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190 habit of excluding light from surrounding objects by wearing a black hood.

Herschel was not content with wresting from Uranus this novel part of his story. He continued to watch the planet. Unfortunately, the same success did not crown his efforts to read its history. A great number of observations on imaginary rings and supposed moons, that were found to be stars, or not moons but probably moving, planetary bodies of the asteroid nature, demanded his attention, and deceived his hopes. It was such a tantalising pursuit, that even "the direction of a current of air alone may affect vision." At last he came to the conclusion that no ring, similar to Saturn's, girdles Uranus; but that, certainly, four additional satellites accompany him on his long journey of eighty-four years round the sun. Astronomers who came after his time failed to find these four moons, but, later still, two satellites have been added to the original two discovered by Herschel. One of the additions is suspected to belong to the four he believed he had seen circling round the planet. Of the four recognised satellites the most distant, Oberon, performs its round in 13⋅46 days, or, as Herschel found, 13 days, 11 hours, 5 minutes, 1$1⁄2$ seconds. Other information, which by careful watching he wrung from Uranus, has been verified or corrected by those who came after him; but to this unwearied observer belongs the credit of showing that the two satellites he discovered, unlike other members of the solar system, revolve in orbits nearly at right angles to the ecliptic, and that their course is retrograde, or from east to west, not direct, that is, from west to east. These were two singular and outstanding