Spiral nebulæ, 314-316, 337-338 Spring balance, 166 Spring tides, 192 Spy-glass, 108 "Square of the distance," 43-44 Stannyan, Captain, 90 Star, mass of, how determined, 305; parallax of, first ascertained, 173, 280 Stars, the, 20, 124, 126, 278 _et seq._; brightness of, 287, 320; distances between, 326-327; distances of some, 173, 280, 320; diminution of, below twelfth magnitude, 324; evolution of, from nebulæ, 317-318; faintest magnitude of, 288; number of those visible altogether, 324; number of those visible to naked eye, 288 "Steam cracks," 221 Steinheil, 118 Stellar system, estimated extent of, 325-327; an organised whole, 327; limited extent of, 322-328, 330; possible disintegration of, 329 Stiklastad, eclipse of, 88 Stone Age, 285 Stoney, G.J., 202, 222 Stonyhurst Observatory, 100 _Story of the Heavens_, 271 Streams of stars, Kapteyn's two, 284 Stroobant, 196 Stukeley, 91 Sulphur, 145 Summer, 175, 178 Sun, Chaps XII. and XIII.; as a star, 124, 278, 289; as seen from Neptune, 246, 304; chemical composition of, 144-145; distance of, how ascertained, 151, 211; equator of, 135-136, 139; gravitation at surface of, 129, 138-139; growing cold of, 343-344; mean distance of, from earth, 47, 211; motion of, through space, 282-286, 326; not a solid body, 136; poles of, 136; radiations from, 130; revolution of earth around, 170-173; stellar magnitude of, 288-289; variation in distance of, 66, 178 Sunspots, 34, 125, 134-137, 140-141, 143-144, 308; influence of earth on, 144 Suns and possible systems, 50, 286 Superior conjunction, 147-149 Superior planets, 22, 146, 209-210, 229 Swan (constellation). _See_ Cygnus Swift, Dean, 224 "Sword" of Orion, 297, 316 Syrtis Major. _See_ Hour Glass Sea "_Systematic_ Parallax," 326 Systems, other possible, 50, 286 Tails of comets, 182 Tamerlane, 107 Taurus (constellation), 103, 296-297, 307 "Tears of St. Lawrence," 273 Tebbutt's Comet, 257-258 Telescope, 33, 55, 107-108, 149; first eclipse of moon seen through, 104; of sun, 90 Telescopes, direct view reflecting, 114; gigantic, 111; great constructors of, 117-118; great modern, 117-118 Tempel's Comet, 274 Temperature on moon, 203; of sun, 128 Temporary (or new) stars, 310-314 Tennyson, Lord, 109, 296, 334 Terrestrial planets, 229-230 Terrestrial telescope, 117 Thales, Eclipse of, 84 Themis, 240 "Tidal drag," 180, 188, 208, 344 Tide areas, 179-180 Tides, 178-180, 338-339 _Time Machine_, 344 Tin, 145 Titan, 240 Titius, 245 Total phase, 71-72 Totality, 72; track of, 66 Trail of a minor planet, 226-227 Transit, 62, 150-154; of Mercury, 62, 151, 154; of Venus, 62, 151-152, 154, 211 Trifid Nebula, 316 Triple stars, 300