ORIHUELA, a town and episcopal see of eastern Spain, in the province of Alicante; 13 m. N.E. of Murcia and about 15 m. from the Mediterranean Sea, on the Murcia-Elrhe railway. Pop. (1900) 28,530. Orihuela is situated in a beautiful and exceedingly fertile hucrta, or tract of highly cultivated land, at the foot of a hmestone bridge, and on both sides of the river Segura, which divides the city into two parts, Roig and San Augusto, and is spanned by two bridges. There are remains of a Moorish fort on the hill commanding the town; and the north gateway—the Puerta del Colegio—is a fine lofty arch, surmounted by an emblematic statue and the city arms. The most prominent buildings are the episcopal palace (1733), with a frontage of 600 ft.; the town house (1843), containing important archives; and the cathedral, a small Gothic structure built on the site of a former mosque in the 14th century, and enlarged and tastelessly restored in 1829. The university of Orihuela, founded in 1568 by the archbishop of Valencia, was closed in 1835, part of the revenue being applied to the support of a college affiliated to the university of Valencia. Besides numerous primary schools there are a theological seminary and a normal school. The trade in fruit, cereals, oil and wine is considerable. There are also tanneries, dye-works and manufactures of silk, linen and woollen fabrics, leather and starch.
Orihuela was captured by the Moors in 713, and retaken by James I. of Aragon, for his father-in-law Alphonso of Castile, in 1265. It was sacked during the disturbances at the beginning of the reign of Charles V. (1530), and again in the War of Succession (1706). Local annals specially mention the plague of 1648, the flood of 1651 and the earthquake of 1829.
ORILLIA, a town and port of entry of Simcoe county, Ontario, Canada, situated 84 m. N. of Toronto, on Lake Couchiching and on the Grand Trunk railway. Pop. (1901) 4907. It is a favourite summer resort, and has steamboat communication with other ports on Lakes Simcoe and Couchiching. It contains an asylum maintained by the provincial government; also saw and grist mills and iron foundries.
ORINOCO, a river in the north of South America, falling north-east into the Atlantic between 60° 20′ and 62° 30′ W. It is approximately 1500 m. long, but it is several hundred miles longer if measured by its Guaviare branch. Lying south and east of the main stream is a vast, densely forested region called Venezuelan Guiana, diversified by ranges of low mountains, irregular broken ridges and granitic masses, which define the courses of many une.xplored tributaries of the Orinoco.
In 1498, Columbus, when exploring the Gulf of Paria, which receives a large part of the outflow of the Orinoco, noted the freshness of its waters, but made no examination of their origin. The caravels of Ojeda which, in 1499, followed almost the same track as that of Columbus, probably passed in sight of one or more of the mouths of the Orinoco. The first to explore any portion of the mighty river was the reckless and daring adventurer Ordaz. In his expedition (1531–1532) he entered its principal outlet, the Boca de Navios, and, at the cost of many lives, ascended to the junction of the Meta with the parent stream. From Ordaz up to recent times the Orinoco has been the scene of many voyages of discovery, including those in quest of El Dorado, and seme scientific surveys have been made, especially among its upper waters, by Jose Solano and Diaz de la Fuente of the Spanish boundary line commission of Yturriaga and Solano (1757–1763), Humboldt (1800) and Michelena y Rojas (1855–1857). The last ascended to the Mawaca, a point about 170 m. above the northern entrance to the Casiquiare canal, and then a few miles up the Mawaca. A little knowledge about its sources above these points was given by the savages to de la Fuente in 1759 and to Mendoza in 1764, and we are also indebted to Humboldt for some vague data.
At the date of the discovery, the Orinoco, like the Amazon, bore different names, according to those of the tribes occupying its margins. The conquistador Ordaz found that, at its mouth, it was called the Uriaparia, this being the name of the cacique of the tribe there. The Caribs, holding a certain section of the river, named it the Ibirinoco, corrupted by the Spaniards into Orinoco. It was known to other tribes as the Barraguan and to others as the Maraguaca. The Cabres called it the I'aragua, because it flooded such a vast area of country.
The principal affluent of the Orinoco from the Guiana district is the Ventuari, thu head waters of which are also unknown. It is an important stream, which, running south-west, joins the Orinoco about 90 m. aljove its Guaviare branch. Two other large triljularies of the Orinoco flow north from the interior of this mysterious Guiana region, the Caura and the Caroni. The former has recently been explored by Andre, who found it greatly obstructed by falls and rapids; the latter is about 800 m. long, 400 of which are more or less navigable.
South of the Guaviare, as far as the divortium aquarum, between it and the Rio Negro branch of the Amazon, the country is dry and only partially swept by moisture-laden winds, so that few streams of moment are found in its southern drainage area; but north of it, as far as 6° 30′ N., the north-east trade winds, which have escaped condensation in the hot lower valley of the Orinoco, beat against the cold eastern slopes of the lofty Colombian Andes, and ceaselessly pour down such vast volumes of water that the almost countless streams which flow across the plains of Colombia and western Venezuela are taxed beyond their capacity to carry it to the Orinoco, and for several months of the year they flood tens of thousands of square miles of the districts they traverse. Among these the Apure, Arauca, Meta and Guaviare hold the first rank.
The Apure is formed by two great rivers, the Uribante and Sarare. The former, which rises in the Sierra de Merida, which overlooks the Lake of Maracaibo, has 16 large affluents; the latter has its sources near the Colombian city of Pamplona, and they are only separated from the basin of the river Magdalena by the “Oriental” Andean range. From the Uribante-Sarare junction to the Orinoco the length of the Apure is 645 m., of which Codazzi makes the doubtful claim that 564 are navigable, for there are some troublesome rapids 114 m. above its mouth, where the Apure is 3 m. wide. The numerous affluents which enter it from the north water the beautiful eastern and southern slopes of the Merida, Caraboso and Caracas mountain ranges. A few of them are navigable for a short distance; among these the most important is the many-armed Portugueza, on the main route south from the Caribbean coast to the llanos. A few large streams enter the lower Apure from the south, but they are frequently entangled in lateral canals, due to the slight elevation of the plains above sea-level, the waters of the Apure, especially during flood tirne, having opened a great number of caños before reaching the Orinoco.
The “Oriental” Andes of Colombia give birth to another great affluent of the Orinoco, the Arauca, which soon reaches the plain and parallels the Apure on the south. Perez says that the Sarare branch of the Apure has formed a gigantic dam across its own course by prodigious quantities of trees, brush, vines and roots, and thus, impounding its own waters, has cut a new channel to the southward across the lowlands and joined the Arauca, from which the Sarare may be reached in small craft and ascended to the vicinity of Pamplona. The Arauca is navigable for large boats and barges up to the Andes, and by sail to its middle course. In floods, unable to carry the additional water contributed by the Sarare, it overflows its banks, and by several caños gives its surplus to the Capanaparo, which, about 18 m. farther south, joins the Orinoco.
The Meta is known as such from the union of two Andean streams, the Negro and Humadea, which rise near Bogota. At their junction, 700 ft. above sea-level, it is 1000 ft. wide and 7 ft. deep in the dry season, but in flood the Meta rises 30 ft. It is navigable up to the old “Apostadero,” about 150 m. above its mouth, but launches may ascend it, in the wet season, about 500 m., to the junction of the Negro with the Humadea. In the dry season, however, it is obstructed by reefs, sandbanks, shallows, snags, trees and floating timber from the “Apostadero” up, so that even canoes find its ascent difficult, while savage hordes along its banks add to the dangers to be encountered.
The Guaviare is the next great western tributary of the Orinoco. Eugenio Alvarado, a Spanish commissioner for the boundary delimitation of Colombia with Brazil in 1759, informed the viceroy at Bogota that the rivers Arivari and Guayabero rise between Neiva and Popayan, and unite to take the composite name of Guaviare. In those times they called it Guaibari, or Guayuare. The Guaviare is about 500 m. long, of which 300 are called navigable, although not free from obstructions. Its upper portion has many rapids and falls. The banks are forested throughout, and the river is infested by numerous alligators, so ferocious that they attack canoes. Two-thirds of the way up, it receives its Ariari tributar> from the north-west, which is navigable for large boats. Near its mouth the Guaviare is joined by its great south-western affluent, the Ynirida. Above its rapid of Mariapiri, 180 m. up. this stream runs swiftly through a rough country, but for a long distance is a succession of lakes and shallow, overflowed areas. Its head-waters do not reach the Andes.
Between the Guaviare and the Meta the Orinoco is obstructed by the famous Maipures cataract, where, in several channels, it breaks through a granite spur of the Guiana highlands for a length of about
