Here there is in the subject a distinct modulation to D; the answer therefore modulates back to G. B, the second note of the subject, could have been answered either by F sharp or E; but had Mozart answered it by F sharp, the resemblance of answer to subject would have been spoilt—
There would, besides, have been another fault of almost more importance. The subject has a distinct modulation to the dominant; the last three notes unquestionably suggest the key of D. The answer therefore should as clearly suggest G; but in its altered form it does not do so at all, as the first four notes all belong to the tonic chord of D. Neither shall we improve matters by putting B for the third note of the answer instead of A; for then the answer will not distinctly suggest any key at all, the first three notes now being notes of the tonic chord of B minor. There is, therefore, no other correct answer than that which Mozart gives, and, having reached the dominant key at the second note, he regards all the rest of the subject as being in that key, and accordingly treats E as supertonic of D—not as submediant of G—and answers it by A, and not by B. The last two notes of the subject, of course, admit of only one answer.
125. After our full analysis of this example, few words will be needed in explanation of the following, which illustrate the same point—
Handel. 'Israel in Egypt.
J. S. Bach. Matthäus Passion.
At (a) the C in the subject is regarded as sixth of E minor, and answered by F; and at (b) G sharp is considered not as the leading note of A minor, but as the chromatic major third of the dominant, and it is accordingly answered by the major third of the tonic.
126. The reason why the tonal change is made as early as possible is because in this way a closer general resemblance of the
