lution of the pianoforte. Its history previous to the fifteenth century is unknown. The clavi chord was shaped like the square pianoforte, having a keyboard of white and black keys, and strings of brass wire set in vibration by the action of tangents or 'jacks' covered with metal. Its tone, though weak, was delicate, and, unlike the harpsichord, or spinet, in which the strings were plucked or twanged by quills or pieces of hard leather, it responded to the gradations of the player's touch. The clavichord was used in Germany until the beginning of the nineteenth

CLAVICHORD.

century. Bach preferred it to the pianoforte of his day, and wrote an essay for his son, Versuch über die wahre Art Klavier zu spielen, for this instrument. Mozart used the clavichord in composition, and Beethoven preferred it to other keyed instruments; for upon it, he said, "one could best control tone and expressive interpretation." See HARPSICHORD; SPINET.

CLAVICLE (Lat. clavicula, a little key, dim. of clavis, key). or COLLAR-BONE. A long bone, curved somewhat like the italic letter f, and placed at the upper and anterior part of the thorax, in a nearly horizontal position. In connection with the scapula or shoulder-blade, the clavicle forms the shoulder, and is the only bony connection between the upper extremity and the trunk. The inner extremity of the clavicle articulates with the sternum (breast-bone) and the cartilage of the first rib, while the outer extremity articulates with the scapula. The range of motion in the clavicle is extensive especially in a vertical direction-and the various movements of the arm are in this way readily accommodated. In the female the clavicle is smoother, slender, and presents a less marked curve. The length, also, is slightly less, and the position more nearly horizontal. Manual labor, which brings the shoulder into constant exercise, renders the clavicle thicker and tougher, and therefore in right-handed people the right clavicle shows greater development.

Since the clavicle favors the lateral movements of the upper extremities, we do not find it in animals whose fore limbs are used only for progression; but it is present in almost all animals whose anterior extremities are clawed and used for prehension.

The clavicle is frequently fractured by direct violence, and also by indirect force, as in falling upon the hand. Dislocations are of less frequent

occurrence.

Ossification of the clavicle begins very early even as soon as the thirteenth day, according to Béclard-and at birth this process is almost complete. Consult: Gray, Anatomy, edited by Pick

(London, 1901); Holden, Human Osteology (New York, 1902).

CLAVIER, klå-ver' (from Lat. clavis, key). The German name for the pianoforte, and the prototype of the clavichord (q.v.). In French, clavier' designates the keyboard of an organ or pianoforte. For the practice clavier, see PIANOFORTE.

FRANCISCO XAVIER (1731-87). A Mexican hisCLAVIJERO, or CLAVIGERO, klä'vê-Ha'ro, torian, born in Vera Cruz. the Order of the Jesuits, and became a teacher He early entered of rhetoric and philosophy. He lived among the Indians in various parts of Mexico as a missionary for many years, and made himself fully acquainted with the languages, traditions, and antiquities of the aboriginal tribes. On the expulsion of the Mexican Jesuits by Spain, in 1767, he sailed for Italy, and with others of his Order settled in Bologna, where he founded an academy. He wrote, in Spanish, a work on early Mexican history; but, in order to publish it, he was obliged to translate it into Italian. The work finally appeared as Storia antica del Messico (1780); it is a comprehensive and valuable history of the Aztec Period. An English translation was made by Cullen (London, 1787). Clavijero also wrote Storia della California (1789), and works on physics and philosophy.

Goethe (1774), based on CLAVIGO, Span. pron. klä-ve'Go. A play by an episode in the and journalist. life of José Clavijo y Fajardo, a Spanish official

CLAVIJO, klä-vě нo, DON. A character in Don Quixote, delivered by Don Quixote from the form of a crocodile, into which he had been changed by enchantment.

CLAVIJO, RUY GONZALEZ DE (?-1412). A Spanish traveler in the Orient. He was born in Madrid, and in 1398 and 1403 was sent by Henry III. of Castile as ambassador to Tamerlane. The route followed by him from his point of departure, Cadiz, took him to Trebizond, Armenia, Persia, and Khorasan. He arrived at Samarkand in 1404, and was well received at the Court of Tamerlane. After his death, his suite returned alone, after an absence of three years. The journal' of Clavijo was published under the title Historia del gran Tamerlán é itinerario

narración del viaje, etc. (1582; reprinted in 1782). It is valuable, not only because of its high literary merit, but also for its historical importance.

CLAVILEÑO, Sp. pron. klä'vê-la'nyo, EL ALIGERO. The wooden horse, said to have been constructed by Merlin, which was managed by a wooden pin in its forehead; whence its name, 'the winged pin-timber.'

CLAY (AS. clæg, Ger. Klei; ultimately connected with Lat. glus, gluten, glue, Gk. yλobs, gloios, gum, OCh. Slav. glēnu, slime). A term applied to earthy material or soil which shows plasticity when wet, thus permitting it to be molded into any desired form, which it retains when dry. Its distinguishing character is a physical one; for clay varies widely in other respects, being made up of fine mineral fragments, the most prominent of which may be the mineral kaolinite, a hydrated silicate of alumina. Clay is formed primarily by the decomposition of feldspathic rock in situ, and such a

clay is said to be residual in its nature. The material, however, is often washed down into the lakes or ocean by the surface-waters, and there spread out over the bottom as an aluminous sediment; such a clay deposit being known as a sedimentary one, which is not only strati fied, but may also be more extensive than a residual. Sedimentary clay sometimes becomes consolidated by the pressure of other sediments which have been deposited on top of it, and it is then termed shale. These shales, on grinding and mixing with water, develop the same plasticity as does soft clay.

The chief chemical constituents of clay are silica and alumina; but, in addition to these, variable quantities of iron oxide, lime, magnesia, alkalies, water, and even rarer substances are often present. These ingredients affect the physical properties of the clay; such as its color when burned, air and fire shrinkage, refractoriness, plasticity, and thus indirectly its uses. The lime, magnesia, iron oxide, and alkalies exert a fluxing action in burning, and the greater their quantity the lower the fusing-point of the clay. Silica decreases the air and fire shrinkage of a clay, while alumina and water have the reverse effect. The property of plasticity, together with that of hardening under fire, makes clay an article of great value in the plastic arts. Those clays which are low in plasticity are said to be 'lean,' while the highly plastic varieties are 'fat.' Clay does not fuse suddenly, but softens gradually under the influence of heat. very fusible clays this sintering may begin at 1500° or 1700° F., while in very refractory kinds it does not take place until a temperature of 3000° F. or more is reached. The red color of a burned clay is due to considerable iron oxide, while buff is produced by a small quantity of iron, or by an excess of lime. The following table gives the composition of several grades of clay:

In

5

6

(1) Crude kaolin, Webster, N. C.; (2) Washed kaolin, Webster, N. C.; (3) Fire-clay, Wymp's Gap, Pa.; (4) Paving,

brick shale, Kansas City, Mo.; (5) Brick-clay, Indianola,

Iowa; (6) Calcareous slip clay, Albany, N. Y.

Clay is used in the manufacture of common, pressed, and paving brick; terra-cotta, fireproofing, terra-cotta lumber; roofing, floor, and glazed tile; firebrick, retorts, crucibles, muffles, and other refractory goods; all grades of pottery, stoves, sewer-pipe, door-knobs, electrical insulators, turbine-wheels, closets, and bathtubs and washtubs; filters, mineral paint, food-adulterants, Portland cement, paper fillers, emerywheels (as a cement therein), ultramarine, modeling, soap, etc.

Clay is widely distributed geographically, and also geologically--i.e. in the rock-formations of different ages. In the United States deposits are found at a great number of localities. The Cretaceous clays of New Jersey are much used in the manufacture of refractory goods and white

ware, while the Carboniferous clays of Pennsylvania and Ohio are also extensively employed for making firebrick. Kaolin is quarried at several points in North Carolina, Georgia, Maryland, and Wisconsin; much white ball-clay is found in Florida, and stoneware-clay in Illinois and Missouri. Clays suitable for brick, terracotta, and sewer-pipe occur at many points all over the United States. In the Central States, clays suitable for the manufacture of vitrified paving-brick are actively worked. With all this supply, however, much ball-clay and kaolin is imported, the material coming chiefly from England. Over $125,000,000 worth of clay products are produced annually in the United States alone.

The different varieties of clay are as follows: KAOLIN (q.v.) or CHINA-CLAY. A very white burning clay, used in the manufacture of porcelain and white earthenware. It is of residual origin, and often occurs in the form of veins.

FIRE-CLAYS (q.v.). Clays containing a low percentage of fluxes, and hence capable of resisting high temperatures. They are used in the manufacture of all classes of refractory goods, and sometimes also for making pressed brick and terra-cotta.

FLINT-CLAY. A dense, hard, non-plastic fireclay, often found in the Carboniferous formations.

PIPE-CLAY. A term applied to many smooth, highly plastic clays.

BRICK-CLAY. A term including almost any impure clay which can be molded into bricks. TERRA-COTTA CLAY. A grade of clay used for making terra-cotta (q.v.). It includes many varieties.

SLIP-CLAY. An easily fusible clay, which melts to a translucent glass, and is used for glazing the cheaper grades of pottery.

POTTERY-CLAY. A term applied to any clay used in the manufacture of pottery.

SAGGAR - CLAY. A grade of fire clay used for making saggars, or vessels in which fine pottery is placed during baking in the kiln.

ALUM-CLAY. A clay containing a large amount of alum.

MARLY CLAY. A clay containing from 20 to 30 per cent. of lime carbonate.

GUMBO CLAY.

A very plastic, sticky clay, found in many localities in the Central States, and often used in the manufacture of railroad ballast.

BALL-CLAY. A plastic, white burning clay, used as a bonding ingredient in white-ware and porcelain bodies.

CLAY MINING AND WORKING. The preparation of clay for use in the plastic arts is a simple process, owing to the accessibility of clay-banks and strata, and the ease with which the material can be separated from the other substances with which it is commonly found. After preliminary exploration and testing, the first thing to be done is to remove in cars, wagons, or carts the top layer of dirt. The digging out of the clay itself is usually done in successive pits, the dirt from the pit under excavation being thrown into the pit that has just been dug. In digging clay, a gouge-spade is used, which differs from the ordinary spade in having the blade cylindrical and the upper edge broader. A platform of boards is placed beside the pit, on which the clay is thrown and sorted.

Two

workmen handle each spadeful of clay; the first merely loosens it up, while the second cuts out any nodules of pyrite or other foreign matter, and then throws the clay onto the platform, where it is sorted for ware, brick, or whatever product it is best suited. When clay is very hard, it is first loosened with a pick. Dynamite is sometimes employed to break up a bank into loose pieces. Occasionally, mining underground is necessary to reach a desired quality of clay; and this method will be more and more common as the best grades of superficial clays are exhausted. The clay having been mined and sorted, it is transported to the factory for further manipulation.

Clay-working or tempering of some sort is generally required before clay can be used, and particularly before it can be molded into brick, pottery, sewer-pipe, or tiles. Reduction to a plastic state may be effected by wet or dry grinding, screening, pugging, washing, or by the more natural process of weathering; or, a combination of two or more of these methods may be employed. The screening and washing may be so arranged as to remove foreign material. It must be understood that the term 'clay-working,' as here used, is limited to the preparation of the raw material for molding or forming, the other processes being treated separately, under the various clay products, as will be the matter of drying; while burning, for the most part, will be discussed under KILNS.

Weathering is a self-explanatory term. The time involved may range from months to years, but is more often the shorter period. With improvements in machinery and methods, less dependence is placed on this process than formerly.

Soaking, like weathering, is a natural process, but it is now used only under primitive conditions, and where the clay is molded in a soft form, without other working. The clay is simply shoveled into pits, say 4 X 6 feet in extent, and soaked in water over night.

Ring-pits are 25 to 30 feet in diameter, 3 feet deep, lined with brick or boards. An iron wheel is passed over or through the clay, back and forth, mixing in the sand, in case any is used. Clay for some 30,000 bricks may be tempered in six hours.

DRY-PAN CLAY-GRINDING MACHINE.

Grinding is accomplished by passing the clay between rolls, or in dry pans, the former process

being particularly applicable to shales. The pans are 7 to 9 feet in diameter, with either perforated floors or sides, through which the material falls as soon as it has reached the desired fineness. The pan revolves horizontally and by means of friction motion is imparted to two iron wheels, mounted in the pan, 6 to 14 inches wide, weighing 2000 to 6500 pounds each. A pan with one-eighth-inch holes has an average capacity of 100 tons of clay per day of ten hours.

Screening is sometimes employed for clay which has passed the dry pan. Screens may be inclined sieves, either fixed or shaking, and ro tary cylindrical or octagonal in form. They de mand much attention to prevent clogging, and require heavy repairs, but nevertheless are cheap and simple in operation.

Wet pans are much like dry pans, only their bottoms are not perforated, and scrapers are placed in front of the wheels, to throw up the clay. They may be discharged through a trapdoor or by means of an automatic shovel. One of their chief advantages is rapidity, only two or three minutes being required to temper a charge for brick and four or five minutes for sewer-pipe.

Pug-mills appear to be used more than other classes of tempering machines. They are either vertical or horizontal, but in either case they have a central revolving shaft, fitted with radial knives extending nearly to the surrounding cyl

COMBINED MIXING AND PUGGING MACHINE.

inder in which the clay is placed, or else fitted with a worm screw. Both knives and screw force the clay forward, as well as work it thoroughly, and by changing the angle of the adjustable knives the speed of the passing clay may be regulated. Water is admitted as desired and needed. When the clay is deficient in redness after burning, hematite may be added to the pug with clay. Pug-mills are compact, and require less power than ring-pits.

Washing is effected by a variety of processes, ranging from simple to complex. All of them involve a reduction of the clay in water to a semi-fluid state, or even to a state of suspension, which may be brought about by revolving paddles or blades, mounted on a shaft in a cylinder or trough, or by any thorough stirring. The heavier, coarser impurities may be deposited in a vat by sedimentation. The water, with the remaining clay, may be removed by siphoning or carefully poured off, and the clay allowed to settle. This process is sometimes called ebullition, particularly where it is repeated many times to recover fine-grained material. The process of sedimentation may be altogether too slow, especially where large quantities of clay are to be treated, and in such a. case the clay and water, after being reduced, as described, to what is known as slip, may be passed through shaking-screens of wirecloth, having forty meshes to

the inch. It is then sent to an agitator, or large tank fitted with revolving paddles, to prevent sedimentation, from which tank the screened slip is forced by means of compressed air into a series of canvas-lined compartments, known as a press, where the water is expelled by the force of the air. The press being loosened, the clay is removed in sheets or cakes one to two inches thick, weighing 30 to 40 pounds each, after which it is ready for the pug-mill. Washing is used in the preparation of some sorts of clay for making into pottery.

BIBLIOGRAPHY. Bock, Die Ziegelindustrie (Leipzig, 1897); Dummler, Handbuch der Ziegel-fabrikation (Halle, 1897); Ries, "The Clays of New York: Their Properties and Uses," in New York State Museum Bulletin No. 35 (Albany, 1900-contains much general information on the properties of clay and the methods of manufacture); Young, The Ceramic Arts (New York, 1878); Prime, Pottery and Porcelain of All Times and Nations (New York, 1878); Barber, Pottery and Porcelain of the United States (New York, 1900); Ries, Clays of the Northern States East of the Mississippi River (Washington, 1903); id., Clays and Clay Industry of New Jer sey, with others (Trenton, 1904); Blatchley, "Clays of the Coal-Bearing Counties of Indiana," in Twentieth Annual Report of the Geological Survey of Indiana (Indianapolis, 1896); Branner, "Bibliography of Clays and the Ceramic Arts," in United States Geological Survey Bulletin No. 143 (Washington, 1896); Buckley, "The Clays of Wisconsin," in Wisconsin Geological Survey Bulletins, vol. ii., part i. (Madison, 1901); Cook, "The Clays of New Jersey," in New Jersey Geological Survey Report for 1878 (Trenton, 1878); Orton, "Clays and Clay-Working Industries of Ohio," in Ohio Geological Survey, vol. vi., part i. (Columbus, Ohio, 1893); Ries, "The Clays of Alabama," in Alabama Geological Survey Bulletin No. 6 (Jacksonville, Fla., 1900); Ries, "The Clays and Clay Industries of North Carolina," in the North Carolina Geological Survey Bulletin No. 13 (Raleigh, N. C., 1897); Ries, "The Clays and Shales of Michigan," in Michigan Geological Survey, vol. viii. (Lansing, Mich., 1901); Wheeler, "The Clays of Missouri," in Missouri Geological Survey, vol. xi. (Jefferson City, Mo., 1896). See ALUMINA; SHALE: PIPE-CLAY; KAOLIN; FIRE-CLAY; LOAM; SOIL; BRICK.

For the character, distribution, and methods of manufacture in the United States, consult: The Mineral Industry (New York, 1892 et seq.); also, Davis, Practical Treatise on the Manufac ture of Bricks, Tiles, and Terra-Cotta (Philadelphia, 1895).

CLAY, CASSIUS MARCELLUS (1810-1903). An American abolitionist and politician, born in Madison County, Ky. He graduated at Yale in 1832, returned to Kentucky to practice law, and was elected to the State Legislature in 1835, in 1837, and in 1840, but in 1841 failed of reëlection on account of his strong anti-slavery opinions. In 1844 he made speeches in the Northern States in advocacy of the election of Henry Clay to the Presidency, and in the following year op posed the annexation of Texas, and established at Lexington, Ky., The True American, a vigorous anti-slavery paper, which, however, was suppressed by a mob, but was revived by Mr. Clay, and was published thereafter in Cincinnati. He

volunteered for service in the Mexican War in 1846, and was taken prisoner. In 1850 he left the Whig Party, and was the Anti-Slavery candidate for Governor. In 1860 he supported Lincoln, and in 1861 was appointed Minister to Russia, but returned to the United States in 1862, and was made major-general of volunteers. In 1863, however, he resigned, and was again appointed Minister to Russia, where he remained until 1869. He supported Greeley in 1872 and Tilden in 1876, but went over to the Republican Party to vote for Blaine in 1884. In the campaign of 1896 he was in the gold-standard wing of the Democratic Party. Consult his Life, Memoirs, Writings, and Speeches (Cincinnati, 1886).

CLAY, CLEMENT CLAIBORNE (1819-82). An American politician, born at Huntsville, Ala. He graduated at the University of Alabama in 1835, and was admitted to the bar in 1840. From 1842 to 1845 he was a member of the State Legislature, from 1846 to 1848 was judge of the Madison County Court, and in 1853 was elected to the United States Senate. Upon the secession of his State he withdrew from the Senate, and was forthwith elected to the Confederate Congress. Having taken refuge in Canada at the overthrow of the Confederacy, he later gave himself up, and in 1865-66 was imprisoned at Fortress Monroe with Jefferson Davis.

CLAY, FREDERICK (1840-89). An English musician. He was born in Paris, received his education under Molique in Paris and Hauptand wrote several operas and operettas, which mann in Leipzig; returned to England in 1860, were successful. His works include: Constance (1865); Happy Arcadia (1872); Don Quixote (1875); Princess Toto (1875); The Golden Ring (1883); and the Black Crook, with Jacobi (1873); also incidental music to Twelfth Night, songs, part-songs, and cantatas.

CLAY, GREEN (1757-1826). An American soldier. He was born in Powhatan County, Va.; became a pioneer settler in Kentucky, then a part of Virginia, about 1776; represented the district for some time in the Virginia Legislature, and was a member of the State Constitutional Convention of 1799. In 1813 he led the force of 3000 which relieved General Harrison, then besieged by the British and Indians at Fort Meigs, and afterwards defended that fort against General Proctor and Tecumseh. He was the father of Cassius Marcellus Clay, and a cousin of Henry Clay. See FORT MEIGS.

CLAY, HENRY (1777-1852). An American statesman, known, from his skill in devising compromises, as the 'Great Pacificator.' He was born April 12, 1777, in a neighborhood called 'The Slashes,' in Hanover County, Va. His father, a Baptist clergyman in humble circumstances, died when Henry was only four years old; and his mother, who seems to have been a woman of forcible character, was left ill provided for. Mrs. Clay married again in a few years, and her second husband secured for Henry the position of clerk in a retail shop in Richmond. This careful stepfather, however, noting the brightness and promise of the lad, used his influence in obtaining for him an appointment in the office of the clerk of the High Court of Chancery, where he remained for four years. Here he attracted the notice of the Chancellor, George Wythe, and

was employed by him to copy documents. The intimate association with Chancellor Wythe was an important influence on Clay's life and development; for he had received almost no schooling, and he never studied regularly, save for one year in the office of Robert Brooke, then Attorney-General of Virginia. Clay was admitted to the bar at twenty, but he soon left Richmond, and sought the fuller opportunities of the West, at Lexing ton, Ky. Here his attractive personality and his skill as a speaker won him friends, and made him a leading jury-lawyer. It was not long before he turned his attention to politics, and when, in 1799, the revision of the Kentucky Constitution was undertaken, Clay was found playing an active and honorable part with the minority, and risking his personal prestige by his advocacy of the gradual abolition of slavery. This stand might have cost him dear, had he not soon afterwards been able by his eloquence to aid his State heartily in opposing the Alien and Sedition Laws. He married in 1799, rose steadily in his profession, and was elected to the State Legislature in 1803. In 1806, having been appointed to represent Kentucky for an unexpired term in the United States Senate, he took from the first a conspicuous part in the publie business; bringing in a number of resolutions and sitting on several committees. His first speech-one on the bill for a bridge across the Potomac-indicates his future course as one

of the most earnest advocates of the policy of internal improvements. Scarcely had he returned to Kentucky when he was reelected to the State Legislature and made Speaker. It was at this time that, sharing the rapidly growing hostility toward England, and desiring to foster domestic manufactures, he introduced the resolution that all members of the Legislature should wear no clothing made in foreign countries a proposal that Humphrey Marshall, a Federalist, stigmatized as the utterance of a demagogue. Angry words were passed, a challenge followed, and in the duel that was fought both parties were slight ly wounded. In the winter of 1809-10 Clay was again sent to fill a vacancy in the Senate, where he continued to be the champion of the protection of home manufactures. When the question of chartering the United States Bank came up, Clay opposed the measure as corrupt and unconstitutional; and his remarks on this occasion were treasured up to be used with great effect against him when, in 1816, a revival of the matter made manifest an alteration in his views.

Entering the National House of Representatives in 1811, Clay was chosen Speaker as soon as he appeared, and as leader of the vigorous democracy sprung up since the Revolution, he practically forced the war with England, speaking with rash confidence of the ease with which Canada could be overrun by his fellow Kentuckians. He supported the war with all his eloquence, in and out of Congress, and was in consequence known as the 'War Hawk;' he advocated an increase of the army, and aroused much enthusiasm for his measures. When the war seemed nearly a failure, he was one of the commissioners to arrange terms, resigning the Speakership in January, 1814. In spite of the disappointment the war had brought to his hopes, he contributed much to the success of the commissioners, who were far superior to the British representatives opposed to them, and who secured the best

possible terms in the Treaty of Ghent. He resist ed especially the British claim to the right of navigating the Mississippi. On his return in 1815, Clay, as the leading war statesman, was royally welcomed. During his absence he had been reelected to the House of Representatives, and, declining the offer of the mission to Russia, he took his seat and was chosen Speaker-an office which the later tender of a Cabinet place did not induce him to resign. The tariff of 1816, which was moderately protective, was urged by Clay, on the ground that certain industries must be built up for the nation's safety during war. This same year he advocated the rechartering of the National Bank to renew specie payments and to prevent further distress, and with Calhoun he helped to pass the bill for internal improvements vetoed by Madison. The Fifteenth Congress met December 1, 1817, and Clay was again elected Speaker. In this session he continued to assert the power of Congress to construct internal improvements, and he pleaded earnestly for the recognition of the South American republics, a cause always dear to his warm heart.

Clay was again chosen Speaker on the meeting of the Sixteenth Congress and continued to be its leading member, frequently criticising Monroe's administration in hard terms. This was the period of the great contest over the admission of Missouri.

Clay, though not the author of the Missouri Compromise of 1820, did bring about the compromise of the next year, by which it was agreed that Missouri should be admitted (without restriction as to slavery) on her promise not to prevent citizens of other States from settling within her borders. Declining reëlection to the following Congress, he did not appear in active politics again until 1823, when he reoccupied the Speaker's chair. In the election of 1824 he was a candidate for the Presidency, together with Crawford, Jackson, and Adams.

The Electoral College failing to elect, the choice between the three highest candidates fell to the House, where Clay, who had come fourth and was thus not eligible for election, cast his strength for Adams. Soon after the latter's inauguration, Clay was appointed Secretary of State-a fact which gave point to the cry of 'Bargain and corruption,' which, though baseless, and again and again refuted, never ceased to injure him in his political career. His relations with Adams were denounced by John Randolph as the "combination of the Puritan with the blackleg," language which provoked a challenge from Clay; but neither party was wounded in the duel that ensued, Randolph refusing to fire at his adversary the second time. The Secretaryship of State, formerly regarded as the stepping-stone to the Presidency, proved an obstacle to Clay, and though he made an excellent officer, he regretted his long absence from Congress, where he could always lead. A strong opponent of General Jackson as a candidate for the Presidency, he retired with Mr. Adams after the latter's defeat in 1829. Two years later he was elected to the Senate. Here, in the difficult rôle of Senator and Presidential candidate, he was prominent in his advocacy of the protective system, which he dubbed unreasonably, but successfully, the 'American system.' Unanimously nominated by the Whigs, Clay was overwhelmingly defeated by Jackson