Thesaurus Term/Concept: SOUND MIRROR
| Identifier | 123555 |
|---|---|
| Class | DEFENCE OF BRITAIN |
| Status | Preferred |
| Index? | Yes |
| Scope Note | An early warning structure built during and after WWI along the south and east coasts of England. Sound detecting acoustic dishes and walls could detect the sound of approaching enemy aircraft at a distance of 8 to 15 miles. |