Undulation. A wave. Undulatory theory. The mechanical principles of the motion of waves. Vapour. Steam. the moon. The deviation of the compass needle from the true north. Vertical. The direction of the plumb-line. Vertical plane. A plane passing through the plumbINDEX. line, consequently at right angles to the horizon. Vesicles. Small hollow spheres of water. Vibration. A motion to and fro. Visual ray. A ray of light coming from any object to the eye. Volta-electric induction. The disposition of elec tric currents to produce similar currents in bodies near them capable of receiving them. ABERRATION of light, 31 39 turbed, of the spheres, 12 surement of, 54, 56 133 visions of the science of, 68, 96 130, 137, 163, 296 and repulsion, elec- capillary, 123, 125 Aurora Borealis, 172, 299, 323 -, galvanic, 305 from all substances, diffusion, 240 combustion, 241 schel, 392 164; phenomena of re- atmos- to the law of gravity, 49, 121 the, 37, 40 167; Diaphanous bodies, 213 calculated, 47, 48, 66 the theory of, 411 21,80 ; its circumference, theories, 95, 370 151 40 description of lunar, of Jupiter's satellites variation of the, 20 the, 105 153 nomena of, 151, 285 Chimborazo, Mount, 56 in, 104 heavens, 389 seq.; of the stars, 393 314 scription of Encke's and 67, 359 to 383 330 90 298 dates of, 46 sciences, conclusion, 413 revolution of, 391 308 divisions of, 98, 107 planets, 67 seq. 303, 353 340, 343 the equator, 51, 59 tumnal, 41 et Eras and chronology, 100, 103 217 356 106 219, 235, 249 157; prismatic phenome- 229, 232 radiation, 84, 228, 238; theory, 244 Sir John, 147, 195, Herschel, Miss Caroline, 398 mosphere, 171 106 146, 258, 280, 348 247, 271 104 periodic, 17 157, 184 269 by, 49, 56 17, 24; satellites of, 38, density, 96 74, 362 Inequalities, 21 tions imitated by instru- tongues, 284 103, 115, 135 gree, 57 new, Laroche's experiments in Meridian, terrestrial, 54 Meridians, whether ellipti- Metals, dilation of, 243, 300 neasuring Meteoric stones, 405, 406 Mirage of deserts, 169 netary, 13 Moon, the, 34; distance of, 62 45 luminous spots of the, 405 and earth, reciprocal influence, 10, 38, 77, 94 ; calculation of distances, 47; dimensions, 66, 68; theory of tides, 110 Mountains, deposits on, 86; height of, 131; influence, 260 Muscular strength, 134 Music, elements of, 155, 157, 159, 160; musical articu- lation, 161 Nature, the laws of, 408, Nautical Almanac, 47 Navigation, new astrono- mical aid to, 30, 46 Nebulæ ; clusters of stars, nebulous, and of great 402, 404 Newton, 1, 21, 50, 172, et the planet, 255, 392 Occultation of stars, 46 very, 222 of, 283 powers, 249 seq. |
