A river which rises in the mountainous region that borders the plateau of Gobi, its head-waters collecting in Lake Baikal, and after a course of 3200 m. through the centre of Siberia, falls by a long estuary or gulf into the Arctic Ocean; it is the highway of a region rich in both mineral and vegetable products, the traffic on which is encouraged by privileges and bounties to the trader at the hands of the Russian government.