Democratic Sentinel, Volume 16, Number 42, Rensselaer, Jasper County, 4 November 1892 — Echoes to Order. [ARTICLE]

Echoes to Order.

The Popular Science Monthly de* scribes a curious and ingenious device called “the echo-maker," to be used on ships at sea. A flar.'ng funnel is screwed to the muzzle of a rifle. When a supposed obstacle is near the vessel the rifle is fired in its direction, and if the obstacle is there the beam of sound projected through the funnel strikes the obstacle and rebounds, and as the echo is more or less perfect in proportion as the obstacle is more or less parallel to the ship from which the gun is fired, and as it is near or remote, the position of the obstacle may be inferred. The inventor says that a sharp sound, projected at or nearly at an object, and only when so directed, wilt in every case return some of the sound sent, so that, theoretically, there will always be an echo, and the difference in the time between the sound sent and the echo will indicate the remoteness of the object. The Naval Board tried the echomaker, and found that a return sound could bo heard from the side of a fort half a mile away; from passing ste&mers a quarter of a mile away, if broadside to; from bluffs and sails of vessels at about the same distance; and from spajr buoys somewhere in the neighborhood cf two hundred and fifty yards away.