With its immediate attendants, Mercury, Venus, Earth, Mars, etc., has been the “theme of our discourse” for the last eighteen months. Except an occasional reference to one of the planets as being located near some fixed star, or in some constellation, little has been said about the 3,391 “fixed” stars, visible to the naked eye, many of which are located on maps of the heavens, just as villages, cities, mountains, rivers and plains are located on maps of the earth; nor of the somewhere between 30,000,000 and 50,000,000 which are visible only through powerful telescopes, and whose distances from the sun are so great as to make that of Neptune appear like a little walk “across lots” to visit a neighbor. Nor is it proposed now to enter upon such an extensive subject, except so far as may be necessary to present a single thought. As we know, our sun is a bright body, whose light and heat (so great is their power) we can hardly estimate. Both these qualities render it visible to us and make us realize its presence. The other bodies, as Mars, Jupiter and the Moon are seen only by reflected light, and were they as distant as the fixed stars, would not be at all visible. These 30,000,000 to 50,000,000 stars must be suns. How many satellites has each? We do not know, for they can not be seen. Suppose each had as many as our sun. Then instead of 30,000,000 to 50,000,000 of heavenly bodies, we have within reach of the telescope from 240,000,000 to 400,000,000. How many are outside of these? No man can number them. We shall have to wait till our minds can grasp the infinite. Are these millions of bodies standing still, or are they in motion? Does our sun stand still and permit us to go around him once every year, or is he, and are we along with him, making our way through other vast multitudes and moving around some other central orb? Observation proves that the sun is only a sergeant in a great army of generals, and marches his squad in an appointed way to their assigned duties. How do we know? The records of patient watchers for centuries reveal the fact. “If we suppose the sun, attended by planets, to be moving through space, we ought to be able to detect this motion by an apparent motion of the stars in a contrary direction, as when an observer moves through a forest of trees, his own motion imparts an apparent motion to the trees in a contrary direction. All the stars would not be equally affected by such a motion of the solar system. The nearest stars would appear to have the greatest motion, but all the changes of position would appear to take place in the same direction. The stars would appear to recede from that point of the heavens _toward_ which the sun is moving, while in the opposite quarter the stars would seem to crowd more closely together.” Proceeding upon this principle, Sir William Herschel was in 1783 enabled to announce that the observed proper motion of a large portion of the stars could be accounted for on the