Clematis is a genus of about 300 species within the buttercup family, Ranunculaceae. Their garden hybrids have been popular among gardeners, beginning with Clematis × jackmanii, a garden standby since 1862, they are of Chinese and Japanese origin. Most species are known as clematis in English, while some are known as traveller's joy, a name invented for the sole British native, C. vitalba, by the herbalist John Gerard. The genus name is from Ancient Greek clématis. Over 250 species and cultivars are known named for their originators or particular characteristics; the genus is composed of vigorous, climbing vines / lianas. The woody stems are quite fragile until several years old. Leaves are opposite and divided into leaflets and leafstalks that twist and curl around supporting structures to anchor the plant as it climbs; some species are shrubby. The cool temperate species are deciduous, they grow best in cool, well-drained soil in full sun. Clematis species are found throughout the temperate regions of the Northern Hemisphere in the tropics.
Clematis leaves are food for the caterpillars of some Lepidoptera species, including the willow beauty. The timing and location of flowers varies; the genus Clematis was first published by Carl Linnaeus in Species Plantarum in 1753, the first species listed being Clematis viticella. The genus name long pre-dates Linnaeus, it was used in Classical Greek for various climbing plants, is based on κλήμα, meaning vine or tendril. Some morphologically distinctive taxa lacking the combination of characters defining Clematis were segregated as the genera Archiclematis and Naravelia. DNA sequence studies have found that these two genera are nested in Clematis, the morphological characters they were erected on being either reversals or misinterpretations, that the genera should be reduced to the synonymy of Clematis. Naravelia is a monophyletic group within Clematis. Species to be transferred include. Archiclematis alternata Clematis antonii, syn. Naravelia antonii Clematis dasyoneura, syn. Naravelia dasyoneura Clematis horripilata, syn.
Naravelia laurifolia Clematis zeylanica, syn. Naravelia zeylanica A partial list of species: Clematis addisonii Britt. – Addison's leather flower Clematis albicoma Wherry – whitehair leather flower Clematis alpina Mill. – alpine clematis Clematis aristata R. Br. Ex Ker Gawl. – Australian clematis Clematis armandii – Armand clematis Clematis baldwinii Torr. & A. Gray – pine hyacinth Clematis bigelovii Torr. – Bigelow clematis Clematis brachiata Thunb. – traveller's joy Clematis campaniflora Brot. – Portuguese clematis Clematis catesbyana – satin curls Clematis chinensis Osbeck – wei ling xian in Chinese Clematis chrysocoma Franch. – gold wool clematis Clematis cirrhosa L. – includes the'Freckles','Wisley Cream', and'Jingle Bells' cultivars Clematis cirrhosa v. balearica Clematis coactilis Keener – Virginia whitehair leather flower Clematis columbiana Torr. & A. Gray – British Columbia virgin's bower Clematis crispa L. – swamp leather flower Clematis cunninghamii Clematis dioica L. – cabellos de angel Clematis drummondii Torr.
& A. Gray – Drummond clematis Clematis durandii Clematis fawcettii F. Muell. Clematis flammula L. – fragrant virgin's bower Clematis florida Thunb. – Asian clematis Clematis fremontii S. Watson – Fremont's leather flower Clematis glaucophylla Small – whiteleaf leather flower Clematis glycinoides DC. – headache vine Clematis gouriana – Indian traveller's joy Clematis henryi Oliv. Clematis hirsutissima Pursh – hairy clematis Clematis hedysarifolia DC. Clematis integrifolia L. Clematis ispahanica Bioss Clematis × jackmanii T. Moore – Jackman's clematis Clematis koreana Kom. – Korean clematis Clematis lanuginosa Lindl. & Paxton Clematis lasiantha Nutt. – pipestem clematis Clematis leptophylla H. Eichler Clematis ligusticifolia Nutt. – western white clematis, hierba de chivo Clematis macropetala Ledeb. – downy clematis Clematis mandshurica Clematis marmoraria Sneddon – New Zealand dwarf clematis Clematis microphylla DC. – small-leaved clematis Clematis montana Buch.-Ham. Ex DC. – anemone clematis Clematis morefieldii Kral – Huntsville vasevine Clematis napaulensis DC.
Clematis occidentalis DC. – western blue virginsbower Clematis ochroleuca Ait. – curlyheads Clematis orientalis L. – Chinese clematis Clematis palmeri Rose – Palmer clematis Clematis paniculata J. F. Gmel. – puawhananga Clematis patens C. Morren & Decne. Clematis pauciflora Nutt. – ropevine clematis Clematis pickeringii A. Gray Clematis pitcheri Torr. & A. Gray – bluebill Clematis pubescens Hügel ex Endl. – common clematis Clematis recta L. – ground clematis Clematis reticulata Walter – netleaf leather flower Clematis rhodocarpa Rose Clematis smilacifolia Wall. Clematis socialis Kral – Alabama leather flower Clematis stans Siebold & Zucc. – kusabotan Clematis tangutica Korsh. – golden clematis Clematis terniflora DC. – sweet autumn clematis Clematis texensis Buckley – scarlet leather flower Clematis versicolor – manycolored leather flower Clematis verticillaris – purple
Sissinghurst Castle Garden
Sissinghurst Castle Garden, at Sissinghurst in the Weald of Kent in England, was created by Vita Sackville-West and writer, her husband Harold Nicolson and diplomat. It is among the most famous gardens in England and is designated Grade I on Historic England's register of historic parks and gardens, it was bought by Sackville-West in 1930, over the next thirty years, working with, succeeded by, a series of notable head gardeners and Nicolson transformed a farmstead of "squalor and slovenly disorder" into one of the world's most influential gardens. Following Sackville-West's death in 1962, the estate was gifted to the National Trust for Places of Historic Interest or Natural Beauty, it is one of the Trust's most popular properties, with nearly 200,000 visitors in 2017. The gardens contain an internationally respected plant collection the assemblage of old garden roses; the writer Anne Scott-James considered the roses at Sissinghurst to be "one of the finest collections in the world". A number of plants propagated in the gardens bear names related to people connected with Sissinghurst or the name of the garden itself.
The garden design is based on axial walks that open onto enclosed gardens, termed "garden rooms", one of the earliest examples of this gardening style. Among the individual "garden rooms", the White Garden has been influential, with the horticulturalist Tony Lord describing it as "the most ambitious... of its time, the most entrancing of its type."The site of Sissinghurst is ancient and has been occupied since at least the Middle Ages. The present-day buildings began. In 1554 Sir John's daughter Cecily married Thomas Sackville, 1st Earl of Dorset, an ancestor of Vita Sackville-West. By the 18th century the Baker's fortunes had waned, the house, renamed Sissinghurst Castle, was leased to the government to act as a prisoner-of-war camp during the Seven Years' War; the prisoners caused great damage and by the 19th century much of Sir Richard's house had been demolished. In the mid-19th century, the remaining buildings were in use as a workhouse, by the 20th century Sissinghurst had declined to the status of a farmstead.
In 1928 the castle remained unsold for two years. Sackville-West was born in 1892 at the ancestral home of the Sackvilles, but for her sex, Sackville-West would have inherited Knole on the death of her father in 1928. Instead, following primogeniture, the house and the title passed to her uncle, a loss she felt deeply. In 1930, after she and Nicolson became concerned that their home Long Barn was threatened by development, Sackville-West bought Sissinghurst Castle. On purchasing Sissinghurst, Sackville-West and Nicolson inherited little more than some oak and nut trees, a quince, a single old rose. Sackville-West planted the noisette rose'Madame Alfred Carrière' on the south face of the South Cottage before the deeds to the property had been signed. Nicolson was responsible for planning the garden design, while Sackville-West undertook the planting. Over the next thirty years, working with her head gardeners, she cultivated some two hundred varieties of roses and large numbers of other flowers and shrubs.
Decades after Sackville-West and Nicolson created "a garden where none was", Sissinghurst remains a major influence on horticultural thought and practice. The site is ancient. Nigel Nicolson, in his 1964 guide, Sissinghurst Castle: An Illustrated History, records the earliest owners as the de Saxinhersts. Stephen de Saxinherst is named in an 1180 charter about the nearby Combwell Priory. At the end of the 13th century the estate had passed, to the de Berhams. Nicolson suggested that the de Berhams constructed a moated house in stone, of an appearance similar to that of Ightham Mote, replaced by a brick manor. More recent studies, including those of Nicolson's son, cast doubt on the existence of an earlier stone manor, suggesting instead that the brick house, or a timber construction of a earlier date, occupying the corner of the orchard nearest the moat, was the earliest house on the site. Edward I is reputed to have stayed at this house in 1305. In 1490 the de Berhams sold the manor of Sissinghurst to Thomas Baker of Cranbrook.
The Bakers were cloth producers and in the following century, through marriage and careers at court and in the law, Thomas's successors expanded their wealth and their estates in Kent and Sussex. In the 1530s Sir John Baker, one of Henry VIII's Privy Councillors, built a new brick gatehouse, the current West Range. In 1554 Sir John's daughter Cecily married Thomas Sackville, 1st Earl of Dorset, creating the earliest connection between the Sackville family and the house. Sir John's son Richard undertook a massive prodigy expansion in the 1560s; the Tower is part of that expansion, formed the entrance to a large courtyard house, of which the South Cottage and some walls are the only other remaining fragments. Sir Richard surrounded the mansion with an enclosed 700-acre deer park and in August 1573 entertained Queen Elizabeth I at Sissinghurst. After the collapse of the Baker family fortunes following the civil war, the building declined in importance. Horace Walpole visited in 1752: "yesterday, after twenty mishaps, we got to Sissinghurst for dinner.
There is a park in ruins and a house in ten times greater ruins." During the Seven Years' War, it became a prisoner-of-war camp. The historian Edward Gibbon serving in the Hampshire militia, was stationed there and recorded "the inconceivable dirtiness of the season, the country and the spot", it was during its use as a camp for French prisoners that the name Sissinghurst Ca
Columbus is a consolidated city-county located on the west central border of the U. S. state of Georgia. Located on the Chattahoochee River directly across from Phenix City, Columbus is the county seat of Muscogee County, with which it merged in 1970. Columbus is the third-largest city in the fourth-largest metropolitan area. According to the 2017 estimates from the U. S. Census Bureau, Columbus has a population of 194,058 residents, with 303,811 in the Columbus metropolitan area; the metro area joins the nearby Alabama cities of Auburn and Opelika to form the Columbus–Auburn–Opelika Combined Statistical Area, which has a 2017 estimated population of 499,128. Columbus lies 100 miles southwest of Atlanta. Fort Benning, the United States Army's Maneuver Center of Excellence and a major employer, is located south of the city in Chattahoochee County. Columbus is home to museums and tourism sites, including the National Infantry Museum, dedicated to the United States Army's Infantry Branch, it has the longest urban whitewater rafting course in the world constructed on the Chattahoochee River.
This was for centuries and more the traditional territory of the Creek Indians, who became known as one of the Five Civilized Tribes of the Southeast after European contact. Those who lived closest to white-occupied areas conducted considerable trading and adopted some European-American ways. Founded in 1828 by an act of the Georgia Legislature, Columbus was situated at the beginning of the navigable portion of the Chattahoochee River and on the last stretch of the Federal Road before entering Alabama; the city was named for Christopher Columbus, its founders influenced by the writings of Washington Irving. The plan for the city was drawn up by Dr. Edwin L. DeGraffenried, who placed the town on a bluff overlooking the river. Across the river to the west, where Phenix City, Alabama is now located, Creek Indians still lived until they were forcibly removed in 1836 by the federal government to make way for European-American settlers; the river served as Columbus's connection to the world enabling it to ship its commodity cotton crops from the plantations to the international cotton market via New Orleans and Liverpool, England.
The city's commercial importance increased in the 1850s with the arrival of the railroad. In addition, textile mills were developed along the river, bringing industry to an area reliant upon agriculture. By 1860, the city was one of the more important industrial centers of the South, earning it the nickname "the Lowell of the South," referring to an important textile mill town in Massachusetts; when the Civil War broke out in 1861, the industries of Columbus expanded their production. During the war, Columbus ranked second to Richmond in the manufacture of supplies for the Confederate army; the Eagle Manufacturing Company made textiles of various sorts but woolens for Confederate uniforms. The Columbus Iron Works manufactured cannons and machinery and Gray made firearms, Louis and Elias Haimon produced swords and bayonets. Smaller firms provided additional sundries; as the war turned negative, each faced exponentially growing struggled shortages of raw materials and skilled labor, as well as worsenting financial opportunities.
In addition to textiles, the city had an ironworks, a sword factory, a shipyard for the Confederate Navy. Unaware of Lee's surrender to Grant and the assassination of Abraham Lincoln and Confederates clashed in the Battle of Columbus, Georgia, on Easter Sunday, April 16, 1865, when a Union detachment of two cavalry divisions under Maj. Gen. James H. Wilson attacked the lightly-defended city and burned many of the industrial buildings. John Stith Pemberton, who developed Coca-Cola in Columbus, was wounded in this battle. Col. Charles Augustus Lafayette Lamar, owner of the last slave ship in America, was killed here. A historic marker has been erected in Columbus, it notes that this was the site of the "Last Land Battle in the War from 1861 to 1865." Reconstruction began immediately and prosperity followed. Factories such as the Eagle and Phenix Mills were revived and the industrialization of the town led to rapid growth; the Springer Opera House was built on 10th Street, attracting such notables as Irish writer Oscar Wilde.
The Springer is now the official State Theater of Georgia. By the time of the Spanish–American War, the city's modernization included the addition of trolleys extending to outlying neighborhoods such as Rose Hill and Lakebottom, a new water works. Mayor Lucius Chappell brought a training camp for soldiers to the area; this training camp named Camp Benning would grow into present-day Fort Benning, named for General Henry L. Benning, a native of the city. In the spring of 1866 the Ladies Memorial Association of Columbus passed a resolution to set aside one day annually to memorialize the Confederate dead; the secretary of the association, Mrs. Charles J. Williams, was directed to write a letter inviting the ladies of every Southern state to join them in the observance; the letter was written in March 1866 and sent to representatives of all of the principal cities in the South, including Atlanta, Montgomery, Richmond, St. Louis, Alexandria and New Orleans; this was the beginning of the influential work by ladies' organizations to honor the war dead.
The date for the holiday was selected by Elizabeth "Lizzie" Rutherford Ellis. She chose April 26, the first anniversary of Confederate General Johnston's final surrender to Union General Sherman at Bennett Place, North Carolina. For many in the South, that act marked the official end of the Civil War. In
Georgia (U.S. state)
Georgia is a state in the Southeastern United States. It began as a British colony in 1733, the last and southernmost of the original Thirteen Colonies to be established. Named after King George II of Great Britain, the Province of Georgia covered the area from South Carolina south to Spanish Florida and west to French Louisiana at the Mississippi River. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788. In 1802–1804, western Georgia was split to the Mississippi Territory, which split to form Alabama with part of former West Florida in 1819. Georgia declared its secession from the Union on January 19, 1861, was one of the original seven Confederate states, it was the last state to be restored to the Union, on July 15, 1870. Georgia is the 8th most populous of the 50 United States. From 2007 to 2008, 14 of Georgia's counties ranked among the nation's 100 fastest-growing, second only to Texas. Georgia is known as the Empire State of the South. Atlanta, the state's capital and most populous city, has been named a global city.
Atlanta's metropolitan area contains about 55% of the population of the entire state. Georgia is bordered to the north by Tennessee and North Carolina, to the northeast by South Carolina, to the southeast by the Atlantic Ocean, to the south by Florida, to the west by Alabama; the state's northernmost part is in the Blue Ridge Mountains, part of the Appalachian Mountains system. The Piedmont extends through the central part of the state from the foothills of the Blue Ridge to the Fall Line, where the rivers cascade down in elevation to the coastal plain of the state's southern part. Georgia's highest point is Brasstown Bald at 4,784 feet above sea level. Of the states east of the Mississippi River, Georgia is the largest in land area. Before settlement by Europeans, Georgia was inhabited by the mound building cultures; the British colony of Georgia was founded by James Oglethorpe on February 12, 1733. The colony was administered by the Trustees for the Establishment of the Colony of Georgia in America under a charter issued by King George II.
The Trustees implemented an elaborate plan for the colony's settlement, known as the Oglethorpe Plan, which envisioned an agrarian society of yeoman farmers and prohibited slavery. The colony was invaded by the Spanish during the War of Jenkins' Ear. In 1752, after the government failed to renew subsidies that had helped support the colony, the Trustees turned over control to the crown. Georgia became a crown colony, with a governor appointed by the king; the Province of Georgia was one of the Thirteen Colonies that revolted against British rule in the American Revolution by signing the 1776 Declaration of Independence. The State of Georgia's first constitution was ratified in February 1777. Georgia was the 10th state to ratify the Articles of Confederation on July 24, 1778, was the 4th state to ratify the United States Constitution on January 2, 1788. In 1829, gold was discovered in the North Georgia mountains leading to the Georgia Gold Rush and establishment of a federal mint in Dahlonega, which continued in operation until 1861.
The resulting influx of white settlers put pressure on the government to take land from the Cherokee Nation. In 1830, President Andrew Jackson signed the Indian Removal Act, sending many eastern Native American nations to reservations in present-day Oklahoma, including all of Georgia's tribes. Despite the Supreme Court's ruling in Worcester v. Georgia that U. S. states were not permitted to redraw Indian boundaries, President Jackson and the state of Georgia ignored the ruling. In 1838, his successor, Martin Van Buren, dispatched federal troops to gather the tribes and deport them west of the Mississippi; this forced relocation, known as the Trail of Tears, led to the death of over 4,000 Cherokees. In early 1861, Georgia became a major theater of the Civil War. Major battles took place at Chickamauga, Kennesaw Mountain, Atlanta. In December 1864, a large swath of the state from Atlanta to Savannah was destroyed during General William Tecumseh Sherman's March to the Sea. 18,253 Georgian soldiers died in service one of every five who served.
In 1870, following the Reconstruction Era, Georgia became the last Confederate state to be restored to the Union. With white Democrats having regained power in the state legislature, they passed a poll tax in 1877, which disenfranchised many poor blacks and whites, preventing them from registering. In 1908, the state established a white primary, they constituted 46.7% of the state's population in 1900, but the proportion of Georgia's population, African American dropped thereafter to 28% due to tens of thousands leaving the state during the Great Migration. According to the Equal Justice Institute's 2015 report on lynching in the United States, Georgia had 531 deaths, the second-highest total of these extralegal executions of any state in the South; the overwhelming number of victims were male. Political disfranchisement persisted through the mid-1960s, until after Congress passed the Voting Rights Act of 1965. An Atlanta-born Baptist minister, part of the educated middle class that had developed in Atlanta's African-American community, Martin Luther King, Jr. emerged as a national leader in the civil rights movement.
King joining with others to form the Southern Christian Leadership Conference in Atlanta in 1957 to provide political leadership for the Civil Rights Movement across the South. By the 1960s, the proportion of
Minnesota is a state in the Upper Midwest and northern regions of the United States. Minnesota was admitted as the 32nd U. S. state on May 11, 1858, created from the eastern half of the Minnesota Territory. The state has a large number of lakes, is known by the slogan the "Land of 10,000 Lakes", its official motto is L'Étoile du Nord. Minnesota is the 12th largest in area and the 22nd most populous of the U. S. states. This area is the center of transportation, industry and government, while being home to an internationally known arts community; the remainder of the state consists of western prairies now given over to intensive agriculture. Minnesota was inhabited by various indigenous peoples for thousands of years prior to the arrival of Europeans. French explorers and fur traders began exploring the region in the 17th century, encountering the Dakota and Ojibwe/Anishinaabe tribes. Much of what is today Minnesota was part of the vast French holding of Louisiana, purchased by the United States in 1803.
Following several territorial reorganizations, Minnesota in its current form was admitted as the country's 32nd state on May 11, 1858. Like many Midwestern states, it remained centered on lumber and agriculture. During the 19th and early 20th centuries, a large number of European immigrants from Scandinavia and Germany, began to settle the state, which remains a center of Scandinavian American and German American culture. In recent decades, immigration from Asia, the Horn of Africa, the Middle East, Latin America has broadened its demographic and cultural composition; the state's economy has diversified, shifting from traditional activities such as agriculture and resource extraction to services and finance. Minnesota's standard of living index is among the highest in the United States, the state is among the best-educated and wealthiest in the nation; the word Minnesota comes from the Dakota name for the Minnesota River: The river got its name from one of two words in the Dakota language,'Mní sóta' which means "clear blue water", or'Mnißota', which means cloudy water.
Native Americans demonstrated the name to early settlers by dropping milk into water and calling it mnisota. Many places in the state have similar names, such as Minnehaha Falls, Minneota, Minnetonka and Minneapolis, a combination of mni and polis, the Greek word for "city". Minnesota is the second northernmost U. S. state and northernmost contiguous state. Its isolated Northwest Angle in Lake of the Woods county is the only part of the 48 contiguous states lying north of the 49th parallel; the state is part of the U. S. region known as part of North America's Great Lakes Region. It shares a Lake Superior water border with Michigan and a land and water border with Wisconsin to the east. Iowa is to the south, North Dakota and South Dakota are to the west, the Canadian provinces of Ontario and Manitoba are to the north. With 86,943 square miles, or 2.25% of the United States, Minnesota is the 12th-largest state. Minnesota has gneisses that are about 3.6 billion years old. About 2.7 billion years ago, basaltic lava poured out of cracks in the floor of the primordial ocean.
The roots of these volcanic mountains and the action of Precambrian seas formed the Iron Range of northern Minnesota. Following a period of volcanism 1.1 billion years ago, Minnesota's geological activity has been more subdued, with no volcanism or mountain formation, but with repeated incursions of the sea, which left behind multiple strata of sedimentary rock. In more recent times, massive ice sheets at least one kilometer thick ravaged the state's landscape and sculpted its terrain; the Wisconsin glaciation left 12,000 years ago. These glaciers covered all of Minnesota except the far southeast, an area characterized by steep hills and streams that cut into the bedrock; this area is known as the Driftless Zone for its absence of glacial drift. Much of the remainder of the state outside the northeast has 50 feet or more of glacial till left behind as the last glaciers retreated. Gigantic Lake Agassiz formed in the northwest 13,000 years ago, its bed created the fertile Red River valley, its outflow, glacial River Warren, carved the valley of the Minnesota River and the Upper Mississippi downstream from Fort Snelling.
Minnesota is geologically quiet today. The state's high point is Eagle Mountain at 2,301 feet, only 13 miles away from the low of 601 feet at the shore of Lake Superior. Notwithstanding dramatic local differences in elevation, much of the state is a rolling peneplain. Two major drainage divides meet in Minnesota's northeast in rural Hibbing, forming a triple watershed. Precipitation can follow the Mississippi River south to the Gulf of Mexico, the Saint Lawrence Seaway east to the Atlantic Ocean, or the Hudson Bay watershed to the Arctic Ocean; the state's nickname, "Land of 10,000 Lakes", is apt, as there are 11,842 Minnesota lakes over 10 acres in size. Minnesota's portion of Lake Superior is the largest at 962,700 acres and deepest body of wate
Cast iron is a group of iron-carbon alloys with a carbon content greater than 2%. Its usefulness derives from its low melting temperature; the alloy constituents affect its colour 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, ductile cast iron has spherical graphite "nodules" which stop the crack from further progressing. Carbon ranging from 1.8 to 4 wt%, silicon 1–3 wt% are the main alloying elements of cast iron. Iron alloys with lower carbon content are known as steel. While this technically makes the Fe–C–Si system ternary, the principle of cast iron solidification can be understood from the simpler binary iron–carbon phase diagram. Since the compositions of most cast irons are around the eutectic point of the iron–carbon system, the melting temperatures range from 1,150 to 1,200 °C, about 300 °C lower than the melting point of pure iron of 1,535 °C.
Cast iron tends to be brittle, except for malleable cast irons. With its low melting point, good fluidity, excellent machinability, resistance to deformation and wear resistance, cast irons have become an engineering material with a wide range of applications and are used in pipes and automotive industry parts, such as cylinder heads, cylinder blocks and gearbox cases, it is resistant to weakening by oxidation. The earliest cast-iron artifacts date to the 5th century BC, were discovered by archaeologists in what is now Jiangsu in China. Cast iron was used in ancient China for warfare and architecture. During the 15th century, cast iron became utilized for cannon in Burgundy, in England during the Reformation; the amounts of cast iron used for cannon required large scale production. The first cast-iron bridge was built during the 1770s by Abraham Darby III, is known as The Iron Bridge. Cast iron was used in the construction of buildings. Cast iron is made from pig iron, the product of smelting iron ore in a blast furnace.
Cast iron can be made directly from the molten pig iron or by re-melting pig iron along with substantial quantities of iron, limestone and taking various steps to remove undesirable contaminants. Phosphorus and sulfur may be burnt out of the molten iron, but this burns out the carbon, which must be replaced. Depending on the application and silicon content are adjusted to the desired levels, which may be anywhere from 2–3.5% and 1–3%, respectively. If desired, other elements are added to the melt before the final form is produced by casting. Cast iron is sometimes melted in a special type of blast furnace known as a cupola, but in modern applications, it is more melted in electric induction furnaces or electric arc furnaces. After melting is complete, the molten cast iron is poured into ladle. Cast iron's properties alloyants. Next to carbon, silicon is the most important alloyant. A low percentage of silicon allows carbon to remain in solution forming iron carbide and the production of white cast iron.
A high percentage of silicon forces carbon out of solution forming graphite and the production of grey cast iron. Other alloying agents, chromium, molybdenum and vanadium counteracts silicon, promotes the retention of carbon, the formation of those carbides. Nickel and copper increase strength, machinability, but do not change the amount of graphite formed; the carbon in the form of graphite results in a softer iron, reduces shrinkage, lowers strength, decreases density. Sulfur a contaminant when present, forms iron sulfide, which prevents the formation of graphite and increases hardness; the problem with sulfur is. To counter the effects of sulfur, manganese is added because the two form into manganese sulfide instead of iron sulfide; the manganese sulfide is lighter than the melt, so it tends to float out of the melt and into the slag. The amount of manganese required to neutralize sulfur is 1.7 × sulfur content + 0.3%. If more than this amount of manganese is added manganese carbide forms, which increases hardness and chilling, except in grey iron, where up to 1% of manganese increases strength and density.
Nickel is one of the most common alloying elements because it refines the pearlite and graphite structure, improves toughness, evens out hardness differences between section thicknesses. Chromium is added in small amounts to reduce free graphite, produce chill, because it is a powerful carbide stabilizer. A small amount of tin can be added as a substitute for 0.5% chromium. Copper is added in the ladle or in the furnace, on the order of 0.5–2.5%, to decrease chill, refine graphite, increase fluidity. Molybdenum is added on the order of 0.3–1% to increase chill and refine the graphite and pearlite structure. Titanium is added as a degasser and deoxidizer, but it increases fluidity. 0.15–0.5% vanadium is added to cast iron to stabilize cementite, increase hardness, increase resistance to wear and heat. 0.1–0.3% zirconium helps to form graphite and increase fluidity. In malleable iron melts, bismuth is added, on the scale of 0.002–0.01%, to increase how much silicon can be added. In white iron, boron is added to aid in the production of malleable iron.
The Mississippi River is the second-longest river and chief river of the second-largest drainage system on the North American continent, second only to the Hudson Bay drainage system. Its source is Lake Itasca in northern Minnesota and it flows south for 2,320 miles to the Mississippi River Delta in the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 32 U. S. two Canadian provinces between the Rocky and Appalachian mountains. The main stem is within the United States; the Mississippi ranks as the fifteenth-largest river by discharge in the world. The river either borders or passes through the states of Minnesota, Iowa, Missouri, Tennessee, Arkansas and Louisiana. Native Americans have lived along its tributaries for thousands of years. Most were hunter-gatherers, but some, such as the Mound Builders, formed prolific agricultural societies; the arrival of Europeans in the 16th century changed the native way of life as first explorers settlers, ventured into the basin in increasing numbers.
The river served first as a barrier, forming borders for New Spain, New France, the early United States, as a vital transportation artery and communications link. In the 19th century, during the height of the ideology of manifest destiny, the Mississippi and several western tributaries, most notably the Missouri, formed pathways for the western expansion of the United States. Formed from thick layers of the river's silt deposits, the Mississippi embayment is one of the most fertile regions of the United States. During the American Civil War, the Mississippi's capture by Union forces marked a turning point towards victory, due to the river's strategic importance to the Confederate war effort; because of substantial growth of cities and the larger ships and barges that replaced steamboats, the first decades of the 20th century saw the construction of massive engineering works such as levees and dams built in combination. A major focus of this work has been to prevent the lower Mississippi from shifting into the channel of the Atchafalaya River and bypassing New Orleans.
Since the 20th century, the Mississippi River has experienced major pollution and environmental problems – most notably elevated nutrient and chemical levels from agricultural runoff, the primary contributor to the Gulf of Mexico dead zone. The word Mississippi itself comes from Misi zipi, the French rendering of the Anishinaabe name for the river, Misi-ziibi. In the 18th century, the river was the primary western boundary of the young United States, since the country's expansion westward, the Mississippi River has been considered a convenient if approximate dividing line between the Eastern and Midwestern United States, the Western United States; this is exemplified by the Gateway Arch in St. Louis and the phrase "Trans-Mississippi" as used in the name of the Trans-Mississippi Exposition, it is common to qualify a regionally superlative landmark in relation to it, such as "the highest peak east of the Mississippi" or "the oldest city west of the Mississippi". The FCC uses it as the dividing line for broadcast call-signs, which begin with W to the east and K to the west, mixing together in media markets along the river.
The Mississippi River can be divided into three sections: the Upper Mississippi, the river from its headwaters to the confluence with the Missouri River. The Upper Mississippi runs from its headwaters to its confluence with the Missouri River at St. Louis, Missouri, it is divided into two sections: The headwaters, 493 miles from the source to Saint Anthony Falls in Minneapolis, Minnesota. The source of the Upper Mississippi branch is traditionally accepted as Lake Itasca, 1,475 feet above sea level in Itasca State Park in Clearwater County, Minnesota; the name "Itasca" was chosen to designate the "true head" of the Mississippi River as a combination of the last four letters of the Latin word for truth and the first two letters of the Latin word for head. However, the lake is in turn fed by a number of smaller streams. From its origin at Lake Itasca to St. Louis, the waterway's flow is moderated by 43 dams. Fourteen of these dams are located above Minneapolis in the headwaters region and serve multiple purposes, including power generation and recreation.
The remaining 29 dams, beginning in downtown Minneapolis, all contain locks and were constructed to improve commercial navigation of the upper river. Taken as a whole, these 43 dams shape the geography and influence the ecology of the upper river. Beginning just below Saint Paul and continuing throughout the upper and lower river, the Mississippi is further controlled by thousands of wing dikes that moderate the river's flow in order to maintain an open navigation channel and prevent the river from eroding its banks; the head of navigation on the Mississippi is the Coon Rapids Dam in Minnesota. Before it was built in 1913, steamboats could go upstream as far as Saint Cloud, depending on river conditions; the uppermost lock and dam on the Upper Mississippi River is the Upper St. Anthony Falls Lock an