/a>; the true, 224. —— terrestrial, solar rays bent by, in lunar eclipses, 40; - influence of, in solar eclipses, 41;
- its analysis, pressure on the surface of the globe, 117;
- form of, gradual decrease in density of its strata, 117, 118;
- influence of temperature on its density, 119;
- mean pressure of, variable, 120;
- the medium conveying sound, 129;
- sympathetic vibrations transmitted by, 147, 148;
- its action on light, falsifying vision, 153;
- phenomena produced by accidental
- changes in its strata, 155-156;
- effects of increased density in the stratum in the horizon, 157, 158;
- lunar heat absorbed by, 227;
- cause of the cooler air in higher regions of, 240, 241;
- sun’s heat modified by, 244;
- action of electricity in, 284;
- transmission of electricity by induction, 286;
- periodical variations of electricity in, 291;
- accidental developments of electricity, 291, 292;
- cause of variations in its magnetism, 344, 345;
- nebulous bodies made visible by, 421-423.
Atmospheric air, extreme elasticity of, 105. —— pressure, effect of, on electricity, 288. Atomic constitution determining crystalline forms, 109. Atoms, qualities of, determining the nature of substances, 110; - differences in weight of, 111.
Attraction, modes of, in spheres, in the celestial bodies, 4; - determining the forms of planets, 6;
- determining the motions of planets, 7;
- solar, compelling the elliptical revolutions of planets, 8;
- mutual, of planets, complicating their motions, 10;
- interference of, disturbing the motions of heavenly bodies, 11;
- disturbances from the operation of reciprocal, 13;
- disturbances from inequality of, 14;
- of satellites to primaries, little disturbed, 26;
- disturbing force of, in spheroids, 27;
- its effects on Jupiter’s satellites, 28;
- sun’s, of the moon, 34;
- principle modifying the earth’s, 37;
- local, affecting the plumb-line, 48;
- comparative force of the sun’s, 57;
- of an external body affecting a spheroid, 79;
- producing tides, 91, 92;
- of particles of matter, 103;
- capillary, 113;
- producing annual atmospheric undulations, 121;
- the lunar atmosphere affected by, 226;
- expansive force of heat overcoming, 271;
- of electricities, Brand, M., observation of, on meteors, 423.
- Brewster, Sir David, his analysis of the solar spectrum, 71;
- period of the mean sidereal and solar, 83;
- varying with the seasons, 84;
- decimal division of, 84;
- seven, the most permanent division of time, 85.
- Deccan, the, wheat ripening in, 250.
- December, 1832, disappearance of Saturn’s rings in, 67;
- coincidence of mean and apparent time in, 84;
- date of Christ’s nativity, 85;
- the astronomical year beginning in, 86.
- Decimal division of time, 84.
- Declinations of the moon, 97.
- Decomposition, effected by electricity, 307-308;
- by magnetism, 323;
- by thermo-electricity, 333.
- Delambre, his computations of the length of the year, 359.
- Delta Cephei, a variable star, 391.
- Denmark, course of the tidal wave to, 94.
- Density, variable, impeding sound, 135, 136:
- of media, modifying refraction, 153.
- Densities of heavenly bodies, formula finding, 56;
- experiments, 57, 58;
- comparative of the terrestrial globe, 77, 78.
- Deserts, causing monsoons, 124;
- influence of, on temperature, 243.
- Dew, cause of its deposition, 269.
- Diamagnetic substances, 335, 336.
- Diamagnetism defined, 335;
- substances it is resident in, 336;
- discovery, characteristics of, 347;
- neutral substances obtained by proportionate combination of, with paramagnetism, ib.;
- polarity of, 348;
- connected with arrangement of molecules, 350-351;
- affected by division and compression, 351;
- possibly identical with paramagnetism, 356, 357.
- Diameter of the earth, 21;
- Jupiter’s polar, 27;
- excess of his equatorial, 39;
- apparent, of the sun and moon, nearly equal, 40;
- of the earth, 49;
- of bodies composing the solar system, 56;
- of Neptune, 63;
- comets lacking a sensible, 373;
- contraction of, in comets, 377;
- causes assigned for, 377, 378.
- —— of an annular nebula, 410;
- sensible, of a planetary nebula, 412.
- Diamond, the, polarized light reflected from, 193.
- Dielectrics in electricity, 286.
- Dieppe, seen from Hastings, 157.
- Differential telescope, the, experiments to be made by, 217;
- communicated to metal plates by juxtaposition, 220;
- impressions traced on glass by, 221;
- rays exciting, 223;
- a dual power, 282;
- modes of exciting by disturbing equilibrium, 282-284;
- transmission of, 284, 285;
- transmission by induction, 285, 286;
- laws of attraction and repulsion determining intensity of, 286-288;
- heat and light produced by, 288;
- velocity of, 289;
- experiment determining its velocity, 290;
- development of, in the atmosphere, 291, 292;
- phosphorescence excited by, 294;
- Voltaic, see Voltaic;
- conduction of static, contrasted with Voltaic, 309;
- laws of action in, distinguishing it from Voltaic, 317;
- relation between 322, 323;
- telegraphs working by, 323-328;
- produced by rotation, 330, 331;
- thermo, 332, 333;
- exact balance of its dual force, 334;
- points of analogy between magnetism and, 340, 341;
- causing convulsions in comets, 375.
Electro-dynamics, see Dynamics. —— magnetism, see Magnetism. Elements, the three terrestrial magnetic, 343; - variations in, ib.;
- storms affecting, 344.
Elevation, effect of, on temperature, 240-242; Ellipses, described by planets, 5; - paths of planets describing, 10;
- preventing compensation of disturbance, 15;
- cause and measures of variation in, 17;
- described by comets, 363, 366.
Ellipsoid, an, of revolution, mass assuming the form of, 45; - its equatorial and its polar radius, 48;
- permanent axes of rotation, 76.
Elliptic motion, ratio of forces procuring, 382. Elliptical polarization of light, 192, 193; —— nebulÆ, 409; - their connection with double stars, 411;
- frequency, 413;
- difficult of resolution, 415.
Encke, Professor, sun’s parallax found by, 53; - his comet, 169;
- aspects, period of his comet, 365, 366;
- cause of acceleration in its revolution, 366, 367;
- crossing the t
ef="@public@vhost@g@html@files@52869@52869-h@52869-h-15.htm.html#Page_92" class="pginternal">92, 93;
- law, universally acting on matter, 105;
- the air subject to, 117;
- influence of, in motions of the heavenly bodies, 382, 383;
- double stars revolving by, 398;
- stellar systems subject to, 400;
- influence of, on nebulÆ, 416;
- a general law of the visible creation, 424;
- mode of its action, 425, 426.
Gravity, centre of, in spheres, effect of impulses passing through, 7; - of the solar system, invariable plane passing through, 23;
- straight line described by, 24;
- action of, in determining the figure of the earth, 44, 45;
- definition irreconcilable with the conservation of force, 354, 355;
- question of its transmission, 355, 356.
Great Bear, the nebulous zone passing, 416. —— Gobi, the, effect of the expansion of air over, 124. Greeks, astronomical observations of, confirming results of analysis, 38. Greenland, ocean on the northern coast of, 94. Greenwich, lunar distances computed for, 43; - quadrant of the meridian passing through, furnishing a unit of linear measure, 89;
- periodic circuits of winds, 125.
Grimaldi, coloured fringes bordering shadows described by, 175. Groombridge, velocity of his proper motion, 404. Grotthus, the transmission of voltaic electricity investigated by, 298. Grove, Mr., copper and zinc plates electrified by, 220; - substances radiating heat of different refrangibilities enumerated by, 257;
- the transmission of voltaic electricity investigated by, 298;
- electric heat tested by, 301, 302;
- remarks of, on carbon, 302, 303;
- on the voltaic arc, 304, 305;
- remarks of, on light and heat, 319;
- electric apparatus improved by, 328;
- his definition of the ethereal medium, 355.
Grylli, supposed delicate sense of hearing in, 132. Guanaxato, temperature of the silver-mine of, 228. Gulfs separating stars, 390. Gum-guaiacum, chemically affected by rays of the solar spectrum, 203; - condition of its sensibility to light, 206;
- effect of red rays on, 209;
- used in experiments on parathermic rays, 217, 218.
Gum-lac, electrical intensity measured by means of, 286, 287. Gymnotus electricus, the, 310. Haidinger, M., experiments of, proving water an essential part of crystals, 107. 408; nebulÆ discovered by, 409; annular nebula described, 410; magnitude of planetary nebulÆ computed, 412; globular nebulous cluster described, 413; law of gravitation ascribed to nebulÆ, 416; nebula round ? Argus described, 418; his work on NebulÆ, 419. Herschel, Miss, Encke’s comet seen by, 365; - catalogue of nebulÆ, 407.
Hevelius, divergent flames of a comet described by, 364; - contraction in diameter of comets observed, 377;
- phases in comets observed, 380.
Hieroglyphics interpreted by astronomy, 89. Himalaya, the, inappreciable effect of, on the globe’s surface, 6; - singular effect of refraction on, 156;
- cause of greater elevation of the snow-line on the northern side of, 241;
- flora of, 250.
Hind, Mr., comet’s orbit computed by, 370, 371; - observations of, on Donati’s comet, 379;
- variable stars discovered by, 391;
- vanishing star discovered, 393;
- his belief in planetary systems, 394.
Hindostan, the tidal wave striking on its coasts, 94. Hipparchus, precession discovered by, change of seasons since his age, 80; - phenomenon suggesting his catalogue of the stars, 392.
History corroborated and corrected by astronomy, 87, 89. Hoar-frost, cause of, 269. Holtzmann, M., opinion of, with regard to the vibrations of polarized light, 223. Hoogly, the, bore of, 94. Horizon, effects produced by the denser stratum of air in, 157, 158. Horologium, nebulous patches in, 417. Horton coal-mine, experiments with the pendulum in, 57. Hours, cause of their mal-correspondence over the globe, 86. Hudson’s Bay, tide in, 98. Humboldt, his sufferings from rarity of the atmosphere, 118; - his explanation of the apparent greater acuteness of hearing observed at night, 135;
- observations of, in mines, 228;
- causes of disturbance in the equal diffusion of heat enumerated by, 240;
- identical productions of the Old and New World found by, 251;
- his distribution of palms and grasses, 252;
- green plants found growing in mines by, 253.
Hunt, Mr., coloured image of the solar spectrum obtained by, 209; - image obtained in England, 213;
- his experiments in tracing images by juxtaposition of bodies, 220, 221;
- experiments on the condensing power of rays, 223.
Hurricanes, origin and cause of, 125, 126; - curve described by the axis of, ib.<
Page_342" class="pginternal">342;
- extensive courses of, 344;
- a connected system, 345;
- diamagnetic, 348.
Lion, the, conjunction of planets in, 42. Liquids, balance of forces constituting, 104, 105; - action of capillary attraction on, 113-116.
—— possessing the property of circular polarization of light, 190, 191-193. Liquids, conditions affecting the transmission of radiant heat by, 263; - evaporation from, 269;
- expansion of, by heat, 271;
- propagation of heat in, 273;
- action of heat as a mechanical force on, 275-277.
London, retarding of the tidal wave between Aberdeen and, 94. ——, pendulum vibrating in its latitude, a standard of measurement, 89; - fulgorites exhibited in, 293.
Long, Dr., his attempt to measure distances of fixed stars, 388. Longitude, mode of reckoning mean and true, 9; - of the perihelion and of the epoch defined, 10;
- cause of periodical perturbations in, 14;
- calculation from the moon’s influence on the sun’s, 55;
- data of, used in computing a planet’s place in the heavens, 58-60;
- change effected by precession and nutation in, 81.
Lloyd, experiments of, in polarization of heat, 264. Lubbock, Sir John, theory of planetary motion completed by, 64; - his theory of shooting stars, 423.
LumiÈre cendrÉ, definition of, 227. Lunar distance, defined, 43. —— theory, mean distances obtained from, 43. —— tides of the terrestrial atmosphere, 121. Lundahles, M., motions of heavenly bodies investigated by, 405. Lupus, position of, 390. Lussac, Gay, M., uniting of gases by volumes discovered by, 111; - ascent of, in a balloon, 118;
- course of a lightning flash ascertained by, 292.
Lutetia, diameter of, 56. Lyell, Sir Charles, his theory of changes of temperature in the northern hemisphere, 75; - annual number of volcanic eruptions computed by, 233;
- volcanic phenomena related by, 234.
Lyncis 12, a triple star, 395. Lyra, a variable star in, 391; - a double star, 395;
- nebula, 410.
Machinery, relations of, to force, 353. Mackintosh, Sir James, quotation from, illustrating the essential advantages of study, 1. Maclear, Mr., parallax calculated by, 387. Madeira, vegetation of, 252. Madras, Saturn’s ring discovered from, 66. Magellanic clouds, the, 417, 418. Magnecrystallic action, <
html@files@52869@52869-h@52869-h-37.htm.html#Page_381" class="pginternal">381; velocity of, 400. ——, propagation of heat in, 273; - rotating by electricity, 314.
Meridian, constant, of high water, 92. ——, mode of determining the magnetic, 343. Meridians, size and form of the earth determined from, 46; - measurement of arcs, 47;
- anomalies from local attraction, 48;
- result of the computations, 48, 49;
- permanent, of the moon, 69, 70.
——, magnetic, influencing the direction of metallic veins, 346. Messier, comet of 1770 observed by, 361; - Encke’s comet seen by, 365;
- nebula described by, 409.
Metallic salts, action of the rays of the solar spectrum on, 203. —— springs used in construction of musical instruments, 143; - rods giving musical notes, 144.
Metallic surfaces, polarized light reflected from, 193; - plates, impressions on, from bodies in contact with, 220.
Metals, expansion of, by heat, 271; - propagation of heat in, 274;
- transmission of electricity by, 284;
- electricity developed by oxidation of, 298;
- determining the appearance of a spectrum of voltaic flame, 303;
- distilled in the voltaic arc, 304, 305;
- electro-plating of, 309;
- properties of, modifying electric susceptibility, 333;
- magnetism an agent in the formation of, 346.
Meteor, the bursting of a, 118. Meteors, 420; Meteoric stones, proofs of their foreign origin, 420, 421; MÈtre, adopted by the French as their unit of linear measure, 89. Mica, polarization by induction effected with, 286. Milky Way, the, described, 385; - Sir John Herschel’s description, 385, 386;
- “Coal Sacks,” 386;
- stars composing, 286, 287;
- zone of stars crossing, 390;
- position of variable stars with regard to, 395;
- crowding in, apparent only, 405;
- orbit in the plane of, 406;
- relation of, to the stellar universe, 407;
- nebula resembling, 409;
- its quarter of the heavens, 414, 415;
- dividing the nebulous system, 416, 298;
- spectrum from, 303;
- separated from water by electricity, 307;
- paramagnetic, 344.
Ozone, produced by electricity, 284. Pacific Ocean, mean depth of, 77; - course of tidal waves down, 93;
- mean depth of, 96;
- currents, 100.
Paderborn, fulgorites from, 293. Pallas, inclination of its orbit to the ecliptic, 10; - diameter of, 21;
- astronomical tables, 63;
- ellipticity of its orbit compared with the terrestrial, 74;
- height of its atmosphere, 226;
- comet revolving between the orbits of Mercury and, 367.
Pan’s pipes, vibrations in the air passing over, 142. Parabolic motion, ratio of forces procuring, 382. Parallax of the sun, circumstance favourable to its correction, 21. —— of an object defined, 43. ——, definition, mode of ascertaining, 52; - distances computed from, 52-54;
- calculation from the moon’s horizontal, 55.
—— of fixed stars, 387-390. —— of meteors, 421, 422. Paramagnetic substances, 335, 336. Paramagnetism defined, 335; - substances it is resident in, 336;
- modes of imparting, ib.;
- a dual power, ib.;
- imparted by induction, 337;
- law of its intensity, 338;
- a property of oxygen, 344;
- in antithesis to diamagnetism, 347;
- neutral substances obtained by combinations of diamagnetism and, ib.;
- Dr. Tyndall’s experiments on polarity of, 348;
- dependent on arrangement of molecules, 350, 351;
- affected by compression, 351;
- truth establishing its identity with diamagnetism, 356, 357.
Parathermic rays, analyzed by Sir John Herschel, 217-219. Paris, variation in length of the pendulum at, 51; - mean annual temperature, 228;
- temperature of an Artesian well in, 230.
Paths of comets, 359, 360; - secrets disclosed by their excentricities, 365.
Parry, Sir Edward, turned back by the Polar current, 101; - mean temperature calculated from observations of, 245;
- thermometer at Melville Island marked by, 247.
Pauxis, the Straits of, ebb and flow of the sea in, 98. Peel, Sir William, thunderstorm experienced by, 293, 294. Pegasus, nebulous region of, 417. Pendulum, the, principle equalizing its oscillations, 341; of diamagnetic substances, 347, 348. Polarization of light, definition of, 179; - refracted by various substances, 180-183;
- by reflection, 184;
- angles of, 185;
- phenomena exhibited by transmission through analyzing media, 186-188;
- circular, 189-191;
- theory of circular and elliptical, 192, 193;
- substances producing, 193, 194;
- theory of coloured images formed by, 194;
- accidental, 195;
- discovery of, ib.;
- degraded light incapable of, 198;
- communicating electricity, 220;
- plane of motion of vibrations in, 223.
Polarization of heat, first attempts, 264; —— of electricity by induction, 286. ——, experiment showing the action of magnetism on, 319; - affected by mechanical compression, 352.
Poldice mine, the, temperature of the water pumped from, 229. Poles, the, cause of the flattening of a spheroidal mass at, 6; - diameter of Jupiter at, 27;
- experiment determining the increase of gravitation towards, 49, 50;
- the, drifting of ice from, 100, 101;
- of maximum cold, centres of the isothermal lines, 245, 246;
- nature of magnetic force distinguished by, 332;
- four terrestrial, of maximum magnetic force, two magnetic, 343.
Pollux, an optically double star, 401. Port Bowen Harbour, transmission of sound across, when frozen, 136. Positive electricity, defined, 282; —— impressions in photography, 204. Pouillet, M., his estimate of the mean temperature of space, 119; - quantity of solar heat received by the earth computed by, 238;
- data furnished by, to Professor Thomson, 279;
- development of electricity investigated by, 291.
Powell, Baden, substances producing elliptical polarization enumerated by, 193; - dispersion of light accounted for by the undulatory theory, 200, 201;
- experiments in transmission of radiant heat, 262;
- attempts to polarise heat, 264.
Power, Mr., undulations producing fluorescent light computed by, 197; - law of solar rays acting on media, 198.
PrÆsepe, the, in Cancer, 415. Precession, a, in the equinoxes of planets, its cause, 66; - mean, of the equinoctial points, defined and calculated, 80;
- influence of, on the pole of the equator, on longitudes, 120.
- Sidereal times, mean, periods of, 16;
- resistance offered by, to the power of disturbing forces, 20;
- periods of conjunctions of Jupiter, Saturn, and, 25;
- influence of, on lunar motions, 34, 35;
- action of the planets reflected by, 37;
- eclipses of, 40, 41;
- supposed constitution of, 41;
- his atmosphere, 42;
- mode of finding his parallax, 52, 53;
- mean distance from the earth, 53;
- mass of, 55;
- diameter, 56;
- comparative density, attractive force, 56, 57;
- astronomical tables of, 63;
- deductions from his rotation about an axis, period of, 65;
- attraction of, producing a precession of the equinoxes, 79, 81;
- returns of, a measure of time, 83-85;
- divisions of time, dependent on revolutions of the major axis of his orbit, 86, 87;
- action on tides, 92, 97;
- disturbing the equilibrium of the atmosphere, 121;
- dry and rainy seasons regulated by, 123;
- cause of decreased light and heat in horizontal rays, 157, 158;
- distance of, falsely estimated, 158;
- light polarized by, 195;
- indications of an absorptive atmosphere surrounding, 212, 213;
- his diameter, 224;
- appearance of, through his 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 variations 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;
- increased 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;
- proportion of his light to the moon’s, 404;
- rate and orbit of motion with his system, 405, 406;
- a nebulous star, 412;
- meteoric nebula revolving round, 422;
- gravitating force of, 424, 425.
Sunbeams, resolved into their component colours, 159-162; - law prevailing in the phenomena of, 198;
- light a distinct property of, 214;
- resolved into three spectra, <
ass="pginternal">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 medium for sound, 135;
- light polarized circularly by, 194;
- experiment deciding the velocity of light in, 202;
- law of expansion of, 271;
- process of congelation, 276;
- boiling points of, 277;
- decomposed by electric agency, 307;
- as an electric conductor, 309;
- rotating by electricity, 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, producing 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 instruments invented by, 143;
- paper on musical vibrations read by, 145;
- experiments on sounding boards of, 150;
- experiments on sound reinforced by resonance, 151;
- instrument measuring velocities of electricity and light invented by, 202;
- spectrum of an electric spark observed, 289;
- speed of electricity measured, 289, 290;
- experiments on the spectrum of Voltaic flame, 303.
- Willis, Mr., articulating machine invented 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;
- phenomena of rotatory motion, 125;
- hurricanes, 125, 128;
- agency of, influencing temperature, 244, 245.
- Wines, range of cultivation of the best, 250.
- Winter, atmospheric electricity in, Plate 1.
These correspond to No. 1, 6, and 7 of Faraday’s plate in his 29th Series of Experimental Researches in Electricity. Plate 10. Fig. 1. Spiral nebulÆ of 51 Messier, as seen by Lord Rosse. Fig. 2. Great nebula of Orion.
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