“ The Amur proper flows at first in a south-easterly direction for about 800 m., as far as long. 132° E., separating Manchuria from the Amur government; it then turns to the north-east, cuts its way through the Little Khingan mountains in a gorge 2000 ft. wide and 140 m. long, and after a total course of over 1700 m. discharges into the Sea of Okhotsk, opposite to the island of Sakhalin. It is estimated to drain an area of 772,000 sq. m. Its principal tributaries from the south are the Sungari, which the Chinese consider to be the true head-river of the Amur, and the Usuri ”