In ancient times, when people lived more out-of-doors than is the habit now, they did look at them. The same primitive shepherds that, while tending their flocks at night on the hills, named the constellations according to the fanciful shapes that the unchanging stars seemed to outline, watched also the five wandering stars, more wonderful to them than any of the others. They observed how mysteriously these stars came at certain seasons and silently threaded their way across the shining heavens, and then as mysteriously disappeared. They saw them not only differing from the other stars in glory, but changing in their own brilliancy from one time to another, until, in some cases, they failed to recognize them as the same stars under varying aspects. Venus, for instance, they called Phosphorus, or Lucifer, when they saw her as a morning star, and Hesperus, or Vesper, when she shone in the evening. The sun and the moon, they noted, also moved from place to place among the fixed stars, and they called all these errant bodies planets, which means “wanderers.” These are the “seven planets” referred to in the earlier literatures and in all early books on astronomy or astrology. This is sometimes a little confusing, because, though the sun and the moon are no longer called planets, we still (omitting the earth) have seven. But Neptune and Uranus, not being visible to the naked eye, were not known to the ancients. They were discovered by means of the telescope, and that only within the last century and a half. So, owing to these comparatively new-found members of the solar family, we have yet the magic number of planets, seven. These seven are the major planets and the ones with which mainly it will be our endeavor here to promote and strengthen an acquaintance. With Uranus and Neptune the acquaintance will necessarily be less intimate than with the others, because we cannot see them in the same free way; but they are not on this account much less interesting than the others, and a little knowledge of them is pleasant family history. They simply do not live within sight. The planets that are nearer to the sun than we are, and hence lie between us and the sun, are called the inferior, or sometimes interior, planets. Those that lie outside the orbit of the earth are called the superior, or the exterior, planets. In so grouping them the earth is the dividing-point, and is not itself in either class. Mercury and Venus are the inferior planets. The superior planets are Mars, Jupiter, Saturn, Uranus, and Neptune. The distinction has importance, especially when we are discussing the planets with relation to their movements, as seen from the earth, because the planets with orbits between us and the sun (the inferior planets) have very different phases and apparent motions from those whose orbits are beyond us from the sun (the superior planets).