CONTENTS.

BOOK I.

A SKETCH OF THE SOLAR SYSTEM .

CHAPTER I.

THE SUN.

Distance of the Sun.—Its Diameter. — Its Volume. — Its Brightness.—Solar Spots. — Confined within a certain Limit. — Sun’s Axial Rotation.

— Spots visible to the naked Eye. — Scheiner. — Solar Spots and Terres-trial Temperatures.—Physical Character of the Spots. — Facul®.—

— Luculi, — Observations of Nasmyth. . . . Page 3

CHAPTER II.

THE PLANETS.

Motions of the Planets . — Features common to them all. — Kepler’s Laws .

— Explanation of the First Law. — Elements of a Planet’s Orbit.—Explanation of the Second Law. — Explanation of the Third Law.—Popular Illustration of the Extent of the Planetary System . — Bode’s Law.

— Tables of the Major Planets. — Two Groups of Planets . — Singular

Coincidences. — Planetary Conjunctions. — Conjunctions recorded inHistory.—Different Systems. . . . . .11

CHAPTER III.

VULCAN.

Le Verrier ’s Investigation of Mercury. — Narrative of the Discovery ofVulcan. — Le Verrier ’s Interview with M. Lescarbault. — ApproximateElements of Vulean. — Concluding Note. . . .28