Red Sea
2 of the 7 encyclopedias on this shelf carry an entry for Red Sea. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
an arm of the Indian Ocean, running N. N. W. from the Gulf of Aden, Aden, with with which it communicates by the Strait of Bab-el-Mandeb, 13½ miles across. Its length is about 1,200 miles, and its width in the central portion is between 100 and 200 miles, the greatest breadth being about 205 miles; it narrows toward the S. entrance, while in the N. it is divided by the peninsula of Sinai into two gulfs, the Gulf of Suez, 170 miles long by 30 miles wide, and the Gulf of Akaba, 100 miles in length. The Arabian coasts of the Red Sea are usually narrow, sandy plains backed by ranges of barren mountains; the African , coasts toward the N. are flat and sandy but farther S. high table-lands rise some distance inland, culminating still farther S. in the lofty mountains of Abyssinia. A marked feature in the configuration of the Red Sea is found in the large existing and upraised coral reefs running parallel to both the E. and W. shores, those to the E. being more extensive and farther from the coast than those to the W.; the most important are the Farsian Archipelago in the E. reef, and the large island of Dahlak, lying off Annesley Bay, in the W. reef. In addition to the islands of organic formation mention may be made of the volcanic group lying in lat. 14° N., the largest of which, Jebel Zugur, is 10 miles long, 7 miles wide, and 2,074 feet in height; farther N., on the islet of Jebel Teir, eir, is a volcano which was active till quite recently. A dangerous reef, the Dædalus, lies directly in the path of steamers in lat. 2412° N., and a lighthouse has been placed on it. The principal harbors on the Red Sea are Mocha, Hodeida, Lokeyyah, Jiddah, and Yenbo, on the Arabian coast, and Massowah, Khor Nowarat, and Suakim on the African coast. In ancient times the Red Sea was used as a means of communication by the Phœnicians and other maritime peoples, till the discovery of the route round the Cape of Good Hope diverted the traffic into another channel, only to be revived, however, on a much more extensive scale with the construction of the Suez Canal. The tide; are very variable, depending largely on the direction and force of the winds, which also to a great extent determine the direction and velocity of the surface currents. The hot climate is due to the almost cloudless sky, and consequent want of rain, the altitude of the sun, and the absence of rivers. The mean temperature of the air generally ranges between 70° and 94° F. during the day , though readings of over 100° are often registered in the shade; but during the night the temperature may fall to the freezing point, owing to radiation in the clear atmosphere. The prevailing wind on shore is N. N. W. almost universally, but from October to May S. S. E. winds prevail over the S. portions of the sea, a belt of calms and variable winds occurring in the central regions, while the N. portions the usual N. N. W. winds are met with. Evaporation is very great, and the air over the water is always very moist in the summer; hurricanes are unusual, but rain squalls frequently occur with the S. winds, and moderate gales and sandstorms , called "dragons" in the popular language of the Arabs, are not uncommon. The temperature of the water below the surface decreases down to a depth of about 200 fathoms, from whence down to the bottom a mean temperature of about 71° is found all the year round; this agrees with the temperature conditions prevailing in the inclosed seas of the East Indies, for instance, according to the observations made on board the "Challenger," the depth at which the minimum temperature occurs (i. e., 200 fathoms in the Red Sea) indicating the depth of water over the barrier separating the sea from the open ocean. In Vol. VII-Cyc winter, in the N. part, the whole body of water from surface to bottom usually has a mean temperature of 71°. The salinity of the water is almost constant at about 1.030 (ordinary ocean water is about 1.026), and this is due to the fact that no rivers flow into it, little rain falls, and the evaporation is excessive. It has been estimated that, were the Red Sea entirely inclosed, it would become a solid mass of salt in less than 2,000 years, but this is prevented by an inflow of water through the Strait of Bab-el-Mandeb, and it is also known that a current of very salt water flows out underneath the incoming surface current. The greatest depth in the Red Sea is about 1,200 fathoms, and the mean depth of the whole area about 375 fathoms. From the point of greatest depth, which is near the center, the bottom rises toward each end. Owing to the absence of rivers the deposits approach in character those formed in the open ocean, being largely composed of Foraminifera, Pteropods, and other pelagic shells. The marine fauna and flora are extensive, and have been described by Haeckel and other naturalists; it has been shown that a migration of the Red Sea and Mediterranean faunæ is taking place along the Suez Canal. The path by which the Israelites went out of Egypt was along the course of the valley called Wady Tumeilât, apparently an old arm of the Nile now silted up. The Lake of Ismailieh (Timsah) was then most probably the head of the Gulf of Suez, but the exact point of passage of this arm of the sea still remains obscure.
Aiton's Encyclopedia (1910)
a branch of the Indian Ocean , known also as the Arabian Gulf. It lies between Arabia on the east and Abyssinia and Egypt on the west. Its extreme length from the entrance of the Suez Canal to the Strait of Bab-el-Mandeb is about 1,450 miles. Its general width is less than 200 miles. The narrowest part of the strait mentioned is less than fifteen miles. A branch about 100 miles in length extends northeastward into Arabia. The waters contain reddish marine algae, whence the name. The Red Sea occupies a long trough or valley. The shores are low and sandy, sometimes swampy. Travelers by steamer catch sight occasionally of a skulking lion. Considerable areas of sea are quite shallow. It is said that during the prevalence of heavy winds from a certain quarter, it may be possible to ford an arm of the sea. The Israelites are reputed to have crossed dry-shod from Egypt to the southern point of the peninsula which lies between the so-called Gulf of Suez and the Arabian branch of the Red Sea. The climate of the Red Sea region is excessively hot and rainless. It is estimated that the annual evaporation from the surface of the sea ranges from eight to twenty-three feet a year, according to locality. A large part of the moisture is carried by northwestern winds to the Abyssinian mountains, where it is deposited in the form of a perpetual snowcap. If the straits of Bab-el-Mandeb were closed, the sea would be converted into a bed of salt in from 1,000 to 2,000 years. See Suez Canal ; Sinai