S. 0. Das— Identity of the great Tsang-po of Tibet. 
[No. 1 
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A Note on the Identity of the great Tsang-po of Tibet ivith the Bihong .— By 
Sarat Chandra Das, C.I.E., Rai Bahadur. 
[Eead February, 1897.] 
Sir Clements Markham, President of the Royal Geographical 
Society in his learned introduction to “ Narratives of the Mission of 
George Bogle to Tibet,” regarding the course of the Tsang-po wrote as 
follows :—•“ Beyond the point where the Lhasa route crosses the river, 
in longitude 90° 40' E., the course of the Brahmaputra within the 
mountains is entirely unknown for a distance of about 400 miles, when, 
under the name of Dihong, the mighty stream emerges into the valley 
of Assam and becomes the Brahmaputra of the plains. Yet there can 
be no reasonable doubt that the Tsang-po of great Tibet and the Brahma¬ 
putra of the plains are one and the same river.” 
This question has occupied the attention of geographers for 
upwards of a century. In his instructions, dated 1774, Warren Hastings 
specially enjoined Mr. Bogle to inform himself respecting the course of 
the Brahmaputra. D’Anville, and afterwards Klaproth, believed that 
the Tibet river was the upper course of the Irrawaddy. In 1825 Captains 
Bulton and Wilcox were sent to explore its course. Bulton followed up 
the course of the Dihong, until he was stopped by wild tribes, while 
Wilcox crossed the water-parting towards Burma, and reached the 
banks of the Irrawaddy. From the point reached by Bulton on the 
Dihong, to the place where Manning crossed the Tsang-po, there is an 
interval of about 400 miles, and a difference of level of 11,000 feet. This 
interval was entirely unknown till 1882 when I explored up to Saugri 
Khamar, a place situated to the east of the to svn of Chethang on the 
Tsang-po where it crosses 92° Lg., and Lama Ugyen Gyatsho, about 50 
miles further east up to the confines of the province of Kongbu; and 
Kunthup has done, though not scientifically, further 200 miles, so that 
out of 400 now only about 50 miles remain to be explored. 
In July 1880, a Lama of Gya-rong was despatched by the late 
