Achromatictelescope,115,116Adams,24,236,243Aerial telescopes,110,111Agathocles, Eclipse of,85Agrippa, Camillus,44Ahaz, dial of,85Air,166Airy, Sir G.B.,92Al gûl,307Al Sufi,284,290,296,315Alcor,294Alcyone,284Aldebaran,103,288,290,297Algol,307,309–310,312,323,347Alpha, Centauri,52–53,280,298–299,304,320Alpha Crucis,298Alps, Lunar,200Altair,295Altitude of objects in sky,196Aluminium,145Amos viii. 9,85Anderson, T.D.,311–312Andromeda (constellation),279,314;Great Nebula in,314,316Andromedid meteors,272Anglo-Saxon Chronicle,87–88Anighito meteorite,277Annular eclipse,65–68,80,92,99Annular Nebula in Lyra,315–316Annulus,68Ansæ,242–243Anticipation in discovery,236–237Apennines, Lunar,200Aphelion,274Apparent enlargement of celestial objects,192–196Apparent size of celestial objects deceptive,196,294Apparent sizes of sun and moon, variations in,67,80,178Aquila (constellation),295Arabian astronomers,107,307Arago,92,257Arc, degrees minutes and seconds of,60Arcturus,280,282,290,295Argelander,290Argo (constellation),298Aristarchus of Samos,171Aristarchus (lunar crater),205Aristophanes,101Aristotle,161,173,185Arrhenius222,253–254Assyrian tablet,84Asteroidal zone, analogy of, to Saturn's rings,238Asteroids (or minor planets),30–31,225–228,336;discovery of the,23,244;Wolf's method of discovering,226–227Astrology,56Astronomical Essays,63,337Astronomical Society, Royal,144Astronomy, Manual of,166Atlantic Ocean, parallelism of opposite shores,340–341Atlas, the Titan,18Atmosphere, absorption by earth's,129–130;ascertainment of, by spectroscope,124–125,212;height of earth's,167,267;of asteroids,226;of earth,129,130,166–169,218,222,267,346;of Mars,156,212,216;of Mercury,156;of moon,70–71,156,201–203;of Jupiter,231;of planets,125;of Saturn's rings,239"Atmosphere" of the stars,331Atmospheric layer and "glass-house" compared,167,203August Meteors (Perseids),270Auriga (constellation),294–296,306,311;New Star in,311Aurigæ, β (Beta),294,297,304Aurora Borealis,141,143,259Australia, suggested origin of,340Axis,29–30;of earth,163,180;small movement of earth's,180–181Babyloniantablet,84Babylonian idea of the moon,185Bacon, Roger,108Bacubirito meteorite,277Bagdad,107Baily, Francis,92"Baily's Beads,"69,70,91–92,154Bailly (lunar crater),199Ball, Sir Robert,271Barnard, E.E.,31,224,232–234,237,258"Bay of Rainbows,"197Bayer's classification of stars,289,291–292Bayeux Tapestry,263Bear, Great (constellation).SeeUrsa Major;Little,seeUrsa MinorBeehive (Præsepe),307Beer,206Belopolsky,304"Belt" of Orion,297Belt theory of Milky Way,321Belts of Jupiter,230Bergstrand,314Berlin star chart,244Bessel,173,280,305Beta (β) Lyræ,307Beta (β) Persei.SeeAlgolBetelgeux,297Bible, eclipses in,85Biela's Comet,256–257,272–273,345Bielids,270,272–273Billion,51–52Binary stars, spectroscopic,301–306,309;visual,300,303–306"Black Drop,"152–154"Black Hour,"89"Black Saturday,"89Blood, moon in eclipse like,102Blue (rays of light),121,130Bode's Law,22–23,244–245Bolometer,127Bond, G.P.,236,257Bonpland,270Boötes (constellation),295,314Bradley,111Brahe, Tycho,290,311Brédikhine's theory of comets' tails,253–254,256Bright eclipses of moon,65,102British Association for the Advancement of Science,318British Astronomical Association, Journal of,194British Museum,84Bull (constellation).SeeTaurus;"Eye" of the,297;"Head" of the,297Burgos,98Busch,93Cæsar, Julius,85,110,180,259,262,291,293Calcium,138,145Callisto,233–234Cambridge,24,91,119,243Campbell,305Canali,214"Canals" of Mars,214–222,224–225Cancer (constellation),307Canes Venatici (constellation),306,314Canis Major (constellation),289,296–297;Minor,296–297Canopus,285,298–299,320Capella,280,282,290,294,297,303,313Carbon,145Carbon dioxide.SeeCarbonic acid gasCarbonic acid gas,166,213,221–222Carnegie Institution, Solar Observatory of,118Cassegrainian telescope,114,118Cassini, J.D.,236,240"Cassini's Division" in Saturn's ring,236,238Cassiopeia (constellation),279,294,311,314Cassiopeiæ, η (Eta),303Cassiopeia's Chair,294Cassius, Dion,86Castor,282,297,304Catalogues of stars,106,290–291,311Centaur.SeeCentaurusCentaurus (constellation),298,306Centre of gravity,42,283–284,324Ceres, diameter of,30,225Ceti, Omicron (or Mira),307–308Cetus, or the Whale (constellation),307Chaldean astronomers,74,76Challis,243–244Chamberlin,337"Chambers of the South,"299Chandler,308Charles V.,261"Charles' Wain,"291Chemical rays,127Chinese and eclipses,83Chloride of sodium,122Chlorine,122,145Christ, Birth of,102Christian Era, first recorded solar eclipse in,85Chromatic aberration,110Chromosphere,71–72,93–94,130–132,138–139Circle,171–173Clark, Alvan, & Sons,117–118,303Claudius, Emperor,86Clavius (lunar crater),199Clerk Maxwell,237"Clouds" (of Aristophanes),101Clustering power,325Clusters of stars,300,306,314,328Coal Sacks.SeeHoles in Milky WayCœlostat,119Coggia's Comet,254Colour, production of, in telescopes,109–111,115,121Collision of comet with earth,345–346;of dark star with sun,346–348;of stars,285,312Columbus,103Coma Berenices (constellation),307,316Comet, first discovery of by photography,258;first orbit calculated,255;first photograph of,257–258;furthest distance seen,258;passage of among satellites of Jupiter,250;passage of earth and moon through tail of,257,346Comet of 1000A.D.,262;1066,262–264;1680,255,265;1811,254–255;1861,254,257,346;1881,257–258;1882,251,258,291;1889,258;1907,258Comets,27–28,58,Chaps. XIX.andXX.,345–346;ancient view of,259–261;captured,251–253;Chinese records of,83–84;composition of,252;contrasted with planets,247;families of,251–252,256;meteor swarms and,274;revealed by solar eclipses,95–96;tails of,141,182,248,252–254Common, telescopes of Dr. A.A.,118Conjunction,209Constellations,105,278–279,285,289Contraction theory of sun's heat,128–129,335Cook, Captain,154Cooke,118Copernican system,20,107,149,170–173,279,280Copernicus,20,108,149,158,170–172,236Copernicus (lunar crater),200,204Copper,145Corder, H.,144Corona,70–72,90,92–97,132,140–141,270;earliest drawing of,91;earliest employment of term,90;earliest mention of,86;earliest photograph of,93;illumination given by,71;possible change in shape of during eclipse,96–98;structure of,142–143;variations in shape of,141Corona Borealis (constellation),295Coronal matter,142;streamers,95–96,141–143Coronium,133,142,317Cotes,91Coudé, equatorial,119Cowell, P.H.,255,264Crabtree,152Crape ring of Saturn,236–237Craterlets on Mars,220Craters (ring-mountains) on moon,197–205,214,340;suggested origin of,203–204,214Crawford, Earl of,94Crecy, supposed eclipse at battle of,88–89Crescent moon,183,185Crommelin, A.C.D.,255,264Crossley Reflector,118,315–316Crown glass,115Crucifixion, darkness of,86Crucis, α (Alpha),298Crux, or "Southern Cross" (constellation),298–299,323Cycle, sunspot,136–137,141,143–144Cygni,61,173,280Cygnus, or the Swan (constellation),295,325Daniel'sComet of 1897,258Danzig,111Dark Ages,102,107,260Dark eclipses of moon,65,102–103Dark matter in space,323Dark meteors,275–276Dark stars,309–310,312,323,346–347"Darkness behind the stars,"325Darwin, Sir G.H.,339Davis,94Dawes,236Dearborn Observatory,303Death from fright at eclipse,73Debonnaire, Louis le,88,