MEKONG or ME NAM KONG (pronounced Kawng), some times known as the Cambodia River, the great river _ of Indo China, having its origin in the Tibetan highlands. It is one of the longest rivers in Asia. It is about 2,800 m. in length, of which 1,200 flow through portions of the Chinese Empire and Tibet and 1,600 through French territory. Its sources are supposed to rise on the slopes of Dza-Nag-Lung-Mung in about 33° N., 93° E., at an altitude of 16,700 ft. above sea-level. Throughout the greater part of its course in Tibet, where it is called the Dza-Chu, it flows south-eastwards to Chiamdo, on the great east and west caravan route from China to Lhasa. At this point it is about Io,000 ft. above sea-level. From here it flows southwards through little-known mountain wastes. Below Dayul in lat. 29° it is known by the Chinese name of Lantsan Kiang. For the next 300 m. of its course the Lantsan Kiang, or, as it soon becomes known among the Thai peoples inhabiting its rugged valley, the Mekong, is very little known to us. The river flows beneath bare and rocky walls with the speed of a mountain torrent, although at its exit from Chinese territory its width reaches 30o to 400 yds. In 25° 18' N. the Tali-Bhamo caravan route crosses the river by an iron suspension bridge at a height of 4,700 ft. above sea level. From this point to Chieng or Keng Hung, the head of the old confederacy of the Sibsawng Punna or Twelve States, it is little known ; the fact that it falls some 90o ft. for each degree of latitude indicates the character of the river, the course of which is constantly deviated by the varying directions of the mountainous massifs through which it passes. Under the provi sions of the Anglo-French agreement of January 1896, from the Chinese frontier southwards to the mouth of the Nam Hok the Mekong forms the frontier between the British Shan States on the west and the territories acquired from Siam by France in 1893. By the treaty of 1893, from that point southwards to about
3o' N. it is also the frontier between French Indo-China and Siam. Between the Siamese Shan town of Chieng Sen and Luang Prabang it is joined by some important tributaries: the Nam Beng, the Nam-Hou and the Nam-Khan. This portion is ob structed by rapids. From Luang Prabang the river cuts its way for two degrees through a lonely jungle country among receding hills of low elevation. From Chieng Khan the river forces its way through its most serious rapid-barrier, and receives some important tributaries from the highlands of Tung Chieng Kum and Chieng Kwang, the finest country in Indo-China. In 104° E. the river resumes its course through a country thinly peopled. At Kemarat (i6° N.) the fourth serious rapid-barrier occurs, some 6o m. in length, and the last at Khong in 14° N. From here to its outfall in the China Sea the river winds for some m. through the French territories of Cambodia, where it divides into three arms, and Cochin China, regions formed of the alluvium of the delta which is ceaselessly gaining on the sea. In origin a mountain stream, it becomes swollen at the melting of the snows. As a plateau river it is increased from June to October by the rains brought by the S.W. monsoon. From October to May it occupies only a portion of its bed. In the plain and delta part of its course, it floods, with its muddy waters, Cambodia and Cochin China, which owe to it their fertility. The French have done much to render the river navigable.