Friederich Griepenkerl, in his 1844 introduction to Volume 1 of the first complete edition of J. S. Bach's organ works, wrote: -Actually the six Sonatas and the Passacaglia were written for a clavichord with two manuals and pedal, an instrument that, in those days, every beginning organist possessed, which they used beforehand, to practice playing with hands and feet in order to make effective use of them at the organ. It would be a good thing to let such instruments be made again, because actually no one who wants to study to be an organist can really do without one.- What was the role of...