Show sound waves find fish fishermen of loch fyne scotland are ara catching their herring by means of electric sound waves the tha electric waves cannot be heard on land or sea but are produced by quartz quarts crystal in an the instrument has been fitted to a scot tish west coast trawler waves sent out from it are echoed back from a shoal of herring the fish elsh ha having ving in their bodies sufficient clent air to react to the electrical charge transmitted the tells first when a shoal is near secondly where itis |