CHAPTER VI

.--PROBLEM OF DIFFERENT MODES OF VIBRATION OF BODIES IN

GENERAL. 41

## BOOK IX.

HISTORY OF OPTICS, FORMAL AND PHYSICAL.

Introduction. 51 {8}

_FORMAL OPTICS._

## CHAPTER I .--PRIMARY INDUCTION OF OPTICS.--RAYS OF LIGHT AND LAWS

OF REFLECTION. 53

## CHAPTER II .--DISCOVERY OF THE LAW OF REFRACTION. 54

## CHAPTER III .--DISCOVERY OF THE LAW OF DISPERSION BY REFRACTION. 58

## CHAPTER IV .--DISCOVERY OF ACHROMATISM. 66

## CHAPTER V .--DISCOVERY OF THE LAWS OF DOUBLE REFRACTION. 69

## CHAPTER VI .--DISCOVERY OF THE LAWS OF POLARIZATION. 72

## CHAPTER VII .--DISCOVERY OF THE LAWS OF THE COLORS OF THIN PLATES. 76

## CHAPTER VIII .--ATTEMPTS TO DISCOVER THE LAWS OF OTHER PHENOMENA. 78

## CHAPTER IX .--DISCOVERY OF THE LAWS OF PHENOMENA OF DIPOLARIZED

LIGHT. 80

_PHYSICAL OPTICS._

## CHAPTER X .--PRELUDE TO THE EPOCH OF YOUNG AND FRESNEL. 85

##