Don. I. A River Of Russia, the Tanais of the ancients, and the Tuna, Duna, or Dana of the Tartars. It is one of the largest rivers of Europe. It rises in a small lake in the government of Tula, flows S. E. and S. W., passes Voronezh, Pavlovsk, Novo-Tcherkask, Tcher-kask, Nakhitchevan, Rostov, and Azov, and enters the sea of Azov by three mouths, only one of which is navigable. Its length, including windings, is nearly 1,000 m., though from its mouth to its source in direct line is but 468 m. In summer navigation is difficult, but in winter the water is high enough, and the stream becomes navigable to Zadonsk, about 800 m. from its mouth. The course of the river lies through a low country, covered with vast forests of oak and pine. The current is sluggish, and sand banks, over which there are often only two feet of water, are of frequent occurrence. Opposite Dubovka the Don approaches the Volga to within 40 m., and a railroad connects the two rivers between Ka-latch and Tzaritzin. The principal tributaries are the Sosna and the Donetz on the right, and the Voronezh (or Voronetz), the Khoper, the Medvieditza, the Sal, and the Manitch on the left. II. A river of Aberdeenshire, Scotland, next to the Dee in size, but of little commercial importance.

It rises on the declivity of Ben Aven, flows a tortuous easterly course of about 70 m., and enters the North sea near Aberdeen. It is navigable for a very short distance from the sea. Near its mouth stands the celebrated one-arched Gothic bridge of Balgownie. A handsome new bridge of five arches has been built a little below the old structure. The salmon fisheries of the Don are of considerable value. III. A river of Yorkshire, England, 55 m. long, rising near the borders of Cheshire, and flowing into the Ouse. It is navigable from Sheffield, a distance of 40 m., and communicates by canal with the Trent and the Calder.