[f. FORM(IC) + -ENE.] Methane or marsh-gas (CH4). Hence Formenophone [Gr. φωνή sound]: see quot.
1884. Athenæum, 19 July, 86/3. Formene, when slightly condensed and cooled in boiling ethylene under atmospheric pressure is resolved into an extremely volatile colourless fluid, which in again passing to the gaseous state yields a degree of cold sufficient to liquefy oxygen.
1894. Pop. Sci. Monthly, XLIV. Feb., 576/2. An instrument which he calls a formenophone has been invented by a French engineer, M. E. Hardy, for detecting the presence and estimating the proportions of gaseous impurities of an atmosphere by the sound they give in a pipe.
