Transcriber’s Notes: Underscores “_” before and after a word or phrase indicate _italics_ in the original text. Equal signs “=” before and after a word or phrase indicate =bold= in the original text. Small capitals have been converted to SOLID capitals. Illustrations have been moved so they do not break up paragraphs. Old or antiquated spellings have been preserved. Typographical and punctuation errors have been silently corrected. The list of works by Sir David Brewster has been moved form the first page to the end of the text. [Illustration] THE KALEIDOSCOPE, ITS HISTORY, THEORY, AND CONSTRUCTION. WITH ITS APPLICATION TO THE FINE AND USEFUL ARTS. BY SIR DAVID BREWSTER, K.H., M.A., D.C.L., F.R.S., V.P.R.S., EDIN., M.R.I.A., F.G.S., F.R.A.S., ASSOCIATE OF THE IMPERIAL INSTITUTE OF FRANCE, HONORARY OR CORRESPONDING MEMBER OF THE ACADEMIES OF PETERSBURGH, VIENNA, BERLIN, COPENHAGEN, STOCKHOLM, BRUSSELS, GOTTINGEN, MODENA, AND OF THE NATIONAL INSTITUTE OF WASHINGTON, AND PRINCIPAL OF THE UNITED COLLEGES OF ST. SALVATOR AND ST. LEONARD, ST. ANDREWS. _Nihil tangit quod non ornat._ [Illustration] Third Edition, greatly enlarged. WITH FIFTY-SIX WOOD ENGRAVINGS AND ONE PLATE. LONDON: JOHN CAMDEN HOTTEN, PICCADILLY. 1870. CONTENTS. PAGE INTRODUCTION—HISTORY OF THE KALEIDOSCOPE, 1 CHAP. I.—PRELIMINARY PRINCIPLES RESPECTING THE EFFECTS OF COMBINING TWO PLAIN MIRRORS, 9 II.—ON THE PRINCIPLES OF THE KALEIDOSCOPE, AND THE FORMATION OF SYMMETRICAL PICTURES BY THE COMBINATION OF DIRECT AND INVERTED IMAGES, 16 III.—ON THE EFFECTS PRODUCED BY THE MOTION OF THE OBJECT AND THE MIRRORS, 26 IV.—ON THE EFFECTS PRODUCED UPON THE SYMMETRY OF THE PICTURE BY VARYING THE POSITION OF THE EYE, 37 V.—ON THE EFFECTS PRODUCED UPON THE SYMMETRY OF THE PICTURE BY VARYING THE POSITION OF THE OBJECT, 46 VI.—ON THE INTENSITY OF THE LIGHT IN DIFFERENT PARTS OF THE FIELD, AND ON THE EFFECTS PRODUCED BY VARYING THE LENGTH AND BREADTH OF THE REFLECTORS, 51 VII.—ON THE CONSTRUCTION AND USE OF THE SIMPLE KALEIDOSCOPE, 59