This stop is listed only by Irwin, who says:

A large-scale Diapason of prominent tone, falling into one of the following classifications:

• the chief Diapason 8' on any manual;
• the chief Octave 4' on any manual;
• the chief Diapason 16' on the pedals.

Occasionally the 16' rank is made from wood.

Audsley mentions the name only in passing, without any definition.

Examples

Osiris contains only one example:

Major Principal 8', Great; Church of St Batholomew, Armley, England; Schulze 1866-69.

Bibliography