Handel, however, furnishes a very striking illustration--

In the six "Sonatas or Trios for two Hoboys with a thorough bass for
the harpsichord," said to have been composed already in 1696, we find
quick movements in binary form. In some, the first section offers both
a first and a second subject, while in the second section, after
modulation, there is a return to the opening theme, though quite at
the close of that section. A brief description of one will make the
form clearer. The second Allegro of No. 4 (in F) has two sections. The
first, which ends in the dominant key (C), contains forty-six bars.
The opening theme begins thus:--

[Music illustration: _a_]

At the twenty-ninth bar, a passage leads to the second theme--

[Music illustration: _b_]

This second theme is, in a measure, evolved from the first. In any
case, it is of subordinate character; and it differs slightly as given
by first or second oboe, whereas the principal theme appears in
exactly the same manner for both instruments.

The second section opens with developments of _b_, and modulation from
C major to D minor; _a_ also is developed, the music passing from the
last-named key back to the opening one. There is a full close in that
key, and then modulation to F. The remaining twenty-two bars give the
first section in condensed form: first and second subjects and
coda.[10]