The Sheerophone

During the First World War, there were quite a few attempts to use acoustics to at least estimate the bearing of enemy air activity. The defense systems of Great Britain sported the acoustic mirrors, while other nations labored with various trumpet-like devices to resolve the bearing of incoming enemy aircraft. In 1916, the Italians tried using a contraption that probably later was referred to as the "sheerophone", which is pictured below. The photograph seems to be quite unique, so it may reasonable to assume that the sheereophone did not come into widespread use, The RFC (Royal Flying Corps) may have used a similar device on its aerodromes close to the front, but this has not been confirmed.