A soft and delicately toned mixture, made from small-scaled string or Dulciana ranks. According to Audsley, German builders did not put breaks in its ranks, which number two or more. Wedgwood considers it to be virtually identical to the Echo Cornet or Dulciana Cornet.
Osiris contains eight examples of Harmonia Aetherea, eleven examples of Harmonia Aethera, two of Harmonica Aetheria, and none of Harmonica Aetherica. It is not known how many of these may be misspellings. All are III or IV (or III-IV) ranks, except for a few of II ranks, and one of V-VI. The oldest examples are given below.