† gas harmoniconn.Obsoleterare a musical instrument in which the sound is produced by a flame of hydrogen or other gas burning at the bottom of a glass tube; = chemical harmonicon at harmoniconn. e.
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1875 Encycl. Brit. I. 115/1Gas harmonicon consists of a small flame of hydrogen or of coal gas, burning at the lower part of the interior of a glass tube, and giving out a very distinct note.
1884 Dundee Courier & Argus 13 Mar. The complicated tones produced by a large gas harmonicon.