These deltas,—for we wish to explain as we go along, and would rather fall into the error of explaining where there is no necessity, than of leaving one word that might prove a stumbling-block unexplained,—these deltas are all the mouths, (_les embouchères_,) of _oceanic_ rivers, that is, of rivers that pursue their impetuous course towards their native ocean bed; and the character of these deltas necessarily varies with the character of the coast through which they pursue the _un_even “tenor of their way.” As the level of the sea is approached, the rapidity of the mountain stream is necessarily checked. No longer dashing down steep mountain precipices, as it did in the heyday of its youth, it finds itself grown into a majestic breadth and depth; and as it nears its maternal home, leaving the high land of its origin far behind, it traverses with slow and measured pace the slightly descending planes by which it falls into the ocean. This gradual process enables it to deposit on each side the alluvial soil, and decayed vegetable matter, and so on, that have been held by it in suspension during its rapid progress; and as the current slackens still more as it approaches its final destiny, portions of land gradually rise into view, the results of these deposits, which from their triangular shape have received the name of deltas, from their likeness to the Greek letter Δ. Thus the mouths of the Ganges form a vast breadth of waters, with intervening islands and strips of land, 200 miles in width. Into this delta the river Ganges runs laden with the rich spoils of clay, sand, vegetable matter, &c., gathered from the Himalaya Mountains, and thus those dismal-looking islands have been formed in the mouth of this river, that have become the home of tigers, crocodiles, &c.