Rivers form one of the chief or-naments of the globe : while they serve not only to carry off superfluous rains and springs; but, from the great numbers and varieties of fish they contion, likewise afford a grateful food to mankind. They also greatly tend to fertilize the soils through which they flow ; and the Mud, that subsides at the bottom, as well as the weeds which vegetate on their banks, form a valuable fertilizing Manure. But, though rivers are thus beneficial to vegetation, they are easily swoln by sudden torrents, so that their banks burst, or overflow, and occasion irreparable injury. To prevent such dangerous accidents, it has been recommended to widen the courses, or passages of rivers, where they are narrow, or where the velocity of the current is otherwise obstructed: by this simple expedient, the sudden inundations of contiguous ground will be prevented ; and the numerous flocks, etc. that in low situations are apt to be carried away, will be completely secured.
River-water is much softer, and better adapted to economical purposes, than that obtained from springs : for, though all rivers originate from the latter, yet, by the rapidity of their current, and their successive exposure to the sun and air, the earthy and metallic salts which they contain, are mostly decomposed ; the acid is evolved ; and the grosser or feculent particles are in a great measure precipitated. River-water, however, is more pure and salubrious, after having passed through gravelly or sandy soils, than if it flow over muddy or clayey beds; or glide through forest, or populous villages and towns, where it becomes impregnated with numerous im-pure vegetable and animal sub-stances. In this turbid state, it is improper for domestic uses, and especially unfit for culinary sup-ply ; but, if it be suffered to subside, and be afterwards boiled and filtred, such water will become sufficiently clear and potable.- See also Alum, (vol. i. p. 37) ; Fil-tration ; and Water.