Place

Type: Military Building

The monument includes an early 20th century military early warning device known as a sound mirror. It is located on a gently sloping hillside 2km inland from the coast on the block of land between the Tyne and Wear estuaries. The mirror was part of a chain of similar acoustic devices located on the north east coast extending from the Tyne to the Humber. They were erected to provide early warning of potential attacks on the important industrial complexes in the north east from ships and Zeppelins during World War 1. Little is currently known of the history and development of this particular system and it remains something of an enigma. Successful experiments in acoustic detection date to 1915 and it is thought that the Tees/Tyne early warning system dates to the last two years of the war. This mirror faces east and was positioned to cover the approaches to the Tyne and Wear estuaries.

The mirror is a ‘U’ – shaped, concrete built structure comprising a thick wall with an inclined face and a shallow concave bowl shaped into its centre. On either side of the wall are projecting flanking walls, which helped to protect the reflection from noise interference and also supported the structure. The reflector is a smooth bowl 4.5m in diameter, inclined approximately 11 degrees to the vertical. The rear wall is 5.8m in length and is 4m high. The two flanking walls are 3.9m long. The reflected sound was detected by a microphone placed in front of the dish and then transmitted to the headphones of the operator who sat in a trench to the front. The location of the operators trench is currently unknown. It has been suggested that at this mirror the microphone was secured in front of the dish by wires attached to the side walls, so allowing it to be variably positioned. This differs from other mirrors in the north east where the microphone was fixed on a metal post in front of the dish.

The mirror is 300 metres north west of Fulwell Mill. Access is via a track off the A1018 Newcastle road northbound -turn sharp left after the Volkswagen garage.

The mirror could give about 15 minutes warning of a zeppelin raid giving time for anti-aircraft batteries and fighter aircraft to be alerted.
It is one of a chain of acoustic mirrors built along the north east coast in 1916-17 to protect north east ports from the new menace of aerial bombardment.

Listed Building entry number 920-1/4/298, Grade ll*
http://www.andrewgrantham.co.uk/soundmirrors/locations/sunderland/
See also Gillian Cookson, Sunderland building a city. (Phillimore, 2010) p. 148.

Civil Parish: Fulwell

Contributed by Simon Weathers | George Muirhead