A man may possess all these qualities, however, and remain an indifferent performer on the Clavier, just as clear and agreeable enunciation does not necessarily make a good speaker. To be a first-rate performer many other qualities are needed, and Bach possessed them all in a notable degree. Some fingers are longer and stronger than others. Hence players are frequently seduced to use the stronger whenever they can readily do so. Consequently successive notes become unequal in tone, and passages which leave no choice as to the finger to be used may become impossible to play. Bach recognised this fact very early in his career. To get over the difficulty he invented exercises for his own use in which the fingers of both hands were made to practise passages in every conceivable position. By this means every finger on both hands equally became strong and serviceable, so that he could play a rapid succession of chords, single and double “shakes,” and running passages with the utmost finish and delicacy, and was equally fluent in passages where some fingers play a “shake” while the others on the same hand continue the melody. Besides these improvements, Bach invented a new system of fingering.(122) Before his time, and even in his early years, it was usual for the player to pay attention to harmony rather than counterpoint. Even so it was not customary to use every one of the twenty-four major and minor keys. The Clavichord was still what we term “gebunden”; that is, several keys struck the same string, which, therefore, could not be accurately tuned.(123) Consequently it was usual to employ only those keys whose notes were tuned with some approximation to accuracy. Again, good players in those days hardly ever used the thumb, except when a large interval had to be stretched. But when Bach began to melodise harmony so that his middle parts not merely filled in but had a tune of their own, when, too, he began to deviate from the Church modes then in general vogue in secular music, using the diatonic and chromatic scales indifferently, and tuning the Clavier in all the twenty-four keys, he found himself compelled to introduce a system of fingering better adapted to his innovations than that in use, and in particular, to challenge the convention which condemned the thumb to inactivity. It is held by some writers that Couperin forestalled Bach’s method of fingering, in his _L’Art de toucher le Clavecin,_ published in 1716. But that is not the case. In the first place, Bach was above thirty years old in 1716, and had already developed a distinctive method of his own. And in the second place, Couperin’s system differs materially from Bach’s, though both made more frequent use of the thumb than was so far customary. When I say “more frequent use” I do so advisedly; for whereas in Bach’s system the thumb is the principal finger—for the difficult keys, as they are called, are unplayable without