OCR Text |
Show Sound Waves Find Fish Fishermen of Loch Fyne, Scotland, Scot-land, are catching their herring by means of electric sound waves. The electrie waves cannot be heard of! land or sea, but are produced by quartz crystal in an echometer. The instrument has been fitted to a Scottish Scot-tish west coast trawler. Waves sent out from it are echoed back from a shoal of herring, the fish having in their bodies sufficient air to react to the electrical charge transmitted. The echometer tells first when a ic near, secondly where it is. |