BED KIVER OF THE NORTH. 772 RED SEA. •few mik's fiom the sources of the ilississippi (Map: North Dakota, HI). It flows first south- ward through a chain of numerous lalces, then westward to the boundary between Minnesota and North Dakota, which it follows in a north- erly course until it enters Manitoba, where it empties into the southern extremity of Lake Winnii)eg. Its length is about 700 miles. Its course lies through an almost perfectly level plain which was formerly the bottom of Lake Agassiz (see Lake), and which is a famous wheat-producing region. The river and its liranches have cut narrow channels through the plain with clay banks 20 to 60 feet high. The southern branch of the Red River connects through Lake Trav.erse with the Minnesota and Mississippi rivers, so thiit during high water small steamers may sometimes pass from the Mississippi to Lake ^Yinnipeg. Owing to the diflference in latitude between the upper and lov.er courses, spring sometimes arrives at the former while the latter is still ice-bound, so that the waters are piled up and inundate the plain. REDROOT. A popular name for various un- related plants. One of the best known is Lach- vanthrf: tinctoria, of the natural order Hiemodo- REUBOOT (^Lachnanthes tinctoria). raceae, which grows in wet sandy soils near the coast of the Eastern United States. It has sword-shaped leaves mostly close to the ground, and an unbranched almost leafless stem which bears at its summit a dense compound cyme of woolly yellow flowers. The perennial roots con- tain a red coloring matter sometimes used in dyeing. Alkanet (Alkanna ot Aiichusci tinctoria) , certain American pigveeds (Amarantns spp. ), and Ccanothus Americanus are also called red- root. See Ce.xothus; Alkanet; Amaranth. RED'RTJTH. A town in Cornwall. England, the centre of a famous mining district. 9i/.> miles northwest of Falmouth (Map: England, A 6). In 1792 gas was first used here for lighting purposes. Tin. from numerous mines in the vicinity, is smelted in the town, and iron foun- dries are in operation; another important prod- uct is copper. Population, in 1891, 10.324; in 1901, 10,4r)0. RED SANDSTONE. A term formerly ap- plied to the combined Devonian and Permian rocks, when their relations to the Carboniferous .strata were unknown. The discovery that oe set of the Ked Sandstone w'as below the coal, while the other was above it, caused the division into the Old Red Sandstone, or Devonian, and the New Red. or Permian. For some time after tills division, the original term was retained by a few geologists, but it is now quite given up. See Old Red Sandstone; Permian System. RED SCALE. The name applied in Florida to Afipidiulus fictis, and in California to Aspidi- otus citri, two common and destructive enemies of the orange. See Orange Insects. RED SEA (Lat. Mare Riiinim, Gk. 'EpvSpri edXao-ffa, Erythre Thalassa), or Arabian Gulf. An arm of the Indian Ocean separating the Arabian peninsula from Northeastern Africa, and lying between latitudes 12° 30' and 30° N. (Map: Asia, C 6). It extends in a northwest direction from the Strait of Bab-el-Mandeb, 20 miles wide, through which it communicates with the (iulf of Aden, to the Isthmus of Suez, and is 1380 miles long. It is narrowly elongated in shape, with a breadth between 100 and 200 miles maintained for the greater part of its length. In the north the sea divides into two arms, cutting off the Sinai Peninsula : these are the Gulf of Suez in the west, 170 miles long and 25 miles wide, and the Gulf of Akabah in the east, 110 miles long and 12 miles wide. The Gulf of Suez is connected by the Suez Canal (q.v. ), about 100 miles long, with the Mediterranean. The basin of the Red Sea is formed by a line of fracture running through the great Archaean mass capped by the limestone plateaus of Egj-pt and Arabia. The Archa>an rocks are exposed here and there along the coast. A branch fissure with steep rocky sides forms the Gulf of Akabah, and runs northward as the depression called EI-Arabah, the deep sink of the Dead Sea, and the valley of the Jordan. The shores of the Red Sea are bordered on the Ara- bian side by sandy deserts, which form a narrow strip backed by the limestone range. On the Egyptian side there are wide, sandy plains in the north, rising farther south into elevated table- lands, and finallj' into the mountains of Abys- sinia. Each shore, particularly the eastern, is lined with immense coral reefs which in some places extend 25 miles or more from land. They liave occasioned numerous islands and archipela- goes. The principal groups are the Farsan Isl- ands near the Arabian shore and the Dahlak Isl- ands near the African. The mean depth of the Red Sea is about 2000 feet. Through the greater ])art of its length runs a central channel with
- i depth exceeding 3000 feet, divided by compara-
tively shallow ridges into three basins, of which the northern and southern have a maximum depth of about 4200 feet, and the central of near- Iv 7500 feet. The Strait of Bab-el-Mandeb is 1200 feet deep. In the Gulf of Suez the depth is scarcely more than 200 feet. The mean temperature of the surface water is 77° in the north, 80° near the middle, and 84°
