viii CONTENTS OF THE SECOND VOLUME. 

 CHAPTER VI. THE INSTRUMENTS AND AIDS OF ASTRONOMY 



DURING THE NEWTONIAN PERIOD. 



PAGE 



Sect. 1. Instruments . 272 



Sect. 2. Observatories 282 



Sect. 3. Scientific Societies 285 



Sect. 4. Patrons of Astronomy .... 286 



Sect. 5. Astronomical Expeditions . 



Sect. 6. Present State of Astronomy 



THE SECONDARY MECHANICAL SCIENCES. 



BOOK VIII. 



HISTORY OF ACOUSTICS 

 Introduction ......... 323 



CHAPTER I. PRELUDE TO THE SOLUTION OP PROBLEMS IN 



ACOUSTICS . . . 325 



CHAPTER II. PROBLEM OF THE VIBRATIONS OF STRINGS . 332 

 CHAPTER III. PROBLEM OF THE PROPAGATION OF SOUND 340 



CHAPTER IV. PROBLEM OF DIFFERENT SOUNDS OF THE 



SAME STRING .... 348 



CHAPTER V. PROBLEM OF THE SOUNDS OF PIPES . 352 



CHAPTER VI. PROBLEM OF DIFFERENT MODES OF VIBRA- 

 TION OF BODIES IN GENERAL . .357 



BOOK IX. 



HISTORY OF OPTICS, FORMAL AND PHYSICAL. 

 Introduction . 371 



FORMAL OPTICS: 

 CHAPTER I. PRIMARY INDUCTION OF OPTICS. RAYS OF 



LIGHT AND LAWS OF REFLECTION . . 374 



CHAPTER II. DISCOVERY OF THE LAW OF REFRACTION . 376 



