matched by the multiplicity of problems in the physical and philosophical sciences with which it is connected. Without attempting to enumerate all of the scientific problems related to this subject, it may be of interest to briefly summarize those which are most prominent. At the outset we have such purely physical questions as the nature of light, the cause of its emission, the mode of its propagation, the difference in the waves which give rise to the various color sensations, the principles of absorption, of reflection and of refraction, and the nature of material surfaces whereby they acquire their characteristic colors. Then comes the physiology of the eye, including its structure and its function and involving the much discussed questions of primary and secondary colors, and these are closely related to the psychological or psycho-physical study of the nature, duration and delicacy of color vision and color judgment. Next to these comes the study of pigments and of the chromatic effects of their mixture, essentially a chemical and technical question, and finally, the most important of all, the purely psychological or aesthetic problem touching the harmonization and grouping of the various colors and their modifications. The recent advance made in experimental psychology has given an impetus to the study of the whole subject and we may reasonably expect that rational explanations may be found for questions in aesthetics hitherto considered purely arbitrary.
It will be readily seen that there must be a well developed and carefully trained color sense at the basis of an education which is to lead to the consideration of these and similar chromatic problems. As in the development of any special perceptive power, a great deal depends upon making a beginning
