GEOGRAPHY. 245 



ASIA. 



Colonel Prjevalsky, who spent the winter of 1883-'84 at Chobsen, a 

 little to the eastward of Koko Nor, in Northeastern Tibet, resumed his 

 explorations in the middle of March, crossing the Tsaidam or country 

 west of the Kpko Nor. This region he describes as a vast salt-marsh 

 basin, the bed of a mighty lake at a comparatively recent geological 

 epoch, and having a height of 9,200 feet above the sea. At the begin- 

 ning of May the pass through the Burkhan Buddha Ridge was crossed 

 at a height of 15,700 feet, and the table land of Northern Tibet was 

 reached, a region quite unknown to geographers even now, and which 

 the Chinese have repeatedly but vainly attempted to explore. The 

 source of the Yellow or Hoang-ho River was found, about 70 miles south 

 of the Burkhan Buddha Ridge, at a height of 13,600 feet above the sea. 

 It is formed by two streamlets fed by springs in a wide, marshy valley. 

 After flowing about 14 miles it enters two wide lakes in succession, and 

 thence rushes furiously toward the boundaries of China proper. Colonel 

 Prjevalsky describes the climate of Northern Tibet as inclement in the 

 extreme. In the latter part of May wiutery snow-storms occurred and 

 the thermometer stood at — O^F. at night. Through May, June, and 

 July it rained every day, and sometimes for several consecutive days, 

 frosts (23° F.) occurring every clear night. The amount of rainfall caused 

 by the southwest monsoon in the Indian Ocean is so great that in sum- 

 mer Northern Tibet is almost one vast bog. Numerous herds of large 

 animals were seen— yak, wild asses, antelopes, and mountain sheep, and 

 bears were very frequently encountered, some thirty specimens being 



killed. 



From the sources of the Yellow River a route was followed southward 

 across the ridge separating the sources of the Yellow River from that of 

 the Blue River or Yang-tse-Kiang. Journeying southward 60 or 70 

 miles, the banks of the Blue River were reached; but as fording was 

 impossible, from the depth and rapidity of the current, the expedition 

 returned northward along the lakes at the head of the Yellow River. 

 These lakes, by right of discovery. Colonel Prjevalsky called Expedition 

 and Russian Lakes. They are 13,500 feet above the sea ; are each more 

 than 80 miles in circumference, and are surrounded by mountains. 



Fierce attacks were repeatedly made by the Tangutau robbers on the 

 little force, fourteen in number, but were bravely beaten off without 

 loss, and in July and August, 1884, the expedition returned to the plains 

 of Tsaidam. 



On their return journey a party of thirty gold- washers was found 

 at the southern foot of the Burkhan Buddha. At these diggings the 

 Tangutans went no deeper than 1 or 2 feet from the surface, and the 

 ' method of washing was of a very primitive character, but whole hand- 

 fuls of gold, in lumps as big as peas, were shown, and frequently much 

 larger nuggets. Colonel Prjevalsky reports gold as very plentiful, and 

 is of the opinion that with proper working vast treasures will be found 



