the fifths of the triads on I, IV and vii°. The last tone should return one
degree (_b_). [Fig. 9.]

Do not move more than an octave in one direction in two skips. [Fig. 9_c_.]

[Illustration: Fig. 9.]

Covered fifths and octaves, except from I to V, or V to I, are forbidden.
[Fig. 10.]

[Illustration: Fig. 10.]

Both parts skipping in contrary motion to a fifth or octave should be
avoided in two-part writing. [Fig. 11.]

[Illustration: Fig. 11.]

Avoid consecutive perfect intervals. [Fig. 12.]

[Illustration: Fig. 12.]

The augmented fourth (Tritone) is not only considered bad as a melodic
interval by some authorities, but its appearance between different parts in
successive intervals is also prohibited. This prohibition, however, holds
good only when the chords in which it appears are in fundamental position,
as in Fig. 13_a_. This is shown by the fact, that if one part skips as at
_b_, there is no unpleasant effect.

[Illustration: Fig. 13.]