that which considers the powers and properties of natural bodies, and their mutual actions one on another. See PHYSICS.

The business of natural philosophy, says Boerhaave, is to communicate a solid and accurate knowledge of all the bodies in being, and all the affections thereof. Nor can this science be acquired otherwise than by observing, by means of our senses, all the objects which the Author of nature hath made cognizable thereto; hence, the first and principal part of this science is to collect all the manifest and sensible appearances of things, and reduce them into a body of natural history. Now there are two ways of making such observations; the first, when we view things nearly as they happen to turn up, without any design or intervention of our own: in which way no great improvements can be expected in the art, because chance, having here the direction, only exhibits occasional or extemporary properties. The other method is, when, after a thorough acquaintance with bodies, we apply them to other bodies equally known, diligently attending to the result, and observing whether any thing new arises. See EXPERIMENTAL PHILOSOPHY.