Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are rich in iron oxides and vary in colour from dark grey, bright yellow, or deep purple to rusty red; the iron is found in the form of magnetite, goethite, limonite or siderite. Ores containing high quantities of hematite or magnetite are known as "natural ore" or "direct shipping ore", meaning they can be fed directly into iron-making blast furnaces. Iron ore is the raw material used to make pig iron, one of the main raw materials to make steel—98% of the mined iron ore is used to make steel. Indeed, it has been argued that iron ore is "more integral to the global economy than any other commodity, except oil". Metallic iron is unknown on the surface of the Earth except as iron-nickel alloys from meteorites and rare forms of deep mantle xenoliths. Although iron is the fourth most abundant element in the Earth's crust, comprising about 5%, the vast majority is bound in silicate or more carbonate minerals.
The thermodynamic barriers to separating pure iron from these minerals are formidable and energy intensive, therefore all sources of iron used by human industry exploit comparatively rarer iron oxide minerals hematite. Prior to the industrial revolution, most iron was obtained from available goethite or bog ore, for example during the American Revolution and the Napoleonic Wars. Prehistoric societies used laterite as a source of iron ore. Much of the iron ore utilized by industrialized societies has been mined from predominantly hematite deposits with grades of around 70% Fe; these deposits are referred to as "direct shipping ores" or "natural ores". Increasing iron ore demand, coupled with the depletion of high-grade hematite ores in the United States, after World War II led to development of lower-grade iron ore sources, principally the utilization of magnetite and taconite. Iron-ore mining methods vary by the type of ore being mined. There are four main types of iron-ore deposits worked depending on the mineralogy and geology of the ore deposits.
These are magnetite, massive hematite and pisolitic ironstone deposits. Banded iron formations are sedimentary rocks containing more than 15% iron composed predominantly of thinly bedded iron minerals and silica. Banded iron formations occur in Precambrian rocks, are weakly to intensely metamorphosed. Banded iron formations may contain iron in carbonates or silicates, but in those mined as iron ores, oxides are the principal iron mineral. Banded iron formations are known as taconite within North America; the mining involves moving tremendous amounts of waste. The waste comes in two forms, non-ore bedrock in the mine, unwanted minerals which are an intrinsic part of the ore rock itself; the mullock is mined and piled in waste dumps, the gangue is separated during the beneficiation process and is removed as tailings. Taconite tailings are the mineral quartz, chemically inert; this material is stored in regulated water settling ponds. The key economic parameters for magnetite ore being economic are the crystallinity of the magnetite, the grade of the iron within the banded iron formation host rock, the contaminant elements which exist within the magnetite concentrate.
The size and strip ratio of most magnetite resources is irrelevant as a banded iron formation can be hundreds of meters thick, extend hundreds of kilometers along strike, can come to more than three billion or more tonnes of contained ore. The typical grade of iron at which a magnetite-bearing banded iron formation becomes economic is 25% iron, which can yield a 33% to 40% recovery of magnetite by weight, to produce a concentrate grading in excess of 64% iron by weight; the typical magnetite iron-ore concentrate has less than 0.1% phosphorus, 3–7% silica and less than 3% aluminium. Magnetite iron ore is mined in Minnesota and Michigan in the U. S. Eastern Canada and Northern Sweden. Magnetite bearing banded iron formation is mined extensively in Brazil, which exports significant quantities to Asia, there is a nascent and large magnetite iron-ore industry in Australia. Direct-shipping iron-ore deposits are exploited on all continents except Antarctica, with the largest intensity in South America and Asia.
Most large hematite iron-ore deposits are sourced from altered banded iron formations and igneous accumulations. DSO deposits are rarer than the magnetite-bearing BIF or other rocks which form its main source or protolith rock, but are cheaper to mine and process as they require less beneficiation due to the higher iron content. However, DSO ores can contain higher concentrations of penalty elements being higher in phosphorus, water content and aluminum. Export grade DSO ores are in the 62–64% Fe range. Granite and ultrapotassic igneous rocks segregate magnetite crystals and form masses of magnetite suitable for economic concentration. A few iron ore deposits, notably in Chile, are formed from volcanic flows containing significant accumulations of magnetite phenocrysts. Chilean magnetite iron ore deposits within the Atacama Desert have formed alluvial accumulations of magnetite in s
2010 United States Census
The 2010 United States Census is the twenty-third and most recent United States national census. National Census Day, the reference day used for the census, was April 1, 2010; the census was taken via mail-in citizen self-reporting, with enumerators serving to spot-check randomly selected neighborhoods and communities. As part of a drive to increase the count's accuracy, 635,000 temporary enumerators were hired; the population of the United States was counted as 308,745,538, a 9.7% increase from the 2000 Census. This was the first census in which all states recorded a population of over half a million, as well as the first in which all 100 largest cities recorded populations of over 200,000; as required by the United States Constitution, the U. S. census has been conducted every 10 years since 1790. The 2000 U. S. Census was the previous census completed. Participation in the U. S. Census is required by law in Title 13 of the United States Code. On January 25, 2010, Census Bureau Director Robert Groves inaugurated the 2010 Census enumeration by counting World War II veteran Clifton Jackson, a resident of Noorvik, Alaska.
More than 120 million census forms were delivered by the U. S. Post Office beginning March 15, 2010; the number of forms mailed out or hand-delivered by the Census Bureau was 134 million on April 1, 2010. Although the questionnaire used April 1, 2010 as the reference date as to where a person was living, an insert dated March 15, 2010 included the following printed in bold type: "Please complete and mail back the enclosed census form today." The 2010 Census national mail participation rate was 74%. From April through July 2010, census takers visited households that did not return a form, an operation called "non-response follow-up". In December 2010, the U. S. Census Bureau delivered population information to the U. S. President for apportionment, in March 2011, complete redistricting data was delivered to states. Identifiable information will be available in 2082; the Census Bureau did not use a long form for the 2010 Census. In several previous censuses, one in six households received this long form, which asked for detailed social and economic information.
The 2010 Census used only a short form asking ten basic questions: How many people were living or staying in this house, apartment, or mobile home on April 1, 2010? Were there any additional people staying here on April 1, 2010 that you did not include in Question 1? Mark all that apply: Is this house, apartment, or mobile home – What is your telephone number? What is Person 1's name? What is Person 1's sex? What is Person 1's age and Person 1's date of birth? Is Person 1 of Hispanic, Latino, or Spanish origin? What is Person 1's race? Does Person 1 sometimes live or stay somewhere else? The form included space to repeat all of these questions for up to twelve residents total. In contrast to the 2000 census, an Internet response option was not offered, nor was the form available for download. Detailed socioeconomic information collected during past censuses will continue to be collected through the American Community Survey; the survey provides data about communities in the United States on a 1-year or 3-year cycle, depending on the size of the community, rather than once every 10 years.
A small percentage of the population on a rotating basis will receive the survey each year, no household will receive it more than once every five years. In June 2009, the U. S. Census Bureau announced. However, the final form did not contain a separate "same-sex married couple" option; when noting the relationship between household members, same-sex couples who are married could mark their spouses as being "Husband or wife", the same response given by opposite-sex married couples. An "unmarried partner" option was available for couples; the 2010 census cost $13 billion $42 per capita. Operational costs were $5.4 billion under the $7 billion budget. In December 2010 the Government Accountability Office noted that the cost of conducting the census has doubled each decade since 1970. In a detailed 2004 report to Congress, the GAO called on the Census Bureau to address cost and design issues, at that time, had estimated the 2010 Census cost to be $11 billion. In August 2010, Commerce Secretary Gary Locke announced that the census operational costs came in under budget.
Locke credited the management practices of Census Bureau director Robert Groves, citing in particular the decision to buy additional advertising in locations where responses lagged, which improved the overall response rate. The agency has begun to rely more on questioning neighbors or other reliable third parties when a person could not be reached at home, which reduced the cost of follow-up visits. Census data for about 22% of U. S. househol
David Crockett State Park
Not to be confused with Davy Crockett Birthplace State Park in Greene County, Tennessee. David Crockett State Park is a state park in Tennessee; the park is located on Shoal Creek called the. And commemorates the historical activities of famous frontiersman David Crockett in the local area. Crockett settled near the creek bank in 1817 and started a powder mill, grist mill and distillery using the creek's water power. By 1820, he owned 614 acres of land at Shoal Creek, he served as one of Lawrence County's first commissioners and justices of the peace. After his industrial operations were destroyed by a flood in September 1821, Crockett left the area and moved to West Tennessee; the park was established in 1959 on 1,100 acres of land that includes the site where Crockett had his mills and distillery. Park facilities include reconstructions of a mill. A historical museum in the park, open during the summer months, is focused on Crockett's life. A covered bridge built across Shoal Creek in 1959 was destroyed by flooding in 1998 and replaced the following year.
A 40-acre lake offers opportunities for boating. Visitor facilities include a restaurant. Seven two-bedroom visitor cabins built in the park in 2010 were the first vacation homes in a U. S. state park to receive LEED Silver certification from the U. S. Green Building Council. Official website
Tornado outbreak of April 15–16, 1998
The April 15–16, 1998 tornado outbreak was a two-day tornado outbreak that affected portions of the Midwestern United States and Tennessee Valleys on April 15 and April 16, 1998, with the worst of the outbreak taking place on the second day. On that day, 13 tornadoes swept through Middle Tennessee—two of them touching down in Nashville, causing significant damage to the downtown and East Nashville areas. Nashville became the first major city in nearly 20 years to have an F2 or larger tornado make a direct hit in the downtown area. In addition, the outbreak produced several other destructive tornadoes in Middle Tennessee. One of them, southwest of Nashville, was an F5 tornado—one of only two recorded in the state; that tornado remained in rural areas of Wayne and Lawrence counties. Other tornadoes during the 2-day outbreak struck Arkansas, Alabama and Kentucky. 12 people were killed by tornadoes during the outbreak: two in Arkansas, three in Kentucky, seven in Tennessee. This tornado outbreak occurred at the end of the record-setting 1997–1998 El Niño event.
One week after the Birmingham tornado outbreak took place across Alabama and Georgia on April 8–9, 1998 and several other states on April 7, a similar pattern developed across the Midwest and southeastern United States starting on April 16, 1998. A strong low pressure system developed across the central part of North America and was associated with a long cold front. Ahead of the storm, the warm moist air generated from the Gulf of Mexico increased the likelihood for a significant weather event. On April 15, activity developed across the Mid-Mississippi Valley and southern Ohio Valley where several tornadoes touched down in Illinois starting in the late afternoon before moving into Arkansas during the overnight hours where the first fatalities were reported. On April 16, as the main low-pressure system was near the Great Lakes and its cold front crossing the Mississippi River, dew points reached the mid to upper 60s across the Tennessee Valley while in the day, CAPE values reached 1600 J/kg while dry air intrusion was on the rise increasing the threat of severe weather across the area.
As the bulk of the supercells moved out of Arkansas, the tornadic activity was slower during the morning hours before re-intensifying west of Nashville early in the afternoon. Major tornadoes struck from southern Tennessee to southern Kentucky with additional storms as far north as Michigan and several other storms in Alabama across Walker and Cullman Counties, north of the areas that were hardest hit by the previous outbreak; this tornado, rated F3, touched down near the intersection of Charlotte Pike and Forty-Sixth Avenue and traveled directly through downtown Nashville. The tornado manifested itself as a large area of rotating rain curtains and dark clouds, rather than a traditional funnel. After crossing the Cumberland River, it passed through East Nashville and Hermitage before lifting northwest of Lebanon in extreme northern Wilson County. An ROTC student from Vanderbilt University was trapped under a fallen tree in Centennial Park and died from his injuries; the tornado blew many windows out of office buildings.
Many large buildings, including skyscrapers, were damaged. The TPAC building had over 100 windows blown out. 30 small airplanes were damaged at Cornelia Fort Airport. 35 total buildings in downtown Nashville were deemed structurally unsound after the tornado. The tornado blew down 3 construction cranes on the construction site of the Tennessee Oilers' football stadium near the Cumberland River, before crossing the river. Many signs were downed throughout downtown as well; the tornado hit the residential section of East Nashville. At least 300 homes were damaged in East Nashville, many of which lost a good part of their roofs, with a few destroyed. Trees were uprooted and telephone poles were knocked down in this area. A nursing home was hit and all the residents had to be evacuated. A church, well over 100 years old, received major damage, it re-crossed the Cumberland River, where more trees were downed and more homes and other buildings were damaged across Donelson and Hermitage. Over a thousand trees were blown down at The Hermitage.
Some of those trees were well over 200 years old, with a few having been planted by Andrew Jackson himself. The tornado moved into Wilson County, downing many trees, power lines, signs. Several homes suffered roof damage in the area. A baseball field and a lumber yard were damaged in Mt. Juliet. Part of the roof was taken off a bank in Mt. Juliet as well; the tornado continued across rural Wilson County and produced sporadic damage before it dissipated just south of the Cumberland River in extreme northern Wilson County. No fatalities were reported with this F5 wedge tornado as it touched down just inside Wayne County and traveled through sparsely populated areas of Lawrence County and northwest of Lawrenceburg. There were 21 injuries, however, it did not affect any towns along its 19.3 miles path. However, many large and well-built homes with anchor bolts were leveled with some swept clean from their foundations, vehicles were thrown hundreds of yards. One truck was rumored to have been taken about 20 miles.
A 200-foot section of grass was scoured away at a pasture. Clumps of dirt were pulled up as well. Many trees and power lines were downed as well as 75 utility poles; some of the trees were debarked, several livestock were killed as well. It i
A county seat is an administrative center, seat of government, or capital city of a county or civil parish. The term is used in Canada, Romania and the United States. County towns have a similar function in the United Kingdom and Republic of Ireland, in Jamaica. In most of the United States, counties are the political subdivisions of a state; the city, town, or populated place that houses county government is known as the seat of its respective county. The county legislature, county courthouse, sheriff's department headquarters, hall of records and correctional facility are located in the county seat though some functions may be located or conducted in other parts of the county if it is geographically large. A county seat is but not always, an incorporated municipality; the exceptions include the county seats of counties that have no incorporated municipalities within their borders, such as Arlington County, Virginia. Ellicott City, the county seat of Howard County, is the largest unincorporated county seat in the United States, followed by Towson, the county seat of Baltimore County, Maryland.
Some county seats may not be incorporated in their own right, but are located within incorporated municipalities. For example, Cape May Court House, New Jersey, though unincorporated, is a section of Middle Township, an incorporated municipality. In some of the colonial states, county seats include or included "Court House" as part of their name. In the Canadian provinces of Prince Edward Island, New Brunswick, Nova Scotia, the term "shire town" is used in place of county seat. County seats in Taiwan are the administrative centers of the counties. There are 13 county seats in Taiwan, which are in the forms of county-administered city, urban township or rural township. Most counties have only one county seat. However, some counties in Alabama, Georgia, Kentucky, Mississippi, New Hampshire, New York, Vermont have two or more county seats located on opposite sides of the county. An example is Harrison County, which lists both Biloxi and Gulfport as county seats; the practice of multiple county seat towns dates from the days.
There have been few efforts to eliminate the two-seat arrangement, since a county seat is a source of pride for the towns involved. There are 36 counties with multiple county seats in 11 states: Coffee County, Alabama St. Clair County, Alabama Arkansas County, Arkansas Carroll County, Arkansas Clay County, Arkansas Craighead County, Arkansas Franklin County, Arkansas Logan County, Arkansas Mississippi County, Arkansas Prairie County, Arkansas Sebastian County, Arkansas Yell County, Arkansas Columbia County, Georgia Lee County, Iowa Campbell County, Kentucky Kenton County, Kentucky Essex County, Massachusetts Middlesex County, Massachusetts Plymouth County, Massachusetts Bolivar County, Mississippi Carroll County, Mississippi Chickasaw County, Mississippi Harrison County, Mississippi Hinds County, Mississippi Jasper County, Mississippi Jones County, Mississippi Panola County, Mississippi Tallahatchie County, Mississippi Yalobusha County, Mississippi Jackson County, Missouri Hillsborough County, New Hampshire Seneca County, New York Bennington County, Vermont In New England, the town, not the county, is the primary division of local government.
Counties in this region have served as dividing lines for the states' judicial systems. Connecticut and Rhode Island have no county level of thus no county seats. In Vermont and Maine the county seats are designated shire towns. County government consists only of a Superior Court and Sheriff, both located in the respective shire town. Bennington County has two shire towns. In Massachusetts, most government functions which would otherwise be performed by county governments in other states are performed by town or city governments; as such, Massachusetts has dissolved many of its county governments, the state government now operates the registries of deeds and sheriff's offices in those counties. In Virginia, a county seat may be an independent city surrounded by, but not part of, the county of which it is the administrative center. Two counties in South Dakota have their county seat and government services centered in a neighboring county, their county-level services are provided by Fall River Tripp County, respectively.
In Louisiana, divided into parishes rather than counties, county seats are referred to as parish seats. Alaska is divided into boroughs rather than counties; the Unorganized Borough, which covers 49 % of Alaska's area, has equivalent. The state with the most counties is Texas, with 254, the state with the fewest counties is Delaware, with 3. County seat war Administrative center County town, administrative centres in Ireland and the UK Chef-lieu, administrative centres in Algeria, Luxembourg, France and Tunisia Municipality, equivalent to county in many c
The United States of America known as the United States or America, is a country composed of 50 states, a federal district, five major self-governing territories, various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is smaller than the entire continent of Europe's 3.9 million square miles. With a population of over 327 million people, the U. S. is the third most populous country. The capital is Washington, D. C. and the largest city by population is New York City. Forty-eight states and the capital's federal district are contiguous in North America between Canada and Mexico; the State of Alaska is in the northwest corner of North America, bordered by Canada to the east and across the Bering Strait from Russia to the west. The State of Hawaii is an archipelago in the mid-Pacific Ocean; the U. S. territories are scattered about the Pacific Ocean and the Caribbean Sea, stretching across nine official time zones. The diverse geography and wildlife of the United States make it one of the world's 17 megadiverse countries.
Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago. European colonization began in the 16th century; the United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies following the French and Indian War led to the American Revolution, which began in 1775, the subsequent Declaration of Independence in 1776; the war ended in 1783 with the United States becoming the first country to gain independence from a European power. The current constitution was adopted in 1788, with the first ten amendments, collectively named the Bill of Rights, being ratified in 1791 to guarantee many fundamental civil liberties; the United States embarked on a vigorous expansion across North America throughout the 19th century, acquiring new territories, displacing Native American tribes, admitting new states until it spanned the continent by 1848. During the second half of the 19th century, the Civil War led to the abolition of slavery.
By the end of the century, the United States had extended into the Pacific Ocean, its economy, driven in large part by the Industrial Revolution, began to soar. The Spanish–American War and World War I confirmed the country's status as a global military power; the United States emerged from World War II as a global superpower, the first country to develop nuclear weapons, the only country to use them in warfare, a permanent member of the United Nations Security Council. Sweeping civil rights legislation, notably the Civil Rights Act of 1964, the Voting Rights Act of 1965 and the Fair Housing Act of 1968, outlawed discrimination based on race or color. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 U. S. Moon landing; the end of the Cold War and the collapse of the Soviet Union in 1991 left the United States as the world's sole superpower. The United States is the world's oldest surviving federation, it is a representative democracy.
The United States is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States, other international organizations. The United States is a developed country, with the world's largest economy by nominal GDP and second-largest economy by PPP, accounting for a quarter of global GDP; the U. S. economy is post-industrial, characterized by the dominance of services and knowledge-based activities, although the manufacturing sector remains the second-largest in the world. The United States is the world's largest importer and the second largest exporter of goods, by value. Although its population is only 4.3% of the world total, the U. S. holds 31% of the total wealth in the world, the largest share of global wealth concentrated in a single country. Despite wide income and wealth disparities, the United States continues to rank high in measures of socioeconomic performance, including average wage, human development, per capita GDP, worker productivity.
The United States is the foremost military power in the world, making up a third of global military spending, is a leading political and scientific force internationally. In 1507, the German cartographer Martin Waldseemüller produced a world map on which he named the lands of the Western Hemisphere America in honor of the Italian explorer and cartographer Amerigo Vespucci; the first documentary evidence of the phrase "United States of America" is from a letter dated January 2, 1776, written by Stephen Moylan, Esq. to George Washington's aide-de-camp and Muster-Master General of the Continental Army, Lt. Col. Joseph Reed. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort; the first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776. The second draft of the Articles of Confederation, prepared by John Dickinson and completed by June 17, 1776, at the latest, declared "The name of this Confederation shall be the'United States of America'".
The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence; this draft of the document did not surface unti
Distillation is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation. Distillation may result in complete separation, or it may be a partial separation that increases the concentration of selected components in the mixture. In either case, the process exploits differences in the volatility of the mixture's components. In industrial chemistry, distillation is a unit operation of universal importance, but it is a physical separation process, not a chemical reaction. Distillation has many applications. For example: Distillation of fermented products produces distilled beverages with a high alcohol content or separates out other fermentation products of commercial value. Distillation is an traditional method of desalination. In the fossil fuel industry, oil stabilization is a form of partial distillation that reduces vapor pressure of crude oil, thereby making it safe for storage and transport as well as reducing the atmospheric emissions of volatile hydrocarbons.
In midstream operations at oil refineries, distillation is a major class of operation for transforming crude oil into fuels and chemical feed stocks. Cryogenic distillation leads to the separation of air into its components – notably oxygen and argon – for industrial use. In the field of industrial chemistry, large amounts of crude liquid products of chemical synthesis are distilled to separate them, either from other products, from impurities, or from unreacted starting materials. An installation used for distillation of distilled beverages, is called a distillery; the distillation equipment at a distillery is a still. In 1975 Paolo Rovesti a chemist and pharmacist who became known as"father of Phytocosmetics" discovered a terracota distillation apparatus in the Indus valley in West Pakistan which dates from around 3000 BC. Early evidence of distillation was found on Akkadian tablets dated circa 1200 BC describing perfumery operations; the tablets provided textual evidence that an early primitive form of distillation was known to the Babylonians of ancient Mesopotamia.
Early evidence of distillation was found related to alchemists working in Alexandria in Roman Egypt in the 1st century. Distilled water has been in use since at least c. 200, when Alexander of Aphrodisias described the process. Work on distilling other liquids continued in early Byzantine Egypt under Zosimus of Panopolis in the 3rd century. Distillation was practiced in the ancient Indian subcontinent, evident from baked clay retorts and receivers found at Taxila and Charsadda in modern Pakistan, dating back to the early centuries of the Common Era; these "Gandhara stills" were only capable of producing weak liquor, as there was no efficient means of collecting the vapors at low heat. Distillation in China may have begun during the Eastern Han dynasty, but the distillation of beverages began in the Jin and Southern Song dynasties, according to archaeological evidence. Clear evidence of the distillation of alcohol comes from the Arab chemist Al-Kindi in 9th-century Iraq; the process spread to Italy, where it was described by the School of Salerno in the 12th century.
Fractional distillation was developed by Tadeo Alderotti in the 13th century. A still was found in an archaeological site in Qinglong, Hebei province, in China, dating back to the 12th century. Distilled beverages were common during the Yuan dynasty. In 1500, German alchemist Hieronymus Braunschweig published Liber de arte destillandi, the first book dedicated to the subject of distillation, followed in 1512 by a much expanded version. In 1651, John French published The Art of Distillation, the first major English compendium on the practice, but it has been claimed that much of it derives from Braunschweig's work; this includes diagrams with people in them showing the industrial rather than bench scale of the operation. As alchemy evolved into the science of chemistry, vessels called retorts became used for distillations. Both alembics and retorts are forms of glassware with long necks pointing to the side at a downward angle to act as air-cooled condensers to condense the distillate and let it drip downward for collection.
Copper alembics were invented. Riveted joints were kept tight by using various mixtures, for instance a dough made of rye flour; these alembics featured a cooling system around the beak, using cold water, for instance, which made the condensation of alcohol more efficient. These were called pot stills. Today, the retorts and pot stills have been supplanted by more efficient distillation methods in most industrial processes. However, the pot still is still used for the elaboration of some fine alcohols, such as cognac, Scotch whisky, Irish whiskey and some vodkas. Pot stills made of various materials are used by bootleggers in various countries. Small pot stills are sold for use in the domestic production of flower water or essential oils. Early forms of distillation involved batch processes using one condensation. Purity was improved by further distillation of the condensate. Greater volumes were processed by repeating the distillation. Chemists carried out as many as 500 to 600 distillations in order to obtain a pure compound.
In the early 19th century, the basics of modern techniques, including pre-heating and reflux, were developed. In 1822, Anthony Perrier developed one of the first continuous stills, in 1826, Robert Stein improved that design to make his patent still. In 1830, Aeneas Coffey got a patent for improving the design f