a. [f. prec. + -IC, after Gr. -φωνικ-ός pertaining to voice.] Pertaining to sound produced by chemical action.
1881. in Nature, No. 622, 528. When exposed in dark to a copper plate gradually heated with an oxyhydrogen blow-pipe, no sound is heard in the telephone till the plate is raised to a dull red; then it gradually increases in intensity. The author is disposed to consider the phenomenon photophonic rather than actinophonic.
