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 out the greater part of its course; it drains a region that is famous for the production of wheat; and much water power has been developed on its tributaries. The United States government has improved its channel from the international boundary to Breckenridge, Minnesota, a distance of 395.5 m., and occasionally the water reaches a height which permits small steamboats to ascend its S.W. branch to Lake Traverse and from there to descend the Minnesota river to the Mississippi.  RED RIVER SETTLEMENT, a Scottish colony founded in 1811 near the present city of Winnipeg by a philanthropic Scottish nobleman, Lord Selkirk, who at that time controlled the Hudson's Bay Company. Quarrels soon arose with the French and half-breed employés of the North-West Fur Company, and were fostered by its officials. On June 19, 1816, in a fight between the rivals, Governor Semple of the Hudson's Bay Company and twenty of his twenty-seven attendants were killed, an affair known as the Battle of Seven Oaks. New settlers were sent by Selkirk, and founded the village of Kildonan, now part of Winnipeg. In 1821 the rival companies united, and in 1836 repurchased from Selkirk's heirs all rights to the territory. In 1821 and in 1835 two forts, known as Lower and Upper Fort Garry, were built to command the junction of the Red and Assiniboine rivers, and around them grew up a mixed population of Scots, French and Indians. The purchase in 1869 of the territorial rights of the Company by the Dominion of Canada led to a rebellion, and the setting up of a provisional government under Louis Riel, which was dispersed by a force of British regulars under Colonel (later Lord) Wolseley.

See (History); also George Bryce, Remarkable History of the Hudson's Bay Company (1900).

 REDRUTH, a market town in the Camborne parliamentary division of Cornwall, England, 17 m. E.N.E. of Penzance, on the Great Western railway. Pop. of urban district (1901) 10,451. It lies high, on the northward slope of the central elevation of the county, with bare rocky moors to the south. It is the chief mining town in Cornwall, and the bulk of the population is engaged in the tin mines or at the numerous tin-streaming works. The parish church of St Uny, of which only the tower is ancient (Perpendicular), stands outside the town to the west, at the foot of a rugged hill named Carn Brea. On the summit of this hill, besides a monument (1836) to Lord de Dunstanville and a small ancient castle, various prehistoric remains are traceable. A museum attached to the science and art schools and a miners' hospital are notable institutions in Redruth. A large quantity of the tin is sold by public auction at the mining exchange, the sales being known as tin-ticketing. There are manufactures of safety fuses, breweries, iron foundries and railway works. Tramways serve the neighbouring mines and the small port of Portreath on the north coast.   RED SEA, a narrow strip of water extending S.S.E. from Suez to the Strait of Bab el-Mandeb in a nearly straight line, and separating the coasts of Arabia from those of Egypt, Nubia and Abyssinia. Its total length is about 1200 m., and its breadth varies from about 250 m. in the southern half to 130 m. in 27° 45′ N., where it divides into two parts, the Gulf of Suez and the Gulf of Akaba, separated from each other by the peninsula of Sinai.

The Gulf of Suez is shallow, and slopes regularly down to the northern extremity of the Red Sea basin, which has a

maximum depth of 640 fathoms, and then over a shoal of 60 fathoms goes down to 1200 fathoms in 22° 7′ N. The Gulf of Akaba is separated from the Red Sea by a submarine bank only 70 fathoms from the surface, and in 28° 39′ N. and 34° 43′ E. it attains the depth of 700 fathoms. South of the 1200-fathom depression a ridge rises to 500 fathoms in the latitude of Jidda, and south of this again a similar depression goes down to 1190 fathoms. Throughout this northern part, i.e. to the banks of Suakin and Farsan in 20° N, the 100-fathom line keeps to a belt of coral reef close inshore, but in lower latitudes the shallow coral region, 300 m. long and 70 to 80 m. across, extends farther and farther seaward, until in the latitude of Hodeda the deep channel (marked by the 100-fathom line) is

only 20 m. broad, all the rest of the area being dangerous to navigation, even for small vessels. In the middle of the gradually narrowing channel three depressions are known to exist; soundings in two of these are: 1110 fathoms in 20° N. and 890 fathoms in 16° N., a little to the north of Massawa. To the north-west of the volcanic island of Zebayir the depth is less than 500 fathoms; the bottom of the channel rises to the 100-fathom line at Hanish Island (also volcanic), then shoals to 45 fathoms, and sinks again in about the latitude of Mokha in a narrow channel which curves westward round the island of Perim (depth 170 fathoms), to lose itself in the Indian Ocean. This western channel is 16 m. wide in the Strait of Bab el-Mandeb; the eastern channel of the strait is 2 m. broad and 16 fathoms deep.

Murray estimates the total area at 158,750 sq. m., and its volume at 67,700 cub. m., giving a mean depth of 375 fathoms.

Karstens gives the area at 448,810 sq. kilometres (130,424 sq. geographical m.) and the volume at 206,901 cub. kilometres (32,413 cub. geographical m.), which gives a mean depth of 252 fathoms. Both these computations, however, were made before the date of the Austrian exploring expeditions (1896–98). Bludau's measurements give the total area draining to the Red Sea at about 255,000 sq. geographical m. Krümmel's more recent calculations (see ) give values somewhat higher than those of Karstens.

The Red Sea is formed by a line of fracture, probably dating from Pliocene times, crossing the centre of a dome of Archean

rocks, on both flanks of which, in Egypt and Arabia, rest Secondary and Tertiary deposits. The granite rocks forming the core of the dome appear at the surface on the Red Sea coast, at the western end of the transverse line of heights crossing Nejd. Along the line of fracture traces of volcanic activity are frequent; a group of volcanic islands occurs in 14° N., and on Jebel Teir, farther north, a volcano has only recently become extinct. The margin of the Red Sea itself consists, on the Arabian side, of a strip of low plain backed by ranges of barren hills of coral and sand formation, and here and there by mountains of considerable height. The greater elevations are for the most part formed of limestones, except in the south, where they are largely volcanic. The coasts of the Gulf of Akaba are steep, with numerous coral reefs on both sides. On the African side there are in the north wide stretches of desert plain, which towards the south rise to elevated tablelands, and ultimately to the mountains of Abyssinia. The shores of the Red Sea are little indented; good harbours are almost wanting in the desert regions of the north, while in the south the chief inlets are at Massawa, and at Kamaran, almost directly opposite. Coral formations are abundant; immense reefs, both barrier and fringing, skirt both coasts, often enclosing wide channels between the reef and the land. The reefs on the eastern side are the more extensive; they occur in places as much as 25 m. from the land. It has long been known that the whole Red Sea area is undergoing gradual elevation, and much has been done in recent years in investigating the levels of raised beaches found in different localities.

In the northern part, down to almost 19° N., the prevailing winds are north and north-west. The middle region, to 14°–16° N.,

has variable winds in an area of low barometric pressure, while in the southern Red Sea south-east and east winds prevail. From June to August the north-west wind blows over the entire area; in September it retreats again as far as 16° N., south of which the winds are for a time variable. In the Gulf of Suez the Westerly, or “Egyptian,” wind occurs frequently during winter, sometimes blowing with violence, and generally accompanied by fog and clouds of dust. Strong north-north-east winds prevail in the Gulf of Akaba during the greater part of the year; they are weakest in April and May, sometimes giving place at that season to southerly breezes. The high temperature and great relative humidity make the summer climate of the Red Sea one of the most disagreeable in the world.

The mean annual temperature of the surface waters near the head is 77° F.; it rises to 80° in about 22° N., to 84° in 16° N.,

and drops again to 82° at the Strait of Bab el-Mandeb. Daily variations of temperature are observable to a depth of over 50 fathoms. Temperature is, on the whole, higher near the Arabian than the Egyptian side, but it everywhere diminishes with increase of depth and latitude, down to 380 fathoms from the surface; below this depth a uniform constant temperature of 70.7° F. is observed throughout. In the Gulf of Suez temperature is relatively low, falling rapidly from south to north. The waters of the Gulf of Akaba are warmer towards the Arabian than the Sinai coasts; a uniform temperature of 70.2° is observed at all depths below 270 fathoms. 