This rare open flute stop of 8' or 4' pitch is made of wood or, according to Grove and Williams, metal. In some examples (the finer ones, according to Audsley and Sumner, who specify a medium scale), the pipes are of inverted pyramidal form, giving the tone a slight stringiness or reediness. The name is probably a corruption of Bourdon. Grove and Williams date this stop from the 17th century. Maclean lists Portunal and Portunalflöte with the following description:

It was a speciality of the reputable nineteenth century firm of Schlag & Sons, who introduced it into their organ at the Philharmonic Hall, Berlin. The tone was said to have had a veiled and velvety sound, with a suggestion of Clarinet quality in the lower part of its compass.

Examples

Osiris contains six examples of Bordunalflöte at 8' pitch, two examples of Portunalflöte at 8' pitch and one at 4', one example of Portunal at each of 16', 8' and 4', and one example of Portunal Flute. The oldest examples are given below. No examples are known of Bourdonalflöte, which is mentioned only by Audsley in The Art of Organ Building, and may have been a figment of his imagination, or of Portunen, mentioned only by Williams.

Bordunalflöte 8', 2nd Manual; Cathedral of Schwerin; Ladegast 1871.

Bordunalflöte 8', Manual I; Johanniskirche, Wernigerode, Germany; Ladegast 1885 (restored 1989-91).

Bordunalflöte 8', 2nd Manual; Nicolaikirche, Leipzig, Germany; Ladegast.

Portunal 16', Grand Orgue; St. Louis, Vichy, France; Aubertin 1990's?.

Portunal 8', 4', Hauptwerk; Dreifaltigkeitskirche (Holy Trinity Church), Lipaja/Libau, Latvia; Grüneberg 1885.

Portunalflöte 4', Schwellwerk; Luitpoldhalle, Nürnberg, Germany; Walcker 1936 (destroyed).

Portunal Flute 2', Great; Caldwell Chapel, Louisville Presbyterian Theological Seminary, Lousiville, Kentucky, USA; Steiner 1985.

Bibliography