Distances of sun and moon, relative, 68 Dog, the Greater. _See_ Canis Major; the Lesser, _see_ Canis Minor "Dog Star," 289, 297 Dollond, John, 115-116 Donati's Comet, 254, 257 Doppler's method, 125, 136, 282, 301-302 Dorpat, 117 Double canals of Mars, 214-215, 218-220 Double planet, earth and moon a, 189 Double stars, 300 Douglass, 233 "Dreams, Lake of," 197 Dumb-bell Nebula, 316 Earth, 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," 186 Earth's axis, Precessional movement of, 175-177, 295, 298-299 Earth's shadow, circular shape of, 64, 160 Eclipse, 61 Eclipse knowledge, delay of, 74 Eclipse party, work of, 73 Eclipse 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, 68 Eclipses, 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, 74-80 Eclipses of sun, 25, 65-74, Chap. VIII., 201-202, 234; 1612 A.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, 99-100 _Eclipses, Past and Future_, 340 Egenitis, 272 Electric furnace, 128 Electric light, spectrum of, 122 Elements composing sun, 144-145 Ellipses, 32, 66, 172-173, 177-178 Elliptic orbit, 66, 177 Ellipticity, 32 Elongation, Eastern, 147, 149; Western, 147, 149 Encke's Comet, 253, 256 "End of the World," 342 England, solar eclipses visible in, 87-88, 91-92 Epsilon, ([e]) Lyræ, 302 Equator, 48 Equatorial telescope, 226 Equinoxes. _See_ Precession of Eros, 210-211, 223, 226-227; discovery of, 24, 210, 227; importance of, 211; orbit of, 32, 37, 210, 336 Eruptive prominences, 139 _Esclistre_, 89 Ether, 322-323, 331-332 Europa, 233, 235 Evans, J.E., 219 Evening star, 149-150, 241 Everest, Mount, 200 Evershed, 182 Eye-piece, 110 Fabricius, 307 Faculæ, 136, 143 Fauth, 205 Faye, 335 _Fin du Monde_, 346 First quarter, 183 "Fixed stars," 280 Flagstaff, 215-216, 220 Flammarion, Camille, 346 Flamsteed, 90 "Flash spectrum," 137 "Flat," 112 Flint glass, 115 Focus, 66, 177 "Forty-foot Telescope," 115 Foster, 102 Fraunhofer, 117 French Academy of Sciences, 115 Froissart, 89 "Full moon" of Laplace, 190