Chapter LX: Appendix: Table I (1)

STARS WITH VARIABLE SPECTRA ┌───────────────┬────┬───────────────┬────────────────────────────────┐ │ Name of Star. │Mag.│Position, 1900.│ Remarks. │ ├───────────────┼────┼──┬──┬─────────┼────────────────────────────────┤ │ „ │ „ │R.│A.│ Dec. │ „ │ ├───────────────┼────┼──┼──┼─────┬───┼────────────────────────────────┤ │ │ │h.│m.│ │ │ │ │γ Cassiopeiæ │ 2·3│ 0│51│+ 60°│10′│Hα usually brilliant; at times │ │ │ │ │ │ │ │ invisible. D_{3} │ │ │ │ │ │ │ │ intermittently bright. Further│ │ │ │ │ │ │ │ variations apparent. │ │8 Schjellerup │ 7·2│ 1│12│+ 47°│ 9′│Spectrum continuous, 14th │ │ │ │ │ │ │ │ November 1887; fluted, 6th │ │ │ │ │ │ │ │ October 1891. │ │ο Ceti │var.│ 2│14│− 3°│26′│Hγ and Ηδ triple, 29th August; │ │ │ │ │ │ │ │ single, 6th November 1898. │ │ │ │ │ │ │ │ Iron (?) line at λ 4308, dark │ │ │ │ │ │ │ │ at maxima of 1896 and 1897, │ │ │ │ │ │ │ │ bright in 1898. │ │ψ Persei │ 4·2│ 3│29│+ 47°│52′│Bright Ηβ shifts capriciously │ │ │ │ │ │ │ │ from one to the other side of │ │ │ │ │ │ │ │ a broad absorption-band, on │ │ │ │ │ │ │ │ which it is normally central │ │ │ │ │ │ │ │ (A. C. Maury). │ │11 Monocerotis │ 4·7│ 6│24│ − 6°│58′│Bright Ηβ less refrangible in │ │ │ │ │ │ │ │ 1888–90, more refrangible in │ │ │ │ │ │ │ │ 1891–2 than dark Ηβ. │ │A.G.C. 9181 │ 5·4│ 7│10│− 26°│10′│Ηβ and Hγ vary from dark to │ │ │ │ │ │ │ │ bright, not always in concert │ │ │ │ │ │ │ │ (A. J. Cannon). │ │J Velorum │ 4·4│10│17│− 55°│33′│Ηβ and Hγ intermittently bright │ │ │ │ │ │ │ │ (A. J. Cannon). │ │A.G.C. 14,686 │ 7·0│10│40│− 59°│ 1′│H · lines alternately bright and│ │ │ │ │ │ │ │ dark (_Harvard Circular_, No. │ │ │ │ │ │ │ │ 32). │ │η Centauri │ 2·5│14│29│− 41°│43′│Composite spectrum, subject to │ │ │ │ │ │ │ │ intricate changes, partly │ │ │ │ │ │ │ │ explicable relative │ │ │ │ │ │ │ │ motion-shifts of bright and │ │ │ │ │ │ │ │ dark Ηβ (A. J. Cannon). │ │κ′ Apodis │ 5·6│15│21│− 73°│ 2′│Ηβ variably bright (A. J. │ │ │ │ │ │ │ │ Cannon). │ │R Coronæ │var.│15│44│+ 28°│28′│Spectrum at times continuous, at│ │ │ │ │ │ │ │ times banded. Bright lines │ │ │ │ │ │ │ │ occasionally visible. │ │214 Schjellerup│ 7·0│18│28│− 5°│13′│Spectrum third type, 1889; │ │ │ │ │ │ │ │ second type, 1892. │ │R Scuti │var.│18│42│− 5°│49′│Type III.; bands effaced at │ │ │ │ │ │ │ │ maxima. Unidentified bright │ │ │ │ │ │ │ │ lines recorded by Espin in │ │ │ │ │ │ │ │ 1890. │ │β Lyræ │var.│18│46│+ 33°│15′│Composite spectra with variable │ │ │ │ │ │ │ │ and shifting bright lines. │ │υ Sagitarii │ 4·7│19│16│− 16°│ 8′│Hβ variably bright (A. C. │ │ │ │ │ │ │ │ Maury). │ │ε Capricorni │ 4·5│21│36│− 19°│54′│Composite helium spectrum. │ │ │ │ │ │ │ │ Changes possibly explicable by│ │ │ │ │ │ │ │ motion-shifts of two │ │ │ │ │ │ │ │ dissimilar sets of dark lines │ │ │ │ │ │ │ │ (A. J. Cannon). │ └───────────────┴────┴──┴──┴─────┴───┴────────────────────────────────┘

TABLE II

LIST OF SPECTROSCOPIC BINARIES ┌─────────────┬───────┬─────────┬────────┬──────┬─────────────────────┐ │Name of Star.│ R. A. │ Dec. │ Mag. │Period│ Remarks. │ │ │ 1900. │ 1900. │ │ in │ │ │ │ │ │ │Days. │ │ ├─────────────┼───────┼─────────┼────────┼──────┼─────────────────────┤ │ │h. m.│ │ │ │ │ │η Andromedæ │ 0 52│+ 22° 52′│ 4·6│ │Variable radial │ │ │ │ │ │ │ motion discovered │ │ │ │ │ │ │ by Campbell, 1900. │ │ │ │ │ │ │ Spectrum of │ │ │ │ │ │ │ companion faintly │ │ │ │ │ │ │ visible. Solar │ │ │ │ │ │ │ type. │ │Polaris │ 1 22│+ 88° 46′│ 2·1│ 3·97│Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Spectrum early │ │ │ │ │ │ │ solar. Companion │ │ │ │ │ │ │ dark. Further │ │ │ │ │ │ │ disturbance │ │ │ │ │ │ │ indicated. │ │φ Persei │ 1 37·4│+ 50° 11′│ 4·2│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell in 1902. │ │ │ │ │ │ │ Bright-line helium │ │ │ │ │ │ │ spectrum. │ │ξ Piscium │ 1 48│+ 2° 42′│ 4·7│ │Variable velocity │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Campbell, 1900. │ │ │ │ │ │ │ Companion sensibly │ │ │ │ │ │ │ dark. │ │ξ_{1} Ceti │ 2 8│+ 8° 23′│ 4·4│ │Variable velocity │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Campbell, October │ │ │ │ │ │ │ 1900. Companion │ │ │ │ │ │ │ dark. │ │12 Persei │ 2 36│+ 39° 46′│ 4·9│ │Discovered by │ │ │ │ │ │ │ Campbell, January │ │ │ │ │ │ │ 1900. Two similar │ │ │ │ │ │ │ spectra visible at │ │ │ │ │ │ │ elongations. │ │τ Persei │ 2 47│+ 52° 22′│ 4·0│ │Radial velocity found│ │ │ │ │ │ │ variable by │ │ │ │ │ │ │ Campbell in October│ │ │ │ │ │ │ 1900. Spectrum │ │ │ │ │ │ │ previously observed│ │ │ │ │ │ │ as composite by A. │ │ │ │ │ │ │ C. Maury. Solar │ │ │ │ │ │ │ type. │ │β Persei │ 3 2│+ 40° 34′│ var.│ 2·87│Alternations of │ │ (Algol) │ │ │ │ │ approach and │ │ │ │ │ │ │ recession │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Vogel, 1889. │ │ │ │ │ │ │ Companion obscure. │ │ο Persei │ 3 38│ +31° 58′│ 4·0│ │Found by W. S. Adams │ │ │ │ │ │ │ in 1902 to vary in │ │ │ │ │ │ │ radial velocity to │ │ │ │ │ │ │ the extent of 251 │ │ │ │ │ │ │ kil. Single │ │ │ │ │ │ │ spectrum of helium │ │ │ │ │ │ │ type. │ │λ Tauri │ 3 55│ +12° 12′│ var.│ 3·95│Changes of velocity │ │ │ │ │ │ │ measured by │ │ │ │ │ │ │ Bélopolsky, 1897. │ │ │ │ │ │ │ Spectrum │ │ │ │ │ │ │ periodically │ │ │ │ │ │ │ double. Helium │ │ │ │ │ │ │ type. │ │α Aurigæ │ 5 9│ +45° 54′│ 0·2│ 104│Discovered by │ │ (Capella) │ │ │ │ │ Campbell and │ │ │ │ │ │ │ Newall, 1899. │ │ │ │ │ │ │ Spectrum composite.│ │η Orionis │ 5 19·4│ −2° 29′│ 3·5│ │Variable velocity │ │ │ │ │ │ │ detected with the │ │ │ │ │ │ │ Bruce spectrograph │ │ │ │ │ │ │ in 1901 by W. S. │ │ │ │ │ │ │ Adams and E. B. │ │ │ │ │ │ │ Frost. │ │δ Orionis │ 5 27│ −0° 22′│ 2·4│ 1·92│Discovered by │ │ │ │ │ │ │ Deslandres, 1900. │ │ │ │ │ │ │ Spectrum of helium │ │ │ │ │ │ │ type. Companion │ │ │ │ │ │ │ obscure. │ │β Aurigæ │ 5 52│ +44° 56′│ 2·1│ 3·98│Discovered by Miss │ │ │ │ │ │ │ Maury in 1889. │ │ │ │ │ │ │ Spectrum first │ │ │ │ │ │ │ type; doubled │ │ │ │ │ │ │ periodically. │ │η Geminorum │ 6 8·8│ +22° 33′│ 3·2–4·2│ │Variable velocity │ │ │ │ │(period,│ │ detected by │ │ │ │ │ 231^d)│ │ Campbell in 1902. │ │ │ │ │ │ │ Close visual │ │ │ │ │ │ │ companion │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Burnham, 1881. Slow│ │ │ │ │ │ │ revolution │ │ │ │ │ │ │ indicated. The │ │ │ │ │ │ │ variable shows a │ │ │ │ │ │ │ fluted spectrum. │ │ζ Geminorum │ 6 58│ +20° 43′│ var.│ 10·15│Discovered by │ │ │ │ │ │ │ Bélopolsky, 1898. │ │ │ │ │ │ │ Subordinate period │ │ │ │ │ │ │ of 3·38^d detected │ │ │ │ │ │ │ by Campbell. │ │ │ │ │ │ │ Spectrum solar │ │ │ │ │ │ │ type. Companion │ │ │ │ │ │ │ dark. │ │γ Canis │ 7 23│ +9° 8′│ 4·6│ │Discovered by │ │ Minoris │ │ │ │ │ Campbell in 1902 to│ │ │ │ │ │ │ vary in velocity to│ │ │ │ │ │ │ the extent of 8 │ │ │ │ │ │ │ miles per second. │ │α′ Geminorum │ 7 28│ +32° 7′│ 2·0│ 2·95│Discovered by │ │ (Castor) │ │ │ │ │ Bélopolsky, 1896. │ │ │ │ │ │ │ First type │ │ │ │ │ │ │ spectrum. Companion│ │ │ │ │ │ │ obscure. Line of │ │ │ │ │ │ │ apsides found to │ │ │ │ │ │ │ revolve in 2100^d. │ │V Puppis │ 7 55│ −48° 58′│ var.│ 1·45│Periodical doubling │ │ │ │ │ │ │ of lines detected │ │ │ │ │ │ │ by Pickering from │ │ │ │ │ │ │ Arequipa plates in │ │ │ │ │ │ │ 1896. A. W. Roberts│ │ │ │ │ │ │ finds components to│ │ │ │ │ │ │ revolve in contact.│ │ │ │ │ │ │ Helium spectrum. │ │ε Hydræ │ 8 42│ +6° 48′│ 3·6│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, December │ │ │ │ │ │ │ 1900. Solar │ │ │ │ │ │ │ spectrum. │ │ο Leonis │ 9 36│ +10° 21′│ 3·8│ 14·5│Discovered by │ │ │ │ │ │ │ Campbell, 1898. │ │ │ │ │ │ │ Spectrum previously│ │ │ │ │ │ │ noticed by Miss │ │ │ │ │ │ │ Maury to be │ │ │ │ │ │ │ compounded of two │ │ │ │ │ │ │ varieties of the │ │ │ │ │ │ │ Sirian type. │ │ξ Ursæ │11 13│ +32° 6′│ 3·8│ │Principal component │ │ Majoris │ │ │ │ │ of visual binary │ │ │ │ │ │ │ found by Wright in │ │ │ │ │ │ │ 1900 to be │ │ │ │ │ │ │ spectroscopically │ │ │ │ │ │ │ double. Spectrum │ │ │ │ │ │ │ solar. │ │93 Leonis │11 43│ +20° 46′│ 4·6│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1900. │ │ξ Ursæ │13 20│ +55° 27′│ 2·4│ 20·6│Discovered by │ │ Majoris │ │ │ │ │ Pickering, 1889. │ │ │ │ │ │ │ Period fixed by │ │ │ │ │ │ │ Vogel, 1901. │ │ │ │ │ │ │ Spectrum advanced │ │ │ │ │ │ │ helium type. │ │ │ │ │ │ │ Components equally │ │ │ │ │ │ │ bright. │ │α Virginis │13 20│ −10° 38′│ 1·2│ 4·0│Discovered by Vogel, │ │ │ │ │ │ │ 1890. Companion │ │ │ │ │ │ │ faintly luminous. │ │ │ │ │ │ │ Helium spectrum. │ │ζ Centuari │13 49│ −46° 47′│ 2·8│ 8·02│Discovered by Mrs. │ │ │ │ │ │ │ Fleming, 1899. │ │ │ │ │ │ │ Components │ │ │ │ │ │ │ unequally bright. │ │ │ │ │ │ │ Spectrum helium │ │ │ │ │ │ │ type. │ │d Boötis │14 6│ +25° 34′│ 4·8│ │Variable velocity │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Wright, April 1900.│ │β Lupi │14 52│ −42° 44′│ 2·7│ │Discovered by Mrs. │ │ │ │ │ │ │ Fleming, 1897. │ │ │ │ │ │ │ Components equally │ │ │ │ │ │ │ luminous. Helium │ │ │ │ │ │ │ spectrum. │ │δ Libræ │14 56│ −8° 8′│ var.│ 2·33│Variable velocity │ │ │ │ │ │ │ detected by Adams, │ │ │ │ │ │ │ 1902. Spectrum │ │ │ │ │ │ │ advanced helium │ │ │ │ │ │ │ type. │ │ε Libræ │15 19│ −9° 57′│ 5·2│ 90+│Discovered by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Solar spectrum. │ │ │ │ │ │ │ Companion obscure. │ │π Scorpii │15 53│ −25° 49′│ 3·1│ 1·57│Discovered by Miss │ │ │ │ │ │ │ Cannon, 1899. │ │ │ │ │ │ │ Helium spectrum. │ │ │ │ │ │ │ Components │ │ │ │ │ │ │ unequally bright. │ │Θ Draconis │16 0│ +58° 50′│ 4·2│ 9│Discovered by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Spectrum solar │ │ │ │ │ │ │ type. Companion │ │ │ │ │ │ │ obscure. │ │β Herculis │16 26│ +21° 42′│ 2·8│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Companion dark. │ │ │ │ │ │ │ Arcturian spectrum.│ │μ_{1} Scorpii│16 45│ −37° 53′│ 3·3│ 1·45│Discovered by Bailey,│ │ │ │ │ │ │ 1896. Components │ │ │ │ │ │ │ unequally bright, │ │ │ │ │ │ │ perhaps variable. │ │ │ │ │ │ │ Spectra of helium │ │ │ │ │ │ │ type. │ │_h_ Draconis │16 55│ +65° 17′│ 4·7│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Early solar │ │ │ │ │ │ │ spectrum. Companion│ │ │ │ │ │ │ dark. │ │ε Ursæ │16 56│ +82° 12′│ 4·5│ │Discovered by │ │ Minoris │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Spectrum solar. │ │ │ │ │ │ │ Companion obscure. │ │ω Draconis │17 38│ +68° 48′│ 4·9│ │Discovered by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Spectrum solar. │ │ │ │ │ │ │ Companion obscure. │ │χ Draconis │18 23│ +72° 42′│ 3·7│ 282│Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1898. │ │ │ │ │ │ │ Period computed by │ │ │ │ │ │ │ Wright. Early solar│ │ │ │ │ │ │ spectrum. Companion│ │ │ │ │ │ │ dark. │ │2 Scuti │18 37│ −9° 9′│ 4·8│ │Variable velocity │ │ │ │ │ │ │ detected by Wright,│ │ │ │ │ │ │ 1900. Companion │ │ │ │ │ │ │ dark. │ │β Scuti │18 42│ −4° 51′│ 4·4│ │Variable velocity │ │ │ │ │ │ │ detected by Wright,│ │ │ │ │ │ │ 1900. Companion │ │ │ │ │ │ │ obscure. │ │β Lyræ │18 46│ +33° 15′│ var.│ 12·91│Binary character │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Pickering, 1891. │ │ │ │ │ │ │ Bright-line helium │ │ │ │ │ │ │ spectrum. │ │ │ │ │ │ │ Components │ │ │ │ │ │ │ luminous. │ │113 Herculis │18 50│ +22° 32′│ 4·6│ │Variable velocity │ │ │ │ │ │ │ detected by Wright,│ │ │ │ │ │ │ July 1900. │ │ │ │ │ │ │ Companion obscure. │ │υ Sagittarii │19 16│ −16° 8′│ 4·7│ │Variable velocity │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Spectrum noted as │ │ │ │ │ │ │ composite by Miss │ │ │ │ │ │ │ Maury. Of helium │ │ │ │ │ │ │ type with bright │ │ │ │ │ │ │ lines. │ │η Aquilæ │19 47│ +0° 45′│ var.│ 7·18│Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Bélopolsky, 1895. │ │ │ │ │ │ │ Spectrum solar. │ │ │ │ │ │ │ Companion dark. │ │ο_{1} Cygni │20 10│ +46° 26′│ 3·8│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, July │ │ │ │ │ │ │ 1900. Spectrum │ │ │ │ │ │ │ previously │ │ │ │ │ │ │ described by Miss │ │ │ │ │ │ │ Maury as including │ │ │ │ │ │ │ Sirian and solar │ │ │ │ │ │ │ ingredients. │ │β Capricorni │20 15│ −15° 5′│ 3·4│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Spectrum previously│ │ │ │ │ │ │ perceived by Miss │ │ │ │ │ │ │ Maury to be of │ │ │ │ │ │ │ Sirian and solar │ │ │ │ │ │ │ composition. │ │α Equulei │21 11│ +4° 50′│ 4·1│ │Variable velocity to │ │ │ │ │ │ │ the extent of 15 │ │ │ │ │ │ │ miles a second │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Campbell in 1902. │ │ │ │ │ │ │ Miss Maury had │ │ │ │ │ │ │ recorded a │ │ │ │ │ │ │ composite spectrum,│ │ │ │ │ │ │ solar and Sirian. │ │κ Pegasi │21 40│ +25° 11′│ 4·2│ 6±│Smaller member of the│ │ │ │ │ │ │ visual binary found│ │ │ │ │ │ │ by Campbell in 1900│ │ │ │ │ │ │ to be in rapid │ │ │ │ │ │ │ revolution round a │ │ │ │ │ │ │ dark companion. │ │ │ │ │ │ │ Sirian spectrum. │ │ι Pegasi │22 2│ +24° 51′│ 4·0│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1898. │ │ │ │ │ │ │ Spectrum of Procyon│ │ │ │ │ │ │ class. Companion │ │ │ │ │ │ │ obscure. │ │δ Cephei │22 25│ +57° 54′│ var.│ 5·37│Binary character │ │ │ │ │ │ │ discovered by │ │ │ │ │ │ │ Bélopolsky, 1894. │ │ │ │ │ │ │ Solar spectrum. │ │ │ │ │ │ │ Companion dark. │ │η Pegasi │22 38│ +29° 42′│ 3·1│ 818·0│Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1898. │ │ │ │ │ │ │ Spectrum solar. │ │ │ │ │ │ │ Companion dark. │ │ο Andromedæ │22 57│ +41° 47′│ 3·8│ │Variable velocity │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1902. │ │ │ │ │ │ │ Composite │ │ │ │ │ │ │ spectrum—Sirian and│ │ │ │ │ │ │ Orion—recorded by │ │ │ │ │ │ │ Miss Maury. │ │π Cephei │23 5│ +74° 1′│ 4·5│ │Variable motion │ │ │ │ 5 │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1900. │ │ │ │ │ │ │ Companion dark. │ │λ Andromedæ │23 33│ +45° 56′│ 4·0│ 19·2│Variable motion │ │ │ │ │ │ │ detected by │ │ │ │ │ │ │ Campbell, 1899. │ │ │ │ │ │ │ Spectrum Arcturian.│ │ │ │ │ │ │ Companion dark. │ └─────────────┴───────┴─────────┴────────┴──────┴─────────────────────┘

INDEX

Abbe, structures in solar corona, 129

Abbot, measurements of coronal heat, 131, 138 Abney, Sir William, photography of infra-red solar spectrum, 25; theoretical effects of rotation in stellar spectra, 280

Airy, the solar sierra, 102

Alcyone, a helium star, 194;
red hydrogen line bright in spectrum, 229, 230, 279, 284;
coupled with a dark line, 420;
radiative power, 415;
attendant nebulosities, 418

Aldebaran, spectral character, 183, 207;
parallax and luminosity, 208;
a perspective member of the Hyades, 412

Alexander, contour of Owl nebula, 473;
bi-annular nebula, 490

Algol, density, 192, 303;
spectrum, 194, 197, 283;
supposed colour-change, 256;
probable velocity of rotation, 283;
eclipses, 302;
system, 303–306;
dark satellite, 302, 401

Al-Sûfi, redness of Algol, 256;
magnitude of Θ Eridani, 373

Altair, peculiar spectrum, 280;
rotational hypothesis, 281;
inapplicability, 282, 283;
incipient bright lines, 284

Ambronn, triangulation of the Pleiades, 421

Ames, spectral researches, 34, 53

Anderson, variability of T Andromedæ, 358;
fading of Θ Eridani, 373;
discoveries of Nova Aurigæ, 375;
and of Nova Persei, 388

Andromeda nebula, temporary star in, 385;
spectrum, 439, 449;
spirality, 440;
attendants, 441, 457;
constitution, 450

Ångström, C. J., recognition of hydrogen-absorption in the sun, 52

Ångström, K., bands of telluric absorption traced to carbon dioxide,
24;
atmospheric heat-stoppage, 65

Annular nebulæ, relation to planetaries, 469, 472;
examples, 484–493;
nuclear stars, 486, 489, 490, 493;
spectra, 488, 491;
structures of intermediate character, 490, 493;
desirability of further research, 494

Antares, shows a typical fluted spectrum, 179, 184, 210, 211;
adjacent nebula, 190, 514;
actual brightness, 213, 214

Antarian stars, 179, 184, 209–214;
development, 272, 276, 277, 278;
probable massiveness, 275

Antoniadi, nucleus of ring-nebula in Cygnus, 489

Aquilæ, η, light-change, 321;
orbit, 322, 323

Archenhold, photograph of a nebula in Perseus, 513

Arcturus, spectrum, 182, 183, 205, 207;
luminous power, 205

Argelander, period of ζ Geminorum, 328;
light-curve of β Lyræ, 337;
inequalities of Mira, 348, 349;
of χ Cygni, 352;
period of R Lyræ, 368;
disappearances of R Coronæ, 371

Argon, non-apparent in the sun, 28, 30

Argûs, γ, bright-line spectrum, 187, 238, 239

Astrophysics, prevision of, 1;
development, 2–5;
widening of scope, 5–8;
character and future, 9, 10

Atlas, a suspected binary star, 421

Aurigæ, β, a spectroscopic binary, 291

Auroræ, analogy with solar corona, 139;
abnormal scarcity, 156

Auwers, detection of a nebulous star, 471;
observation of Hind’s variable nebula, 523

Bacon, prevision of astrophysics, 1, 2

Bacon, Miss, coronal photographs, 135

Bailey, double spectrum of μ Scorpii, 292;
of V Puppis, 334;
discovery of cluster-variables, 336, 434;
their mode of light-change, 435, 437;
spectrograph of Nova Normæ, 382;
counts of the Pleiades, 416;
encircling nebulosity, 419;
photograph of ω Centauri, 431

Baillaud and Bourget, photograph of a nondescript nebula, 519

Ball, Sir Robert, parallax of 1618 Groombridge, 206

Balmer, law of series, 52–54

Barnard, photographic investigation of the Milky Way, 7, 539, 540, 544;
observations of cluster-variables, 177, 434, 435;
photographs of a nebula in Monoceros, 190, 425, 426;
of galactic nebulosities, 205, 513, 514;
of Messier 11, 411;
of nebulosities encircling the Pleiades, 418, 420;
of Messier 8, 424;
of fan nebulæ, 447;
of a nebular group, 458;
of nebulous stars, 462, 463, 464, 465, 466;
of nebulous formation in Orion, 497;
detection of stars in trapezium, 230, 495;
observation of Τ Tauri, 372, 373;
nebulous and non-nebulous clusters, 412;
visual discoveries of nebulæ, 417, 474, 487;
portrait-lens photography, 423;
globular clusters non-nebulous, 433;
Stephan’s star non-nebulous, 467;
central star in Lyra nebula, 487;
structure of an annular nebula, 493;
notices of variable nebulæ, 523, 524, 525, 526, 527;
composition of the Milky Way, 542

Baxendell, eclipses of λ Tauri, 307;
minima of S Ursæ Majoris, 353;
periodicity of R Lyræ, 368

Bayer, star-maps of 1603, 371

Becker, telluric spectrum, 23

Bell, nebulous formation round Nova Persei, 395

Bellatrix, a typical helium star, 191

Bélopolsky, solar eclipse of 1896, 128;
correspondence of coronal changes with surface-phenomena, 129;
rotation of faculæ, 145;
of the corona, 147;
nitrogen lines in P Cygni, 235;
system of Castor, 293, 294;
radial motion of λ Tauri, 307;
of δ Cephei, 320;
of ζ Geminorum, 328;
system of β Lyræ, 339, 340

Berberich, effects on Encke’s comet of solar periodicity, 158

Bessel, dark stars, 400

Betelgeux, spectral affinities, 183, 210, 211;
real magnitude, 213, 214;
irregular variability, 369

Bevis, discovery of Crab nebula, 517

Bigelow, magnetic theory of corona, 138, 139;
solar rotation, 143;
modes of propagation of solar energy, 157

Bigourdan, observation of a variable nebula, 526

Birmingham, colours of stars, 257, 258

Boguslawski, record of a variable nebula, 528

Boisbaudrin, discovery of gallium, 28

Bolometer, applied to investigate infra-red solar spectrum, 22;
to measure coronal heat, 131

Boltzmann, law of radiation, 64

Bond, measurement of stars in Orion nebula, 504

Bouguer, darkening of the sun’s disc, 70

Boys, invention of radio-micrometer, 64

Bradley, measures of β Cygni, 264;
of Castor, 293

Brown, Miss, drawing of a spot-group, 79

Burckhalter, graduated coronal photographs, 133

Burnham, division of σ Orionis, 261;
of η Geminorum, 267;
observations of T Tauri, 372;
of Barnard’s Merope nebula, 417;
of double and triple nebulæ, 453, 458;
of nebulous stars, 461, 463, 464, 466, 467;
of planetary nebulæ, 474, 475, 480, 483;
of stellar nebulæ, 481;
of nuclear stars in annular nebulæ, 487, 489, 490;
of variable nebulæ, 523, 526, 528

Burns, magnitudes of galactic stars, 542

Buss, helium absorption in sun-spot spectra, 94

Calcium, isolation of its violet ray for solar photography, 18, 99,
101;
a constituent of the sun, 27;
emission lines in sun-spots, 95;
in faculæ, 100, 101;
in prominences, 110, 114, 115, 120;
in stars, 232;
absence from corona, 136;
absorption by in stellar spectra, 182, 185, 191, 192, 193, 200, 201,
203, 207, 209, 212, 225, 226, 390

Calvert, drawing of the Pleiades nebulosities, 419

Campbell, coronal spectrographs, 131, 132, 136;
bright and dark spectral series, 175, 229, 230, 238, 420;
spectra of bright-line helium stars, 186, 233, 420;
of Wolf-Rayet stars, 237, 239, 242;
spectrum of Rigel, 191;
of Mira, 223–225;
of γ Argûs, 238;
bright lines in fourth-type spectra, 218;
star with a hydrogen envelope, 240, 244;
detection of spectroscopic binaries, 266, 296–298;
orbit of ζ Geminorum, 328–330;
constitution of Nova Aurigæ, 378;
its spectrum, 380, 381;
spectrum of Nova Normæ, 383;
of Nova Centauri, 384;
of Nova Sagittarii, 385;
of Nova Aquilæ, 386;
of planetary nebulæ, 479, 480, 491;
of Orion nebula, 500, 501;
of Trifid nebula, 503;
relative brightness of nebular lines, 476;
description of a bi-annular nebula, 491

Cannon, Miss, bright-line stars, 186, 235, 239;
variable stellar spectra, 250;
spectrum of η Carinæ, 370, _note_

Canopus, nature of spectrum, 182;
remoteness, 204

Cantor, electrically illuminated gases non-absorptive, 140

Capella, spectral relationships, 183, 205;
duplicity, 294–296, 297

Carbon, a solar constituent, 29, 31, 219;
spectral effacement in presence of iron, 34;
condensed in photospheric clouds, 63;
present in the chromosphere, 118;
in stars, 180, 184, 216, 219, 278;
no trace of in Wolf-Rayet spectrum, 242;
bright in R Geminorum, 246

Carbon stars, spectrographed, 177;
nature of spectra, 179, 184, 185, 215–220;
bright lines in, 185, 216–219, 408;
white specimens, 220, 258;
distribution, 221;
affinities, 238;
development, 277, 278;
luminous instability, 358–360

Carinæ, η, nature of spectrum, 235, 370;
light-changes, 370, 371, 406;
position in Key-hole nebula, 507

Carlyle, colour of Sirius, 256

Carrington, movements of sun-spots, 84;
law of the sun’s rotation, 143, 146, 149;
cyclical shiftings of spot-zones, 151

Cassiopeiæ, γ, bright-line spectrum, 186, 233, 234, 279;
spectral fluctuations, 248, 249

Castor, spectrum, 203;
a triple system, 293, 294;
dark companion, 293, 401

Centauri, α_{2}, spectrograph of, 182;
a model sun, 192, 199, 205, 269

Centauri, ω, variable stars in, 333, 436;
telescopic aspect, 429;
central crowding of components, 430

Cephei, δ, a typical short-period variable, 319;
orbital movements, 320, 321, 323;
analogous objects enumerated, 324–326;
their distinctive qualities, 327

Ceraski, discovery of U Cephei, 309

Ceraski, Madame, discoveries of variable stars, 316

Cerium, a solar element, 27, 30;
base of a rare earth, 33

Chacornac, supposed observation of a temporary nebula, 522, 523

Chamberlin, theory of spiral nebulæ, 445

Chandler, movements of the earth’s axis, 159;
disturbances of Algol, 304–306;
phases of eclipsing stars, 311, 314;
discovery of a Geminid variable, 326;
distinctive character of the class, 328;
variations of U Pegasi, 332;
cycle of Mira, 348;
of R Leonis, 356;
redness and periods of variable stars, 358

Chase, parallax of Algol, 306

Chemistry, scope of celestial, 6;
solar, 18, 21, 25–34;
of sun-spots, 91, 163;
of helium stars, 189;
of hydrogen stars, 197;
of Antarian stars, 210;
of carbon stars, 220;
of Mira variables, 226;
of Wolf-Rayet stars, 241

Chevremont, variable stars in the Pleiades, 421

Chromosphere, composition and depth, 16, 102, 109;
deficiency of absorptive power, 47, 161;
spectrum, 112–114, 116, 118, 119, 163

Clark, Alvan G., black markings in prominences, 110;
detection of additional trapezium stars, 230, 495

Cleve, rare metals, 33;
analysis of clevite, 57

Clevite, helium occluded by, 56

Colour variability, elusive of observation, 253;
relation to light-change, 254, 255;
incidental occurrence, 255–258;
in double stars, 259–262

Comets, mimicked by coronal rays, 127;
variation of conspicuousness with the solar condition, 158

Common, photograph of a globular cluster, 433;
variability of components, 434;
photograph of a cometary nebula, 446;
a triple group of nebulæ, 454

Comte, illusory forecast, 1

Copeland, helium-line in spectrum of Orion nebula, 174, 499;
colours of stars, 256, 257;
spectrum of U Orionis, 350;
of U Geminorum, 366;
spectroscopic detection of nebulæ, 480, 482

Cornu, telluric absorption, 22;
spectral series, 53

Corona, problem presented by, 9, 140;
tenuity, 16;
periodical variations, 20, 127–129;
structure, 123–127;
chromospheric relations, 129;
spectrum, 130, 131;
polarisation, 132;
photography, 132–136, 141;
dark markings in, 134;
rotation, 136, 141;
theories regarding, 137–140

Coronium, importance of in solar physics, 52;
subtlety, 60;
probable qualities, 61;
spectrum, 130;
non-absorptive, 140;
an unknown element, 141, 163

Cortie, structure of sun-spots, 76, 77, 80;
their alternations in activity, 85;
average duration, 86;
their spectra, 90, 91;
rotation of faculæ, 146;
spectral anomalies of Nova Persei, 392

Crab nebula, discovery, 517;
spectrum, 518

Crookes, Sir William, meta-elements, 33, 34

Crucis, β, a typical oxygen star, 190, 193

Cygni, β, colours and spectra, 264, 265

Cygni, χ, bright-line spectrum, 226, 227;
colour-changes, 255

Cygni, P, nature of spectrum, 186, 233, 234, 235;
irregular variability, 406

Cysatus, first notice of Orion nebula, 495

Dark stars, problem they present, 176, 177, 189;
probable origin, 276, 277;
coupled with bright stars, 289, 292, 293, 298, 317, 400, 401, 403;
two classes, 403;
galactic relations, 543

Darquier, discovery of annular nebula, 484

D’Arrest, drawing of a nebula, 443;
observations of nebulous stars, 454, 461, 465;
sharpness of 55 Andromedæ, 466;
stellar satellites to nebulæ, 483;
annular nebula, 493;
nondescript nebula, 520;
variable nebulæ, 523, 525, 526

Davidson, black markings in prominences, 110

Dawes, black openings in sun-spots, 75;
colour of δ Cygni, 261

De la Rue, stereoscopic view of a sun-spot, 81

Dembowski, colours of double stars, 260, 261

Deneb (α Cygni), spectral relationships, 193, 197

Denning, observations of a variable nebula, 528

Deslandres, photography of prominences, 9, 18, 98, 103;
selective photography of the sun, 49, 99;
facular flames, 100;
electrical origin of chromospheric luminosity, 115;
ultra-violet prominence spectrum, 119;
the sun as a bright-line star, 121;
coronal spectrograms, 132;
experiments on coronal rotation, 136, 137;
coronal heat, 141;
spectrum of Altair, 281, 284

Dewar, researches at low temperatures, 60

Dissociation, in sun-spots, 90, 96, 163;
of calcium, 114

Doberck, colour of Hind’s star, 257;
of γ Delphini, 260

Doppler’s principle, 4, 19, 106, 297, 390

Double stars, evolution, 176;
variable tints, 259–262;
spectra, 263–270, 275, 276;
indistinguishable from spectroscopic binaries, 297

Draco planetary, helical conformation, 474;
spectrum, 475

Draper Catalogue, 173

Draper, Henry, illusory bright oxygen-lines in solar spectrum, 28

Draper, J. W., illusory dark oxygen-lines in solar spectrum, 28

Dreyer, observation of a double nebula, 454;
non-nebulosity of 55 Andromedæ, 466;
alleged displacement of Omega nebula, 512;
observations of variable nebulæ, 528

Dumb-Bell nebula, analogous objects, 481, 517;
structure, 516;
spectrum, 517

Dunér, spectroscopic measures of the sun’s rotation, 19, 144, 145, 146,
147, 283;
spectra of sun-spots, 89, 90;
spectra of fourth-type stars, 216, 218, 219, 220;
colours of 95 Herculis, 260;
revolutions of Y Cygni, 311, 312;
minima of Z Herculis, 314

Dunlop, a blue cluster, 414

Dyson and Lewis, elongation of Capella, 295

East, refraction in sun-spots, 80

Eberhard, spectrum of χ Cygni, 226

Ebert, temperature of the sun, 66;
theory of the corona, 139, 140

Eclipses, solar, observations during, 9, 19, 20;
disclosure by of reversing layer, 44–46;
of prominences, 109, 120;
of coronal halo, 123, 125–128, 130, 162

Eclipses, stellar, 299–301, 317

Eclipsing stars, mean density, 272, 303, 307, 310, 313, 314;
rotational speed, 282, 283;
enumerated and described, 299, 318;
light-curves, 309, 317;
spectra, 316;
absent from clusters, 438

Eddie, light-change of δ Cephei, 321

Eisig, spectrum of oxygen, 28

Electricity, spectral influences imperfectly understood, 6;
undulatory, 22;
supposed effectiveness in chromospheric illumination, 115;
action of in corona, 137–140

Elkin, parallax of Capella, 295;
measurements of the Pleiades, 415

Ellerman, spectrographs of carbon stars, 185, 216;
of a Wolf-Rayet star, 239

Ellis, solar and magnetic periodicity, 154

Engelmann, colour of δ Cygni, 261

Espin, spectrum of α Herculis drawn by, 183;
catalogue of fourth-type stars, 215;
spectrum of φ Persei, 235;
of R Coronæ, 247;
colours of stars, 255, 256, 257;
light-change of R Cygni, 357;
suggested period of 63 Cygni, 369;
red stars in Perseus cluster, 412

Evershed, photographs of flash spectrum, 46;
constitution of reversing layer, 47, 48;
light from spot-umbræ, 75;
their spectra, 93;
prominence-spectrum, 112, 116, 119;
titanium in the chromosphere, 118

Fabricius, variability of Mira, 348, 349

Faculæ, connection with spots, 74, 101, 151, 153, 161;
status and distribution, 98, 100;
photographed, 99, 100;
rotation, 145–147

Faye, the sun’s rotation, 149

Fenet, map of stars in M 11, 410

Fényi, disturbance of reversing stratum, 50;
depth of chromosphere, 102;
observations of prominences, 103–108, 116

Finlay, parallax of Antares, 213;
magnitude of η Carinæ, 371

Fitzgerald, electrical relations of the solar corona, 140

Flammarion, colours of double stars, 260, 261

Flamsteed, nebulosity of 55 Andromedæ, 466, 467

Flanery, variations of R Scuti, 363, 364

Fleming, Mrs., discoveries and classification of variable stars, 186,
227;
detection of an eclipsing star, 316;
duplicity of β Lyræ, 338;
variability of W Puppis, 352;
of V Delphini, 356;
discovery of Nova Normæ, 382;
of Nova Centauri, 384;
of Nova Sagittarii, 395;
of a planetary nebula, 476;
spectrum of a star in Libra, 512

Fomalhaut, character of spectrum, 201, 202

Fowler, photographs of Indian eclipse, 130

Franks, colours of stars, 257, 260

Fraunhofer, survey of the solar spectrum, 21, 22

Fraunhofer-lines, their interpretation, 13, 17, 21, 26, 29, 34;
motion-displacements, 19, 42, 144;
unidentified residuum, 36;
variability, 37;
effects of pressure on, 38, 51;
structural complexities, 40, 41, 43, 243;
tranquillity of originating strata, 50, 154;
in sun-spots, 93, 146;
in faculæ, 98, 146;
in reflected coronal light, 132;
in spectrum of Andromeda nebula, 440

Frost, level of sun-spots, 79;
thermal power of umbræ, 81, 82;
refraction in the sun, 167

Gadolin, discovery of yttria, 33

Gale, discovery of an annular nebula, 489

Gallium, recognition in the sun, 28, 118;
in α Cygni, 193

Galton, description of solar corona, 123

Gautier, sun-spot and magnetic periods, 3

Geminorum, R, carbon-bands bright in spectrum, 246

Geminorum, U, diffuse aspect, 361;
light-changes, 365, 366

Geminorum, ζ, a typical short-period variable, 319, 328;
orbit, 329, 330;
members of its class, 331–335

Gill, Sir David, Cape Durchmusterung, 173;
spectrograph of α_{2} Centauri, 182, 269;
oxygen in stars, 191;
α_{2} Centauri a replica of the sun, 192, 199;
parallax of Sirius, 198;
of Fomalhaut, 202;
of Canopus, 204;
spectrum of η Carinæ, 235;
photograph of Argo nebula, 507, 508

Gilliss, redness of η Carinæ, 371

Goodricke, variability of β Lyræ, 337

Gore, discovery of U Orionis, 350

Gothard, bright lines in γ Cassiopeiæ, 248, 249;
spectral changes in β Lyræ, 338;
ultra-violet spectrum of Nova Aurigæ, 381;
of planetary nebulæ, 479, 482;
of annulus in Lyra, 488;
of dumb-bell nebula, 517;
photograph of nuclear star in Lyra nebula, 487

Gould, red stars, 258, 261;
variability of RS Sagittarii, 308;
of R Trianguli, 324;
of L_{2} Puppis, 352

Gravity, undiscriminating action, 2;
universality, 3;
maintenance of sun’s heat by, 14;
neutralisation of effects upon solar appendages, 16, 51, 60;
effectiveness in stars, 194, 201, 206, 207;
gain of power with condensation, 272;
influence on stellar temperatures, 274

Groombridge, magnitude of R Cephei, 369

Grosch, corona of 1867, 127

Grover, observations of variable stars, 254, 361

Gruss and Laska, spectrum of R Leonis, 227

Guthnick, long inequality of Mira, 348

Hagen, minimum of U Geminorum, 366;
periodicity of S Persei, 370

Hahn, nuclear star in Lyra annular nebula, 486

Hale, photography of prominences, 9, 18, 99, 110;
duplicity of D_{3}, 57;
carbon in the chromosphere, 118;
spectra of prominences, 118, 119, 121;
prominence-forms in daylight and during eclipses, 120;
magnetic relations of chromosphere, 157;
spectrographs of carbon stars, 177, 185, 216, 220;
bright lines in, 185, 217–219, 238;
spectrum of Nova Persei, 392

Hall, measurement of stars in Præsepe, 412;
invisibility of star in Lyra nebula, 486

Halley, aurora of 1716, 156;
magnitude of θ Eridani, 373

Halm, function of the sun’s smoke-envelope, 72;
effects of solar periodicity upon terrestrial movements, 158;
theory of temporary stars, 398

Hansky, dark markings on prominences, 111;
drawings of coronal types, 128;
coronal structure, 130, 140

Hartley, spectral series, 53;
gallium a chromospheric constituent, 118

Hartley and Ramage, detection of gallium-lines in solar spectrum, 28

Hartwig, minima of Z Herculis, 314;
light-change of S^2 Cygni, 367

Harzer, solar rotation, 148

Hasselberg, investigations of metallic spectra, 26;
vanadium in the sun, 32

Hastings, constitution of solar atmosphere, 71

Helium, a constituent of prominences, 19, 113, 119;
non-absorptive in the sun, 29, 56, 60, 93;
terrestrial discovery, 29, 56, 174;
spectrum, 57, 58, 113, 114;
properties, 59;
absorption in sun-spots, 94, 195;
a constituent of gaseous nebulæ, 174, 477, 478, 480, 499;
absorption in stars, 174, 181, 190, 191, 195, 225, 228;
emission in stars, 175, 186, 187, 226–228, 350;
in Nova Aurigæ, 376;
in Nova Persei, 393;
mixed bright and dark series, 229, 230, 238, 239;
in β Lyræ, 338;
yellow series represented in nebulæ, 536, 537

Helium stars, distinguished by Vogel, 174, 181;
characteristics and varieties, 189–195;
nebular relationships, 189, 190, 272, 277, 279, 462;
distribution, 196, 543;
pass into Sirian stars, 197, 272, 277;
with bright lines, 229–236, 248, 251;
mean density, 272

Helmert, catalogue of stars in M 11, 410;
their variability, 411

Helmholtz, gravitational hypothesis of solar sustentation, 14

Herschel, Alexander, spectral series, 53

Herschel, Caroline, discoveries of nebulæ, 441

Herschel, Sir John, nebulosity round ι Orionis, 190;
colours of stars, 258, 259, 412;
observations of clusters, 414, 425;
nebulosity of 15 Monocerotis, 426;
globular clusters catalogued, 428;
observations of nebulæ, 441, 443, 446, 447, 456, 458;
double nebulæ, 452, 453;
nebulous stars, 463, 464, 465, 466;
Owl nebula, 472;
bi-nuclear planetary, 480;
star satellites to planetaries, 483;
description of Lyra nebula, 484;
planetaries in clusters, 490;
brightness of a star in Orion nebula, 504;
stars in Argo nebula, 507;
drawing of Argo nebula, 508;
multiple star in Trifid nebula, 509, 510;
observation of Omega nebula, 511, dumb-bell nebula, 516;
its miniatures, 517;
observations of variable nebulæ, 526, 528

Herschel, Sir William, discovery of binary stars, 3;
division of 11 Monocerotis, 233;
colours of double stars, 259, 260;
observations of Mira, 348, 349;
nebulous stars, 460, 462, 463;
planetary nebulæ, 471, 481;
annular nebulæ, 484, 489, 493;
aspect of Trifid nebula, 509;
multiple star in, 509, 511;
variable nebulæ observed by, 526, 528;
dark hole in Scorpio, 541

Hevelius, magnitude of R Cephei, 369

Hind, red star, 256;
variations of S Cancri, 306;
of U Geminorum, 365;
detection of T Tauri, 372, 523;
of a temporary nebula, 523

Höffler, parallax of stars in Ursa Major, 290

Holden, polar rays of the corona, 139;
dark lanes in Hercules cluster, 432;
helical nebulæ, 474;
structure of annular nebulæ, 485, 490;
ansæ of Saturn nebula, 492;
suspected changes in Orion nebula, 503;
variability of a star within its compass, 504;
evidence of alteration in Omega nebula, 512;
duplicate nondescript nebulæ, 519

Hornstein, the sun’s rotation, 146

Howlett, conformation of sun-spots, 80, 81

Huggins, Sir William, foundation of spectrography, 3;
application of Doppler’s principle, 4;
daylight coronal photography, 20, 135;
atmospheric absorption, 22;
hydrogen spectrum, 52;
duplicity of D_{3}, 57;
electrical theory of corona, 138;
spectra of double stars, 166, 265, 266;
stellar classification, 180;
constitution of Nova Aurigæ, 378;
spectra of nebulæ, 443, 475, 512, 520;
nebulosity of 55 Andromedæ, 466;
temperature in nebulæ, 535

Huggins, Sir William and Lady, spectrum of calcium, 115;
nitrogen-absorption in stars, 175, 191;
spectrographs of Rigel, 181; of Vega, 182;
of Arcturus, 182;
of α Aquilæ, 282;
effect of gravity on stellar spectra, 201, 274, 276;
spectrographic investigation of trapezium stars, 231, 232;
Wolf-Rayet spectrum, 242;
spectra of double stars, 264, 270;
stellar temperatures, 273;
oxygen in β Lyræ, 338;
unknown ultra-violet nebular ray, 476, 503

Humphreys and Mohler, effects of pressure on spectra, 39

Hussey, observations of Capella, 295;
glimpse of Nova Centauri, 395

Huygens, variability of P Cygni, 234;
notice of Orion nebula, 495

Hyades, a non-nebulous cluster, 412

Hydrogen, ultra-violet spectrum, 3, 52;
a chromospheric constituent, 16, 19, 56, 112, 116, 117;
harmonic relations of spectral lines, 52, 53;
a second series observed in stars, 54, 175, 181, 187, 189, 195, 237,
239, 240, 465;
in nebulæ, 479;
escape from earth’s atmosphere, 55;
spectrum truncated in the sun, 56;
bright in sun-spots, 95;
in faculæ, 101;
absorptive effects in stars, 179, 181, 182, 191, 197, 203, 210;
bright in variables, 185, 222, 352;
in helium stars, 229–335;
in Wolf-Rayet stars, 237–241;
in β Lyræ, 338, 339, 340;
in Nova Aurigæ, 376;
in Nova Persei, 390;
in nebulæ, 476, 478, 488, 500–502, 536, 537;
triple structure of bright lines in Mira, 224, 225, 238

Hydrogen stars, spectral characteristics, 179, 182, 197–202;
development, 272;
temperature, 273

Ingall, structure of a ray nebula, 442;
of an annular nebula, 492

Innes, investigation of eclipsing stars, 316;
magnitude of η Carinæ, 371

Iron, absorption in solar spectrum, 30, 40, 41;
in spot spectra, 90, 92, 96;
in stellar spectra, 182, 184, 191, 210, 212, 220;
spectral prepotency, 34;
bright lines of, in Mira, 225;
in χ Cygni, 226

Janson, discovery of P Cygni, 234

Janssen, solar photographs, 17, 73, 76;
corona of 1871, 125;
Fraunhofer-lines in coronal spectrum, 132

Javelle, measures of a planetary nebula, 483

Jewell, variable Fraunhofer-line, 37;
effects of pressure on wave-length, 38;
structure of Fraunhofer-lines, 40, 41, 163;
titanium-lines in chromospheric spectrum, 118;
rotation of reversing layer, 147

Julius, solar phenomena explained by anomalous refraction, 147

Kant, nature of the creative process, 545

Kapteyn, stellar distribution and spectral diversity, 173, 543;
variability of R^2 Puppis, 316;
progressive illumination of nebulosity round Nova Persei, 395

Kayser, spectral series, 53

Kayser and Runge, metallic spectra, 26

Keeler, import of spectroscopy, 3;
calcium in the sun, 115;
helium-absorption in Rigel, 174;
radial velocities of nebulæ, 177, 470, 475, 483, 493, 499;
spectroscopic indication of high temperature, 181, 201;
bright lines in fourth-type spectra, 218;
spectrum of a Wolf-Rayet star, 239;
hydrogen-envelope of another specimen, 241;
spectrum of γ Cassiopeiæ, 249;
D-lines in β Lyræ, 344;
photographs of T Tauri, 373;
of nebulæ, 417, 443, 444, 487, 492, 493;
of cluster in Hercules, 432;
errors of draughtsmen, 447;
double nebulæ, 452;
rifted nebula, 456;
spectroscopic experiment on rotation of a nebula, 469;
drawings of planetaries, 470, 478, 479, 490;
description of Owl nebula, 473;
Webb’s planetary, 480;
spectrum of a stellar nebula, 481;
structure of Lyra nebula, 485;
central star, 487;
hydrogen spectrum in nebulæ, 499, 500;
screened photograph of Orion nebula, 501;
ultra-violet ray in spectrum, 503;
spectrum of Trifid nebula, 510;
multiple star in, 511;
photographs of Hind’s variable nebula, 524, 525

Kepler, laws enounced by, 1;
prescience of, 2;
letter to Herwart, 542

Key, structure of annular nebula, 493

Key-hole nebula, relations to of scattered stars, 507;
extinction of one of its parts, 508;
spectrum, 509

Kirch, discovery of a globular cluster, 433

Kirchhoff, interpretation of Fraunhofer-lines, 13

Kirchhoff’s law, disregarded by solar helium, 93;
by nebular gases, 462, 467

Klinkerfues, parallax of Mizar, 290

Knopf, optical rationale of reversing layer, 166

Knott, nebulous aspect of U Geminorum, 361

Koch, variability of R Leonis, 355

Köhl, fading of a red star, 374

Konkoly, spectrum of γ Cassiopeiæ, 249;
of U Orionis, 350

Krüger, spectrum of R Leonis, 227;
of R Scuti, 248;
colours of stars, 256–258

Lagoon nebula, involves a cluster, 424

Lalande, observation of S Ursæ Majoris, 353;
of Draco planetary, 474

Lamont, measurements of M 11, 410;
possible temporary star in, 411

Lane, cometary forms in solar corona, 126;
heating of gaseous globes through condensation, 272, 273, 276

Langley, bolometric survey of infra-red spectrum, 22, 24;
selective absorption in solar atmosphere, 64, 70;
heat stoppage in terrestrial atmosphere, 65;
relation of temperature to spectral energy-curve, 66;
heat of sun-spots, 82;
observations during solar eclipses, 123, 127;
multiple star in Trifid nebula, 511;
glow of white-hot iron, 532

Laplace, self-absorption of sunlight, 70;
dark stars, 400

Lassell, star in a double nebula, 454;
description of a planetary nebula, 481;
observations of annular nebulæ, 489, 490, 493;
of Trifid nebula, 509;
multiple star in, 511

Le Chatelier, temperature of the sun, 66

Le Gentil, companion to the Andromeda nebula, 441

Lehmann-Filhés, orbit of β Aurigæ, 291

Lewis, spectra of mixed vapours, 34

Liais, black-edged prominence, 110;
drawing of solar corona, 127

Lindemann, observations of V Cygni, 359, 361

Littrow, triple nebula, 454

Liveing and Dewar, spectrum of liquid oxygen, 23;
heat-relations of magnesium-lines, 49;
spectral series, 53;
spectra of rare atmospheric gases, 114, 120

Lockyer, Sir Norman, application of Doppler’s principle to the sun, 19;
detection in the sun of carbon and vanadium, 31, 32;
disappearance of a Fraunhofer-line, 37;
photographs of flash spectrum, 46;
periodical changes in spot spectra, 89;
solar dissociation, 90, 96, 114;
enhanced lines in chromospheric spectrum, 119;
corona of 1871, 125;
wave-length of green coronal ray, 130;
spectrum of Bellatrix, 191;
of α Cygni, 193;
of α Aquilæ, 281;
of S Sagittæ, 325;
temperature of electric spark, 273;
system of β Lyræ, 339, 340;
meteoric hypothesis, 451, 534

Lockyer, Dr., disturbances of η Aquilæ, 323

Lohse, O., investigation of cerium spectrum, 30;
photographic measures of cluster in Perseus, 411

Looped nebula, peculiar spectrum, 251, 512

Lord, spectrum of a prominence, 116

Luizet, phases of U Vulpeculæ, 324

Lunt, spectrum of ε Canis Majoris, 182;
silicon in stars, 182, 191, 193

Lyræ, β, variability in light, 337;
spectrum, 338;
changes in, 339, 343–345;
system, 338–342, 345;
analogues, 345, 346

Lyra, ring nebula in, 484–488

McClean, photograph of a telluric band, 23;
spectroscopic character of the Milky Way, 173, 196, 543;
oxygen in stars, 175, 232, 239;
stellar classification, 180, 197;
importance of helium stars, 181;
spectral quality of early stars, 189;
spectrograms of γ Cygni, 204;
of Antarian stars, 211;
of η Carinæ, 235;
system of β Lyræ, 339;
spectrum of ι Orionis, 465

Mädler, corona of 18th July 1860, 123;
satellite of Mizar, 291

Magellanic clouds, analogy to Milky Way, 187, 242, 544;
Wolf-Rayet stars contained in, 242;
nebulæ, 512, 517

Magnetism, terrestrial, periodicity coincident with that of sun-spots,
3, 154;
sympathetic response to solar agitations, 156–159

Maia, light-power, 415;
attached nebulosity, 417, 446, 522;
suspected slow light-change, 421;
spectrum, 532

Mason and Smith, observations of Trifid nebula, 509

Maunder, pressure in reversing layer, 49;
helium spectrum, 58;
structure of sun-spots, 83;
duplicated disturbances, 85;
white prominences, 110;
coronal extensions, 134;
coronal photographs, 135;
eruptive nature of prominences, 137;
movements of spot-zones, 152;
solar periodicity, 156, 157;
constitution of nebulæ, 534

Maunder, Mrs., coronal photographs, 134;
nature of prominences, 137

Maury, Miss, stellar classification, 180, 181, 182, 183, 185, 186, 189,
192, 194, 197, 202, 205, 207, 210, 218;
spectrum of Fomalhaut, 201;
composite spectra, 265, 266, 298;
diffuse lines in stellar spectra, 282;
duplicity of β Aurigæ, 291;
system of β Lyræ, 339, 340

Maw, black holes in sun-spots, 76;
submerged bridges, 79

Méchain, discovery of a nondescript nebula, 519

Mendenhall, characterisation of astrophysics, 9

Merope, brightness, 415;
attendant nebulæ, 416, 417;
suspected variability, 421;
spectrum, 532

Messier, description of Crab nebula, 518

Metalloids, in the sun, 29;
facility of spectral effacement, 34

Metals, in the sun, 26, 30;
in stars, 181, 182, 183, 184, 189, 195, 197, 201, 203, 209;
emission by in stellar spectra, 225, 234, 284;
absence from nebulæ, 278

Michelson, temperature and energy spectrum, 66

Milky Way, photographic study of, 7, 539, 540;
a distinctive spectroscopic region, 173, 542;
frequented by Wolf-Rayet stars, 187, 242, 543;
by helium stars, 196, 236, 543;
by carbon stars, 221;
by temporary stars, 396, 402, 543;
by gaseous nebulæ, 398, 506, 544;
by globular clusters, 448, 545;
problem of construction, 538;
dark openings in, 540, 541;
magnitudes of component stars, 542

Mira, character of spectrum, 185, 222, 223;
multiple hydrogen rays in, 224, 225;
radial motion, 224;
redness, 254;
vicissitudes detected, 348;
inconstancy of their method and amount, 349

Mitchell, hydrogen spectrum in Orion nebula, 499

Mizar, a spectroscopic binary, 289;
nature of system, 290

Monck, theory of temporary stars, 379;
preferential visibility of white stars, 543

Moon, projectile character, 2;
photographically studied, 7

Morin, drawing of the corona, 133

Motion-displacements of spectral lines, 4, 5, 286;
in the sun, 19, 38, 42, 105, 108, 109, 283;
in Mira, 224;
by rotation in stars, 280–283;
in binary systems, 288, 289, 291, 292, 295;
in eclipsing pairs, 300, 302, 303, 307;
in short-period variables, 320, 329, 334;
in β Lyræ, 338–341, 343

Müller, F., double nebula, 453

Müller, G. and Kempf, variability of ST Cygni, 325;
of U Vulpeculæ, 334;
of X Persei, 369;
photometric catalogue of the Pleiades, 421

Myers, system of U Pegasi, 332;
of β Lyræ, 341, 342

Naegamvala, photographs of flash spectrum, 46;
helium-absorption in sun-spots, 94

Nebulæ, connected with temporary stars, 384, 394, 395;
photographic surveys, 443, 449;
irregular, 506;
nondescript, 516–521;
variable, 522–530;
distribution, 544, 545

Nebulæ, gaseous, peculiarities of light, 173, 251, 536, 537;
helium emissions from, 174, 175, 491, 499;
radial velocities, 177, 470, 475, 483, 493, 499;
the matrices of stars, 271, 469, 486, 490, 495;
temperature, 502, 535, 536;
feeble luminosity, 532;
tenuity, 533, 534, 536;
meteoric hypothesis of constitution, 534, 535

Nebulæ, white, difficulty of spectral investigation, 174, 439;
spirality, 440–446;
rifted, 447, 448;
avoidance of Milky Way, 448;
double, 452–458;
clustering tendency, 458;
probable composition, 531

Nebular physics, inseparable from stellar physics, 171;
conditions of progress, 173, 174

Nebulium, absorptive incapacity, 465, 532;
denser than hydrogen, 476;
terrestrially unknown, 476, 502

Nebulous stars, luminous stability, 406;
Herschel’s notice of, 460;
distinction from planetary nebulæ, 461;
spectra, 462, 465, 467;
frequently compound, 463–465;
doubtful instances, 463–467;
desirable inquiries, 467, 468;
non-absorptive surroundings, 532

Newall, experiments on coronal rotation, 136;
duplicity of Capella, 294

Newcomb, constitution of the solar corona, 138

Nitrogen, absorption-lines in stellar spectra, 175, 181, 191, 195, 232,
235

Nordenskiöld, notice of clevite, 56

Nova Andromedæ, 385, 411, 450

Nova Aquilæ, nebular transformation, 386

Nova Aurigæ, photographic investigation, 175, 376, 382;
sudden rise, 375;
theories regarding, 377–379;
nebular phase, 379, 381;
light-curve, 380

Nova Carinæ, changes in spectrum, 383

Nova Centauri, apparition, 251;
spectrum, 384

Nova Cygni, nebular transformation, 382

Nova Normæ, photographic discovery, 382;
metamorphosis into a nebula, 383

Nova Persei (1887), spectrographic record of apparition, 384

Nova Persei (1901), sudden rise, 388;
blazing spectrum, 390;
light-curve, 391;
spectral alterations, 392, 393;
nebulous environment, 394, 395

Nova Sagittarii, spectrographic records, 385

Olbers, electrical theory of comets, 3

Omega nebula, conformation, 511;
alleged, change, 512

Oppolzer, solar absorption, 71;
meteorological theory of the sun, 164

Orbinsky, measurements of a globular cluster, 436

Orion nebula, helium-ray in spectrum, 174, 499;
photographic extensions, 190, 495–497;
nuclear star-group, 230–232, 495–497;
scattered stars in, 498;
hydrogen-radiations from, 499–502;
unknown ultra-violet line in spectrum, 502, 503;
suspected variations, 503;
variable stars in, 504;
low mean density, 533

Owl nebula, observational history, 472, 473;
photographs, 473