Listed only by Irwin, who says: An undulating 8' Foundation céleste on the manuals, made from two ranks of Gemshorns, sometimes of smaller than normal scale. They may be normal-sharp in pitch design, but are more useful if sharp-flat, since this enables both ranks to sound nearer the normal pitch. A slow undulation offers more uses in combinaion and accompaniment, because it causes less impairment to the timbres of all other pipes. Only the brilliant, small-scale stops are adaptable to fast undulations. The timbre of this céleste can be clear and shining, sounding silvery in some examples. This stop is often a single off-pitch rank, intended for use with a normally pitched Gemshorn.
Numerous examples in