Four of them can easily be seen with quite a small telescope, and were seen by Galileo with the first telescope ever turned to the skies. The other four are very faint and were not discovered until recently. Just as Jupiter is so much bigger than our Earth, so is his system of satellites on a much grander scale than ours. Our model of the little Earth has our single Moon at a distance of 2 feet; but though one or two of Jupiter's satellites are about as near as this, others would be outside this lecture hall on the same scale, and one of them half-way down Albemarle Street!
Saturn has also a number of separate satellites besides the great crowd of little tiny ones which make up the ring. We know of nine or ten already (the tenth has been announced, but has not yet been satisfactorily identified), and they also are scattered to great distances from the planet himself.
If we chose to land on one of these satellites we should be liable to an experience which is quite unfamiliar on our Earth—that of a long eclipse of the Sun, when day would be turned into night. It is just possible to have a total eclipse of the Sun even on our Earth, but only for a few minutes. The Moon is not large enough to cover up the Sun for very long. Perhaps you have read an exciting book called King Solomon's Mines? When Sir Rider Haggard first wrote it, he introduced a total eclipse of the Sun which was quite impossibly long; it lasted (if I reremember rightly) several hours, and the darkness was so great that the people could only grope their way about, being quite unable to see "their hands before their faces." Somebody must have told him this was all quite a mistake, because in later editions
