Chapter Vii.--Relative Motion and Absolute Motion 107

The Principle of Relative Motion 107 Newton's Argument 108

CHAPTER VIII.--Energy and Thermodynamics 115 Energetics 115 Thermodynamics 119 General Conclusions on Part III 123

PART IV. Nature

CHAPTER IX.--Hypotheses in Physics 127 The Rôle of Experiment and Generalization 127 The Unity of Nature 130 The Rôle of Hypothesis 133 Origin of Mathematical Physics 136