What has been said regarding Bach’s admirable Clavier playing applies generally to his skill as an organist. The Clavier and Organ have points in common, but in style and touch are as different as their respective uses. What sounds well on the Clavier is ineffective on the Organ, and vice versa. The most accomplished Clavier player may be, and usually is, a bad organist unless he realises the differing natures of the two instruments and the uses they serve. I have come across only two men who can be regarded as exceptions to this general rule—Bach and his eldest son, Wilhelm Friedemann. Both were finished Clavier performers, but no trace of the Clavier style was apparent when they played the Organ. Melody, harmony, and pace were carefully selected with due regard to the nature and distinctive use of each instrument. When Wilhelm Friedemann played the Clavier his touch was elegant, delicate, agreeable. When he played the Organ he inspired a feeling of reverent awe. On the one he was charming. On the other he was solemn, impressive. So also was his father, and to an even greater degree. Wilhelm Friedemann was a mere child to him as an organist, and frankly admitted the fact.(131) The music that extraordinary man wrote for the Organ is full of dignity, awe-inspiring, saturated with the atmosphere of devotion. His improvisation was even more inspired, dignified, and impressive: for then his imagination was untrammelled by the irksomeness of expressing himself on paper. What is the essence of this art? Let me, though imperfectly, attempt an answer. When we compare Bach’s Clavier compositions with those written for the Organ it is at once apparent that they differ essentially in melodic and harmonic structure. Hence we conclude that a good organist must select fitting themes for his instrument, and let himself be guided by its character and that of the place in which it stands and by the objects of its use. Its great body of tone renders the Organ ill-adapted to light and jaunty music. Its echoes must have liberty to rise and fall in the dim spaces of the church, otherwise the sound becomes confused, blurred, and unintelligible. What is played upon it must be suited to the place and the instrument, in other words, must be congruous to a solemn and majestic fabric. Occasionally and exceptionally a solo stop may be used in a Trio, etc. But the proper function of the Organ is to support church singing and to stimulate devotional feeling. The composer therefore must not write music for it which is congruous to secular surroundings. What is commonplace and trite can neither impress the hearer nor excite devotional feeling. It must therefore be banished from the Organ-loft. How clearly Bach grasped that fact! Even his secular music disdained trivialities. Much more so his Organ music, in which he seems to soar as a spirit above this mortal planet.