new asteroids being found. We now know that this was because the rest were all much smaller, and for such nobody looked. It was not till 1845 that Hencke, an ex-postmaster of Driessen in Prussia, after fifteen years of search detected another, Astræa, of the 11th magnitude. After this discoveries of them came on apace, until now more than six hundred are known, and their real number seems to be legion. But those discovered are smaller each year on the average, showing that the larger have already been found. Their orbits are such that they cannot possibly ever have all formed part of a pristine whole. The idea, not the body, was exploded. For they are now recognized as having always been much as they are to-day.
They prove to be thickest at nearly the point where Bode's law required, the spot where Ceres and Pallas were found. The mean of their distances is less, being 2.65 instead of 2.8 astronomical units, probably simply because the nearer ones are easier discovered. The fact that they are clustered most thickly just inside 2.8 astronomical units implies that there of all points within the space between Mars and Jupiter a planet would have formed if it could. A definite reason exists for its failure to do so—Jupiter's disturbing presence. Throughout this whole region Jupiter's influence is great; so great that his scattering effect upon the particles exceeds their own tendency to come
