DICTIONARY OF MUSIC - El Atril

502 INVERTIBLE COUNTERPOINT INVEETIBLE COUNTERPOINT
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still more cous})icuou3 among melodic devices,
by which harmonic intention is implied, is that
which in all its forms may be called the arpeggio
device, i.e. moving from note to note of a chord
till it be completely inferred
In these instances of inferred diminished and
dominant sevenths it will be seen that it is
enough to indicate the two characteristic notes
of each chord, the rest being omitted. This
principle is easier to embody in two-part writing,
where all the melodic deidces just enumerated
may be supjilemented by a characteristic note
in the second part that shall make the progression
still clearer. For instance, if the dominant
seventh be added to the leading note in the example
at the top of this page, the progression
is confirmed, and a sure foundation for good
double counterpoint will be formed.
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The same principles of harmonic implication
evidently guided Bach in his construction of
such masterly triple counterpoint as the following
:—
From No. 3 of the 'Forty-eight.'
in which a bold leap to C sharp in the second
bar enaljles him to retain the vigour and ful-
ness of a complete common chord without the
smallest risk of ambiguity. The reader will
have perceived that in an important sense it
becomes really easier to write good invertible
counterpoint in many parts than in two. For,
as the parts increase, the means of harmonic
clearness manifestly increase also. Thus, a
chord of the dominant or diminished seventh
is not liable to the ambiguity in inversion that
besets a pjlain common chord. And from this
the student may argue backwards and discover
that in three -pjart counterpoint, and even in
two, incomplete or implied chords of the seventh
will often serve far better than complete or
implied common chords, and will make his
harmonic purpose quite clear. A splendid
instance of this device is to be found in the
following triple counterpoint taken from Bach's
great G minor organ fugue :
which is chiefly built on incomplete chords of
the seventh.
Of the many varieties of inversion at other
intervals (mentioned in the article Inversion)
two are to be singled out as the most useful.
Double Oounterpoint rxt the Tenth.—The chief
claim of this variety to special consideration is
to be found in the fact, pointed out by the
1 6 th century theorists as well as those of to-day,
that it is possible to use the model (or jrrvncijpal)
and its inversion (or reply) simultaneously, thus
making a three-piart result. Before Palestrina
was born, Ornitlioparcus wrote :
' The most
famous manner of the Counter-point (as saith
Franchinus) is, if the Base goe together with
the Mea.ne, or any other Voyce, being also
distant by a tenth, whilst the Tenor doe goe
in Concord to both.' To achieve this, consecutive
thirds and sixths are obviously banned
in the model. This is its chief condition, and
two parts in well-planned contrary and oblique
motion generally allow not only of this valuable
inversion in its simple form, but also of various
applications of what are kno^\m as added thirds,
in which the advantages of lucidity and economy
are combined with those of richness and strengtli
which the subjects naturally gain by being
doubled in thirds or sixths. Albrechtsberger
invents the following example in his treatise,
which he is able to translate into four parts
thus :
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