The exercises should begin and end with tonic harmony.

When the counterpoint begins on the first quarter it must form a perfect
consonance with the cantus firmus. When on the second or fourth quarter,
any consonance may be used.

All previous rules are to be regarded, unless exceptions are made.

At least one of the first three quarter-notes of a measure should be left
degreewise. [Fig. 43.]

[Illustration: Fig. 43.]

The last quarter of a measure is usually left degreewise. If approached by
a skip or by a degreewise progression of at least two quarter-notes, it may
be left by a skip in the opposite direction from which it was approached. A
skip of a third in the same direction is also good when this skip is
preceded by a skip of a third (_d_). [Fig. 44.]

[Illustration: Fig. 44.]

Parts may cross occasionally.

The use of non-harmonic tones, as in Fig. 45, is good in either part. At
_a_ the passing-tone, instead of progressing directly to the adjacent
chord-tone, skips a third to the other side of it and then returns. The
embellishment is treated in the same way, but is most effective when the
principal tone is the leading-tone, as at _b_. In both cases the
counterpoint should continue degreewise through the chord-tone. [Fig. 45.]