We really know nothing certainly about the rotation of Uranus; but there seems to be some indication that, like Jupiter and Saturn, it revolves swiftly--in perhaps ten or twelve hours, and hence has a very short day and night. The great inclination of its axis must make its seasons so abnormal, from our point of view, that it is difficult to understand what they are. Moreover, the planet is, at this stage of its development, so far from being a habitable body, for beings such as we know anything about, that the subject of its seasons seems not very important or interesting. It seems but fitting that this vapory, pale green planet should have satellites with the fairy names of Ariel, Umbriel, Titania, and Oberon. One can forgive a good many utilitarian feats in nomenclature for the sake of these charmingly appropriate names for the satellites of Uranus. Titania and Oberon were discovered in 1787 by Herschel, the discoverer of the planet. They are not very much farther from Uranus than our moon is from us, and are easily seen with a telescope. Titania, the nearer to Uranus and the larger, is probably about one thousand miles in diameter; and Oberon is not very much smaller. In 1852 Umbriel and Ariel were discovered. They are both smaller and nearer to Uranus than either of the two first discovered, and are seen with considerable difficulty, because of their proximity to the larger and brighter body of the planet. There is not, however, very much difference between any of the four in real brightness. XVI NEPTUNE It is rather curious to what extent we have a feeling of kinship with Neptune, notwithstanding he dwells forever in far-off space where we cannot expect even to have a glimpse of him without the aid of a telescope. Uranus, the other very distant planet, is so nearly within the limit of ordinary vision that we have always a hope that, by some lucky chance of situation or atmosphere, we may some day be able to see him face to face, and know for ourselves what manner of planet this is which, though a member of our own cosmic family, remains always just beyond easy exchange of glances with us; and so we in a measure keep a lookout for him that gives us a sense of his reality. With Neptune there can be no feeling of this sort to keep us with a lively interest in him, and yet he is hardly less real to us than Uranus, and we have a more intimate sense of nearness to him than we have for any fixed star. Far away as he is, the distance between us is short compared with the many trillions of miles farther that we must go to reach the nearest star, and in thinking of him we always have a sense of this. Then, however aloof he may keep himself from this cozy little bunch of planets near the sun, of which the earth is one, he is still of the same parentage with us, and his life history is part of our family history, so that we can never feel indifferent to what concerns him.