PHYSICAL SIGNIFICANCE
OF ENTROPY
OR OF THE SECOND LAW

BY

Professor of Mechanical Engineering,
Lehigh University

NEW YORK

D. VAN NOSTRAND COMPANY
23 MURRAY AND 27 WARREN STREETS
1910

COPYRIGHT, 1910,
BY
JOSEPH FREDERICK KLEIN

THE SCIENTIFIC PRESS
ROBERT DRUMMOND AND COMPANY
BROOKLYN, N. Y.

PREFACE

In this little book the author has in the main sought to present theinterpretation reached by BOLTZMANN and by PLANCK. The writer has drawnmost heavily upon PLANCK, for he is at once the clearest expositor ofBOLTZMANN and an original and important contributor. Now these twoinvestigators reach the result that entropy of any physical state is thelogarithm of the probability of the state, and this probability isidentical with the number of "complexions" of the state. This number isthe measure of the permutability of certain elements of the state and inthis sense entropy is the "measure of the disorder of the motions of asystem of mass points." To realize more fully the ultimate nature ofentropy, the writer has, in the light of these definitions, interpretedsome well-known and much-discussed thermodynamic occurrences andstatements. A brief outline of the general procedure followed will befound on p. 3, while a fuller synopsis is of course given in theaccompanying table of contents.

J. F. Klein.

Lehigh University, October, 1910.

TABLE OF CONTENTS