Listed only by Irwin, with the following description: A mild, soft String of 8' manual pitch, sounding like the Viola of regular scale, although this too is a mild and soft stop. . . . It too can form a quiet céleste of mild tone, unique because it is at the same time stringy, soft, and not keen. The Viola Aetheria, is even softer. It is also mentioned in passing by Bonavia-Hunt in his entry for Echo, in which he says: �The most commonly used miniatures are echo flute, echo gamba or viola, echo dulciana (a pianissimo diapason), echo salicional, echo trumpet or tromba, echo mixture.�
Echo Viola 8', Swell; Liverpool Cathedral, Liverpool, England; Willis 1923.