Which of these two different theories or opinions contains the most truth remains to be found out. But respecting the arrangement of stars into streams, interesting facts have lately been discovered. We certainly see in the Solar System a tendency of heavenly bodies to travel in the same lines and in companies. Not to speak of Jupiter and his moons, or Saturn and his moons, we see it more remarkably in the hundreds of asteroids pursuing one path, the millions of meteorites whirling in herds. Would there be anything startling in the same tendency appearing on a mightier scale? Should we be greatly astonished to find streams of stars, as well as streams of planets? For such, indeed, appears to be the case. Separated by abysses of space, brother suns are plainly to be seen journeying side by side through the heavens, towards the same goal. The question of star-drift is too complex and difficult to be gone into closely in a book of this kind. One example, however, may be given. Almost everybody knows by sight the constellation of the Great Bear--the seven principal stars of which are called also Charles’s Wain, a corruption of the old Gothic _Karl Wagen_, the churl’s or peasant’s wagon. It is also called the Great Dipper. Four bright stars form a rough sort of oblong, and from one of the corners three more bright stars stretch away in a curve, representing the Bear’s tail. Many smaller stars are intermixed. [Illustration: THE GREAT BEAR.] These seven bright stars have always been bound together in men’s minds, as if they belonged to one another. But who, through the centuries past, since aught was known of the real distances of the stars from ourselves and from one another, ever supposed that any among the seven were _really_ connected together? One of these seven stars, the middle one in the tail, has a tiny companion-star, close to it, visible to the naked eye. For a good while it was uncertain whether the two were a “real double,” or only a seeming double. In time it became clear that the two did actually belong to one another. Mizar is the name of the chief star, and Alcor of the companion. Alcor is believed to be about three thousand times as far away from Mizar, as our earth from the sun. Now, if this be the width of space between those two bright points, lying seemingly so close together as almost to look to the naked eye like one, what must be the distance between the seven leading stars of the Great Bear, separated by broad sky-spaces? Who could imagine that one of these suns had aught to do with the rest?