Page:The New International Encyclopædia 1st ed. v. 04.djvu/500

* CENTRING. 428 CEPHALIZATION. push the crowTi upward, and therefore the prob- lem of dcsigiiiiif; a framed eeiilring involves the resistance of this tendency, as well as the support- ing of the weiglit of the materials. The centrint; of Waterloo Bridge, over the Thames at London, designed by Hcnnie, pre- sents a fine example of the fulfillment of these requirements. The weight is resisted by direct thrust upon beams passing obliquely down- ward from various parts; one of each pair of these oblique beams thrusts outward, and is directly supported by the abutments: the other thrusts inward, toward a support equidistant from the abutments, the yielding of which is prevented by the longitudinal pull of lower and longer oblique beams. In this and other modern structures cast-iron shoes have been successfully used for the tying joints subject to the longi- tudinal pulling strain. The flexible centring, so called from its yielding at the joints, and varying its form with the load put upon it, is now aban- doned. It was chiefiy used by French engineers. That of Perronel for the bridge of Neuilly is a celebrated example. Occasionally, when a very great span is required, and the navigation will permit, piers are built or piles are driven to support the centring, and the design is much simplified thereby. Cupolas like the Pantheon and Saint Peter's in Rome. Saint Paul's in Lon- don, or the flat domes of the Turkish mosques, require very effective centrings. See Bridge- BvlMllNG: TCNXEL. CENTRIP'ETAL FORCE, See Central Forces. CENTROSOME (from Gk. Kcvrpav, kentron, centre + oufia, sOma, body). The two polar centres of the spindle, or the two 'dynamic cen- tres' from which the 'archoplasmic' threads radi- ate and toward which the halves of the split chromatin elements are drawn at the time of cell-division. During the resting stage of the cell (inly one centrosome is present. See Cell; Fmbuyoi.ogy. CENTUM'VIRI (Lat. nom. pi., board of a hundred men. from centum, hundred + j.'i»-, man). In ancient Rome, a body of judges, three from each tribe, in charge of civil cases. L'nder the Empire the number was increased to 180, presided over by the Decemviri Stlilihiifi liidi- candis, and the sessions were held in the Basilica Julia, in the Forum. Here the younger Pliny pleaded, and the Emperor Trajan sometimes lis- tened to the arguments. CENTU'RION (Lat. centurio, from centuria, company of a hundred, from centum, hundred). In the Roman Army, the captain of a centuria or company. There were sixty centurions in each legion, a jvmior and a senior for each of the thirty mnniples; and the senior of the first maniple of the first cohort was the chief centu- rion, or primipilus, of the legion, and often had the real lonniKind of the entire body. CENTURIPE, ehfn'tofi-re'pa. A city in Sicily, 28 miles northwest of Catania, formerly called Ccntorbi (Map: Italy, .1 10). It was destroyed in 123.3 by Emperor Frederick II., and the inhabitants were transplanted to his new- town, Agiista (q.v.), but it wa.s rebuilt in 1548. Population, in 1881 (commune), 9000; in 1901, 11.311. CENTURY PLANT. See AGA^•E. CENTURY WHITE. The nickname of John White I lo'.lO-KU,")) . author of First Century of i^canduluus Muliijimut J'ricsts. CEORL, keorl or chfrl (AS., man, husband, Ger. Kcrl, man, possibly ultinuitely connected with Skt. jura, bridegroom, paramour), (jr Chvrl. In the Anglo-Saxon social order, a com- mon freeman, as distinguished from an eorl (earl), who was a privileged freenuin. As the term curl did not originally inqily a patent of nobility, nor even lordship or dominion, but only superior birth and social position ; so the title ccurl implied no degradation or inferior st;itus, but. on the contrary, marked its possessor off from the lower classes — the tact, or unfree man, and the throir, or slave. The eeorl was capable of owning land, and had a share in the conunon plowland and meadow-land of his comunuiity. The ceorls were the citizens of the murk (q.v.), or hundred (q.v.), composing the vtoot (q.v.), or general assembly of the people, and administer- ing the local justice and government. See Vil- I.EIN.GE, and consult the authorities there re- ferred to; also Freeman. History of the Xorman Conquest of England, Vol. I. (2d ed., Oxford, Eng.. 1870-76). CE'OS. See Zea. CEPH'AE'LIS. See Ipecactanha. CEPH'ALAL'GIA. See Headache. CEPHALAS^PIS (Xeo-Lat., from Gk. ot- <pa-/i, kephalO, head + do-Tr/s, aspis, shield). A genus of primitive armored fossil fishes of the order Osteostraci, found in the brackish and fresh-water deposits of the British and North American. Devonian formations. The body was elongated, triangular in section, and covered throughout with armor. The armor of the head region consists of a single heavy principal plate on the dor.sal surface, which, when viewed from above, has the form of a lun-seshoe or the cara- pace of a king-crab (Limulus). A ventral plate is opposed to the dorsal plate and there are a few small accessory plates. There are no jaws, for the mouth was of the same form as that of the nuKlern lamprey-eel. in which animal it is a sucking organ. Indeed, the lampreys arc believed to be degenerate descendants from early heavily armored types like Cephalaspis and its associates among the Ostraeodermi. The skeleton of Ce- phalaspis must have been wholly cartilaginous, for no traces of it have been preserved. The body was covered by bonj' scale-like rings, it had a single dorsal fin, and the tail-fin was hetero- cereal as in the modern sharks. The best ex- amples of Cephalaspis have been obtained in the Old Red Sandstone of .Scotland and England. The American examples are of less satisfactory preservation and are found in the Ocvouiaii sanil- stones of the [UoviiUH's of Xew Brunswick ami I^Hic- liec. Caiuida. Vnv illu~t ration, see Ostkacookk.mi. CEPHAL'IC INDEX. See Index, Ceimialic, etc. CEPH'ALIZATION (from Gk. «0aXi), kc- phulc, head). The phenomena of progressive concentration and enlargement of the parts of the body belonging to the head; a phenomenon characteristic of segmented animals. Cephaliz;t- tion is onl.v a special case of the law of division of labor. In the earlier metameric animals the head is only slightly diflerent externally from the other segments, and consists of but two or