ANDERNACH, a small town of Rhenish Prussia, situated on the left bank of the Rhine, 10 miles north-west of Coblenz. It is the Antunnacum of the Romans, and in the Middle Ages was a fortified town of considerable im portance, but at the present day the walls only add to its picturesque appearance. Among the objects of interest are a lofty watch tower, the Coblenz gate, and the fine parish church, built in the beginning of the 13th century. Andernach has a trade in leather, corn, and wine; but its most noted articles of commerce are millstones, made of lava and of tufa-stone, which when pounded and mixed with lime, possesses the property of hardening under water, and has been much used by the Dutch as a cement in the construction of their dykes. Population about 4000.