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Solomons Lump Light
Solomons Lump Light is a lighthouse in the Chesapeake Bay, the abbreviated remains of a caisson light built in 1895. That structure replaced a screw-pile light built on the same spot in 1875, which in turn superseded the Fog Point Light. History The Fog Point Light, on the northwestern corner of Smith Island, marked the entrance to Kedges Strait from 1827. By 1872 it was held to be ineffective in protecting a shoal extending north from the island, and a new light was sought specifically to mark the shoal. In 1875 a five-legged screw-pile structure was built, which survived until 1893, when ice knocked it over. Initial plans to replace it with a new screw-pile light were changed when extra funds became available from the savings in constructing Wolf Trap Light in Virginia, so a caisson structure was erected instead in 1895, using the pneumatic process to sink it in place. The bottom being soft, the caisson sank further than expected, and an extra course of plates had to be ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caisson (engineering)
In geotechnical engineering, a caisson (; borrowed , , an augmentative of ) is a watertight retaining structure. It is used, for example, to work on the foundation (architecture), foundations of a bridge pier (architecture), pier, for the construction of a concrete dam, or for the repair of ships. Caissons are constructed in such a way that the water can be pumped out, keeping the work environment dry. When piers are being built using an open caisson, and it is not practical to reach suitable soil, Deep foundation, friction pilings may be driven to form a suitable sub-foundation. These piles are connected by a foundation pad upon which the column pier is erected. Caisson engineering has been used since at least the 19th century, with three prominent examples being the Royal Albert Bridge (completed in 1859), the Eads Bridge (completed in 1874), and the Brooklyn Bridge (completed in 1883). Types To install a caisson in place, it is brought down through soft mud until a suitable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresnel Lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens (optics), lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections. The simpler Dioptrics, dioptric (purely refraction, refractive) form of the lens was first proposed by Georges-Louis Leclerc, Comte de Buffon, and independently reinvented by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. The Catadioptric system, catadioptric (combining refraction and reflection) form of the lens, entirely invented by Fresnel, has outer Prism (optics), prismatic elements that use total internal reflection as well as refraction to capture more oblique light from the light source and add it to the beam, making it visible at greater distances. The design allows 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouse
A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lens (optics), lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, rocks, and safe entries to harbors; they also assist in aerial navigation. Once widely used, 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. History Ancient lighthouses 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 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 promontory, prom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chesapeake Bay
The Chesapeake Bay ( ) is the largest estuary in the United States. The bay is located in the Mid-Atlantic (United States), Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula, including parts of the Eastern Shore of Maryland, the Eastern Shore of Virginia, and the state of Delaware. The mouth of the bay at its southern point is located between Cape Henry and Cape Charles (headland), Cape Charles. With its northern portion in Maryland and the southern part in Virginia, the Chesapeake Bay is a very important feature for the ecology and economy of those two states, as well as others surrounding within its watershed. More than 150 major rivers and streams flow into the bay's drainage basin, which covers parts of six states (New York (state), New York, Pennsylvania, Delaware, Maryland, Virginia, and West Virginia) and all of Washington, D.C. The bay is approximately long from its northern headwaters in the Susquehanna River to its outlet i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Construction began in 1838 at the mouth of the Thames and was known as the Maplin Sands lighthouse, and first lit in 1841. However, though its construction began later, the Wyre Light in Fleetwood, Lancashire, was the first to be lit (in 1840). In the United States, several screw-pile lighthouses were constructed in the Chesapeake Bay due to its estuarial soft bottom. North Carolina's sounds and river entrances also once had many screw-pile lights. The characteristic design is a -storey hexagonal wooden building with dormers and a cupola light room. History Non-screwpile (straightpile) tubular skeletal tower lighthouses were built, usually of cast-iron but also of wrought-iron piles, both onshore and offshore, typically on soft bottoms such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fog Point Light
The Fog Point Light was a historic lighthouse located at Fog Point, the northwestern tip of Smith Island, Maryland in the Chesapeake Bay. History This light was constructed in 1827 by John Donahoo to mark the entrance to the Kedges Strait north of Smith Island. Originally equipped with 10 Argand lamps and reflectors, it received a fifth-order Fresnel lens in 1855. This light's isolated location on swampy ground was cause for concern, and in 1872 a Lighthouse Board report noted it as having little value. In 1875 it was supplanted by the Solomons Lump Light, which stood in the strait to the northeast. The old light was abandoned, and no trace of it remains. References *Fog Point Light from the Chesapeake Chapter of the United States Lighthouse Society The United States Lighthouse Society (USLHS) 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 affili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smith Island, Maryland
Smith Island is a collection of three distinct island communities – Tylerton, Rhodes Point, and Ewell, Maryland – on the Chesapeake Bay, on the border of Maryland and Virginia territorial waters in the United States. The island is the last inhabited island in Maryland that is not accessible by car (the Virginia portion of the island is not currently inhabited). Most of the islands are eroding due to tidal currents and sea level rise; a study conducted in 2008 by the DNR reported that Smith Island is expected to completely erode by 2100 if no action is taken. The island's population is approximately 220, down from a peak of about 800. On its Maryland side, Smith Island is a census-designated place (CDP) in Somerset County. It is included in the Salisbury, Maryland-Delaware Metropolitan Statistical Area. Geography Smith Island lies approximately west of Crisfield, Maryland, across the Tangier Sound portion of the Chesapeake Bay. The island consists of three communities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Construction began in 1838 at the mouth of the Thames and was known as the Maplin Sands lighthouse, and first lit in 1841. However, though its construction began later, the Wyre Light in Fleetwood, Lancashire, was the first to be lit (in 1840). In the United States, several screw-pile lighthouses were constructed in the Chesapeake Bay due to its estuarial soft bottom. North Carolina's sounds and river entrances also once had many screw-pile lights. The characteristic design is a -storey hexagonal wooden building with dormers and a cupola light room. History Non-screwpile (straightpile) tubular skeletal tower lighthouses were built, usually of cast-iron but also of wrought-iron piles, both onshore and offshore, typically on soft bottoms such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolf Trap Light
Wolf Trap Light is a caisson lighthouse in the Virginia portion of the Chesapeake Bay, about seven and a half miles northeast of New Point Comfort Light. It is listed on the National Register of Historic Places. History Wolf Trap Shoal juts into the bay from Winter Harbor, a point a few miles north of Mobjack Bay and the York River. It got its name from the 1691 grounding of HMS ''Wolf'', a British naval vessel engaged in enforcing the Navigation Act and in combating piracy. In 1821 a lightship was stationed at this spot, and after refurbishment in 1854, the original ship was destroyed by Confederate raiders in 1861 during the Civil War. Two years later a replacement ship was put on station. In 1870 a screwpile lighthouse was constructed on a hexagonal foundation, the house being prefabricated at the station at Lazzaretto Point in Baltimore. This light survived until 22 January 1893, when ice tore the house from its foundation. The keeper was able to escape, but the house was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresnel Lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens (optics), lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections. The simpler Dioptrics, dioptric (purely refraction, refractive) form of the lens was first proposed by Georges-Louis Leclerc, Comte de Buffon, and independently reinvented by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. The Catadioptric system, catadioptric (combining refraction and reflection) form of the lens, entirely invented by Fresnel, has outer Prism (optics), prismatic elements that use total internal reflection as well as refraction to capture more oblique light from the light source and add it to the beam, making it visible at greater distances. The design allows 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cherrystone Bar Light
The Cherrystone Bar Light was a lighthouse located at the entrance to Cape Charles, Virginia harbor in the Chesapeake Bay. It was the only light in the bay moved to another location, becoming the Choptank River Light in 1921. History This light was constructed shortly before the Civil War, and like the other Virginia lights, it was put out of commission by the Confederate forces. It was reactivated by Union forces in 1862. In 1919, a simple skeleton tower on a small caisson was erected to replace the old light. The following year, the house was lifted from its foundation and barged north, where it was set on a new foundation to replace the Choptank River Light, which had been destroyed by ice in 1918. This light was eventually dismantled in 1964, but the caisson light at the original location remains in use. References *Cherrystone Bar Light from the Chesapeake Chapter of the United States Lighthouse Society The United States Lighthouse Society (USLHS) is a non-profit organiza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouses Completed In 1895
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. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, rocks, and safe entries to harbors; they also assist in aerial navigation. Once widely used, 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. History Ancient lighthouses 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 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 moder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
