swept right through the system of Jupiter's moons without altering their motion.
The constitution of comets, viewed in connexion with the arrangement of the solar system, strikingly illustrates the wisdom of God. Were comets not composed of such attenuated matter, the stability of the solar system would be destroyed, and life would soon be impossible on our globe. The stability depends on all the principal bodies being confined nearly to one plane; but the comets move in every possible plane, and hence if they were possessed of a planetary density, they would fatally disturb the equilibrium of the system. Were the comets restricted to the same plane in which the planets move, the danger of collision would be very great, as the long ovals in which the comets move would be constantly crossing the more circular orbits of the planets. In a crowded assembly, as long as the throng promenade in the same direction round a suite of rooms, there is no danger of coming to a lock; but if some move in an opposite direction, or attempt to cross the stream, the circulation is in danger of being brought to a dead halt. The motion of comets would interfere similarly with the regular motion of the planets, did they move in the same plane; and when we consider the thousands of comets that are constantly sweeping across the solar system, the chance of collision would be by no means inconsiderable. This danger is avoided by making the
