flint clay: see fire clay.

fire clay, clay that has a high degree of resistance to heat. By the best standards it should have a fusion point higher than 1,600°C;. The term "fire clay" is commonly held to exclude kaolin and other refractory potter's clays. Fire clay should contain high percentages of silica and alumina, with as little as possible of such impurities as lime, magnesia, soda, and potash, which lower the fusion point of the clay. Fire clay often forms the bed layer of earth under seams of coal. Two types are recognized—flint clay, exceedingly hard, nonplastic, and resembling flint in appearance, occurring in the United States; and plastic fire clay. The principal uses of fire clay are in the manufacture of firebrick and of various accessory utensils, such as crucibles, saggers, retorts, and glass pots, used in the metalworking industries.

clay pan: see hardpan.

clay, common name for a number of fine-grained, earthy materials that become plastic when wet. Chemically, clays are hydrous aluminum silicates, ordinarily containing impurities, e.g., potassium, sodium, calcium, magnesium, or iron, in small amounts.

Properties and Classification

Properties of the clays include plasticity, shrinkage under firing and under air drying, fineness of grain, color after firing, hardness, cohesion, and capacity of the surface to take decoration. On the basis of such qualities clays are variously divided into classes or groups; products are generally made from mixtures of clays and other substances. The purest clays are the china clays and kaolins. "Ball clay" is a name for a group of plastic, refractory (high-temperature) clays used with other clays to improve their plasticity and to increase their strength. Bentonites are clays composed of very fine particles derived usually from volcanic ash. They are composed chiefly of the hydrous magnesium-calcium-aluminum silicate called montmorillonite. See also fuller's earth.

Individual clay particles are always smaller than 0.004 mm. Clays often form colloidal suspensions when immersed in water, but the clay particles flocculate (clump) and settle quickly in saline water. Clays are easily molded into a form that they retain when dry, and they become hard and lose their plasticity when subjected to heat.

Formation

Clays are divided into two classes: residual clay, found in the place of origin, and transported clay, also known as sedimentary clay, removed from the place of origin by an agent of erosion and deposited in a new and possibly distant position. Residual clays are most commonly formed by surface weathering, which gives rise to clay in three ways—by the chemical decomposition of rocks, such as granite, containing silica and alumina; by the solution of rocks, such as limestone, containing clayey impurities, which, being insoluble, are deposited as clay; and by the disintegration and solution of shale. One of the commonest processes of clay formation is the chemical decomposition of feldspar.

Clay consists of a sheet of interconnected silicates combined with a second sheetlike grouping of metallic atoms, oxygen, and hydroxyl, forming a two-layer mineral such as kaolinite. Sometimes the latter sheetlike structure is found sandwiched between two silica sheets, forming a three-layer mineral such as vermiculite. In the lithification process, compacted clay layers can be transformed into shale. Under the intense heat and pressure that may develop in the layers, the shale can be metamorphosed into slate.

Uses

From prehistoric times, clay has been indispensable in architecture, in industry, and in agriculture. As a building material, it is used in the form of brick, either sun-dried (adobe) or fired. Clays are also of great industrial importance, e.g., in the manufacture of tile for wall and floor coverings, of porcelain, china, and earthenware, and of pipe for drainage and sewage. Highly absorbent, bentonite is much used in foundry work for facing the molds and preparing the molding sands for casting metals. The less absorbent bentonites are used chiefly in the oil industry, e.g., as filtering and deodorizing agents in the refining of petroleum and, mixed with other materials, as drilling muds to protect the cutting bit while drilling. Other uses are in the making of fillers, sizings, and dressings in construction, in clarifying water and wine, in purifying sewage, and in the paper, ceramics, plastics, and rubber industries.

Clay as a Soil

Clay is one of the three principal types of soil, the other two being sand and loam. A certain amount of clay is a desirable constituent of soil, since it binds other kinds of particles together and makes the whole retentive of water. Excessively clayey soils, however, are exceedingly difficult to cultivate. Their stiffness presents resistance to implements, impedes the growth of the plants, and prevents free circulation of air around the roots. They are cold and sticky in wet weather, while in dry weather they bake hard and crack. Clods form very often in clayey soils. Clays can be improved by the addition of lime, chalk, or organic matter; sodium nitrate, however, intensifies the injurious effects. In spite of their disadvantages, the richness of clay soils makes them favorable to the growth of crops that have been started in other soil.

china clay, one of the purest of the clays, composed chiefly of the mineral kaolinite usually formed when granite is changed by hydrothermal metamorphism. Usage of the terms china clay and kaolin is not well defined; sometimes they are used synonymously for a group of similar clays, and sometimes kaolin refers to those obtained in the United States and china clay to those that are imported. Some authorities term as china clays the more plastic of the kaolins. China clays have long been used in the ceramic industry, especially in fine porcelains, because they can be easily molded, have a fine texture, and are white when fired. France's clays are made into the famous Sèvres (see A. Brongniart) and Limoges potteries. These clays are also used as a filler in making paper. In the United States, deposits are found primarily in Georgia, North Carolina, and Pennsylvania; china clay is also mined in England (Cornwall) and France.

boulder clay: see drift.

Frick, Henry Clay, 1849-1919, American industrialist, b. Westmoreland co., Pa. He worked on his father's farm, was a store clerk, and did bookkeeping before he and several associates organized (1871) Frick & Company to operate coke ovens in the Connellsville coal district. He strengthened his position by buying out competitors during the Panic of 1873 and soon held a key place in the industry.

Andrew Carnegie, in order to control a business so vital to steelmaking, acquired heavy interests in Frick's organization. Frick, in turn, was given large holdings in the Carnegie company, and because of his managerial ability, he was made (1889) chairman of the steel company. He played a key role in the organization (1892) of the Carnegie Steel Company, and as its acting head Frick engineered a large expansion of the company by buying out competing companies and acquiring many holdings in railroad securities and in Lake Superior iron ore lands. Frick, frequently over Carnegie's protest, dealt in strong-handed fashion with the company's workers, and his adamant stand resulted in a pitched battle in the strike (1892) at Homestead, Pa.—one of the bitterest strikes in U.S. history (see Homestead strike). He was largely responsible for the antiunion policy that characterized the steel industry for many decades.

Disputes between Frick and Carnegie led to a struggle between them for control, and in 1899 Frick resigned. He became a director of the U.S. Steel Corp. and turned to other interests, chiefly railroads. His mansion in New York City, together with his art collection and endowment of $15 million, was willed to the public as a museum. Princeton Univ. and the city of Pittsburgh also benefited from his philanthropies.

Ford, William Clay, Jr.: see Bill Ford under Ford, Henry.

Folger, Henry Clay, 1857-1930, American industrialist and collector of Shakespeareana. His connection with Standard Oil companies, beginning in 1879, continued until his retirement 49 years later as chairman of the board of the New York company. He was an enthusiastic student of Shakespeare during his college days and became a discerning collector. His wife, Emily Jordan Folger (d. 1936), was his associate in this work. Their collection, quietly acquired, became one of the largest and most valuable of its sort in the world. The Folger Shakespeare Library, east of the Library of Congress, Washington, D.C., was dedicated in 1932. Its major collections contain more than 250,000 volumes, primarily 16th-and 17th-century works of literature, drama, and history of the English Renaissance. It is administered by Amherst College trustees.

Clay, Lucius DuBignon, 1897-1978, American general, b. Marietta, Ga. A graduate of West Point and an engineering officer, he held many army administrative posts and became (1944) deputy director of the office of War Mobilization and Reconversion. Clay was (1945-47) deputy chief of the U.S. military government in Germany and in 1947 became commander of U.S. troops in Europe. He directed operations in the Berlin blockade as U.S. military governor (1947-49). Clay retired from the army as a full general in May, 1949, to enter private business. After the closing of the borders between East and West Berlin by the Communists, he served (Sept., 1961-May, 1962) as President Kennedy's personal representative in Berlin with the rank of ambassador. He wrote Decision in Germany (1950).

Clay, Henry, 1777-1852, American statesman, b. Hanover co., Va.

Early Career

His father died when he was four years old, and Clay's formal schooling was limited to three years. His stepfather secured (1792) for him a clerk's position in the Virginia high court of chancery. There he gained the regard of George Wythe, who directed his reading. Clay also read law under Robert Brooke, attorney general of Virginia, and in 1797 he was licensed to practice.

Moving in the same year to Lexington, Ky., he quickly gained wide reputation as a lawyer and orator. He served (1803-6) in the Kentucky legislature and was (1805-7) professor of law at Transylvania Univ. Having spent the short session of 1806-7 in the U.S. Senate, he returned (1807) to the state legislature, became (1808) speaker, and remained there until he was chosen to fill an unexpired term (1810-11) in the U.S. Senate.

Congressman

In 1810 Clay was elected to the U.S. House of Representatives and served (1811-14) as speaker. As spokesman of Western expansionist interests and leader of the "war hawks," Clay stirred up enthusiasm for war with Great Britain and helped bring on the War of 1812. He resigned (1814) from Congress to aid in the peace negotiations leading to the Treaty of Ghent.

He again served (1815-21) in the House, again was speaker (1815-20), and began to formulate his "American system," a national program that ultimately included federal aid for internal improvements and tariff protection of American industries. In 1821, Clay, to pacify sectional interests, pushed the Missouri Compromise through the House. In the House for the last time (1823-25), he once more became (1823) speaker, and he did much to augment the powers of that office. In this session he secured the western extension of the National Road and, against much opposition, eloquently carried through the Tariff of 1824.

Secretary of State

As a candidate for the presidency in 1824, Clay had the fourth largest number of electoral votes, and, with no candidate having a majority, the election went to the House, where the three highest were to be voted upon. It became Clay's duty to vote for one of his rivals. Despite the Western interests of Andrew Jackson and despite the instructions of the Kentucky legislature to vote for him, Clay's dislike for the military hero was so intense that he voted for John Quincy Adams. When President Adams appointed Clay Secretary of State, Jackson's friends cried "corrupt bargain" and charged Clay with political collusion. Evidence has not been found to prove this, but the accusation impeded Clay's future political fortunes. As Secretary of State (1825-29), he secured congressional approval—which came too late for the American delegates to attend—of U.S. participation in the Pan-American Congress of 1826.

Senator

In 1828, Clay again supported Adams for President, and Jackson's success bitterly disappointed him. Although he intended to retire from politics, Clay was elected (1831) to the U.S. Senate and now led the National Republicans, who were beginning to call themselves Whigs (because they opposed Jackson's "tyranny"; see Whig party). Hoping to embarrass Jackson, Clay led the opposition in the Senate to the President's policies, but when the election came Jackson was overwhelmingly reelected.

Clay's chagrin was buried in the crisis developing over the tariff. South Carolina's nullification of the tariffs of 1828 and 1832 as well as Jackson's threats of armed invasion of that state allowed Clay to gain politically—working, even at the cost of his own protectionist views, toward a compromise with the John C. Calhoun faction, he helped to promote the Compromise Tariff of 1833.

Clay opposed the Jackson regime at every turn, particularly on the bank issue. When Jackson had the deposits removed (1833) from the Bank of the United States to his "pet banks," Clay secured in the Senate passage of a resolution—later expunged (Jan., 1837) from the record—censuring the President for his act.

Refusing to run for President in 1836, Clay continued his opposition tactics against Van Buren's administration and fought the subtreasury system in vain. In 1840, Clay lost the Whig nomination to William H. Harrison, mainly because of Thurlow Weed's adroit politics. Clay supported Harrison and, when Harrison was elected, was offered the post of Secretary of State, but he chose to stay in the Senate. He now planned to reestablish the Bank of the United States, but the unexpected accession of John Tyler to the presidency and his vetoes of Clay's bills caused Clay to resign his Senate seat.

In 1844 he ran against James K. Polk, an avowed expansionist. Earlier Clay had publicly opposed the annexation of Texas, and he restated his position in the "Alabama letters," agreeing to annexation if it could be accomplished with the common consent of the Union and without war. This maneuver probably lost him New York state, with which he could have won the election. His failure was crushing for him and for the Whig party. In 1848 his party refused him its nomination, feeling that he had no chance, and his presidential aspirations were never fulfilled.

He reentered (1849) the Senate when the country faced the slavery question in the territory newly acquired following the Mexican War. Clay denounced the extremists in both North and South, asserted the superior claims of the Union, and was chiefly instrumental in shaping the Compromise of 1850. It was the third time that he saved the Union in a crisis, and thus he has been called the Great Pacificator and the Great Compromiser.

Clay, Clement Claiborne, 1816-82, U.S. Senator (1853-61), b. Huntsville, Ala. A legislator and then a judge in his native state, he was twice elected to the U.S. Senate and became an ardent defender of the states' rights doctrine. He left the Senate upon Alabama's secession and entered the Confederate senate, refusing the appointment as Secretary of War in the Confederacy. In 1864 he was sent by Jefferson Davis with two others on a diplomatic mission to Canada, which was intended to open peace negotiations with the federal government. Lincoln finally decided not to see him, and after a year in Canada, Clay returned to the South. After the assassination of Lincoln, he was accused of having taken part in a plot in Canada against Lincoln's life and also of having planned raids across the border, and a reward was offered for him. He gave himself up, was held at Fortress Monroe for almost a year without trial, and then was freed. His wife, Virginia Clay-Clopton, wrote A Belle of the Fifties (1904), a description of their Washington, D.C., home when it was a gathering place of capital society.

Clay, Cassius Marcellus, Jr.: see Ali, Muhammad.

Clay, Cassius Marcellus, 1810-1903, American politician and diplomat, b. Madison co., Ky. Although he came from a slaveholding family, Clay early came to abhor the institution of slavery. In 1845 he established at Lexington, Ky., the True American, an abolitionist paper. His press was moved by his enemies to Cincinnati, and he continued its publication there and at Louisville. He served as a captain in the Mexican War and was captured and for a time imprisoned. In 1851 he was an unsuccessful candidate for governor of Kentucky on an antislavery ticket; he captured enough votes, however, to cause the defeat of the Whig candidate and thus hastened the collapse of the Whigs in Kentucky. He was minister to Russia (1861-62, 1863-69) and served briefly in the Civil War as a major general of volunteers.

or pan or flat or dry lake

Flat-bottomed depression that is periodically covered by water. Playas occur in interior desert basins and adjacent to coasts in arid and semiarid regions. The water that periodically covers the playa slowly filters into the groundwater system or evaporates into the atmosphere, causing the deposition of salt, sand, and mud along the bottom and around the edges of the depression.

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Any of a group of important hydrous aluminum silicates with a layered structure and very small (less than 0.005 mm or microscopic) particle size. They are usually the products of weathering. Clay minerals occur widely in such sedimentary rocks as mudstones and shales, in marine sediments, and in soils. Different geologic environments produce different clay minerals from the same parent rock. They are used in the petroleum industry (as drilling muds and as catalysts in refining) and in the processing of vegetable and mineral oils (as decolorizing agents).

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Soil particles with diameters less than 0.005 mm; also a material composed essentially of clay particles (see clay mineral). In soils, clays provide the environment for almost all plant growth. The use of clay in pottery making predates recorded human history. As building materials, clay bricks (baked and as adobe) have been used in construction since earliest times. Kaolin, or china clay, is required for the finer grades of ceramic materials; used for paper coating and filler, it gives the paper a gloss, permitting high-quality reproduction, and increases paper opacity. Clay materials have many uses in engineering; earth dams are made impermeable to water by a core of clay, and water loss in canals may be reduced by lining the bottom with clay (called puddling). The essential raw materials of portland cement include clays.

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In geology, the unsorted material deposited directly by glacial ice and showing no stratification. Till is sometimes called boulder clay because it is composed of clay, boulders of intermediate size, or both. The rock fragments are usually angular and sharp rather than rounded, because they are deposited from ice and have undergone little water transport. The pebbles and boulders may be faceted and striated from grinding while lodged in the glacier.

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or till-less agriculture

Cultivation technique in which the soil is disturbed only along the slit or hole into which seeds are planted. Reserved detritus from previous crops covers and protects the seedbed. Primary benefits are a decreased rate of soil erosion; reduced need for equipment, fuel, and fertilizer; and significantly less time required for tending crops. The method also improves soil-aggregate formation, microbial activity in the soil, and water infiltration and storage. Conventional tillage controls weed growth by plowing and cultivating, but no-till farming selectively uses herbicides to kill weeds and the remains of the previous crop. No-till farming is one of several primitive farming methods revived as conservation measures in the 20th century.

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German peasant trickster of folk and literary tales. The historical Till is said to have died in 1350; anecdotes associated with his name were printed circa 1500 in Low German and from 1515 in High German. In the tales the stupid yet cunning peasant demonstrates his superiority to the narrow, dishonest, condescending townsmen, as well as to the clergy and nobility. The tales were translated into Dutch and English (circa 1520), French (1532), and Latin (1558).

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(born April 23, 1897, Marietta, Ga., U.S.—died April 16, 1978, Cape Cod, Mass.) U.S. army officer. After graduating from West Point, he served in various military engineering assignments. In World War II he directed the U.S. Army procurement program (1942–44). In 1945 he was appointed deputy military governor of the U.S. zone of occupation in defeated Germany. Two years later he was elevated to commander in chief of U.S. forces in Europe and military governor of the U.S. zone. In 1948–49 he organized the successful Allied airlift of food and supplies into Berlin during the Soviet blockade of that city (see Berlin blockade and airlift). After retiring in 1949, he entered private business and became an unofficial adviser to Pres. Dwight D. Eisenhower.

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(born , Dec. 19, 1849, West Overton, Pa., U.S.—died Dec. 2, 1919, New York, N.Y.) U.S. industrialist. He began building and operating coke ovens in 1870 and organized his own company in 1871. From 1889 he served as chairman of Carnegie Steel Co., the world's largest manufacturer of steel and coke. His role in the violent steel strike of 1892 in Homestead, Pa., provoked an anarchist to shoot and stab him, but he survived. He was instrumental in the formation of the U.S. Steel Corp. in 1901. A noted art collector and philanthropist, he bequeathed the Frick Collection to New York City. Seealso Andrew Carnegie.

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(born April 12, 1777, Hanover county, Va., U.S.—died June 29, 1852, Washington, D.C.) U.S. politician. He practiced law from 1797 in Virginia and then in Kentucky, where he served in the state legislature (1803–09). He was elected to the U.S. House of Representatives (1811–14, 1815–21, 1823–25); as House speaker (1811–14), he was among those who propelled the U.S. into the War of 1812. He supported a national economic policy of protective tariffs, known as the American System, a national bank, and improvements to internal transportation. His support of the Missouri Compromise earned him the nicknames “The Great Pacificator” and “The Great Compromiser.” After his bid for the presidency in 1824 fell short, Clay threw his support to John Quincy Adams, who made him his secretary of state (1825–29). He served in the U.S. Senate (1806–07, 1810–11, and 1831–42), where he supported the compromise tariff of 1833. He was the National Republican Party candidate for president in 1832 and the Whig Party candidate in 1844. In his last Senate term (1849–52) he argued strongly for passage of the Compromise of 1850.

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(born , Dec. 19, 1849, West Overton, Pa., U.S.—died Dec. 2, 1919, New York, N.Y.) U.S. industrialist. He began building and operating coke ovens in 1870 and organized his own company in 1871. From 1889 he served as chairman of Carnegie Steel Co., the world's largest manufacturer of steel and coke. His role in the violent steel strike of 1892 in Homestead, Pa., provoked an anarchist to shoot and stab him, but he survived. He was instrumental in the formation of the U.S. Steel Corp. in 1901. A noted art collector and philanthropist, he bequeathed the Frick Collection to New York City. Seealso Andrew Carnegie.

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(born April 23, 1897, Marietta, Ga., U.S.—died April 16, 1978, Cape Cod, Mass.) U.S. army officer. After graduating from West Point, he served in various military engineering assignments. In World War II he directed the U.S. Army procurement program (1942–44). In 1945 he was appointed deputy military governor of the U.S. zone of occupation in defeated Germany. Two years later he was elevated to commander in chief of U.S. forces in Europe and military governor of the U.S. zone. In 1948–49 he organized the successful Allied airlift of food and supplies into Berlin during the Soviet blockade of that city (see Berlin blockade and airlift). After retiring in 1949, he entered private business and became an unofficial adviser to Pres. Dwight D. Eisenhower.

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(born April 12, 1777, Hanover county, Va., U.S.—died June 29, 1852, Washington, D.C.) U.S. politician. He practiced law from 1797 in Virginia and then in Kentucky, where he served in the state legislature (1803–09). He was elected to the U.S. House of Representatives (1811–14, 1815–21, 1823–25); as House speaker (1811–14), he was among those who propelled the U.S. into the War of 1812. He supported a national economic policy of protective tariffs, known as the American System, a national bank, and improvements to internal transportation. His support of the Missouri Compromise earned him the nicknames “The Great Pacificator” and “The Great Compromiser.” After his bid for the presidency in 1824 fell short, Clay threw his support to John Quincy Adams, who made him his secretary of state (1825–29). He served in the U.S. Senate (1806–07, 1810–11, and 1831–42), where he supported the compromise tariff of 1833. He was the National Republican Party candidate for president in 1832 and the Whig Party candidate in 1844. In his last Senate term (1849–52) he argued strongly for passage of the Compromise of 1850.

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orig. Cassius (Marcellus) Clay

(born Jan. 17, 1942, Louisville, Ken., U.S.) U.S. boxer. Cassius Clay took up boxing at the age of 12 and rose through the amateur ranks to win the Olympic light heavyweight crown in 1960. His first professional heavyweight h1 win was against Sonny Liston in 1964. After defending the h1 nine times between 1965 and 1967, he was stripped of it for refusing induction into the armed forces following his acceptance of the teachings of the Nation of Islam. It was then that he changed his name to Muhammad Ali. In 1974 Ali regained his h1 after defeating the former champion Joe Frazier and the then-current champion George Foreman. He lost to Leon Spinks in 1978 but later that year regained the h1 a third time, becoming the first heavyweight champion ever to do so. He retired in 1979, having lost only three of 59 fights. Attempted comebacks in 1980 and 1981 failed. Throughout his career Ali was known for his aggressive charm, invincible attitude, and colourful boasts, often expressed in doggerel verse. “I am the greatest” was his personal credo. Ali's later years have been marked by physical decline. Damage to his brain, caused by blows to the head, has resulted in slurred speech, slowed movement, and other symptoms of Parkinson disease.

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(born Oct. 19, 1810, Madison county, Ky., U.S.—died July 22, 1903, Whitehall, Ky.) U.S. abolitionist and politician. The son of a slaveholder and a relative of Henry Clay, he was strongly influenced by the abolitionist ideas of William Lloyd Garrison. In 1845 he founded the antislavery publication True American in Lexington, Ky., but he was forced by opponents to move it to Cincinnati, Ohio, and then to Louisville, Ky., where it was renamed The Examiner. He helped found the Republican Party in 1854. As U.S. minister to Russia (1861–62, 1863–69), he helped negotiate the Alaska Purchase.

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(born Oct. 19, 1810, Madison county, Ky., U.S.—died July 22, 1903, Whitehall, Ky.) U.S. abolitionist and politician. The son of a slaveholder and a relative of Henry Clay, he was strongly influenced by the abolitionist ideas of William Lloyd Garrison. In 1845 he founded the antislavery publication True American in Lexington, Ky., but he was forced by opponents to move it to Cincinnati, Ohio, and then to Louisville, Ky., where it was renamed The Examiner. He helped found the Republican Party in 1854. As U.S. minister to Russia (1861–62, 1863–69), he helped negotiate the Alaska Purchase.

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