In the first place, tones, unlike noises, are all pleasant. Although we cannot be sure why this is true, there can be little doubt, I think, that the regularity of the vibrations of the former, in contrast with the irregularity of the latter, is largely responsible. The clang, with its ordered complexity, is a stimulus that incites the sense organ and connected motor tracts to a unified and definite response, unlike noise, which creates confusion. The pleasure in the single tone is similar, in its causes, to the pleasure in the consonance of two tones. As we should expect from this analogy, the pleasure is greater in rich tones, which contain many partials, than in thin tones, which are relatively uninteresting. But the feeling of tones is something more than mere pleasantness; it is also a mood. Now this mood of tones is partly due to associations,--some superficial in character, like the pastoral quality of flute tones or the martial character of bugle tones, others more fundamental; but it has also a still deeper-lying root. For a sound stimulus awakens not only a sensory process in the ear, the correlative of which is a sensation, but also incipient motor reactions, which, if carried out, would be an emotion, but which, being too slight and diffuse, produce only what we call a mood. Every sensation has a meaning for the organism in an environment where it has constantly to be on its guard for danger or assistance; every sensation is therefore connected with the mechanism of reaction, with its attendant emotions. In ordinary experience, there are objects present to which the organism may actually respond, but in the aesthetic experience there are no real objects towards which a significant reaction can take place; in music, the source of the sound is obviously of no practical importance, while in such arts as painting and sculpture where interesting objects are represented, the objects themselves are absent; hence the reaction is never carried out, but remains incipient, a vague feeling which, finding no object upon which it may work itself off, is suffused upon the sensation. These sense feelings are the subtle, but basal, material of all beauty. The variety of moods expressed in tones is almost endless. When we experience them, they come to us as the inner life of the total concrete tones, but they depend actually upon the working together of all the tonal attributes,--color, quality, pitch, and loudness. There is the subtle intimacy of violin tones compared with the clear arresting ring of the trumpet; the emotional differences between qualities like C and G, too delicate for expression in words; the piercing excitement of the high, bright tones, compared with the earnest depth of the low, dull tones; the almost terrifying effect of loud tones compared with the soothing influence of soft tones.