We know how Bach brought out the significance of these chorales, interpreted with such supereminence, by the deft combination of the parts. The execution of a design did not make him oblivious of the interest attached to the coloring. We have already spoken of the chorale _In dir ist Freude_; who knows whether Bach did not intend still further to accentuate its joyous character by picturesque registration? Adlung speaks of the _carillon_ (_Glockenspiel_) as being particularly fitted to symbolize gladness; and says that use was made of it only at the most joyous festivals. Mark the spiritedness of this chorale; and, further, the repetition of the _chaconne_ subject presented in the bass, singularly suggestive of a chime of bells; and consider the period to which this composition belongs, bearing in its form the distinct impress of the organists of the North. Without serious error, could we not ascribe it to the years 1708 or 1709, the time when Bach, occupied with the restoration of the organ in Mühlhausen, wished to add, in the pedal, a _carillon_ of his own invention? Would not the contrast of those metallic tones of four-foot pitch[161] with the deep resonance of the _Untersatz_ of thirty-two, which he also demanded, have produced all the harmonic overtones of real bells?... But this is only an hypothesis, though a plausible one, and one which it would be amusing to justify by trying its effect in actual performance. [Footnote 161: It appears that this _carillon_ was not constructed; it is possible, however, that Bach had it in mind when writing the chorale. Moreover, it was to be found in other organs.]