ATALANTIS, or ATLANTICA, an island mentioned by Plato and some others of the ancients, concerning the real existence of which many disputes have been raised. Homer, Horace, and the other poets make two Atlantics, calling them Hesperides and Elysian Fields, and representing them as the habitations of the blessed.

The most distinct account of this island we have in Plato's Timaeus, of which Mr Chambers gives the following abridgment:—

"The Atlantis was a large island in the Western Ocean, situated before or opposite to the Straits of Gades. Out of this island there was an easy passage into some others, which lay near a large continent, exceeding in size all Europe and Asia. Neptune settled in this island (from whose son Atlas its name was derived), and divided it amongst his ten sons. To the youngest fell the extremity of the island, called Gadir, which, in the language of the country, signifies fertile, or abundant in sheep. The descendants of Neptune reigned here, from father to son, for a great number of generations, in the order of primogeniture, during the space of nine thousand years. They also possessed several other islands; and passing into Europe and Africa, they subdued all Libya as far as Egypt, and all Europe to Asia Minor. At length the island sunk under water; and for a long time afterwards the sea thereabouts was full of rocks and shelves." Many of the moderns also are of opinion that the existence of the Atlantis is not to be looked upon as entirely fabulous. Some take it to have been America; and on this supposition, as well as from a passage in Seneca's Medea, and other obscure hints, they imagine that the new world was not unknown to the ancients. But allowing this to be the case, the above-mentioned continent, which was said to lie beyond Atlantis, would seem rather to have been the continent of America than Atlantis itself. The learned Rudbeck, professor in the university of Upsal, in a work entitled Atlantica sive Manhein, endeavours to prove that Sweden and Norway are the Atlantis of the ancients; but the situation assigned to it renders this notion untenable. Kircher supposes it to have been an island extending from the Canaries quite to the Azores; adding, that it was really swallowed up by the ocean, as Plato asserts, and that these small islands are the shattered remains of it which were left standing.