III

In connection with the foregoing it will be interesting to learn the specifications of the principal organs of which Bach was able to avail himself during his long career. We find details concerning them in various works, notably in Adlung (Musica mechanica organoedi), or in the supplement which J.F. Agricola, an esteemed pupil of Bach, added to this work, published after the death of its author; and in the contemporary writings of local historians.

The organ at Arnstadt, the first at which Bach held the position of organist, possessed twenty-four registers, divided among two manuals and the pedal:[179]

Great Organ.

1.Principal,8'
2.Viola da Gamba,8'
3.Quintatön,16'
4.Gedackt (Bourdon),8'
5.Quinte,6'
6.Octave,4'
7.Mixtur, 4 ranks
8.Gemshorn,8'
9.Cymbel, 2 ranks
10.Trompete,8'
11.Tremulant
12.Cymbelstern[180]

Choir Organ.

1. Principal,4'
2. Lieblich Gedackt,8'
3. Spitzflöte,4'
4. Quinte,3'
5. Sesquialter
6. Nachthorn (night horn),4'
7. Mixtur, 2 ranks

Pedal Organ.

1. Principalbass,8'
2. Subbass,16'
3. Posaunenbass (trombone),16'
4. Flötenbass4'
5. Cornetbass,2'[181]

The organ in the palace at Weimar contained the following stops, according to A. Wette:[182]

Great.

1. Principal,8'
2. Quintatön,16'
3. Gemshorn,8'
4. Gedackt,8'
5. Quintatön,4'
6. Octave,4'
7. Mixture, 6 ranks
8. Cymbel, 3 ranks
9. Glockenspiel

Choir.

1. Principal,8'
2. Violdigamba,8'
3. Gedackt,8'
4. Trompete,8'
5. Kleingedackt (small bourdon),4'
6. Octave,4'
7. Waldflöte2'
8. Sesquialtera

Pedal.

1. Gross-Untersatz,32'
2. Subbass,16'
3. Posaun-Bass,16'
4. Violon-Bass,16'
5. Principal-Bass,8'
6. Trompeten-Bass,8'
7. Cornett-Bass,4'

We have mentioned the special feature of the organ in Cöthen: a pedal which boasted of two octaves and a half, from great C to f' sharp; we should further emphasize in this organ, otherwise not especially noteworthy, the quality of the Principal[183] in the great organ, and of the eight-foot Trumpet in the pedal.

The organ in the University church in Leipzig, of which Bach made an expert examination December 17, 1717, was a remarkable instrument, which he was very fond of playing. It was one of the masterworks of the manufacturer Scheibe. It had the following registers:

Great.

1.Gross Principal (of pure tin),16'
2.Gross Quintatön,16'
3.Klein Principal,8'
4.Schalmei,8'
5.Flûte allemande,8'
6.Gemshorn,8'
7.Octave,4'
8.Quinte,3'
9.Quint-Nasat,3'
10.Octavina,2'
11.Waldflöte,2'
12.Grosse Mixtur, of 5 and 6 ranks
13.Cornetti, of 3 ranks
14.Zink (a species of cornett), of 2 ranks

Echo.

1.Principal (in front),8'
2.Viola di Gamba naturelle,8'
3.Grobgedackt (large scale bourdon)8'
4.Octave,4'
5.Rohrflöte,4'
6.Octave,2'
7.Nasat,3'
8.Sedecima,1'
9.Schweizerpfeife,1'
10.Largo.[184]
11.Mixtur, of 3 ranks
12.Helle (bright) Cymbel, of 2 ranks

Choir.

1.Leiblich gedackt,8'
2.Quintatön,8'
3.Flûte douce,4'
4.Quinta decima,4'
5.Decima nona,3'
6.Hohlflöte,2'
7.Viola,2'
8.Vigesima nona,1½'
9.Weitpfeife,1'
10.Mixtur, of 3 ranks
11.Helle Cymbel, of 2 ranks
12.Sertin (serpent?),8'

Pedal.

1.Gross Principal,16'
2.Gross Quintatön,16'
3.Octave,8'
4.Octave,4'
5.Quinte,3'
6.Mixtur, of 5 and 6 ranks
7.Grosse Quintenbass,6'
8.Jubal (open flute),8'
9.Nachthorn,4'
10.Octave,2'
11.Second Principal,16'
12.Subbass,16'
13.Posaune,16'
14.Trompete,8'
15.Hohflöte,1'
16.Mixtur, of 4 ranks

Finally, the specification of the principal organ in the Thomaskirche in Leipzig, installed in 1525, twice rebuilt during the seventeenth century, enlarged in 1670; and considerably repaired, in 1721, by Johann Scheibe:[185]

Great.

1. Principal,16'
2. Principal,8'
3. Quintatön,16'
4. Octave,4'
5. Quinte,3'
6. Superoctave,2'
7. Spielpfeife (a species of flute),8'
8. Sesquialtera
9. Mixtur, of 6, 8, and 10 ranks

Echo (Brustwerk).

1. Grobgedackt,8'
2. Principal,4'
3. Nachthorn,4'
4. Nasat,3'
5. Gemshorn,2'
6. Cymbel, of 2 ranks
7. Sesquialtera
8. Regal,8'
9. Geigenregal[186] (Violin-regal),4'

Choir.

1.Principal8'
2.Quintatön,8'
3.Lieblich Gedackt,8'
4.Kleingedackt,4'
5.Querflöte (Flauto traverso),4'
6.Violine,2'
7.Rauschquinte doppelt
8.Mixtur, of 4 ranks
9.Sesquialtera
10.Spitzflöte,4'
11.Schallflöte,1'
12.Krummhorn,[187]16'
13.Trompete,8'

Pedal.

1. Subbass (of metal),16'
2. Posaune,16'
3. Trompete,8'
4. Schalmei,4'
5. Cornett,3'

The St. Thomas church possessed in addition a small organ. This instrument, at one time abandoned, and later again brought into service, stood at Bach's time in a gallery, opposite the large organ. It possessed a stop called Trichter-Regal, a sort of Vox humana. This organ was used in performance of the St. Matthew Passion music, in coöperation with the other.

When Bach played for strangers, he was fond of astonishing them by his originality in registration. "After having first of all censured as ill-advised the combination of certain stops," says Forkel,[188] "the listeners were greatly surprised upon hearing the admirable effect produced by these very combinations, suddenly drawing from the organ a sonority at once original and varied, whose attainment might have been vainly sought by following older methods....

"In trying an unfamiliar organ, his first step was to draw all the registers and to play upon the great manual with all couplers. He was in the habit of saying, jestingly, that he wished at the outset to know if the instrument possessed good lungs."

With this art in registration was combined the greatest facility in improvisation.

"It was often the case," writes Kirnberger,[189] "that friends asked Bach to play to them at times other than during religious service. Then he would choose some theme and treat it in every form of organ composition, playing without interruption for two hours or more, yet without exhausting his resources. Perhaps he made use of his subject first in a prelude and fugue for all the foundation stops. Then his genius in registration was displayed in a movement in three, or in four, parts, always upon the same theme. Now followed a chorale, and the subject served as a counterpoint to the chorale-melody, in ingenious imitations in three or four voices. Finally he concluded by a fugue for organo pleno, based upon the same subject, interweaving the previous variations of it he had made."