The Nile is not the only river whose inundations are regular; the river Pegu is called the _Indian Nile_, because it overflows regularly every year; it inundates the country for more than 30 leagues from its banks; and, like the Nile, leaves an abundance of mud, which so greatly fertilizes the earth, that the pasturage is excellent for cattle, and rice grows in such great abundance, that every year a number of vessels are laden with it, without leaving a scarcity in the country.[321:A] The Niger, or what amounts to the same, the upper part of the Senegal, likewise overflows and covers all the flat country of Nigritia; it begins nearly at the same time as the Nile, and increases also for 40 days: the river de la Plata, in Brasil, also overflows every year, and at the same time as the Nile. The Ganges, the Indus, the Euphrates, and some others, overflow annually; but all rivers have not periodical overflowings, and when inundations happen it is the effect of many causes, which combine to supply a greater quantity of water than common, and, at the same time, to retard its velocity. We have before observed, that in almost all rivers the inclination of their beds diminishes towards their mouths in an almost insensible manner; but there are some whose declivity is very sudden in some places, and forms what is termed a _cataract_, which is nothing more than a fall of water, quicker than the common current of the river. The Rhine, for example, has two cataracts, the one at Bilefield, and the other near Schafhouse: the Nile has many, and among the rest two which are very violent, and fall from a great height between two mountains; the river Wologda, in Muscovy, has also two near Ladoga; the Zaire, a river of Congo, begins by a very large cataract, which falls from the top of a mountain; but the most famous is that of Niagara, in Canada, that falls from a perpendicular height of 156 feet, like a prodigious torrent, and is more than a quarter of a mile broad: the fog, or mist, which the water makes in falling, is perceived at five miles distance, and rises as high as the clouds, forming a very beautiful rainbow when the sun shines thereon. Below this cataract there are such terrible whirlpools, that nothing can be navigated thereon for six miles distance, and above the cataract the river is much narrower than it is in the upper lands[323:A]. The description given of it by _Father Charlevoix_ is as follows: "My first care, when I arrived, was to visit the most beautiful cascade that is, perhaps, in nature; but I immediately discovered that Baron la Hontain was deceived so greatly, both in its height and figure, that one might reasonably imagine he had never seen it.