ts quota of pipes and designated as follows:
1. The Great organ, consisting of the front pipes and other loud-speaking stops. Back of this and usually elevated above the level of the Great organ pipes is
2. The Swell organ, all the pipes of which are contained in a wooden box with Venetian shutters in front, the opening or closing of which modifies the tone; below the Swell box is placed
3. The Choir organ, containing soft speaking pipes suitable for accompanying the human voice; and back of all or on the sides is
4. The Pedal organ, containing the large pipes played by the pedals.
Larger instruments have still another wind-chest called the Solo organ, the pipes of which are very loud and are usually placed high above the Great organ.
In some large English organs, notably that in the Town Hall of Leeds, a further division was effected, the pipes of the Great organ being placed on two wind-chests, one behind the other. They were known as Front Great and Back Great.