From about the year 1720, when he was thirty-five, until his death in 1750, Bach's harmony consists in this melodic interweaving of independent melodies, so perfect in their union that each part seems to constitute the true melody. Herein Bach excels all the composers in the world.[143] At least, I have found no one to equal him in music known to me. Even in his four-part writing we can, not infrequently, leave out the upper and lower parts and still find the middle parts melodious and agreeable.
But in harmony of this kind each part must be highly plastic; otherwise it cannot play its role as an actual melody and at the same time combine with the other parts. To produce it Bach followed a course of his own, upon which the textbooks of his day were silent, but which his genius suggested to him. Its originality consists in the freedom of his part writing, in which he transgresses, seemingly, at any rate, rules long established and to his contemporaries almost sacred. Bach, however, realised their object, which was simply to facilitate the flow of pure melody on a sound harmonic basis, in other words, successive and coexistent euphony, and he succeeded with singular success though by [pg 75] unfamiliar means. Let me explain my meaning more closely.
Between simple intervals there is little difficulty in deciding whether the second note must rise or fall. And in regard to phrases, or sections of a phrase, if we analyse their structure and follow out their harmonic tendency, their resolution is equally clear. But this sense of destination may be provoked in each part by different intervals. As we have observed already, every one of the four parts must flow melodically and freely. But to secure that result it will be necessary to introduce between the notes which begin a phrase and establish its general atmosphere other notes which often are not consonant with those employed in the other parts and whose incidence is governed by the accent. This is what we call a transitus regularis et irregularis.[144] Each part starts from a fixed point, and returns to it, but travels freely between them. No one has made more use of such progressions than Bach in order to colour his parts and give them a characteristic melodic line. Hence, unless his music is played with perfect fluency, occasional passages will sound harshly and we may be tempted to accuse him of exaggeration. But the charge is ill founded. Once we play them as Bach intended [pg 76 ] them, such passages reveal their full beauty and their attractive though bizarre dissonance opens up new vistas in the realm of sound.
But, to speak in detail of Bach's transgression of recognised rules. To begin with, he admitted octaves and fifths provided they sounded well; that is, when the cause of their being forbidden did not arise.[145] Everybody knows that there are positions in which they sound well, and others when they should be avoided, owing to the harsh effect or thin harmony they produce. Bach's octaves and fifths never produce bad or thin harmony, and he was very definite as to when they could and could not be used. In certain circumstances he would not permit hidden fifths and octaves even between the middle parts, though we exclude them only between the outer parts. Yet, on occasion he used them in such a barefaced manner as to puzzle the beginner in composition. But their use very soon commends itself. Even in the last revision of his early compositions we find him altering passages, which at first sight appear impeccable, with the object of enriching their harmony and without scrupling to use hidden octaves. A remarkable instance occurs [pg 77] in the first part of the Well-tempered Clavier, in the E major Fugue, between the fifth and fourth bars from the end.[146] I regret to this hour that, on looking over the later text, from which Hoffmeister and Kühnel's edition of that work is printed,[147] I was so foolish as to reject Bach's amended reading there, merely because the harmony is unorthodox though more pleasing. I stupidly preferred the older, more correct, and harsher reading, though in the later text the three parts run easily and smoothly. And what more can one demand?
Again, there is a rule that every note raised by an accidental cannot be doubled in the chord, because the raised note must, from its nature, resolve on the note above. If it is doubled, it must rise doubled in both parts and, consequently, form consecutive octaves. Such is the rule. But Bach frequently doubles not only notes accidentally raised elsewhere in the scale but actually the semitonium modi or leading-note itself. Yet he avoids consecutive octaves. His finest works yield examples of this.
Again, Bach's statement that “over a pedal point all intervals are permissible that occur in the three scales”[148] should be regarded rather [pg 78] an expansion than a violation of the recognised rule. In general what is called an Organ point is merely a retarded close. Bach, however, did not hesitate to employ it in the middle of a piece; a striking example occurs in the last Gigue of the English Suites.[149] On a first hearing this Gigue, imperfectly rendered, may not sound well. But it grows more beautiful as it becomes more familiar, and what seemed harsh is found to be smooth and agreeable, until one never tires of playing and hearing it.
Bach's modulation was as original and characteristic as his harmony, and as closely related to it. But the two things, though closely associated, are not the same. By harmony we mean the concordance of several parts; by modulation, their progression through keys. Modulation can take place in a single part. Harmony requires more than one. I will endeavour to make my meaning clearer.
Most composers stick closely to their tonic key and modulate out of it with deliberation. In music that requires a large number of performers, and in a building, for instance a church, where the large volume of sound dies away slowly, such a habit shows good sense in the composer who wishes his work to produce the best possible effect. But in chamber or instrumental music it is not always a proof of wisdom, but rather of mental poverty. Bach saw clearly that the two [pg 79] styles demand different treatment. In his large choral compositions he bridles his exuberant fancy. In his instrumental works he lets himself go. As he never courted popularity, but always pursued his ideal, Bach had no reason to suppress the nobility of his inspirations, or to lower their standard for public consumption. Nor did he ever do so. Therefore every modulation in his instrumental work is a new thought, a constantly progressive creation in the plane of the chosen keys and those related to them. He holds fast to the essentials of harmony, but with every modulation introduces a new suggestion and glides so smoothly to the end of a piece that no creaking of machinery is perceptible; yet no single bar—I might almost say no part of a bar—is like another. Every modulation bears a strict relationship to the key from which it proceeds, and springs naturally from it. Bach ignored, or rather despised, the sudden sallies by which many composers seek to surprise their hearers. Even in his chromatic passages his progressions are so smooth and easy that we are hardly conscious of them, however extreme they may be. He makes us feel that he has not stepped outside the diatonic scale, so quick is he to seize upon the consonances common to dissonant systems and combine them to his sure purpose.
The Bach Statue at Eisenach