CHAPTER III.

The house at Datchet--Housekeeping details--A devoted sister--Life at Datchet--Herschel's astronomical observations--Testing and trying "eyepieces"--The colossal telescope--Miss Herschel's accident--Removed to Slough--Constructing a forty-foot telescope--Brother and sister--Heroic self-denial--Occupations at Slough--Royal liberality--An astronomer's triumphs--About the nebulae--Investigation of the sun's constitution--The solar spots, and their influence--Physical constitution of the moon--Lunar volcanoes--Arago's explanation--Herschel's study of the planets--Satellites of Saturn--Discovery of Uranus--And of its six satellites--Study of Pigott's comet and the comet of 1811--Description of the latter--An uneventful life--Herschel's marriage--His honours--Extracts from his sister's diary--Decaying strength--Herschel removes to Bath--Last days of an astronomer--Illustration of the ruling passion--Death of Sir William Herschel--His achievements