Auser

• a tributary stream of the river Arno, in Etruria, near Lucca, now Serchio, Plin. 3, 5, 8, § 50; cf. Mann. Ital. I. p. 350.

➳ Ausur Rutil. Red. 1, 566.

AUSER or AUSAR (Αἴσαρ, Strab.: Serchio), a considerable river of Etruria, rising in the Apennines on the borders of Liguria, and flowing near the city of Luca, is evidently the same with the modern Serchio, though that river now flows into the Tyrrhenian Sea by a separate mouth, seven miles N. of that of the Arno, while all ancient writers represent the Auser as falling into the Arnus. The city of Pisae was situated at the point of their junction: and the confluence of the two streams was said to give rise to a violent agitation of their waters. (Strab. 5. p. 222; Plin. Nat. 3.5. s. 8; Rutil. Itin. 1.566.) The Auser appears to have retained its ancient course till about the 12th century; but the exact period of the change is unknown; the whole space between it and the Arnus, in the lower part of their course, is so flat and low that it is said that their waters still communicate during great floods. A canal or ditch between the two streams still retained the name of Osari in the days of Cluverius. The modern name of Serchio is supposed to be a corruption of Auserculus, a form which is found in documents of the middle ages. (Cluver. Ital. p. 462; Müller, Etrusker, p. 213; Targioni-Tozzetti, Viaggi in Toscana, vol. 2. p. 146--178.)