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surface. If we supposed animals to walk about on the moon, it is difficult to imagine what they could eat. Our general conclusion must be that there is no life on the moon subject to the laws which govern life on the surface of this earth.

The total absence of air and water results in a state of things on the moon such as we never experience on the earth. So far as can be ascertained by the most careful examination, not the slightest change ever takes place on its surface. A stone lying on the surface of the earth is continually attacked by the weather and in the course of years is gradually disintegrated or washed away by the wind and water. But there is no weather on the moon, and a stone lying on its surface might rest there for unknown ages undisturbed by any cause whatever. The lunar surface is heated up when the sun shines on it and it cools off when the sun has set. Except for these changes of temperature there is absolutely nothing going on over the whole surface of the moon, so far as we can see. A world which has no weather and on which nothing ever happens—such is the moon.

The rotation of the moon on its axis is a subject on which some are frequently so perplexed that we shall explain it. Anyone who has carefully examined this body knows that it always presents the same face to us. This shows that it rotates on its axis in the same time that it revolves around the earth. An idea frequently entertained is that this shows that it does not rotate at all,