Foghorn

Lore & Background

Audible fog signals have been used for hundreds of years, initially as seashell horns, fog bells, or gongs struck manually. At some lighthouses, a small cannon was periodically fired to warn ships, though this was labor-intensive and dangerous. In the United States, whistles were used where steam power was available, but Trinity House, the British lighthouse authority, preferred explosive signals. Throughout the 19th century, efforts were made to automate the process; Trinity House developed a system for electrically firing a gun-cotton charge, though the charge had to be manually replaced after each signal. Clockwork systems were also developed for striking bells, including a large triangle with 4-foot sides used in Maine in 1837. Ships were required to carry bells, with an exemption for Turkish ships because Islam forbade the use of bells.

The first automated steam-powered foghorn was invented by Robert Foulis, a Scotsman who emigrated to Saint John, New Brunswick, Canada. Foulis is said to have heard his daughter playing the piano in the distance on a foggy night and noticed low notes were more audible than higher notes; he then designed a device to produce a low-frequency sound, as well as a code system for use with it. Foulis repeatedly presented his concept to the Commissioners of Light Houses for the Bay of Fundy for installation on Partridge Island. The Commissioners initially rejected his plan, but one commissioner eventually encouraged Foulis to submit detailed plans. For reasons unknown, the plans were given to another Canadian engineer, T. T. Vernon Smith, who officially submitted them as his own. The foghorn was constructed at Partridge Island in 1859 as the Vernon-Smith horn. After protest by Foulis and a legislative inquiry, Foulis was credited as the true inventor, but he never patented or profited from his invention. Captain James William Newton in England also claimed to have been the inventor of the fog signalling technique using loud and low notes.

Development continued with Celadon Leeds Daboll, who invented a coal-powered foghorn called the Daboll trumpet for the American lighthouse service, though it was not universally adopted; a few remained in use until the mid-20th century. In the United Kingdom, experiments were carried out by John Tyndall and Lord Rayleigh. Rayleigh's research for Trinity House culminated in a siren with a large trumpet installed at Trevose Head Lighthouse, Cornwall in 1913. One reporter described its sound as having 'a screech like an army of panthers, weird and prolonged, gradually lowering in note until after half a minute it becomes the roar of a thousand mad bulls.' From the early 20th century, the diaphone—originally invented as an organ stop by Robert Hope-Jones and developed as a fog signal by John Northey of Toronto—became the standard foghorn apparatus for new installations worldwide, powered by compressed air and capable of extremely powerful low-frequency notes.

Reader's Guide

The foghorn's significance lies in its role as a critical navigational aid for maritime safety, especially in foggy conditions when visual markers like lighthouses are obscured. Its development reflects a long history of innovation, from manual bells and cannons to automated steam-powered systems and eventually electrically powered horns. The invention by Robert Foulis, though disputed and unprofitable for him, marked a key step toward mechanized fog signals. The diaphone, derived from organ technology, became a global standard for its powerful low-frequency sound. Foghorns also have a cultural dimension: in 1982, Dutch broadcaster VPRO aired a live 'foghorn concert' mixing sounds from multiple coastal stations with studio music. Since the 1960s and 1970s, automation and modern navigational aids like GPS have rendered many large, long-range foghorns unnecessary, according to the International Association of Lighthouse Authorities. Most older installations have been removed or replaced with simpler electrically powered horns, activated automatically by laser or photo beams that detect fog. The foghorn's legacy endures as both a practical safety device and a distinctive sound of coastal environments.

Did You Know?

• The first automated steam-powered foghorn was invented by Robert Foulis and installed at Partridge Island in 1859, though credit was initially given to another engineer.
• Some later fog bells were placed underwater so their sound would carry further and reverberate through a ship's hull, as at White Shoal Light in Michigan.
• The diaphone, originally invented as an organ stop, became the standard foghorn apparatus worldwide from the early 20th century.
• In 1982, Dutch broadcaster VPRO aired a live 'foghorn concert' on national radio, mixing sounds from multiple coastal stations with studio music.