Appendix

Appendix

TABLE I

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

Oxygen, telluric absorption by, 22, 23; presence in the sun, 26, 27, 29; dark lines of in stellar spectra, 175, 181, 191, 195, 232, 239, 241, 338, 465

Packer, variable stars in cluster, 433

Palmer, distribution of stars in Hercules cluster, 432

Parkhurst, phases of Y Boötis, 313, 314; irregularity of U Geminorum, 366; light-curve of S^2 Cygni, 367

Paschen, temperature and energy spectrum, 66

Peek, Sir Cuthbert, work at observatory, 254; light-curve of S Ursæ Majoris, 353; light-change of R Lyncis, 356

Pereira, description of a sun-spot, 75; drawing of a sun-spot, 78

Perrine, expansion of nebulosity about Nova Persei, 394

Perrotin, colours of double stars, 259, 261

Perry, Father, dark helium-line in sun-spot spectra, 94

Perry, Professor, masses and temperatures of stars, 274

Peter, measurements of clusters, 189, 426

Photography, advantages, 3, 5; lunar, 7; double slit, 9, 18, 50; solar, 17, 25, 49; chromospheric, 18, 99, 100, 114; of reversing layer, 45, 46; of corona, 132–135; of temporary stars, 175, 376, 382, 387, 388, 392; of nebulous stars, 190, 462, 464, 465, 466; of irregular nebulæ, 205, 507, 508, 509, 511, 513–515; of Nova Persei nebula, 394, 395; of Pleiades nebulosities, 416–420; of white nebulæ, 442–444, 448, 449, 455, 458; of planetary and annular nebulæ, 472, 484, 487, 490, 493; of Orion nebula, 495–497; of variable nebulæ, 525, 529; of Milky Way, 539–541; with portrait-lenses, 423, 513

Photometry, its dual aspect, 8; of the Pleiades, 421

Photosphere, a limiting surface, 15, 16; temperature, 49, 64–66, 69; constitution, 62, 63, 69, 70; problem of formation, 402

Piazzi, nebulosity of 55 Andromedæ, 466, 467

Pickering, E. C., discovery of a second hydrogen series, 54, 237; general absorption in solar atmosphere, 70; spectral character of galactic stars, 173, 196; fifth stellar type, 188; spectrum of Procyon, 203; of 11 Monocerotis, 233; of Wolf-Rayet stars, 239, 240; composite stellar spectra, 265; rotation of Altair, 281; eclipses of Algol, 302, 303; light-curves of eclipsing stars, 309; phases of U Cephei, 310; of W Delphini, 315; of S Antliæ, 331; binary character of V Puppis, 334; of β Lyræ, 338; light-curve of T Andromedæ, 357; spectrum of U Geminorum, 366; of Nova Persei, 392; photograph of Nova Persei, 388; spectra of stars in Præsepe, 413; counts of Pleiades, 416; surmised cause of cluster-variability, 436; catalogue of stars in M 5, 438; detection of stellar nebulæ, 481, 482; spectrum of Looped nebula, 512

Pickering, W. H., spectrum of white prominences, 110; photographs of nebulæ, 190; of Orion trapezium; of colossal involving nebulosity, 496; movements of the entangled stars, 497; estimated distance, 498; spectrum of Orion nebula, 503

Pigott, discovery of R Scuti, 363; of R Coronæ, 371

Planetary nebulæ, affinities, 188; criteria of distinction from nebulous stars, 461, 469; spheroidal in shape, 469; radial velocities, 470, 475, 483; complex structure, 471; nuclear stars, 473, 474, 532; spectra, 475–479; bi-nuclear, 480; distribution, 544

Plassmann, light-change of λ Tauri, 307

Pleiades, helium spectra, 181, 194, 413, 420; nebulously involved, 189, 230, 416–420; general stability in light, 406, 421; drifting movement, 409, 415; a typical nebulous cluster, 415; fewness of real components, 416; recession from the sun, 420; centrifugal tendency, 497

Pluvinel, Fraunhofer-lines in coronal spectrum, 132

Pogson, variability of S Ursæ Majoris, 353; of R Cephei, 369

Polaris, spectrum, 205; triple system, 298; constant brightness, 327

Pollux, estimate of mass, 206

Porro, light-curve of U Orionis, 350

Præsepe, measures of components, 412; their spectra, 413

Pritchard, parallax of β Aurigæ, 291

Proctor, refraction in sun-spots, 80

Procyon, spectral relationships, 182, 203; mass, 204; semi-obscure companion, 400

Prominences, chromospheric outgrowths, 16, 19, 101; photography, 18, 99, 109; varieties, 102, 103; movements in, 103, 106–109; structure, 103, 105, 109; diametrical situations, 106; white and black, 110, 120; spectrum, 115–121; relations with coronal jets, 129, 130; ejective character, 137; movements in latitude, 153

Pupin, coronoidal discharges, 140

Pye, observation of reversing layer, 44

Rambaut, orbit of β Aurigæ, 291

Ramsay, discovery of helium, 29, 56; its electric conductivity, 59

Ranyard, photograph of a sun-spot, 76; coronal structures, 126; coronal types, 128; central star in Lyra nebula, 487; conformation of Orion nebula, 496; allineation of stars in Key-hole nebula, 507; dimness of nebulæ, 532; their small mean density, 533, 534

Red stars, Antarian, 179, 183, 209; carbon type, 179, 184, 215; variable in tint, 254–258; in light, 352, 370, 374; relation of colour-intensity to length of period, 358

Reed, halts in stellar light-change, 359

Refraction, effects of in sun, 165–167

Regulus, a helium star, 184

Reversing layer, disclosure during eclipses, 9, 44; position in the sun, 16, 46, 161; photographed, 45, 46; analysis, 47, 48, 162; temperature, 49; tranquillity, 50; slight pressure in, 51; optical rationale, 166, 167

Riccò, level of sun-spots, 80

Rigel, absorption in by helium, 174, 181, 191; by silicon, 193; luminosity, 192

Ritchey, expanding nebula round Nova Persei, 394

Ritter, star-masses and temperatures, 274, 276

Roberts, A. W., system of RS Sagittarii, 308; detection and investigation of eclipsing stars, 313, 314, 316; phases of δ Cephei, 320; of R Trianguli, 324; of R^2 Centauri, 331; of V Puppis, 334; of S Aræ, 336; magnitude of η Carinæ, 371

Roberts, Isaac, photographs of a circular nebula, 190, 514; of clusters, 410, 433, 436; of the Andromeda nebula, 440; of other spirals, 441, 442; of rifted nebulæ, 447, 448; of a nebulous star, 465; of Owl nebula, 472, 473; of annular nebulæ, 489, 490; of Trifid, 509; of Omega nebula, 511; of nondescript nebulæ, 517, 518, 519, 520; photographic search for a vanished nebula, 525

Robinson, observation of the Owl nebula, 472

Rosetti, solar temperature, 65

Rosse, Lord, arrangement of stars in M 37, 410; nebulosity of 15 Monocerotis, 426; perforated cluster, 435; ray nebula, 442; spiral nebulæ, 443, 444, 445; cometary nebula, 446; observation of 55 Andromedæ, 466; Owl nebula, 472, 473; central stars in annular nebulæ, 486, 489, 493; Crab nebula, 518; contours of gaseous nebulæ, 534

Rotation, solar, spectroscopically determined, 7, 19, 144, 145; from spot-movements, 83, 142, 143; from faculæ, 145, 146; attempted explanation of anomalies, 147–149; theoretical effects in stellar spectra, 280, 281; unapparent to observation, 282–284; of planetary nebulæ, 469, 470

Rowland, invention of concave gratings, 18; map of solar spectrum, 25; solar chemistry, 25, 26, 30, 31, 32; photographs of metallic spectra, 26, 91; variable Fraunhofer-line, 37

Rubens, temperature and spectral energy-curve, 66

Runge, duplicity of clevite-ray, 57; hydrogen-envelope of a star, 241; spectrum of Orion nebula, 501

Runge and Paschen, oxygen triplet in solar spectrum, 29; spectral series, 53, 54; spectrum of helium, 57, 58

Russell, H. C., movements of stars in Jewel cluster, 414; photographic and visual observations of Key-hole nebula, 507, 508; photographs of Coalsack region, 540; of nebulæ, 544

Russell, H. N., density of eclipsing stars, 307, 308, 310

Rydberg, spectral series, 53; third hydrogen series, 187, 190, 232, 237, 238, 240

Sabine, sun-spot and magnetic periods, 3, 13

Safarik, periodicity of S Persei, 370

Sampson, origin of the solar rotation, 148

Savélieff, solar radiation, 68, note

Sawyer, variability of U Ophiuchi, 311; of R Canis Majoris, 313; of RX Herculis, 315; of T Vulpeculæ, 325; luminous outbursts of R Lyræ, 368; minimum of R Coronæ, 372

Schaeberle, perspective effects in corona, 124; coronal photographs, 126, 129; ejective theory of corona, 137, 165; conformation of nebulæ, 474, 492; photograph of a nebula, 515

Scheiner, heat-relations of magnesium-lines, 49, 181, 187, 200, 201; locus of general absorption in sun, 71; temperature of the corona, 138; search for electrical vibrations in sunlight, 159; carbon bands in stars, 184; constitution of solar stars, 207; temperature of electric spark, 273; incipient brightening of stellar hydrogen bands, 284; photographic catalogue of stars in M 13, 433; spectrograph of Andromeda nebula, 439; photographs of nebulæ, 493, 513; measurement of stars in Orion nebula, 498; hydrogen spectrum in nebulæ, 499, 502

Schiaparelli, colour of Sirius, 255

Schjellerup, red stars, 256–258; observation of 55 Andromedæ, 466

Schmidt, A., optical theory of the sun, 165, 166

Schmidt, J., colour of Algol, 256; low minimum of S Cancri, 306; detection of a group of variables, 325; fluctuations of ζ Geminorum, 328; periodicity of υ Herculis and R Lyræ, 368; minima of R Coronæ and of ε Aurigæ, 372

Schönfeld, period of R Lyræ, 368; variable nebula, 528

Schultz, central star in Lyra nebula, 486

Schumann, constitution of Nova Aurigæ, 378

Schur, light-curve of η Aquilæ, 321; catalogue of stars in Præsepe, 412

Schuster, spectral series, 53; variations in the electrical conductivity of space, 158

Schwab, phases of U Sagittæ, 316

Schwabe, discovery of sun-spot period, 13

Schwarzschild, orbit of β Aurigæ, 291

Searle, invisibility of star in bi-annular nebula, 490

Secchi, darkening of sun’s limb, 70; rosy veils in spot umbræ, 77; eruptive hypothesis of solar constitution, 165; localisation of stellar varieties, 173, 179, 181, 185, 186; bright lines in fourth-type spectra, 185, 216; spectrum of α Herculis, 211; of “La Superba,” 217; of γ Cassiopeiæ, 233, 249; of β Lyræ, 338; colours of double stars, 260, 261; central star in Lyra nebula, 486; annular nebula in Gemini, 493; disappearance of Hind’s nebula, 523

See, evolution of double stars, 166, 333, 452; elements of Sirius, 198; colour of Sirius, 255; double nebulæ, 452

Seeliger, selective absorption in the sun, 71; solar refraction, 167; encounter-hypothesis of Nova Aurigæ, 377; theory of stellar outbursts, 379

Shackleton, photograph of flash spectrum, 19, 45

Sidereal physics, defined, 171; an extension of solar physics, 172; scope, 177; connection with sidereal mechanics, 287

Sidgreaves, variable Fraunhofer-line, 37; convexity of spot-umbræ, 80, 81; observation of a prominence, 119; rotation of faculæ, 146; eruptive hypothesis of solar constitution, 165; spectrographs of Mira, 185, 223; of γ Cassiopeiæ, 187; of β Lyræ, 339; spectrum of Nova Aurigæ, 379; of Nova Persei, 390, 391, 392

Silicon, a constituent of the sun, 27, 29; of stars, 181, 182, 191, 193, 195, 198, 232

Sirius, silicon-absorption in, 193; spectral character, 197, 200, 201; mass and brightness, 198, 199; colour in antiquity, 255, 256; dusky satellite, 400

Smyth, Admiral, colours of double stars, 259, 260; gold-dust cluster, 414; a red satellite star, 464

Smyth, Piazzi, experiments on solar heat-radiation, 68; colours of 95 Herculis, 260; redness of η Carinæ, 370

Solà, Comas, triangulation of cluster in Sagittarius, 424

Solar physics, wide range of, 8; definition, 13; altered standpoint, 14; methods and character of progress, 17, 20, 150; illustrated by sidereal research, 172

Solar stars, characteristics, 182, 205; transition from hydrogen stars, 203; giant specimens, 205, 206; minor orbs, 206, 207; transition to Antarian stars, 207

Spectra, nebular, difficulty of investigating, 173, 174; continuous, 439, 440; gaseous, 475–480, 488, 491; relative strength of constituent lines, 476, 479, 499–502; of variable formations, 529

Spectra, stellar, local diversities, 173, 187, 196; classification, 179–188; banded, 179, 183, 184, 207, 209–220; with bright lines, 185–188, 217–220, 222–235, 237–245, 407, 408; variable, 227, 247–252; anomalous, 246, 247, 251; dissimilarly coupled, 263–268, 276; relations to colour, 263, 270; evolutionary succession, 271–278; of Algol variables, 316; of Cepheid variables, 327; of Mira variables, 360; of Novæ, 397; of clusters, 413, 414; free from nebular absorption, 532; galactic types, 543

Spectrography, importance of, 3, 4, 38, 122, 234; detection of binary systems by, 289; applied to temporary stars, 376, 384, 385; to clusters, 413; to nebulæ, 439, 476, 502

Spectroscopic binaries, discoveries, 176, 289–298; of dissimilar light-quality, 266, 295; effects of rotation on, 283; nature of evidence regarding their movements, 288; classification, 289

Spectrum, solar, visible section, 21; infra-red, 24; photographic, 25; thronged with absorption-lines, 36; peculiarities, 37–42, 162; telluric, 23, 24; of oxygen, 28; of helium, 29, 57, 58, 113, 114, 174; of carbon, 31; of reversing layer, 44–48; of hydrogen, 52–54; of coronium, 60, 130; of sun-spots, 88–96; of faculæ, 98, 100; of chromosphere and prominences, 112–121, 163; of the corona, 130–132, 163

Spectrum analysis, import of, to astronomy, 3; to solar physics, 14

Sperra, light-change of S Antliæ, 331

Spica, a spectroscopic binary, 292

Spiral nebulæ, examples, 440–446, 487; prevalence, 443; explosive theory, 445; simulate duplicity, 453

Spitaler, drawings of nebulæ, 456, 457, 458, 526; measurements of nebulæ, 483; invisibility of central star in Lyra nebula, 487

Spörer, shiftings of sun-spot zones, 151, 152

Star-clusters, globular, structural plan, 409, 428; examples, 429–436; non-nebulous, 433; nests of variables, 434, 435, 436–438; frequent the Milky Way, 448

Star-clusters, irregular, conformation, 409; examples, 410–414; nebulous, 423–427

Stars, classification, 179; evolution, 271–279; rotation, 280–285

Stefan, law of radiation, 64

Stellar nebulæ, limited to the Milky Way, 544

Stephan, nebulous star, 467; discovery of a nebula, 479

Stone, Ormond, aspect of Orion nebula, 503; varying brightness of contained stars, 504

Stoney, spectral series, 53; escape of gases from planetary atmospheres, 55; composition of photosphere, 63

Stratonoff, rotation of the sun, 83; of faculæ, 145, 147; counts of the Pleiades, 416; nebulosities of the Pleiades, 418

Struve, O., division of γ Andromedæ, 266; mass of η Cassiopeiæ, 268; observation of bi-annular nebula, 490; disappearance of a star in Orion nebula, 504; discovery of a temporary nebula, 524

Struve, W., colours of double stars, 259, 261; duplicity of Atlas, 421; triplicity of 15 Monocerotis, 426

Sun, new views regarding, 14, 15; appendages, 15; chemistry, 18, 21, 25–34, 163; spectral peculiarities, 36–43, 162, 163; conformation, 62, 161; general atmospheric absorption, 64, 65, 69, 70, 71; radiation, 64, 65, 68, 151, 159; temperature, 65–67, 69; photospheric veil, 71, 72; a bright-line star, 121, 154; mode of rotation, 142–149, 161; periodicity, 150–160, 162; a variable star, 151, 362; theories of constitution, 164–167; a solitary body, 172, 282; motion in space, 192, 415; stage of development, 274

Sun-spots, periodicity, 3, 13, 150–152; doubts regarding, 9, 86, 87; spectra, 72, 88–97, 163, 195; structural features, 73, 75–77; relations to faculæ, 74, 161; groupings, 77–79, 85; question of level, 79–83, 86; heat-emissions, 81, 82, 164; movements, 83–85, 96, 142, 144; dimensions, 85; chemistry, 91; scarcity in seventeenth century, 156; magnetic relations, 154–158; nature and origin, 162, 164; refractive effects in, 167

Swift, black lines in prominences, 110; nebulosity in Monoceros, 425; hairline nebulæ, 442; double nebulæ, 455, 457; nebular groups, 458; nebulous stars, 462, 463; new features in Trifid and Omega nebulæ, 522; observation of a variable nebula, 527

Sykora, measures of the sun’s diameter, 74

Tacchini, daylight extent of chromosphere, 109; white prominences, 110, 120; coronal relations of prominences, 129; magnetic influences of the chromosphere, 157

Telluric absorption, 22–25

Tempel, discovery of Merope nebula, 416, 522; drawing of a spiral nebula, 443; Chacornac’s nebula, 523; observation of Struve’s temporary nebula, 525

Temperature, of reversing layer, 49; relations of to hydrogen spectrum, 54, 201; in solar photosphere, 63–67, 69; in sun-spots, 92, 96, 164; in solar corona, 138, 140; in stars, 193, 195, 199–201, 273, 274; in nebulæ, 502, 535

Temporary nebulæ, 524, 526, 528, 529

Temporary stars, spectral character, 175, 397; recent apparitions, 375–396; photographic discoveries, 382–387; summary of facts regarding, 396–398; galactic proclivities, 396, 402, 543

Theodorus, observation of η Carinæ, 371

Thome, colour of η Carinæ, 371

Thomson, electrical affinities of hydrogen-lines, 112

Tisserand, disturbances of Algol, 305, 306; of U Cephei, 310

Titanium, absorption by in the sun, 32, 49; in spots, 91, 92; in stars, 192, 193, 198, 226, 232; bright lines of in flash and chromospheric spectra, 47, 118

Toucani, 47, globular cluster, 431, 436

Trapezium stars, composition of group, 230; spectrum, 231, 232, 498, 532; inconspicuously variable, 406; photographed, 495; proper motion, 497, 498

Trifid nebula, nuclear multiple star, 406, 510; conformation, 509, 510; spectrum, 510

Trouvelot, veiled spots, 102; observations of prominences, 106, 110

Trowbridge, spectroscopic experiments, 34

Trowbridge and Hutchins, carbon in the sun, 32

Turner, photographs of the corona in polarised light, 132

Tuttle, discovery of a variable nebula, 527

Vanadium, a constituent of the sun, 32, 49; of prominences, 119; of Sirius, 198; prominence of absorption in spot-spectra, 91, 92; emission in γ Cassiopeiæ, 234, 249

Variable nebulæ, evasive of recognition, 522; authentic examples, 523–528; problem of, 529

Variable stars, solar analogy, 151, 176, 362, 406; their helium emissions, 175, 226, 228; open to research, 175, 176; in clusters, 177, 319, 335, 336, 433–438; with fourth-type spectra, 215, 358–360; with bright-line fluted spectra, 222–228, 407; with anomalous spectra, 246–248; redness, 253–255, 352, 358; of short period, 319–336, 404; of long period, 347–362; irregular, 363–374, 405; correlation of spectrum and period, 406–408

Variable stellar spectra, an inexplicable phenomenon, 227; examples, 247–252, 338, 339, 344

Vega, spectrographed, 182; character of spectrum, 197, 198, 201; remoteness, 200

Very, photospheric radiation, 67, 68; nebulous formation round Nova Persei, 395

Vogel, H. C., spectrographic investigation of radial motion, 4; solar atmospheric absorption, 70, 71; helium stars, 174, 181; stellar classification, 180, 277; carbon stars, 184, 277; fluted spectra, 211, 277; spectrum of Mira, 223; of a Wolf-Rayet star, 239; of R Geminorum, 246; of γ Cassiopeiæ, 248; of β Cygni, 265; of 95 Herculis, 267; of Capella, 294; of β Lyræ, 339, 344; colour of γ Delphini, 260; rotation of Altair, 281; period of Mizar, 290; duplicity of Spica, 292; composition of Nova Aurigæ, 378; radial motion of Nova Persei, 390; structure of a planetary nebula, 471; observations of annular nebulæ, 487, 490, 493; invisibility of a nebula, 528

Vogel, H. W., fifth hydrogen-line, 52

Wadsworth, small apertures for nebular photography, 423, 496

Webb, colours of double stars, 259, 261; discovery of a planetary nebula, 479

Weiss, coronal structure, 126

Wells, Miss, discovery of W Delphini, 315; of S^2 Cygni, 366

Wendell, photometric measures of U Pegasi, 332

Wesley, study of, and drawings from coronal photographs, 125, 126, 134, 135

Wiedemann, effects of luminescence, 243, 397

Wilczynski, mode of solar rotation, 148

Williams, Stanley, discoveries of eclipsing stars, 316; of V Puppis, 334

Wilsing, rotation of faculæ, 145; of the sun, 148, 149; absence of Hertzian vibrations in sunlight, 159; luminescence of temporary stars, 397; system of 61 Cygni, 403

Wilson, Alexander, perspective effects in sun-spots, 79, 80

Wilson, H. C., structure of Maia nebula, 417; exterior Pleiades nebulosity, 419

Wilson, W. E., heat of sun-spots, 82; nebula round Nova Persei, 395; photographs of nebulæ, 444, 445, 484, 516

Wilson and Gray, determination of the sun’s temperature, 64, 65, 67; variable radiation, 68

Wilson and Rambaut, arrest of heat in solar and terrestrial atmospheres, 65, 69

Winkler, detection of germanium, 33

Winnecke, coronal observations, 123, 126; measures of stars in Præsepe, 412; variability of 15 Monocerotis, 425; description of Webb’s nebula, 479; indications of nebular variability, 528, 529

Wolf, C., map of the Pleiades, 421

Wolf, Max, photographs of galactic nebulosities, 205, 514; of the place of Nova Aurigæ, 375; of the Nova Persei nebula, 394; of the Pleiades nebulosities, 418; of planetaries, 482; electrical rationale of Nova Persei nebula, 395; photographic nebular survey, 449, 544; a cluster of nebulæ, 458; nebular distribution, 544, 545

Wolf, R., sun-spot and magnetic periods, 3, 154

Wolf-Rayet stars, metals unapparent in, 175; spectrographs, 177; galactic distribution, 187, 242, 543; nature of spectra, 188, 237–240, 284; affinities, 195, 217, 218, 246, 278, 440; specimen with a hydrogen-envelope, 240, 241, 244; stability in light, 406

Wolfer, solar rotation, 83, 147

Woods, eclipses of S Velorum, 314

Wright, orbit of η Aquilæ, 322; spectrum of Nova Sagittarii, 385; of Nova Aquilæ, 386

Yendell, orbit plane of Algol, 303; light-change of d Serpentis, 335

Young, prominence photography, 18; spectroscopic measurement of the sun’s rotation, 19, 283; observation of reversing layer, 19, 44; description of flash photograph, 45; thermal variations of the sun, 67; structure of sun-spots, 77; their spectra, 88, 91, 93, 94; helium absorption in, 94; calcium in the sun, 114; chromospheric spectrum, 119; mode of solar rotation, 149; eruptions in the sun, 165

Zeeman effect, described, 6; possibly present in spectrum of Mira, 224

THE END

Printed by R. & R. CLARK, LIMITED, Edinburgh

-----

Footnote 1:

Fowler, Introduction to Novum Organum, p. 38; Descriptio Globi Intellectualis, chaps. v., vii.; De Augmentis, iii. 4.

Footnote 2:

Astrophysical Journal, vol. vi. p. 273.

Footnote 3:

The Observatory, vol. xx. p. 144.

Footnote 4:

The indications of this beautiful instrument, which depend upon the changes of electrical resistance in a strip of platinum, produced by differences of temperature, are believed to be reliable to one-hundred-millionth of a degree centigrade. Langley, Phil. Mag. July 1901, p. 123.

Footnote 5:

Proc. Royal Society, vol. xlvi. p. 134.

Footnote 6:

Journal de Physique, t. x. p. 16.

Footnote 7:

Cortie, Astronomy and Astrophysics, vol. xi. p. 399.

Footnote 8:

Trans. Royal Society of Edinburgh, vol. xxxvi. part i.

Footnote 9:

Phil. Mag. August 1892.

Footnote 10:

A micron = one-thousandth of a millimetre.

Footnote 11:

Annals of the Smithsonian Astrophysical Observatory, vol. i. p. 170.

Footnote 12:

Trans. Swedish Acad. of Sciences, 1889; Journ. de Physique, t. x. p. 141.

Footnote 13:

Phil. Trans. vol. clxxvii. p. 457.

Footnote 14:

Ibid. p. 462.

Footnote 15:

Wiedemann’s Annalen, Bd. xlvii. p. 208 (1892). See also E. P. Lewis’s important investigations of “The Wave-Lengths of Infra-Red Lines,” Astr. Ph. Journal, vol. ii. p. 1.

Footnote 16:

Published in its enlarged form in 1889.

Footnote 17:

Die Spectralanalyse der Gestirne, p. 177.

Footnote 18:

Astrophysical Journal, vol. ix. p. 214.

Footnote 19:

Astr. and Astrophysics, vol. xiii. p. 506.

Footnote 20:

Comptes Rendus, t. cxi. p. 431.

Footnote 21:

Astr. and Astrophysics, vol. xiii. p. 216.

Footnote 22:

Runge and Paschen, Wiedemann’s Annalen, Bd. lxi. p. 641 (1897).

Footnote 23:

Astroph. Journ. vol. iv. p. 317, vol. vi. p. 426. A second triplet is also possibly present, but it is less obvious than the first.

Footnote 24:

Astroph. Journ. vol. vi. p. 101.

Footnote 25:

Proceedings Royal Society, vol. xxvii. p. 308.

Footnote 26:

American Journ. of Science, vol. xxxiv. p. 348.

Footnote 27:

Kayser and Runge, Wied. Annalen, Bd. xxxviii. p. 80; Crew and Basquin, Astroph. Journ. vol. ii. p. 103.

Footnote 28:

Hartley, Proc. Royal Society, vol. lv. p. 348.

Footnote 29:

Astroph. Journ. vol. iv. p. 232.

Footnote 30:

Ibid. vol. v. p. 194.

Footnote 31:

Moissan, Le Four Électrique, pp. 257, 261.

Footnote 32:

Journal Chemical Society, 1887, vol. lv. p. 284.

Footnote 33:

Cleve, Trans. Chem. Society, 1895, p. 470.

Footnote 34:

What is Electricity? p. 299.

Footnote 35:

Amer. Journ. of Science, vol. i. p. 331, 4th series.

Footnote 36:

Astroph. Journ. vol. i. p. 89.

Footnote 37:

Ibid. vol. x. p. 161.

Footnote 38:

R. A. Porter, Astroph. Journ. vol. xv. p. 281.

Footnote 39:

Fowler, Knowledge, vol. xxiii. p. 11.

Footnote 40:

Astr. and Astrophysics, vol. xi. p. 79.

Footnote 41:

Cortie, ibid. p. 591.

Footnote 42:

Astroph. Journ. vol. iii. p. 106.

Footnote 43:

Astroph. Journ. vol. iii. p. 157.

Footnote 44:

Ibid. pp. 92, 93.

Footnote 45:

Astroph. Journ. vols. iii. p. 114, iv. p. 175, vi. p. 169.

Footnote 46:

Ibid. vol. vi. p. 225.

Footnote 47:

Astroph. Journ. vol. xi. p. 240.

Footnote 48:

Ibid. vol. iii. p. 100.

Footnote 49:

Astroph. Journ. vol. iii. pp. 102, 103 (Jewell), p. 158 (Hale).

Footnote 50:

Jewell, Astroph. Journ. vol. xi. p. 236.

Footnote 51:

Memoirs Royal Astr. Society, vol. xli. pp. 339, 434 (Ranyard).

Footnote 52:

Ibid. p. 115.

Footnote 53:

The Sun, ed. 1897, p. 358.

Footnote 54:

Only the more refrangible parts of the portrayed spectra have been reproduced. The complete images reach down to λ 6000 in the orange.

Footnote 55:

Phil. Trans. vol. cxcvii. A. p. 402.

Footnote 56:

S. A. Mitchell, Astroph. Journ. vol. xv. p. 118.

Footnote 57:

Monthly Notices, vol. lviii. p. 300 (Evershed).

Footnote 58:

Hale, Astroph. Journ. vol. iii. p. 160.

Footnote 59:

Proc. Royal Society, 17th Jan. 1901.

Footnote 60:

Knowledge, vol. ix. p. 50.

Footnote 61:

W. E. Wilson, Proc. Royal Soc. 12th Dec. 1901.

Footnote 62:

Ibid. vol. xxx. p. 93.

Footnote 63:

Sitzungsberichte Berlin Acad. der Wiss. March 1894.

Footnote 64:

Comptes Rendus, 9th July 1894.

Footnote 65:

Publicationen des Haynaldschen Observatoriums, Heft vi. p. 15, 1892.

Footnote 66:

See Knowledge, vol. ix. p. 49 (E. W. Maunder).

Footnote 67:

The third hydrogen line (Hγ), often called “G,” is adjacent to the band at λ 431 named G by Fraunhofer.

Footnote 68:

Wiedemann’s Annalen, Bd. xxv. p. 80.

Footnote 69:

Phil. Mag. vol. xli. p. 294 (1871).

Footnote 70:

Trans. Royal Soc. of Edinburgh, vol. xxxii.

Footnote 71:

Journ. Chem. Society, vol. xliii. p. 390.

Footnote 72:

Journ. de Physique, t. v. p. 341 (1886).

Footnote 73:

Phil. Trans. vol. clxxiv. p. 187.

Footnote 74:

Nature, vol. lv. p. 200.

Footnote 75:

Phil. Mag. vol. xxix. p. 331; Wied. Ann. Bd. lii. p. 119.

Footnote 76:

Ibid. Bd. lxi. p. 641.

Footnote 77:

Berlin Abhandl. 1890

Footnote 78:

Phil. Mag. vol. xxx. p. 33 (1890).

Footnote 79:

Astroph. Journ. vol. v. p. 209.

Footnote 80:

Ibid. vol. v. p. 92; Kayser, ibid. pp. 95, 243.

Footnote 81:

Rydberg, ibid. vol. vi. p. 233.

Footnote 82:

Dewar, Trans. Chem. Society, 1898, p. 535.

Footnote 83:

Astroph. Journ. vol. vii. p. 25. The idea seems to have been anticipated by Waterston in 1845. E. Rogovsky, ibid. vol. xiv. p. 251, note.

Footnote 84:

S. R. Cook, ibid. vol. xi. p. 36; but cf. Stoney, ibid. pp. 251, 357.

Footnote 85:

Rowland observed in his photographs some “thin haze,” which he regarded as possibly due to diffuse absorption by four ultra-violet hydrogen lines, but the connection is very doubtful. Huggins, Atlas of Stellar Spectra, p. 150.

Footnote 86:

Chemical News, 29th March 1895; Nature, 19th December 1901.

Footnote 87:

Nature, 6th June 1895.

Footnote 88:

Their wave-lengths are λλ 7066, 5016, 4472, and 4026.

Footnote 89:

Lockyer, Nature, 3rd October 1895.

Footnote 90:

Runge and Paschen, Nature, 26th Sept. 1895; Sitzungsberichte Berlin Akad. 20th June 1895; Astroph. Journ. vol. iii. p. 4; Maunder, Knowledge, vol. xix. p. 285.

Footnote 91:

Ramsay and Collie, Proc. Royal Society, vol. lx. p. 56.

Footnote 92:

Ibid. vol. lix. p. 222.

Footnote 93:

See Nature, 17th and 24th May 1900 (Cook and Johnstone Stoney).

Footnote 94:

Fifth Robert Boyle Lecture, 2nd June 1895.

Footnote 95:

Ramsay, Collie, and Travers, Journ. Chem. Society, 1895, p. 697.

Footnote 96:

Collie and Ramsay, Proc. Royal Society, vol. lix. p. 264.

Footnote 97:

The Sun, p. 110, edit. 1897.

Footnote 98:

Proc. Royal Society, vol. xvi. p. 29.

Footnote 99:

Scheiner, Strahlung und Temperatur der Sonne, p. 27.

Footnote 100:

Proc. Royal Society, vol. lviii.

Footnote 101:

Young, The Sun, p. 302.

Footnote 102:

Phil. Trans. vol. clxxxv. p. 396.

Footnote 103:

Phil. Mag. vol. viii. pp. 324, 550.

Footnote 104:

Wiedemann’s Annalen, Bd. xxxix. p. 309.

Footnote 105:

Proc. Royal Society, 12th December 1901.

Footnote 106:

Comptes Rendus, t. cxiv. p. 737, 1892.

Footnote 107:

Journ. de Physique, t. vi. p. 474, 1887.

Footnote 108:

Wied. Ann. Bd. liii. p. 284, 1894.

Footnote 109:

Astroph. Journ. vols. ii. p. 202, x. p. 40, xi. p. 288.

Footnote 110:

Ibid. vol. ii. p. 57.

Footnote 111:

F. W. Very, Astroph. Journ. vol. ii. p. 317.

Footnote 112:

Ibid. vol. iv. p. 44.

Footnote 113:

The “solar constant” is the number of units of heat per unit of area which would be received in unit of time by the earth’s surface if its atmosphere were removed. The most approved value is three (small) calories per square centimetre per minute, a “small” calorie being the quantity of heat requisite to raise one gramme of water one degree centigrade.

Footnote 114:

Hence Savélieff’s experiments, according to which the solar energy progressively augmented with the increase in the number of spots in the years 1890, 1891, and 1892, are suggestive rather than conclusive (Comptes Rendus, t. cxviii. p. 62, and Astroph. Journ. vol. xiii. p. 346).

Footnote 115:

Astroph. Journ. vol. vii. pp. 255, 264.

Footnote 116:

Proc. Royal Irish Acad. vol. ii. p. 299, third series.

Footnote 117:

Monatsberichte, Berlin, 1877, p. 104.

Footnote 118:

Astroph. Journ. vol. i. p. 261.

Footnote 119:

Proceedings Amer. Acad. of Sciences, 1880; Amer. Journ. of Science, vol. xxi. p. 41, 1881.

Footnote 120:

Strahlung und Temperatur der Sonne, p. 49.

Footnote 121:

Vol. i. p. 74, 1902.

Footnote 122:

Astr. Nach. Nos. 3330, 3410.

Footnote 123:

Rev. W. Sidgreaves, Astr. and Astrophysics, vol. xi. p. 212.

Footnote 124:

Astroph. Journ. vol. v. p. 250; Observatory, vol. xxi. p. 404.

Footnote 125:

Memoirs Royal Astr. Society, vol. xli. p. 8 (Ranyard).

Footnote 126:

Memoirs Brit. Astr. Ass. vol. v. p. 84.

Footnote 127:

A. J. S. Adams, Journ. Brit. Astr. Ass. vol. iv. p. 203; E. Brown, ibid. p. 300.

Footnote 128:

The Sun, p. 125.

Footnote 129:

Il Sole, p. 62, ed. 1884.

Footnote 130:

Suffusions of dark red matter were observed in the umbræ of a multiple spot by E. S. Martin, 17th September 1893, Popular Astronomy, vol. i. p. 91.

Footnote 131:

Memoirs Brit. Astr. Ass. vol. iv. p. 92.

Footnote 132:

Maunder, Observatory, vol. xxi. p. 403.

Footnote 133:

Ibid. p. 402, vol. xxiii. p. 233.

Footnote 134:

Monthly Notices, vol. lv. p. 73.

Footnote 135:

Ibid. vol. lviii. p. 91.

Footnote 136:

Old and New Astronomy, p. 382.

Footnote 137:

Knowledge, vol. xxi. p. 89.

Footnote 138:

Astroph. Journ. vol. vi. p. 91.

Footnote 139:

Monthly Notices, vol. lv. p. 282.

Footnote 140:

Astroph. Journ. vol. vi. p. 366.

Footnote 141:

Astr. and Astrophysics, vol. xi. p. 734; Astroph. Journ. vol. iv. p. 201. Cf. J. Halm, Annals Edin. Observatory, vol. i. p. 145.

Footnote 142:

Monthly Notices, vol. lv. p. 458.

Footnote 143:

Ibid. vol. xxxvii. p. 5.

Footnote 144:

Astr. and Astrophysics, vol. xii. p. 739.

Footnote 145:

Frost, Astroph. Journ. vol. iv. p. 200.

Footnote 146:

Journ. Brit. Astr. Ass. vol. vii. p. 121.

Footnote 147:

Maunder, Knowledge, vol. xvii. p. 198.

Footnote 148:

Observatory, vol. xxiii. p. 230.

Footnote 149:

Knowledge, vol. xvii. p. 199.

Footnote 150:

Cortie, Observatory, vol. xxiii. p. 230.

Footnote 151:

Recherches sur la Rotation du Soleil, p. 12.

Footnote 152:

Young, The Sun, p. 132.

Footnote 153:

Astr. and Astrophysics, vol. xi. p. 242.

Footnote 154:

Proc. Royal Society, vol. xv. p. 257.

Footnote 155:

Chemistry of the Sun, p. 324.

Footnote 156:

Ibid. p. 319.

Footnote 157:

Memoirs Royal Astr. Society, vol. l. p. 50.

Footnote 158:

Monthly Notices, vol. lviii. p. 373.

Footnote 159:

Frost-Scheiner, Astronomical Spectroscopy, p. 177; J. S. Ames, Astroph. Journ. vol. i. p. 89; Hartley, Proc. Royal Society, vol. lvi. p. 192.

Footnote 160:

Monthly Notices, vol. xlvii. p. 19.

Footnote 161:

Nature, 12th Dec. 1872.

Footnote 162:

Astroph. Journ. vol. v. p. 248.

Footnote 163:

Gases glowing electrically in vacuum tubes were found by M. Cantor incapable of absorption. But the results of further experiments must be awaited before conclusions in so delicate a matter can be availed of to elucidate the state of helium in the sun.

Footnote 164:

Nature, 12th Sept. 1895; The Sun, p. 134.

Footnote 165:

Monthly Notices, vol. lii. p. 424.

Footnote 166:

Journ. Brit. Astr. Ass. vol. ix. p. 253.

Footnote 167:

Ibid. vol. vii. p. 191.

Footnote 168:

Astr. and Astrophysics, vol. xi. p. 313.

Footnote 169:

Mascari, Astroph. Journ. vol. vi. p. 372.

Footnote 170:

Astr. and Astrophysics, vol. xi. pp. 159, 414.

Footnote 171:

Comptes Rendus, 8th Feb. 1892; Knowledge, vol. xvi. p. 230.

Footnote 172:

Deslandres, L’Astronomie, Dec. 1894.

Footnote 173:

Deslandres, Comptes Rendus, t. cxiv. No. ii.; Journ. Brit. Astr. Ass. vol. ii. p. 237.

Footnote 174:

Evershed, Astr. and Astrophysics, vol. xi. p. 240.

Footnote 175:

Amer. Journ. of Science, vol. xi. p. 169 (1876).

Footnote 176:

Publicat. Haynald Observatory, Bd. vi. p. 40.

Footnote 177:

Comptes Rendus, 25th Jan. 1897.

Footnote 178:

Astr. and Astrophysics, vol. xiii. p. 124.

Footnote 179:

Astroph. Journ. vol. i. p. 212.

Footnote 180:

Comptes Rendus, t. ci. pp. 50, 475.

Footnote 181:

Trouvelot, Bull. Astr. t. iii. p. 21.

Footnote 182:

Fényi, Astr. and Astrophysics, vol. xii. p. 38.

Footnote 183:

Deslandres, indeed, observed velocities to become, as a rule, accelerated in the upper sections of prominences (Éclipse du 16 Avril, 1893, p. 60); but this need not imply that they spring up in a perfect vacuum.

Footnote 184:

Astr. and Astrophysics, vol. xi. p. 63.

Footnote 185:

H. H. Turner, ibid. p. 67.

Footnote 186:

Brester, Théorie du Soleil, p. 54.

Footnote 187:

Hale, Astroph. Journ. vol. iii. p. 377.

Footnote 188:

Phil. Trans. vol. clxxx. p. 345.

Footnote 189:

L’Astronomie, t. xii. p. 11.

Footnote 190:

Lick Reports on Total Eclipse of 1st January 1889, p. 204.

Footnote 191:

Memoirs Royal Astr. Society, vol. xli. p. 519 (Ranyard).

Footnote 192:

Phil. Trans. vol. cxc. p. 204 (Wesley).

Footnote 193:

Bull. de l’Acad. Imp. des Sciences, Mars 1897, p. 253.

Footnote 194:

Frost-Scheiner, Astronomical Spectroscopy, p. 189.

Footnote 195:

Proc. Royal Society, vol. lviii. p. 255.

Footnote 196:

Some American photographs taken during the eclipse of 28th May 1900 (Astroph. Journ. vol. xii. p. 63) show a brightening upward from the limb, as if through increased rarefaction, of a few lines belonging to green helium. This behaviour runs in the direction indicated by vacuum-tube experience.

Footnote 197:

See ante, p. 60.

Footnote 198:

Proc. Royal Society, vol. lxvii. p. 467.

Footnote 199:

The Chemistry of the Sun, p. 194.

Footnote 200:

Proc. Royal Society, vol. lxi. p. 433. Besides H and K, echoes of them survive in a pair situated so high in the ultra-violet that they can only be photographed with a specially adapted apparatus. Their wave-lengths are λ 3179 and λ 3159. They may or may not be chromospheric lines. The records so far obtained do not extend to their remote position.

Footnote 201:

Bulletin of the Yerkes Observatory, No. 4, 1897.

Footnote 202:

Observations de l’Éclipse Totale du Soleil du 16 Avril, 1893, p. 64.

Footnote 203:

Hale, Astroph. Journ. vol. v. p. 225.

Footnote 204:

Evershed, Nature, 9th Sept. 1897.

Footnote 205:

Astr. and Astrophysics, vol. xi. p. 738.

Footnote 206:

Ibid. p. 430.

Footnote 207:

The Indian Eclipse, p. 70.

Footnote 208:

Astroph. Journ. vol. xi. p. 243.

Footnote 209:

Ibid. p. 165.

Footnote 210:

Ibid. vol. vi. p. 412.

Footnote 211:

Ibid. vol. x. pp. 112, 287.

Footnote 212:

Astr. and Astrophysics, vol. xi. p. 66.

Footnote 213:

Astr. and Astrophysics, vol. xi. p. 821.

Footnote 214:

Proc. Royal Society, vol. lxviii. p. 396.

Footnote 215:

See a valuable discussion by Hale, Astroph. Journ. vol. iii. pp. 374–387.

Footnote 216:

Phil. Trans. vol. cxcvii. A, p. 399.

Footnote 217:

Astr. and Astrophysics, vol. xi. p. 431; Comptes Rendus, 17th Aug. 1891 (Fényi).

Footnote 218:

Astr. and Astrophysics, vol. xiii. p. 119.

Footnote 219:

Comptes Rendus, 25th July 1892; Knowledge, vol. xvi. p. 146 (A. M. Clerke).

Footnote 220:

The New Astronomy, p. 40.

Footnote 221:

Memoirs Royal Astr. Society, vol. xli. p. 563 (Ranyard).

Footnote 222:

Publications Pacific Society, vol. ii. p. 68.

Footnote 223:

Memoirs Royal Astr. Society, vol. xli. p. 656.

Footnote 224:

Ranyard, ibid. p. 652.

Footnote 225:

Ibid. p. 589 (Pope Hennessy).

Footnote 226:

Perrine, Lick Bulletin, No. 9.

Footnote 227:

Ranyard, Memoirs Royal Astr. Society, vol. xli. p. 687.

Footnote 228:

Lick Reports, p. 193.

Footnote 229:

Phil. Trans. vol. cxc. p. 204.

Footnote 230:

Knowledge, vol. xii. p. 145, 1889.

Footnote 231:

Report on the Eclipse, p. 96.

Footnote 232:

Ibid. p. 100; Observatory, vol. xvii. p. 350.

Footnote 233:

Mémoires Acad. de St. Pétersbourg, t. iv. p. 38, 1862.

Footnote 234:

Memoirs Royal Astr. Society, vol. xli. p. 602.

Footnote 235:

The New Astronomy, p. 55.

Footnote 236:

Memoirs Royal Astr. Society, vol. xlvi. p. 238.

Footnote 237:

Young, The Sun, p. 264.

Footnote 238:

Bull. de l’Acad. de St. Pétersbourg, t. vi. p. 286.

Footnote 239:

Atti dell’ Accad. dei Lincei, 1889, p. 763.

Footnote 240:

Schaeberle, Report on the Eclipse of 16th April 1893, pp. 92–98.

Footnote 241:

Bull. de l’Acad. de St. Pétersbourg, t. vi. p. 253, 1897.

Footnote 242:

Nature, vol. lix. p. 529.

Footnote 243:

Astroph. Journ. vol. x. p. 190.

Footnote 244:

S. J. Brown, Astroph. Journ. vol. xii. p. 63.

Footnote 245:

Ibid. p. 73.

Footnote 246:

Frost-Scheiner, Astr. Spectroscopy, p. 192; Comptes Rendus, t. cxvii. p. 25.

Footnote 247:

Astroph. Journ. vol. xi. p. 232.

Footnote 248:

Schuster, Monthly Notices, vol. xl. p. 35.

Footnote 249:

Observatory, vol. xxi. p. 157.

Footnote 250:

Burnham and Schaeberle, Report on Eclipse of December 1889, p. 38.

Footnote 251:

Bull. de l’Acad. de St. Pétersbourg, t. iv. p. 275.

Footnote 252:

Popular Astronomy, vol. viii. p. 369.

Footnote 253:

The Indian Eclipse, p. 114.

Footnote 254:

Ibid. p. 118.

Footnote 255:

Wesley, Knowledge, Oct. 1900, p. 227.

Footnote 256:

Maunder, Knowledge, vol. xxi. p. 109. Cf. the visual observations of Seagrave in 1900, Astroph. Journ. vol. xii. p. 99.

Footnote 257:

Hale, Astr. and Astrophysics, vol. xiii. p. 662.

Footnote 258:

Observations de l’Éclipse du 16th Avril 1893, p. 43.

Footnote 259:

The Observatory, vol. xxi. p. 188.

Footnote 260:

Astroph. Journ. vol. x. p. 186.

Footnote 261:

Loc. cit. p. 50.

Footnote 262:

Total Solar Eclipse, Dec. 1889, p. 47.

Footnote 263:

The Indian Eclipse, p. 121.

Footnote 264:

Popular Astronomy, p. 260 (edit. of 1878).

Footnote 265:

Astroph. Journ. vol. xii. p 25.

Footnote 266:

Proc. Royal Society, vol. xxxix. p. 108.

Footnote 267:

Deslandres, loc. cit. p. 62.

Footnote 268:

The Solar Corona discussed by Spherical Harmonics, 1889.

Footnote 269:

Public. Pacific Society, vol. iii. p. 216.

Footnote 270:

Astr. and Astrophysics, vol. xii. p. 804.

Footnote 271:

Magnetic Fields of Force, p. 73 (1897).

Footnote 272:

Reports on Eclipse of 1st January, 1889, p. 10.

Footnote 273:

Bull. de l’Acad. des Sciences de St. Pétersbourg, t. vi. March 1897.

Footnote 274:

Astr. and Astrophysics, vol. xi. p. 483.

Footnote 275:

Amer. Journ. of Science, vol. xi. p. 253, 1901.

Footnote 276:

Annalen der Physik, 1900, p. 462; quoted by G. F. Fitzgerald, Nature, vol. lxii. p. 7.

Footnote 277:

Comptes Rendus, t. cxxx. p. 1691; Nature, 5th July 1900.

Footnote 278:

Bigelow, Astr. and Astrophysics, vol. xii. p. 823.

Footnote 279:

Astr. and Astrophysics, vol. xii. p. 825.

Footnote 280:

History of Astronomy (A. M. Clerke), 4th edit. p. 202.

Footnote 281:

Recherches sur la Rotation du Soleil, p. 55.

Footnote 282:

Potsdam Publ. Bd. iv. pt. ii.; Astr. Nach. Nos. 3000, 3153, 3287.

Footnote 283:

Astr. and Astrophysics, vol. xii. p. 632.

Footnote 284:

Astr. Nach. Nos. 3275, 3344.

Footnote 285:

Monthly Notices, vol. lv. No. 1; Astroph. Journ. vol. xiv. p. 317.

Footnote 286:

See ante, p. 98.

Footnote 287:

Vierteljahrsschrift Naturforsch. Ges. in Zürich, Bd. xli. 1896.

Footnote 288:

Astroph. Journ. vol. iv. p. 138.

Footnote 289:

Bull. de l’Acad. de St. Pétersbourg, t. vi. No. 3, p. 293.

Footnote 290:

Astr. Journ. No. 416; Astroph. Journ. vol. iv. p. 101.

Footnote 291:

Ibid. vol. v. p. 37.

Footnote 292:

Astr. Nach. No. 3039; Astroph. Journ. vol. iii. p. 247.

Footnote 293:

Memoirs Royal Astr. Society, vol. li. p. 123.

Footnote 294:

Astroph. Journ. vol. iii. p. 248.

Footnote 295:

Cf. Halm, Annals Edin. Observatory, vol. i. p. 99, 1902.

Footnote 296:

Clerke, Hist. of Astr. pp. 148, 149, 4th ed.; Spoerer, Potsdam Publ. Bd. x. part i. 1894.

Footnote 297:

Knowledge, vol. xv. p. 131.

Footnote 298:

Fényi, Publ. Haynald Observ. Bd. vi. p. 41.

Footnote 299:

Mascari, Astroph. Journ. vol. ii. p. 119; Evershed, Astr. and Astroph. vol. xi. p. 426.

Footnote 300:

Mascari, Astroph. Journ. vol. vi. p. 371.

Footnote 301:

Proc. Royal Society, vol. lxiii. p. 64; Monthly Notices, vol. lx. p. 142.

Footnote 302:

Knowledge, vol. xvii. p. 175.

Footnote 303:

Ibid. p. 206 (A. M. Clerke).

Footnote 304:

Trans. Astr. Society of Toronto, 1897, p. 80.

Footnote 305:

Observatory, vol. xiv. p. 328.

Footnote 306:

Ibid. vol. xv. p. 143.

Footnote 307:

Maunder, Knowledge, vol. xv. p. 89.

Footnote 308:

Ibid. p. 93.

Footnote 309:

Astr. and Astrophysics, vol. xi. p. 437.

Footnote 310:

Ibid. p. 925.

Footnote 311:

Astr. and Astrophysics, vol. xii. p. 717.

Footnote 312:

Report Brit. Ass. 1892, p. 634.

Footnote 313:

Astr. Nach. Nos. 2836, 2837.

Footnote 314:

Nature, vol. lxi. p. 445; vol. lxii. p. 460; Astr. Nach. No. 3619.

Footnote 315:

Wiedemann’s Annalen, Bd. lix. p. 782, 1896.

Footnote 316:

Bigelow, Report on Solar and Terrestrial Magnetism, p. 15.

Footnote 317:

Astroph. Journ. vol. iii. p. 112.

Footnote 318:

Astr. and Astrophysics, vol. xii. p. 740.

Footnote 319:

Astr. and Astrophysics, vol. xiii. p. 278.

Footnote 320:

The Sun, p. 187.

Footnote 321:

Astr. and Astrophysics, vol. xii. p. 833.

Footnote 322:

Die Strahlenbrechung auf der Sonne, Stuttgart, 1891.

Footnote 323:

Monatsberichte, Berlin, 1860, p. 405.

Footnote 324:

Knopf, Astr. Nach. No. 3199.

Footnote 325:

Sirius, 1893, p. 176.

Footnote 326:

Astr. Nach. No. 3187.

Footnote 327:

Frost, Astroph. Journ. vol. iv. p. 196.

Footnote 328:

Ibid. vol. xii. p. 185.

Footnote 329:

Monatsberichte, Berlin, 24th October 1895.

Footnote 330:

Harvard Annals, vol. xxviii. part i. 1897.

Footnote 331:

S. A. Mitchell, Astroph. Journ. vol. x. p. 32.

Footnote 332:

Astr. and Astrophysics, vol. xiii. p. 661.

Footnote 333:

This “short title” was first applied to them by Sir Norman Lockyer. See Nature, 18th May 1899.

Footnote 334:

Potsdam Publicationen, No. 14, p. 26, 1884.

Footnote 335:

Die Spectralanalyse der Gestirne, p. 320.

Footnote 336:

Dunér, Astroph. Journ. vol. ix. p. 131.

Footnote 337:

Astroph. Journ. vol. x. p. 108.

Footnote 338:

Astroph. Journ. vol. viii. p. 233.

Footnote 339:

Campbell, Astroph. Journ. vol. ii. p. 181.

Footnote 340:

Harvard Annals, vol. xxviii. pp. 49, 93, 100, 142.

Footnote 341:

Monthly Notices, vol. lix. p. 507.

Footnote 342:

Comptes Rendus, t. lxxiv. p. 516.

Footnote 343:

Pickering, Astroph. Journ. vol. vi. p. 459.

Footnote 344:

Astr. Nach. No. 3025.

Footnote 345:

Campbell, Astr. and Astrophysics, vol. xiii. p. 474.

Footnote 346:

Phil. Trans. vol. cxci. p. 129.

Footnote 347:

Maury, Harvard Annals, vol. xxviii. p. 15.

Footnote 348:

Abhandl. der kön. Sächs. Gesellschaft, Bd. xv. Th. 1.

Footnote 349:

One taken 1st February is shown in Knowledge, vol. xix. p. 109.

Footnote 350:

Astr. and Astrophysics, vol. xiii. p. 178.

Footnote 351:

Knowledge, vol. xix. p. 39.

Footnote 352:

Harvard Annals, vol. xxxii. p. 66.

Footnote 353:

ε Orionis = N.G.C. 1990.

Footnote 354:

Barnard, Pop. Astr. Sept. 1897, p. 232.

Footnote 355:

Spectra of Southern Stars, p. 11.

Footnote 356:

Proc. Royal Society, 27th April 1899.

Footnote 357:

Astr. and Astrophysics, vol. xiii. p. 491.

Footnote 358:

Astr. Nach. Nos. 3565, 3583. Bellatrix was one of McClean’s original oxygen stars.

Footnote 359:

Nature, vol. lxi. p. 263.

Footnote 360:

Astroph. Journ. vol. xi. p. 262.

Footnote 361:

Ibid. vol. x. p. 31 (Mitchell).

Footnote 362:

Atlas of Stellar Spectra, p. 152.

Footnote 363:

Scheiner, Sitzungsberichte, Berlin, 13th February 1890.

Footnote 364:

Nature, vol. lix. p. 342.

Footnote 365:

Hartley, Astroph. Journ. vol. x. p. 164.

Footnote 366:

Astroph. Journ. vol. ix. p. 267.

Footnote 367:

Nature, 16th March 1899.

Footnote 368:

Cf. A. Cotton on “Kirchhoff’s law,” Astroph. Journ. vol. ix. p. 244, note.

Footnote 369:

Huggins, Atlas of Spectra, p. 148.

Footnote 370:

Astr. Nach. No. 3025.

Footnote 371:

Spectra of Southern Stars, p. 3.

Footnote 372:

A. C. Maury, Harvard Annals, vol. xxviii. p. 24.

Footnote 373:

Frost-Scheiner, Astronomical Spectroscopy, p. 243.

Footnote 374:

Proc. Royal Society, vol. xlviii. p. 216.

Footnote 375:

The Sun’s Place in Nature, p. 305.

Footnote 376:

Sitzungsberichte, Berlin, March 1894.

Footnote 377:

Astr. and Astrophysics, vol. xiii. p. 660.

Footnote 378:

Harvard Annals, vol. xxviii. p. 27.

Footnote 379:

A. C. Maury, Harvard Annals, vol. xxviii. p. 30.

Footnote 380:

Astr. and Astrophysics, vol. xii. p. 720.

Footnote 381:

Phil. Trans. vol. cxci. plate 6.

Footnote 382:

Fowler, Knowledge, vol. xx. p. 78.

Footnote 383:

Harvard Annals, vol. xxviii. p. 39.

Footnote 384:

Astronomical Spectroscopy (Frost), p. 266.

Footnote 385:

Harvard Annals, vol. xxviii. p. 40.

Footnote 386:

Dunér, Sur les Étoiles à Spectres de la Troisième Classe, p. 9.

Footnote 387:

Thiele, Astroph. Journ. vol. viii. p. 1.

Footnote 388:

Harvard Annals, vol. xxviii. p. 42.

Footnote 389:

Frost-Scheiner, Astr. Spectroscopy, p. 308.

Footnote 390:

Astroph. Journ. vol. vi. p. 423.

Footnote 391:

Potsdam Publicationen, No. 14, p. 22.

Footnote 392:

Spectra of Southern Stars, Plate iv.

Footnote 393:

Astroph. Journ. vol. vi. p. 424.

Footnote 394:

The star was named Ant-Ares (“like Mars”) because of its resemblance to the planet in colour.

Footnote 395:

Monthly Notices, vol. lii. p. 154.

Footnote 396:

Monthly Notices, vol. lviii. p. 443.

Footnote 397:

Astroph. Journ. vol. x. p. 93.

Footnote 398:

Espin, loc. cit.

Footnote 399:

Astroph. Journ. vol. ix. p. 132.

Footnote 400:

Astroph. Journ. vols. viii. p. 237, ix. p. 271, x. p. 87.

Footnote 401:

Hale, First Annual Report, p. 7. Spectrographs of 152 Schjellerup, taken by McClean with two hours’ exposure, were described by him in 1897 as showing a multitude of dark lines.—Monthly Notices, vol. lvii. p. 8.

Footnote 402:

Astroph. Journ. vol. viii. p. 239.

Footnote 403:

Sugli Spettri Prismatici delle Stelle Fisse, Mem. ii. 1869.

Footnote 404:

Sur les Étoiles à Spectres de la Troisième Classe, pp. 10, 82.

Footnote 405:

Astroph. Journ. vol. ix. p. 119.

Footnote 406:

Ibid. vol. x. p. 110.

Footnote 407:

Astroph. Journ. vol. x. p. 112.

Footnote 408:

First Annual Report, p. 8.

Footnote 409:

Sur les Étoiles, p. 45.

Footnote 410:

Astroph. Journ. vol. ix. p. 274.

Footnote 411:

They are catalogued in the southern zones of the Bonn Durchmusterung as −10°5057 and −10°513.

Footnote 412:

Hale, Astroph. Journ. vol. viii. p. 239; Espin, ibid. vol. x. p. 170.

Footnote 413:

Sidgreaves, Monthly Notices, vol. lviii. p. 345.

Footnote 414:

Sitzungsberichte, Berlin, 26th March 1896.

Footnote 415:

Monthly Notices. vol. lviii. p. 344.

Footnote 416:

Astroph. Journ. vol. ix. p. 31; Observatory, vol. xxii. p. 152.

Footnote 417:

Krüger, Astroph. Journ. vol. ii. pp. 151, 158.

Footnote 418:

Keeler, Lick Publ. vol. iii. p. 225.

Footnote 419:

Espin, Astr. Nach. No. 2859.

Footnote 420:

Maunder believed it to be of fourth type, 1st Oct. 1888. Monthly Notices, vol. xlix. p. 303.

Footnote 421:

Astr. Nach. No. 3765.

Footnote 422:

Astroph. Journ. vol. viii. p. 233.

Footnote 423:

Astroph. Journ. vol. ii. p. 178.

Footnote 424:

Runge, Astr. Nach. No. 3471.

Footnote 425:

Professor Frost’s conjecture that such stars may possess atmospheres preferentially absorbent of the shorter radiations did not seem to himself plausible enough for publication. Astroph. Journ. vol. ii. p. 182. A similar explanation, however, has lately been recommended by Dr. Kayser. Ibid. vol. xiv. p. 313.

Footnote 426:

Astroph. Journ. vol. ii. p. 181.

Footnote 427:

Evidently analogous is Hale’s result that the lines first reversed in metallic spectra are the most refrangible. Astroph. Journ. vol. xv. p. 227.

Footnote 428:

A. C. Maury, Harvard Annals, vol. xxviii. p. 104.

Footnote 429:

Keeler, Astr. and Astrophysics, vol. xiii. p. 486. The helium line, λ 4472, is specially described. It is bright in the Orion nebula, dark in all Orion stars.

Footnote 430:

Proc. Royal Society, vol. xlvi. p. 41.

Footnote 431:

Campbell, Astr. and Astroph. vol. xiii. p. 397.

Footnote 432:

Comptes Rendus, 11th Oct. 1897; Astroph. Journ. vol. vi. p. 322; Atlas of Spectra, p. 138.

Footnote 433:

A. C. Maury, Harvard Annals, vol. xxviii. p. 104.

Footnote 434:

Astroph. Journ. vol. ii. p. 180.

Footnote 435:

A. C. Maury, loc. cit. pp. 49, 100.

Footnote 436:

Sidgreaves, Monthly Notices, vol. lix. p. 506.

Footnote 437:

O Gyalla Beob. Bd. vii. p. 14. For Keeler’s failure to perceive D-absorption see Publ. Pacific Society, vol. i. p. 80.

Footnote 438:

System of the Stars, p. 70.

Footnote 439:

Bélopolsky, Astr. Nach. No. 3603; Astroph. Journ. vol. x. p. 319.

Footnote 440:

Harvard Annals, vol. xxviii. p. 175.

Footnote 441:

Astr. Nach. No. 2963.

Footnote 442:

Astr. and Astroph. vol. xiii. p. 158.

Footnote 443:

Frost, Astroph. Journ. vol. x. p. 365.

Footnote 444:

A. C. Maury, loc. cit. p. 104.

Footnote 445:

McClean, Proc. Royal Society, vol. lxii. p. 419.

Footnote 446:

Astroph. Journ. vol. iv. p. 369. For a list of analogous objects see Observatory, vol. xxii. p. 54.

Footnote 447:

Observatory, vol. xxii. p. 52.

Footnote 448:

Astr. and Astroph. vol. xiii. p. 467.

Footnote 449:

Astroph. Journ. vol. ii. p. 177.

Footnote 450:

Harvard Annals, vol. xxviii. p. 247.

Footnote 451:

Spectra of Southern Stars, p. 15, Plate xii.

Footnote 452:

Campbell, Astr. and Astroph. vol. xiii. p. 449; Astroph. Journ. vol. ii. p. 178.

Footnote 453:

Publ. Pac. Society, vol. i. p. 81.

Footnote 454:

Hale, Yerkes Observ. Report, ii. p. 6.

Footnote 455:

Potsdam Publ. No. 14, p. 15.

Footnote 456:

Astr. and Astroph. vol. xiii. pp. 460, 468.

Footnote 457:

Campbell, Astr. and Astroph. vol. xiii. pp. 456, 468; Pickering, Astr. Nach. No. 3025; Vogel, Potsdam Publ. No. 14, p. 17; A. J. Cannon, Harvard Annals, vol. xxviii. pp. 147, 248.

Footnote 458:

Pickering, Astr. Nach. No. 2986.

Footnote 459:

Astr. and Astroph. vol. xiii. p. 461.

Footnote 460:

Ibid. vols. xii. p. 913; xiii. p. 461.

Footnote 461:

Astr. Nach. No. 3471.

Footnote 462:

Astroph. Journ. vol. viii. p. 113.

Footnote 463:

Proc. Royal Society, vol. xlix. p. 33.

Footnote 464:

Jewell, Astroph. Journ. vol. iii. p. 99.

Footnote 465:

Astr. Nach. No. 2000.

Footnote 466:

Frost-Scheiner, Astr. Spectroscopy, p. 323.

Footnote 467:

Argelander, Astr. Nach. No. 624.

Footnote 468:

Monthly Notices, vol. li. p. 12; Krüger, Cat. der färbig. Sterne, p. 81.

Footnote 469:

Astr. Nach. No. 3200.

Footnote 470:

Ibid. No. 3633.

Footnote 471:

Monthly Notices, vol. li. p. 12.

Footnote 472:

Cat. der färbig. Sterne, p. 99.

Footnote 473:

Bothkamp Beob. Heft ii. p. 146.

Footnote 474:

Copeland, Monthly Notices, vol. xlvii. p. 92.

Footnote 475:

Astr. Nach. No. 2539.

Footnote 476:

Proc. Royal Society, vol. lvii. p. 174.

Footnote 477:

Monthly Notices, vol. lix. p. 505.

Footnote 478:

Sugli Spettri Prismatici delle Stelle, Mem. ii. 1868.

Footnote 479:

Frost-Scheiner, Astr. Spectroscopy, p. 256.

Footnote 480:

Lockyer, Proc. Royal Society, vol. lvii. p. 173.

Footnote 481:

Publ. Pacific Society, vol. i. p. 80.

Footnote 482:

Astr. Nach. No. 3129.

Footnote 483:

A. C. Maury, Harvard Annals, vol. xxviii. pp. 124, 126.

Footnote 484:

O Gyalla Beob. Bd. vii. p. 14.

Footnote 485:

Harvard College Circular, No. 32; Annals, vol. xxviii. p. 183.

Footnote 486:

Harvard Circular, No. 32.

Footnote 487:

Ibid. No. 21; Annals, vol. xxviii. p. 184.

Footnote 488:

Astroph. Journ. vol. ii. p. 180.

Footnote 489:

Fifty-fifth Harvard Report, p. 10; Harvard Circular, No. 60; Annals, vol. xxviii. pp. 180, 183.

Footnote 490:

Fleming, Monthly Notices, vol. liii. p. 275; Harvard Circular, No. 4.

Footnote 491:

Astroph. Journ. vol. i. p. 411.

Footnote 492:

Harvard Circular, No. 32.

Footnote 493:

Fleming, Astr. Nach. No. 3054; Astr. and Astrophysics, vol. xi. p. 27.

Footnote 494:

Astroph. Journ. vols. x. p. 365; xvi. p. 114.

Footnote 495:

A. C. Maury, Harvard Annals, vol. xxviii. p. 104.

Footnote 496:

Astr. and Astrophysics, vol. xi. pp. 269, 372, 550.

Footnote 497:

Atti dell’ Accad. degli Agiati, t. ii. 1896.

Footnote 498:

Astr. Nach. No. 1099.

Footnote 499:

Krüger, Cat. der färbig. Sterne, p. 9.

Footnote 500:

Known as “64 b Schjellerup” = Krüger 513. See Cat. der färbig. Sterne, p. 33.

Footnote 501:

No. 6803 of the Copenhagen Catalogue = 214 Schjellerup = Krüger 1436.

Footnote 502:

Krüger 504.

Footnote 503:

Binary in slow motion (Innes). Composite spectrum (A. J. Cannon).

Footnote 504:

S.D.M. −10° 513 and S.D.M. −10° 5057 of eighth and seventh magnitudes respectively.

Footnote 505:

Mensuræ Micrometricæ, p. lxxxi.

Footnote 506:

Intellectual Observer, vol. ii. p. 138, 1863.

Footnote 507:

Annales de l’Observatoire de Nice, t. ii.

Footnote 508:

Webb, Celestial Objects, 4th ed., p. 297; Knowledge, vol. xiii. p. 250.

Footnote 509:

Astr. Nach. No. 3023.

Footnote 510:

Journ. Brit. Astr. Ass. vol. v. p. 457.

Footnote 511:

System of the Stars, p. 159.

Footnote 512:

Les Étoiles, p. 690.

Footnote 513:

Webb, Cel. Objects, vol. ii. p. 182.

Footnote 514:

Burnham, Astr. Nach. Nos. 2875, 3114.

Footnote 515:

A. C. Maury, Harvard Annals, vol. xxviii. pp. 93, 99.

Footnote 516:

The Observatory, vol. xxii. p. 387.

Footnote 517:

Phil. Trans. vol. cliv. p. 431.

Footnote 518:

Bothkamp Beob. Heft ii. p. 28.

Footnote 519:

Astr. Nach. No. 3034.

Footnote 520:

Harvard Annals, vol. xxviii. p. 93.

Footnote 521:

A. C. Maury, Harvard Annals, vol. xxviii. pp. 92, 100.

Footnote 522:

Leavenworth, Publ. Leander M‘Cormick Observatory, vol. i. pt. iv. p. 96.

Footnote 523:

A. C. Maury, Harvard Annals, vol. xxviii. pp. 17, 119.

Footnote 524:

Pickering, Astroph. Journ. vol. vi. p. 350.

Footnote 525:

Huggins, Atlas of Spectra, p. 164, plate xii.; Bélopolsky, Astr. Nach. No. 3510.

Footnote 526:

Astroph. Journ. vol. viii. p. 307.

Footnote 527:

Nature, vol. lx. p. 249.

Footnote 528:

Maunder, Knowledge, vol. xiv. p. 73.

Footnote 529:

Astroph. Journ. vol. vi. p. 326.

Footnote 530:

Atlas of Spectra, p. 160.

Footnote 531:

Monthly Notices, vol. xxxvii. p. 278. The difficulties in applying the theory were pointed out by Vogel, Astr. Nach. No. 2141.

Footnote 532:

Scheiner, Astr. Nach. No. 2924; Potsdam Publ. Bd. vii. p. 232.

Footnote 533:

Comptes Rendus, t. cxxi. p. 629.

Footnote 534:

Sitzungsberichte, Berlin, 17th Nov. 1898.

Footnote 535:

Astr. and Astrophysics, vol. xii. p. 719.

Footnote 536:

Phil. Trans. vol. clxxxiv. p. 696.

Footnote 537:

Atlas of Spectra, Plate ix.

Footnote 538:

Atlas of Spectra, p. 69.

Footnote 539:

Comptes Rendus, t. cxxi. p. 629.

Footnote 540:

The method usually employed is that given by Lehmann-Filhés, Astr. Nach. No. 3242.

Footnote 541:

A. C. Maury, Astroph. Journ. vol. viii. p. 174.

Footnote 542:

Harvard Annals, vol. xxvi. p. xviii.; Harvard Circular, No. 11; Astr. Nach. No. 3017; Monthly Notices, vol. l. p. 297.

Footnote 543:

Sitzungsberichte, Berlin, 2nd May 1901; Astroph. Journ. vol. xiii. p. 324.

Footnote 544:

Astr. Nach. No. 3456.

Footnote 545:

Comptes Rendus, t. xiii. p. 438; quoted by Gore, Knowledge, vol. xxii. p. 201.

Footnote 546:

Monthly Notices, vol. li. p. 316.

Footnote 547:

Astr. Nach. No. 3242.

Footnote 548:

Ibid. No. 3629.

Footnote 549:

Vogel, ibid. No. 3017.

Footnote 550:

Astroph. Journ. vol. viii. p. 173.

Footnote 551:

Harvard Circular, Nos. 11, 21.

Footnote 552:

Sitzungsberichte, Berlin, 24th April 1890; Astr. Nach. No. 2995.

Footnote 553:

Astroph. Journ. vol. v p. 1.

Footnote 554:

Memorie degli Spettroscopisti Italiani, vols. xxvi., xxviii.; Bulletin de l’Acad. des Sciences, St. Pétersbourg, t. vi. No. 1, t. viii. No. 2.

Footnote 555:

See Observatory, vol. xxiii. p. 127.

Footnote 556:

Astroph. Journ. vol. x. p. 177; Observatory, vol. xxiii. p. 92.

Footnote 557:

Ibid. vols. xxii. p. 436, xxiii. p. 93; Monthly Notices, vol. lx. p. 418.

Footnote 558:

Astr. Journ. No. 484.

Footnote 559:

Monthly Notices, vols. lx. p. 595, lxi. p. 70.

Footnote 560:

Astroph. Journ. vol. xiii. p. 89.

Footnote 561:

See Appendix, Table II., for a list of the spectroscopic binaries discovered down to the middle of the year 1902.

Footnote 562:

Harvard Annals, vol. xxviii. p. 104.

Footnote 563:

Observatory, vol. xxiii. p. 128 (A. M. Clerke).

Footnote 564:

Proc. Amer. Academy, vol. xvi. p. 27.

Footnote 565:

Popular Astronomy, Oct. 1897, p. 306.

Footnote 566:

Sitzungsberichte, Berlin, 28th Nov. 1889; Astr. Nach. Nos. 2947, 2960.

Footnote 567:

Astr. Journ. vol. vii. p. 165.

Footnote 568:

Knowledge, vol. xv. p. 86 (A. M. Clerke).

Footnote 569:

Astr. Journ. Nos. 255, 256, 257.

Footnote 570:

Bauschinger, V. J. S. Astr. Ges., Jahrgang xxix.; Chase, Astr. Journ. No. 218.

Footnote 571:

Boss, Astr. Journ. No. 343; Yendell, Pop. Astr. Dec. 1897, p. 401.

Footnote 572:

Comptes Rendus, t. cxx. p. 125; Bull. Soc. Astr. de France, 1895, p. 73.

Footnote 573:

Astr. Journ. No. 318.

Footnote 574:

Astr. Nach. No. 804.

Footnote 575:

Schönfeld, V. J. S. Astr. Ges., Jahrgang ix. p. 230; Sirius, Bd. x. p. 68; Argelander, Bonner Beob. Bd. vii. p. 397.

Footnote 576:

Astroph. Journ. vol. x. p. 317.

Footnote 577:

Schönfeld, Jahresbericht, Mannheim, Bd. xl. p. 76.

Footnote 578:

Beobachtungen Veränderlicher Sterne, Th. iii. p. 21.

Footnote 579:

Astr. Nach. No. 3474.

Footnote 580:

Journ. Brit. Astr. Assoc. vol. i. pp. 137, 255.

Footnote 581:

Chandler, Astr. Journ. No. 205.

Footnote 582:

Astr. Journ. No. 373; Astroph. Journ. vol. iv. p. 267.

Footnote 583:

Roberts, Astroph. Journ. vol. x. p. 313.

Footnote 584:

Proc. Amer. Acad. vol. xvi. p. 350; Astr. Nach. No. 3385.

Footnote 585:

Astr. Journ. No. 199; Popular Astr. Sept. 1897, p. 239.

Footnote 586:

V. J. S. Astr. Ges. Jahrgang xxvi. Th. ii.; Potsdam Annual Report.

Footnote 587:

Chandler, Astr. Journ. Nos. 199, 294, 396.

Footnote 588:

Tisserand, Bull. de la Soc. Astr. de France, Mars 1895.

Footnote 589:

Astr. Journ. Nos. 162, 294.

Footnote 590:

System of the Stars, p. 142.

Footnote 591:

Astr. Nach. Nos. 3091, 3467; Astr. Journ. No. 265; Trans. Swedish Acad. of Sciences, 1892, No. 7.

Footnote 592:

Yendell, Astr. Journ. Nos. 163, 185; Knowledge, vol. xvi. p. 166 (A. M. Clerke).

Footnote 593:

Astroph. Journ. vol. xi. p. 190.

Footnote 594:

I.e. the interval between one perihelion passage and the next.

Footnote 595:

Russell, Astroph. Journ. vol. x. p. 318.

Footnote 596:

Astr. Journ. Nos. 327, 383.

Footnote 597:

Ibid. No. 383; Astroph. Journ. vol. iv. p. 272.

Footnote 598:

Chandler, “Third Catalogue of Variable Stars,” Astr. Journ. No. 379.

Footnote 599:

Astr. Journ. No. 326.

Footnote 600:

Ibid. Nos. 329, 384, 415.

Footnote 601:

Monthly Notices, vol. lv. p. 211.

Footnote 602:

Astr. Journ. No. 327; Astroph. Journ. vol. iv. p. 270.

Footnote 603:

Ibid. vol. x. p. 314.

Footnote 604:

Keeler, ibid. vol. i. p. 262.

Footnote 605:

Astr. Journ. No. 328.

Footnote 606:

Astroph. Journ. vols. i. p. 294; iii. p. 348; Astr. Journ. Nos. 374, 384, 422.

Footnote 607:

Yendell, ibid. No. 366.

Footnote 608:

Harvard Circulars, Nos. 3, 4.

Footnote 609:

Astroph. Journ. vol. iii. p. 213.

Footnote 610:

Pickering, ibid. vol. vii. p. 23.

Footnote 611:

Astr. Journ. Nos. 447, 450; Luizet, Astr. Nach. No. 3596.

Footnote 612:

Astr. Journ. No. 468.

Footnote 613:

Astroph. Journ. vol. xiii. p. 177.

Footnote 614:

Astr. Nach. Nos. 3572, 3567; Parkhurst, Astr. Journ. No. 475.

Footnote 615:

Harvard Circulars, Nos. 44, 47.

Footnote 616:

Astr. Journ. No. 508; Proc. Royal Society of Edinburgh, 4th Nov. 1901.

Footnote 617:

Astr. Nach. Nos. 3748, 3765; Astr. Journ. No. 517.

Footnote 618:

Such have recently been detected by Chandler in Algol, Astr. Journ. Nos. 509, 511.

Footnote 619:

Astr. Nach. Nos. 3257, 3338; Bull. de l’ Acad. St. Pétersbourg, 1894, p. 268; Astroph. Journ. vol. i. pp. 160, 263.

Footnote 620:

Astroph. Journ. vol. ii. p. 288.

Footnote 621:

Astroph. Journ. vol. iii. p. 227.

Footnote 622:

Ibid. vol. i. p. 160.

Footnote 623:

Astroph. Journ. vol. vi. p. 393; Bull. de l’Acad. de St. Pétersbourg, t. vii. No. 4, 1900.

Footnote 624:

Astroph. Journ. vol. ix. p. 59.

Footnote 625:

Chandler, Third Catalogue, No. 8073 and note.

Footnote 626:

Journ. Brit. Astr. Assoc. vol. vii. p. 471.

Footnote 627:

Astr. Nach. No. 3483; Luizet, ibid. No. 3570; Flanery, Knowledge, vol. xxiii. p. 134; Harvard Circular, No. 41.

Footnote 628:

Sometimes designated SU Cygni.

Footnote 629:

Lockyer, Proc. Royal Society, vol. lix. p. 101.

Footnote 630:

Its fourth member, Y Sagittarii, was added by Sawyer in 1886, Astr. Journ. No. 328; Yendell, Pop. Astr. vol. ii. p. 364.

Footnote 631:

Chandler, Astr. Journ. Nach. No. 2749; Yendell, Astr. Journ. Nos. 157, 321; Pop. Astr. vol. ii. p. 207.

Footnote 632:

Astr. Journ. No. 374.

Footnote 633:

Bonner Beob. Bd. vii. p. 393.

Footnote 634:

Astr. Nach. Nos. 1745, 2420.

Footnote 635:

Ibid. No. 3565.

Footnote 636:

Astroph. Journ. vol. xiii. p. 94.

Footnote 637:

Astr. Journ. Nos. 378, 384; Astroph. Journ. vol. x. p. 312; Nature, vol. lxiv. p. 469.

Footnote 638:

Astr. Journ. vols. ix. pp. 180, 183, 190; x. p. 11.

Footnote 639:

Astroph. Journ. vol. iv. p. 141.

Footnote 640:

Astr. Journ. No. 413.

Footnote 641:

Pickering, Astr. Nach. No. 3008.

Footnote 642:

Chandler, Astr. Journ. Nos. 358, 374, 426.

Footnote 643:

Harvard Circular, Nos. 23, 25.

Footnote 644:

Astroph. Journ. vol. viii. p. 163.

Footnote 645:

Harvard Circular, No. 33; Harvard Annals, vol. xxxviii. pp. 144, 160 (Bailey).

Footnote 646:

Cf. Observatory, vol. xx. p. 54.

Footnote 647:

Astr. Nach. No. 3410.

Footnote 648:

Astr. Journ. No. 477; Astroph. Journ. vol. xiii. p. 177; Nature, 12th September 1901.

Footnote 649:

Harvard Circular, No. 21.

Footnote 650:

Since the above was written, Miss A. J. Cannon has made the brief statement (Harvard Annals, vol. xxviii. p. 177) that the 34^h period satisfies all observations.

Footnote 651:

Astr. Nach. No. 3483.

Footnote 652:

Astr. Nach. No. 3570.

Footnote 653:

Harvard Circular, No. 41.

Footnote 654:

Astr. Journ. No. 331.

Footnote 655:

S. I. Bailey, Astroph. Journ. vol. x. p. 257.

Footnote 656:

S. I. Bailey, Harvard Annals, vol. xxxviii. p. 209.

Footnote 657:

Monthly Notices, vol. lxi. p. 163.

Footnote 658:

Bailey, Harvard Annals, vol. xxxviii. p. 234.

Footnote 659:

See Knowledge, vol. xvii. p. 128 (A. M. Clerke).

Footnote 660:

Frost, Astroph. Journ. vol. ii. p. 383.

Footnote 661:

Astr. Nach. No. 3565.

Footnote 662:

History of Astronomy, 4th ed. p. 379 (A. M. Clerke).

Footnote 663:

Astr. Nach. No. 3051.

Footnote 664:

Astr. and Astrophysics, vol. xiii. p. 575.

Footnote 665:

Monthly Notices, vol. lvii. p. 6; Observatory, vol. xx. p. 87.

Footnote 666:

Harvard Annals, vol. xxviii. p. 103.

Footnote 667:

Sitzungsberichte, Berlin, 8th Feb. 1894.

Footnote 668:

Monthly Notices, vols. liv. p. 94; lvii. p. 515.

Footnote 669:

Memorie degli Spettroscopisti Italiani, t. xxvi., June 1897.

Footnote 670:

Astroph. Journ. vol. vii. p. 1.

Footnote 671:

Astr. and Astrophysics, vol. xii. p. 356.

Footnote 672:

Baxendell, Proc. Manchester Phil. Society, vol. xxiv. p. 14.

Footnote 673:

Flanery, Knowledge, vol. xix. p. 230.

Footnote 674:

Bonner Bcob. Bd. vii. Th. ii. p. 332.

Footnote 675:

Phil. Trans. vol. lxx. p. 342.

Footnote 676:

Schmidt, quoted by Schönfeld, Mannheimer Jahresbericht, Bd. xl. p. 74.

Footnote 677:

Nijland, Astr. Nach. No. 3733.

Footnote 678:

Guthnick (Astr. Nach. No. 3745) holds that the star rises to exceptionally high maxima once in 59½ years. As the Italian proverb says, Chi vivrà, vedrà.

Footnote 679:

Berliner Jahrbuch, 1841, p. 93 (Olbers).

Footnote 680:

Miscellanea Berolinensia, t. i. p. 208.

Footnote 681:

Bonner Beob. Bd. vii. p. 340.

Footnote 682:

Humboldt’s Cosmos (Otté’s trans.), vol. iii. p. 236.

Footnote 683:

Roberts, Astr. Journ. Nos. 295, 491–2.

Footnote 684:

A. J. Cannon, Harvard Annals, vol. xxviii. p. 189.

Footnote 685:

Roberts, Astr. Journ. No. 462.

Footnote 686:

Astroph. Journ. vol. ii. p. 198.

Footnote 687:

Baxendell, Journ. Liverpool Astr. Soc. vol. iii. p. 52.

Footnote 688:

Schönfeld, Astr. Nach. No. 2066.

Footnote 689:

Peek, Journ. Brit. Astr. Assoc. vol. ix. p. 261.

Footnote 690:

Astr. Nach. No. 3025; Hartwig, ibid. Nos. 3211, 3596.

Footnote 691:

Hale, Yerkes Observatory Bulletin, No. 13.

Footnote 692:

Journ. Brit. Astr. Assoc. vol. ix. p. 260.

Footnote 693:

Astr. Nach. No. 2859.

Footnote 694:

Peek, Variable Star Notes, No. 4.

Footnote 695:

Townley, Publ. Washburn Observatory, vol. vi. pt. iii. p. 60.

Footnote 696:

Astroph. Journ. vol. i. p. 305.

Footnote 697:

Parkhurst, Popular Astronomy, vol. i. p. 462.

Footnote 698:

Schmidt, Astr. Nach. No. 1897; Chandler, Astr. Journ. Nos. 186, 193.

Footnote 699:

Parkhurst, Pop. Astr. vol. i. p. 266.

Footnote 700:

Reed, Astr. Journ. No. 330.

Footnote 701:

Peek, Variable Star Notes, No. 2, p. 13.

Footnote 702:

Knott, Observatory, vol. xiii. p. 111.

Footnote 703:

Astr. Nach. No. 3184.

Footnote 704:

Bulletin de l’Acad. Imp. t. xxix. p. 302.

Footnote 705:

Peek, Knowledge, vol. xv. p. 52.

Footnote 706:

Yerkes Observatory Bulletin, No. 13.

Footnote 707:

Knowledge, vol. xix. p. 230.

Footnote 708:

Ibid. vol. xx. p. 237.

Footnote 709:

Pop. Astr. vol. v. p. 164.

Footnote 710:

Yendell, ibid. p. 17.

Footnote 711:

Astr. Journ. No. 400.

Footnote 712:

Pickering, Astroph. Journ. vol. iv. p. 370.

Footnote 713:

Parkhurst, Pop. Astr. July 1900, p. 343.

Footnote 714:

Astroph. Journ. vol. xii. p. 268.

Footnote 715:

Vierteljahrsschrift Astr. Ges. Jahrgang xxxiv. p. 315.

Footnote 716:

Astr. Nach. No. 3553.

Footnote 717:

Astr. Nach. Nos. 2075, 2420, 2491, 2492.

Footnote 718:

Astr. Journ. Nos. 491, 492 (1901).

Footnote 719:

Astr. Nach. No. 1905.

Footnote 720:

Journ. Brit. Astr. Assoc. vol. v. p. 262.

Footnote 721:

Pickering, Proc. Amer. Acad. vol. xii. p. 403.

Footnote 722:

Schönfeld, Mannheimer Jahresberichte, Bd. xl. p. 113.

Footnote 723:

Monthly Notices, vol. xvii. p. 23.

Footnote 724:

B.D. + 30° 591, now known as X Persei.

Footnote 725:

Astr. Journ. Nos. 434, 462; Astr. Nach. No. 3577.

Footnote 726:

Safarik, Journ. Brit. Astr. Assoc. vol. ii. p. 293.

Footnote 727:

Astr. Nach. No. 3011.

Footnote 728:

Astr. Journ. No. 231.

Footnote 729:

Peek, Journ. Brit. Astr. Assoc. vols. ix. p. 260; x. p. 156.

Footnote 730:

Miss Cannon found indications, in the spectrum of η Carinæ, of a composite origin from a solar, and a bright-line helium star. Harvard Annals, vol. xxviii. p. 175. Sir David Gill recorded numerous spectral coincidences between the southern variable and Nova Aurigæ. Monthly Notices, vol. lxi. p. 456.

Footnote 731:

Monthly Notices, vol. vi. p. 244.

Footnote 732:

System of the Stars, p. 116.

Footnote 733:

Roberts, Astr. Journ. No. 492, p. 89.

Footnote 734:

Astr. Nach. Nos. 624, 796, 806.

Footnote 735:

Gore, Revised Cat. of Var. Stars, 1888.

Footnote 736:

Astr. Journ. No. 151.

Footnote 737:

H. Corder, Memoirs Brit. Astr. Assoc. vol. v. pt. ii. p. 32.

Footnote 738:

Astr. Nach. No. 2704.

Footnote 739:

A. C. Maury, Harvard Annals, vol. xxviii. p. 31.

Footnote 740:

Monthly Notices, vols. l. p. 94; lv. p. 445.

Footnote 741:

Monthly Notices, vol. lix. p. 374.

Footnote 742:

Ibid. vol. lx. p. 425.

Footnote 743:

Knowledge, vol. xvi. p. 124.

Footnote 744:

Gore, ibid. vol. xxii. p. 176.

Footnote 745:

Astr. Nach. No. 3475.

Footnote 746:

Astr. Nach. No. 3118.

Footnote 747:

Astr. and Astrophysics, vol. xi. p. 393.

Footnote 748:

Ibid. p. 810.

Footnote 749:

Ibid. vol. xii. p. 159.

Footnote 750:

Abhandlungen der Kön. Akad. Berlin, 1893, p. 58.

Footnote 751:

Discourse at the Royal Institution, 13th May 1892.

Footnote 752:

Astr. and Astrophysics, vol. xi. p. 607.

Footnote 753:

Ibid. p. 907.

Footnote 754:

Campbell, Astr. and Astrophysics, vol. xi. p. 715.

Footnote 755:

Huggins, Proc. Royal Society, vol. liv. p. 30.

Footnote 756:

Astr. and Astrophysics, vol. xii. p. 728.

Footnote 757:

Astr. and Astrophysics, vol. xii. p. 54.

Footnote 758:

Publ. Pacific Society, vol. iv. p. 246.

Footnote 759:

Campbell, Astroph. Journ. vols. i. p. 49; v. p. 240.

Footnote 760:

Huggins, Astr. and Astrophysics, vol. xiii. p. 239.

Footnote 761:

Peek, Journ. Brit. Astr. Assoc. vol. ix. p. 260.

Footnote 762:

Rambaut, Observatory, vol. xxiv. p. 261.

Footnote 763:

Ibid. p. 360; Barnard, Astroph. Journ. vol. xiv. p. 152; Monthly Notices, vol. lxii. p. 61.

Footnote 764:

Campbell, Astroph. Journ. vol. i. p. 51.

Footnote 765:

Pickering, Astr. and Astrophysics, vol. xiii. pp. 40, 398.

Footnote 766:

Astr. and Astrophysics, vol. xiii. p. 311; Astr. Nach. No. 3211.

Footnote 767:

Harvard Circular, No. 1.

Footnote 768:

Harvard Circular, No. 4.

Footnote 769:

Ibid. No. 4; Astroph. Journ. vol. iii. p. 214.

Footnote 770:

W. J. Hussey, Astr. Journ. No. 383; Publ. Pacific Society, vol. viii. p. 220.

Footnote 771:

Astroph. Journ. vol. v. p. 233.

Footnote 772:

Harvard Circular, No. 42; Astroph. Journ. vol. ix. p. 269 (Pickering).

Footnote 773:

Ibid. p. 308.

Footnote 774:

E. C. Pickering, Astroph. Journ. vol. xii. p. 52; Harvard Circular, No. 56; Astr. Nach. Nos. 3651, 3664.

Footnote 775:

Astroph. Journ. vol. xii. p. 258.

Footnote 776:

Harvard Circular, Nos. 56, 57.

Footnote 777:

Sitzungsberichte, Berlin, 21 März 1901.

Footnote 778:

Rev. W. Sidgreaves, Observatory, vol. xxiv. p. 192.

Footnote 779:

Monthly Notices, vols. lxi. pp. 388, 462; lxii. p. 521.

Footnote 780:

Ibid. vol. lxi. p. 464.

Footnote 781:

Harvard Circular, No. 59.

Footnote 782:

Yerkes Observatory Bulletin, Nos. 16, 17.

Footnote 783:

This was assured by Campbell’s determinations (Lick Bulletin, No. 8).

Footnote 784:

Lick Bulletin, No. 8; Sidgreaves, Astr. Nach. No. 3741; Von Gothard, ibid. No. 3738.

Footnote 785:

Astr. Nach. Nos. 3752, 3753.

Footnote 786:

Astroph. Journ. vol. xiv. p. 167.

Footnote 787:

Ibid. p. 293.

Footnote 788:

Lick Bulletin, No. 10.

Footnote 789:

Ibid. No. 14.

Footnote 790:

Astr. Nach. No. 3756.

Footnote 791:

Nature, 30th Jan. 1902.

Footnote 792:

Astr. Nach. No. 3771.

Footnote 793:

Astroph. Journ. vol. xvi. p. 38.

Footnote 794:

Astr. Nach. No. 3603.

Footnote 795:

Vierteljahrsschrift Astr. Ges. Jahrg. xxxi. p. 258.

Footnote 796:

Astr. Nach. Nos. 3118, 3187, 3598.

Footnote 797:

Nature, vol. lxiv. p. 253.

Footnote 798:

The fifth and sixth stars of the trapezium have, however, certainly gained brightness of late. Comas Solà, Astr. Nach. No. 3751.

Footnote 799:

The radial velocity of η Geminorum proved variable on Campbell’s examination in 1902. Lick Bulletin, No. 20.

Footnote 800:

Bull. Société Astr. de France, Mars 1895, p. 85.

Footnote 801:

Publicationen der Hamburger Sternwarte, 1874, No. 1.

Footnote 802:

Publicationem der Hamburger Sternwarte, p. 79.

Footnote 803:

Astroph. Journ. vol. i. p. 11.

Footnote 804:

Roberts, Celestial Photographs, vol. i. p. 39.

Footnote 805:

Der Sternhaufen χ Persei, 1878, p. 30.

Footnote 806:

Phil. Trans. vol. cxxiii. p. 373.

Footnote 807:

Webb, Cel. Objects, ed. Espin, vol. ii. p. 200.

Footnote 808:

Astr. and Astrophysics, vol. xiii. p. 180.

Footnote 809:

Astron. Mittheilungen der kön. Sternwarte zu Göttingen, Th. iv.; see also Schlesinger’s “Measurement of the Rutherfurd Photographs of the Præsepe Group,” Contributions from the Columbia University, No. 15, 1898.

Footnote 810:

Harvard Annals, vol. xxvi. pt. ii. p. 264.

Footnote 811:

W. C. Kretz, Contributions from the Columbia University, No. 16, 1900, p. 478.

Footnote 812:

Harvard Annals, vol. xxvi. p. 283.

Footnote 813:

Transactions Yale Observatory, vol. i. pt. i. 1887.

Footnote 814:

Astroph. Journ. vol. v. p. 352.

Footnote 815:

Astr. Nach. No. 3441.

Footnote 816:

Astronomy and Astrophysics, vol. xiii. p. 193.

Footnote 817:

Astr. Nach. Nos. 3018, 3032.

Footnote 818:

Ibid. No. 3074; Publ. Lick Observatory, vol. ii. p. 174.

Footnote 819:

Journ. Brit. Astr. Assoc. vol. ix. p. 133.

Footnote 820:

Astr. Nach. No. 3441.

Footnote 821:

Ibid. No. 3253; Monthly Notices, vol. lx. p. 258.

Footnote 822:

Astr. Nach. No. 3275; Sirius, 1891, p. 106. Wolf’s photographs were taken previously, but interpreted subsequently to Barnard’s.

Footnote 823:

Pop. Astr. Feb. 1899.

Footnote 824:

Monthly Notices, vol. lx. p. 259.

Footnote 825:

A. C. Maury, Harvard Annals, vol. xxviii. p. 20.

Footnote 826:

See ante, p. 230.

Footnote 827:

Astr. Mittheilungen, Th. iii.; quoted in Observatory, vol. xvii. p. 309.

Footnote 828:

Bull. Société Astr. de France, 1896, p. 293.

Footnote 829:

Astr. Nach. Nos. 3587, 3588.

Footnote 830:

Vogel, Jahresbericht, 1899.

Footnote 831:

Monthly Notices, vol. lvii. p. 16.

Footnote 832:

Knowledge, vol. xx. p. 194.

Footnote 833:

Clerke, System of the Stars, p. 284.

Footnote 834:

Astr. Nach. No. 3111; Astr. and Astrophysics, vol. xiii. p. 792.

Footnote 835:

Astr. Nach. No. 3535.

Footnote 836:

Cf. photographs of the cluster and nebula by Naegamvala, Knowledge, vol. xix. p. 183, and by Roberts, ibid. vol. xxiii. p. 132.

Footnote 837:

Sidereal Messenger, vol. ix. p. 47.

Footnote 838:

Astr. Nach. No. 2918; Astr. and Astrophysics, vol. xiii. p. 178.

Footnote 839:

Ibid. p. 643.

Footnote 840:

Gore, Knowledge, vol. xxii. p. 201.

Footnote 841:

Abhandl. der kön. Sächs. Ges. Bd. xv. Th. i. 1889.

Footnote 842:

Reproduced in Knowledge, vol. xix. p. 109.

Footnote 843:

Astr. and Astrophysics, vol. xiii. p. 642.

Footnote 844:

Astr. and Astrophysics, vol. xiii. pp. 180, 182.

Footnote 845:

Publ. Lick Observatory, vol. iii. p. 202.

Footnote 846:

Cape Results, p. 115.

Footnote 847:

See Knowledge, vol. xxi. p. 279.

Footnote 848:

Bailey, Astr. and Astrophysics, vol. xii. p. 689.

Footnote 849:

Pickering, Harvard Annals, vol. xxvi. p. 218.

Footnote 850:

Ibid. p. 221.

Footnote 851:

Ibid. p. 220.

Footnote 852:

Phil. Trans. vol. cli. p. 732.

Footnote 853:

Publ. Pacific Society, vol. iii. p. 375.

Footnote 854:

Ibid. No. 70, p. 201.

Footnote 855:

Astroph. Journ. vol. x. p. 246.

Footnote 856:

Astroph. Journ. vol. xii. p. 181.

Footnote 857:

Abhandl. der Kön. Preuss. Akad. 1892, Anhang.

Footnote 858:

J. Herschel, Cape Results, pp. 23, 113, Plate vi. Fig. 14.

Footnote 859:

Engl. Mechanic, vol. li. p. 378; Sidereal Messenger, vols. ix. p. 380; x. p. 107.

Footnote 860:

Monthly Notices, vol. 1. p. 517.

Footnote 861:

Astroph. Journ. vol. ii. p. 321; Harvard Annals, vol. xxxviii., contains a complete discussion of these variables by Bailey.

Footnote 862:

Address on Astronomical Photography, p. 26; Knowledge, vol. xxi. p. 280 (Clerke).

Footnote 863:

Harvard Circular, No. 33.

Footnote 864:

Astroph. Journ. vol. x. p. 255.

Footnote 865:

Publ. Pacific Society, No. 70, p. 210.

Footnote 866:

Astr. Nach. No. 3519.

Footnote 867:

Parkhurst, Astr. Journ. No. 482.

Footnote 868:

Trans. Royal Dublin Society, vol. ii. p. 132.

Footnote 869:

Bélopolsky, Astr. Nach. No. 3338.

Footnote 870:

Celestial Photographs, vol. i. p. 119.

Footnote 871:

Secchi, Atti dell’ Accad. Pont. t. vii. p. 90, 1853.

Footnote 872:

Harvard Circular, No. 33.

Footnote 873:

Harvard Annals, vol. xxxviii. p. 234.

Footnote 874:

Astroph. Journ. vol. x. p. 263.

Footnote 875:

Harvard Annals, vol. xxvi. p. 247.

Footnote 876:

General Astronomy, section 891.

Footnote 877:

Astr. Nach. 3549; Astroph. Journ. vol. ix. p. 149.

Footnote 878:

Atlas of Stellar Spectra, p. 125.

Footnote 879:

Celestial Photographs, vol. ii. p. 63.

Footnote 880:

Scheiner, Photographie der Gestirne, p. 332.

Footnote 881:

This is denied by M. Antoniadi, on the strength of an observation with the giant siderostat of Paris, 1st Sept. 1900 (Knowledge, vol. xxiii. p. 251).

Footnote 882:

Swift, Pop. Astr. vol. i. p. 112.

Footnote 883:

Rabourdin, Cosmos, 19 Fevrier 1898, p. 232.

Footnote 884:

Cape Results, p. 53.

Footnote 885:

Knowledge, vol. xxiii. p. 132.

Footnote 886:

Trans. Royal Dublin Society, vol. ii. p. 79.

Footnote 887:

Engl. Mechanic, vol. xlii. p. 311.

Footnote 888:

Celestial Photographs, vol. i. p. 78.

Footnote 889:

Astr. Nach. No. 3601.

Footnote 890:

Astroph. Journ. vol. xi. p. 3.

Footnote 891:

Astronomical and Physical Researches at Daramona, Appended Illustrations.

Footnote 892:

Astroph. Journ. vol. xiv. p. 34.

Footnote 893:

Trans. Royal Dublin Society, vol. ii. p. 135.

Footnote 894:

Trans. Royal Dublin Society, vol. ii. p. 50.

Footnote 895:

Observatory, vol. xii. p. 84.

Footnote 896:

Cape Results, pp. 20, 94.

Footnote 897:

Rosse, Trans. Royal Dublin Society, vol. ii. p. 19.

Footnote 898:

Ibid. p. 57.

Footnote 899:

They seem to have been depicted two months earlier by Max Wolf. See Astr. Nach. Nos. 3214, 3217.

Footnote 900:

Astr. and Astrophysics, vol. xiii. p. 183.

Footnote 901:

Celestial Photographs, vol. ii. p. 159.

Footnote 902:

Ibid. vol. i. p. 41.

Footnote 903:

Astroph. Journ. vol. xi. p. 4.

Footnote 904:

Celestial Photographs, vol. ii. p. 135.

Footnote 905:

Sitzungsberichte der kgl. bayer. Akad. der Wissenschaften, Bd. xxxi. Heft ii. p. 111 (1901).

Footnote 906:

Astr. and Astrophysics, vol. xii. p. 300.

Footnote 907:

Published as an “Inaugural Dissertation” at Berlin in 1892.

Footnote 908:

Astroph. Journ. vol. xi. p. 347.

Footnote 909:

Gen. Cat. Nos. 3572, 3574; Phil. Trans. vol. cxxiii. p. 496.

Footnote 910:

Monthly Notices, vol. lii. p. 458.

Footnote 911:

Monthly Notices, vol. lii. p. 453.

Footnote 912:

Sterngruppen und Nebelmassen, p. 33.

Footnote 913:

Phil. Trans. vol. cxl. p. 512, plate xxxvii. fig. 6.

Footnote 914:

Memoirs Royal Astr. Society, vol. xxiii. p. 62.

Footnote 915:

Monthly Notices, vol. xlvii. p. 416.

Footnote 916:

Copernicus, vol. i. p. 50.

Footnote 917:

Popular Astronomy, vol. i. p. 370.

Footnote 918:

Trans. Royal Dublin Society, vol. ii. p. 97.

Footnote 919:

Astr. Nach. No. 3517.

Footnote 920:

Monthly Notices, vol. xlviii. p. 331.

Footnote 921:

Celestial Photographs, vol. i. p. 131.

Footnote 922:

Astr. Nach. No. 3168.

Footnote 923:

J. Herschel, Phil. Trans. vol. cxxiii. p. 403; Rosse, Trans. Royal Dublin Soc. vol. ii. p. 95; Spitaler, Astr. Nach. No. 3168.

Footnote 924:

See a photograph by Roberts, Celestial Photographs, vol. ii. p. 135.

Footnote 925:

Lick Publications, vol. iii. p. 204.

Footnote 926:

Cape Results, p. 20.

Footnote 927:

Trans. Royal Dublin Society, vol. ii. p. 118.

Footnote 928:

Astr. Nach. No. 3517.

Footnote 929:

J. Herschel, Phil. Trans. vol. cxxiii. p. 431.

Footnote 930:

Ibid. vol. cxl. p. 512.

Footnote 931:

J. Herschel, Cape Results, p. 22.

Footnote 932:

Astr. Nach. No. 2755.

Footnote 933:

Pickering, Harvard Circular, No. 12.

Footnote 934:

Popular Astronomy, vol. i. p. 370.

Footnote 935:

Astr. Nach. No. 3704.

Footnote 936:

Sitzungsberichte, Munich, 23rd March 1901, p. 111.

Footnote 937:

Astr. Nach. No. 3517.

Footnote 938:

Phil. Trans. vol. lxxxi. p. 71.

Footnote 939:

Leipzig Abhandl. Bd. iii. p. 314.

Footnote 940:

Trans. Royal Dublin Society, vol. ii. p. 40; Phil. Trans. vol. cli. p. 714.

Footnote 941:

Lick Publications, vol. ii. p. 161.

Footnote 942:

Astr. Nach. No. 3111.

Footnote 943:

Since the above words were written it has been applied. Professor Frost examined, in September 1902, a spectrograph of S.D. −10° 4713 taken by Mr. Ellerman in 1899, and finds it to bear authentic marks of the helium type.

Footnote 944:

Sidereal Messenger, vol. iv. p. 39.

Footnote 945:

Astr. and Astrophysics, vol. xiii. p. 177.

Footnote 946:

Ibid. p. 181.

Footnote 947:

Astr. Nach. No. 2683.

Footnote 948:

Ibid. No. 3111.

Footnote 949:

Ibid. No. 3101.

Footnote 950:

Monthly Notices, vol. lii. p. 442.

Footnote 951:

Ibid. p. 454.

Footnote 952:

Publications of the Yerkes Observatory, vol. i. p. 75.

Footnote 953:

Knowledge, vol. xvii. p. 17; Astr. Journ. No. 447.

Footnote 954:

Publications of the Yerkes Observatory, vol. i. p. 227.

Footnote 955:

Celestial Cycle, p. 152 (ed. 1881).

Footnote 956:

Phil. Trans. vol. cxxiii. p. 380.

Footnote 957:

Ibid. vol. cxl. p. 514, fig. 16; Trans. Royal Dublin Society, vol. ii. p. 50.

Footnote 958:

Phil. Trans. vol. cxci. p. 129.

Footnote 959:

W. H. Pickering, Harvard Annals, vol. xxxii. p. 66.

Footnote 960:

Knowledge, vol. xvii. p. 17.

Footnote 961:

Astr. Nach. No. 2707.

Footnote 962:

Monthly Notices, vol. xlix. p. 363.

Footnote 963:

Ingall, ibid. p. 420.

Footnote 964:

Popular Astronomy, Sept. 1897, pp. 229, 232.

Footnote 965:

Phil. Trans. vol. cliv. p. 442.

Footnote 966:

Astr. Nach. No. 1613.

Footnote 967:

Monthly Notices, vol. xlii. p. 446.

Footnote 968:

Comptes Rendus, t. xc. p. 837.

Footnote 969:

Monthly Notices, vol. xlii. p. 446.

Footnote 970:

Publ. Lick Observatory, vol. iii. p. 203.

Footnote 971:

Cf. J. H. Jeans, “On the Stability of a Spherical Nebula,” Phil. Trans. vol. cxcix. A, p. 1.

Footnote 972:

Ginzel, Astr. Nach. No. 2829.

Footnote 973:

Lick Publications, vol. iii. p. 209.

Footnote 974:

System of the Stars, p. 256, Fig. 35.

Footnote 975:

Publ. Lick Observatory, vol. iii. p. 212.

Footnote 976:

Phil. Trans. vol. xcii. p. 522.

Footnote 977:

Trans. Royal Dublin Society, vol. ii. p. 93.

Footnote 978:

Celestial Photographs, vol. ii. p. 127.

Footnote 979:

Phil. Trans. vol. cxxiii. p. 402.

Footnote 980:

Ibid. vol. cxl. plate xxxvii. fig. 11, p. 513.

Footnote 981:

Phil. Trans. vol. cli. p. 721.

Footnote 982:

Publ. Lick Observatory, vol. iii. p. 203.

Footnote 983:

Monthly Notices, vol. lvi. p. 379.

Footnote 984:

Astr. Journ. vol. ii. p. 141.

Footnote 985:

Publ. Lick Observatory, vol. ii. p. 159.

Footnote 986:

Astr. Nach. No. 3017; Burnham, Monthly Notices, vol. lii. pp. 33, 449.

Footnote 987:

Ibid. vol. xlviii. p. 388.

Footnote 988:

Monthly Notices, vol. lii. p. 40; Publ. Lick Observatory, vol. ii. p. 165.

Footnote 989:

Ibid. vol. iii. p. 217.

Footnote 990:

Astr. Nach. No. 1885.

Footnote 991:

Publ. Lick Observatory, vol. iii. pp. 212, 217 (Keeler).

Footnote 992:

This assertion must be qualified if Miss Cannon’s observation of the line λ 5007 in certain members of the Wolf-Rayet family be substantiated. Harvard Annals, vol. xxviii. p. 141.

Footnote 993:

Wilsing and Scheiner, Astr. Nach. No. 3805.

Footnote 994:

Campbell, Astr. and Astrophysics, vol. xiii. p. 494.

Footnote 995:

A formula connecting these three lines into a series has been published by Mr. E. F. J. Love (Monthly Notices vol. lxii. p. 524), but their conformity to it may be purely accidental.

Footnote 996:

Ferry’s experiments at Upsala in 1898 went to show that C gains in relative strength with diminishing pressure (Physical Review, vol. vii. p. 6).

Footnote 997:

Campbell, Astr. and Astrophysics, vol. xiii. p. 496.

Footnote 998:

Publ. Lick Observatory, vol. iii. p. 209.

Footnote 999:

Astr. and Astrophysics, vol. xiii. p. 495.

Footnote 1000:

Ibid. vol. xii. pp. 52, 55.

Footnote 1001:

Astr. Nach. Nos. 2292, 2293, 2309.

Footnote 1002:

Publ. Lick Observatory, vol. iii. p. 214.

Footnote 1003:

Astr. and Astrophysics, vol. xiii. p. 498.

Footnote 1004:

Ibid. vol. xii. p. 55.

Footnote 1005:

Astr. Nach. No. 2353; Copernicus, vol. i. p. 2.

Footnote 1006:

Monthly Notices, vol. xxxiv. p. 71.

Footnote 1007:

Keeler, Publ. Lick Observatory, vol. iii. p. 214.

Footnote 1008:

Monthly Notices, vol. lii. pp. 45, 46.

Footnote 1009:

Memoirs Royal Astr. Society, vol. xxiii. p. 61.

Footnote 1010:

Monthly Notices, vol. lii. p. 31.

Footnote 1011:

Publ. Lick Observatory, vol. iii. p. 211.

Footnote 1012:

Astr. and Astrophysics, vol. xii. p. 52.

Footnote 1013:

Observatory, vol. v. p. 26.

Footnote 1014:

D’Arrest, Leipzig Abhandl. Bd. iii. p. 308, 1857.

Footnote 1015:

Wilsing, Astr. Nach. Nos. 3190, 3261.

Footnote 1016:

Kleiber, Astr. Nach. No. 3037.

Footnote 1017:

Astroph. Journ. vol. x. p. 197.

Footnote 1018:

Astr. Jahrbuch, 1788, p. 242; Phil. Trans. vol. lxxv. p. 263.

Footnote 1019:

Monthly Notices, vol. xxxvi. p. 66.

Footnote 1020:

Ibid. vol. xlviii. p. 387.

Footnote 1021:

Phil. Trans. vol. cxxxiv. plate xix. fig. 29.

Footnote 1022:

Nature, vol. xliii. p. 420.

Footnote 1023:

Astr. Jahrbuch, 1803, p. 106.

Footnote 1024:

Trans. Royal Dublin Society, vol. ii. p. 152.

Footnote 1025:

Astr. Nach. No. 1018.

Footnote 1026:

Nova Acta Societatis R. Upsaliensis, ser. iii. vol. ix. p. 99, 1874.

Footnote 1027:

Astr. Nach. No. 2186.

Footnote 1028:

Astr. Journ. No. 200.

Footnote 1029:

Potsdam Publ. No. 14, p. 35.

Footnote 1030:

Astr. Nach. No. 2800.

Footnote 1031:

Astroph. Journ. vol. x. p. 199.

Footnote 1032:

Astr. Nach. No. 3200.

Footnote 1033:

Monthly Notices, vol. lx. p. 245.

Footnote 1034:

Ibid. p. 257.

Footnote 1035:

Astr. and Astrophysics, vol. xii. pp. 52, 55.

Footnote 1036:

Ibid. vol. xiii. p. 497.

Footnote 1037:

Trans. Royal Dublin Society, vol. ii. p. 156.

Footnote 1038:

Monthly Notices, vol. lii. p. 44.

Footnote 1039:

Celestial Photographs, vol. ii. p. 133.

Footnote 1040:

Publ. Pacific Society, vol. xi. p. 180.

Footnote 1041:

Knowledge, vol. xxiii. p. 250.

Footnote 1042:

Memoirs Royal Astr. Society, vol. xxxvi. p. 47.

Footnote 1043:

Monthly Notices, vol. lii. p. 38.

Footnote 1044:

Cape Results, p. 114.

Footnote 1045:

Swift, Pop. Ast. December 1897, p. 426.

Footnote 1046:

Phil. Trans. vols. cxl. p. 513; cli. p. 716.

Footnote 1047:

Memoirs Royal Astr. Society, vol. xxiii. p. 60.

Footnote 1048:

Celestial Photographs, vol. ii. p. 35.

Footnote 1049:

Cape Results, p. 90, plate vi. fig. 7.

Footnote 1050:

Potsdam Publ. No. 14, p. 37.

Footnote 1051:

Phil. Trans. vol. cli. plate xxx. fig. 40.

Footnote 1052:

Monthly Notices, vol. lii. p. 46.

Footnote 1053:

Publ. Lick Observatory, vol. iii. p. 215.

Footnote 1054:

Astr. and Astrophysics, vol. xiii. p. 499.

Footnote 1055:

English Mechanic, vol. xlii. p. 311.

Footnote 1056:

Harvard Annals, vol. xxxiii. p. 146.

Footnote 1057:

Publ. Pacific Society, No. 70, p. 201, 1899.

Footnote 1058:

Scheiner, Astr. Nach. No. 3086; Wilsing, ibid. No. 3261.

Footnote 1059:

Monthly Notices, vol. xlviii. p. 393.

Footnote 1060:

Knowledge, vol. xv. p. 149.

Footnote 1061:

Potsdam Publ. No. 14, p. 38.

Footnote 1062:

Publ. Lick Observatory, vol. iii. p. 213; Astroph. Journ. vol. x. p. 195.

Footnote 1063:

Astr. Nach. No. 3086.

Footnote 1064:

Phil. Trans. vol. cxl. p. 514, fig. 15.

Footnote 1065:

Abhandl. Leipziger Akad. Bd. iii. p. 321; Astr. Nach. No. 1885.

Footnote 1066:

Memoirs Royal Astr. Society, vol. xxiii. p. 61.

Footnote 1067:

Les Étoiles, t. ii. p. 16.

Footnote 1068:

Monthly Notices, vol. xxviii. p. 154.

Footnote 1069:

Ibid. vol. lii. p. 35.

Footnote 1070:

Ibid. vol. lx. p. 256.

Footnote 1071:

Comas Solà, Astr. Nach. No. 3751.

Footnote 1072:

Knowledge, vol. xii. p. 147.

Footnote 1073:

Ibid. vol. xx. p. 193.

Footnote 1074:

Astr. Nach. No. 3027.

Footnote 1075:

Harvard Annals, vol. xxxii. p. 66.

Footnote 1076:

Astr. and Astrophysics, vol. xiii. p. 813.

Footnote 1077:

Harvard Annals, vol. xxxii. p. 77.

Footnote 1078:

Astr. Nach. No. 3513.

Footnote 1079:

Jahrbuch der Erfindungen, 1898, p. 101; Potsdam Publ. Bd. xi.

Footnote 1080:

Harvard Annals, vol. xxxii. p. 80.

Footnote 1081:

Vogel, Sitzungsberichte, Berlin, 13 März 1902.

Footnote 1082:

Astroph. Journ. vol. x. p. 29.

Footnote 1083:

Astr. Nach. No. 3476.

Footnote 1084:

Publ. Lick Observatory, vol. iii. p. 224.

Footnote 1085:

Astroph. Journ. vol. ix. p. 312.

Footnote 1086:

Astroph. Journ. vol. viii. p. 32; Astr. Nach. No. 3471.

Footnote 1087:

Astroph. Journ. vol. ix. p. 133.

Footnote 1088:

Ibid. p. 140.

Footnote 1089:

Publ. Pacific Society, vol. v. p. 207.

Footnote 1090:

Astr. Nach. No. 3476.

Footnote 1091:

Proc. Royal Society, vol. lviii. p. 255.

Footnote 1092:

Proc. Royal Society, vol. xlvi. p. 41.

Footnote 1093:

Astr. and Astrophysics, vol. xiii. p. 478.

Footnote 1094:

Washington Observations, 1878, App. i.

Footnote 1095:

Publ. Leander M‘Cormick Observatory, vol. i. pt. vii. p. 274.

Footnote 1096:

Mémoires de l’Acad. de St. Pétersbourg, t. v. No. 4, p. 115.

Footnote 1097:

Publ. Leander M‘Cormick Observatory, vol. i. p. 333.

Footnote 1098:

Knowledge, vol. xvii. p. 133.

Footnote 1099:

Copied in Knowledge, vol. xvi. p. 69.

Footnote 1100:

Phil. Trans. 1786, p. 494; 1789, p. 247; 1811, p. 289; quoted by Holden, American Journ. of Science, vol. xiv. p. 434, 1877.

Footnote 1101:

Memoirs Royal Astr. Society, vol. iii. p. 63.

Footnote 1102:

Reproduced in Astroph. Journ. vol. xi. p. 325.

Footnote 1103:

Popular Astronomy, vol. i. p. 251.

Footnote 1104:

Publ. Lick Observatory, vol. iii. p. 205.

Footnote 1105:

Astroph. Journ. vol. ii. p. 162.

Footnote 1106:

Phil. Trans. vol. cxxiii. p. 461.

Footnote 1107:

Cape Results, p. 10.

Footnote 1108:

Sidereal Messenger, vol. iv. p. 38.

Footnote 1109:

Celestial Photographs, vol. i. p. 101.

Footnote 1110:

Amer. Journ. of Science, vol. xi. p. 341, third series.

Footnote 1111:

Monthly Notices, vol. xlvii. p. 420.

Footnote 1112:

Forty-Seventh Annual Report.

Footnote 1113:

Harvard Annals, vol. xxvi. p. 206.

Footnote 1114:

Astroph. Journ. vol. ii. p. 350.

Footnote 1115:

Astr. Nach. No. 3082.

Footnote 1116:

Ibid. No. 3157.

Footnote 1117:

Ibid. No. 3301; Knowledge, vol. xix. p. 205.

Footnote 1118:

Knowledge, vol. xvii. p. 17.

Footnote 1119:

Ibid. vol. xiv. pp. 188, 230; Observatory, vol. xiv. p. 301; Astr. Nach. No. 3048.

Footnote 1120:

Knowledge, vol. xxii. p. 132.

Footnote 1121:

Astr. and Astrophysics, vol. xi. p. 528; Wolf, Astr. Nach. No. 3130.

Footnote 1122:

Celestial Photographs, vol. i. p. 113.

Footnote 1123:

Astr. Nach. No. 3738.

Footnote 1124:

Cape Results, p. 20.

Footnote 1125:

Ibid. p. 24.

Footnote 1126:

Conn. des Temps pour 1784, p. 229.

Footnote 1127:

Smyth, Celestial Cycle, p. 145 (ed. 1881).

Footnote 1128:

Phil. Trans. vols. cxxxiv. p. 322, cli. p. 715; Trans. Royal Dublin Soc. vol. ii. p. 47.

Footnote 1129:

Celestial Photographs, vol. i. p. 52.

Footnote 1130:

Harvard Annals, vol. xiii. pp. 64, 66.

Footnote 1131:

Phil. Trans. vol. cli. p. 713, plate xxv. fig. 6.

Footnote 1132:

Comptes Rendus, t. cxxvi. p. 1191.

Footnote 1133:

Phil. Trans. vol. cli. p. 713; Trans. Royal Dublin Society, vol. ii. p. 32.

Footnote 1134:

Webb, Celestial Objects, vol. ii. p. 188 (5th edition).

Footnote 1135:

Trans. Royal Dublin Society, vol. ii. p. 51.

Footnote 1136:

Knowledge, vol. xviii. p. 253.

Footnote 1137:

Smyth, Celestial Cycle, p. 361.

Footnote 1138:

Harvard Annals, vol. xxxiii. p. 144.

Footnote 1139:

J. Herschel, Phil. Trans. vol. cxxiii. p. 434; Rosse, Trans. Royal Dublin Society, vol. ii. p. 122.

Footnote 1140:

Celestial Photographs, vol. i. p. 81.

Footnote 1141:

Smyth, Celestial Cycle, p. 472; Webb, Celestial Objects, vol. ii. p. 137.

Footnote 1142:

Phil. Trans. vol. clvi. p. 390; Harvard Annals, vol. xxxiii. p. 144.

Footnote 1143:

Trans. Royal Dublin Society, vol. ii. p. 150.

Footnote 1144:

Ibid. p. 123.

Footnote 1145:

Celestial Photographs, vol. ii. p. 129.

Footnote 1146:

Sidereal Messenger, vol. iv. p. 4.

Footnote 1147:

Dreyer, Memoirs Royal Astr. Society, vol. xlix. p. 215.

Footnote 1148:

Monthly Notices, vol. lii. p. 455.

Footnote 1149:

Astr. Nach. No. 1391.

Footnote 1150:

Ibid. No. 1366.

Footnote 1151:

Lick Publications, vol. ii. p. 176.

Footnote 1152:

Monthly Notices, vol. lvi. p. 66.

Footnote 1153:

Monthly Notices, vol. lix. p. 372.

Footnote 1154:

Ibid. vol. lx. p. 424.

Footnote 1155:

Astr. Nach. No. 1689; Barnard, Monthly Notices, vol. lv. p. 442.

Footnote 1156:

Monthly Notices, vol. l. p. 440.

Footnote 1157:

Astr. Nach. No. 2212.

Footnote 1158:

Monthly Notices, vol. lv. p. 451.

Footnote 1159:

Quoted by Bigourdan, Comptes Rendus, t. cxii. p. 471.

Footnote 1160:

Astr. Nach. Nos. 3030, 3167, 3168.

Footnote 1161:

Publications of the Lick Observatory, vol. ii. p. 172.

Footnote 1162:

Astr. Nach. No. 3097; Monthly Notices, vol. lv. p. 452.

Footnote 1163:

Astr. Nach. No. 3097.

Footnote 1164:

Observatory, vol. xv. p. 104.

Footnote 1165:

Denning, Astr. Nach. No. 3111.

Footnote 1166:

Astr. and Astrophysics, vol. xi. p. 566.

Footnote 1167:

Monthly Notices, vol. xxxviii. p. 104; Astr. Nach. No. 2293; V. J. S. Astr. Ges. Jahrgang xiv. p. 167.

Footnote 1168:

Publ. Lick Observatory, vol. ii. p. 172.

Footnote 1169:

Memoirs Royal Astr. Society, vol. xlix. p. 213.

Footnote 1170:

Publ. Lick Observatory, vol. ii. p. 176.

Footnote 1171:

Ranyard, Knowledge, vol. xv. p. 132.

Footnote 1172:

Knowledge, vol. xv. p. 191.

Footnote 1173:

Phil. Trans. vol. clviii. p. 72.

Footnote 1174:

Knowledge, vol. xix. p. 39.

Footnote 1175:

Clerk Maxwell, Theory of Heat, 10th ed. p. 245.

Footnote 1176:

Cardiff Address, p. 21.

Footnote 1177:

E. S. Ferry, Physical Review, vol. vii. p. 6; Lewis, Astroph. Journ. vol. x. p. 141.

Footnote 1178:

Maunder, Knowledge, vol. xix. p. 286.

Footnote 1179:

Barnard, Monthly Notices, vol. l. p. 310.

Footnote 1180:

Ibid. p. 314; Astr. and Astrophysics, vol. xiii. p. 179.

Footnote 1181:

Astroph. Journ., vol. ix. p. 157.

Footnote 1182:

Ranyard, Knowledge, vol. xiv. p. 112.

Footnote 1183:

Barnard, Report Harvard Conference, Aug. 1898, p. 19.

Footnote 1184:

Burns, Knowledge, vol. xxii. p. 227.

Footnote 1185:

Ibid. vol. xix. p. 205.

Footnote 1186:

Annals of Cape Observatory, vol. iii. p. 22 (Introduction).

Footnote 1187:

Knowledge, vol. xiv. p. 51.

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