Editing Lighthouse (section)

==History==
{{Main|History of lighthouses}}

===Ancient lighthouses===
[[File:Torre de Hércules 2023.jpg|thumb|upright=0.9|The [[Tower of Hercules]] lighthouse in northwest Spain]]
Before the development of clearly defined [[port]]s, mariners were guided by fires built on hilltops. Since elevating the fire would improve visibility, placing the fire on a platform became a practice that led to the development of the lighthouse.<ref>Trethewey, K. R.:Ancient Lighthouses, Jazz-Fusion Books (2018), 326pp. {{ISBN|978-0-99265-736-9}}</ref> In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for [[reef]]s and [[promontory|promontories]], unlike many modern lighthouses. The most famous lighthouse structure from antiquity was the [[Lighthouse of Alexandria|Pharos]] of [[Alexandria]], [[Egypt]], which collapsed following a series of earthquakes between 956 and 1323.

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 Antica (archaeological site)|Ostia]]. Coins from Alexandria, Ostia, and [[Latakia|Laodicea in Syria]] 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 [[Atlantic Ocean|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 was gradually changed from indicating ports to the providing of a visible warning against shipping hazards, such as rocks or reefs.

[[File:Edystone Winstanley lighthouse Smeaton 1813.jpg|thumb|Original [[Eddystone Lighthouse#Winstanley's Lighthouse|Winstanley lighthouse]], Eddystone Rock, by Jaaziell Johnston, 1813.]]
The [[Eddystone Rocks]] were a major shipwreck hazard for mariners sailing through the [[English Channel]].<ref>{{citation|first=Samuel|last=Smiles|title=The Lives of the Engineers|year=1861|volume=2|page=16|url=https://archive.org/stream/livesofengineers02smil#page/16/mode/2up}}</ref> The [[Eddystone Lighthouse#Winstanley's lighthouse|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.<ref>{{Cite web|url=https://www.britannica.com/EBchecked/topic/340721/lighthouse/72148/The-beginning-of-the-modern-era|title=lighthouse|access-date=17 December 2012}}</ref>

The [[civil engineer]] [[John Smeaton]] rebuilt the [[Smeaton's Tower|lighthouse]] from 1756 to 1759;<ref name="MAJ">Majdalany, Fred: ''The Eddystone Light''. 1960</ref> 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 joint]]s and marble [[dowels]].<ref name="TRI">{{cite web|url=http://www.trinityhouse.co.uk/interactive/gallery/eddystone.html |title=Eddystone – Gallery |publisher=Trinity House |access-date=3 May 2010 |url-status=dead |archive-url=https://web.archive.org/web/20060909043743/http://www.trinityhouse.co.uk/interactive/gallery/eddystone.html |archive-date=9 September 2006 }}</ref> 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.<ref>{{cite book|title=Minutes of proceedings of the Institution of Civil Engineers|chapter=Note on the Eddystone Lighthouse|author=Douglass, James Nicholas|location=London|publisher=Institution of Civil Engineers|year=1878|volume=53, part 3|pages=247–248|chapter-url=https://books.google.com/books?id=cx4AAAAAMAAJ&pg=PA247}}</ref>

[[File:Smeaton's Lighthouse00.jpg|thumb|right|upright=1.1|[[John Smeaton]]'s rebuilt version of the [[Eddystone Lighthouse]], 1759. This represented a great step forward in lighthouse design.]]
One such influence was [[Robert Stevenson (civil engineer)|Robert Stevenson]], himself a seminal figure in the development of lighthouse design and construction.<ref name="NLB">{{cite web|url=http://www.nlb.org.uk/HistoricalInformation/StevensonEngineers/Robert-Stevenson/|title=NLB – Robert Stevenson|access-date=28 January 2013}}</ref> His greatest achievement was the construction of the [[Bell Rock Lighthouse]] in 1810, one of the most impressive feats of engineering of the age.{{Citation needed|date=May 2021}} 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.<ref>{{citation|title=John Rennie, 1761–1821: The Life and Work of a Great Engineer|first=Cyril Thomas Goodman|last=Boucher|page=61|year=1963|url=https://books.google.com/books?id=1wu8AAAAIAAJ&pg=PA59}}</ref> Stevenson worked for the [[Northern Lighthouse Board]] for nearly fifty years<ref name="NLB" /> 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]]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.
[[File:Marjaniemen majakka.jpg|thumb|upright=1.1|[[Marjaniemi Lighthouse]], the 19th-century lighthouse in the [[Hailuoto]] island, neighbouring municipality of [[Oulu]], [[Finland]]]]
[[Alexander Mitchell (engineer)|Alexander Mitchell]] designed the first [[screw-pile lighthouse]] – his lighthouse was built on piles that were [[screw]]ed 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.<ref name=Tomlinson>{{cite book|title=Tomlinson's Cyclopaedia of Useful Arts|year=1852–1854|publisher=Virtue & Co.|location=London|page=[https://archive.org/details/cyclopdiaofuse02tomlrich/page/177 177]|editor=Tomlinson|url=https://archive.org/details/cyclopdiaofuse02tomlrich|quote=[Maplin Sands] was not, however, the first screw-pile lighthouse actually erected, for during the long preparation process which was carried on at Maplin Sands, a structure of the same principle had been begun and completed at Port Fleetwood...}}</ref> Although its construction began later, the [[Wyre Light (Fleetwood)|Wyre Light]] in Fleetwood, Lancashire, was the first to be lit (in 1840).<ref name=Tomlinson />

===Lighting improvements===
Until 1782 the source of illumination had generally been wood pyres or burning coal. The [[Argand lamp]], invented in 1782 by the Swiss scientist [[Aimé Argand]] revolutionized lighthouse illumination with its steady smokeless flame. Early models used ground glass which was sometimes tinted around the wick. Later models used a [[Gas mantle|mantle]] of [[thorium dioxide]] suspended over the flame, creating a bright, steady light.<ref>{{cite web|url=http://www.johnmoncrieff.co.uk/shop-2/products.php?cat=32|title=Lamp Glass Replacement Glass Lamp Shades, Oil Lamp Shades, Oil Lamp Chimneys, Oil Lamp Spares|url-status=dead|archive-url=https://web.archive.org/web/20140106160403/http://www.johnmoncrieff.co.uk/shop-2/products.php?cat=32|archive-date=6 January 2014}}</ref> The Argand lamp used [[whale oil]], [[colza]], [[olive oil]]<ref>"Lamp." ''Encyclopædia Britannica: or, a dictionary of Arts, Science, and Miscellaneous Literature.''  6th ed. 1823 [https://books.google.com/books?id=T8wnAAAAMAAJ&dq=%22argand+lamp%22+%22olive+oil%22&pg=PA505 Web.] 5 December 2011</ref> or other [[vegetable oil]] as fuel, supplied by a [[gravity feed]] from a reservoir mounted above the burner. The lamp was first produced by [[Matthew Boulton]], in partnership with Argand, in 1784, and became the standard for lighthouses for over a century.<ref>{{cite web|url=https://www.britannica.com/technology/lighthouse/Modern-lighthouses#ref668277|title=Modern Lighthouses|website=Encyclopædia Britannica|access-date=4 August 2021}}</ref>

[[South Foreland Lighthouse]] was the first tower to successfully use an electric light in 1875. The lighthouse's carbon [[arc lamp]]s were powered by a steam-driven [[magneto (generator)|magneto]].<ref>{{cite book |last=Baird |first=Spencer Fullerton|title=Annual record of science and industry |publisher=Harper & Brothers|location=New York|year=1876|pages=460}}</ref> [[John Richardson Wigham]] was the first to develop a system for [[coal gas|gas]] 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.<ref name=cil>{{cite journal| title=John Richardson Wigham 1829–1906 | url=http://www.commissionersofirishlights.com/media/35546/Beam_2006.PDF#page=23 | publisher=Commissioners of Irish Lights | journal=BEAM | volume=35 | date=2006–2007 | pages=21–22|archive-url=https://web.archive.org/web/20120312014229/http://www.commissionersofirishlights.com/media/35546/Beam_2006.PDF|archive-date=12 March 2012}}</ref>
[[File:Sumburgh Lighthouse Lamp.jpg|thumb|An {{convert|85|mm|in}} Chance Brothers ''Incandescent Petroleum Vapour Installation'' which produced the light for the [[Sumburgh Head]] lighthouse until 1976. <!-- All text in this caption after this comment should be put somewhere in the article body instead. -->The lamp (made in approx. 1914) burned vaporized [[kerosene]] (paraffin); the vaporizer was heated by a [[denatured alcohol]] (methylated spirit) burner to light. When lit, some of the vaporised fuel was diverted to a [[Bunsen burner]] to keep the vaporizer warm and the fuel in vapor form. The fuel was forced up to the lamp by air; the keepers had to pump the air container up every hour or so, pressurizing the paraffin container to force the fuel to the lamp. The "white sock" pictured is  an unburnt mantle on which the vapor burned.]]
The vaporized oil burner was invented in 1901 by [[Arthur Kitson]], and improved by David Hood at [[Trinity House]]. 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.{{cn|date=December 2024}} The use of gas as illuminant became widely available with the invention of the [[Dalén light]] by Swedish engineer [[Gustaf Dalén]]. He used [[Agamassan]] (Aga), a [[Substrate (materials science)|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.{{Citation needed paragraph|date=May 2021}} The technology was the predominant light source in lighthouses from the 1900s to the 1960s, when electric lighting had become dominant.<ref>{{cite web|url=http://www.aga.com/web/web2000/com/WPPcom.nsf/pages/History_SunValve|title=The Linde Group - Gases Engineering Healthcare -|access-date=6 April 2017|archive-url=https://web.archive.org/web/20151018000926/http://www.aga.com/web/web2000/com/WPPcom.nsf/pages/History_SunValve|archive-date=18 October 2015|url-status=dead}}</ref>

===Optical systems===
[[File:Fresnel lighthouse lens diagram.png|thumb|right|Diagram depicting how a spherical [[Fresnel lens]] collimates light]]
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 (privateer)|William Hutchinson]] developed the first practical optical system in 1777, known as a [[catoptrics|catoptric]] system.<ref>{{cite web | title=Illumination, Refraction, Fresnel Lens | website=Encyclopedia Britannica | date=9 October 1998 | url=https://www.britannica.com/technology/lighthouse/Optical-equipment#ref593050 | access-date=2 June 2024}}</ref> This rudimentary system effectively collimated the emitted light into a concentrated beam, thereby greatly increasing the light's visibility.<ref>{{cite encyclopedia|url=https://www.britannica.com/EBchecked/topic/340721/lighthouse/72152/Oil-lamps|title=Lighthouse|encyclopedia=Encyclopædia Britannica|access-date=6 January 2014}}</ref> 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]] developed the multi-part [[Fresnel lens]] for use in lighthouses. His design allowed for the construction of lenses of large [[aperture]] 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]] at the mouth of the [[Gironde estuary]]; its light could be seen from more than {{convert|20|mi|km}} out.<ref>Watson, Bruce. "Science Makes a Better Lighthouse Lens." ''Smithsonian''. August 1999 v30 i5 p30.
produced in ''Biography Resource Center''. Farmington Hills, Mich.: Thomson Gale. 2005.</ref> 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 changer]]s began to make [[lighthouse keeper]]s obsolete. For many years, lighthouses still had keepers, partly because lighthouse keepers could serve as a [[emergency service|rescue service]], if necessary. Improvements in maritime navigation and safety, such [[Global Positioning System]] (GPS), led to the phasing out of non-automated lighthouses across the world.<ref>{{cite web|url=http://www.nps.gov/history/maritime/keep/keep19th.htm|title=Maritime Heritage Program - National Park Service|access-date=6 April 2017}}</ref> Although several closed due to safety concerns, Canada still maintains 49 staffed lighthouses, split roughly evenly across east and west coasts.<ref>{{Cite web |last=Government of Canada |first=Fisheries and Oceans Canada |date=2017-09-08 |title=Lighthouses in Canada |url=https://www.dfo-mpo.gc.ca/otw-am/lighthouses-phares/canada-eng.html |access-date=2024-11-14 |website=www.dfo-mpo.gc.ca}}</ref><ref>{{cite web|url=http://www.fogwhistle.ca/bclights|title=Lighthouses of British Columbia|access-date=3 November 2011|archive-url=https://web.archive.org/web/20111103070010/http://www.fogwhistle.ca/bclights/|archive-date=3 November 2011|url-status=dead}}</ref><ref>{{Cite news |date=31 July 2024 |title=Staffing at 2 B.C. lighthouses to end following safety concerns |url=https://www.cbc.ca/news/canada/british-columbia/lighthouses-vancouver-island-coast-not-staffed-1.7281513 |access-date=13 November 2024 |work=[[Canadian Broadcasting Corporation|CBC]]}}</ref>

The remaining modern lighthouses are usually illuminated by a single stationary flashing light powered by solar-charged batteries and mounted on a steel skeleton tower.<ref name="Crompton"/> Where the power requirement is too great for solar power alone, ''cycle charging'' of the battery by a Diesel generator is provided. The generator only comes into use when the battery needs charging, saving fuel and increasing periods between maintenance.<ref>{{cite book |last1=Nicholson |first1=Christopher |title=Rock lighthouses of Britain: The end of an era? |date=2000 |publisher=Whittles |location=Caithness, Scotland |isbn=978-1870325417 |page=126}}</ref>

===Famous lighthouse builders===
[[John Smeaton]] is noteworthy for having designed the third and most famous [[Eddystone Lighthouse]], but some builders are well known for their work in building multiple lighthouses. The Stevenson family ([[Robert Stevenson (civil engineer)|Robert]], [[Alan Stevenson|Alan]], [[David Stevenson (engineer)|David]], [[Thomas Stevenson|Thomas]], [[David Alan Stevenson|David Alan]], and [[Charles Alexander Stevenson|Charles]]) made lighthouse building a three-generation profession in Scotland. 
[[Richard Henry Brunton]] designed and built 26 [[Template:Lighthouses of Japan|Japanese lighthouses]] in [[Meiji (era)|Meiji Era]] Japan, which became known as Brunton's "children".<ref>{{cite news | url=https://www.icevirtuallibrary.com/doi/abs/10.1680/imotp.1901.18577 |title=Obituary - Richard Henry Brunton | work=Minutes of the Proceedings of the Institution of Civil Engineers |volume=145 |issue=1901 |year=1901 |pages=340–341 |doi=10.1680/imotp.1901.18577 |access-date=20 April 2018}}</ref> Blind Irishman [[Alexander Mitchell (engineer)|Alexander Mitchell]] invented and built a number of screw-pile lighthouses. Englishman [[James Nicholas Douglass|James Douglass]] was knighted for his work on the fourth Eddystone Lighthouse.<ref>{{cite DNBSupp|title=Douglass, James Nicholas |first=Thomas Hudson|last=Beare}}</ref>

[[United States Army Corps of Engineers]] Lieutenant [[George Meade]] built numerous lighthouses along the Atlantic and Gulf coasts before gaining wider fame as the winning general at the [[Battle of Gettysburg]].  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]].<ref>{{cite web|url=http://www.nps.gov/history/maritime/keep/architect.htm|title=Maritime Heritage Program - National Park Service|access-date=6 April 2017}}</ref>

French merchant navy officer [[Marius Michel Pasha]] built almost a hundred lighthouses along the coasts of the [[Ottoman Empire]] in a period of twenty years after the [[Crimean War]] (1853–1856).<ref name="hnet">{{cite web |url=http://www.h-net.org/reviews/showrev.php?id=11049 |publisher=Humanities and Social Sciences Net Online |title=Review of Thobie, Jacques, L'administration generale des phares de l'Empire ottoman et la societe Collas et Michel, 1860–1960. H-Mediterranean, H-Net Reviews. January, 2006 | author=Guigueno, Vincent |date=January 2006 |access-date=20 September 2010}}</ref>