Bay Of (Lat Bengal. Gangeticus Sinus), a gulf of the Indian ocean, embraced between the peninsula of Hindustan on the west and the coast of Lower Siam, Tenasserim, Pegu, and Aracan on the east. With the exception of the Arabian sea, it is the largest indentation on the southern coast of Asia, its width at the broadest part, from Cape Comorin at the southern extremity of Hindostan to the same latitude on the coast of Siam, being 1,400 m. From this point it continues of nearly uniform width to the parallel of Cape Negrais, lat. 16° 1' N., whence it contracts until the opposite coasts are but 250 m. apart, and terminates in an inlet or indentation of its N. shore, about 50 m. wide, and thickly studded with islands. All that part of the bay lying S. of the parallel of Cape Negrais is distinguished by some hydrographers as the sea of Bengal. The bay (in its wider meaning) receives the waters of many important rivers, among which are the Ganges, Brahmapootra, Hoogly, Irrawaddy, Godavery, and Kistnah. The tide in some places rises at times 70 or 80 feet. On the W. coast there arc no good harbors, and no soundings at the distance of 30 m. from land; but on the E. side there are several safe ports, and soundings within 2 m. of the shore.

The S. W. monsoon begins to blow on the W. or Coro-mandel coast about the end of March or early in April. In June it acquires its greatest strength and regularity; in September it subsides; and in October the N. E. monsoon commences, from which time till Dec. 1 navigation in the gulf is fraught with great danger. During the prevalence of both these winds a heavy surf rolls along the entire W. coast, rendering access to the rivers extremely difficult.