There is no advance in these fingerings on the book by Ammerbach, published in 1571.

The right thumb it will be seen was unused, and hung helpless—the fingers being stretched out flat to reach the keys.

In order to bring the thumb into use, Bach caused the fingers to be curved and to remain over their respective keys, so as to be able to strike them accurately and rapidly. The thumbs had to pass under the fingers, and to take an equal part with them in the playing.

The new kind of fingering was made the more necessary by the use of all the keys equally; for hitherto only a few keys had been used. The hand and arm were to be held horizontally, the wrist straight; the fingers bent in the natural position assumed by the hand when about to grasp any object. Each finger had to fall without disturbing the others; and Bach devoted an immense amount of labour to make his fingers independent and equal in strength. He could perform trills with all fingers equally well, and could play melodies at the same time with the other fingers. After a finger had held down a note as long as was necessary it was drawn towards the inner part of the hand on leaving the key. The wrist and elbows were kept perfectly quiet. The method was the same for both organ and harpsichord. The keys were not struck but pressed down. Bach raised his fingers so little that their movement was hardly noticeable. They were, however, still passed over one another, as well as the thumb, and in order not to break the legato effect, the finger passed over was drawn back before leaving the key. This method was particularly applicable to the clavichord, one of Bach’s favourite instruments.

He liked the upper row of keys to be shallower than the lower, so that he could slip down from one to the other without change of finger.

But others were at work on the same ground. Couperin, organist of St Gervais at Paris, published in 1717 his “L’art de toucher le clavecin.” J. G. Walther used the thumb, and has left some organ chorales with this indicated.

Heinichen and Handel also used the thumbs, and bent their fingers over the notes, so that they struck the right ones unconsciously.

Two short pieces with Bach’s fingering in his own hand have come down to us—the rules laid down by his son C. P. Emanuel differ from them considerably—thus Emanuel limits the crossing to the thumb; Sebastian prescribes crossing of fingers as well.

Sebastian, in fact, retained all that was advantageous in the old system and engrafted on it the use of the thumb, etc. His son, who was the forerunner of modern piano-playing, simplifies his father’s rules. His compositions were of a far less complicated nature than those of his father, and he therefore was able to use simpler fingering.

The hammer-like stroke required for the modern piano effectually banished the crossing of fingers over one another, by which pressure only, not a blow, could be obtained. The loss of Bach’s complete method of fingering (which is not adapted for the piano) causes his compositions to be more difficult to the modern player than they were to him, but this does not hold good of the organ, the nature of which remains the same as in his time.

He played equally in all keys, and for this purpose had his instruments tuned in equal temperament, as is universally the case at present. Experiments had been made in this method of tuning by Werkmeister, who died in 1706, and, later, by J. G. Neidhardt.

The early experiments in tempering must have led to curious results—thus the major-thirds were flattened; and yet only when three major-thirds are sharpened (CE, E G?, G? (A?) C) do they reach a purely tuned octave. Bach mastered the problem for himself. He tuned his own harpsichord and clavichord, making the major-thirds rather sharp; and he must have flattened the fifths as we do. His son Emanuel speaks of his testing the fifths by tuning their octave below, and making this a fourth below the starting point. What he did was the result of practical experiment, for he would have nothing to do with mathematical theory. He always quilled his harpsichord himself; and he made a point of practising the clavichord, since the expression possible on this instrument made the ear keener and more sensitive to the possibility of effect on the more inexpressive harpsichord.

Spitta considers that Bach’s genius in a way foresaw the advent of a more perfect instrument than either the clavichord or harpsichord—an instrument which should combine the expression of the first with the power of the latter, and at the same time approach the organ in possibilities of legato and sustained sounds. Such an instrument is the modern pianoforte.

In 1740 Bach planned a lute-harpsichord, and got Zacharias Hildebrand, an organ-builder, to make it under his direction. It had gut strings, two to each key, and a set of octave metal strings. It had also cloth dampers, which made the instrument sound something like a real lute; and when these were raised, it sounded like a theorbo—it was in size shorter than an ordinary harpsichord (Adlung Mus. Mech. II., p. 139).

Although Bach was concertmeister, or leader of the orchestra at CÖthen, it is not to be supposed that he had any extraordinary facility on the violin. Quantz, in “Versuch einer Anweisung, etc.,” rightly considers that for such a post, at any rate in those days, it was more necessary that the holder should be a good all-round musician with sufficient facility to execute the ordinary orchestral music, than that he should be a “virtuoso”—and not every virtuoso makes a good leader.

It seems impossible that he could have himself performed his violin and violoncello sonatas; they tax the highest efforts of the best performers of the present day; but his knowledge of stringed instruments and their possibilities is shown by these compositions to have been as profound as his knowledge of the organ. No mere theoretical knowledge could have sufficed to enable him to write these things; he must have had a wider practical knowledge than any but the best virtuosi, and to this he united his enormous genius for composition.

It appears natural that the German violinists, with their feeling for full harmony, should have cultivated the art of double-stopping on stringed instruments, rather than that of pure melody and tone. It is said that Bruhns the organist, Buxtehude’s pupil, while playing in three and four parts on his violin, would sometimes sit before an organ, and add a bass on the pedals.[79]