*xx

CONTENTS.

Brahe.—Halley.—Hevelius—Flamsteed.—Modern Catalogues.—Bradley.—La-caille.—Mayer.—Maskelyne.—Publication of the Histoire Celeste of Lalande.—Piazzi.—Groombridge.—Zone Catalogues of Stars.—Bessel.— Argelander.—San-tini.—Catalogue of the Astronomical Society.—Catalogues of Southern Stars.—Fallows.—Brisbane.—Johnson. —Henderson.—Standard Catalogues of Stars. —Catalogue of the British Association.—Recent Standard Catalogues . . . 506

CHAPTER XX.

Early Notions of the Telescope.—Invention of the Telescope in Holland. —Galileo constructs a Telescope.—Kepler proposes the Telescope composed of TwoConvex Lenses.—This Instrument first applied to Astronomical Purposes byGascoigne.—Telescopic Observations of Huyghens and Cassini.—ReflectingTelescope proposed by Gregory.—Newton executes a Reflecting Telescope.—Efforts of his Successors to construct these Instruments.—Invention of the Achro-matic Telescope by Dollond.—Reflecting Telescopes executed by Herschel.—Modern Improvements in the Refracting Telescope.—Improvements in the Con-struction of Reflecting Telescopes.—Lassell. — Lord Rosse .... 514

CHAPTER XXI,

Origin of Stellar Astronomy.—Physical Changes observed in the Starry Regions.

—Disappearance of Stars from the Heavens.—New Stars.— Stars of VariableLustre—Photometric Researches on the Stars. —Attempts to determine theirApparent Diameters.—Space-penetrating Power of Telescopes.—Applied toascertain the relative Distances of the Stars.—Absolute Distances of the Starsdetermined by Photometric Principles.— Parallax of the Fixed Stars.—EarlyResearches on the Subject. — Modern Researches, — Bessel.—Henderson.—Struve.—Peters.—Proper Motions of the Stars.—Motion of the Solar System inSpace.—Double Stars.—Discovery of their Physical Connexion by Sir WilliamHerschel.—Methods for determining the Elements of their Orbits.—Nebulae.—Speculations of Sir William Herschel. —Modern Researches on the Subject.—

Sir John Herschel. —The Earl of Rosse.—Early Speculations on the Milky Way .

—Theory of Wright.—Observations of Sir William Herschel. —Speculations ofthat Astronomer on the breaking up of the Milky Way.—Researches of Struveon the Distribution of the Stars in Space.—Gauges of Sir John Herschel inthe Southern Hemisphere. —Speculations of M. Struve on the Extinction ofLight in its Passage through Space ........ 537

APPENDIX.

I.—Illustrations of Planetary Perturbation .... ... 583

II.—Examination of some cases of actual Perturbation which occur in the Plane-tary System.594

III. —Reflections on certain circumstances connected with the Discovery of the

Planet Neptune ........... 603

IV. —Remarks on the Lunar Inequality termed the Evection .... 618

V.—Note respecting Horrocks.621

VI.—Account of some recent Results of Astronomical Observation . . . 622

VII.— Copy of the Observation of y Draconis which originally suggested to Bradley

his Discovery of the Aberration of Light . . . . „ . . . 624