urbance of the natural order of
register:

[Music: Overlaying. Crossing. Enclosure.]

In choosing one of these three methods the following points must not
be forgotten: a) the register of a particular isolated chord; the soft
and weak register of an instrument should not be coupled with the
powerful and piercing range of another:

[Music:

Overlaying.
Oboe too
piercing.

Crossing.
Low notes
of the flute
too weak.

Enclosure.
Bassoon too
prominent.]

b) In a succession of chords the general progression of parts must be
considered; one tone quality should be devoted to the stationary and
another to the moving parts:

[Music]

When chords are in widely-divided four-part harmony notes may be
allotted in pairs to two different tone qualities, adhering to the
normal order of register:

Good: [Music] etc.

Any other distribution will result unquestionably in a grievous lack
of relationship between registers:

To be avoided: [Music] etc.

If one tone quality is to be enclosed, it must be between two
different timbres:

Good: [Music] etc.

It is possible to lend four distinct timbres to a chord in
widely-divided four-part harmony, though such a chord will possess no
uniformity in colour; but the higher the registers of the different
instruments are placed, the less perceptible becomes the space which
separates them:

[Music: Fairly good Better Still better]

The use of four different timbres in close four-part harmony is to be
avoided, as the respective registers will not correspond:

[Music: Bad Better Still slightly better]

_Note._ In _Mozart and Salieri_, which is only scored for 1
Fl., 1 Ob., 1 Cl. and 1 Fag., wood-wind chords in four-part
harmony are of necessity devoted to these four different
timbres.

The same rules apply to writing in three-part harmony, which is the
most customary form when it is a question of establishing a harmonic
basis, the lowest register of which is entrusted to another group of
instruments (strings _arco_ or _pizz._, for example). Chords in
three-part harmony are generally given to two instruments of one
timbre and a third instrument of another, but never to three different
timbres. Overlaying of parts is the best course to adopt:

[Music] etc.

The use of crossing and enclosure of parts (which in a way amount to
the same thing) must depend on the manner of their progression:

[Music: Enclosure]

B. _Wood-wind in three's._ Here th