CONTENTS. 



PREFACE, ........ v 



INTRODUCTION, . . . . . . xi 



THE CORRELATION OF PHYSICAL FORCES, BY W. R. GROYE. 



Preface, ....... 3 



I. Introductory Remarks, .... 9 



II. Motion, . . . . . .25 



III. Heat, ...... 39 



IV. Electricity, ...... 83 



V. Light, 110 



VI. Magnetism, .142 



VH. Chemical Affinity, . . . .152 



VIII. Other Modes of Force, . . . .169 



IX. Concluding Remarks, . . . .ITS 



Notes and References, ..... 200 



ON THE INTERACTION OF NATURAL FORCES, BY PROF. 



HELMHOLTZ, , . . . . 211 



REMARKS ON THE FORCES OF INORGANIC NATURE, By DR. 



J. R. MAYER, ... .251 



