OB, or OBI, a river of West Siberia, known to the Ostiaks as the As, Yag, Kolta and Yema; to the Samoyedes as the Kolta or Kuay; and to the Tatars as the Omar or Umar. It is formed, 8 m. S.W. of Biysk in the government of Tomsk, by the confluence of the Biya and the Katun. Both these streams have their origin in the Altai (Sailughem) Mountains, the former issuing from Lake Teletskoye, the latter, 400 m. long, bursting out of a glacier on Mount Byelukha. The Ob zigzags W. and N. until it reaches 55 N.; thence it curves round to the N.W., and again N., wheeling finally eastwards into the Gulf of Ob, a deep (600 m.) bay of the Arctic Ocean. The river splits up into more than one arm, especially after receiving the large river Irtysh (from the left) in 69 E. Other noteworthy tributaries are: on the right, the Tom, the Chulym, the Ket, the Tym and the Vakh; and, on the left, the Vasyugan, the Irtysh (with the Ishim and the Tobol) and the Sosva. The navigable waters within its basin reach a total length of 9300 m. By means of the Tura, an affluent of the Tobol, it secures connexion with the Ekaterinburg-Perm railway at Tyumen, and thus is linked on to the rivers Kama and Volga in the heart of 'Russia. Its own length is 2260 m., and the area of its basin 1,125,200 sq. m. A system of canals, utilizing the Ket river, 560 m. long in all, connects the Ob with the Yenisei. The Ob is ice-bound at Barnaul from early in November to near the end of April, and at Obdursk, 100 m. above its mouth, from the end of October to the beginning of June. Its middle reaches have been navigated by steamboats since 1845.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)