Johann Sebastian Bach - booksnow.scholarsportal.info

APPENDIX. 349On page 30 of Bach's collection of hymns, occurs the hymnsDies sind die heil. 10 Gebot.This hymn is in the Mixolydian mode, that is, G major with F naturalinstead of F sharp. In this mode it is possible to modulate into F,which neither suits the Lydian mode (our F) nor the Ionic (our Cmajor) because their leading notes are only a semitone below the tonicinstead of a whole tone : thus, in C major not B flat, but B is theleading note, and in F major not E flat, but E.From the 25th to the 26th bars he modulates into F major andremains in that key until the 36th bar.Note.—Ordinarily in a major mode, whether Ionic or Lydian,modulation is effected into the key of the fifth above with the greaterthird, as from C major to G major and from F major to C major.In the Mixolydian mode (our G major) modulation cannot be effectedfrom the chief key, G major, to its fifth above, D major, but must gointo D minor, because F in the Mixolydian mode is the proper thirdfrom D.The modulation into D minor takes place in this hymn from bars39 and 40.Note,—As the Mixolydian mode has no semitone below the tonic fora leading note, and consequently no major chord of the dominant, bymeans of which a closing cadence might be made ; it has to closeby going from the chord of the sub-dominant to that of the tonic, asmThe modulation to D minor on page 35 (bars i— 19), in the Mixolydianmode, occurs in other places also, and the close is made by leadingfrom C in the bass part to the tonic G.The hymn, Wir glauben all an einen Gott, on page 37, is in the StrictDoric mode, D minor, in which the major sixth B is essential, and theminor sixth B flat is allowed.On page 39 this hymn is found in the same mode, but transposedinto E; and in order to keep to the mode there is a jfbefore C, so thatjust as B was the major sixth from D, so Cit is the major sixth fromE, notwithstanding that ordinarily F:jf alone is in the signature of thekey of E minor.The chorale which follows this, Vater unser im Himmelreich is also inthe Doric mode transposed to E, and to be known by the Cjt in thesignature.On page 46 is found this same hymn in its proper place in D withoutB flat i.e., with the major sixth B.The hymn on page 47, Christ unser Herr zum Jordan kam, is also inthe Doric mode, but transposed a note lower intoC, as may be seen inthe signature at the beginning. Now ordinarily in C minor there is at? prefixed to B, E, and A ; here, however, A natural is the essential