ACHEEN. See Ach í n.

ACHELOUS, the largest river in Greece, rises in Mount Pindus, and dividing Aetolia from Acarnania, falls into the Ionian Sea. In the lower part of its course the river winds in an extraordinary manner through very fertile but marshy plains. Its water descends from the mountains, heavily charged with fine mud, which is deposited along its banks and in the sea at its mouth, where a number of small islands have gradually been formed. It was formerly called Thoas, from its impetuosity in its upper portion, and Homer gave it the name of king of rivers. It has a course of 130 miles. The epithet Acheloius is used for aqueus (Virgil), the ancients calling all water Achelous, according to Ephorus. The river is now called Aspro Potamo.

ACHENWALL, Gottfried, a German writer, celebrated as having formulated and developed the science (Wissenschaft der Staaten), to which he was the first to apply the name scientia statistica, or statistics. Born at Elbing, in East Prussia, in October 1719, he studied at Jena, Halle, and Leipsic, and took a degree at the last-named university. He removed to Marburg in 1746, where for two years he read lectures on history, and on the law of nature and of nations. Here, too, he commenced those inquiries in statistics by which his name became known. In 1748, having been invited by Münchhausen, the Hanoverian minister, to occupy a chair at the university, he removed to Göttingen, where he resided till his death in 1772. His chief works were connected with statistics. The Staatsverfassungen der europäischen Reiche appeared first in 1752, and revised editions—corrected from information which he travelled through England, France, and other countries to collect—were published in 1762 and 1768. He was married in 1752 to a lady named Walther, who obtained some celebrity by a volume of poems published in 1750, and by other writings.

ACHERON, in Classical Mythology, the son of Ceres, who, for supplying the Titans with drink when they were in contest with Jupiter, was turned into a river of Hades, over which departed souls were ferried on their way to Elysium. The name eventually was used to designate the whole of the lower world.