MEGHNA  , a

river of India . It forms, in the lower part of its course, the great estuary of the Bengal delta, which conveys to the sea the main body of the waters of the Ganges and the Brahmaputra, which unite at Goalanda in Faridpur district . The united waters, turbid and of great depth, are sometimes split into half a dozen channels by sand-banks, sometimes spread into a wide sheet of water . The river enters the sea by four principal mouths, enclosing the three large islands of Dakshin Shahbazpur, Hatia and Sandwip . It is navigable by native boats and river steamers all the year; but the navigation is difficult and some-times dangerous on account of shifting sand-banks and snags, and boisterous weather when the monsoon is blowing . The most favourable season is between November and February . AlIuvion and diluvion are constantly taking place, especially along the seaboard, and in Noakhali district the land is said to have made rapid advance on the sea; while the islands fringing the mouth are annually being cut away and redeposited in fresh shapes . The regular rise of the tide is from To to 18 ft., and at springs the sea rushes up in a dangerous bore . It is greatest at the time of the biennial equinoxes, when navigation is sometimes impeded for days together . The tidal wave advances like a wall topped with foam of the height of nearly 20 ft., and at the rate of 15 M. an hour; in a few minutes it is past, and the river has changed from ebb to flood tide . A still greater danger is the " storm wave " which occasionally sweeps up the Meghna under a cydone .