Preface.

The subjects of the next division of the book are as follows. The last chapter is devoted to the explanation of various phenomena by means of the hypothesis that bodies consist of molecules, and that the motion of these molecules constitutes the heat of those bodies.

In order to bring the treatment of these subjects within the limits of this text-book, it has been found necessary to omit everything which is not an essential part of the intellectual process by which the doctrines of heat have been developed, or which does not materially assist the student in forming his own judgment on these doctrines.

For this reason, no account is given of several very important experiments, and many illustrations of the theory of heat by means of natural phenomena are omitted. The student, however, will find this part of the subject treated at greater length in several excellent works on the same subject which have lately appeared.

A full account of the most important experiments on the effects of heat will be found in Dixon’s Treatise on Heat (Hodges & Smith, 1849).

Professor Balfour Stewart’s treatise contains all that is necessary to be known in order to conduct experiments on heat. The student may also be referred to Deschanel’s Natural Philosophy, Part II, translated by Professor Everett, who has added a chapter on thermodynamics The branch of physics dealing with the relationships between heat and other forms of energy.; to Professor Rankine’s work on the Steam Engine, in which he will find the first systematic treatise on thermodynamics; to Professor Tait’s Thermodynamics, which contains a historical sketch of the subject as well as the mathematical investigations; and to Professor Tyndall’s work on Heat as a Mode of Motion, in which the doctrines of the science are forcibly impressed on the mind by well-chosen illustrative experiments. The original memoirs of Professor Clausius, one of the founders of the modern science of thermodynamics, have been edited in English by Professor Hirst.