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Cobb Point Bar Light
The Cobb Point Bar Light (also called Cobb Island Bar Light) was a screw-pile lighthouse located in the Potomac River. History A light at Cobb Point was first requested in 1875 to mark the entrance to the tricky channel leading into the Wicomico River (not to be confused with the river of the same name on the Eastern Shore). After two additional requests, funds were finally appropriated in 1887. Construction was delayed, however, and the light was not commissioned until Christmas 1889. A fire in 1939 caused by light keeper Matthew Wicke, resulted in heavy damage, and in the following year the house was torn down, replaced by a beacon set on the same foundation. In the late 1800s, they built some new lighthouses on the Potomac River. This was because more ships were using the river, and the ships were getting bigger and needed deeper water. Around that time, there were steamships, like big boats, that operated on the Chesapeake Bay and its smaller rivers. They carried people and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potomac River
The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved August 15, 2011 with a drainage area of 14,700 square miles (38,000 km2), and is the fourth-largest river along the East Coast of the United States and the 21st-largest in the United States. Over 5 million people live within its watershed. The river forms part of the borders between Maryland and Washington, D.C. on the left descending bank and between West Virginia and Virginia on the right descending bank. Except for a small portion of its headwaters in West Virginia, the North Branch Potomac River is considered part of Maryland to the low-water mark on the opposite bank. The South Branch Potomac River lies completely within the state of West Virginia except for its headwaters, which lie in Virginia. Course The Potomac River runs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wicomico River (Potomac River)
The Wicomico River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 15, 2011 tributary of the lower tidal portion of the Potomac River located in the U.S. state of Maryland south of Washington, DC. The river empties into the Potomac at Cobb Island Cobb Island is a small island located at the confluence of the Potomac and Wicomico rivers in southern Charles County, Maryland, United States. It is located approximately south of Washington, and is considered to be within the Washington, D.C ... and St. Margaret's Island. Its watershed area (excluding water) is , with 2% impervious surface in 1994Wicomico (on Potomac), MD Surf your watershed, Watershed profile accessed June 13, 2012 in Charles County, Maryland, Charles, St. Mary's, and southern Prince George's counties. The lower section of the river forms part of the boundary between Charles and St. Mary's counties. The Wicomico River was designated as a S ... [...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 as m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cast-iron
Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impurities which allow cracks to pass straight through, grey cast iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material breaks, and ductile cast iron has spherical graphite "nodules" which stop the crack from further progressing. Carbon (C), ranging from 1.8 to 4 wt%, and silicon (Si), 1–3 wt%, are the main alloying elements of cast iron. Iron alloys with lower carbon content are known as steel. Cast iron tends to be brittle, except for malleable cast irons. With its relatively low melting point, good fluidity, castability, excellent machinability, resistance to deformation and wear resistance, cast irons have become an engineering material with a wide range of applications and are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or woodchips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. More recently it emerged as a feedstock for the productio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 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. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The ''catadioptric'' form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source and add it to the beam of a lighthouse, making the light visible from greater distances. Description The Fresnel lens redu ... [...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 as m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wicomico River (Potomac River Tributary)
The Wicomico River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed August 15, 2011 tributary of the lower tidal portion of the Potomac River located in the U.S. state of Maryland south of Washington, DC. The river empties into the Potomac at Cobb Island Cobb Island is a small island located at the confluence of the Potomac and Wicomico rivers in southern Charles County, Maryland, United States. It is located approximately south of Washington, and is considered to be within the Washington, D.C ... and St. Margaret's Island. Its watershed area (excluding water) is , with 2% impervious surface in 1994Wicomico (on Potomac), MD Surf your watershed, Watershed profile accessed June 13, 2012 in Charles County, Maryland, Charles, St. Mary's, and southern Prince George's counties. The lower section of the river forms part of the boundary between Charles and St. Mary's counties. The Wicomico River was designated as a S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 largest and oldest lighthouse organizations in the world. History Founded in 1984 by Wayne Wheeler and initially headquartered in San Francisco, California, one of the United States Lighthouse Society's first major projects was the purchase of the lightship LV605 in 1986 from a private individual. The organization subsequently invested $400,000 and more than 40,000 volunteer hours in the preservation and restoration of the vessel. In 2003 the society received the California Governor's Historic Preservation Award for its work on the ship. The society relocated from California to Hansville, Washington in 2008, siting its headquarters at the historic Point No Point Lighthouse, which it rented from Kitsap County (the county, in turn, lease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouses Completed In 1889
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 has become uneconomical since the advent of much cheaper, more sophisticated and 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 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 reefs a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouses In Maryland
This is a list of all lighthouses in the U.S. state of Maryland as identified by the United States Coast Guard. There are fourteen active lights in the state as well as three automated caissons and eleven skeleton towers replacing previously staffed lights. The first lighthouse in the state was lit in 1822 and the last in 1965 (ignoring automated towers erected later); the oldest surviving structure is the Pooles Island Light and the oldest still active is the Cove Point Light. The tallest extant tower is the Craighill Channel Lower Range Rear Light. If not otherwise noted, focal height and coordinates are taken from the United States Coast Guard ''Light List'', while location and dates of activation, automation, and deactivation are taken from the United States Coast Guard Historical information site for lighthouses. Locations of demolished lights have been estimated using National Oceanic and Atmospheric Administration (NOAA) navigational charts. References {{Lighthous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouses In The Chesapeake Bay
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 has become uneconomical since the advent of much cheaper, more sophisticated and 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 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 reefs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
