Glance again at Ex.

2, and note the contrast between the two halves of the first four measures, and between these and the following two measures.
These conditions are, of course, squarely opposed to each other, though their interaction is reciprocal rather than antagonistic; and, from what has been said, it is obvious that they are of equal importance.
Hence, as was declared on the second page, the great problem of the art-creator consists in so balancing their operations that neither may encroach upon the domain of the other.

For too constant and palpable Unity will inevitably paralyze interest; while too much Variety will as surely tend to obscure the distinctness of the design.
* * * * * * The workings of the principle of Unity (to which attention must first be given, because it appears to come first in the order of creation) are shown in the following elementary details of composition:-- (1) Music is not an art that deals with space, but with Time; therefore the units of its metrical structure are not inches and the like, but divisions of time, the basis of which is the _beat_.

The principle of Unity dictates that the beats which are associated in one and the same musical sentence shall be of equal duration.

Every musician admits the necessity of keeping "strict time"-- that is, marking the beats in regular, equal pulses.