RECENT COMETS—(continued)

Forms of Comets' Tails—Electrical Repulsion—Brédikhine's Three Types—Great Southern Comet—Supposed Previous Appearances—Tebbutt's Comet and the Comet of 1807—Successful Photographs—Schaeberle's Comet—Comet Wells—Sodium Blaze in Spectrum—Great Comet of 1882—Transit across the Sun—Relation to Comets of 1843 and 1880—Cometary Systems—Spectral Changes in Comet of 1882—Brooks's Comet of 1889—Swift's Comet of 1892—Origin of Comets

[CHAPTER XII]

STARS AND NEBULÆ

Stellar Chemistry—Four Orders of Stars—Their Relative Ages—Gaseous Stars—Spectroscopic Star-Catalogues—Stellar Chemistry—Hydrogen Spectrum in Stars—The Draper Catalogue—Velocities of Stars in Line of Sight—Spectroscopic Binaries—Eclipses of Algol—Catalogues of Variables—New Stars—Outbursts in Nebulæ—Nova Aurigæ—Nova Persei—Gaseous Nebulæ—Variable Nebulæ—Movements of Nebulæ—Stellar

Persei—Gaseous Nebulæ—Variable Nebulæ—Movements of Nebulæ—Stellar and Nebular Photography—Nebulæ in the Pleiades—Photographic Star-charting—Stellar Parallax—Double Stars—Stellar Photometry—Status of Nebulæ—Photographs and Drawings of the Milky Way—Star Drift

[CHAPTER XIII]

METHODS OF RESEARCH

Development of Telescopic Power—Silvered Glass Reflectors—Giant Refractors—Comparison with Reflectors—The Yerkes Telescope—Atmospheric Disturbance—The Lick Observatory—Mechanical Difficulties—The Equatoreal Coudé—The Photographic Camera—Retrospect and Conclusion

[APPENDIX]