There are certain elementary types of unity which are necessary for clarity of musical meaning. These will be referred to as textures. They are types of "togetherness" in musical action, and are particularly necessary to orchestral writing because of the many diverse sounds and motor potentialities which, if left unorganized, would incline toward confusion. The orchestra, more than any other medium, profits most from clear and definite design (positive texture).
The application of the word "texture" to music may need to be defended. The main definition as given in the dictionary is: "texture — the peculiar disposition of the constituent parts of any body; the manner in which they are disposed, arranged or united; structure in general." Surely this definition includes music (a body of sound).
Each of these textural types will be fully explained and illustrated and study projects suggested. After the several textural projects have been completed it should become clear that every score must necessarily utilize one or another of the textures at some point in its progress, since they are indispensable sources of unity.