261Deimos,223Deity, symbol of the,87"Demon star."SeeAlgolDenebola,296Denning, W.F.,269Densities of sun and planets,39Density,38Deslandres,140Diameters of sun and planets,31Disappearance of moon in lunar eclipse,65,102–103Disc,60"Disc" theory.See"Grindstone" theoryDiscoveries, independent,236Discovery, anticipation in,236–237;indirect methods of,120"Dipper," the,291;the "Little,"294Distance of a celestial body, how ascertained,56–58;of sun from earth, how determined,151,211Distances of planets from sun,47Distances of sun and moon, relative,68Dog, the Greater.SeeCanis Major;the Lesser,seeCanis Minor"Dog Star,"289,297Dollond, John,115–116Donati's Comet,254,257Doppler's method,125,136,282,301–302Dorpat,117Double canals of Mars,214–215,218–220Double planet, earth and moon a,189Double stars,300Douglass,233"Dreams, Lake of,"197Dumb-bell Nebula,316Earth,20,22,31,39,48,64,Chap. XV.,267;cooling of,343;diameter of,31;interior of,166;mean distance of from sun,47;rigidity of,181;rotation of,30,33,161–165,170;shape of,165;"tail" to,182"Earthlight," or "Earthshine,"186Earth's axis, Precessional movement of,175–177,295,298–299Earth's shadow, circular shape of,64,160Eclipse,61Eclipse knowledge, delay of,74Eclipse party, work of,73Eclipse of sun, advance of shadow in total,69;animal and plant life during,71;earliest record of total,84;description of total,69–73;duration of total,69,72;importance of total,68Eclipses, ascertainment of dates of past,74;experience a necessity in solar,73–74;of moon,63–65,Chap. IX.,203;photography in,93;prediction of future,74;recurrence of,74–80Eclipses of sun,25,65–74,Chap. VIII.,201–202,234;1612A.D.,90;1715,88,91;1724,88,91;1836,92;1842,92–93;1851,81,93;1868,93;1870,94;1871,94;1878,95;1882,95;1883,95–96;1893,95–96;1896,96,99;1898,96,98;1900,97;1905,75–76,80–81,97–98;1907,98;1908,98;1914,99;1927,92,99–100Eclipses, Past and Future,340Egenitis,272Electric furnace,128Electric light, spectrum of,122Elements composing sun,144–145Ellipses,32,66,172–173,177–178Elliptic orbit,66,177Ellipticity,32Elongation, Eastern,147,149;Western,147,149Encke's Comet,253,256"End of the World,"342England, solar eclipses visible in,87–88,91–92Epsilon, (ε) Lyræ,302Equator,48Equatorial telescope,226Equinoxes.SeePrecession ofEros,210–211,223,226–227;discovery of,24,210,227;importance of,211;orbit of,32,37,210,336Eruptive prominences,139Esclistre,89Ether,322–323,331–332Europa,233,235Evans, J.E.,219Evening star,149–150,241Everest, Mount,200Evershed,182Eye-piece,110Fabricius,307Faculæ,136,143Fauth,205Faye,335Fin du Monde,346First quarter,183"Fixed stars,"280Flagstaff,215–216,220Flammarion, Camille,346Flamsteed,90"Flash spectrum,"137"Flat,"112Flint glass,115Focus,66,177"Forty-foot Telescope,"115Foster,102Fraunhofer,117French Academy of Sciences,115Froissart,89"Full moon" of Laplace,190Galaxy.SeeMilky Way.Galilean telescope,109Galileo,55,109,172,197,206,232–235,242Galle,24,211,244Ganymede,233–234Gas light, spectrum of,122Gegenschein,181–182"Gem" of meteor ring,271Gemini, or the Twins (constellation),22,296–297Geminorum, ζ (Zeta),304Geometrical groupings of stars,292"Giant" planet,230,238–239Gibbous,183,185Gill, Sir David,211,258,291,317–318Gold,145Goodricke,307Gore, J.E.,63,285,303,307–308,310,323–324,331,337,347Granulated structure of photosphere,134Gravitation (or gravity),39,41–45,128,306Greek ideas,18,158,161–162,171,186,197Green (rays of light),121Greenwich Observatory,143–144,232,255,303Gregorian telescope,113–114Grimaldi (lunar crater),199"Grindstone" theory,319–322"Groombridge, 1830,"281–282,326,330Groups of stars,306–307Grubb, Sir Howard,118Gulliver's Travels,224Hale, G.E.,119,140Half moon,183,185Hall, Asaph,223Hall, Chester Moor,115Halley, Edmund,91,255,264–265,306Halley's Comet,255,264–265Haraden Hill,91Harvard,118,302Harvest moon,190–192Hawaii,221Heat rays,127Heidelberg,226,232Height of lunar mountains, how determined,201Height of objects in sky, estimation of,196Helium,138,145,182Helmholtz,128,335Hercules (constellation),295Herod the Great,101–102Herodotus,84Herschel, A.S.,269Herschel, Sir John,92,322Herschel, Sir William,22,36,114–115,204,213,235,283,292,308,319–320,326–328Herschelian telescope,114,119Hesper,109Hesperus,150Hevelius,111Hezekiah,85Hi,83Hindoos,18Hipparchus,106,177,290,311Ho,83Holes in Milky Way,321–323Holmes, Oliver Wendell,213Homer,223Horace, Odes of,106Horizon,159Horizontal eclipse,169Horrox,44,151–152Hour Glass Sea,212Huggins, Sir William,94,125,317Humboldt,270"Hunter's moon,"192Huyghens,111–112,240,242v243Hyades,296–297,307Hydrocarbon gas,254Hydrogen,94,131,138,140,144,156,182,254Ibrahimben Ahmed,270Ice-layer theory:Mars,219;moon,205,219Illusion theory of Martian canals,219Imbrium, Mare,197Inclination of orbits,36–37Indigo (rays of light),121Inferior conjunction,147,149Inferior planets,20,22,Chap. XIV.,229Instruments, pre-telescopic,106–107,172International photographic survey of sky,290–291Intra-Mercurial planet,25–26Introduction to Astronomy,31Inverted view in astronomical telescope,116–117Io,233–234Iridum, Sinus,197Iron,145,254Is Mars Habitable?221Jansen,108Janssen,94,236,258Japetus,240Jessenius,89Job, Book of,299Johnson, S.J.,103,340Josephus,101,262Juno,225Jupiter,20,22–23,31,34,37,42,227–228,230–236,241,272,311;comet family of,251–253,256;discovery of eighth satellite,26,232;eclipse of, by satellite,234;without satellites,234–235Jupiter, satellites of,26,62,108,189,232–235;their eclipses,234–235;their occultations,62,234;their transits,62,234Kant,334Kapteyn,284,313Keeler,315,337Kelvin, Lord,129Kepler,44,152,172,237,242,245,253,311Kinetic theory,156,202,212,226,231,239,336King, L.W.,84Knowledge,87Labrador,97Lacus Somniorum,197"Lake of Dreams,"197Lalande,244,283Lampland,215,219Langley,95,127Laplace,190,333Laputa,224Le Maire,115Le Verrier,24,236,243–244,275Lead,145Leibnitz Mountains (lunar),200Leo (constellation),270,295–296Leonids,270–272,274–275Lescarbault,25Lewis, T.,303Lexell's Comet,250Lick Observatory,31,98,117–118,215,232,303,305,315;Great Telescope of,117,215,237"Life" of an eclipse of the moon,80;of the sun,77–78Life on Mars, Lowell's views,217–218;Pickering's,221;Wallace's,221–223Light, no extinction of,322–324;rays of,127;velocity of,52,235–236;white,121"Light year,"53,