Relation to Philosophy Relation to Mathematics Relation to the Technical Operations of the Dyer Relation to Physiology and Pathology Relation to Natural History Relation to General Physics Relation to the Theory of Music Concluding Observations on Terminology PART VI. EFFECT OF COLOUR WITH REFERENCE TO MORAL ASSOCIATIONS. Yellow Red-Yellow Yellow-Red Blue Red-Blue Blue-Red Red Green Completeness and Harmony Characteristic Combinations Yellow and Blue Yellow and Red Blue and Red Yellow-Red and Blue-Red Combinations Non-Characteristic Relation of the Combinations to Light and Dark Considerations derived from the Evidence of Experience and History Æsthetic Influence Chiaro-Scuro Tendency to Colour Keeping Colouring Colour in General Nature Colour of Particular Objects Characteristic Colouring Harmonious Colouring Genuine Tone False Tone Weak Colouring The Motley Dread of Theory Ultimate Aim Grounds Pigments Allegorical, Symbolical, Mystical Application of Colour Concluding Observations OUTLINE OF A THEORY OF COLOURS. "Si vera nostra sunt aut falsa, erunt talia, licet nostra per vitam defendimus. Post fata nostra pueri qui nunc ludunt nostri judices erunt." INTRODUCTION. The desire of knowledge is first stimulated in us when remarkable phenomena attract our attention. In order that this attention be continued, it is necessary that we should feel some interest in exercising it, and thus by degrees we become better acquainted with the object of our curiosity. During this process of observation we remark at first only a vast variety which presses indiscriminately on our view; we are forced to separate, to distinguish, and again to combine; by which means at last a certain order arises which admits of being surveyed with more or less satisfaction. To accomplish this, only in a certain degree, in any department, requires an unremitting and close application; and we find, for this reason, that men prefer substituting a general theoretical view, or some system of explanation, for the facts themselves, instead of taking the trouble to make themselves first acquainted with cases in detail and then constructing a whole. The attempt to describe and class the phenomena of colours has been only twice made: first by Theophrastus,[1] and in modern times by Boyle. The pretensions of the present essay to the third place will hardly be disputed.