[Illustration: HERCULES] One German astronomer thought he had found the center of the sun’s orbit. He believed the sun and the stars of the Milky Way to be traveling round the chief star in the Pleiades, Alcyone. This is not impossible; but it is now felt that much stronger proof will be required before the idea can be accepted. In the last chapter mention was made of star-streams as a late discovery. Though a discovery still in its infancy, it is one of no small importance. Briefly stated, the old theory as to the plan of the Milky Way was as follows: Our sun was a single star among millions of stars forming the galaxy, some comparatively near, some lying at distances past human powers of calculation, and all formed upon much the same model as to size and brightness. Where the band of milky light showed, stars were believed to extend in countless thousands to measureless distances. Where dark spaces showed, it was believed that we looked beyond the limits of our universe into black space. Stars scattered in other parts of the sky were supposed generally to be outlying members of the same great Milky Way. Many of the nebulæ and star-clusters were believed to be vast and distant gatherings of stars, like the Milky Way itself, but separated by unutterably wide reaches of space. Some of these views may yet be found to contain truth, though at the present moment a different theory is afloat. It is still thought probable that our sun is one among many millions of suns, forming a vast system or collection of stars, called by some a universe. It is also thought possible that other such mighty collections of stars may exist outside and separate from our own at immense distances. It is thought not impossible or improbable that some among the nebulæ may be such far-off galaxies of stars; though, on the other hand, it is felt that every star-cluster and nebula within reach of man’s sight may form a part of our own “universe.” According to this view of the question, the Milky Way, instead of being an enormous universe of countless suns reaching to incalculable distances, may rather be a vast and mighty star-stream, consisting of hundreds of brilliant leading suns, intermixed with thousands or even millions of lesser shining orbs. If this be the true view, the lesser suns would often be nearer than the greater suns, although more dim; and the Milky Way would not be itself a universe, though a very wonderful and beautiful portion of our universe.