Lost Sounds visits a number of lighthouses at different times over the last 130 years to reveal the philanthropic, scientific and romantic story of the fog signal - how it came about, how the machinery worked and, for the mariner and the keeper, what it sounded like! The development of fog signals complemented the expansion of lighthouse construction worldwide from the last quarter of the 19th century and represented the attempt to provide a vital navigation aid to mariners when the beam of light from the lighthouses lens was obscured by fog. Lost Sounds reveals the practical development of sound signals from the early percussion instruments to the later succession of compressed-air sirens and diaphones through to the last remaining electric emitters. However, it is much more than that - it is a record of another part of maritime history.