Dardanelles
2 of the 7 encyclopedias on this shelf carry an entry for Dardanelles. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
(the ancient Hellespont), a narrow channel separating Europe from Asia, and uniting the Sea of Marmora with the Archipelago. The name is derived from the ancient city of Dardanus in the Troad, on the S. shore; and Dardanus was named from the Dardani, an ancient people farther inland. The strait extends from N. E. to S. W., and has a length of about 40 miles, and a breadth varying from 1 to 4 miles. From the Sea of Marmora a strong current runs through the strait to the Archipelago. Both sides are strongly fortified. A treaty concluded between the five great powers and Turkey in 1841 arranged that no ship of war belonging to any nation save Turkey should pass the Dardanelles without the express consent of Turkey; all merchant-ships being also required to show their papers to the Ottoman authorities. These provisions were confirmed at London in 1871 and at Berlin in 1878, in February of which year a British fleet had sailed into the Sea of Marmora. The Dardanelles is celebrated in ancient history on account of Xerxes and Alexander having crossed it, the former in 480 B. C. to enter Europe; and the latter in 334 B. C. to enter Asia. The point at which Xerxes crossed, by two separate bridges, was in the neighborhood of Abydos, on the Asiatic shore, opposite to Sestos. Alexander crossed at nearly the same place; and here also young Leander nightly swam across to visit Hero-a feat performed in 1810 by Lord Byron. The attempt by British and French fleets to force the Dardanelles, in connection with the attempted capture of the Gallipoli peninsula, constituted one of the most important operations of the first two years of the World War. See WORLD WAR; TURKEY.
Aiton's Encyclopedia (1910)
dar-da-nelz, the Hellespont of the ancients, a narrow strait connecting the Sea of Marmora with the Mediterranean and separating Europe from Asia. It is forty miles in length and from one to four in width. A swift current runs westward at all seasons of the year. Xerxes, the Persian, led his host across the Hellespont by means of two bridges, resting on boats. According to Herodotus the bridges groaned beneath the living tide of Asiatics for seven days and nights. In 1811 the poet Byron swam across from Abydos to Sestos in a little over an hour. This he did in emulation of the legendary Leander, who used to swim across to visit Hero, and who in so doing lost his life. The strait is wholly within the Turkish dominions and is strongly fortified on both sides by works and heavy batteries of Krupp guns. By treaties of 1841, 1856, and 1878, the powers have agreed that warships shall not be allowed to pass the Dardanelles. The measure is designed to protect the Porte, and especially to deny the Russians access to the Mediterranean. See Constantinople