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We have shown how this comparatively small family of bodies, on one of which we dwell, forms as it were a little colony by itself. Small though it be when compared with the whole universe as a standard, it is for us the most important part of the universe. Before proceeding to a description of its various bodies in detail we must take a general view to show of what kind of bodies it is formed and how it is made up.

First of all we have the sun, the great shining central body, shedding warmth and light on all the others and keeping the whole system together by virtue of its powerful attraction.

Next we have the planets, which revolve round the sun in their regular orbits, and of which our earth is one. The word planet means wanderer, a term applied in ancient times because these bodies, instead of keeping their places among the fixed stars, seemed to wander about among them. The planets are divided into two quite distinct classes, termed major and minor.

The major planets are eight in number and are, next to the sun, the largest bodies of the system. For the most part their distances from the sun are arranged in a close approach to a certain regular order, ranging from nearly forty millions of miles in the case of Mercury,