ribution of intermediate parts is a
question of the greatest importance. Nothing is worse than writing
chords, the upper and lower parts of which are separated by wide,
empty intervals, especially in _forte_ passages; in _piano_ passages
such distribution may be possible. Progression in contrary motion, the
upper and lower parts diverging by degrees gives rise to the gradual
addition of extra parts occupying the middle register:

Schematic Example: [Music]

When the voices converge, the middle parts are eliminated one by one:

Schematic Example: [Music]

String harmony.

It is an incontrovertible rule that the resonance of different
harmonic parts must be equally balanced, but this balance will be less
noticeable in short sharp chords than in those which are connected and
sustained. Both these cases will be studied separately. In the first
case, in order to increase the number of harmonic parts, each
instrument in the string group may be provided with double notes or
chords of three and four notes. In the second case, the resources are
limited to double notes _unis_, or division of parts.

A. _Short chords._ Chords of three or four notes can only be executed
rapidly on the strings.

_Note._ It is true that the two upper notes of a chord can
be sustained and held a long time; this, however, involves
complications and will be considered later.

Short chords, _arco_, only sound well when played _forte_ (_sf_), and
when they can be supported by wind instruments. In the execution of
double notes and chords of three and four notes on the strings,
balance, perfect distribution of tone, and correct progression of
parts are of minor importance. What must be considered before
everything is the resonance of the chords themselves, and the degree
of ease with which they can be played. Those comprising notes on the
gut strings are the most powerful. Chords played on several strings
are usually assigned to 1st and 2nd violins and violas, the
different notes being divided between them according to ease in
execution and the demands of resonance. On account of its low register
the 'cello is rarely called upon to play chords on three or four
strings, and is usually allotted the lowest note of the chord in
company with the double bass. Chords on the latter instrument are even
more uncommon, but it may supply the octave on an uncovered string.

_Examples:_

No. 97. _Snegourotchka_ [[171]]; cf. also before [[140