atmospheres, ib.; variations in heat and light emitted from, 225, 226; amount of heat annually received by the earth from, 238; effect of his brilliancy on the heat emitted by, 259; his position affecting varia- tions in the magnetic elements, 343, 344; connexion between periodic variation in his spots and in the magnetic elements, 344; vast sweep of his gravitating force, 365; in- creased attraction of, for comets, 372; gulfs separating stars from, 390; possibility of change in his lustre, 394; spot on, measured by Sir John Herschel, 394, 395; pro- portion of his light to the moon's, 404; rate and orbit of motion with his system, 405, 406; a nebulous star, 412; meteoric nebula revolv- ing round, 422; gravitating force of, 424, 425.
Sunbeams, resolved into their com- ponent colours, 159-162; law pre- vailing in the phenomena of, 198; light a distinct property of, 214; resolved into three spectra, 222; undulations constituting, 223; their influence on vegetation, 249. Swan, the, vanishing star in, 393. Switzerland, meteors falling in, 421. Syene, arc of the meridian measured
between Alexandria and, 49. Sykes, Colonel, extensive range of cul- tivation of wheat observed by, 250. Sympathetic vibrations in musical in- struments, 147-149.
Syren, the, an instrument ascertaining the number of musical pulsations in a second, 143.
Syzigies, tides increased in the, 96.
TABLE-LANDS, high, influence of, on the atmosphere, 241. Tail of comets, sudden development
of, 372; forces producing, 375; unequal illumination of, 375, 376; change in position of, 376; divided, ib.; constitution of, 377. Talbot, Fox, his inventions in photo- graphy, 204.
Tangent, a, to planetary orbits, planets
impelled in the direction of, 8 force, disturbing, in the direction of, 14, 15; deflection from, a surement of centrifugal force, 49. Tangential force, occasioning secular inequalities, 14; effects produced by, 15; producing the variation of the moon, 35; force acting on the sea, 100.
velocity, effects produced by modifications of, 16; undiminished by the ethereal medium, 22. Telegraph, the electric, discovery leading to the invention of, 323, 324; the Atlantic, 325; principles of its construction, 326, 327; date of its completion, 327. Telegraphs, land, principle of their construction, 328.
Telescope, the achromatic, principle of its construction, 164.
the differential, differences in illumination determined by, 227. Lord Rosse's, nebulæ resolved by, 407, 415. Telescopium, comet traversing the con-
stellation of, 379; nebula in, 414. Temperature, a decrease in, affecting the earth's rotation, 72; excen- tricity of the terrestrial orbit, a cause of decreasing, 73; law equal- ising, 74; geological changes af- fecting, 75.
-, varying in the terrestrial at- mosphere, zone of constant, 119; affecting atmospheric undulations, 121; modifying the velocity of sound, 134; chemical action of light affected by, 218-222; of the ethereal medium, 227, 228; under- ground stratum of constant, 228; rate of increase in, below the earth's crust, 228, 231; of the ocean, 231; mode of finding annual aver- age, 239; causes of disturbance in regular variation of, 240-245; variations in the same latitude, 246, 247; influence of, on vegeta- tion, 248; affecting transmission of heat, 259, 260; of solid bodies, caused by absorption of rays, 268; affecting the length of the pendu-
lum, 272; causes of perpetual variations in, 274; transmission of electricity affected by, 284; affect- ing magnetism, 352. Teneriffe, the Peak of, prevailing winds on, 124; lunar heat on, 227; zones of vegetation, 250; character of its flora, 252. Terrestrial globe, the, a magnet, 336.
magnetism, 341-343; the three elements and their variations, 343, 344; storms, period of their varia- tion, 344; its connexion with solar magnetism, ib.; effect of atmo- spheric magnetism on, 345; pro- bable cause of, 346; effect of planetary magnetism on, 346, 347.
meridian, a, defined, 46. Tessular system of crystallization, 108. Texas, monsoons occasioned by its deserts, 124.
Thames, the, period occupied by the tidal wave in reaching, 94. Thaw, cause of the sensible chilliness of, 276.
Theory of probabilities, use of, in
determining astronomical data, 60. Thermo-electric currents, discovery of, 332; phenomena exhibited by, 333; principle of, applied to mea- suring heat, 333, 334. Thermography, examples of, 219-
Thermometer, the, principles applied to the construction of, 113; con- sulted in determining mountain heights, 119, 120; refraction vary- ing with, 154; heat measured by motion in, 274.
Thermomultiplier, use of, in experi- ments, 264; principle of its con- struction, 333, 334.
Theta Orionis, the multiple system of, 395.
Thibet, wheat ripening in, 250. Thomas, St., the island of, hurricane
with pauses at, 127. Thomson, W., Professor, experiments of, in freezing water, 271; dyna- mical theory of heat maintained by, 275 note; his calculation of the force exerted in vibrations of
light, 279; investigation into the relations of light and magnetism, 320; density of the ethereal me- dium computed by, 356; magnetic property of the ethereal medium pleaded for, 357.
Thunder, theory of prolonged peals of,
Tidal wave, theory of, 92; its birth- place, 93; course of, 93, 94; velocity, 94; effect of depth on its motion, 95.
Tides, calculation from the moon's action on, 55; theory of forces producing, 91, 92; circumstances occasioning irregularities, 93; ris- ing, progress of, 93, 94; three kinds of oscillations in, 95, 96; variations in, from lunar and solar influence, 96-98; effect of inter- ference of waves on, 99; the sea's equilibrium under anged by, 100.
lunar and diurnal, of the ter- restrial atmosphere, 121; examples of sympathetic undulation, 148. Time, a measure of motion, 58; a measure of angular motion, 83; difference between mean and ap- parent solar, 84; mean equinoctial, mode of computing its object, 86; estimation of, corrected by means of laws of unequal expansion, 272. Timocharis, comparison of his obser- vations with Hipparchus, 80.
Tomboro, submerged in a volcanic eruption, 233.
Torpedo, the, electrical action of, 310,
Torrecelian vacuum, experiment on the electric discharge in the, 306; lines of magnetic force passing through, 344,
Torronto, observations on magnetic storms at, 346.
Toucan, comet approaching the con-
stellation of, 379; a nebula in, 414. Toucani, 47; globular nebulous clus- ter, 414. Tourmaline, brown, light polarized by prisms of, 180; property quali- fying it to analyze polarized light, 182; coloured images produced by,
186, 187; changed by compression, 189; heat polarized by, 265; elec- tricity communicated to, 284. Trade winds, friction of, not affecting
the earth's velocity, 72; action on the general motion of the sea, 100; system of, accounting for atmo- spheric anomalies, 120; theory of their origin, phenomena con- nected with, 122, 123; becoming monsoons, 124.
Transits of Venus, 52, 53.
two consecutive, of any star, a measure of time, 83. Transmission of radiant heat, 258, 262; of electricity, 284, 285; of voltaic electricity, 298; molecular structure affecting, 303; method of, determining the influence of electric currents, 317; of gravity, an unsolved question, 355; pro- bable agent, 356; medium of, in space, 424. Transparent bodies, temperature of,
unaffected by the sun's rays, 227. Trees, number of species of forest, found in America and Europe, 252. Tribes, apparently distinct, of the human race, 255.
Triple stars, 395; periods of revolu- tion in, 400.
Tropical year, change in its length, 80; period of, 83; difficulty of adjusting its estimation, 85.
revolution of the major axis of the solar ellipse, its period, 86. vegetation, the luxuriance of,
Tuileries, clock in the, showing deci-
Twilight, caused by refraction, 154;
effect of reflection, 158. Tyndall, Professor, his experiments proving diamagnetic polarity, 348; on magnetic action in crystals, 349.
UNDULATIONS, theory of, 99; of the atmosphere, 121, 122; of the waves of sound, 129, 130; inter- vals produced by interference, 139; giving musical notes, 142, 143; sympathetic, 147, 149; of the
luminous ether, 169, 170; in re- fraction and reflection, 177; pro- ducing fluorescence, 197; different, in light and sound, 199, 200; con- stituting a sunbeam, 223; heat propagated by, 267; of light, evolu- tion of latent force in extinguished, 279, 280; of natural forces identi- cal, 281. Undulatory theory of light, 168-170; law of motion affecting, 176, 177; phenomena proving, 198; objection, from the different action of light and sound, refuted, 199; proving the existence of the ethereal medium, 358; acceleration in comet's mo- tion proving, 367.
theory, experiments determin- ing in favour of, 200, 201; final and decisive experiment, 202; of heat, 267.
Unison, note in, 142.
United States, astronomical observa- tions made in, 371, 373. Uranium, phosphorescent property of,
296; peculiar luminous properties of, 296.
Uranus, effect of reciprocal attraction between Neptune and, 22; periods of the revolutions of his satellites, 33; distance from the sun, 54; astronomical tables of, 60; disco- very suggested by his perturbations, 61; observations on, leading to Neptune's discovery, 62; sun's in- fluence in, 225; action of, on Hal- ley's comet, 363; appearance of the sun to, 380, 381; comets in his orbit, 381, 382.
Ursa Major, periodic time of a double star in, 398; nebulous region of, 417. Utah, deserts of, causing monsoons, 124.
VACUUM produced by shell-fish, 117 ; existing in the air, 118. Valz, M., telescopic planet discovered by, 21; comet observed by, 358; observations on a comet's approach to the sun, 364; cause assigned by, for contraction in diameter of comets, 377, 378.
Vapour, formation and dispersion of, 269, 270; force developing, 277. Variable stars, periodic fluctuation of lustre in, 390, 391; new, appear- ing and vanishing, 392, 394; miss- ing, 395.
Variables, region of the, 122. Vegetation, effect of, in lowering tem-
perature, 243; the two requisites for, 248; strength and vitality of, 249; chemical action of light in- fluencing, ib.; laws of its distribu- tion, 249-252; distribution of marine, 252, 253; theories of specific diversity of original distri- bution of, 253, 254.
Veitch, James, comet with luminous
rings discovered by, 374, 375. Venus, zone of instability between
the sun and, 21; perturbation in the mean motion of the earth and, 26; eclipsing Mercury, 42; tran- sits of, parallaxes calculated from, 52, 53; astronomical tables of, 63; climate, 226.
Vernal equinox, planetary motions estimated from, 9.
Vesta, astronomical tables of, 63; no atmosphere surrounding, 226. Vesuvius, revived volcanic action of, 234.
Vibrating plates used in experiments
on musical sound, 144, 147. Vibrations of the air producing sound, 129; in music, 131; number made by the human voice in a second, 132.
of the ether in natural and po- larized light, 193; in fluorescence of light, 196; plane of, in polarized light, 223.
Vico, Padre de, comet discovered by, 370.
Vienna, observations on comets from, 370.
Viviers, transit of a comet across the sun observed from, 374. Volcanic regions of the globe, 232 annual number of eruptions, 233; celebrated eruptions, ib.; earth- quakes caused by, 234; supposed causes of action, 235; Sir John Herschel's theory, 235-237. Volta, Professor, electricity rendered manageable by, 297; the world's debt to, 328.
Voltaic electricity, first suggestions of, 297; theory of the transmission of, 298; construction of the bat- tery, 298, 299; theory of its pro- duction, 300; characteristic pro- perties, 300, 301; action of, gene- rating heat and light, 301-303; arc, experiments, 303-305; the, discharge oxidizing silver, 305, 306; stratified light, 306, 307; chemical decomposition effected by agency of, 307, 308; crystalliza- tion, 308; an agent in the fine arts, 309; conductors of, ib.; relations of heat and, 310; fish producing effects of, 310, 311; science sug- gested by its influence on a mag- netized needle, 312; rotation ef- fected by, 313, 314; inducing magnetism, 314, 315; distinction between static electricity and, 317; unvarying dual force of, 334. Voltaic pile, the, invention of, 297; perfected, 298-300.
Vortices, molecular, theory of, 104. Vosges mountains, temperature of mines in the, 228. Vulpecula, nebula in, 409.
WARDHUS, transit of Venus observed at, 53. Watches, irregular action of, corrected by the laws of unequal expansion, 272. Water, constituent parts of, 111; boiling point of, an estimate of mountain heights, 120; as a me- dium for sound, 135; light polar- ized circularly by, 194; experiment deciding the velocity of light in, 202; law of expansion of, 271;
process of congelation, 276; boil- ing points of, 277; decomposed by electric agency, 307; as an electric conductor, 309; rotating by elec- tricity, 314.
Waterspouts, origin and cause of, 128. Waterstone, Mr., magnetic property
of the ethereal medium maintained by, 357.
Waves neutralized by interference, 99. —, atmospheric, over local districts, periods, dimensions of, 121, 122.
of sound, 131; furnishing an illustration of reflections of sound and light, 137; interference of, pro- ducing calm, 139.
Wedgwood, Dr., attempts of, to trace
objects by means of light, 203, 204. Week, the, of seven days, the most ancient and universal division of time, 85.
Wells, increase of temperature in, 230, 231.
Welsh, Mr., observations made by, in a balloon ascent, 119.
West Indies, the, cause of hurricanes in, 126.
Wheels invented to test intensity of sound, 132, 133.
Wheat, range of its cultivation, 250. Wheatstone, Professor, experiments in acoustics of, 132; musical instru- ments invented by, 143; paper on musical vibrations read by, 145; experiments on sounding boards of, 150; experiments on sound rein- forced by resonance, 151; instru- ment measuring velocities of elec- tricity and light invented by, 202; spectrum of an electric spark ob- served, 289; speed of electricity measured, 289, 290; experiments on the spectrum of Voltaic flame, 303.
Willis, Mr., articulating machine in-
vented by, 151; investigations of, into the mechanism of the larynx, 152. Winds, trade, 122, 123; monsoons, 124; extra-tropical, in the North Atlantic, ib.; currents above the trade winds, 124, 125; pheno-
mena of rotatory motion, 125; hurricanes, 125, 128; agency of, in- fluencing temperature, 244, 245. Wines, range of cultivation of the best, 250.
Winter, atmospheric electricity in, 291.
mean temperature of, varying in the same latitude, 246, 247. Wolf, Professor, periods of variation in solar heat computed by, 225. Wollaston, Dr., experiments of, on sensitiveness to sound, quotation from, 132; experiment of, to show the effect of variable media on re- fraction, 156; discovery of rayless lines in the solar spectrum, 162; observations of, on the chemical properties of the solar spectrum, 203, 209; magnetic rotation sug- gested by, 313; light emitted by the heavenly bodies calculated, 404.
XI Ursæ Majoris, periodic time of, 398; velocity of the revolving star, 400.
YEAR, a, in Jupiter and Saturn, 66; tropical change in its length, 80; length of the sidereal, ib.; period of the mean, 83; estimation of the Egyptian, 85; first of our era, 86; length of the, affected by a comet's passage, 359.
Young, Dr., his calculation of the possible compression of solids, 78; 'date of a horoscope determined by, 89; density of a liquid column estimated by, 114; exception ad- duced by, to a general law in acoustics, 137; his theory of the pleasures of harmony, 142; undu- latory theory established by, 169; data used by, to test his theory of light, 175; illustration of, proving sound and heat kindred forces, 280, 281.
ZETA Cancri, a triple star, 395; periodic time of, 398; revolution, 400; colours, 401.
« PreviousContinue » |