The name Nachthorn has been used over the centuries for at least three different stops: According to Grove and Williams, in the 1500's it was frequently a type of Cornet mixture, especially in the Netherlands and northern France. One common form is a stopped flute of very wide scale, a cross between a Quintaten and a Gedeckt, having a tone that some sources describe as somewhat horn-like. It was found at 4' and 2' pitch, and made of wood or metal. Wedgwood gives it a low cut-up. Grove and Williams date this form from the time of Praetorius (around 1600), and Williams puts it also in 18th century Austria. Skinner used this form, describing its tone as being suggestive of a hoot-owl. A synonym for this form may be Nachthorngedackt. The other common form is an open flute of very wide scale, wider than any other stop according to Williams and Maclean. It generally has a low, narrow mouth, which gives it a soft voice in spite of its large scale. Grove and Williams date this form from the 17th century, where it was used as a solo stop in either manual and pedal. This seems to be the most common contemporary form of the stop. Other forms have also been cited: a large-scale Rohrflöte with small chimneys (Williams), slightly conical (Irwin), and a reed (Wedgwood). Irwin claims that it is sometimes tuned as a slow celeste (see Cor de Nuit Celeste), and that it is sometimes found at 5-1/3' and 2-2/3' pitch, though no mutation examples are known. While most sources translate Nachthorn as �night horn�, Williams suggests that the name may derive from Nach-horn or Nachsatz (nach = �behind�), a stop taken from the Hintersatz (blockwerk). Most sources consider Cor de Nuit and Nachthorn to be synonymous, but some make a distinction; see Cor de Nuit.
Osiris contains well over 300 examples of Nachthorn, most at 4' or 2' pitch, some at 8' or 1' pitch, and a handful at 16' from German organs of the early 20th century. Of Nachthoorn there are twenty examples: two at 8' (both 20th century), nine at 4', seventeen at 2', and two at 1'. There are eight examples of Night Horn at 4', five examples at 2', and one at 8'. Osiris contains one example each of Nachthornbass and Nachtschall. No examples of Nachthornchen are known. Contributions welcome.