Again, there is a rule that every note raised by an accidental cannot be doubled in the chord, because the raised note must, from its nature, resolve on the note above. If it is doubled, it must rise doubled in both parts and, consequently, form consecutive octaves. Such is the rule. But Bach frequently doubles not only notes accidentally raised elsewhere in the scale but actually the semitonium modi or leading-note itself. Yet he avoids consecutive octaves. His finest works yield examples of this. Again, Bach’s statement that “over a pedal point all intervals are permissible that occur in the three scales”(148) should be regarded rather an expansion than a violation of the recognised rule. In general what is called an Organ point is merely a retarded close. Bach, however, did not hesitate to employ it in the middle of a piece; a striking example occurs in the last Gigue of the _English Suites._(149) On a first hearing this Gigue, imperfectly rendered, may not sound well. But it grows more beautiful as it becomes more familiar, and what seemed harsh is found to be smooth and agreeable, until one never tires of playing and hearing it. Bach’s modulation was as original and characteristic as his harmony, and as closely related to it. But the two things, though closely associated, are not the same. By harmony we mean the concordance of several parts; by modulation, their progression through keys. Modulation can take place in a single part. Harmony requires more than one. I will endeavour to make my meaning clearer.