Great (C-a"')						Swell (C-a"')						Choir (C-a"')
16		Open Diapason		58		16		Bourdon		58		8		Geigen Principal		58
8		Open Diapason		58		8		Open Diapason		58		8		Dulciana		58
8		Doppel Flöte		58		8		Viola		58		8		Melodia		58
8		Gamba		58		8		Stopped Diapason		58		8		Rohr Flöte		58
6		Quinte		58		8		Quintadena		58		4		Flute d'Amour		58
4		Flute Harmonique		58		4		Flauto Traverso		58		4		Fugaro		58
4		Octave		58		4		Violino		58		2		Piccolo		58
3		Twelfth		58				Cornet III		174		8		Clarinet		58
2		Fifteenth		58		8		Cornopean		58		8		Vox Angelica		58
		Cornet III		174		8		Oboe		58
		Mixture IV		232		8		Vox Humana		58		Couplers
16		Trumpet		58				Tremolo
8		Trumpet		58								Swell to Great
4		Clarion				Solo (C-a"')						Choir to Great
												Solo to Great
Pedal (C-f')						8		Stentorphon		58		Great Organ Separation
						8		Tuba Mirabilis		58		Swell to Choir
32		Bourdon		30								Choir Sub-Octave
16		Open Diapason		30								Solo Super-Octave
16		Violone		30								Great to Pedal
16		Trombone		30								Swell to Pedal
8		Bell Gamba		30								Choir to Pedal
												Solo to Pedal
BY COUPLING
						Pedal Movements
16		Bourdon		12
12		Quinte				Forte Combination Pedal for Great with appropriate Pedal Stops
8		Violoncello		12		Mezzo Combination Pedal for Great with appropriate Pedal Stops
8		Octave		12		Piano Combination Pedal for Great with appropriate Pedal Stops
8		Trumpet		12		Forte Combination Pedal for Swell with appropriate Pedal Stops
4		Super Octave		12		Piano Combination Pedal for Swell with appropriate Pedal Stops
						Forte Combination Pedal for Choir with appropriate Pedal Stops
						Forte Combination Pedal for Choir with appropriate Pedal Stops
						Full Organ
						Reversible Pedal for Great and Pedal Couplers
						Crescendo Pedal

There are many aspects of this instrument which you should notice from reading this stoplist, many of them going beyond the actual names of the stops involved. But, just thinking about the stops themselves is a good place to start. I have modified a few things in the list, but only by moving a few things around for consistency in the way stoplists are presented in this tutorial. You have surely noticed the unusual pitches associated with the Quinte stops -- 12', 6' and 3' -- and you must have realized that this was merely a "rounding up" of the fractional numbers you are accustomed to. I've left them this way as an example of what you might expect to see on an instrument of this period should you get to play one some day. Don't worry, the sounds will be familiar even though the numbers are unusual by today's standards.

There are some other details which I hope you have noticed as well:

• The overall disposition of stops is derived from English models:
  • The primary manual is the Great, which not only includes more stops than any other division but also is the home of the principal chorus.
  • The Swell is secondary in importance, not only because it has almost as many stops as the Great, but also because it has its own Open Diapason.
  • The Choir division has the smallest number of stops, and no Open Diapason. The 8' Geigen Principal is smaller in scale and tends toward a string tone.
• The full principal chorus on the Great includes the basic components that were traditional in England from the Restoration forward. This chorus consists of the 8' Open Diapason, Octave, Twelfth, Fifteenth, Cornet and Mixture. The names themselves, as well as the inclusion of the Cornet in the hcorus, are English in origin, distinguishing this chorus from similar ones that would be found on German or French instruments. The chorus also includes a 16' Open Diapason, a nineteenth-century addition to both English and American organs.
• Other nineteenth-century innovations include these stops, some of them English in origin, others French or German.
  • Great 8' Doppel Flöte
  • Great 4' Flute Harmonique
  • Swell 8' Cornopean
  • Choir 8' Melodia
  • Choir 8' Vox Angelica
• The Solo division is home to two particularly powerful stops that are associated with wind pressures that were increasing during the late nineteenth century:
  • The Stentorphon is a powerful flue stop, German in origin.
  • The Tuba is a powerful, smooth-toned descendent of Trumpet stops, English in origin.

Some of the other elements that you have probably noticed are related to mechanical matters, so they are discussed below.

Mechanical Charateristics

As you might imagine, an instrument of this size, on high wind pressure and including enough couplers to play four divisions from the Great manual, could present the player with quite a physical challenge. Indeed, playing it would have been very difficult were it not for its inclusion of pneumatic assists -- Barker levers, in other words. According to the brochure, these pneumatic motors were applied to the Great, its couplers, part of the pedal, and to the stops. This last innovation was similar to developments being made by Henry Willis in England, and it allowed several new elements to be included on this instrument.

First of all, I hope you noticed the inclusion of a crescendo pedal. This was new feature on instruments in the nineteenth century, and its appearance on this organ is just one indication of the desire to make it as su-to-date as possible. Similarly, pneumatic motors made it practical to include the very high number of combination pedals found here. The brochure proudly points out that they were double-acting -- reversible, in other words.

Perhaps the most innovative use of pneumatics, however, is found in the list of pedal stops under the unusual heading "BY COUPLING." I've modified the way the brochure listed the number of pipes associated with each stop in the pedal, just so you will notice the way these stops are derived. The process of extending a single rank to provide multiple stops at different pitches was possible before the introduction of pneumatic actions, but it wasn't practical. Here, each rank of the pedal is extended so that it can be played at two pitches, the first one listed, and an octave extension -- described here as available "by coupling." At the keydesk, these extensions were simply available as additional stops, and the form used to describe them here is an indication of how technologically modern the instrument was.

Appearance

As you might expect for such an important instrument, the case and pipe decoration for the Centennial Organ represent the best work that the firm could do at the time. Look at the phograph to the left, made by the Andover Organ Company after the recent rebuild of the instrument.²⁴² You can see the elaborate stencilling, even though the new colors are more muted than the originals. I want you to notice the simple division ofthe "pipe fence" into three sections. Most extended pipe façades of this period used a similar division in order to give a sense of structure to the space. The central pipes are those of the Solo Stentorphon, and they are flanked by pipes of the 16' Open Diapasons. The larger pipes of the 32' Bourdon were originally visible behind the Stentorphon, at the very rear of the organ, but they have since been relocated.