BRAHMAPUTRA, one of the largest rivers of India, with a total length of 1800 miles, rises near the lake Mansarowar in the plateau of Thibet, where it is known by the name of Sanpu, flows eastward for about 1000 miles, and skirting round the eastern passes of the Himalayas not far from the Yang-tse-kiang and the great river of Cambodia, enters the plain of British India on the north-eastern frontier of Assam. It then runs westward, dividing the province of Assam into two unequal portions, turns southward into Eastern Bengal, and joins the Ganges opposite Goalanda, the terminus of the Eastern Bengal Railway. The united stream then flows south-west, joins the Meghnd, and after another southern stretch of about 100 miles, empties itself into the Bay of Bengal. The body of water formed by the union of these three noble rivers, the Brahmaputra, Ganges, and Meghna, expands during the latter part of its course into a vast estuary, studded with large islands. The Brahmaputra proper in Assam is formed by the union of three streams, in 27° 45' N. lat. and 95° 30' E. long.,the Sanpu or Dihang, the Dibang, and another stream, which, although the least of the three, the Hindus have taken as the main branch, honouring it with the name of Brahmaputra, and sanctifying it in their mythology. This branch, which many European writers have accepted as the main Brah-maputra, takes its rise in a valley called the Brahmakunda, on the side of the eastern extremity of the Himalaya Mountains beneath the snowy range.
The upper part of the Brahmaputra is entirely in Thibet, and divides the broad plateau drained by the very elevated Thibetian lakes from the narrow plateau which divides the northern and southern Himalayan ranges, where the affluents of the Ganges spring from perennial snow. At the western extremity of the Brahma-putra basin the main river is 14,000 feet above the sea, and after a course of 600 miles it is still ll.OOO.feethigh. Nothing is known of its passage across the Himalaya Mountains. The features of the passage are probably similar to those exhibited by the gorge of the Sutlej; but it is a reproach to the science and enterprise of the 19th century to allow such a problem to remain unsolved. Eastward the basin of the Brahmaputra is bounded by that of the Yang-tse-Kiang, which here flows through tremendous gorges on its way to the plains of China and the Yellow Sea. Some contend that the basins of the Irawadi, Salwin, and Cambodia rivers, are interposed between the Brahma-putra and the Yang-tse-Kiang, although they approach each other within 150 miles. On the south, the Patkai Mountains, terminating in the Manipur and Chittagong hills, separate the Brahmaputra from the Irawadi and the basins of the Arakan coast. The principal tributaries of the Brahmaputra are the Dibru, Buri Dihing, Disang, Subansiri, Manas, Baghmi, Dharla. and Tista. The Brahmaputra forms many islands during its course; among which that of Majuli, enclosed by the Brahmaputra and its branch the Lohit, contains an area of 282,165 acres, and is well inhabited and cultivated. In Assam, the Brahmaputra also bears the name of the Hiranya, and above its junction with the Ganges it is called the Jamuna. The principal towns on its banks in Assam are Dibrugarh, Tezpur, Gauhati, Goalpara, and in Bengal Sirajganj. Its volume of water has been computed at Goalpara during its lowest ebb at 146,188 cubic feet per second. During the rains, when the river attains a height of 30 to 40 feet above its common level, its body of water may fairly be computed at four times the above quantity. The Brahma- putra is navigable as far as Dibrugarh, but in the dry season only for steamers of light draught. In the rains it overflows its banks and spreads over the countiy for hundreds of square miles. At Goalanda, where it joins the Ganges, the current is so strong during the rains, and the eddies and whirlpools formed by the meeting of the waters- so numerous, that large and powerful river steamers are often unable to make headway, and have to lie for days until the river subsides. The main branch of the Brahmaputra formerly flowed through the eastern district of Maimansinh, but the greater part of its water now finds its way through the Jamuna. The total length, as above stated, is 1800 miles; but if its source be taken at the Brahmakunda, the length of the river only amounts to 930 miles. Until 1765 the Brahmaputra River was unknown in Europe as a first-class river, and Major Rennel, on exploring it, was surprised to find it larger than the Ganges. The bore, or upward wave caused by the sudden influence of the tide, occurs in all the passages between the islands of the estuary formed by the united streams of the Brahmaputra, Ganges, and Meghna. (W. W. H.)