WeRead Powered by ReaderPub
Astronomy cover

Astronomy

Chapter 47: INDEX
Open in WeRead

About This Book

This volume offers a compact survey of astronomical knowledge, opening with a historical sketch tracing the development of celestial science from ancient observers to modern advances. It then explains fundamental principles of spherical and gravitational astronomy and describes the instruments and observational techniques used by astronomers. A substantial section surveys the solar system, treating the sun, planets, satellites, comets, asteroids, meteors, and their observable phenomena. The final part examines the sidereal heavens, discussing stars, constellations, stellar distances and motions, nebulae, and star clusters, supplemented throughout by diagrams, photographs, and practical data.

INDEX

  • A
  • Aberration of light, discovered, 18;
    • a proof of the earth’s revolution, 57;
    • of meteor-radiants, 396
  • Aboul Wefa, the moon’s variation, 5
  • Acceleration, 152
  • Achromatic lens, 177
  • Adams, 449;
    • discovery of Neptune, 32, 349;
    • orbit of November meteors, 393
  • Aerolites. See Meteorites
  • Airy, reduction of Greenwich observations, 19;
    • search for Neptune, 32
  • Albategnius, movement of the sun’s apogee, 5
  • Albedo of Mercury, 274;
    • of Venus, 278;
    • of the earth, 289;
    • of the moon, 290;
    • of Mars, 298, 334;
    • of asteroids, 312;
    • of Jupiter, 320;
    • of Jupiter’s satellites, 330, 332;
    • of Saturn, 334;
    • of rings, 338;
    • of Titan, 342;
    • of Uranus, 345;
    • of Neptune, 349
  • Alcor, 402
  • Alcyone, 499–502
  • Aldebaran, 403, 404, 407, 415, 421, 423, 427
  • Algol, 407, 415, 453, 457, 469–474
  • Almagest, 4, 6
  • Al-Mamûm’s school of astronomy at Baghdad, 5
  • Alphard, 409, 415
  • Alphonsine tables, 6
  • Al-Sûfi, description of the stars, 5;
    • Alphard, red, 415;
    • Algol, red, 472
  • Altair, 404, 427
  • Altazimuth, 184, 202
  • Altitude, 65
  • Amplitude, 66
  • Anderson, Dr., discovery of new star, 489
  • Andromeda nebula, 409, 529–532
  • Andromedæ, Gamma, 412, 417
  • — Nova, 489, 491
  • Andromede meteor-showers, 393, 394
  • Angelot, lunar volcanic action, 293
  • Annular eclipse, 113
  • — nebulæ, 526, 527
  • Antares, 404, 415
  • Anthelmus, new star, 484
  • Antlia, 468
  • Aphelion, 75
  • Apogee, 89
  • Apse Line, 75
  • Aquilæ, Eta, 467
  • Arago, nature of meteorites, 392;
    • parallax of 61 Cygni, 422
  • Arc of meridian, 130
  • Arcturus, 403, 405, 406, 415, 423, 427
  • Argelander, solar translation, 28;
    • survey of the heavens, 38;
    • comet of 1811, 357;
    • estimate of stars of ninth magnitude, 541
  • Argo Nebula, 522, 523, 549
  • — Eta, 462–464
  • Argon, not a solar element, 250;
    • peculiar qualities, 255;
    • found in meteorites, 389
  • Aries, first point of, 67
  • Aristarchus, heliocentric system, 4
  • Aristotle, description of a comet, 358
  • Asteroids, position in solar system, 229, 230, 310;
    • discoveries, 311, 314;
    • diameters, 312, 315;
    • computation of orbits, 314;
    • numbers and joint mass, 315;
    • distribution, 316;
    • groups, 317;
    • origin, 318
  • Asterope, 498, 499
  • Astronomy, Greek, 3, 4;
    • Arab, 4–6;
    • Tartar, 5;
    • of the Invisible, 31;
    • gravitational, 11, 33;
    • spectroscopic, 33–36;
    • photographic, 36–38
  • Astrophysics, foundation of, 36
  • Atmosphere, of the sun, 240, 271;
  • Atmospheric refraction, 52
  • Augmentation of moon’s diameter, 144
  • Aurigæ Beta, 404, 454, 456, 457
  • — New Star, 489
  • Auroræ, magnetic relations, 17, 288
  • Auwers’ reduction of Bradley’s observations, 19;
    • proper motion of Sirius, 437
  • Azimuth, 65
  • B
  • Babinet, rarity of cometary matter, 366
  • Baden-Powell, Sir George, eclipse-expedition, 259;
    • coronal photographs, 271
  • Bailey, Prof., 441, 464, 511, 513, 539
  • Ball, Sir Robert, 422, 433
  • Barnard, Prof., photograph of corona of January 1, 1889, 268–9;
    • effect of totality, 270;
    • zodiacal counterglow, 272;
    • photograph of eclipsed moon, 296;
    • drawing of Mars, 302;
    • seas of Mars, 306;
    • measurements of asteroids, 312;
    • markings on Jupiter’s satellites, 330;
    • discovery of fifth satellite, 331;
    • measures of Saturn, 335;
    • of ring-system, 330;
    • disappearance of rings, 337;
    • eclipse of Japetus, 338;
    • compression of Uranus, 343, 344;
    • Encke’s comet, 366;
    • comet-photographs, 378–381;
    • Swift’s comet, 383;
    • Nova in Auriga, 494;
    • Alcyone, 500;
    • curved nebulosity stretching over constellation of Orion, 520;
    • annular nebulæ, 526;
    • stars in streams, 551;
    • vacancies in the Milky Way, 554
  • Base line, 131
  • Baxendell, 484
  • Bayer, 404, 529
  • Behrmann, 400, 433, 541
  • Bellatrix, 408
  • Bélopolsky, spectrographic determination of Jupiter’s rotation, 325;
    • absolute velocity of 61 Cygni, 427;
    • spectroscopic examination of Castor, 451;
    • observation of Delta Cephei, 456;
    • Beta Lyræ, 466–467
  • Berberich, variability of Encke’s comet, 360
  • Berson, aeronautic ascent, 286
  • Bessel, Fundamenta Astronomiæ, 19;
    • astronomy of the invisible, 31, 32;
    • measurement of the Pleiades, 37;
    • Halley’s comet, 355;
    • comet of 1807, 362;
    • Epsilon Lyræ, 411
  • Betelgeuse, 404, 408, 415, 427
  • Bianchi, 459
  • Bianchini, rotation of Venus, 280
  • Biela, discovery of a comet, 365
  • Bigelow, theory of Zodiacal Light, 272
  • Binary stars, 431
  • Biot, meteoric fall, 387
  • Bird, quadrants, 19, 20
  • “Bird, Red,” 415
  • Birmingham, 417, 485, 486
  • “Blaze Star,” 485, 487
  • Bliss, astronomer-royal, 19
  • Bode’s law, 145, 232, 311, 317, 349
  • Boeddicker, Dr., heat-phases of eclipsed moon, 295
  • Bolometer, 226, 239
  • Bompas, 430
  • Bond, W. C., discoveries of Hyperion and of Saturn’s dusky ring, 25, 336, 341;
    • celestial photography, 36, 37;
    • the great nebula, 530
  • Bradley, discoveries of aberration and nutation, 18, 20;
    • reduction of his observations, 19;
    • Saturn’s rings, 337;
    • the distance of stars, 419–420;
    • Gamma Virginis, 445–446
  • Brahé, Tycho, the moon’s variation, 5;
    • career, 8;
    • scheme of the celestial movements, 9
  • Bredichin, theory of comets’ tails, 369, 370.
    • (See also Tycho.)
  • Brenner, ashen light of Venus, 279;
    • rotation of Venus, 280
  • Brightest stars, 403, 404, 546
  • Brinkley, 422
  • British catalogue, 15, 16
  • Brooks’ cometary discoveries, 365, 371, 380
  • Bunsen, foundation of spectrum analysis, 33
  • Burnham, 433, 437, 441, 448, 509
  • C
  • Calcium, represented in Fraunhofer spectrum, 230;
    • in chromospheric and prominence-spectra, 258, 261, 262
  • Calendar, 86
  • Callandreau, capture of comets, 372
  • Campbell, Prof., spectrum of Mars, 306;
    • mountains on, 307
  • Canals of Mars, 301–305
  • Cancri, S., 474
  • — Zeta, 439, 440
  • Canis Majoris, R, 473
  • Canopus, 403
  • Capella, 403, 406, 415, 427
  • Capricornus, 411
  • Capture-theory of comets, 372
  • Carbon in sun, 242, 250;
    • in comets, 368;
    • in meteorites, 389
  • Cardinal points, 51
  • Carrington, sun-spot zones, 247;
  • Casey, 433
  • Cassegrain telescope, 180
  • Cassini, rotation of Venus, 280;
    • red spot on Jupiter, 323;
    • division of Saturn’s rings, 336;
    • discoveries of Saturnian satellites, 341
  • Cassiopeia, Chair of, 405, 481, 549
  • Cassiopeiæ, Eta, 413, 450
  • Castor, 404, 406, 413, 450, 451
  • Catalogues of stars, 70
  • Celoria, 433, 442, 540
  • Centauri, Alpha, 410, 413, 422, 440, 441
  • — Omega, 512, 513, 516, 539
  • — R, 478
  • Cephii Delta, 417, 456, 466
  • — U, 474
  • Ceraski, luminous night-clouds, 286;
    • discovery of U Cephei, 474
  • Ceres, discovery, 311;
    • diameter, 312
  • Cerulli, rotation of Venus, 280
  • Ceti, Mira, 458
  • Challis, search for Neptune, 32
  • Chandler, 462, 472, 476
  • Charlois, asteroidal discoveries, 314
  • Chemistry, universal, 35, 36;
  • Chromosphere, 253, 258
  • Chronograph, 175
  • Chronometer, 175
  • Circle, meridian, 198;
  • Circumpolar stars, 46
  • Clairaut, verification of Newton’s law, 11;
    • calculation of Halley’s comet, 16
  • Clark, Alvan, great refractors, 26
  • — — G., detection of the companion of Sirius, 26, 437
  • Clarke, dimensions of earth, 134
  • Clausen, groups of comets, 361
  • Clerke, Agnes, appearance of R Sculptoris, 416;
    • examination of Pickering’s catalogue of stars, 541;
    • estimate of total light of stars to magnitude 9½, 543
  • Clock, astronomical, 174;
    • driving, 186;
    • sidereal, 68
  • Clock stars, 82
  • Clusters, globular, 507–517;
    • irregular, 497–507
  • “Coal sacks” in Milky Way, 554
  • Coelostat, 194
  • Collimation of transit instrument, 200
  • Collimator of spectroscope, 215
  • Colours of double stars, 417
  • Comæ Berenices, 434, 502, 549
  • Comet, Aristotle’s, 352, 353;
  • — Halley’s, return in 1759, 16, 17;
    • status in solar system, 230, 232;
    • return in 1835, 335, 336;
    • type of tail, 369;
    • a client of Neptune, 371, 372
  • — Encke’s, disturbed by Mercury, 273;
    • rarefaction, 366;
    • acceleration, 307;
    • exempt from Jupiter’s influence, 371
  • — of 1811, structure, 356, 357;
    • type of tail, 369;
    • bulk, 383
  • — of 1843, surprising appearance, 358;
    • conditions of movement, 359
  • — of 1882, photographs, 38, 361;
  • Comet, Biela’s, discovery, 365;
    • duplication, 366;
    • related meteor-swarm, 393, 394
  • — Wells, spectrum, 368
  • — photographically detected, 377
  • Comets, orbits of, 108;
  • — tails, multiple, 354, 355, 361, 377;
    • electrical theory, 357, 369, 383;
    • passage of the earth through, 302, 365;
    • three types, 369;
    • structure shown in photographs, 377, 383
  • Common, Dr., 25, 510, 520, 532, 534
  • Conjunctions, 99, 103
  • Constant of aberration, 59
  • Constellations, 45
  • Contacts in eclipse, 114
  • Copeland, Dr., cometary spectra, 368;
    • Nova in Auriga, 490;
    • helium, 519
  • Copernicus, residence in Italy, 7;
    • theory of planetary revolutions, 8, 9, 418
  • Cornelius, Gamma, 479
  • Corona Borealis, Eta, 437
  • — — Gamma, 442
  • — solar, 253;
    • compound nature of light, 202;
    • daylight photography, 267;
    • periodicity of type, 208, 270, 272;
    • photographs, 268–271;
    • rarefaction, 271, 361;
    • connexion with Zodiacal Light, 272, 273
  • Coronium, 238, 262
  • Co-tidal lines, 165
  • Coudé telescope, 27, 296
  • Crateris, R, 478
  • Craters, lunar, 292, 307
  • Crema meteorite, 386
  • Cross, Southern, 410, 416, 549
  • Crosswires, 195, 199, 206
  • Crucis, Kappa, 506
  • Cygni Beta, 417
  • — Chi, 460
  • — (34), 482
  • — (61), 422, 427
  • — Rho, new star near, 486
  • — Y, 474
  • Cygnus, 407
  • D
  • D’Alembert, verification of Newton’s Law, 11
  • D’Arrest, asteroidal orbits, 316;
  • Darwin, G. H., tidal friction, 236;
    • origin of the moon, 236, 237;
    • density of Saturn, 333
  • Day and night, 52
  • — apparent solar, 79;
    • mean solar, 79
  • Declination, 66
  • De la Rue, celestial photography, 36, 295
  • Delphini, Beta, 435
  • — Gamma, 412
  • Deneb, 407
  • Denning, rotation of Saturn, 334;
    • discovery of a comet, 370;
    • August meteors, 391;
    • meteor-radiants, 395, 396
  • Density of earth, 160
  • Deslandres, prominence-photography, 261;
    • photographs of the sun as a bright-line star, 262;
    • daylight coronal photography, 267;
    • eclipse of 1893, 270;
    • rotation of Jupiter, 325
  • Dewar, atmospheric resistance to meteorites, 388
  • Dhurmsala meteorite, 389
  • Diameters, determination of, 141
  • Diamonds in meteorites, 390
  • Diffraction grating, 216
  • Direct movement, 89
  • — vision spectroscope, 216
  • Distance of the stars, 417
  • Doberck, Dr., 441, 442, 447, 450, 451
  • Dollond, invention of achromatic lenses, 21
  • Donati, discovery of a comet, 362;
    • cometary spectrum, 368
  • Double-slit method of photography, 261
  • Draconis, Gamma, 419, 420
  • Draper, Henry, photograph of the moon, 36
  • Dubjago, 435
  • Dunér, spectroscopic measurement of the sun’s rotation, 249;
    • R Hydræ, 462;
    • Y Cygni, 474;
    • Z Herculis, 475
  • E
  • Earth, shape of, 41, 134;
  • Easton, 532, 548
  • Eccentricity of ellipse, 74
  • Eclipse, solar, of 1842, 253;
  • Eclipses, lunar, 111;
    • partial, 111, 114;
    • annular, 113;
    • magnitude of, 113;
    • total of sun, 113;
    • duration of solar, 115;
    • number of in a year, 118;
    • recurrence of, 119;
    • of satellites, 121;
    • varieties of lunar, 295;
    • of Jupiter’s satellites, 329;
    • of Saturn’s, 342
  • Ecliptic, 56
  • — obliquity of, 61
  • Electrical theory of photospheric radiance, 242;
  • Electra, 498, 499
  • Elements of an orbit, 106
  • Elevating floor, 193
  • Elger, lunar maria, 290
  • Elkin, Dr., transit of great comet, 359;
  • Ellipse, properties of, 73;
    • eccentricity of, 74;
    • foci of, 74;
    • to draw an, 74
  • Elliptical nebulæ, 529–533
  • Elongations, 99
  • Encke, discovery of a comet, 366;
    • resisting medium, 367
  • Enoch, Book of, 404
  • Equation of time, 79
  • Equator, terrestrial, 50;
    • celestial, 66
  • Equatorial coudé, 193
  • Equatorial telescope, 185
  • Equinoxes, 55;
  • Equulei, Delta, 433
  • Eridani, (40), 444
  • Espin, 460, 482, 494
  • Establishment of a port, 165
  • Ether of space, 546
  • Euler, lunar theory, 11
  • Evening star, 100
  • Evolution, of solar system, 235, 310;
  • Eye-pieces, 182
  • F
  • Fabricius, 458, 483
  • Fabry, cometary orbits, 372
  • Faculæ, associated with sun-spots, 244;
    • rotation, 249;
    • photographed, 262
  • Faye, planetary origin, 235, 350;
    • water on Mars, 299
  • Fényi, solar eruptions, 259, 260
  • Finder of telescope, 187
  • First Point of Aries, 67
  • Fixed stars, 45, 423
  • Flammarion, rotation of Venus, 280;
    • canals of Mars, 304;
    • condition of Mars, 309
  • Flamsteed, first astronomer-royal, 15;
    • stellar parallax, 18;
    • Flamsteed’s star, 461
  • Fleming, Mrs., 460, 465, 489, 494–496
  • Fletcher, 447
  • Fomalhaut, 404
  • Fontana, pseudo-satellite of Venus, 282
  • Forbes, ultra-Neptunian planets, 231
  • Foucault’s pendulum, 48–50
  • Fraunhofer, improvement of telescopes, 21;
    • solar spectrum mapped by, 34
  • Fraunhofer lines, 34, 249, 259, 271;
    • interpreted, 35, 250;
    • reflected in spectrum of Uranus, 346;
    • in spectra of comets, 368
  • Fritsche, 433
  • Frost, spectrograph of Uranus, 346
  • Froley, 434
  • G
  • Galaxy. See Milky Way
  • Galileo, telescopic observations, 9;
    • double-star method of parallaxes, 28, 418
  • Gaseous nebula, 517
  • Gemini, star cluster in, 504
  • Geminorum, Zeta, 468
  • Gemma, Cornelius, 479
  • Gemmill, 554
  • Geocentric positions, 70
  • Geodesy, 129
  • Gill, Dr., photographs of comet of 1882, 38, 361;
    • parallax of Sirius, 421;
    • parallax and velocity, Lacaille, 424;
    • Omega Centauri, 513
  • Glasenapp, 433–434
  • Gledhill, red spot on Jupiter, 323
  • Globular clusters, 507
  • Gnomon, 125
  • Goodricke, 465, 466, 470
  • Gould, Dr., photographic measurement of the Pleiades, 37;
    • planetary photography, 327;
    • Pi Gruis and R Sculptoris, 416;
    • Kappa Crucis, 506;
    • stars in Southern Hemisphere, 541;
    • belt of stars intersecting the Milky Way, 551
  • Graduated circles, 171
  • Grating spectroscope, 216
  • Gravity, surface, on Mercury, 274;
    • on Venus, 278;
    • on the moon, 293;
    • on Mars, 298;
    • on Saturn, 335;
    • on Uranus, 345;
    • on Neptune, 349
  • Gravitation, laws of, 153;
    • universal, 156
  • Greenwich observations, 15, 19, 20
  • Groombridge, 424
  • Grosch, corona of 1867, 268
  • Grubb, Sir Howard, great refractors, 26
  • — Thomas, Melbourne reflecting telescope, 24
  • Guinand, optical glass, 21
  • Gully, Ludovic, 488
  • Gylden, 423
  • Gyroscope, 50
  • H
  • Hadley, improvement of reflecting telescopes, 21
  • Hale, spectrographs of prominences, 261;
    • calcium light pictures of sun and surroundings, 262;
    • double-slit method of coronal photography, 267
  • Hall, Prof. Asaph, discovery of the moons of Mars, 26, 309;
    • rotation of Saturn, 334
  • — Chester More, invention of achromatic lenses, 20
  • — Maxwell, 472
  • Halley, law of gravitation, 10;
    • acceleration of the moon, 12;
    • astronomer-royal, 16;
    • comet calculated by, 16;
    • transits of Venus, 17;
    • discovery of proper motion in stars, 423;
    • discovery of the star cluster in Hercules, 507
  • Harding, 548
  • Hartwig, 488
  • Harvest moon, 95
  • Heavens, diurnal motion of, 45
  • Heis, 400, 401, 541
  • Heliocentric positions, 70
  • Heliometer, 209
  • Helium, a chromospheric element, 255, 258;
    • extracted from clevite, 255
  • Helmholtz, maintenance of sun’s heat, 234;
    • past duration of sunlight, 285
  • Hencke, asteroidal discoveries, 314
  • Henderson, 422, 447
  • Henry’s belts of Uranus, 343
  • Hepidannus, 479
  • Herculis, Alpha, 413, 416
  • — Zeta, 435
  • — Z, 475
  • Herschel, Sir John, mathematical analysis at Cambridge, 15;
    • observations of nebulæ, 23, 31;
    • Magellanic clouds, 30, 31;
    • survey of the heavens, 31;
    • photography of sun-spots, 36;
    • telescope, 180;
    • great spot-group in 1837, 244;
    • cyclonic theory of sun-spots, 252;
    • Halley’s comet, 355;
    • comet of 1843, 358;
    • Biela’s comet, 365;
    • red stars, 416;
    • orbit of Gamma Virginis, 446;
    • Kappa Crucis, 506;
    • 2 Messier, 511–512;
    • 22 Messier, 514;
    • nebula round Eta Argus, 522–523;
    • 30 Doradus, 524;
    • the trifid nebula, Sagittarius, 525;
    • planetary nebula, 528–529;
    • the Nubecula Major, 534–536;
    • Milky Way, crossed by zone of large stars, 552;
    • observations in the Southern Hemisphere, 554
  • — Sir William, the sun’s translation, 19, 28;
    • reflecting telescopes, 21–23;
    • discovery of Uranus, 21, 22;
    • of binary stars, 28;
    • comprehensive designs, 27, 29;
    • nebular theory, 30, 35;
    • rotation of Jupiter’s satellites, 331;
    • variability of Japetus, 341;
    • discovery of Uranian moons, 347;
    • binary stars, 419, 431;
    • motion real and apparent, 428;
    • Zeta Herculis, 435;
    • Xi Ursæ Majoris, 440;
    • 70 Ophiuchi, 441;
    • 5 Messier, 510
  • Hevelius, 459, 462, 484
  • Hind, 433, 474, 482, 484
  • Hipparchus, construction of a star catalogue, 3;
    • mathematical standpoint, 4
  • Holden, Prof., solar rotation, 249;
    • names of asteroids, 315;
    • helical nebulæ, 528
  • Holmes, discovery of a comet, 379
  • Holwarda, Phocylides, 458
  • Hooke, law of gravitation, 10;
    • observations of Greek letter Draconis, 18;
    • Gamma Arietis, 412;
    • parallax of Gamma Draconis, 419–420
  • Horizon, visible, 41;
    • sensible, 44;
    • celestial, 44;
    • rational, 44
  • Horrebow, satellite of Venus, 282
  • Hour circle, 186
  • Howlett, depression of sun-spot umbræ, 251
  • Huggins, Dr., stellar and nebular spectra, 35;
    • photographed, 37;
    • observations of prominences, 255;
    • daylight coronal photography, 267;
    • prismatic occultation of a star, 294;
    • spectrum of Mars, 306;
    • of Jupiter, 326;
    • of Uranus, 345;
    • of Winnecke’s comet, 368;
    • spectrograph of Tebbutt’s comet, 368;
    • measurement of motion in the line of sight, 426;
    • spectroscopic examination of new star, 493;
    • spectroscopic examination of the “fish-mouth” nebula, 518;
    • discovery of gaseous spectrum, 528
  • Humboldt, meteoric shower of 1799, 392;
    • temporary star of 1572, 479–481
  • Hussey, cometary forms, 380;
    • photograph of Rordame’s comet, 383
  • Huygens, 417, 517
  • Hyades, 407, 549
  • Hydræ, R, 462
  • Hydrogen, ultra-violet spectrum in stars, 37;
    • a gaseous metal, 250;
    • a constituent of prominences and chromosphere, 255, 258;
    • velocity of molecules, 313;
    • free in atmospheres of Uranus and Neptune, 346, 349;
    • assumed constituent of comets’ tails, 369, 370
  • Hypothesis of external galaxies, 546
  • I
  • Infinity of Space, 546
  • J
  • Jacob, 433, 447
  • Jacoby, measures of photographs, 37
  • Janssen, photograph of the sun, 243;
    • spectroscopic method of prominence-observation, 254;
    • double-slit method, 261
  • Japetus, remarkable eclipse, 338;
    • variability, 341;
    • plane of orbit, 342
  • Jesse, luminous night-clouds, 286
  • Job, Book of, 404
  • Johnson, 450
  • Juno, discovery, 311;
    • diameter and albedo, 312, 316;
    • a twin of Clotho, 317
  • Jupiter, long inequality, 12, 17;
    • disturbance of Halley’s comet, 16;
    • influence upon asteroidal distribution, 316–318;
    • mass and figure, 318;
    • rotation, 318, 325, 326;
    • density, 319, 326;
    • reflective power, 320;
    • belts and streamers, 321, 322, 326;
    • spots, 323, 325;
    • photographs, 327;
    • disturbance of comets, 371
  • Jupiter’s satellites, Galilean quartette, 9, 327, 328;
    • transits, 329;
    • constitution, 330;
    • fifth satellite, 331, 332
  • K
  • Kapteyn, 422, 556, 561–563
  • Keeler, drawings of Jupiter, 321;
    • description of markings, 322;
    • spectroscopic test of the meteoric constitution of Saturn’s rings, 339;
    • measuring velocities of nebula in line of sight, 428;
    • spectra of the Orion nebula, 519–520
  • Kelvin, Lord, subterranean temperature, 285
  • Kepler’s Laws, 10, 155, 339, 417
  • Kirch, 460, 470, 510
  • Kirchhoff, spectrum analysis, 33;
    • Fraunhofer’s lines, 34
  • Kirkwood, distribution of asteroids, 316, 317;
    • divisions in Saturn’s rings, 338
  • Kleiber, number of shooting stars, 390
  • Koch, 461
  • Kreutz, relations of great southern comets, 360
  • Krüger, 442
  • L
  • Lacaille, southern nebulæ, 30
  • Lagrange, verified principle of gravitation, 11;
    • stability of solar system, 13
  • Lajoye, 488
  • Lamp, fate of Brorsen’s comet, 370
  • Lane’s law, 242
  • Langley, solar radiation, 238, 239;
    • spectroscopic effects of sun’s rotation, 249;
    • temperature of the moon, 294;
    • fireball, 386
  • Laplace, verified Newton’s law, 11;
    • lunar acceleration, 12;
    • Mécanique Céleste, 13, 14;
    • nebular hypothesis, 235
  • Lassell, large reflectors, 24;
    • discoveries of Hyperion, Ariel, and Umbriel, 24, 341, 347;
    • Saturn’s dark ring, 336
  • Latitude, terrestrial, 50, 125;
    • celestial, 68;
    • of sun, 77;
    • geocentric, 135;
    • geographical, 135;
    • astronomical, 136;
    • variation of, 136
  • Leland, Miss, 511
  • Leonid meteors, 391–395
  • Leonis, Gamma, 413
  • — R, 461
  • Lepaute, Madame, computation of Halley’s comet, 16
  • Leverrier, discovery of Neptune, 32;
    • intra-Mercurian planet, 232;
    • mass of asteroids, 315;
    • orbit of November meteors, 395
  • Lewis, 426
  • Libræ, Delta, 473
  • Librations, of Mercury, 277;
  • Lick observatory, 25, 26
  • Light-equation, 329
  • “Light journey,” 420
  • Limited number of visible stars, 538, 545
  • Limiting apertures, 212
  • Lippershey, inventor of the telescope, 9
  • Lockyer, spectroscopic observations at the sun’s limb, 254;
    • classification of prominences, 250;
    • solar tornadoes, 259
  • Loewy, Coudé telescope, 27;
    • lunar photography, 296
  • Longitude, terrestrial, 50, 125;
    • celestial, 68
  • Lowell, rotation of Mercury, 277;
    • observations of Venus, 279, 281;
    • lakes of Mars, 301, 302;
    • relation to canals, 302–304
  • Luminous night-clouds, 286
  • Lunar distances, 129
  • — ecliptic limit, 112
  • Lyncis (12), 450
  • Lyra, annular nebula in, 526
  • Lyræ, Beta, 465
  • Lyraid meteors, 393, 395
  • M
  • Maclear, 464
  • Mädler, search for Martian moons, 309;
    • compression of Uranus, 343
  • Madrid meteorite, 385
  • Magellanic clouds, 30, 534–537
  • Magnetism, terrestrial, 287, 288
  • Magnitude, of eclipses, 113;
    • of stars, 212
  • Magnitudes, star, 403, 404
  • Mann, 433
  • Maps, 133
  • Maraldi, 462, 470, 511
  • Marchand, observations of the Zodiacal Light, 273
  • Markwick, Col., 547
  • Mars, phases of, 104;
  • Marth, Neptune’s satellite, 350
  • Mascari, rotation of Venus, 280
  • Maskelyne, astronomer-royal, 19;
    • founded Nautical Almanac, 20;
    • star-motions, 28
  • Mass, defined, 151;
  • Maunder, 460, 488, 493
  • Maxwell, Clerk, constitution of Saturn’s rings, 337, 340
  • Mayer, Tobias, lunar tables, 11;
    • star-motions, 28
  • Mazapil meteorite, 396
  • Measurement, of earth, 42, 129;
    • of sun’s distance, 146;
    • of binary stars, 208;
    • of planets, 208
  • Mécanique Céleste, character, 13, 14
  • Megrez, 402
  • Mercury, Copernican theory of movements, 8;
    • transit of, 101;
    • phases of, 101;
    • orbit, 273, 274;
    • atmosphere, 274, 275;
    • rotation, 275–277;
    • as an abode of life, 277;
    • capture of Encke’s comet, 372
  • Meridian, 50;
  • Merope, 498, 499
  • Messier (3), 509
  • — (5), 510
  • — (11), 506
  • — (22), 514
  • — (37), 505
  • — (51), 533
  • — (57), 526
  • — (80), new star in, 485
  • — (92), 509
  • — (99), 534
  • — discoveries of nebulæ, 30
  • Metonic cycle, 92
  • Meteoric systems, 231, 390, 391;
  • Meteorites, falls, 385–387;
    • legal status, 387;
    • velocities, 387, 388, 390;
    • thumb-marks, 388;
    • chemical composition, 389;
    • enclosed diamonds, 390
  • Meteors, Perseid, 391, 393;
    • Leonid, 391–393;
    • Andromede, 393–394, 396;
    • relations to comets, 393, 395
  • Micrometer, wire, or pillar, 205;
    • evolution of, 207
  • Michell, prevision of binary stars, 28
  • Midnight sun, 63
  • Milky Way, 402, 430, 555, 557
  • — — star streams, 9;
    • disc theory, 29
  • Minimum deviation, 215
  • Mira Ceti, 458, 459
  • Mitchell, 421, 431
  • Mizar, 402, 411, 455, 457
  • Molyneux, 419, 420
  • Montanari, 471
  • Month, 91
  • Moon, acceleration, 12;
    • contumax sidus, 16;
    • observations, 19;
    • apparent motion of, 87;
    • orbit of, 88, 94;
    • phases of, 89;
    • sidereal period of, 89;
    • synodic period of, 91;
    • rotation of, 92;
    • librations of, 93;
    • harvest, 95;
    • high and low, 97;
    • shadow of, 115;
    • distance of, 143;
    • size of, 144;
    • mass of, 158;
    • possible disintegration, 233;
    • origin, 236, 237;
    • rotation, 289;
    • cones and craters, 290, 292, 293;
    • rays and rills, 293;
    • absence of air and water, 294, 313;
    • temperature, 294, 295;
    • eclipses, 295;
    • photography, 295–297
  • Morning star, 100
  • Müller, surface of Mercury, 275;
    • photometry of asteroids, 312;
    • albedo of Jupiter, 320;
    • of Saturn, 334;
    • of Neptune, 349
  • Muscæ, R, 468
  • N
  • Nadir, 45
  • Nasir Eddin, planetary tables, 5
  • Nasmyth, conjunction of Mercury and Venus, 278
  • Nearest fixed stars, 417
  • Nebula, Orion, 23, 25, 30
  • Nebulæ, structure, 23;
  • Nebular hypothesis, 30, 35, 235, 530
  • Nebulous stars, 529
  • Neptune, discovery, 32, 229;
    • distance from the sun, 232;
    • dimensions, 349;
    • compression, 351;
    • retrograde rotation, 351;
    • planets as viewed from, 351, 352;
    • family of comets, 371, 372
  • Neptune’s satellite, discovery, 24;
    • plane of revolution, 350;
    • precessional disturbance, 351
  • Newall, 25-inch refractor, 26
  • Newcomb, Prof., past duration of sunlight, 285;
    • light changes of Ariel, 347;
    • satellite of Neptune, 351;
    • the runaway star, 424;
    • proper motion of Alcyone, 501
  • New stars, 477–497
  • Newton, H. A., capture of comets, 372;
    • meteoric cult, 387;
    • daily number of shooting stars, 390
  • — Sir Isaac, law of gravitation, 10, 11;
    • invention of reflecting telescope, 21;
    • comet of 1680, 355;
    • decay of comets, 366
  • Newtonian telescope, 179
  • Nichol, Dr., 508
  • Niesten, rotation of Venus, 280;
    • mass of asteroids, 315
  • Nodes, 94
  • North polar distance, 66
  • Nova Andromedæ, 488
  • — Aurigæ, 489
  • — Cassiopeiæ, 479
  • — Cygni, 486
  • — Ophiuchi, 484
  • — Serpentarii, 483
  • — Vulpeculæ, 484
  • Nubecula Major, 534
  • — Minor, 535
  • Number of visible stars, 538–544
  • Nutation, 169
  • O
  • Oases of Mars, 302–305
  • Object-glass, achromatic, 177;
    • photographic, 195;
    • photo-telescope, 196
  • Objective prism, 223
  • Obliquity of ecliptic, 61
  • Observatories, 191
  • — Lick, 189, 190, 202
  • — Nice, 192
  • — Yerkes, 189
  • Occultations, 121
  • — of stars, by the moon, 294;
    • by comets, 366
  • Olbers, discovery of Pallas and Vesta, 311;
    • origin of asteroids, 311, 316;
    • electrical theory of comets, 357;
    • classification, 358, 383;
    • comet discovered by, 371
  • Ophiuchi, Nova, 483–485
  • — (70), 441
  • — U, 473, 476
  • Opposition, 103, 105
  • Orbit, of earth, 72, 76;
    • of moon, 88;
    • elements of a planetary orbit, 106;
    • of binary stars, 432
  • Orion, 406, 408, 417
  • — great nebula in, 517–521
  • Orionis, Alpha (Betelgeuse), 404, 408, 415, 427
  • — Iota, 414
  • — Sigma, 414
  • — Theta, 414
  • “Owl,” nebula, 528
  • P
  • P (34) Cygni, 482
  • Palisa, discoveries of asteroids, 314
  • Palitzsch, 470
  • Pallas, discovery, 311;
    • diameter, 312
  • Parallax of stars, 419, 420
  • — diurnal, 140;
    • equatorial horizontal, 140;
    • horizontal, 140;
    • of sun, 146;
    • of Mars, 147
  • Parmentier, distribution of asteroids, 316
  • Pegasus, Square of, 409
  • Pegasi, Kappa, 433
  • — (85), 434
  • — U, 469
  • Pendulum observations, 135;
    • compensated, 174
  • Penumbra, of earth’s shadow, 111
  • Percentage of stars in Milky Way, 547, 548
  • Perigee, 89
  • Perihelion, 75
  • Perrotin, rotation of Venus, 280;
    • of Uranus, 343;
    • markings on Uranus, 344
  • Persei, Beta (Algol). See Algol
  • Perseid meteors, 391;
    • associated with Tuttle’s comet, 393
  • Perseus, 407
  • — star clusters in, 503
  • Perturbations, 158
  • Peters, 428
  • Phases of moon, 89;
  • Phocylides Holwarda, 458
  • Photographic telescopes, 194
  • Photography of nebulæ, 23, 25, 38;
    • of sun-spots, 36, 243, 244;
    • of the moon, 36, 295–297;
    • of stellar spectra, 37;
    • of comets, 38, 354, 377–383;
    • celestial, 194;
    • of spectra, 219, 223;
    • of the eclipsed sun, 254;
    • of the reversing layer, 259;
    • of prominence-spectra, 260;
    • of prominences and faculæ, 261, 262;
    • of the corona, 267, 269–271;
    • planetary, 327; meteoric, 396
  • Photoheliograph, 197
  • Photometers, wedge, 213;
    • meridian, 214
  • Photosphere, visible structure, 242
  • Piazzi, five-foot circle, 20;
    • discovery of Ceres, 311
  • Pickering, Prof. E. C., photometric measures of asteroids, 312;
    • photograph of Jupiter, 327;
    • the spectrum of Alpha Centauri, 441;
    • the spectrum of Pleione, 498
  • Pickering, W. H., lunar photographs, 296;
    • mounting of telescopes, 297;
    • lakes and canals of Mars, 301, 304;
    • water area on Mars, 305;
    • star collisions, 495;
    • nebula surrounding Zeta Orionis, 520
  • Pigott, 467
  • “Pilgrim star,” 479–482
  • Planetary nebulæ, 527–529
  • Planets, apparent movements of, 98;
    • interior and exterior, 98;
    • conjunctions of, 99, 103;
    • phases of, 101, 104;
    • oppositions of, 103;
    • synodic periods of, 107;
    • times of revolution, 107;
    • relative distances of, 144;
    • distances of, 150;
    • terrestrial, 229;
    • giant, 229, 319, 343;
    • trans-Neptunian, 231;
    • intra-Mercurian, 232;
    • decay, 233;
    • comets captured by, 371, 372
  • — minor. See Asteroids
  • Pleiades, 404, 407, 497–502, 539, 549
  • Pleione, 498
  • “Plough,” 400–402, 405
  • Plummer, short-period comets, 371;
    • Encke’s, 372
  • Podmaniczky, Baroness, 488
  • Pogson, 485
  • Polar axis, 185
  • Polaris. See Pole Star
  • Pole, celestial, 46; terrestrial, 50;
    • movements of, 138
  • Pole Star, 46, 405, 412, 421, 427
  • Pollux, 404, 406, 415, 427
  • Pond, defects of Greenwich quadrant, 19;
    • astronomer-royal, 20
  • Position, angle, 208;
  • Poynting’s experiment, 160
  • Præsepe, 502
  • Precession, of equinoxes, 69;
    • effects of, 170;
    • luni-solar, 169
  • Prime vertical, 210
  • Principia, publication, 10, 13;
    • character, 14
  • Prism, action of, 215;
    • objective, 223
  • Prismatic camera, 223
  • — spectroscope, 215
  • Pritchard, Prof., 422, 424
  • Proctor, Saturn’s rings, 341;
    • distance of Uranus, 344;
    • Proctor’s chart, 548;
    • stars in streams, 550
  • Procyon, supposed satellite, 31, 32;
    • order of magnitude, 404;
    • parallax of Procyon, 421;
    • Procyon approaching the Earth, 427
  • Prominences, solar appendages, 253, 254;
    • spectrum, 254, 256, 258, 260;
    • daylight observations, 254, 255;
    • quiescent and eruptive, 256;
    • periodicity, 257;
    • rapid development, 259;
    • spectral photography, 260, 261
  • “Proper motions” of stars, 423–431
  • Ptolemaic system, 3, 4, 6
  • Q
  • Quadrature, 105
  • R
  • Rambaud, absorption in solar atmosphere, 240;
    • fireball, 380
  • Ramsay, terrestrial discovery of helium, 255
  • Ramsden, astronomical circles, 20
  • Raynard, the sun a nebulous body, 253;
    • future of Saturn’s ring-system, 340;
    • outflows from comets, 380;
    • star streams, 551
  • Ravené, gravitational disturbance by asteroids, 315
  • R Centauri, 478
  • Reading microscope, 172
  • Recurrence of eclipses, 119
  • “Red Bird,” 415
  • Red spot on Jupiter, 323, 324
  • Red stars, 416
  • Reduction of observations, 18, 19
  • Refracting telescope, 176
  • Refraction, 52
  • — in Venus, 278
  • Reflecting telescope, 178
  • Regression of moon’s nodes, 94
  • Regulus, 406, 410, 427
  • Retrogradation, 89, 103
  • Reversing layer, 249, 258, 271;
    • photographed, 259
  • Rich and poor regions, 549
  • Richaud, 440
  • Rigel, 404, 414, 427
  • Right ascension, 66
  • Roberts, Dr., 23, 107, 502, 503, 508, 511, 520, 525–528, 530, 533, 534, 539, 540
  • Roberts, A. W., 440, 441, 469
  • Roche, minimum distance of satellites, 340
  • Römer, velocity of light, 329
  • Rosse, Earl of, giant reflector, 24
  • Roszl, mass of 311 asteroids, 315
  • Rotation of earth, 47, 48;
    • of moon, 92
  • Rowland grating, 217
  • — solar elements, 250
  • Russell, photograph of Swift’s comet, 377;
    • Kappa Crucis, 506;
    • the “key-hole” nebula, 522;
    • the Magellanic clouds, 536
  • Rutherfurd, photographs of the moon, 295
  • S
  • Sacrobosco, treatise on the sphere, 6
  • Sagittarii, Zeta, 434
  • Saros, 120
  • Satellites, movements of Satellites, 108;
    • masses of Satellites, 159
  • — discoveries, 9, 23, 25, 26, 309, 347;
  • Saturn, density, 333;
  • Saturn’s ring-system, dusky member, 25, 336, 338;
  • Sawyer, U Ophiuchi discovered, 473;
    • variability of R Canis Majoris detected, 473
  • Schaeberle, photographs of corona of 1893, 270;
    • land and water on Mars, 306
  • Scheiner, spectra of sun-spots, 251
  • Schiaparelli, rotation of Mercury, 275;
    • map of Mercury, 277;
    • rotation of Venus, 280, 281;
    • canals of Mars, 301;
    • duplication, 305;
    • climate of Mars, 308;
    • compression of Uranus, 343;
    • comets and meteors, 393;
    • theory of extinction of light, 544
  • Schiehallion experiment, 161
  • Schmidt, map of the moon, 290
  • Schönfeld, 461, 464, 466, 467, 473, 483
  • Schorr, 442
  • Schur, 433, 442
  • Schuster, photograph of eclipsed sun, 268
  • Schwabe, discovery of sun-spot periodicity, 245
  • Seasons, 61
  • Secchi, observations of prominences, 256;
    • spectrum of Uranus, 345
  • See, Dr., 413, 433–435, 440, 442, 447, 448
  • Seeliger, photometric measures of Saturn’s rings, 339
  • Serpentarii, Nova, 483
  • Sextant, 211
  • Shackleton, photograph of the reversing layer, 259
  • Ship, position of, 128
  • “Sickle” in Leo, 406
  • Siderostat, 194
  • Sidgreaves, elevations of chromosphere, 258
  • Sirius, proper motion, 17, 31;
    • companion, 32;
    • spectrum, 37;
    • size, 403;
    • position, 409;
    • colour, 414;
    • distance, 418, 421;
    • discovery of proper motion, 423;
    • a binary star, 437;
    • comparative magnitude, 438
  • Smyth, 447, 448, 502, 505, 508
  • Solar, constant, 239
  • — diagonal, 183
  • — eclipses, 113
  • — ecliptic limit, 118
  • — System, dominated by gravity, 29;
  • Southern Cross, 410, 416, 549
  • Shouting, 68, 198
  • Spectroheliograph, 225
  • Spectroscope, prismatic, 215;
    • direct vision, 216;
    • grating, 216;
    • Lick star-, 219;
    • Rowland, 217;
    • tele-, 219
  • Spectroscopic measurements of rotation;
  • Spectrum, solar, 34, 250;
    • of stars and nebulæ, 35, 37;
    • measurement of, 218;
    • sun-spot, 250, 251;
    • prominence, 254, 256, 261;
    • chromospheric, 258;
    • of Mercury, 275;
    • of Venus, 279;
    • auroral, 288;
    • of Jupiter, 326;
    • of Saturn’s rings, 338;
    • of Uranus, 345, 346;
    • of Neptune, 351;
    • of comets, 368
  • Spherical excess, 133
  • Spica, 404, 410
  • Spiral nebulæ, 533, 534
  • Spoerer, solar rotation, 249
  • Star of Bethlehem, 101
  • Star-charting, photographic, 38
  • — cluster, 17
  • — spectroscope, 219
  • — time, 68
  • Stars, temporary, 3, 8, 477;
    • proper motions of, 17, 19, 28, 425, 427;
    • fixed, 45;
    • circumpolar, 46;
    • diurnal motion of, 46;
    • aberration of, 58;
    • catalogues of, 71;
    • clock, 82;
    • morning and evening, 100;
    • magnitudes, 403, 404;
    • Pole, 405, 412;
    • double, 410;
    • coloured, 416;
    • red, 416;
    • nearest, 417;
    • binary, 431;
    • variable, 458
  • Stationary points, 103
  • Stone, mass of Titan, 342
  • Stoney, G. Johnstone, atmospheres of planets, 313
  • Stratonoff, sun’s rotation from faculæ, 249
  • Suess, theory of lunar formations, 292
  • Sun, translation, 28, 229;
    • apparent movements of, 55, 77;
    • midnight, 63;
    • apparent diameter of, 72;
    • mean, 79;
    • eclipses of, 113;
    • distance of, 146;
    • mass of, 156;
    • maintenance of heat, 234;
    • radiative power, 237–239, 241, 242;
    • temperature, 239, 240;
    • magnitude, 240, 241;
    • luminous surface, 242;
    • spots, 243–249, 251, 252;
    • periodicity, 246;
    • rotation, 247–249;
    • chemistry, 250;
    • theories, 252
  • Sun-dial, 78
  • Sun’s motion in space, 428
  • Sun-spots, observed by Galileo, 9;
  • Sutton, 553
  • Swift, Lewis, comet discovered by, 377, 378, 383
  • Sykora, elevation of spotted areas on the sun, 252
  • Synodic period, of moon, 91;
    • of planets, 107
  • T
  • Tacchini, spectrum of Venus, 279;
    • rotation, 280
  • Talcott’s latitude method, 124
  • Tauri, Alpha. See Aldebaran
  • — Lambda, 473
  • Tebbutt’s comet, 362, 368
  • Telescope, invention of, 9;
    • achromatic, 20, 21;
    • reflecting, 21, 24, 25, 178;
    • refracting, 20, 25–27, 176;
    • future improvement, 26, 27, 297;
    • Newtonian, 179;
    • Cassegrain, 180, 181;
    • Herschellian, 180;
    • Skew Cassegrain, 181;
    • magnifying power of, 184;
    • illuminating power of, 184;
    • altazimuth, 184;
    • equatorial, 185;
    • Rosse, 187;
    • Common, 5-foot, 188;
    • Lick, 190;
    • fixed, 194;
    • photographic, 194
  • Telespectroscope, 219
  • Tempel, 501
  • “Temporary stars,” 477–497
  • Theodolite, 205
  • Thiele, 435, 447, 451
  • Thome, comet of 1887, 360
  • Tidal evolution, 167
  • Tidal friction, 166;
    • in earth-moon system, 236, 283, 284;
    • on Mercury, 277;
    • effect on satellite-formation, 278, 282;
    • on Venus, 282;
    • on Phobos, 310;
    • on Saturnian satellites, 342
  • Tides, 162;
    • spring and neap, 164;
    • priming and lagging, 164
  • Time, apparent, 78;
    • equation of, 79;
    • mean solar, 79;
    • determination of, 82;
    • at different places, 83;
    • Greenwich mean, 83;
    • local, 83;
    • telegraphy, 84;
    • zone, 84;
    • balls, 85
  • Tisserand, revolutions of Jupiter’s fifth satellite, 331;
    • disturbance of Neptune’s satellite, 351;
    • capture of comets, 372
  • Todd, Miss M. L., drawing of corona, 268
  • — Prof., trans-Neptunian planet, 231
  • Toucani (41), 513
  • Transit circle, 198–202
  • — instrument, 202
  • — of Venus, 101, 148
  • Triangulation, 53
  • Troughton, instrumental improvements, 19, 20
  • Trouvelot, mountains of Venus, 279;
    • rotation, 280
  • Twilight, 53
  • Tycho Brahé, 5, 8, 9, 405, 418, 479, 481, 529
  • U
  • Ulugh Beigh, observations at Samarcand, 5
  • Umbra of earth’s shadow, 111
  • Uranus, discovery, 22, 229;
  • Ursa Major, stars in, 400, 401
  • Ursæ Majoris, Xi, 440
  • V
  • Variation of latitude, 136
  • Variable stars, 458
  • Vega, 403, 406, 414, 422, 427
  • Venus, phases observed by Galileo, 9;
  • Vernier, 172
  • Very, distribution of lunar heat, 295
  • Vesta, discovery, 311;
    • diameter and brightness, 312;
    • mass, 313
  • Villarceau, 433
  • Virginis, Alpha (Spica), 404, 410
  • — Gamma, 413, 444–450
  • — Tau, 456
  • — W, 469
  • Visible stars, number of, 538–546
  • Vogel, spectrum of Jupiter, 326;
    • of Uranus, 345;
    • binary or multiple system of Beta Lyræ, 466;
    • diameter of Algol, 472
  • Volcanic action, terrestrial, 284;
  • Von Gothard, 465
  • Vulpeculæ, Nova, 484
  • — S, 484
  • W
  • Ward, 488
  • Way, Milky, 402, 430, 549, 557
  • Webb, 528
  • Wedge, photometer, 213
  • Weight, defined, 151;
    • of the earth, 160
  • Wells’ comet, 368
  • Williams, A. Stanley, rotation of Venus, 280;
    • of Jupiter, 325;
    • photographs of Jupiter, 327;
    • spots on Saturn, 334
  • Wilson, Alexander, depression of sun-spots, 251
  • — W. E., temperature of the sun, 240
  • Winnecke, 422
  • Winnecke’s comet, 368, 371, 372
  • Wire micrometer, 205
  • Wolf, Max, photographic discovery of asteroids, 314;
    • comet discovered by, 377;
    • chart of the Pleiades, 499
  • Wrublewsky, 434
  • Y
  • Year, 85;
    • sidereal, 85;
    • tropical, 85;
    • leap, 86
  • Yendell, 474
  • Yerkes, 40-inch refractor, 26, 27
  • Young, solar eruption, 256;
    • spectrum of chromosphere, 258;
    • reversing layer, 258;
    • spectrum of Venus, 279;
    • brightness of Phobos, 309;
    • belts of Uranus, 343;
    • size of Uranus, 345;
    • the sun and planets, seen from Neptune, 349, 352;
    • Andromede meteors, 394
  • Z
  • Zenith, 45
  • — telescope, 210
  • Zodiac, 60
  • Zodiacal Light, 272, 273
  • Zöllner, albedo of Mars, 298, 334;
    • of Jupiter, 320;
    • of Neptune, 349;
    • estimate of sunlight, 543
  • Zone time, 84