Again. THE END. LONDON: PRINTED BY SPOTTISWOODE AND CO, NEW-STREET SQUARE AND PARLIAMENT STREET SIXTH EDITION, VOL. 1. LONDON: LONGMANS, GREEN, AND CO. 1879. All rights reserved. PREFACE TO THE COLOUR AND CHEMICAL CONSTITUTION OF NATURE. [Footnote: 'Fortnightly Review,' 1865, vol. Xxii. P. 9. SIR JOHN.