topophonen.
/ˈtɒpəfəʊn/ (See quots.)
ΘΚΠ
society > travel > travel by water > vessel, ship, or boat > equipment of vessel > navigational aids > [noun] > other nautical instruments
clinometer1864
rhysimeter1871
oscillograph1874
topophone1880
oscillometer1899
astrograph1941
1880 Brit. Patent 495 A topophone, or instrument for locating sounds, applicable more especially to the navigation of a vessel in a fog.
1881 Standard 1 Jan. The topophone of Professor Mayer..is intended to determine the direction and approximately the distance of a fog-horn.
1902 Harper's Mag. Feb. 498 Another wireless telephone for maritime use is known as the topophone.
1902 Harper's Mag. Feb. 499 By the use of the topophone,..sounds can be heard which are inaudible to the unassisted ear.
This entry has not yet been fully updated (first published 1913; most recently modified version published online March 2018).
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n.1880