Editing Eddystone Lighthouse (section)

== Douglass's lighthouse ==
[[File:Eddystone Lighthouse, Plymouth, England-LCCN2002708052.jpg|thumb|right|alt=Eddystone lighthouse in the late 19th century.|Late 19th-century colourised photograph of Douglass's lighthouse (with the remaining lower part of the old lighthouse alongside).]]
The current, fourth lighthouse was designed by [[James Nicholas Douglass|James Douglass]] (using [[Robert Stevenson (civil engineer)|Robert Stevenson's]] developments of Smeaton's techniques).{{citation needed|date=March 2021}} This lighthouse is still in use.

===Design and building===
[[File:Eddystone-Douglass.gif|thumb|left|150px|Original drawing of 4th Eddystone Lighthouse.]]
By July 1878 the new site, on the South Rock was being prepared during the 3½ hours between [[ebb tide|ebb]] and [[flood tide]]; the [[foundation stone]] was laid on 19 August the following year by [[Alfred, Duke of Saxe-Coburg and Gotha|The Duke of Edinburgh]], Master of Trinity House.<ref name="EB1902" /> The supply ship ''Hercules'' was based at [[Oreston]], now a suburb of [[Plymouth]]; stone was prepared at the Oreston yard and supplied from the works of Messrs Shearer, Smith and Co of [[Wadebridge]].<ref>{{cite news|title=Commencement and Progress of the Eddystone|work=[[The Cornishman (newspaper)|The Cornishman]]|issue=40|date=17 April 1879|page=6}}</ref><ref>{{cite news|title=The New Eddystone Lighthouse|work=The Cornishman|issue=49|date=19 June 1879|page=3}}</ref> The tower, which is {{convert|49|m|ft}} high, contains a total of 62,133 cubic feet of granite, weighing 4,668 tons.<ref name="EB1902" /> The last stone was laid on 1 June 1881 and the light was first lit on 18 May 1882.

The lighthouse was topped by a larger than usual lantern storey, {{convert|16|ft|6|in|abbr=on}} high and {{convert|14|ft|abbr=on}} wide;<ref name="PriceEdwards1882" /> the lantern was painted red.<ref name="King1886">{{cite book |last1=King |first1=John W. |title=The Channel Pilot (Part 1) |date=1886 |publisher=The Hydrographic Office, Admiralty |location=London |page=83}}</ref> It contained a six-sided biform (i.e. two-tier) rotating optic of the [[First order Fresnel lens|first-order]], {{convert|12|ft|6|in|abbr=on}} high and weighing over seven tons.<ref name="Palmer2005" /><ref>{{Cite web|url=https://www.alamy.com/stock-photo-the-eddystone-lighthouse-built-on-the-stone-13-miles-south-east-of-57290353.html|title=The Eddystone lighthouse built on the Stone 13 miles South-east of Polperro, Cornwall, England. This is the fifth Eddystone lighthouse, designed by James Douglas, engineer to Trinity House, built between 1878 and 1892. Inside the lantern showing two drums of bull's-eye lenses. Each drum was 6 ft (1.828 metres) high. The keeper is winding up the revolving mechanism. Engraving from 'The Strand Magazine' (London, 1892 Stock Photo - Alamy|first=Alamy|last=Limited|website=www.alamy.com|accessdate=29 July 2024}}</ref> Each of the six sides of the optic was divided into two [[Fresnel lens]] panels, which provided the light's characteristic of two flashes every thirty seconds.<ref name="EB">[[Wikisource:Page:EB1911 – Volume 16.djvu/672|Encyclopaedia Britannica, 1911 edition, vol. 16, p. 650.]]</ref> The optic was manufactured by [[Chance Brothers]] of [[Smethwick]] and designed by their chief engineer [[John Hopkinson]] FRS. At the time the Eddystone's extra-tall ({{convert|6|ft|3|in|abbr=on|adj=on}}) lenses were the largest in existence;<ref name="TagHRLenses">{{cite web |last1=Tag |first1=Thomas |title=Hyper-Radial Lenses |url=https://uslhs.org/hyper-radial-lenses |website=United States Lighthouse Society |access-date=25 January 2020 |archive-date=29 October 2020 |archive-url=https://web.archive.org/web/20201029111141/https://uslhs.org/hyper-radial-lenses |url-status=dead }}</ref> their superior height was achieved through the use of extra-dense [[flint glass]] in the upper and lower portions of each panel.<ref>{{cite book |last1=Chance |first1=James Frederick |title=A History of the Firm of Chance Brothers & Co. |date=2018 |publisher=Society of Glass Technology |location=Sheffield, UK |page=178}}</ref>

The light had a range of {{convert|17|nmi}}.<ref name="King1886" /> Illumination was provided by a pair of Douglass-designed six-wick concentric [[Argand lamp|oil burners]] (one for each tier of the optic).<ref>{{Cite web|url=https://www.alamy.com/stock-photo-the-eddystone-lighthouse-built-on-the-stone-13-miles-south-east-of-57290360.html|title=The Eddystone lighthouse built on the Stone 13 miles South-east of Polperro, Cornwall, England. This is the fifth Eddystone lighthouse, designed by James Douglas, engineer to Trinity House, built between 1878 and 1892. Lighting the oil lamp inside the rim of the bull's-eye lenses. Engraving from 'The Strand Magazine' (London, 1892 Stock Photo - Alamy|first=Alamy|last=Limited|website=www.alamy.com|accessdate=29 July 2024}}</ref> This was said to represent 'the first practical application of superposed lenses of the first order with oil as the illuminating material'.<ref name="Douglass1883" /><ref group=note>There were in fact several optics with two or more tiers of first-order lenses already in use in lighthouses around the coast of Ireland (engineered by Douglass's great rival [[John Richardson Wigham]]), but these were lit by gas.</ref> On clear nights, only the lamp in the lower tier of lenses was lit (producing a light of 37,000 candlepower); in poor visibility, however (judged by whether the [[Plymouth Breakwater|Plymouth Breakwater light]] was visible), both lamps were used at full power, to provide a 159,600 candlepower light.<ref name="Palmer2005" /> Eighteen cisterns in the lower part of the tower were used to store up to 2,660 tons (nine months' worth) of [[colza oil]] to fuel the lamps.<ref name="Adams1891">{{cite book |last1=Davenport Adams |first1=W. H. |title=The Story of our Lighthouses and Lightships: Descriptive and Historical |date=1891 |publisher=Thomas Nelson & Sons |location=London, Edinburgh & New York |pages=111–116 |url=https://pharology.eu/resources/books/23)%20The%20Story%20of%20Our%20Lighthouses%20and%20Lightships%20-%20descriptive%20and%20historical%20(1891).pdf |access-date=27 February 2019}}</ref>

In addition to the main light a fixed white light was shone from a room on the eighth storey of the tower (using a pair of [[Argand lamp]]s and [[Parabolic reflector|reflectors]]) in the direction of the hazardous [[Hand Deeps]].<ref>{{Cite web|url=https://www.alamy.com/stock-photo-the-lower-light-room-in-the-eddystone-lighthouse-built-on-the-stone-57290336.html|title=The lower-light room in the Eddystone lighthouse built on the Stone 13 miles South-east of Polperro, Cornwall, England, showing the twin Argand burners and reflectors (detail inset) which lighted the Hand Deeps rocks about three miles away. This is the fifth Eddystone lighthouse, designed by James Douglas, engineer to Trinity House, built between 1878 and 1892. Engraving from 'The Strand Magazine' (London, 1892 Stock Photo - Alamy|first=Alamy|last=Limited|website=www.alamy.com|accessdate=29 July 2024}}</ref> The lighthouse was also provided with a pair of large bells, each weighing two tons, by [[Gillett, Bland & Co.]], which were suspended from either side of the lantern gallery to serve as a [[fog signal]]; they sounded (to match the [[light characteristic]] of the lighthouse) twice every thirty seconds in foggy weather, and were struck by the same clockwork mechanism that drove the rotation of the lenses. The mechanism required winding every hour (or every forty minutes, when the bells were in use), 'the weight to be lifted being equal to one ton';<ref name="PriceEdwards1882">{{cite book |last1=Price Edwards |first1=E. |title=The Eddystone Lighthouses (new and Old) |date=1882 |publisher=Simpkin, Marshall |location=London |pages=13–28}}</ref> shortly after opening, the lighthouse was equipped with a 0.5 h.p. [[caloric engine]],<ref name="EB1902">{{cite journal |title=Lighthouses |journal=Encyclopaedia Britannica, 10th Edition |date=1902 |volume=30 |page=252 |url=https://digital.nls.uk/encyclopaedia-britannica/archive/193470564# |access-date=19 February 2020}}</ref> designed 'for relieving the keepers of the excessive strain of driving the machine when both illuminating apparatus and fog bell are in use'.<ref name="Douglass1883">{{cite journal |last1=Douglass |first1=William Tregarthen |title=The New Eddystone Lighthouse |journal=Minutes of Proceedings of the Institution of Civil Engineers |date=27 November 1883 |volume=LXXV |issue=1960 |pages=20–36}}</ref>

===Later modifications===
[[File:EB1911 - Lighthouse - Fig. 57.—Eddystone Lighthouse.jpg|thumb|right|alt=Douglass's Eddystone lighthouse.|Photograph, c.1911, of Douglass's lighthouse (after removal of the bells).]]
In 1894 an explosive fog signal device was installed on the gallery of lighthouse; the fog bells were briefly retained as a standby provision, but then removed.<ref name="Renton2001" /> In 1904 the lamps were replaced with incandescent oil vapour burners.<ref name="EB" /> Following the invention of the mercury bath system (allowing a lighthouse optic to revolve in a trough of mercury rather than on rollers) the Eddystone lens pedestal was duly upgraded and the drive mechanism replaced.<ref name="Palmer2005">{{cite book |last1=Palmer |first1=Mike |title=Eddystone: The Finger of Light |date=2005 |publisher=Seafarer Books |location=Woodbridge, Suffolk |page=123}}</ref> Later, beginning in 1959, the light was electrified: the new light source was a 1,250W [[incandescent lamp]], powered by a diesel generator (three of which were installed in a lower store room).<ref name="Majdalany1960" /> In place of the old lenses a new, smaller (fourth-order) [[AGA AB|AGA]] 'bi-valve' optic was installed, which flashed at the faster rate of twice every ten seconds. The old optic was removed and donated to [[Southampton Maritime Museum]]<ref>{{Cite web|url=https://www.dailyecho.co.uk/heritage/14171096.the-weird-attractions-of-southamptons-royal-pier/|title=The weird attractions of Southampton's Royal Pier|date=29 December 2015|website=Daily Echo|accessdate=29 July 2024}}</ref> (it was exhibited on the [[Royal Pier, Southampton|Royal Pier]] in the 1970s, but later removed to a council yard where it was destroyed by vandals).<ref name="Palmer2005" /> As part of the programme of modernisation, the lighthouse was given a '[[Train horn#Leslie Controls, Inc.|SuperTyfon]]' fog signal, with compressors powered from the diesel generators.<ref name = "Renton2001">{{cite book |last1=Renton |first1=Alan |title=Lost Sounds: The Story of Coast Fog Signals |date=2001 |publisher=Whittles |location=Caithness, Scotland}}</ref>

[[File:Phare-d-Eddystone-Rocks.jpg|thumb|left|The lighthouse in 2005 (with helipad and solar panels) alongside the stub of Smeaton's Tower.]]
The lighthouse was automated in 1982, the first [[Trinity House]] 'Rock' (or offshore) lighthouse to be converted. Two years earlier the tower had been changed by construction of a [[helipad]] above the lantern, to allow maintenance crews access;<ref name=thinfo2>{{cite web | title = Eddystone Lighthouse | url = http://www.trinityhouse.co.uk/interactive/gallery/eddystone.html | publisher = Trinity House | access-date =30 December 2015 }}</ref> the helipad has a weight limit of 3600&nbsp;kg (3½ tons). As part of the automation of the lighthouse a new electric fog signal was installed and a metal halide [[discharge lamp]] replaced the incandescent light bulb formerly in use. The light and other systems were monitored remotely, initially by Trinity House staff at the nearby [[Penlee Point, Rame|Penlee Point]] [[fog signal station]].<ref name="NS1983">{{cite journal |last1=Auld |first1=Jack |title=Automation relieves the Eddystone keeper |journal=New Scientist |date=21 July 1983 |volume=99 |issue=1367 |page=213}}</ref> Since 1999 the lighthouse has run on solar power.<ref name="WoodmanWilson">{{cite book |last1=Woodman |first1=Richard |last2=Wilson |first2=Jane |title=The Lighthouses of Trinity House |date=2002 |publisher=Thomas Reed |location=Bradford-on-Avon, Wilts. |page=179}}</ref>

===Present day===
The tower is {{convert|49|m|ft}} high, and [[Light characteristic|its white light flashes twice every 10&nbsp;seconds]]. The light is visible to {{convert|22|nmi|km}}, and is supplemented by a [[foghorn]] of 3 blasts every 62&nbsp;seconds.<ref name="thinfo" /> A subsidiary red [[sector light]] shines from a window in the tower to highlight the [[Hand Deeps]] hazard to the west-northwest. The lighthouse is now monitored and controlled from the Trinity House Operations Control Centre at Harwich in Essex.
{{Clear}}