ATLANTES, figures of men used in architecture instead of pillars.

ATLANTIC, THE, the most important, best known, most traversed and best provided for traffic of all the oceans on the globe, connecting, rather than separating, the Old World and the New; covers nearly one-fifth of the surface of the earth; length 9000 m., its average breadth 2700 m.; its average depth 15,000 ft., or from 3 to 5 m., with waves in consequence of greater height and volume than those of any other sea.

ATLAN`TIS, an island alleged by tradition to have existed in the ocean W. of the Pillars of Hercules; Plato has given a beautiful picture of this island, and an account of its fabulous history.  THE NEW, a Utopia figured as existing somewhere in the Atlantic, which Lord Bacon began to outline but never finished.

AT`LAS, a Titan who, for his audacity in attempting to dethrone Zeus, was doomed to bear the heavens on his shoulders; although another account makes him a king of Mauritania whom Perseus, for his want of hospitality, changed into a mountain by exposing to view the head of the Medusa.

ATLAS MOUNTAINS, a range in N. Africa, the highest 11,000 feet, the GREATER in Morocco, the LESSER extending besides through Algeria and Tunis, and the whole system extending from Cape Nun, in Morocco, to Cape Bon, in Tunis.

ATMAN, THE, in the Hindu philosophy, the divine spirit in man, conceived of as a small being having its seat in the heart, where it may be felt stirring, travelling whence along the arteries it peers out as a small image in the eye, the pupil; it is centred in the heart of the universe, and appears with dazzling effect in the sun, the heart and eye of the world, and is the same there as in the heart of man.

AT`OLL, the name, a Polynesian one, given to a coral island consisting of a ring of coral enclosing a lagoon.

ATOMIC THEORY, the theory that all compound bodies are made up of elementary in fixed proportions.

ATOMIC WEIGHT, the weight of an atom of any body compared with that of hydrogen, the unit.

ATRA`TO, a river in Colombia which flows N. into the Gulf of Darien; is navigable for 200 m., proposed, since the failure of the Panama scheme, to be converted, along with San Juan River, into a canal to connect the Atlantic and the Pacific.

A`TREUS, a son of Pelops and king of Mycenae, who, to avenge a wrong done him by his brother Thyestes, killed his two sons, and served them up in a banquet to him, for which act, as tradition shows, his descendants had to pay heavy penalties.

ATRI`DES, descendants of Atreus, particularly Agamemnon and Menelaus, a family frequently referred to as capable of and doomed to perpetrating the most atrocious crimes.

AT`ROPOS, one of the three Fates, the one who cut asunder the thread of life; one of her sisters, Clotho, appointed to spin the thread, and the other, Lachesis, to direct it.