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The history of these bodies is somewhat peculiar. Besides the two brighter ones, Herschel, before 1800, thought he caught glimpses from time to time of four others, and thus it happened that for more than half a century Uranus was credited with six satellites. This was because during all that time no telescope was made which could claim superiority over Herschel's.

Then about 1845, Lassell, of England, undertook the making of reflecting telescopes, and produced his two great instruments, one of two, the other of four feet aperture. The latter he afterwards took to the Island of Malta, in order to make observations under the fine sky of the Mediterranean. Here he and his assistant entered upon a careful examination of Uranus, and reached the conclusion that none of the additional satellites supposed by Herschel had any existence. But, on the other hand, two new ones were found so near the planet that they could not have been seen by any previous observer. During the next twenty years these newly found bodies were looked for in vain with the best telescopes then in use in Europe, and some astronomers professed to doubt their existence. But in the winter of 1878 they were found with the twenty-six-inch Washington telescope, which had just been completed, and were shown to move in exact accordance with the observations of Lassell.

The most remarkable feature of these bodies is that their orbits are nearly perpendicular to the orbit of the planet. The result is that there are two opposite points of the latter orbit where that of the satellite is seen edge-