How lighthouses, and the people who ran them, changed over two thousand years
For as long as people have gone to sea, the most dangerous part of a voyage has often been its end, when a ship must find its way past rocks and sandbanks into harbour. The earliest aids to navigation were simply fires lit on hilltops near harbours. The most famous ancient beacon, however, was a purpose-built tower. The Pharos of Alexandria was completed in the third century BC at the entrance to the Egyptian port and is thought to have stood more than 100 metres high, with a fire burning at its summit. Weakened by a series of earthquakes, it had fallen into ruin by the end of the fourteenth century, yet its name lives on: the words for 'lighthouse' in French, Italian and Spanish all come from it.
The Romans, whose trade depended on safe sea routes, built lighthouses in many parts of their empire. The remains of one still stand within the grounds of Dover Castle on the English coast, and the Tower of Hercules in north-western Spain, although heavily restored in the eighteenth century, still guides ships today. After the collapse of Roman power, however, few new lights were built for many centuries. In medieval Europe, the task of showing a light to sailors often fell to monks, who kept lamps burning in chapels on headlands and islands.
The situation changed as sea trade expanded in the seventeenth and eighteenth centuries. Many of the new lighthouses along the coasts of northern Europe burned coal in open iron baskets on top of stone towers. A single station could consume more than a hundred tonnes of coal a year, all of which had to be carried up the tower by hand. Worse still, the smoke often hid the very light that sailors were searching for.
The greatest challenge was to build on isolated rocks out at sea. The Eddystone reef, south-west of Plymouth, had wrecked so many ships that a light there was attempted in the 1690s. The first tower, made of timber and designed by Henry Winstanley, was completed in 1698 but was swept away by a great storm in 1703, killing Winstanley himself. A later tower by the engineer John Smeaton, finished in 1759, proved far more durable. Smeaton, who is said to have used the trunk of an oak tree as his model, gave the tower a broad, heavy base and built it from granite blocks cut so that each one locked into its neighbours. It stood for more than a century and was replaced only because the rock beneath it was wearing away. Its upper part was taken down and rebuilt on the seafront at Plymouth, where visitors can still climb it.
Meanwhile, from the 1780s, oil lamps with circular wicks began to replace coal fires and candles, and polished metal reflectors helped to direct their light out to sea. Even so, much of the light still escaped upwards or into the tower. The decisive advance came in the 1820s, when the French physicist Augustin Fresnel designed a lens made of rings of glass prisms arranged around a central 'bull's-eye'. The lens gathered the light and bent it into a single, powerful beam that could be seen more than 30 kilometres away. Because the lens could be made to revolve, driven by clockwork, the light appeared to flash, and each lighthouse was given its own pattern of flashes, known as its 'character', so that sailors could identify it.
For the keepers, better equipment did not mean an easier life. The lamp had to be lit at sunset and watched all night; wicks had to be trimmed regularly to stop them smoking, which is why American keepers were nicknamed 'wickies'; and the clockwork that turned the lens had to be wound by hand every few hours. On rock stations, keepers had once worked in pairs, but after an incident off the Welsh coast in the early 1800s, in which one of two keepers died and his companion was left alone with the body until a boat could reach them, a team of three became the rule. Each man spent several weeks at a time on the rock before a boat brought his replacement, though storms could delay it considerably. On the mainland, by contrast, keepers often lived with their families, and wives and daughters shared much of the work.
The twentieth century gradually removed the need for keepers. In 1912, the Swedish engineer Gustaf Dalén received the Nobel Prize in Physics for inventions that included a 'sun valve', which switched a gas-powered light on at dusk and off at dawn without human help. Electric lamps, which needed far less attention than flames, spread in the following decades, and eventually many lights could be monitored and controlled from a central station hundreds of kilometres away. One by one, the keepers were withdrawn; in Britain, the last of them left their posts in 1998. Today, satellite navigation means that few sailors depend on lighthouses, yet many are still kept working as a backup, and a number of keepers' cottages are now museums or holiday homes.