Page:Williamherschel00simegoog.djvu/189

Rh of the slightest lifting of the curtain which concealed a world of wonders from view.

As soon as his great mirror was finished, he turned it on Saturn, and "the very first moment he saw the planet, on August 28, 1789, "he was presented with a view of six of its satellites," in such a situation and so bright as rendered it impossible to mistake them or not to see them." Five of these satellites had been known for more than a century: a sixth was thus added. Constantly continuing his watch on the planet, he was rewarded, three weeks after, with discovering a seventh so close to the planet that the telescopes, previously in use, had failed to find it. Even in his great mirror "it appeared no bigger than a very small lucid point," and it lies so near the planet and its ring that "except in very fine weather, it cannot easily be seen well enough to take its place with accuracy." But he learned from experience, and taught others the lesson, that it is easier to find a small body which has been once seen, and whose place has been marked, than to detect it for the first time amid a crowd of other heavenly bodies. The heavens teach wisdom even in the littlest things, but the lessons they teach are sometimes forgotten as soon as learned. He found also that the time of a sidereal revolution round the planet is 22 hours, 37 minutes, 22 seconds. Both it and the other moon he discovered revolve so near and so parallel to the ring, that he had "repeatedly seen