back to publish a complete collection of his papers relating to the subject. As a fresh edition of this book has now become necessary, he has determined to give it an entirely new form.The Mechanical Theory of Heat,in its present development,forms already an extensive and independent branch of science. But it is not easy to study such a subject from a series of separate papers,which,having been published at different times,are unconnected in their form,although they agree in their contents.Notes and additions,however freely used to explain and supplement the papers,do not wholly over- come the difficulty.The author,therefore,thought it best so to re-model the papers that they might form a connected whole,and enable the work to become a text-book of the science.He felt himself the more bound to do this because GoogleAUTHOR'S PREFACE. MANY representations having been made to the author from different quarters that the numerous papers CI On the Me￾chanical Theory of Heat," which he had published at different times during a series of years, were inaccessible to many who, from the widespread interest now felt in this theory, were anxious to study them, he undertook some years back to publish a complete collection of his papers relating to the subject. As a fresh edition of this book has now become necessary, he has determined to give it an entirely new form. The Mechanical Theory of Heat, in its present development, furms already an extensive and independent branch of science. But it is not easy to study such a subject from a series of separate papers, which, having been published at different times, are unconnected in their form, although they agree in their contents. Notes and additions, however freely used to explain and supplement tIle papers, do not wholly over￾come the difficulty. The author, therefore, thought it best so to re-model the papers that they might form a connected whole, and enable the work to become a text-book of the science. He felt himself the more bound to do this because Digitized by Coogle