e works in different ways without
illustrating any profound identities at all. Handel, for instance,
collected several of his favourite choruses in an enormous instrumental
concerto (see vol. 46 of the _Haendel-Gesellschaft_), and the result in the
case of a chorus like "Lift up your Heads" was ridiculous. Bach, however,
does not arrange old work merely to please a court where it was already
admired. He never leaves it in a state of mere make-shift, though he cannot
always attain his evident aim of a new originality. His methods of
orchestration and the profoundly significant identity of certain forms of
chorus with certain concerto forms may better be described under their
proper headings (see articles INSTRUMENTATION and CONCERTO). Here we will
attempt first to show, by illustrations of Bach's power of adding parts to
already complete harmonic and contrapuntal schemes, what was his conception
of the nature of an art-form, and secondly, by means of a short analysis of
cases in which he adapts the same music to different words, to define his
range of expression.

Bach arranged all his violin concertos for clavier, including two that are
lost in the original version. Here his power of providing new and
apparently necessary material for the left hand of the cembalist (or, in
the double concertos, two left [v.03 p.0128] hands) without disturbing the
already complete score, is astonishing; and it fails only in the slow
movements, which he prefers to leave obviously in the condition of an
arrangement rather than to spoil their broad cantabile style by a too
polyphonic bass.

But these cases are insignificant compared with such transformations as
that of the prelude of the E major partita for unaccompanied violin into
the sinfonia for organ obligato accompanied by full orchestra (including
three trumpets and a pair of drums) at the beginning of the church cantata,
_Wir danken dir, Gott._ The original version is perhaps the most complete
and natural of the violin solos, for its arpeggios produce full harmony
without recourse to that constant attempt to play on all four strings at
once, which makes the performance of the polyphonic movements a _tour de
force_ in which steady rhythm is nearly impossible. Yet in the sinfonia its
proportions seem to reveal themselves for the first time. Not a bar is
displaced and not a note of the new accompaniment is unnecessary. The whole
is almost entirely without themes; for even this, the lar