![Aveiro March 2012-13](https://upload.wikimedia.org/wikipedia/commons/a/ae/Aveiro_March_2012-13.jpg)
A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and
lenses
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
and to serve as a
beacon
A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More mode ...
for
navigational aid, for
maritime pilot
A maritime pilot, marine pilot, harbor pilot, port pilot, ship pilot, or simply pilot, is a mariner who maneuvers ships through dangerous or congested waters, such as harbors or river mouths. Maritime pilots are regarded as skilled profession ...
s at sea or on inland waterways.
Lighthouses mark dangerous coastlines, hazardous
shoals,
reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...
s, rocks, and safe entries to harbors; they also assist in
aerial navigation
The basic principles of air navigation are identical to general navigation, which includes the process of planning, recording, and controlling the movement of a craft from one place to another.
Successful air navigation involves piloting an air ...
. Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and has become uneconomical since the advent of much cheaper, more sophisticated and effective electronic navigational systems.
History
Ancient lighthouses
![A coruna torre de hercules sunset edit](https://upload.wikimedia.org/wikipedia/commons/e/eb/A_coruna_torre_de_hercules_sunset_edit.jpg)
Before the development of clearly defined
port
A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as H ...
s, mariners were guided by fires built on hilltops. Since elevating 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
reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...
s and
promontories
A promontory is a raised mass of land that projects into a lowland or a body of water (in which case it is a peninsula). Most promontories either are formed from a hard ridge of rock that has resisted the erosive forces that have removed the so ...
, unlike many modern lighthouses. The most famous lighthouse structure from antiquity was the
Pharos
The Lighthouse of Alexandria, sometimes called the Pharos of Alexandria (; Ancient Greek: ὁ Φάρος τῆς Ἀλεξανδρείας, contemporary Koine ), was a lighthouse built by the Ptolemaic Kingdom of Ancient Egypt, during the re ...
of
Alexandria
Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandri ...
,
Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Medit ...
, which collapsed following a series of earthquakes between 956 CE and 1323 CE.
The intact
Tower of Hercules
The Tower of Hercules ( es, Torre de Hércules) is the oldest existent lighthouse known. It has an ancient Roman origin on a peninsula about from the centre of A Coruña, Galicia, in north-western Spain. Until the 20th century, it was known a ...
at
A Coruña
A Coruña (; es, La Coruña ; historical English: Corunna or The Groyne) is a city and municipality of Galicia, Spain. A Coruña is the most populated city in Galicia and the second most populated municipality in the autonomous community and s ...
, 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
Laodicea ( grc, Λαοδίκεια) was a port city and an important colonia of the Roman Empire in ancient Syria, located near the modern city of Latakia. It was also called Laodicea in Syria or Laodicea ad mare. For a short period of time un ...
also exist.
Modern construction
The modern era of lighthouses began at the turn of the 18th century, as the number of lighthouses being constructed increased significantly due to much higher levels of
transatlantic
Transatlantic, Trans-Atlantic or TransAtlantic may refer to:
Film
* Transatlantic Pictures, a film production company from 1948 to 1950
* Transatlantic Enterprises, an American production company in the late 1970s
* ''Transatlantic'' (1931 film) ...
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 was gradually changed from indicating ports to the providing of a visible warning against shipping hazards, such as rocks or reefs.
![Edystone Winstanley lighthouse Smeaton 1813](https://upload.wikimedia.org/wikipedia/commons/2/2a/Edystone_Winstanley_lighthouse_Smeaton_1813.jpg)
The
Eddystone Rocks were a major shipwreck hazard for mariners sailing through the
English Channel
The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" (Cotentinais) or ( Jèrriais), (Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kana ...
. 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
John Smeaton (8 June 1724 – 28 October 1792) was a British civil engineer responsible for the design of bridges, canals, harbours and lighthouses. He was also a capable mechanical engineer and an eminent physicist. Smeaton was the fi ...
rebuilt the
lighthouse from 1756 to 1759;
[Majdalany, Fred: ''The Eddystone Light''. 1960] his tower marked a major step forward in the design of lighthouses and remained in use until 1877. He modeled 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.
![Smeaton's Lighthouse00](https://upload.wikimedia.org/wikipedia/commons/6/61/Smeaton%27s_Lighthouse00.jpg)
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
The Bell Rock Lighthouse, off the coast of Angus, Scotland, is the world's oldest surviving sea-washed lighthouse. It was built between 1807 and 1810 by Robert Stevenson on the Bell Rock (also known as Inchcape) in the North Sea, east of the ...
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
The Northern Lighthouse Board (NLB) is the general lighthouse authority for Scotland and the Isle of Man. It is a non-departmental public body responsible for marine navigation aids around coastal areas.
History
The NLB was formed by Act of P ...
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 lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships."
The design allows the c ...
es, 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
A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by the blind Irish engineer Alexander Mitchell. Constructio ...
– his lighthouse was built on piles that were
screw
A screw and a bolt (see '' Differentiation between bolt and screw'' below) are similar types of fastener typically made of metal and characterized by a helical ridge, called a ''male thread'' (external thread). Screws and bolts are used to f ...
ed into the sandy or muddy seabed. Construction of his design began in 1838 at the mouth of the
Thames
The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the R ...
and was known as the
Maplin Sands
The Maplin Sands are mudflats on the northern bank of the Thames estuary, off Foulness Island, near Southend-on-Sea in Essex, England, though they actually lie within the neighbouring borough of Rochford. They form a part of the Essex Estuarie ...
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).
Lighting improvements
Until 1782 the source of illumination had generally been wood pyres or burning coal. The
Argand lamp
The Argand lamp is a type of oil lamp invented in 1780 by Aimé Argand. Its output is 6 to 10 candelas, brighter than that of earlier lamps. Its more complete combustion of the candle wick and oil than in other lamps required much less frequent ...
, invented in 1782 by the Swiss scientist
Aimé Argand
François-Pierre-Amédée Argand, known as Ami Argand (5 July 1750 – 14 or 24 October 1803) was a Genevan physicist and chemist. He invented the Argand lamp, a great improvement on the traditional oil lamp.
Early years
Francois-Pierre-Améd ...
revolutionized lighthouse illumination with its steady smokeless flame. Early models used ground glass which was sometimes tinted around the wick. Later models used a
mantle of
thorium dioxide
Thorium dioxide (ThO2), also called thorium(IV) oxide, is a crystalline solid, often white or yellow in colour. Also known as thoria, it is produced mainly as a by-product of lanthanide and uranium production. Thorianite is the name of the minera ...
suspended over the flame, creating a bright, steady light. The Argand lamp used
whale oil
Whale oil is oil obtained from the blubber of whales. Whale oil from the bowhead whale was sometimes known as train oil, which comes from the Dutch word ''traan'' (" tear" or "drop").
Sperm oil, a special kind of oil obtained from the head ...
,
colza
Close-up of canola blooms
Canola flower
Rapeseed oil is one of the oldest known vegetable oils. There are both edible and industrial forms produced from rapeseed, the seed of several cultivars of the plant family Brassicaceae. Historically, i ...
,
olive oil or other
vegetable oil
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or f ...
as fuel, supplied by a
gravity feed
Gravity feed is the use of earth's gravity to move something (usually a liquid) from one place to another. It is a simple means of moving a liquid without the use of a pump. A common application is the supply of fuel to an internal combustion ...
from a reservoir mounted above the burner. The lamp was first produced by
Matthew Boulton
Matthew Boulton (; 3 September 172817 August 1809) was an English manufacturer and business partner of Scottish engineer James Watt. In the final quarter of the 18th century, the partnership installed hundreds of Boulton & Watt steam engin ...
, in partnership with Argand, in 1784, and became the standard for lighthouses for over a century.
South Foreland Lighthouse
South Foreland Lighthouses are a pair of Victorian lighthouses on the South Foreland in St. Margaret's Bay, Dover, Kent, England, used to warn ships approaching the nearby Goodwin Sands. There has been a pair of lighthouses at South Forelan ...
was the first tower to successfully use an electric light in 1875. The lighthouse's carbon
arc lamps were powered by a steam-driven
magneto
A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Unlike a dynamo, a magneto does not contain a commutator to produce direct current. It is categorized as a form of alternator, ...
.
John Richardson Wigham was the first to develop a system for
gas
Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma).
A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or ...
illumination of lighthouses. His improved gas 'crocus' burner at the
Baily Lighthouse near Dublin was 13 times more powerful than the most brilliant light then known.
![Sumburgh Lighthouse Lamp](https://upload.wikimedia.org/wikipedia/commons/7/71/Sumburgh_Lighthouse_Lamp.jpg)
The vaporized
oil burner
An oil burner is a heating device which burns #1, #2 and #6 heating oils, diesel fuel or other similar fuels. In the United States ultra low #2 diesel is the common fuel used. It is dyed red to show that it is road-tax exempt. In most markets ...
was invented in 1901 by
Arthur Kitson, and improved by David Hood at
Trinity House
"Three In One"
, formation =
, founding_location = Deptford, London, England
, status = Royal Charter corporation and registered charity
, purpose = Maintenance of lighthouses, buoys and beacons
, he ...
. The fuel was vaporized at high pressure and burned to heat the mantle, giving an output of over six times the luminosity of traditional oil lights. The use of gas as illuminant became widely available with the invention of the
Dalén light
A Dalén light is a light produced from burning of carbide gas (acetylene), combined with a solar sensor which automatically operates the light only during darkness.
Overview
The technology was the predominant form of light source in lighthouse ...
by Swedish engineer
Gustaf Dalén
Nils Gustaf Dalén (; 30 November 1869 – 9 December 1937) was a Swedish Nobel Laureate and industrialist, engineer, inventor and long-term CEO of the AGA AB, AGA company and inventor of the AGA cooker and the Dalén light. In 1912 he was award ...
. He used
Agamassan
Agamassan is a porous substrate used to safely absorb acetylene and thus allow the transport, storage and commercial use of the otherwise unstable gas. It was developed and patented by the Swedish Nobel Laureate and industrialist Gustaf Dalén. ...
(Aga), a
substrate, to absorb the gas, allowing the gas to be stored, and hence used, safely. Dalén also invented the '
sun valve', which automatically regulated the light and turned it off during the daytime. The technology was the predominant light source in lighthouses from the 1900s to the 1960s, when electric lighting had become dominant.
Optical systems
![Fresnel lighthouse lens diagram](https://upload.wikimedia.org/wikipedia/commons/a/ab/Fresnel_lighthouse_lens_diagram.png)
With the development of the steady illumination of the Argand lamp, the application of optical lenses to increase and focus the light intensity became a practical possibility.
William Hutchinson developed the first practical optical system in 1763, known as a
catoptric
Catoptrics (from grc-gre, κατοπτρικός ''katoptrikós'', "specular", from grc-gre, κάτοπτρον ''katoptron'' "mirror") deals with the phenomena of reflected light and image-forming optical systems using mirrors. A catoptric ...
system. This rudimentary system effectively collimated the emitted light into a concentrated beam, thereby greatly increasing the light's visibility. The ability to focus the light led to the first revolving lighthouse beams, where the light would appear to the mariners as a series of intermittent flashes. It also became possible to transmit complex signals using the light flashes.
French physicist and engineer
Augustin-Jean Fresnel
Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and physicist whose research in optics led to the almost unanimous acceptance of the wave theory of light, excluding any remnant of Newton's corpuscular th ...
developed the multi-part
Fresnel lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships."
The design allows the c ...
for use in lighthouses. His design allowed for the construction of lenses of large
aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane.
An ...
and short
focal length, without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. A Fresnel lens can also capture more oblique light from a light source, thus allowing the light from a lighthouse equipped with one to be visible over greater distances.
The first Fresnel lens was used in 1823 in the
Cordouan lighthouse
Cordouan lighthouse () is an active lighthouse located at sea, near the mouth of the Gironde estuary in France. At a height of , it is the tenth-tallest "traditional lighthouse" in the world.
The Tour de Cordouan, the 'Patriarch of Lighthouses ...
at the mouth of the
Gironde estuary; its light could be seen from more than out. Fresnel's invention increased the
luminosity of the lighthouse lamp by a factor of four and his system is still in common use.
Modern lighthouses
The introduction of electrification and
automatic lamp changers began to make
lighthouse keeper
A lighthouse keeper or lightkeeper is a person responsible for tending and caring for a lighthouse, particularly the light and lens in the days when oil lamps and clockwork mechanisms were used. Lighthouse keepers were sometimes referred to as ...
s obsolete. For many years, lighthouses still had keepers, partly because lighthouse keepers could serve as a
rescue service if necessary. Improvements in maritime navigation and safety such as
satellite navigation
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pr ...
systems such as
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
led to the phasing out of non-automated lighthouses across the world. In Canada, this trend has been stopped and there are still 50 staffed light stations, with 27 on the west coast alone.
Remaining modern lighthouses are usually illuminated by a single stationary flashing light powered by solar-charged batteries mounted on a steel skeleton tower.
Where the power requirement is too great for solar power, ''cycle charging'' by diesel generator is used: to save fuel and to increase periods between maintenance the light is battery powered, with the generator only coming into use when the battery has to be charged.
Famous lighthouse builders
John Smeaton
John Smeaton (8 June 1724 – 28 October 1792) was a British civil engineer responsible for the design of bridges, canals, harbours and lighthouses. He was also a capable mechanical engineer and an eminent physicist. Smeaton was the fi ...
is noteworthy for having designed the third and most famous
Eddystone Lighthouse
The Eddystone Lighthouse is a lighthouse that is located on the dangerous Eddystone Rocks, south of Rame Head in Cornwall, England. The rocks are submerged below the surface of the sea and are composed of Precambrian gneiss. View at 1:50000 ...
, but some builders are well known for their work in building multiple lighthouses. The Stevenson family (
Robert
The name Robert is an ancient Germanic given name, from Proto-Germanic "fame" and "bright" (''Hrōþiberhtaz''). Compare Old Dutch ''Robrecht'' and Old High German ''Hrodebert'' (a compound of '' Hruod'' ( non, Hróðr) "fame, glory, honou ...
,
Alan,
David
David (; , "beloved one") (traditional spelling), , ''Dāwūd''; grc-koi, Δαυΐδ, Dauíd; la, Davidus, David; gez , ዳዊት, ''Dawit''; xcl, Դաւիթ, ''Dawitʿ''; cu, Давíдъ, ''Davidŭ''; possibly meaning "beloved one". w ...
,
Thomas
Thomas may refer to:
People
* List of people with given name Thomas
* Thomas (name)
* Thomas (surname)
* Saint Thomas (disambiguation)
* Thomas Aquinas (1225–1274) Italian Dominican friar, philosopher, and Doctor of the Church
* Thomas the A ...
,
David Alan, and
Charles) made lighthouse building a three-generation profession in Scotland.
Richard Henry Brunton
Richard Henry Brunton FRGS MICE (26 December 1841 – 24 April 1901) was the so-called " Father of Japanese lighthouses". Brunton was born in Muchalls, Kincardineshire, Scotland. He was employed by the government of Meiji period Japan as ...
designed and built 26
Japanese lighthouses in
Meiji Era Japan, which became known as Brunton's "children". Blind Irishman
Alexander Mitchell invented and built a number of screw-pile lighthouses. Englishman
James Douglass was knighted for his work on the fourth Eddystone Lighthouse.
Lieutenant
George Meade
George Gordon Meade (December 31, 1815 – November 6, 1872) was a United States Army officer and civil engineer best known for decisively defeating Confederate General Robert E. Lee at the Battle of Gettysburg in the American Civil War. H ...
built numerous lighthouses along the Atlantic and Gulf coasts before gaining wider fame as the winning general at the
Battle of Gettysburg
The Battle of Gettysburg () was fought July 1–3, 1863, in and around the town of Gettysburg, Pennsylvania, by Union and Confederate forces during the American Civil War. In the battle, Union Major General George Meade's Army of the Po ...
. Colonel
Orlando M. Poe, engineer to
General William Tecumseh Sherman in the siege of Atlanta, designed and built some of the most exotic lighthouses in the most difficult locations on the U.S.
Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lak ...
.
French merchant navy officer
Marius Michel Pasha
Blaise-Jean-Marius Michel, Comte de Pierredon (1819-1907), also known as Michel Pasha or Michel Pacha in French, was a French architect and lighthouse builder.
Early life
He was born in Sanary, near Toulon, Provence, in 1819. He became a merchan ...
built almost a hundred lighthouses along the coasts of the
Ottoman Empire
The Ottoman Empire, * ; is an archaic version. The definite article forms and were synonymous * and el, Оθωμανική Αυτοκρατορία, Othōmanikē Avtokratoria, label=none * info page on book at Martin Luther University) ...
in a period of twenty years after the
Crimean War
The Crimean War, , was fought from October 1853 to February 1856 between Russia and an ultimately victorious alliance of the Ottoman Empire, France, the United Kingdom and Piedmont-Sardinia.
Geopolitical causes of the war included the ...
(1853–1856).
Technology
In a lighthouse, the source of light is called the "lamp" (whether electric or fuelled by oil) and the light is concentrated, if needed, by the "lens" or "optic". Power sources for lighthouses in the 20th–21st centuries vary.
Power
Originally lit by open fires and later candles, the
Argand hollow wick lamp and
parabolic reflector
A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface gener ...
were introduced in the late 18th century.
Whale oil
Whale oil is oil obtained from the blubber of whales. Whale oil from the bowhead whale was sometimes known as train oil, which comes from the Dutch word ''traan'' (" tear" or "drop").
Sperm oil, a special kind of oil obtained from the head ...
was also used with wicks as the source of light.
Kerosene
Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning "wax", and was regi ...
became popular in the 1870s and electricity and carbide (
acetylene gas
Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure f ...
) began replacing kerosene around the turn of the 20th century.
Carbide was promoted by the
Dalén light
A Dalén light is a light produced from burning of carbide gas (acetylene), combined with a solar sensor which automatically operates the light only during darkness.
Overview
The technology was the predominant form of light source in lighthouse ...
which automatically lit the lamp at nightfall and extinguished it at dawn.
During the
Cold War, many remote Soviet lighthouses were powered by
radioisotope thermoelectric generator
A radioisotope thermoelectric generator (RTG, RITEG), sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioacti ...
s (RTGs). These had the advantage of providing power day or night and did not need refuelling or maintenance. However, after the breakdown of the Soviet Union, there are no official records of the locations or condition of all of these lighthouses. As time passes, their condition is degrading; many have fallen victim to vandalism and scrap metal thieves, who may not be aware of the dangerous radioactive contents.
Energy-efficient LED lights can be powered by
solar panels, with batteries instead of a diesel generator for backup.
[
]
Light source
Many Fresnel lens installations have been replaced by rotating aerobeacon
An aerobeacon is a light assembly used to create a fixed or flashing signal visible over long distances. It consists of a high intensity electric lamp mounted with a focusing device in a cylindrical housing, which usually is rotated on a vertical ...
s which require less maintenance.
In modern automated lighthouses, the system of rotating lenses is often replaced by a high intensity light that emits brief omnidirectional flashes, concentrating the light in time rather than direction. These lights are similar to obstruction lights used to warn aircraft of tall structures. Later innovations were "Vega Lights", and experiments with light-emitting diode
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (co ...
(LED) panels.
LED lights, which use less energy and are easier to maintain, had come into widespread use by 2020. In the United Kingdom and Ireland about a third of lighthouses had been converted from filament light sources to use LEDs, and conversion continued with about three per year. The light sources are designed to replicate the colour and character of the traditional light as closely as possible. The change is often not noticed by people in the region, but sometimes a proposed change leads to calls to preserve the traditional light, including in some cases a rotating beam. A typical LED system designed to fit into the traditional 19th century Fresnel lens enclosure was developed by Trinity House and two other lighthouse authorities and costs about €
The euro sign () is the currency sign used for the euro, the official currency of the eurozone and unilaterally adopted by Kosovo and Montenegro. The design was presented to the public by the European Commission on 12 December 1996. It consists ...
20,000, depending on configuration, according to a supplier; it has large fins to dissipate heat. Lifetime of the LED light source is 50,000 to 100,000 hours, compared to about 1,000 hours for a filament source.
Laser light
Experimental installations of laser lights, either at high power to provide a "line of light" in the sky or, utilising low power, aimed towards mariners have identified problems of increased complexity in installation and maintenance, and high power requirements. The first practical installation, in 1971 at Point Danger lighthouse
Point Danger Light, also known as the Captain Cook Memorial Light, is an active lighthouse located on Point Danger, a headland between Coolangatta and Tweed Heads, marking the border between Queensland and New South Wales, Australia. It la ...
, Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, establishe ...
, was replaced by a conventional light after four years because the beam was too narrow to be seen easily.
Light characteristics
In any of these designs an observer, rather than seeing a continuous weak light, sees a brighter light during short time intervals. These instants of bright light are arranged to create a light characteristic
A light characteristic is all of the properties that make a particular navigational light identifiable. Graphical and textual descriptions of navigational light sequences and colours are displayed on nautical charts and in Light Lists with the cha ...
or pattern specific to a lighthouse. For example, the Scheveningen Lighthouse
De Scheveningen Lighthouse is a lighthouse in Scheveningen, Netherlands. It was designed by Quirinus Harder and activated finished in 1875.
History
In the 16th century Scheveningen had a lighthouse already, and the church collected money from ...
flashes are alternately 2.5 and 7.5 seconds. Some lights have sectors of a particular color (usually formed by colored panes in the lantern) to distinguish safe water areas from dangerous shoals. Modern lighthouses often have unique reflectors or Racon transponders so the radar signature of the light is also unique.
Lens
Before modern strobe light
A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. It is one of a number of devices that can be used as a stroboscope. The word originated from the Ancient Greek ('), meaning ...
s, lenses
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
were used to concentrate the light from a continuous source. Vertical light rays of the lamp are redirected into a horizontal plane, and horizontally the light is focused into one or a few directions at a time, with the light beam
A light beam or beam of light is a directional projection of light energy radiating from a light source. Sunlight forms a light beam (a sunbeam) when filtered through media such as clouds, foliage, or windows. To artificially produce a light ...
swept around. As a result, in addition to seeing the side of the light beam, the light is directly visible from greater distances, and with an identifying light characteristic
A light characteristic is all of the properties that make a particular navigational light identifiable. Graphical and textual descriptions of navigational light sequences and colours are displayed on nautical charts and in Light Lists with the cha ...
.
This concentration of light is accomplished with a rotating lens assembly. In early lighthouses, the light source was a kerosene lamp or, earlier, an animal or vegetable oil Argand lamp, and the lenses rotated by a weight driven clockwork assembly wound by lighthouse keepers, sometimes as often as every two hours. The lens assembly sometimes floated in liquid mercury to reduce friction. In more modern lighthouses, electric lights and motor drives were used, generally powered by diesel electric generators. These also supplied electricity for the lighthouse keepers.
Efficiently concentrating the light from a large omnidirectional light source requires a very large diameter lens. This would require a very thick and heavy lens if a conventional lens were used. The Fresnel lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships."
The design allows the c ...
(pronounced ) focused 85% of a lamp's light versus the 20% focused with the parabolic reflectors of the time. Its design enabled construction of lenses of large size and short focal length without the weight and volume of material in conventional lens designs.[
Fresnel lighthouse lenses are ranked by ''order'', a measure of refracting power, with a first order lens being the largest, most powerful and expensive; and a sixth order lens being the smallest. The order is based on the focal length of the lens. A first order lens has the longest focal length, with the sixth being the shortest. Coastal lighthouses generally use first, second, or third order lenses, while harbor lights and beacons use fourth, fifth, or sixth order lenses.][
Some lighthouses, such as those at ]Cape Race
Cape Race is a point of land located at the southeastern tip of the Avalon Peninsula on the island of Newfoundland, in Newfoundland and Labrador, Canada. Its name is thought to come from the original Portuguese name for this cape, "Raso", mean ...
, Newfoundland, and Makapuu Point, Hawaii, used a more powerful hyperradiant Fresnel lens
Hyper-radial or hyperradiant Fresnel lenses are Fresnel lenses used in lighthouses. They are larger than "first-order" lenses, having a focal length (radius) of 1330 mm (52.36 inches). The idea was mentioned by Thomas Stevenson in 1869 and ...
manufactured by the firm of Chance Brothers
Chance Brothers and Company was a glassworks originally based in Spon Lane, Smethwick, West Midlands (formerly in Staffordshire), in England. It was a leading glass manufacturer and a pioneer of British glassmaking technology.
The Chance fam ...
.
Building
Components
While lighthouse buildings differ depending on the location and purpose, they tend to have common components.
A light station comprises the lighthouse tower and all outbuildings, such as the keeper's living quarters, fuel house, boathouse, and fog-signaling building. The Lighthouse itself consists of a tower structure supporting the lantern room where the light operates.
The lantern room is the glassed-in housing at the top of a lighthouse tower containing the lamp and lens. Its glass storm panes are supported by metal muntin
A muntin (US), muntin bar, glazing bar (UK), or sash bar is a strip of wood or metal separating and holding panes of glass in a window. Muntins can be found in doors, windows, and furniture, typically in Western styles of architecture. Muntins ...
s (glazing bars) running vertically or diagonally. At the top of the lantern room is a stormproof ventilator designed to remove the smoke of the lamps and the heat that builds in the glass enclosure. A lightning rod
A lightning rod or lightning conductor (British English) is a metal rod mounted on a structure and intended to protect the structure from a lightning strike. If lightning hits the structure, it will preferentially strike the rod and be conducte ...
and grounding system connected to the metal cupola roof provides a safe conduit for any lightning strikes.
Immediately beneath the lantern room is usually a Watch Room or Service Room where fuel and other supplies were kept and where the keeper prepared the lanterns for the night and often stood watch. The clockworks (for rotating the lenses) were also located there. On a lighthouse tower, an open platform called the gallery is often located outside the watch room (called the Main Gallery) or Lantern Room (Lantern Gallery). This was mainly used for cleaning the outside of the windows of the Lantern Room.
Lighthouses near to each other that are similar in shape are often painted in a unique pattern so they can easily be recognized during daylight, a marking known as a daymark
A daymark is a navigational aid for sailors and pilots, distinctively marked to maximize its visibility in daylight.
The word is also used in a more specific, technical sense to refer to a signboard or daytime identifier that is attached to ...
. The black and white barber pole spiral pattern of Cape Hatteras Lighthouse
Cape Hatteras Light is a lighthouse located on Hatteras Island in the Outer Banks in the town of Buxton, North Carolina and is part of the Cape Hatteras National Seashore. The lighthouse’s semi-unique pattern makes it easy to recognize and famou ...
is one example. Race Rocks Light in western Canada is painted in horizontal black and white bands to stand out against the horizon.
Design
For effectiveness, the lamp must be high enough to be seen before the danger is reached by a mariner. The minimum height is calculated by trigonometric formula where ''H'' is the height above water in feet, and ''d'' is the distance to the horizon in nautical miles.
Where dangerous shoals are located far off a flat sandy beach, the prototypical tall masonry coastal lighthouse is constructed to assist the navigator making a landfall after an ocean crossing. Often these are cylindrical to reduce the effect of wind on a tall structure, such as Cape May Light. Smaller versions of this design are often used as harbor lights to mark the entrance into a harbor, such as New London Harbor Light
New London Harbor Light is a lighthouse in Connecticut on the west side of the New London harbor entrance. It is the nation's fifth oldest light station and the seventh oldest U.S. lighthouse. It is both the oldest and the tallest lighthouse in Co ...
.
Where a tall cliff exists, a smaller structure may be placed on top such as at Horton Point Light. Sometimes, such a location can be too high, for example along the west coast of the United States, where frequent low clouds can obscure the light. In these cases, lighthouses are placed below the clifftop to ensure that they can still be seen at the surface during periods of fog or low clouds, as at Point Reyes Lighthouse
The Point Reyes Lighthouse, also known as Point Reyes Light or the Point Reyes Light Station, is a lighthouse in the Gulf of the Farallones on Point Reyes in Point Reyes National Seashore, located in Marin County, California, United States.
The ...
. Another example is in San Diego
San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the eighth most populous city in the United State ...
, California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
: the Old Point Loma lighthouse was too high up and often obscured by fog, so it was replaced in 1891 with a lower lighthouse, New Point Loma lighthouse
The New Point Loma Lighthouse (officially Point Loma Light) is a lighthouse at the southern tip of the Point Loma peninsula in San Diego, California.
History
It was first lighted on March 23, 1891, replacing the Old Point Loma Lighthouse whic ...
.
As technology advanced, prefabricated skeletal iron or steel structures tended to be used for lighthouses constructed in the 20th century. These often have a narrow cylindrical core surrounded by an open lattice work bracing, such as Finns Point Range Light.
Sometimes a lighthouse needs to be constructed in the water itself. Wave-washed lighthouses are masonry structures constructed to withstand water impact, such as Eddystone Lighthouse
The Eddystone Lighthouse is a lighthouse that is located on the dangerous Eddystone Rocks, south of Rame Head in Cornwall, England. The rocks are submerged below the surface of the sea and are composed of Precambrian gneiss. View at 1:50000 ...
in Britain and the St. George Reef Light of California. In shallower bays, Screw-pile lighthouse
A screw-pile lighthouse is a lighthouse which stands on piles that are screwed into sandy or muddy sea or river bottoms. The first screw-pile lighthouse to begin construction was built by the blind Irish engineer Alexander Mitchell. Constructio ...
ironwork structures are screwed into the seabed and a low wooden structure is placed above the open framework, such as Thomas Point Shoal Lighthouse. As screw piles can be disrupted by ice, steel caisson lighthouses such as Orient Point Light are used in cold climates. Orient Long Beach Bar Light (Bug Light) is a blend of a screw pile light that was converted to a caisson light because of the threat of ice damage. Skeletal iron towers with screw-pile foundations were built on the Florida Reef
The Florida Reef (also known as the Great Florida Reef, Florida reefs, Florida Reef Tract and Florida Keys Reef Tract) is the only living coral barrier reef in the continental United States. It is the third largest coral barrier reef system in ...
along the Florida Keys, beginning with the Carysfort Reef Light
Carysfort Reef Light is located approximately six nautical miles east of Key Largo, Florida. The lighthouse has an iron screw-pile foundation with a platform, and a skeletal, octagonal, pyramidal tower, which is painted red. The light is above ...
in 1852.
In waters too deep for a conventional structure, a lightship might be used instead of a lighthouse, such as the former lightship ''Columbia''. Most of these have now been replaced by fixed light platforms (such as Ambrose Light
Ambrose Light, often called Ambrose Tower, was the light station at the convergence of several major shipping lanes in Lower New York Bay, including Ambrose Channel, the primary passage for ships entering and departing the Port of New York and ...
) similar to those used for offshore oil exploration.
Range lights
Aligning two fixed points on land provides a navigator with a line of position
A position line or line of position (LOP) is a line (or, on the surface of the earth, a curve) that can be both identified on a chart (nautical chart or aeronautical chart) and translated to the surface of the earth. The intersection of a minimum o ...
called a range in North America and a transit
Transit may refer to:
Arts and entertainment Film
* ''Transit'' (1979 film), a 1979 Israeli film
* ''Transit'' (2005 film), a film produced by MTV and Staying-Alive about four people in countries in the world
* ''Transit'' (2006 film), a 2006 ...
in Britain. Ranges can be used to precisely align a vessel within a narrow channel such as a river. With landmarks of a range illuminated with a set of fixed lighthouses, nighttime navigation is possible.
Such paired lighthouses are called range lights in North America and leading lights
Leading lights (also known as range lights in the United States) are a pair of light beacons used in navigation to indicate a safe passage for vessels entering a shallow or dangerous channel; they may also be used for position fixing. At nigh ...
in the United Kingdom. The closer light is referred to as the beacon or front range; the further light is called the rear range. The rear range light is almost always taller than the front.
When a vessel is on the correct course, the two lights align vertically, but when the observer is out of position, the difference in alignment indicates the direction of travel to correct the course.
Location
There are two types of lighthouses: ones that are located on land, and ones that are offshore.
''Offshore Lighthouses'' are lighthouses that are not close to land. There can be a number of reasons for these lighthouses to be built. There can be a shoal, reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock o ...
or submerged island
An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island ...
several miles from land.
The current Cordouan Lighthouse
Cordouan lighthouse () is an active lighthouse located at sea, near the mouth of the Gironde estuary in France. At a height of , it is the tenth-tallest "traditional lighthouse" in the world.
The Tour de Cordouan, the 'Patriarch of Lighthouses ...
was completed in 1611, from the shore on a small islet, but was built on a previous lighthouse that can be traced back to the 880's and is the oldest surviving lighthouse in France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan area ...
. It is connected to the mainland by a causeway. The oldest surviving oceanic offshore lighthouse is Bell Rock Lighthouse
The Bell Rock Lighthouse, off the coast of Angus, Scotland, is the world's oldest surviving sea-washed lighthouse. It was built between 1807 and 1810 by Robert Stevenson on the Bell Rock (also known as Inchcape) in the North Sea, east of the ...
in the North Sea
The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea, epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the ...
, off the coast of Scotland
Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...
.
Maintenance
Asia and Oceania
In Australia, lighthouses are conducted by the Australian Maritime Safety Authority
Australian Maritime Safety Authority (AMSA) is an Australian statutory authority responsible for the regulation and safety oversight of Australia's shipping fleet and management of Australia's international maritime obligations. The authority ...
.
In India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, lighthouses are maintained by the Directorate General of Lighthouses and Lightships, an office of the Ministry of Ports, Shipping and Waterways
The Ministry of Ports, Shipping and Waterways is the Indian ministry responsible for formulation and administration of the rules, regulations and laws relating to ports, shipping and waterways. The minister is Sarbananda Sonowal.
Ministers
...
.
Europe
The Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
built a number of automated lighthouses powered by radioisotope thermoelectric generator
A radioisotope thermoelectric generator (RTG, RITEG), sometimes referred to as a radioisotope power system (RPS), is a type of nuclear battery that uses an array of thermocouples to convert the heat released by the decay of a suitable radioacti ...
s in remote locations. They operated for long periods without external support with great reliability. However numerous installations deteriorated, were stolen, or vandalized. Some cannot be found due to poor record-keeping.
Both the United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...
and the Republic of Ireland
Ireland ( ga, Éire ), also known as the Republic of Ireland (), is a country in north-western Europe consisting of 26 of the 32 Counties of Ireland, counties of the island of Ireland. The capital and largest city is Dublin, on the eastern ...
together have three bodies: lighthouses around the coasts of England and Wales are looked after by Trinity House
"Three In One"
, formation =
, founding_location = Deptford, London, England
, status = Royal Charter corporation and registered charity
, purpose = Maintenance of lighthouses, buoys and beacons
, he ...
, those around Scotland and the Isle of Man by the Northern Lighthouse Board
The Northern Lighthouse Board (NLB) is the general lighthouse authority for Scotland and the Isle of Man. It is a non-departmental public body responsible for marine navigation aids around coastal areas.
History
The NLB was formed by Act of P ...
and those around Ireland by the Commissioners of Irish Lights
The Commissioners of Irish Lights ( ga, Coimisinéirí Soilse na hÉireann), often shortened to Irish Lights or CIL, is the body that serves as the general lighthouse authority for Northern Ireland and the Republic of Ireland and their adjacen ...
.
North America
In Canada, lighthouses are managed by the Canadian Coast Guard
The Canadian Coast Guard (CCG; french: links=no, Garde côtière canadienne, GCC) is the coast guard of Canada. Formed in 1962, the coast guard is tasked with marine search and rescue (SAR), communication, navigation, and transportation issues ...
.
In the United States, lighthouses are maintained by the United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mu ...
.
Preservation
As lighthouses became less essential to navigation, many of their historic structures faced demolition or neglect. In the United States, the National Historic Lighthouse Preservation Act of 2000 provides for the transfer of lighthouse structures to local governments and private non-profit groups, while the USCG continues to maintain the lamps and lenses. In Canada, the Nova Scotia Lighthouse Preservation Society {{refimprove, date=November 2022
The Nova Scotia Lighthouse Preservation Society (NSLPS) is a non profit charitable organization that works to save lighthouses in the province of Nova Scotia, Canada. It is the largest and oldest lighthouse heritag ...
won heritage status for Sambro Island Lighthouse
Sambro Island Lighthouse is a landfall lighthouse located at the entrance to Halifax Harbour, Nova Scotia, on an island near the community of Sambro in the Halifax Regional Municipality. It is the oldest surviving lighthouse in North America an ...
, and sponsored the Heritage Lighthouse Protection Act to change Canadian federal laws to protect lighthouses.
Many groups formed to restore and save lighthouses around the world, including the World Lighthouse Society
In its most general sense, the term "world" refers to the totality of entities, to the whole of reality or to everything that is. The nature of the world has been conceptualized differently in different fields. Some conceptions see the worl ...
and the United States Lighthouse Society
The United States Lighthouse Society is a non-profit organization dedicated to aiding in the restoration of American lighthouses and educating the public about their history. With four chapters, and more than a dozen affiliates, it is one of the ...
, as well as the Amateur Radio Lighthouse Society
Founded in 2000 by Jim Weidner, K2JXW, the Amateur Radio Lighthouse Society (ARLHS) is devoted to maritime communications, amateur radio, lighthouses, and lightships. Its members travel to lighthouses around the world where they operate amate ...
, which sends amateur radio operators to publicize the preservation of remote lighthouses throughout the world.
See also
*Crib lighthouse
A Crib lighthouse is a type of lighthouse whose structure rests on a concrete or masonry foundation supported with wooden beams. The name "crib" refers to the wooden crib pier style of construction which was used as a foundation for lighthouses. ...
*Day beacon
A day beacon (sometimes "daybeacon") is an unlighted nautical sea mark. A signboard identifying it is called a day mark. Day beacons typically mark channels whose key points are marked by lighted buoys. They may also mark smaller navigable rout ...
* Foghorn
* Fresnel lens sizes (orders)
* Lens lantern
*Lighthouse keeper
A lighthouse keeper or lightkeeper is a person responsible for tending and caring for a lighthouse, particularly the light and lens in the days when oil lamps and clockwork mechanisms were used. Lighthouse keepers were sometimes referred to as ...
*Lists of lighthouses
This article contains links to lists of lighthouses around the world. According to ''Lighthouse Directory'', there are more than 18,600 lighthouses worldwide.
Africa
*''Note: Click on the country or place name of your choice in the table bel ...
*Lists of lightvessels
This article lists lightvessels around the world. Most surviving light vessels reside in the United Kingdom and the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is ...
* Pharology
* Pintsch gas
*Sea mark
A sea mark, also seamark and navigation mark, is a form of aid to navigation and pilotage that identifies the approximate position of a maritime channel, hazard, or administrative area to allow boats, ships, and seaplanes to navigate safely.
T ...
References
;Notes
;Bibliography
* Bathurst, Bella. ''The lighthouse Stevensons''. New York: Perennial, 2000.
* Beaver, Patrick. ''A History of Lighthouses''. London: Peter Davies Ltd, 1971. .
* Crompton, Samuel, W; Rhein, Michael, J. ''The Ultimate Book of Lighthouses''. San Diego, CA: Thunder Bay Press, 2002. .
* Jones, Ray; Roberts, Bruce. ''American Lighthouses''. Globe Pequot, 1998. 1st ed. .
* Stevenson, D. Alan. ''The world's lighthouses before 1820''. London: Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print books ...
, 1959.
;Further reading
* Noble, Dennis. ''Lighthouses & Keepers: U. S. Lighthouse Service and Its Legacy''. Annapolis: U.S. Naval Institute Press, 1997. .
* Putnam, George R. ''Lighthouses and Lightships of the United States''. Boston: Houghton Mifflin Co., 1933.
* Rawlings, William. 2021. ''Lighthouses of the Georgia Coast.'' Macon, GA: Mercer University Press.
* Weiss, George. ''The Lighthouse Service, Its History, Activities and Organization''. Baltimore: Johns Hopkins Press, 1926.
External links
United States Lighthouses
"Lighthouses Of Strange Designs, December 1930, Popular Science
* Research tool with details of over 14,700 lighthouses and navigation lights around the world with photos and links.
*Pharology Website: http://www.pharology.eu . Reference source for the history and development of lighthouses of the world.
* Includes 54 diagrams and photographs.
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