RED SEA, the Arab Bahr-el-Ahmar, or Bahr-el Hejaz, the ancient Sinus Arabicus, is an arm of the sea extending from the Arabian Sea towards the N.W. between Arabia and Africa to a distance of 1400 miles. It is entered at tho south extrem ity by a strait, the Bab-ul-Mandab, 18 miles in width. At the broadest part (lat. 16° N.), it is 221 miles in width. Towards the north end it gradually contracts, and at length divides into two arms,—the Gulf of Akaba (Sinu.s Aelanites) and the Gulf of Suez (Sinus Ileroopolites), the Bahr Suez or Bahr Kulztun (so called after the ancient Klysma). The sea averages 400-600, and is at places 1054 fathoms in depth, but the shores are flanked with a network of coral reefs and islands which often extend a long way from the coast. Its area is 123,500 square geo graphical miles. No rivers fall into the Red Sea, but a number of intermittent rain torrents descend from its btuiks.
The colour of the water changes with the depth. It is of a blue colour changing to pale green where there are shoals or reefs near tho surface, but varies also with the changing winds and colour of the sky. No satisfactory reason for the modern name of the sea has yet been given. Iu the deep water, the colour does not vary more than iu other seas. But the name ham led to sunniaca. One Aug gestion has been the prevalence of the Oacillatoria rubescens of Ehrenberg, who, while nailing in thin sea, observed that the occasional red colour of its waters was causal by enormous quantified' of this animal, which gee= to be the Name witlt what Haller described as a purple conferra swimming in water. Tito alleged red colour ix, however, aleo supposed to be from the Trichodanninin cry thrteurn, filamentotui alga. It is described as of a blood-rol colour, often cover* large art-sa, and appears and disappeara somewhat atpricioualy. It has as synonym T. Eltrenbergii. T. Ilindlii, also of a blood-red colour, has been found off the west coast of South America. Under the micro scope, the Trichodesmium seema like sheaves of minute fibres. Dr. Collingwood, however, men tions that he had never seen red Trichodeamiutn, or any tint of red. He had seen it yellowish brown. Ile had seen tho Indian Ocean red from myriads of minute red crustacea, and the sea in the Formosa. Channel red from gelatinous worms, but never by Trichodesmium.
The difference between high and low tide is 3i to 7 feet. The prevalent wind in the north part of the sea is from the north, and in the south part the S.E. wind in winter, and the N.W. in summer. The littoral consists of barren rock or sand. A little way inland the mountains rise to a height of 4000 to 7000 feet.
Much of the region is volcanic, and some of the islands still emit smoke. The island of Perim is trachytic ; the culminating points of the island reach an elevation of 228 feet, and prove that the island itself is the result of a volcanic eruption under the sea. The lava had first raised up tins large bank of Madrepore which covered the bottom, and had then forced its way through the inter stices, and become visible over the water. This volcano, the vast crater of which embraced the bay of Perim, in course of time covered the new island with mud, ashes, trachytie blocks, etc., and then became extinguished.
The fauna and flora of its coasts and seas have been described by several naturalists, who have noticed the flights from shore to shore of locusts and quails and pigeons.
So far back as the time of Solomon, the navi gation of the Red Sea was of importance, and several of the seaports, such as Berenike and Myoe Bonitos, were celebrated.
The commercial routes between the west and the east from _pre-historic times had been three, viz,. the Red by the Euphrates and Tigris, and Persian Gulf, all of them known to tho ancients as the Erythrean seas. Political changes led to some one of these being preferral, tho others being for centuries neglected, or even forgotten. Scylax had, by tho order of Darius, dropped down the river Indus, coasted Arabia, and thence reached tho Red Sea. It WAS tho wIsh of Alexander the Great to recover the Indian trade from the Sableans, and bring it through tho Red Sea, but his early death prevented this being attained. Eudoxus of Cyzicus in Asia Minor went to Alexandria to persuade Euergetes to give him tho command of a vessel for this voyage of discovery. A vessel was given him, and thoug,h he was but badly fitted out, he reached a country, which he called India, by sea, and brought back a cargo of spices and precious stones. lio wrote an account of the coasts which he visited, and it was made use of by Pliny.