Alexander, structure of the Milky Way,214Amœba, versatile organization,274-5Anaximander, generalized matter,5Anaximenes, air as the 'Urstoff,'4,151Aristotle, conception of nature,8;solid spheres,13Asteroids, orbital relations,236Babinet, objection to Laplace's cosmogony,44Bacon, elemental triad,151Ball, Sir Robert, mechanics of a condensing nebula,79,209-10Barnard, discoveries of nebulæ,212;observations of the Gegenschein,259Becquerel, detection of radio-activity,157,162Bessel, astronomy of the invisible,141Bode's law of planetary distances,26Brorsen, the zodiacal counterglow,259Bruno, a platonic pantheist,9Buffon, cometary impacts,61;fossil foraminifera,275Campbell, system of ζ Geminorum,113;number of spectroscopic binaries,143;density of nebulium,153Chladni, meteoric cosmogony,118Comets, position in Cartesian system,12-13;in that of Laplace,136;origin,73-4,252-4;meteoric relations,122-4,133;solar dependants,133,140,236,251;nebular affinities,137,254-5;insignificant mass,242Cosmogony, primitive,1-3,14;philosophical,3-7;scientific,7,15;of Descartes,11-13,60;Kant's,21-28,61-2,252,254;Laplace's,29-33,38-53,57-61,138,235;Herschel's,35-7,136,199-201;Faye's,68-76,81,129;Lockyer's,125-134;sidereal,105-7,145-7,217-230Crookes, Sir William, protyle,5,149;radiant matter,154,156-7;future of the world,163Curie, Madame, discovery of radium,162Dalton, combining equivalents,152Dark stars,141,226-7Darwin, condensation of nebulous rings,42,51;history of earth-moon system,87-92,94,97,142;equilibrium of rotating globes,102,104-5,112,143;fluid pressure on meteor-swarms,129,131;spiral nebulæ,205Delambre, on cosmic speculations,14,15Democritus, mechanical theory of the world,5,22Descartes, theory of vortices,11-13Dissipation of energy,229Double stars, genesis and development,98-9,106-7,142-5,226-7;occulting,108-113;variable,113-115,143;'dumb-bell' type,115,116,143;frequency of occurrence,144,234Earth, effective rigidity,86;critical situation,87;antique disruption,89,91;tidal effects upon,90,244;meteoric intakes,119-120,133;internal heat,266Easton, the galactic spiral,214Eclipses, stellar,107-8;questionable occurrence,109-113;criterion of reality,114Electricity, discharge through vacua,154;relations with disintegrated matter,155,159-160,163;gravity explained by,177-8,179;dual properties,180-181;fundamental in nature,182;ethereal transmission,185Electrons, copious production,174;strain-centres,189-190,195;ultimates of matter,231Elements, ancient and mediæval ideas regarding,5,151;genesis,152,230-231Empedocles, four elements,5,151Ether, in Cartesian philosophy,12;evasive character,159,183,197-8;relation to gravity,175,185;properties,184,191,193-4Evolution, of solar system,22,241,250;of stars,35-6,217-225;of stellar systems,98-9,106-7,142-5,226-7;of nebulæ,145-6,200-211;of the chemical elements,151,230-231Faye, objections to Laplace's cosmogony,25;modified scheme,68-73,81,129;duration of the sun,76Fleming, nature of electrons,195Frost and Adams, spectroscopic binaries,143,221Galileo, first law of motion,12Goldstein, cathode-rays,155Gravitation, mode of action,168,185;velocity of transmission,169,175,177;explanatory hypotheses,170-179Hale, relationships of carbon stars,225Halley, nature of nebulæ,36Hansky, status of zodiacal light,261Harvey, life from life,268Helium, present in the sun,55;origin by atomic decay,158,230;absorption in stars,220,222-3;a constituent of nebulæ,230Helmholtz, maintenance of solar heat,31,34,35,74-5Helmont, spontaneous generation,268Heracleitus, elemental evolution,151Herodotus, omnipotence of time,269Herschel, Sir John, nature of atoms,156;Saturn's satellites,240Herschel, Sir William, Uranian system,29;sidereal evolution,35-6,37,136;observations of nebulæ,199;history of their growth,200-201Huggins, Sir William, discovery of gaseous nebulæ,54,153Huggins, Sir William and Lady, stellar development,226Huxley, origin of life,269,271,272Hydrogen, molecular velocity,55;the unit-atom,152;tenuity,153;absorption in stars,221-2Island-universes,54Jeans, figures of equilibrium,104-5;nature of radio-activity,196Jupiter's system,240-1Kant, cosmological speculations,20-28,60-62,252,254;tidal effects,27,84-5;Saturn's rings,49;status of comets,73Kelvin, Lord, Lesage's theory of gravitation,174;vortex-atoms,187;dissipation of energy,229;origin of life,268,280Kepler, physical astronomy,10Kirkwood, objection to nebular hypothesis,50,51;effects of solar tidal friction,67Lambert, sidereal construction,17-18Langley, mass of meteoric infalls,119Laplace, hypothesis of planetary origin,25,29-31,33,36-42,52-3,58-9,60-62,235;Saturn's ring-system,49;Mécanique Céleste,57;status of comets,73,136Larmor, scheme of molecular physics,188;definition of ether,189,193Lenard, cathode-rays,157Lesage, rationale of gravity,172-3,175Lewis, masses of double stars,226Ligondès, scheme of planetary growth,77-8,81,252;comets as survivals,253,256Lockyer, Sir Norman, meteoritic hypothesis,125-7;enhanced lines,223Lorentz, electrical hypothesis of gravity,177-8,185Magellanic clouds, spiral conformation,213Marchand, plane of the zodiacal light,263Mars, rotation of,47-8Maxwell, origin of matter,161;corpuscular theory of gravitation,173Mayer, J. R., effects of tidal friction,87Mercury, action upon of solar tides,88,96;eccentric orbit,242Meteoritic formation of planets,28-9,119-122,125,128,131-3;of comets,122-4;of nebulæ,126-7,134Meteors, abundance,119,133;mineralogy,121-2,134;hyperbolic orbits,133;attendance on the sun,236Meteor-swarms, progressive dispersal,72,124;constitution,122-4,128-131;primitive existence,134Milky Way, theories regarding,16-17,215;undeveloped condition,201,207;relation to sun's movement,247Mohl, protoplasm,270Moment of momentum,23,40,44,45,65,209Moon, origin,87-92,97,139,145;retreat from the earth,244Moulton, nebular cosmogony,44,51,82Myers, systems of β Lyræ and U Pegasi,109-110Nebulæ, gaseous composition,37,153,201,205;illusory resolution,53;spiral structure,79-80,106,146,190,204-208,211-214;classification,199;development,200-202,205,207-211;relation to stars,202-3,205;helium ingredient,230,255Nebular hypothesis, propounded by Kant,22-8;by Laplace,29-31,38,52-3,61;difficulties,39-52,54-6;amendments,60-82Nebulium, a constituent of nebulæ,54,153,201Neptune, retrograde system of,43,52,237Newcomb, transverse observation of the zodiacal light,260Newton, transmission of gravity,184,185Nova Persei, nebulous appurtenance,206Perrine, new Jovian satellites,240Pezénas, notice of the counterglow,259Phobos, anomalous revolution,47-8,237Phœbe, retrograde motion,96,237-8Pickering, E. C., binary nature of V Puppis,112;structural relations of the Looped Nebula,213Pickering, W. H., origin of Phœbe,97,238;photograph of a great nebula,212;satellite discoveries,237,240Plato, conception of a world-soul,8Poincaré, rotational equilibrium,101,105,110,143;destiny of the solar system,243-4Prestwich, Laurentian graphite,279Proctor, structure of the Milky Way,214Protoplasm, its properties,270-273Protyle, supposed discovery,149,154-7;function and qualities,152;cosmic relations,164-5Prout, unity of matter,152Radio-activity, possible effects,33-4,229;discovery,157;nature and cause,158-9,162-3,196Red stars, affinities,224-6Redi, transmission of life,268Reynolds, explanation of gravity,170;molecular physics,188,192-3Richter, germ-laden aerolites,280Roberts, A. W., systems of R2Centauri and of V Puppis,111,113Roberts, Isaac, spiral arrangements of stars,214Roche, planet-making expedients,48;reconstruction of Laplace's hypothesis,62-67Roche's limit,63,115-6Röntgen rays, discovery,157;ethereal nature,158,176;electronic effects,163;suggested connection with gravity,176Rothmann, early notice of the zodiacal light,256Russell, photographs of Magellanic Clouds,213Rutherford, atomic disintegration,162Satellites, periods of revolution,46;anomalies of movement,47-8,52,96,236-9;effects on of tidal friction,93-4,96,97,238;origin by fission,105;'asteroidal,'239-40Saturnian system, an example to cosmogonists,41,71;anomalies,49,52,96,237-240Schaeberle, photographs of nebulous spirals,204,212Secchi, star-classification,219See, tidal friction in stellar systems,98,142Shelley's Demiorgon,9Solar system, origin,22,39-42,69-82,241;anomalies,29,43-52,236-241;mechanism,30,234-5;stability,235,242;springs of decadence,243-5;translation,245-8Spectroscopic binaries,98,112-114,142-4,221Spencer, status of nebulæ,54;spontaneous generation,270Spinoza, pantheistic views,9Stars, relations to nebulæ,35-6,202-3;distribution,147;relative ages,217-221,225;spectra,221-5Stokes, Sir George, nature of life,276Stoney, criticism of gravitational hypothesis,179Sun, mode of development,25,31;maintenance of heat,31-5;helium-constituent,55-6;stellar relationships,224-5;actual standing,232-3;motion in space,245-8Swedenborg, cosmic evolution,4,6,15Thales, ideas of cosmic evolution,4,14,151Thomson, J. J., mass of corpuscles,158;gravitational effects,173;Röntgen rays and gravity,176;ether and matter,190Tidal friction, effects in earth-moon system,28,87-92,94,97,244;in other sub-systems,48,50,93-7,238-9;on binary stars,98-9,108,142;modifying power,46-7,67-8,83-7Tisserand, transmission-rate of gravity,175Uranian system, retrograde motion,43,52,70,237Variable stars,108-115Venus, mode of rotation,96Vogel, stellar development,219,225Whewell, status of nebulæ,54Whittaker, undulatory theory of gravity,178-9Wilson, radium in the sun,34Wolf, C., motion of Phobos,48;solar tidal friction,67;criticism of Faye's cosmogony,73Wolf, Max, photographs of the zodiacal light,263World Soul, function in cosmogony,8-9Wright, theory of the Milky Way,16-17,18,20Zodiacal light, origin,256-7,261,264;triple aspect,257-60;transversal dimensions,260;constitution,262;plane of extension,262-3