The Aeoline is a string stop of very soft tone; the softest string tone in the organ, according to Audsley (but see Echo Aeoline). It is usually found at 8' pitch, but 4' and 16' examples are sometimes found. As a flue stop it first appeared around 1820 in Germany, and soon became popular in Germany, Switzerland and America in both large and small instruments. The names Aeolina, Aeoline and Äoline have also been used for a reed stop; see Aeoline Reed. Irwin gives a different definition for Aeolina Different sources variously describe the Aeoline as belonging to the Gamba, Salicional, or Viol family. The degree of �stringiness� varies between different examples, being more stringy in German examples, according to Maclean. Audsley considers it an Echo Salicional or, if voiced with a more stringy tone, an Echo Viola da Gamba. Bonavia-Hunt and Wedgwood mention Echo Salicional without reference to the Aeoline, but without any description whatsoever. In the absence of further information, we consider them to be synonyms. According to Maclean, Casavant sometimes used the name Dolcissimo for their Aeolines. The Aeoline is often used as one rank of a celeste. Audsley and Locher claim that it is often used with the Voix Celeste, though that stop is usually intended for use with the louder Salicional.
Osiris contains about 100 examples of Aeoline, and eight of Aeolina. All known examples of the other names (as flue stops) are given below. No examples of Echo Viola da Gamba are known. Contributions welcome.