Solar
Constitution--Sir John Herschel's Trade-Wind Hypothesis--Baily's
Beads--Total Solar Eclipse of 1842--Corona and Prominences--Eclipse of
1851 52

CHAPTER IV

PLANETARY DISCOVERIES

Bode's Law--Search for a Missing Planet--Its Discovery by Piazzi--
Further Discoveries of Minor Planets--Unexplained Disturbance of
Uranus--Discovery of Neptune--Its Satellite--An Eighth Saturnian
Moon--Saturn's Dusky Ring--The Uranian System 71

CHAPTER V

COMETS

Predicted Return of Halley's Comet--Career of Olbers--Acceleration of
Encke's Comet--Biela's Comet--Its Duplication--Faye's Comet--Comet of
1811--Electrical Theory of Cometary Emanations--The Earth in a Comet's
Tail--Second Return of Halley's Comet--Great Comet of 1843--Results to
Knowledge 88

CHAPTER VI

INSTRUMENTAL ADVANCES

Two Principles of Telescopic Construction--Early Reflectors--Three
Varieties--Herschel's Specula--High Magnifying Powers--Invention of
the Achromatic Lens--Guinand's Optical Glass--The Great Rosse
Reflector--Its Disclosures--Mounting of Telescopes--Astronomical
Circles--Personal Equation 108

PART II

_RECENT PROGRESS OF ASTRONOMY_

CHAPTER I

FOUNDATION OF ASTRONOMICAL PHYSICS

Schwabe's Discovery of a Decennial Sun-spot Period--Coincidence with
Period of Magnetic Disturbance--Sun-spots and Weather--Spectrum
Analysis--Preliminary Inquiries--Fraunhofer Lines--Kirchhoff's
Principle--Anticipations--Elementary Principles of Spectrum
Analysis--Unity of Nature 125

CHAPTER II

SOLAR OBSERVATIONS AND THEORIES

Black Openings in Spots--Carrington's Observations--Rotation of the
Sun--Kirchhoff's Theory of the Solar Constitution--Faye's Views--Solar
Photography--Kew Observations--Spectroscopic Method--Cyclonic Theory
of Sun-spots--Volcanic Hypothesis--A Solar Outburst--Sun-spot
Periodicity--Planetary Influence--