DICTIONARY OF MUSIC - El Atril

318 HARMONY HARMONY
according to their roots or fundamental basses
has been since generally adopted.
By the beginning of the 18th century the
practice of grouping the harmonic elements of
music or chonls according to the keys to which
they belong, which is called observing the laws
of tonality, was tolerably universal. Composers
had for the most part moved sufficiently far
away from the influence of the old ecclesiastical
system to be able to realise the first principles
of the new secular school. These principles are
essential to instrumental music, and it is chiefly
in relation to that large department of the
modern art that they must be considered. Under
the conditions of modern harmony the harmonic
basis of any passage is not intellectually appre-
ciable unless the principle of the relations of
the chords composing it to one another through
a common tonic be observed. Thus if in the
middle of a succession of chords in C a chord
appears which cannot be referred to that key,
the passage is inconsistent and obscure ; but if
this chord is followed by others which can with
it be referred to a different key, modulation has
been efl'ected, and the succession is rendered in-
telligible by its relation to a fresh tonic in the
place of C. The range of chords which were
recognised as characteristic of any given key
was at first very limited, and it was soon perceived
that some notes of the scale served as the
bass to a larger number and a more important
class of them, the Dominant appearing as the
most important, as the generator of the larger
number of diatonic chords ; and since it also contains
in its compound tone the notes which are
most remote from the chord of the tonic, the
artistic sense of musicians led them to regard
the Dominant and the Tonic as the opposite
poles of the harmonic circle of the key, and no
progression was sufficiently definable to stand in
a position of tonal importance in a movement
unless the two poles were somehow indicated.
That is to say, if a movement is to be cast upon
certain prominent successions of keys to which
other keys are to be subsidiary, those which are
to stand prominently forward must be defined
by some sort of contrast based on the alternation
of Tonic and Dominant harmony. It is
probably for this reason that the key of the
Subdominant is unsatisfactory as a balance or
complementary key of a movement, since in progressing
to its Dominant to verify the tonality,
the mind of an intelligent listener recognises the
original Tonic again, and thus the force of the
intended contrast is weakened. This, as has
been above indicated, is frequently found in
works of the early harmonic period, while composers
were still searching for the scale which
should give them a major Dominant chord, and
the effect of such movements is curiously wandering
and vague. The use of the Dominant
as the complementary key becomes frequent in
works of the latter portion of the 17th century,
and early in the next, as in Bach
as in Corelli ;
and Handel, it is recognised as a matter of
course ; in the time of Haydn and Mozart so
much strain was put upon it as a centre, that
it began to assume the character of a conven-
tionalism and to lose its force. Beethoven consequently
began very early to enlarge the range
of harmonic bases of the key by the use of chords
which properly belonged to other nearly related
keys, and on his lines composers have since
continued to work. The Tonic and Dominant
centres are still apparently inevitable, but they
are supplemented by an enlarged range of harmonic
roots giving chrojnaticcombinationswhich
are affiliated on the original Tonic through their
relations to the more important notes of the
scale which that Tonic represents, and can be
therefore used without obscuring the tonality.
As examples of this may be taken the minor
seventh on the tonic, which properly belongs
to the nearly allied key of the subdominant
a major concord on the supertonie, with the
minor seventh superimposed, which properly
belong to the Dominant key ; the major chord
on the mediant, which properly belongs to the
key of the relative minor represented by the
chord of the submediant, and so on.
Bach's use of harmony was a perfect adaptation
to it of the principles of polyphony. He
resumed the principle of making the harmony
ostensibly the sum of the independent parts,
but with this difference from the old style,
that the harmoniesreally formed the substratum,
and that their progressions were as intelligible
as tlie melodies of which they seemed to be the
result. From such a principle sprang an immense
extension of the range of harmonic combinations.
The essential fundamental chords
are but few, and must remain so, but the combinations
which can be made to represent them
on the polyphonic principle are almost infinite.
By the use of chromatic passing and preliminary
notes, by retardations, and by simple chromatic
alterations of the notes of chords according
to their melodic significance, combinations are
arrived at such as puzzled and do continue to
puzzle theorists who regard harmony as so many
unchangeable lumps of chords which cannot be
admitted in music unless a fundamental bass
can be found for them. Thus the chord of the
augmented sixth is probably nothing more than
the modification of a melodic progression of one
or two parts at the point where naturally they
would be either a major or minor sixth from
one another, the downward tendency of the
one and the upward tendency of the other
causing them to be respectively flattened and
sharpened to make them approach nearer to
the notes to wljich they are moving. In the
case of the augmented sixth on the flat second
of the key, there is only one note to be
altered ; and as that note is constantly altered
in this fashion in other combinations—namely