In ancient times, it seems, the town of Arbroath, near the Firth of Tay in Scotland, was widely known by the much more sonorous name of Aberbrothok. It boasted, or indeed may even have comprised, a monastery, whose abbot became increasingly distressed at the regular fatalities as ships, passing by in fog, fell foul of the Inchcape Rock.
He decreed that a bell be fixed on a timber float and anchored to the rock as an acoustic aid to sailors - an event celebrated in a well-known ballad by Robert Southey:
Then they knew the perilous]rock / And blessed the Abbot of Aberbrothok.
In the very early days of seafaring, any crude device for making noise was a help to sailors trying to navigate in fog. Fishermen's wives, waiting ashore for husbands to return, would create a din with cooking-pans, or whistle through the mist to guide their menfolk home. Sailors themselves would shout and listen for the echoes through the fog to judge their distance from any nearby cliffs or headlands.
Pounding drums were used to guide the Vikings safely into harbour, and the Imperial Gong was an honoured navigational aid in ancient China.
With the invention of gunpowder, and for many centuries thereafter, cannons ashore were often used to sound a warning, one of the most famous being the gun which, from 1719 onwards, boomed at half-hourly intervals over Boston harbour. Manually operated fog-bells were also common during the early 1800s, and as the century progressed the Victorians used their ingenuity to equip many of these with mechanical strikers of the cleverest design.
The 1850s saw the development of a new kind of fog signal - a horn in which compressed air was used to vibrate a diaphragm or reed. And from this it was only a short step to the device still in common use today - the diaphone.
Early versions of the diaphone were supplied with compressed air by means of steam engines, and in a spell of foggy weather the hungry monsters had to be fed great quantities of coal.
The Abbot of Arbroath's medieval innovation, however, seems to have been the prototype for purpose-built fog signals. But vandalism, alas, was rife in those days too. Shortly after its installation a pirate chief called Ralph the Rover allegedly cut the bell adrift - only to be wrecked himself upon the self-same rock a year later. Southey again tells us what happened, and of Ralph's reaction as the event occurred:
The vessel strikes with a shivering shock.
O Christ! It is the Inchcape Rock!