-A
thirty-foot telescope--Casting the mirror--An explosion

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

CHAPTER IV.

Birth and education of Sir John Herschel--Honours at
Cambridge--First publication--Continues his scientific studies--His
numerous literary contributions--His devotion to his father's
reputation--The forty-foot telescope--Herschel's observations on
the double and triple stars--On the refraction and polarization of
light--Catalogue of nebulae and star-clusters--Voyage to Cape
Town--Letter to Miss Herschel--Study of the southern
heavens--Return to England--Distinctions conferred upon him--His
"Familiar Lectures on Scientific Subjects"--His description of
volcanoes and earthquakes--Continual changes in the configuration
of the earth--Violent earthquakes--Phenomena of volcanic
eruptions--In Mexico--In the island of Sumbawa--Herschel's theory
of volcanic forces--His character

CHAPTER V.

Caroline Herschel's devotion to her brother William--Her grief and
solitariness at his death--Reflections on the mutability of human
things--Aunt and nephew--A parsimonious government--Miss Herschel's
gold medal--South on Sir William's discoveries--On Miss Herschel's
devotion--Her own astronomical discoveries--Her life at
Hanover--Her wonderful memory--Anecdotes of Sir John
Herschel--Correspondence between aunt and nephew--The path of
duty--Sir John's visit to Miss Herschel--Reminiscences of