but one hemisphere. Does not rotation consist in turning round to us all sides in succession? This has always been a puzzle in astronomy, though only very elementary knowledge is sufficient to solve it. Even the acute metaphysician Hegel could not understand how she should rotate, and he proves, from the fundamental principles of his philosophy, that she cannot. The perplexity arises from the position we occupy. If we were without, instead of within the circle she describes in the heavens, there could be no misconception. The inhabitants of the other planets see, in succession, all parts of her circumference. In the course of twenty-eight days they can scrutinise every part of her surface. For the same reason, a person, in the centre of a circus, sees only one side of the horse galloping round the circumference, while the spectators beyond see both sides in succession.
Until lately, no conjecture could be formed of the state of things on the other side of the moon. It was regarded as one of those inscrutable mysteries which it would be folly to attempt to unveil. Human genius has triumphed over the difficulty, and has thrown a curious light on that which has hitherto been involved in deepest darkness. And, in such cases, one feels at a loss which to admire most—the wonders of God's works, or the genius with which He has endowed man to explore these works. It is to M. Hansen that the credit of the discovery is due. Mr Airy, the Astronomer-Royal, supplied him, no doubt,
