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 than that which forms the nebula now under consideration. Such globes are, doubtless, undergoing condensation, and may be regarded as incipient worlds.

Our fellow-planets like the earth are guided and held in their ever-circling way by the attraction of the sun, while they are also illuminated by the light which he pours forth with such liberality, and warmed with the rays of heat which he sends them. The sun does not, indeed, confer these benefits in an equal degree on all the members of his family; those which are nearer to him get much, perhaps too much according to our notions, of his heat, while those like Uranus or Neptune, which lie on the outskirts of the system, get little, perhaps too little, of those particular benefits which he dispenses. This world of ours thus occupies a somewhat intermediate position. The structure of the human body would have to be considerably modified if we were to find a congenial residence either so near the sun as Mercury or so far from him as Neptune. As we live on this earth in the temperate regions, and suffer neither from the fearful heat at the equator nor from the horrors of the frozen poles, so too does our entire world enjoy what we may describe as a temperate situation in the series of bodies belonging to the solar system.

In other respects, too, our position is an intermediate one. There are some planets, such as Mars and Mercury, which are very much smaller than our earth. There are other planets, such as Jupiter and Saturn, which are enormously greater than the earth; and there is Venus, our beautiful neighbour, which is almost exactly the same size. Considering that this earth may be taken as an average specimen of the worlds which form the sun's