THE WONDERS OF OPTICS. ------------------------------------------------------------------------ [Illustration: Spectrum showing the absorptive power of Sodium vapour (Fig. 6). ] [Illustration: Solar Spectrum (Fig. 5). ] [Illustration: Action of a prism on a ray of light (Fig. 7). Eng.^d by A. Robin N.Y. ] ------------------------------------------------------------------------ THE WONDERS OF OPTICS. BY F. MARION. TRANSLATED FROM THE FRENCH, AND EDITED BY CHARLES W. QUIN, F.C.S. ILLUSTRATED WITH SEVENTY ENGRAVINGS ON WOOD, AND A COLOURED FRONTISPIECE. -------------- NEW YORK: CHARLES SCRIBNER’S SONS, SUCCESSORS TO SCRIBNER, ARMSTRONG, & CO. ------------------------------------------------------------------------ PREFACE. -------------- THE present work needs but little introduction to the English public. The author, M. F. Marion, who holds a high official scientific position in Paris, is well known, especially in Europe, as a popular writer on the “Wonders of Optics,” and kindred subjects. As a rule, the original text has been strictly adhered to by the Translator, but in a few instances certain anecdotes of a local character have been altered so as to be more generally applicable, or condensed to make room for the chapter on the Spectroscope, which is entirely original. ------------------------------------------------------------------------ CONTENTS. -------------- PART I. THE PHENOMENA OF VISION. CHAPTER I. PAGE THE EYE 15 CHAPTER II. THE STRUCTURE OF THE EYE 22 CHAPTER III. THE ERRORS OF THE EYE 30 CHAPTER IV. OPTICAL ILLUSIONS 36 CHAPTER V. THE APPRECIATION OF COLOUR 44 CHAPTER VI. ILLUSIONS CAUSED BY LIGHT ITSELF 53 CHAPTER VII. THE INFLUENCE OF THE IMAGINATION 60 -------------- PART II. THE LAWS OF LIGHT. CHAPTER I.