" " " [[125]]--Undulating rhythm in the strings as harmonic basis (cf. Ex. 271).

In a _forte_ or _sfp_ chord, where one or two of the upper notes is held, either sustained or _tremolando_, the balance of tone must still be maintained, as in the following example:

[Music:

Vns I VnII Violas D. ba.s.ses]

Wood-wind harmony.

Before entering upon this section of the work I would remind the reader of the general principles laid down in the beginning of the chapter.

Harmonic texture, composed of plain chords or ornamental designs, simple or contrapuntal in character, must possess a resonance equally distributed throughout. This may be obtained by the following means:

1. Instruments forming chords must be used continuously in the same way during a given pa.s.sage, that is to say they must be doubled or not throughout, except when one of the harmonic parts is to be made prominent:

To be avoided: [Music]

2. The normal order of register must be followed, except in the case of crossing or enclosure of parts, which will be discussed later on:

To be avoided: [Music]

3. Corresponding or adjacent registers should be made to coincide except for certain colour effects:

To be avoided: [Music]

The second flute will sound too weak and the oboes too piercing.

4. Concords (octaves, thirds and sixths) and not discords (fifths, fourths, seconds and sevenths), should be given to instruments of the same kind or colour, except when discords are to be emphasised. This rule should be specially observed in writing for the oboe with its penetrating quality of tone:

To be avoided: [Music]

Four-part and three-part harmony.

Harmonic writing for the wood-wind may be considered from two points of view: a) instruments in pairs, 2 Fl., 2 Ob., 2 Cl., 2 f.a.g.; and b) instruments in three's, 3 Fl., 2 Ob., Eng. horn, 3 Cl., 2 f.a.g., C-f.a.g.

A. _In pairs._ There are three ways of distribution: 1.

_Superposition_ or _overlaying_ (strictly following the normal order of register), 2. _Crossing_, and 3. _Enclosure_ of parts. The last two methods involve a certain disturbance 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.

Ba.s.soon 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 relations.h.i.+p 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 s.p.a.ce 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 f.a.g., 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 establis.h.i.+ng 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 the distribution of chords in close three-part harmony is self-evident; any grouping of three instruments of the same timbre is sure to sound well:

[Music]

also: [Music]

[Music]