A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways.
81-676: Lowestoft Lighthouse is a lighthouse operated by Trinity House located to the north of the centre of Lowestoft in the English county of Suffolk . It stands on the North Sea coast close to Ness Point , the most easterly point in the United Kingdom. It acts as a warning light for shipping passing along the east coast and is the most easterly lighthouse in the UK. The original lighthouses at Lowestoft, which were established in 1609, were
162-432: A lingual pipe) is an organ pipe that is sounded by a vibrating brass strip known as a reed . Air under pressure (referred to as wind ) is directed towards the reed, which vibrates at a specific pitch . This is in contrast to flue pipes , which contain no moving parts and produce sound solely through the vibration of air molecules . Reed pipes are common components of pipe organs . Reed pipes include all stops of
243-402: A 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. Although several closed due to safety concerns, Canada still maintains 49 staffed lighthouses, split roughly evenly across east and west coasts. The remaining modern lighthouses are usually illuminated by
324-405: A 90-degree angle at the top. In places where a full-length resonator will not fit, a technique called mitering is used, wherein organ pipes are created so that instead of standing straight up, they appear to make a loop in the middle of the resonator. This is done by joining several small pieces of metal together. As wind enters the boot, it travels over the reed, causing it to vibrate against
405-640: A Diesel generator for backup. Many Fresnel lens installations have been replaced by rotating aerobeacons , which require less maintenance.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 (LED) panels. LED lights, which use less energy and are easier to maintain, had come into widespread use by 2020. In
486-406: A French "double-block") in which the reed assembly is set has an effect on the sound. Scaling is important when determining the final tone color of a reed pipe, though it is not of primary importance as it is in flue pipe construction. This is because reed pipe resonators simply reinforce certain partials of the sound wave; the air column inside the resonator is not the primary vibrator. The shape of
567-437: A cluster of seven Welsbach mantle burners being installed within the optic. The burners were switched on and off by clockwork, to preserve the occulting characteristic (the gas being cut off for three seconds every half-minute). The red and white sectors had a range of 13 and 14.5 nautical miles respectively. The High Lighthouse was repaired and improved in 1825, and also in 1840 (when a pair of houses were built alongside for
648-436: A filament source. 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 , Queensland , was replaced by a conventional light after four years, because
729-457: 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
810-414: A horizontal plane, and horizontally the light is focused into one or a few directions at a time, with the light beam 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 . This concentration of light is accomplished with a rotating lens assembly. In early lighthouses, the light source
891-427: A more powerful hyperradiant Fresnel lens manufactured by the firm of Chance Brothers . 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
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#1732780858740972-538: A navigator with a line of position called a range in North America and a transit 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 in the United Kingdom. The closer light
1053-521: A number of screw-pile lighthouses. Englishman James Douglass was knighted for his work on the fourth Eddystone Lighthouse. 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
1134-402: 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. Before modern strobe lights , lenses were used to concentrate the light from a continuous source. Vertical light rays of the lamp are redirected into
1215-548: A range of 23 nautical miles (43 km; 26 mi), was automated in 1975. The first two lighthouses in Lowestoft were built in 1609, on the foreshore warn shipping of dangerous sandbanks around the coast. Both were lit originally by candles. By lining up the two lights, vessels could navigate the Stamford Channel which no longer exists. They were rebuilt in 1628 and again in 1676. It was at this time that one light
1296-411: 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. South Foreland Lighthouse 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 . John Richardson Wigham was the first to develop
1377-415: A single stationary flashing light powered by solar-charged batteries and mounted on a steel skeleton tower. 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. John Smeaton is noteworthy for having designed
1458-477: A system for 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. 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
1539-444: A visible range of 11 nautical miles (20 km; 13 mi). It was first lit on 15 January 1867 and shone red out to sea but with two white sectors indicating the safe inshore water (or Roads ) to the north and the south. A fog bell was also provided, which sounded three times every fifteen seconds; it was rung by clockwork. In 1874 the light was converted to run on mineral oil , which was stored in four 220-gallon tanks installed at
1620-579: A wooden dwelling was built alongside for the keeper. It was also known as the 'Beach Lighthouse'. In the mid-19th century both towers still had Argand lamps and reflectors (eleven of each in the High Light, three in the Low Light); they both displayed a fixed white light. In 1866 the Low Light was again moved and rebuilt (to a design by James Douglass ), this time as a wrought iron structure. It
1701-438: Is inserted through the boot and is bent to hold the reed against the shallot. The wire is moved up or down using a tuning knife in order to change the length of the tongue that is permitted to vibrate, thereby changing the pitch produced by the pipe. The resonator joins with the upper opening of the shallot and extends above the boot. The resonator may be made in a wide variety of lengths, shapes, and configurations, depending on
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#17327808587401782-425: Is not possible with normal organ pipes. Volume adjustment was available to the organist by means of a balanced expression pedal which varied the wind pressure delivered to the free reed stop. This type of free reed was popular among certain organ builders of the nineteenth century due to the increased interest in a more expressive aesthetic. The tonal characteristics of reed pipes are determined by several factors,
1863-419: Is one example. Race Rocks Light in western Canada is painted in horizontal black and white bands to stand out against the horizon. 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 trigonometry (see Distance to the horizon ) as D = 1.22 H {\displaystyle D=1.22{\sqrt {H}}} , where H
1944-505: 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. There are two types of lighthouses: ones that are located on land, and ones that are offshore. Reed pipe A reed pipe (also referred to as
2025-510: Is the height above water in feet, and D is the distance from the lighthouse to the horizon in nautical miles, the lighthouse range . 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
2106-622: The Florida Reef along the Florida Keys, beginning with the Carysfort Reef Light 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 ) similar to those used for offshore oil exploration . Aligning two fixed points on land provides
2187-405: The "Reed" class, and some stops from the "Hybrid" class. The reed stops of an organ are collectively called the "reed-work". A reed pipe comprises a metal tongue (the reed) which rests against a shallot , in which is carved a tunnel. The reed and shallot are held in place by a wooden wedge . This assembly protrudes from the underside of the block and hangs down into the boot . A tuning wire
2268-513: 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 in Britain and the St. George Reef Light of California. In shallower bays, Screw-pile lighthouse ironwork structures are screwed into
2349-466: 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 mantle of thorium dioxide suspended over the flame, creating a bright, steady light. The Argand lamp used whale oil , colza , olive oil or other vegetable oil as fuel, supplied by a gravity feed from
2430-619: The Trinity House Planning Centre in Harwich . The lighthouse, along with Southwold lighthouse to the south, was threatened with closure by Trinity House in 2005, with shipping companies increasingly using satellite navigation systems rather than relying on lighthouses. Both lighthouses were reprieved in 2009 following a review by Trinity House that found that satellite navigation systems were not yet sufficiently reliable. The main light at Lowestoft continues to use
2511-405: 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
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2592-495: 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
2673-405: The base of the tower. In 1881, the Low Light was again improved and showed an occulting light (being eclipsed for three seconds every thirty seconds). In 1883, due to the encroaching sea, the lighthouse was moved inland. In 1894 a reed fog horn had been installed; it sounded a seven-second blast every half minute during foggy weather. It was housed in a wooden building on ground level, beneath
2754-491: The beam was too narrow to be seen easily. 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 or pattern specific to a lighthouse. For example, the Scheveningen Lighthouse flashes are alternately 2.5 and 7.5 seconds. Some lights have sectors of
2835-406: 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
2916-533: The collapse of the Soviet government in 1990s, most of the official records on the locations, and condition, of these lighthouses were reportedly lost. Over time, the condition of RTGs in Russia degraded; many of them fell victim to vandalism and scrap metal thieves, who may not have been aware of the dangerous radioactive contents. Energy-efficient LED lights can be powered by solar panels , with batteries instead of
2997-488: 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
3078-572: The design by Sir Thomas Matthews ) they were fitted by Trinity House in all its oil-lit lighthouses. The Low Light was discontinued in August 1923, the Stanford Channel no longer being navigable. In 1938 the High Light was connected to mains electricity; electric filament lamps were installed and placed within a new fourth-order 'twin' optic made up of four dioptric panels (arranged as two side-by-side pairs, placed back to back). The optic
3159-422: The desired tone quality. An en chamade is a specific type of reed which is mounted horizontally on the organ case rather than stood vertically inside the organ case. This is done to project the tone more directly at the listener. In cases where this cannot be done, hooded reeds (generally trumpets) are used. This method of construction projects the sound in the same manner with a vertical resonator which turns at
3240-625: 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 , 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
3321-473: 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 developed the multi-part Fresnel lens for use in lighthouses. His design allowed for
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3402-475: The entrance into a harbor, such as New London Harbor Light . 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
3483-449: The first lights to be built by Trinity House. They marked the southern approach to Yarmouth Roads which, in the seventeenth century, was a key roadstead and anchorage , in frequent use both by vessels engaged in the local herring trade and by colliers on the route from Newcastle to London . The current lighthouse was built in 1874 and stands 16 metres (52 ft) tall, 37 metres (121 ft) above sea level. The light, which has
3564-477: The keepers). In 1866 the venerable lighthouse was described as a round tower, forty feet high and twenty feet in diameter, built of brick and stone, surmounted by a lantern seven feet high and six feet in diameter, glazed with plate glass. In 1870 the decision was taken to electrify the High Light, and because the tower itself was deemed not to be strong enough to support the new arc lamp and other equipment it had to be rebuilt. The new tower (the present lighthouse)
3645-455: 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 muntins (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 and grounding system connected to
3726-399: The latter case, whether or not the taper is inverted) greatly affects the pipe's timbre . Likewise, the "cut" (referring to the depth of the shallot and the shape of the opening) and the closed-end shape (whether the closed end of the shallot is flat, domed, or Schiffschen ) determine whether the tone is more Baroque or more Romantic. In addition, the type of block (whether a standard shape or
3807-535: The light is concentrated, if needed, by the "lens" or "optic". Power sources for lighthouses in the 20th–21st centuries vary. Originally lit by open fires and later candles, the Argand hollow wick lamp and parabolic reflector were introduced in the late 18th century. Whale oil was also used with wicks as the source of light. Kerosene became popular in the 1870s and electricity and acetylene gas derived on-site from calcium carbide began replacing kerosene around
3888-480: The light, along with a pair of two-horsepower Tangye gas engines to provide compressed air . The fog bell continued in use, but only to cover the interval between the appearance of fog and the fog horn commencing to sound. The Low Light was again moved to a new position (250 ft (76 m) further inland) in 1899, the sea having further encroached on the Ness. At the same time it was converted to run on coal gas,
3969-509: 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 the number of lighthouses being constructed increased significantly due to much higher 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
4050-469: 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 (pronounced / f r eɪ ˈ n ɛ l / ) 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
4131-470: The luminosity of traditional oil lights. 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 , 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
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#17327808587404212-421: 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
4293-409: The most important of which is the interaction between the shallot and the tongue. The thickness and curve of the tongue itself play an important role in determining the tonal quality of the pipe. When voicing a reed pipe, the voicer will take great care in shaping the curve of the tongue, because this controls how the tongue beats against the shallot. Whether the shallot is cylindrical or tapered (and, in
4374-496: 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
4455-402: The number of operational lighthouses has declined due to the expense of maintenance and the advent of much cheaper, more sophisticated, and more effective electronic navigational systems. Before the development of clearly defined ports , 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
4536-503: The resonator, however, is quite important: an inverted-conical resonator (such as is typical with a Trumpet rank) produces more harmonics than does a cylindrical resonator (like that of a Clarinet rank). There are generally two main types of reed stops: chorus reeds (such as the Trumpet, Clairon and Bombarde), whose main function is to blend with the flue stops and reinforce the full organ; and solo reeds or orchestral reeds (such as
4617-465: 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. 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
4698-451: 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
4779-458: The shallot (hence the German term for the reed — durchschlagend ). In the other form of the reed, an enclosed boot does not exist (as in normal reed pipes); therefore, all the tongues are held together in the same chamber, as in the harmonica , accordion , or harmonium . This arrangement makes it possible to change the volume produced without changing its pitch by varying the wind pressure, which
4860-413: The shallot. This produces the pipe's sound. The wind passes through the shallot and up into the resonator, which focuses and refines the sound wave produced by the reed. The length of the air column as well as the length, mass, and stiffness of the reed itself, determine the frequency of the instrument. A less-common type of reed construction is the free reed . The term refers to two types of reeds where
4941-554: The siege of Atlanta, designed and built some of the most exotic lighthouses in the most difficult locations on the U.S. Great Lakes . 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). In a lighthouse, the source of light is called the "lamp" (whether electric or fuelled by oil) and
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#17327808587405022-528: The surface during periods of fog or low clouds, as at Point Reyes Lighthouse . Another example is in San Diego , California : 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 . As technology advanced, prefabricated skeletal iron or steel structures tended to be used for lighthouses constructed in
5103-599: The third and most famous Eddystone Lighthouse , but some builders are well known for their work in building multiple lighthouses. The Stevenson family ( Robert , Alan , David , Thomas , David Alan , and Charles ) made lighthouse building a three-generation profession in Scotland. Richard Henry Brunton designed and built 26 Japanese lighthouses in Meiji Era Japan, which became known as Brunton's "children". Blind Irishman Alexander Mitchell invented and built
5184-421: The tongue does not beat directly against the shallot in order to produce the reed tone, which creates a unique sound (these are most commonly used on nineteenth-century German or French organs). In one case, the free reed stop will appear from the outside like a normal reed (complete with boot, tuning wire, and resonator, etc.). The only difference lies in the action of the tongue (see above), which beats "through"
5265-486: 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 € 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
5346-480: The turn of the 20th century. Carbide was promoted by the Dalén light , which automatically lit the lamp at nightfall and extinguished it at dawn. In the second half of the 20th century, many remote lighthouses in Russia (then Soviet Union ) were powered by radioisotope thermoelectric generators (RTGs). These had the advantage of providing power day or night and did not need refuelling or maintenance. However, after
5427-488: The twin 4th order 250mm catadioptric lenses with a range of 23 nautical miles (43 km; 26 mi). The current light characteristic is one white flash every 15 seconds (Fl(1).W.15s). The lighthouse, along with two cottages originally used by lighthouse keepers, is a Grade II listed building . Lighthouse Lighthouses mark dangerous coastlines, hazardous shoals , reefs , rocks, and safe entries to harbors; they also assist in aerial navigation . Once widely used,
5508-535: 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 . The black and white barber pole spiral pattern of Cape Hatteras Lighthouse
5589-643: 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 , Newfoundland, and Makapuu Point , Hawaii, used
5670-437: 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
5751-509: Was also displayed, from a window lower down in the tower, towards Corton Sands to the north-east. In 1901 the High Lighthouse was fitted with a Kitson oil vapour burner, which increased the intensity of the beam from 63,000 to 241,000 candlepower. This was the first installation of an incandescent petroleum vapour burner in an English lighthouse; the initial trial proved successful and subsequently (after modifications were made to
5832-459: 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 to 1759; 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 ",
5913-683: 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). Until 1782 the source of illumination had generally been wood pyres or burning coal. The Argand lamp , invented in 1782 by
5994-427: Was completed in 1874; however, due to the successful development of paraffin oil as an efficient and economical illuminant in the meantime, the new tower was equipped with a Douglass 4-wick paraffin burner instead. The new High Light was provided with a revolving first-order dioptric optic manufactured by Chance & co. , an 'octagonal drum of lenses' which flashed white every thirty seconds. A fixed red light
6075-445: Was lit with three candles which showed through a sash window in the upper storey. Rebuilt again in 1779, it was equipped with an open-cupped oil lamp which burned sperm oil . In 1777 the brazier in the High Light was replaced with an innovative form of reflector known as a 'spangle light': 126 lamp wicks (fed from an oil cistern by a common fuel line) were set in a circle around a central column on which were glued 4,000 tiny mirrors; it
6156-478: Was mounted on a mercury float pedestal and rotated by a weight-driven clockwork. Each side of the optic was fitted with an automatic lamp changer , which would substitute a battery voltage lamp for the mains voltage lamp in the event of a power failure; Planté batteries were installed and trickle-charged from the mains, to provide the emergency power. The light was automated in 1975 and further modernised in 1997, since when it has been monitored and controlled from
6237-465: Was moved up onto the cliffs above the Denes - the location of the present lighthouse - to assist vessels further out to sea; this new 'High Light' was lit using a coal fire brazier. The remaining 'Low Light' was discontinued in 1706 following sea encroachment, but then re-established in 1730 as a wooden tower that could be easily moved in response to further changes to the Stamford Channel and shoreline. It
6318-435: Was placed on the point of Lowestoft Ness, 515 yards (471 m) from the previous Low Light (the position of the Stamford Channel having altered). Accommodation for two keepers was provided in a 'neat white brick building' alongside. The new Low Light (also known as Lowestoftness Lighthouse ) was lit by a three-wick oil burner set within a second-order fixed catadioptric optic designed by James Timmins Chance , which gave
6399-416: Was said to be visible some 20 nautical miles (37 km; 23 mi) out to sea. In 1796 improvements were made to both towers and they were each provided with Argand lamps and parabolic reflectors . In 1832 the position of the Low Light was moved from the Denes to the beach. At the same time it was rebuilt as 'a lantern on a framing of timber upon a brick foundation'. The structure was painted white and
6480-506: Was the predominant light source in lighthouses from the 1900s to the 1960s, when electric lighting had become dominant. 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 1777, known as a catoptric system. This rudimentary system effectively collimated
6561-598: Was used in 1823 in the Cordouan lighthouse at the mouth of the Gironde estuary ; its light could be seen from more than 20 miles (32 km) out. Fresnel's invention increased the luminosity of the lighthouse lamp by a factor of four and his system is still in common use. The introduction of electrification and automatic lamp changers began to make lighthouse keepers obsolete. For many years, lighthouses still had keepers, partly because lighthouse keepers could serve as
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