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Rh cost in time and comfort, by the sacrifice of which it is purchased for mankind.

That Herschel was surprised by the brightness of the rings, the greater brightness of the shining points he saw on them, and the yellowish light of the planet, is quite clear. Whether he ever suspected a light or phosphorescence of its own in the system of Saturn, as some observers have now come to think exists, is another matter. But he was on the threshold of that discovery, if discovery it be. He entertained no such idea in 1789 when he classed all the planets "under one general definition, of bodies not luminous in themselves," though two years of farther reflection and observation may have wrought a change in a man of his clear perception and quickness. On another view developed since his day he almost anticipated recent research. He denied that the ring was subdivided by many dark lines into a series of concentric rings, "as has been represented in divers treatises of astronomy." He firmly held to only one division; but he was not far from the modern view, which represents the ring as a mighty mass of revolving satellites, kept in position by the gravity of the planet and the velocity of their rotation round him.

Herschel's memoirs on Saturn cover about one hundred and seventy pages quarto, and the plates that accompany them give a distinct idea of what he saw. By comparing letterpress and plate we may better understand the relation in which he stood to his followers in this field of research and discovery. With one of the new specula, which he ground apparently for the purpose of observing the ring of Saturn more carefully, he got views that he speaks of as "uncommonly