If the observer had then specially directed his attention to one of the more humble and less brilliant of these stellar bodies, a star of the fourth class, that which is arrogantly called the Sun, all the phenomena to which the formation of the Universe is to be ascribed would have been successively fulfilled before his eyes. In fact, he would have perceived this sun, as yet in the gaseous state, and composed of moving molecules, revolving round its axis in order to accomplish its work of concentration. This motion, faithful to the laws of mechanics, would have been accelerated with the diminution of its volume; and a moment would have arrived when the centrifugal force would have overpowered the centripetal, which causes the molecules all to tend towards the centre. Another phenomenon would now have passed before the observer's eye, and the molecules situated on the plane of the equator escaping, like a stone from a sling of which the cord had suddenly snapped, would have formed around the sun sundry concentric rings resembling that of Saturn. In their turn, again, these rings of cosmical matter, excited by a rotary motion round the central mass, would have been broken up and decomposed into secondary nebulosities, that is to say, into planets. Similarly he would have observed these planets throw off one or more rings each, which became the origin of the secondary bodies which we call satellites. Thus, then, advancing from atom to molecule, from molecule to nebulous mass, from that to a principal star, from star to sun, from sun to planet, and hence to satellite, we have the whole series of transformations undergone by the heavenly bodies during the first days of the world. Now, of those attendant bodies which the sun maintains in their elliptical orbits by the great law of gravitation, some few in their turn possess satellites. Uranus has eight, Saturn eight, Jupiter four, Neptune possibly three, and the Earth _one._ This last, one of the least important of the entire solar system, we call _the Moon_; and it is she whom the daring genius of the Americans professed their intention of conquering. Illustration: THE MOON'S DISC. The moon, by her comparative proximity, and the constantly varying appearances produced by her several phases, has always occupied a considerable share of the attention of the inhabitants of the earth.