established a series of teachers' courses. In this way he encouraged the revival of working-schools for boys, his primary aim being the mechanical development of the hand and of the eye in asso-. ciation with mental training. He conducted a number of training-schools in Saxony, and introduced a course of modeling and drawing in the institution for the blind at Dresden. the Rhine in 1793-94, and attended the Berlin Academy for young officers in 1801-03, when he attracted the attention and won the favor of Scharnhorst. He was adjutant to Prince Augustus in 1806, was captured with him by the French at Prenzlau, and, after being exchanged, served until 1812 as major in the Prussian General Staff, being employed after 1809 in the Ministry of War, under Scharnhorst. In 1810-12 he CLAUSTHAL, klous'tål (Ger., closed valwas also military instructor to the Crown Prince ley, from Lat. clausum, p.p. of cludere, to close of Prussia, and to Prince Frederick of the Nether-Ger. Thal, valley). An important mining lands. At the outbreak of the Russian War in town in the Prussian Province of Hanover, sit1812, he entered the Russian service, and aided uated on a plateau of the Upper Harz, about Diebitsch in concluding the convention of Tau1800 feet above sea-level, and 25 miles northeast roggen. He accompanied Blücher as Russian of Göttingen (Map: Prussia, D 3). Among its staff officer during the campaign of 1813, the his- public buildings the most noteworthy is the tory of which he wrote, at the instance of Gnei- Church of the Holy Ghost, the largest structure senau. He reëntered the service of Prussia in of its kind in the world. The mines of Clausthal 1814, was appointed chief of staff under Thiel- yield silver, lead, copper, iron, and zinc, and are mann in the following year, and remained in that position at Coblenz until 1818, when he among the most valuable and productive in Germany. In 1903 they employed 3270 miners. was made major-general and director of the They are owned and operated by the Prussian 'Allgemeine Kriegsschule.' Finally, he was ap- Government which has established in connection pointed, in 1831, chief of staff to Field-Mar- therewith a mining academy, with an experishal Gneisenau, and served first in Berlin, then mental laboratory, model workshop, and a library on the Polish frontier. His writings are of of over 30,000 volumes; the number of its stugreat value, and have led to a considerable dents in 1905 was 160. The greater portion of the change in the theory of war. They were published male population finds employment in the mines after his death as Hinterlassene Werke über and smelting-works, while the women are occuKrieg und Kriegführung (10 vols., 1832-37), of pied in the knitting-mills. Population, in 1900, which the most noteworthy are: Vom Kriege; 8565; in 1905, 8632. Clausthal was founded by Der Feldzug von 1796 in Italien; Uebersicht des the Dukes of Brunswick, in the Sixteenth Century. Feldzuges von 1813; Der Feldzug von 1815; Ueber das Leben und den Charakter von Scharnhorst. CLAUSIUS, klouʼzê-us, RUDOLF JULIUS EMANUEL (1822-88). A German physicist, born at Köslin. In 1855 he became professor in the Polytechnic Institute of Zurich, in 1867 professor in the University of Würzburg, and in 1869 professor at Bonn. Clausius is one of the founders of the modern science of thermodynamics (q.v.), and in a paper before the Berlin Academy of Sciences (1850) stated the second law of thermodynamics, that "heat cannot of itself pass from a colder to a hotter body." The theory of electrolysis advanced by Clausius has also played a conspicuous part in electricity. He assumed that the ions are not in complete union, but that a part of them are free to unite with other ions. These uncombined ions, accordingly, are brought together under the action of the current at the anode and cathode. Clausius was one of the most celebrated mathematical physicists of the nineteenth century, and his researches and writings in heat, electricity, and molecular physics were of the greatest value. His most important works are: Die mechanische Wärmetheorie (1876); Die Potentialfunktion und das Potential (1859); and Ueber das Wesen der Wärme, verglichen mit Licht und Schall (1857). For a biography of Clausius, consult Riecke, Rudolf Clausius (Göttingen, 1889). CLAUSON-KAAS, klouʼzon-käs', ADOLF VON (1826-). A Danish promoter of manual training. He was born near Altona, Prussia, of Danish parents, and after serving in the Danish cavalry devoted himself entirely to the advancement of education. In 1870 he founded the Danish Clubs for Home Industry. On the occasion of the international expositions of 1873 and 1878, he gave a series of public lectures on manual training in several cities of Germany, Holland, Russia, France, and elsewhere, and also CLAVAʼRIA (Neo-Lat. nom. pl., from Lat. clava, club). A genus of fungi of the division Hymenomycetes, subdivision Clavati. The spores are produced equally on all parts of the surface. The species are numerous, some of them simple and club-shaped, some branched. Clavaria botrytis, a species common in oak and beech woods in Germany, growing on the ground among moss, grass, heath, etc., is gathered when young, and used as food, having a very agreeable sweetish taste. It ceases to be edible when it becomes old. Another German species, Clavaria flava. which grows on sandy ground in fir-woods, is used in the same way. Other species appear to them to contain the saccharine substance called possess similar properties, and Liebig found mannite. Clavaria botrytis is the Keulenpilz, and Clavaria flava the Ziegenbart (goat's-beard) of the Germans. See Colored Plate of EDIBLE FUNGI. CLAVERACK, kláv′-ĕr-ak. A town in Columbia County, N. Y., 30 miles south of Albany, and 3 miles east-southeast of Hudson, its banking point, on the Boston and Albany Railroad. Among the points of interest are a Dutch Reformed church, built in 1767, and an old courthouse, erected in 1784. The chief industries are agriculture and the manufacture of flour and farm implements. Settled as early as 1660, Claverack (named Klauver Rachen, "clover reaches," by the Dutch) was organized as a town in 1778, and was the county-seat from 1786 to 1806. The government is administered by town meetings, held every two years. Population, 1900, 4416; 1905, 4459. CLA VERHOUSE. See GRAHAM, JOHN. CLAVICHORD, klǎv'i-kôrd (Fr. clavicorde, Med. Lat. clavichordium, from Lat. clavis, key + chorda, string). An instrument of the harpsichord family, and an important step in the evo CLAVICHORD. 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 FRANCISCO XAVIER (1731-87). A Mexican hisCLAVIJERO, or CLAVIGERO, klä'vê-Ha'rð, 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, be 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. CLAVIGO, Span. pron. klä-ve'Go. A play by Goethe (1774), based on 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 lane. The route followed by him from his point Henry III. of Castile as ambassador to Tamerof 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 stratified, 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. In 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: (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 |