With regard now to their more individual characteristics, the asteroids may be said to agree in one point—their diversity, not only to all the larger members of the solar family, but to one another. For they travel in orbits ranging in ellipticity all the way from such as nearly approach circles to ellipses of cometary eccentricity. They voyage, too, without regard to the dynamical plane of the system, or, what is close to it, the ecliptic; departing from the general level often 30° and, in one instance, that of the little planet dubbed W. D., by as much as 48°. This eccentricity and inclination put them in a class by themselves. It is associated and unquestionably connected mechanically with another trait which likewise distinguishes them from the planets more particularly called—their diminutive size. Only four—Vesta, Ceres, Pallas, and Juno—out of the six hundred odd now known exceed a hundred miles in diameter, and the greater number are hardly over ten or twenty miles across. Very tiny worlds indeed they would seem, could we get near enough to them to discern their forms and features. Curiously enough, reasoning on certain light changes they exhibit has enabled us to divine something of their shapes, and even character. Thus it was soon perceived that Eros fluctuated in the light he sent us, being at times much brighter than at others. In February and March, 1901, the changes were such that their maximum exceeded three times their minimum two hours and a half later. Then in May the variation vanished. More than one explanation has been put forward, but the best so far, because the most simple, is that the body is not a sphere but a jagged mass, a mountain alone in space, and that as it turns upon its axis first one corner and then another is presented to our view or throws a shade upon its neighbor. When the pole directly faces us, no great change occurs, especially if it also nearly faces the Sun. Yet even this fails to explain all its vagaries. Eros is not alone in thus exhibiting variation. Sirona, Hertha, and Tercidina have also shown periodic variability, and it is suspected in others. Indeed, it would be surprising did they not show change. For they are too small to have drawn their contents into symmetry, and so remain as they were when launched in space. Mammoth meteorites they undoubtedly are. With the asteroids we leave the inner half of the Sun’s retinue and pass to the outer. Indeed, the asteroids not only mark in place the transition bound between the two, but stamp it such mechanically. In their own persons they witness that no large body was here allowed to form. The culmination of coalition was reached in Jupiter, and that very acme of accretion prevented through a long distance any other. [Illustration: DRAWING OF JUPITER BY DR. LOWELL. APRIL 12, 1907.]