trumpet has a parabolically shaped extension.
Another has cylinders provided with interior clapper-valves near the heads; these admit air when the water recedes, but prevent its escape at the valveway when the water rises; the air has its exit through the whistles, and sounds the alarm.
Another has two whistles and a single mouth-piece, the aim being to produce discordant sounds, which arrest attention.
A very large fog-whistle, worked by a ten-horsepower engine, is placed on Thatcher's Island, off Salem, Mass.
A bell upon a vessel, buoy, or spit of land, and rung by the motion of the waves or force of the wind, as a warning to mariners.
（Mining.) A forge for smelting tin. (Cornwall.)
A horn or trumpet placed on a projecting headland, a vessel, or a spar, and blown by mechanical means or by the wind, as a warning to mariners.