Part 2 — INDEX
Reading edition
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; 554photograph 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; 555description 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, α2, 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
556Crab 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; 557red 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 α2 Centauri, 182, 269; oxygen in stars, 191; α2 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 L2 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 D3, 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; 558bright 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 S2 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 D3, 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; 559of 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 R2 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; 560colours 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
561Mendenhall, 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
562Olbers, 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 S2 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
563Pogson, 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 R2 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
564Safarik, 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
565Spectra, 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
566Telluric 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 S2 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
567Wilson, 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
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