IV
About the time Friedemann, his first born son, was nine years old Bach began to compose for him the book of pieces known as the ‘Little Clavier Book.’ It is what we should call to-day a graded collection of short pieces intended to perfect the already striking abilities of his son. Beginning with the simplest elements, he introduced difficulties by degrees until the last pieces, in polyphonic style, demand a very considerable skill. The most interesting passages are those in which Bach has indicated the fingering, for they prove that he reorganized all the systems of fingering in use in his day and perfected one of his own upon which future developments are based. His chief innovation is in the manner of using the thumb. Up to the time of Couperin, players of keyed instruments used only the four fingers of the hand. The thumb hung idle. The position must have been stiff and awkward and it is hard to understand how such brilliant performers as the north German organists ever overcame the difficulties of it. Yet Bach himself told his son Emanuel that in his youth he had seen great organists play who never used the thumb except for the widest stretches. Couperin’s famous book on the art of playing the harpsichord appeared in 1717, the very year Bach went to Cöthen. In it he advocated the use of the thumb, but over the fingers, not under them. Bach was one of the first to appreciate the advantages of passing the thumb under the hand. It is hardly possible that he invented the practice. Many of the oldest works for the harpsichord must have called for a use of the thumb, and the contemporary works of Domenico Scarlatti would have been almost insurmountably difficult without it; but in theory the use of the thumb under the hand was avoided, and Bach’s ‘Little Clavier Book’ contains probably the first open recognition of the advantages of so using it, no matter what the actual practice of virtuosi had been up to that time. One will observe that Bach did not abandon the old system, and that many passages marked by him are to be played in the old way; that is, by passing the long fingers, chiefly the middle finger, over the short ones; but he laid the foundations of the new. The most famous of players in the next generation was his own son Emanuel, whose book on playing the harpsichord was the standard authority down to the time that the harpsichord was finally supplanted by the pianoforte. Haydn and Mozart undoubtedly profited by it, and thus the methods of the father were spread abroad through the son and played a considerable part in the development of music for the pianoforte.
‘The Well-tempered Clavichord’[158] is unquestionably an epoch-making work. It is, as is well known, a series of preludes and fugues in all major and minor keys. The term ‘well-tempered’ refers to Bach’s method of tuning the clavichord, which for the first time made such an unbounded use of harmony possible. It will be remembered that the first keyboards had only those keys which are to-day white, sounding only the diatonic tones of the modes. The first chromatic alteration allowed in these modes was the B-flat, which was practically forced upon musicians in order to avoid the augmented interval between F and B natural, an interval excruciating to their ears. So the black key between A and B was the first to find its place on the keyboard, and it was tuned in the relation of a perfect fourth with the F below. E-flat seems to have been the next black key and was tuned in the relation of a perfect fourth to the B-flat. The other black keys were added one by one, nearly always in exact relation to some one of the white keys or the original diatonic notes of the modes, F sharp in that of a perfect fifth with the B below, G sharp in that of a perfect major third with E, C sharp in the same relation with A. Inasmuch as all these intervals were mathematically exact—and such was the idea of tuning all through the Middle Ages and nearly to the time of Bach—the black keys were in perfect relation only with one or more of the white keys, and often quite out of relation with each other. The intervals between them were very noticeably out of tune and false. When, during the seventeenth century, our harmonic system of transposing keys finally supplanted the old modal system, composers for the harpsichord and the organ still found themselves limited by their keyboards to three sharp keys and two flat, so long as their instruments were perfectly tuned.
A cursory glance at some of the old harpsichord music shows that composers did not by any means submit to such a restriction, and we must presume that, unless they were willing to endure the sound of many hideous imperfections, they developed in practice at any rate some system of tuning which softened or tempered them. Bach, therefore, is not the inventor of the first tempered tuning, but it is doubtful if any composer before him had worked out such a satisfactory system as his which has been called equal temperament, and which amounts practically to the division of the keyboard octave into twelve equal though slightly imperfect intervals. Only the octave remained strictly in tune. The imperfections of the other intervals were so slight, however, as to be hardly perceptible. Thus the black keys of the keyboard came to represent two notes, different in theory, the sharp of the note below and the flat of the note above; and, by such a compromise, composers for the instrument were enabled to modulate freely through all keys. Bach must be acknowledged the first great musician to recognize the inestimable value of such a liberation, in proof of which he wrote the first series of the ‘Well-tempered Clavichord.’ The fugues notably are enriched by the most beautiful modulations, and in this regard the collection may be said to be almost the foundation upon which all subsequent music has been built, and to contain the seeds from which the most soaring harmonies of Beethoven, Chopin and even Wagner have sprung. Thus we are brought back by the ‘Well-tempered Clavichord’ to the crowning glory of his genius, his gift for harmony. Beethoven knew the Well-tempered Clavichord.’ He is said to have won his first distinction as a pianist by his playing of those preludes and fugues in Vienna. And Beethoven called Bach the forefather of harmony.
Probably no collection of pieces has been so carefully studied and sounded again and again by generation after generation of composers and probably no other set of pieces will ever prove so impervious to every influence of time. It is like an eternal spring, forever fresh, forever marvellous. Scarcely less wonderful are the collections of two- and three-part Inventions. Both these and the preludes and fugues were written as exercises—the one, in Bach’s own words, as ‘an honest guide by which the lovers of the clavier, but particularly those who desire to learn, are shown a plain way not only to play neatly in two parts, but also, in further progress, to play correctly and well in three obbligato parts; and, at the same time, not only to acquire good ideas, but also to work them out themselves; and, finally, to acquire a cantabile style of playing, and, at the same time, to gain a strong predilection for, and foretaste of, composition’; the other ‘for the use and practice of young musicians who desire to learn, as for those who are already skilled in this study, for amusement.’ There can be no better testimony to Bach as a teacher than these short prefaces, written in his own fine hand, upon the title pages of the two sets. For him, the greatest virtuoso of his day, virtuosity was nothing, and he taught those about him above all to seek to express only what was genuine and fine in music. So he continues to teach the world of musicians, though music has passed through fire and tempest since he wrote these pieces all but two hundred years ago in the castle at Cöthen. Styles have changed, forms have changed, instruments have changed; the state, the world, are no longer the same; yet in every state and to every corner of the world where there are men and women who have devoted their lives to music, there will Bach be found as the touchstone of all that is good in the art.