When Was the First Lighthouse Built?
The first known lighthouse was the Pharos of Alexandria in Egypt, a 400-foot tower built about 280 B.C. A wood fire was kept burning on the top of the tower, which became one of the Seven Wonders of the World. Before this the light from volcanoes had acted as a guide for sailors. Before the development of clearly defined ports, mariners were guided by fires built on hilltops. Since raising the fire would improve the visibility, placing the fire on a platform became a practice that led to the development of the lighthouse. In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for reefs and promontories, unlike many modern lighthouses.
The most famous lighthouse structure from antiquity was the Pharos of Alexandria, Egypt, although it collapsed during an earthquake centuries later. The intact Tower of Hercules at A Coruña, Spain gives insight into ancient lighthouse construction; other evidence about lighthouses exists in depictions on coins and mosaics, of which many represent the lighthouse at Ostia. Coins from Alexandria, Ostia, and Laodicea in Syria also exist.
The modern era of lighthouses began at the turn of the 18th century, as lighthouse construction boomed in lockstep with burgeoning levels of transatlantic commerce. Advances in structural engineering and new and efficient lighting equipment allowed for the creation of larger and more powerful lighthouses, including ones exposed to the sea. The function of lighthouses shifted toward the provision of a visible warning against shipping hazards, such as rocks or reefs.
The Eddystone Rocks were a major shipwreck hazard for mariners sailing through the English Channel. The first lighthouse built there was an octagonal wooden structure, anchored by 12 iron stanchions secured in the rock, and was built by Henry Winstanley from 1696 to 1698. His lighthouse was the first tower in the world to have been fully exposed to the open sea. The civil engineer, John Smeaton, rebuilt the lighthouse from 1756–59; his tower marked a major step forward in the design of lighthouses and remained in use until 1877. He modelled the shape of his lighthouse on that of an oak tree, using granite blocks.
He rediscovered and used “hydraulic lime,” a form of concrete that will set under water used by the Romans, and developed a technique of securing the granite blocks together using dovetail joints and marble dowels. The dovetailing feature served to improve the structural stability, although Smeaton also had to taper the thickness of the tower towards the top, for which he curved the tower inwards on a gentle gradient. This profile had the added advantage of allowing some of the energy of the waves to dissipate on impact with the walls. His lighthouse was the prototype for the modern lighthouse and influenced all subsequent engineers.
One such influence was Robert Stevenson, himself a seminal figure in the development of lighthouse design and construction. His greatest achievement was the construction of the Bell Rock Lighthouse in 1810, one of the most impressive feats of engineering of the age. This structure was based upon Smeaton’s design, but with several improved features, such as the incorporation of rotating lights, alternating between red and white.
Stevenson worked for the Northern Lighthouse Board for nearly fifty years during which time he designed and oversaw the construction and later improvement of numerous lighthouses. He innovated in the choice of light sources, mountings, reflector design, the use of Fresnel lenses, and in rotation and shuttering systems providing lighthouses with individual signatures allowing them to be identified by seafarers. He also invented the movable jib and the balance crane as a necessary part for lighthouse construction.
Alexander Mitchell designed the first screw-pile lighthouse – his lighthouse was built on piles that were screwed into the sandy or muddy seabed. Construction of his design began in 1838 at the mouth of the Thames and was known as the Maplin Sands lighthouse, and first lit in 1841. Although its construction began later, the Wyre Light in Fleetwood, Lancashire, was the first to be lit (in 1840).
The first lighthouse in Britain was built by the Romans at Dover in about A.D.43. Lighthouses continued to be built to the plan of the Pharos until about the 12th century. Then oil lamps and candles inside lanterns began to be substituted for fires. Shortly after-wards lighthouses suffered a decline which lasted until the great expansion of overseas trade and shipping began in the 16th century. This led to a revival and many lighthouses were built around the coasts of Europe. The first American lighthouse was constructed on Little Brewster Island of Boston, Massachusetts in the year 1716.
Electricity was introduced for this purpose by Britain in 1862, when electric carbon arc lamps were installed at Dungeness lighthouse on the coast of Kent. But this source of light did not come into general use until the 1920s, when high-powered filament lamps were employed. A small but powerful high-pressure electric arc lamp containing a gas called xenon was installed at Dungeness in 1961, and mercury arc lamps provide the power for one of the most modern lighthouses in the United States, that on Oak Island, North Carolina.