Man Becomes Acquainted With the Laws of the Universe

Rational mechanics soon became a vast and profound science. The true laws of the collision of bodies, respecting which Descartes was deceived, were at length known.

Huyghens discovered the laws of circular motions; and at the same time he gives a method of determining the radius of curvature for every point of a given curve. By uniting both theories, Newton invented the theory of curve-lined motions, and applied it to those laws according to which Kepler had discovered that the planets describe their elliptical orbits.

A planet, supposed to be projected into space at a given instant, with a given velocity and direction, will describe round the sun an ellipsis, by virtue of a force directed to that star, and proportional to the inverse ratio of the squares of the distances. The same force retains the satellites in their orbits round the primary planets: it pervades the whole system of heavenly bodies, and acts reciprocally between all their component parts.

The regularity of the planetary ellipses is disturbed, and the calculation precisely explains the very slightest degrees of these perturbations. It is equally applicable to the comets, and determines their orbits with such precision, as to foretel their return. The peculiar motion observed in the axes of rotation of the earth and the moon, affords additional proof of the existence of this universal force. Lastly, it is the cause of the weight of terrestrial bodies, in which effect it appears to be invariable, because we have no means of observing its action at distances from the centre, which are sufficiently remote from each other.

Thus we see man has at last become acquainted, for the first time, with one of the physical laws of the universe. Hitherto it stands unparalleled, as does the glory of him who discovered it.

When we learned and understood the motions of bodies in space.