In current organ usage, strongly influenced by German terminology, a positive is (1) a movable organ as distinct from a Portative or portable organ, and (2) that manual of a larger organ that resembles (and perhaps historically originated in) such a smaller organ. The English Chamber organ is a positive; so are the tall, shallow gothic instruments of two to three octaves (often beginning at B) and one to three ranks of flue pipes sometimes accompanied by Bourdons in the bass, frequently represented in the 15th century as being played by one angel and blown by another (altar paintings of Van Eyck, Van der Goes). Henri Arnaut de Zwolle (MS, c1450) distinguished carefully between the small portivus, the larger organum or opus (cf Werk) and the positivo, especially the positivo tergali or Rückpositiv; the distinction was kept by Virdung (1511) and his plagiarizers. In England the term does not seem to have been used, while Schlick (1511) applied it to any small chest within a larger organ, such as the positive zu Rück or that forn an die Brust – as did some builders of the time (Van der Distelen at Antwerp Cathedral, 1505). In France, le positif usually means the Chair organ in any source after c1520; previous to that it is unknown how many of the petites orgues were Chair organs or independent positive organs. Only from other sources is it clear that the Posityff at Zwolle (1447) and the positif de la grande at Angers (1513) were Chair organs. Later independent positives vary immensely, some with more than one manual, some with pedal stops, some blown by the player with a foot lever, some placed (Lat. ponere, positum) on tables, others too large to be easily movable, but most based on a Principal rank smaller than 8'.
For further illustrations see Hofhaimer, Paul and Organ, figs.30 and 33.
H. Bornefeld: Das Positiv (Kassel, 1946)
J. Perrot: L'orgue de ses origines hellénistiques à la fin du XIIIe siècle (Paris, 1965; Eng. trans., 1971)
P. Hardouin: ‘Twelve Well-Known Positive Organs: Useful Evidence or Difficult Problems?’, Organ Yearbook, v (1974), 20–29
E.A. Bowles: ‘Preliminary Checklist of Fifteenth-Century Representations of Organs in Paintings and Manuscript Illuminations’, Organ Yearbook, xii (1982), 5–30
K. Marshall: Icongraphical Evidence for the Late-Medieval Organ in French, Flemish and English Manuscripts (New York, 1989)
P.F. Williams: The Organ in Western Culture, 750–1250 (Cambridge, 1993)
PETER WILLIAMS, NICHOLAS THISTLETHWAITE