INDEX.
- Aberdeen, high water at, 94.
- Absorption, influence of, on temperature, 239;
- difference of sea and land in power of, 242;
- gradually decreasing, in transmission of radiant heat, 259;
- of radiant heat, varying with substances, 268;
- a transfer of force, 275, 276.
- Acceleration of the moon’s mean motion, 37, 38.
- Adams, Mr., perturbation in Uranus’s motion computed by, 22;
- discovery of Neptune, 62.
- Aërolites, theory of, 420, 423.
- Africa, tidal wave passing, 94;
- mean annual equatorial temperature in, 245;
- indigenous productions of, 249, 250.
- Air, comparative velocity of light in water and, 202.
- Airy, Professor, periodic inequality in the solar system worked out by, 26;
- phenomenon observed by, during an eclipse, 41;
- mass of Jupiter ascertained by, 55;
- experiments ascertaining its density, 57;
- astronomical tables improved by, 63;
- discoveries in polarization of light, 192, 193.
- Aldebaran, an optically double star, 401.
- Aleutian Islands, the, vegetation of, 252.
- Alexandria, arc of the meridian measured between Syene and, 49.
- Algæ, districts of distinct species of, 252;
- banks of, in the Atlantic, 253.
- Algol, fluctuations in lustre of, 390, 391.
- Alhazen, effects of refraction observed by, 155.
- Alkalies, resolved into metallic oxides, 307.
- Alpha Antaris, “Coal Sacks” between α Centauri and, 386.
- Alpha Aquilæ, an optically double star, 401.
- —— Centauri, the parallax of, 54;
- its rank, 384;
- the Milky Way near, 386;
- parallax, as determined by Henderson and Maclear, 387;
- distance from the sun, 388;
- orbit and mass of, 399, 400;
- colour, 401;
- amount of light emitted by, 404;
- rate of its proper motion, 404, 405;
- globular nebulous cluster, 414.
- —— Crucis, zone of stars passing through, 385;
- zone between η Argûs and, 390;
- nebulous cluster round, 415.
- —— Lyræ, the polar star of the northern hemisphere, 82;
- parallax of, 388;
- distance from the sun, 389;
- an optically double star, 400;
- amount of light emitted by, 404.
- —— Orionis, a variable star, 393, 394.
- Alum, experiments on the crystallization of, 106, 107;
- heat transmitted through, 261, 262.
- Amazons, the river of, distance from its mouth where tides are perceptible, 98;
- area occupied by forests on, 243.
- America, course of the tidal wave along its coasts, 93, 94;
- mean annual equatorial temperature in, 245;
- separation of isothermal lines in high latitudes, ib.;
- number of known species of plants indigenous in, 249;
- number of species of trees, 252;
- shooting stars over the continent of, 421.
- ——, South, area of country raised by an earthquake in, 234.
- Ampère, M., his discovery in electricity, 316;
- theory of magnetism, 317, 318;
- experiment testing his theory, 319, 320.
- Analysis, boundless dominion of, 427, 428.
- Andes, the, proportion of, to the earth’s mass, 6;
- increasing rarity of the air experienced in ascending, 118.
- Andromeda, nebula in, 413;
- Angström, the electric spark defined by, 303.
- Animals, specific diversity of, laws regulating their distribution, 254, 255.
- Annual equation, the, of the moon, 35, 36.
- —— variations in mean values of the magnetic elements, 343.
- Annular nebulæ, 409;
- in the northern hemisphere, 410, 411.
- Antarctic Ocean, tidal wave rising in 93;
- period of its passage to the Thames, 94;
- depth of the stratum of constant temperature in, 101;
- depression of the barometer observed in, 120.
- Antilles Islands, hurricanes beginning at, 126.
- Antinori, Cav., experiments of, in electricity, 333.
- Antinous, comet observed in the constellation of, 372;
- the Milky Way between Orion and, 386.
- Antithesis, the general character of magnetism, 339.
- Aphelion of a planet’s path defined, 16.
- Apogee, solar, its coincidence with the solstices, 86, 87.
- April, 1833, disappearance of Saturn’s rings, 67;
- apparent and mean time coinciding in, 84.
- Apsides of an axis defined, 9;
- direct, variable motion of, 14;
- cause of their advance, or recession, 16.
- Apures, the mission of the, Humboldt’s observations on sound at, 135.
- Aqueous vapour, proportion of, in the atmosphere, 117.
- Ara, nebula in, 414.
- Arabian Gulf, the, monsoons blowing over, 124.
- Arabs, the, their observations on planetary irregularities, 26;
- lunar eclipses observed by, 38;
- their division of time, 85;
- the pendulum used as a measure of time by, 90.
- Arago, François, experiment by, in proof of the undulatory theory of light, 200;
- decisive experiment suggested by, 202;
- observations in photography, 213;
- observations on the moon’s atmosphere, 226;
- increase of temperature below the earth’s surface calculated by, 230;
- slow communication of temperature from the earth, observed, 244;
- source of magnetism discovered, 330;
- theory of his magnetic experiments, 332;
- divergent flames of a comet described by, 364;
- his treatise on comets, 368;
- nature of comet’s light determined by, 380, 381;
- numbers of comets computed, 381, 382;
- remark of, on fixed stars, 405.
- Arc, the Voltaic, 303-305.
- Arcet, M. d’, vibration of fibres of the retina according to, 178.
- Archer, Scott, stimulus given to photography by, 207.
- Arcs of the meridian, mode of measuring, 47.
- Arctic Sea, depth of the zone of constant temperature, 101.
- —— regions, vegetation found in, 249.
- Arcturus, comet bearing comparison with, 379;
- Areas, described by the radii vectores of planets, a test of disturbing forces, 10;
- unequable description of, 15.
- Argelander, M., period of a comet calculated by, 370;
- his mode of estimating distance of fixed stars, 389;
- periods of fluctuation in stars computed by, 390, 391;
- sun’s motion proved, 405.
- Argentine preparations in photography, chemical energy varying with, 207, 208;
- changes effected by washing with alkalies, 210, 211.
- Argo, variable star in, 393.
- Aries, season of the sun’s entrance into, in Hipparchus’ age, 80.
- Arseniate of soda, its crystals, 109.
- Artesian wells, mode of sinking, origin of the name, 230.
- Asia, indigenous productions of, 249.
- Assyrians, the, division of time by, 85.
- Astronomers, fruits of their labours, 3;
- question still to be resolved by, 24;
- terrestrial orbit differently measured by, 36.
- Astronomical distances, method of measuring, 43;
- tables, method of forming, 58-64.
- Astronomy, its rank in the physical sciences, an important office of, 1;
- studies necessary to the study of, 2;
- the key to divers problems in physical science, 3;
- the two greatest discoveries in, 23;
- the three departments of, 58;
- standards for measurement afforded by, 83;
- application of, to chronology, 87-89;
- furnishing standards of weights and measures, 89, 90;
- atmospheric effects connecting the laws of molecular attraction with, 102;
- progress lately made by, 419, 420.
- Atalanta, diameter of, 56.
- Atlantic Ocean, direction of tidal waves in, 93;
- conditions modifying tides, 94;
- depth of, 96;
- currents, 100;
- origin of hurricanes, 126;
- superficial temperature of, 244;
- distinct vegetation of the polar basin, 252;
- beds of algæ in, 253;
- meteors falling in, 421.
- —— telegraph, 325, 326;
- terrestrial magnetism disturbing, 346.
- Atmosphere of nebulous stars, 411, 412.
- —— of planets, 226, 227.
- —— of the sun, its constitution, 42;
- indications of an absorptive surrounding the luminous, 213;
- 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, 283;
- destruction of, producing electricity, 284;
- laws of electrical, 286-288;
- modes of, in static and in voltaic electricity, 317;
- action of planetary, on comet’s orbits, 361-363;
- range of solar, 365.
- Aurora, the, affecting the compass, 312.
- Australia, evidence of deserts in the interior of, 124;
- species of plants common to Europe and, 251.
- Auvergne, temperature of hot springs in, 231.
- Axes, change in form of masses revolving round, 6.
- ——, major, length of, in orbits, invariable, 20;
- of the orbits of Jupiter’s satellites, cause of the direct motion observed in, 28;
- position of, in the solar system, 65;
- a nutation in planetary, 66;
- of the moon, 68, 69;
- mechanical law affecting, 76.
- ——, optic, of crystals, 183.
- Axis, greater, of the earth’s orbit, period of its revolution, 38;
- period of the earth’s revolution, 58;
- excess of Jupiter’s equatorial over his polar, 66;
- of rotation, proof of its being invariable, 76, 77.
- ——, major, of a planet’s orbit, distance from the sun measured by, 8;
- designation of its extremities, 9;
- length of, determining the form of the orbit, 10;
- periods of its revolutions, 17;
- length of, not permanently changed, 20;
- Jupiter’s periodically diminished, Saturn’s increased, 26;
- of the solar ellipse, period of its revolution, 86.
- ——, magnecrystallic, 349.
- Azores, the, icebergs reaching, 100.
- Babbage, Charles, his theory of volcanic action, 235-237;
- quotation from, on the nature of force, 353.
- Babinet, M., his theory of dark lines observed in the solar spectrum, 163;
- comet’s light computed by, 359.
- Babylon, eclipse observed at, 36.
- Bacon, Francis, anticipation of discovery by, 32.
- Baily, Mr., compression of the terrestrial spheroid calculated by, 50;
- density of the earth determined, 57;
- fictitious antiquity ascribed to Indian astronomical observations, 88.
- Bali, volcanic eruption in, 233.
- Balloon, rarity of the air felt in a, 118;
- observations made from, 119.
- Baltic, the, a tideless sea, 98;
- decreased atmospheric pressure on the shores of, 120.
- Barlow, Mr., observations supporting his theory of electric currents, 346.
- Barometer, the, principles of cohesion and attraction applied to the construction of, 113;
- density of the atmosphere measured by, 117;
- mean heights of, varying with atmospheric densities, 118;
- mountain heights measured by, 119, 120;
- atmospheric phenomena affecting, 120;
- used to trace the course of atmospheric waves, 121;
- cause of sudden fall in, before hurricanes, 127;
- refraction varying with, 154.
- Barrow, Cape, observations on magnetic storms at, 345, 346.
- Battery, voltaic, construction of, 298, 299;
- Professor Daniell’s improvements, 299, 300;
- action of, charged with water, 300;
- constant flow of electricity obtained by means of, 312.
- ——, magnetic, constructed by Dr. Faraday, 324, 325;
- Mr. Henley’s magneto-electric, 325;
- Atlantic telegraph, 326;
- structure of, for land telegraphs, 328;
- relation of heat to power of, 329;
- thermo-electric, 333.
- Batsha, port of, tides neutralised in, 99.
- Bayle, comparative density of the atmosphere in interplanetary space according to his law, 356.
- Bear, Little, the, the polar star in, 82.
- Becquerel, M. E., unexplained photographic phenomenon observed by, 213;
- phosphorescent property in the solar spectrum discovered, 216;
- cause of phosphorescence, 217;
- electricity excited by pressure, 283;
- light attributed to electricity by, 284;
- cause of phosphorescence investigated, 296;
- instrument comparing intensities of electricities invented, 300;
- crystals formed by agency of electricity, 308;
- thermo-electric battery constructed by, 333;
- effect of atmospheric on terrestrial magnetism estimated, 345.
- Beehive, the, a nebulous star, 415.
- Berard, M., experiments of, in polarizing heat, 264.
- Berlin, line of coincidence in temperature passing through, 238.
- Berne, increasing temperature of a deserted mine in, 230.
- Berre, Dr., photographic pictures perfected by, 205.
- Bessel, M., his calculations from measurements of arcs of the meridian, 48;
- calculation of the sun’s mean apparent diameter, 56;
- his computation of the mass of Saturn’s ring, 68;
- diminished obliquity of the ecliptic observed by, 81;
- parallax calculated, 389;
- his theory of Sirius’s irregular motions, 392;
- catalogue of double stars, 396;
- mass of 61 Cygni found by, 404.
- Beta Lyræ, a variable star, 391;
- nebula between γ Lyræ and, 410.
- Benzenberg, M., velocities of falling stars computed by, 423.
- Biela, M., date of the discovery of his comet, 367;
- possibility of collision with the earth, 368;
- present and prospective planetary influence on, 369;
- becoming two distinct bodies, 369, 370.
- Binary systems of stars, 395-406.
- Biot, M., his ascent in a balloon, 118;
- experiments of, on the transmission of sounds through pipes, 137;
- liquids possessing the power of circular polarization discovered by, 190;
- his theory of circular polarization, 191;
- cause of phosphorescence in the solar spectrum investigated by, 217.
- Birds, distribution of distinct species of, 255.
- Birt, Mr., atmospheric waves measured by, 121, 122.
- Bise, in Switzerland, cause of, 242.
- Bismuth, its magnetic and electric properties, 347.
- Black Sea, the, scarcely affected by tides, 98.
- Bode, Baron, law of, assumed in computing Neptune’s position, 61;
- failing in the case of Neptune, 63.
- Bond, Mr., satellite of Saturn discovered by, 32;
- elliptical nebula resolved, 413.
- Bonnycastle, Captain, phosphorescent phenomenon observed by, 295, 296.
- Bonpland, M., identical productions of the Old and New World found by, 251.
- Boötes, nebulous system in, 417.
- Bore, the, of the Hoogly, its origin, 94.
- Botanical districts, distinct, of the globe, 251, 252.
- Botto, M., thermo-electricity used in decomposition by, 333.
- Bouguer, degrees of the meridian measured by, 48.
- Boussingault, M., depth of the underground stratum of constant heat calculated by, 228.
- Bouvard, M., atmospheric undulations estimated by, 121.
- Bradley, Dr., motion of the pole of the equator discovered by, 84;
- his tables of refraction, 155.
- Brahmins, measurement of time by, 85.
- Brand, M., observation of, on meteors, 423.
- Brewster, Sir David, his analysis of the solar spectrum, 161;
- experiments on rayless lines, 163;
- experiments on spectra of flames, 164;
- law discovered by, determining angles of polarization for light, 183;
- experiments on fluorescence of light, 197;
- line of coincidence in temperature of springs and of the atmosphere determined by, 238;
- temperature of a pole of maximum cold determined, 245;
- isogeothermal lines determined by, 246;
- observations on the light of fixed stars, 402.
- Brighton, phenomenon caused by reflection observed from, 157.
- Brinkley, Bishop, mass of the moon determined by, 56.
- British Channel, height of tides in, 98.
- —— Isles, atmospheric wave passing over, 121.
- Brorsen, M., periods of comets discovered by, 370.
- Brown, Dr. Robert, peculiar vegetation found by, in Australia, 251.
- Buchan, Dr., phenomenon caused by reflection observed by, 157.
- Cæsar, Julius, era computed from his reign, 85.
- Cagniard de la Tour, M., instrument designed by, measuring musical notes, 143.
- Calms produced by the trade-winds, 122, 123.
- Calorific rays.
- Calotype, the invention of, 204.
- Camelopard, nebulous system in, 417.
- Canaries, the, vegetation of, 252.
- Canary-glass, fluorescence of light in, 196.
- Cancer, the calms of, 123;
- the tropic of, marking the limit of the trade-winds, 126;
- nebulous cluster in, 415.
- Canis Major, position of, 390.
- —— Venatica, nebulous system in, 417.
- Capillarity, theory of, 113;
- forces producing, 114;
- familiar examples of, 115;
- curious phenomena, 115, 116.
- Capricorn, the calms of, 123;
- the tropic of, hurricanes changing their direction at, 126.
- Carbon, its powers contrasted as a crystal and as an opaque amorphous substance, 302, 303.
- Carbonate of lime.
- Carbonic oxide, its constituent parts, 111.
- —— acid, proportion of, in the atmosphere, 117.
- Cardinal points, the, position of continental masses with regard to, influencing temperature, 244.
- Caribbean Islands, hurricanes beginning at, 126.
- Castor, discovered by Sir William Herschel, 396.
- Cassiopeia, star appearing and vanishing in, 392, 393.
- Categat, the, consequence of its narrowness, 98.
- Cauchy, M., data furnished by, for investigation of the theory of light, 201.
- Cayenne, variation in length of the pendulum between Paris and, 51.
- Celestial bodies:
- law of their mutual attraction, 4;
- of the solar system:
- law determining their attraction to the sun, 5;
- problem to fix the positions of, on occurrence of disturbance in their motions through counteracting attractions, 11;
- theory of their mutual connection and dependence, 24;
- mode of finding the absolute distances of, 43;
- distances of, computed from their parallax, 52, 54;
- apparent position of, affected by refraction, 153, 154;
- apparent infinity of, 420.
- Centaur, position of, 390;
- brilliant double star in, 399.
- Central Asia, the mountains of, their ascent by Marco Polo, 118.
- Centre of gravity.
- Centrifugal force, moon’s motions modified by, 5;
- influence of, on planet-forms, 6;
- retarding oscillations of the pendulum, 32;
- action of, in determining the figure of the earth, 44, 45;
- measurement of its intensity, 49;
- resolved into two forces, its action on the sea, 100.
- Ceres, astronomical tables of, 63;
- height of her atmosphere, 226;
- comet of 1770 revolving beyond the orbit of, 361.
- Cetus, nebulous patches crossing, 417.
- Chaldeans, the, mean longitude found from observations of, 36;
- result of comparison of their observations with modern, 38.
- Challis, Professor, Brewster’s analysis of light questioned by, 161.
- Charcoal, light produced by electricity from, 302-303.
- Charles V., the Emperor, observations on comets, made in his reign, 370.
- Chaudes Aigues, temperature of, 231.
- Chemical action of rays of the solar spectrum, 203, 207;
- varying maximum of energy, 208;
- action varying with refrangibility, 209-212;
- action in luminous spectrum not continuous, 213;
- energy an independent property of rays, 214;
- properties of the parathermic rays, 219;
- action of light maintaining vegetation, 249;
- affinities the source of the power of steam, 278;
- of electricity on oxygen, 284;
- eliciting voltaic electricity, 297, 300;
- voltaic electricity, an agent in, analysis, 307, 308.
- —— combinations, theory of, 110;
- invariable proportions of, 111;
- cohesive force inducing, 112;
- producing combustion, 270.
- —— force, the power of, 112.
- —— rays, causing the deposition of dew, 269.
- Chile, elevation of land by an earthquake in, 234.
- China, distinct flora of, 251.
- —— Sea, the, monsoons blowing over, 124.
- —— ink, polarized light reflected from, 193.
- Chinese, the, observations of, on the mean motions of Jupiter and Saturn, 25;
- proof of their early study of astronomy, 88;
- decimal divisions used by, 90;
- elements of comets computed from their observation, 365;
- comet of 1264 recorded by, 370.
- —— Tartary, herbarium collected in, 250, 251.
- Chladni, discovery of, in musical science, 145.
- Christian era, traces of astronomical records before, 365.
- Chromatype, the invention of, 206.
- Chronology, dependent on astronomy, 87-89.
- Chrysotype, the, coloured photographs obtained from, 206.
- Circuit, galvanic, modes of obtaining, 332.
- Circular arcs, principle with regard to their sines and cosines, a pledge for the stability of the solar system, 20.
- —— motion, ratio of forces procuring, 382.
- —— orbits of planets distinguished from elliptical, 8;
- —— polarization of light, 189-192;
- Circumference of the earth, 49.
- Civil time, measure of its periods, 83;
- not precisely adjusted to solar revolutions, 85.
- Clairaut, periodic time of Halley’s comet computed by, 362, 363.
- Cleavages of crystals, 109;
- position of, affecting the intensity of magnetic action, 350.
- Climates, planetary, 225, 226;
- cause of the different terrestrial, 237;
- phenomena affecting, 239, 240;
- causes of variety of, 243, 244;
- milder, of the Polar Ocean, 245, 246;
- like mean annual temperatures not ensuring like, 246;
- compensations of irregularities, 247.
- Clocks, showing apparent sidereal time, 83;
- regulated to show decimal time, 84;
- irregular action of, corrected by the laws of unequal expansion, 272.
- Clouds, circling the belt of equatorial calms, 123;
- region of, 124;
- electricity evolved from, 291-292.
- Cloyne, Bishop of, his calculation of the moon’s mass, 56.
- Coal-measures, tropical plants in, 72, 73;
- age of their formation, 75.
- Coal, chemical force evolved from, by combustion, 278;
- source of its combustible qualities, 279, 280.
- “Coal Sacks” in the Milky Way, 386.
- Cohesion, influence of, on matter, 105;
- phenomena arising from its force, 106;
- attraction of, overcome by the expansive power of heat, 271.
- Cohesive force, properties of material molecules constituting, 103;
- effectual only to unite particles of like nature, 110;
- inducing chemical combination, 112;
- capillary attraction, an action of, 113.
- Coins, impressions taken from, by contact, 220;
- Cold, contraction caused by, 271, 272;
- mitigated by slow propagation of heat in air, 273;
- generated by voltaic electricity, 302;
- increasing the conducting power of the air, 345.
- Colladon, M., experiments of, testing the velocity of sound, 135.
- Collision between the earth and comets, possibilities, possible effects of, 367, 369.
- Collodion, sensitiveness of, to light, 203;
- properties of, as an agent in photography, 207.
- Colours, seven primary, 159;
- theory of the decomposition of white light into, 160;
- degree of refrangibility not invariable, 161;
- three primary, ib.;
- new, discovered by Sir John Herschel, 162;
- rays refracted without, 164;
- rarely homogeneous, 165;
- experiments on accidental and complementary, 165, 166;
- determined by undulations of ether, experiments, 170-175;
- of material substances, whence derived, 175;
- produced by analyzing polarized light, 186-188;
- varying with refrangibility of rays, 198;
- obtained in photography, 206;
- images of the solar spectrum imitating the prismatic, 208-209;
- of seaweeds, 253;
- not invariably dependent on light, ib.;
- affected by absorption and reflection, 268;
- of the electric spark, affected by the atmosphere, 289;
- of the voltaic spectrum, 303;
- of the electric spark, 304;
- produced by oxidation on silver, 305;
- of the fixed stars, 401, 402;
- of planetary nebulæ, 412;
- of nebulous clusters, 415.
- Columbus, beds of algæ found by, 253.
- Column, capillary, forces producing changes in its form, 114, 115.
- Coma Berenices, a nebulous cluster, 415;
- nebulous zone passing, 416, 417.
- Combustion, cause of, 270;
- Comets, attraction by the sun of, 5;
- disturbances in the motion of, a key to the nature of the ethereal medium, 22;
- retrograde motion in, 33;
- passing through Jupiter’s satellites, 69;
- return of, to their perihelia, furnishing historical data, 88;
- existence of the luminous ether demonstrated by, 168, 169;
- terrestrial atmosphere unaffected by, 358;
- amount of their light computed, 358, 359;
- passages of, through the solar system, 359;
- velocity, paths of, 359, 360;
- proof of the return of, 360;
- disturbing action of planets on their orbits, 361;
- of 1770, an example, 361, 362;
- computed return of Halley’s, 362, 363;
- aspects, records of Halley’s, 363-365;
- discoveries made by the revolutions of, 365;
- of the solar system, Encke’s, 365, 366;
- Biela’s, possibility of collision with, 367, 370;
- periods of various, 370;
- cause of their brilliancy, 371;
- velocity, sun’s influence on, 371, 372;
- of 1843, 372, 373;
- their constitution, 373, 374;
- of 1811, its luminous envelopes, 374, 375;
- sudden convulsions in, 375;
- tails, 375-377;
- causes assigned for contraction of diameter in, 377, 378;
- Donati’s, 378, 379;
- nature of their light, 379-381;
- computations of their numbers, 381, 382;
- orbits of, 383;
- nebula resembling, 413.
- Compass, mariner’s, phenomena disturbing, 312;
- intensity of a galvanic current measured by, 315.
- Compression of the terrestrial spheroid, calculations of, 48-51;
- cause of the great, in Jupiter, 66;
- measures of, from pressure of superincumbent mass, 78;
- effect of, on magnetic action, 351.
- Concord, a, in music, 142.
- Conductors of electricity, 284, 285;
- lightning, 293;
- molecular structure determining the power of, 303.
- Conic sections, conditions compelling bodies in space to move in, 5;
- principle determining their nature, 11.
- Constellations, nearest the sun, 390;
- where the orbit of the solar system lies, 406;
- occupied by the nebulous system, 417.
- Contraction caused by cold, 271, 272.
- Cook, Captain, object of his first voyage, 53.
- Cooper, Mr., list of missing stars drawn up by, 395.
- Copper, electricity communicated to plates of, 220;
- lightning-conductors of, 293;
- action of an electro-magnet on, 351, 352.
- Cordier, temperature of mines observed by, 228.
- Cordilleras, effect on temperature of their table-lands, 241.
- Corn, a, field used to illustrate the propagation of sound, 129, 130.
- Cornwall, hot-springs in mines of, 229.
- Corona Australis, nebula in, 414.
- Corpuscular theory of light, 167;
- Coseguina, volcanic irruption of, 233.
- Coulomb, instrument measuring electrical intensity, invented by, 287.
- Creation, vastness and magnificence of, 2.
- Crimea, cause of the great storm in the, 122.
- Cross, Mr., voltaic battery with constant action invented by, 300.
- Cross, the Southern, vacant patches of the Milky Way near, 386.
- Crystallization defined, 106;
- forms of, their variety affected by temperature, 107, 108;
- permanent and variable forms, 108, 109;
- cleavages in, 109;
- common to all substances, ib.;
- by the agency of electricity, 308, 309.
- Crystals, conditions determining their forms, 107-109;
- optic axes of, 183;
- used in polarizing light, 186, 188;
- changes in, effected by compression, 189;
- transmission of rays of heat by, 258;
- expansion of, by heat, 272, 273;
- formed by electricity, 308;
- action of magnetism in, 349, 350;
- circumstances determining the set of, 350, 351;
- effect of temperature on magnetized, 352.
- Cumming, Professor, experiments of, in thermo-electricity, 333.
- Currents, two great, setting from each pole towards the equator, 100;
- proving the rotation of winds, 124, 125.
- ——, electric, flow of, regulated by Volta, 297-299;
- characteristics of Voltaic, 301;
- conductors, non-conductors of, 309;
- continuous flow of Voltaic, 312;
- action of, on magnets, 313-315;
- reciprocal and mutual action of magnetic and electric, 316, 317;
- Ampère’s theory of, unsolved difficulties, 317, 318;
- effect of, on polarized rays, 319;
- electric, evolved by magnets, 322, 323;
- their power of producing induction, 324;
- direction of, produced by rotation, 330-332;
- evolved by application of heat, 332, 333;
- produced by intersecting magnetic curves, 339;
- induced by crossing terrestrial lines of magnetic force, 342.
- Curves, described by bodies projected in space, 5.
- ——, magnetic, 338;
- electricity produced by intersecting, 339;
- nature of, proved by Dr. Faraday, 339, 340;
- terrestrial, 341, 342;
- extent of the range of terrestrial, 344;
- complete connected system of the terrestrial, 345;
- inductive effect on the Atlantic telegraph, 346;
- diamagnetic, 348.
- Cyanite, changes effected in, by magnetism, 349.
- Cyanotypes, coloured photographs obtained by, 206.
- Cygni 61, distance from the sun of, 389;
- Cygnus, portion of the Milky Way lying between α Centauri and, 386.
- Cylinders, rotating by electricity, 313;
- Dalcoath copper-mine, its temperature, 228.
- Daguerre, M., his inventions in photography, 205;
- action of light on the iodide of silver explained by, 219.
- Daguerreotype, the, invention of, 205.
- Dalton, Dr., law of definite proportion established by, 111;
- law of the wind’s rotation observed by, 125.
- Damoiseau, M., perturbations of a comet computed by, 367.
- Daniell, Professor, Voltaic battery improved by, 299.
- Daubuisson, M., observations of, in mines, 228.
- Davy, Sir Humphry, his first attempts to produce photographic pictures, 203-204;
- experiment of, proving identity of heat and motion, 275;
- experiments on the electric spectrum, 289;
- alkalies, earths decomposed by, 307.
- Days, law determining the length of, 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, 227.
- Discord, a, in music, 142.
- Diurnal tides of the atmosphere, their duration, 121.
- —— variations in mean values of the magnetic elements, 343.
- Dœbereiner, M., spontaneous combustion discovered by, 112.
- Doldrums, region of the, 123.
- Dollond, Mr., achromatic telescope perfected by, 165.
- Donati, Signore, discovery of his comet, 378;
- changes in, its irregularities, 379.
- Doradus, nebulous patches on, 417.
- Dorpat, occultation of a star observed from, 364.
- Double nebulæ, 411.
- Double stars, catalogues of, 395, 396;
- formulæ obtaining the relative position and motions, 396, 397;
- eclipse in γ Virginis, 397;
- orbit of, determined, 398;
- eclipse in ζ Herculis, ib.;
- orbits and periodic times of, 398, 399;
- anomalies in motions, 400;
- optically double, 400, 401;
- colours of, 401;
- rays composing the light of, 401, 402;
- passage of light from, furnishing data to ascertaining their actual distance, 402, 403;
- data for finding their masses, 403, 404;
- calculations founded on the quantity of light emitted from, 404;
- real and apparent motions of, 404-406;
- apparent periodic time, 406, 407;
- connection of elliptical nebulæ with, 411.
- Dove, Professor, law of the wind’s rotation developed by, 125;
- average temperature of the earth’s surface estimated by, 237.
- Draco, nebulous system in, 417.
- Draper, Professor, experiments of, on fluorescence of light, 198;
- experiments in photography, 213;
- properties of parathermic rays discovered by, 219;
- spectrum produced from diffracted light, 223;
- theory of heat propagated by undulations, 267.
- Dunlop, Mr., revolution of a double star calculated by, 400.
- Dusejour, M., distances of comets computed by, 359.
- Dynamic electricity, 297.
- —— theory of heat, fundamental principle of, 357.
- Dynamic equator of the earth, 343.
- Dynamical theory of heat, 274, 275;
- illustrated by liquefaction and condensation, 278;
- by generation of steam, 276, 277;
- power of nature, 279-281.
- Dynamics, principle in, a law, with regard to the earth’s rotation, 72;
- electro, discovery of action of currents in, 316;
- the theory of, universal application of, 426, 427.
- Earth, the, influence of its form on attraction, 4;
- square of the moon’s distance from, 5;
- form of, 6, 7;
- moon’s influence on its rotations, 7;
- diameter of, 21;
- mean distance from the sun, ib. note;
- permanence of revolution in its times and seasons, 23;
- perturbation in the mean motion of Venus and, 26;
- proof of the motion of, in its orbit, of its rotation, 32;
- variations in its attraction of the moon, 37;
- compression of its spheroid, 38;
- internal structure of, 39;
- its mean distance from the sun, 43;
- theoretical investigation of its figure, 44-46;
- dimensions of, determined, 48, 49;
- figure of, found by calculating its variations in gravitation, 49-51;
- density compared with the sun, 56;
- experiments finding its mean density, 57, 58;
- rate of revolution round its axis, 58;
- its diurnal rotation immutable, 71, 72;
- changes in temperature and their causes, 73, 74;
- nature of the revolutions producing geological changes, 76, 77;
- conjectures touching its internal structure, 78;
- effects produced by solar and lunar attraction affecting its equator, 79-81;
- its form furnishing standards of weight and measure, 89;
- rotation of, acting on tides, 92;
- attraction of, affecting the lunar atmosphere, 226;
- conjectured constitution of its interior, 231, 232;
- principles regulating the diffusion of solar heat, 237-247;
- distribution of known species of plants over, 249-252;
- electric tension of, 291;
- lines of magnetic force issuing from, 341;
- magnetic properties of, 342, 343;
- effect of its collision with a comet, 368;
- nearest approach of comets to, 369;
- passage of light from α Centauri to, 388;
- theories of meteors falling on, 421-423.
- Earthquakes in South America, 234.
- Earths, decomposed by voltaic electricity, 307.
- Eastern coasts, cause of their colder climates, 244.
- Ebb, see Tides.
- Éboulemens of mountains in Switzerland, cause of, 271.
- Echoes, theory of their origin, 137, 138.
- Eclipses, lunar, accelerated revolutions proved by observations of, 36;
- observations of, confirming results of analysis, 38;
- principle regulating their return, 39;
- refraction of rays by the terrestrial atmosphere, 40.
- ——, solar, 40;
- ——, planetary, 42;
- the solar atmosphere visible in, 224;
- of double stars, 397, 398.
- Ecliptic, the, forming the equinoxes, 9;
- latitude reckoned from the plane of, ib.;
- deviations of planetary orbits from, 10;
- forces affecting their position towards, 15;
- their compensated and uncompensated variations to the plane of, 18, 19;
- secular variation in the plane of, 23;
- orbits of satellites, nearly perpendicular to, 33;
- lunar motions towards, 35;
- inclination of the sun’s plane of rotation to, 65;
- inclination of the plane of Saturn’s rings, 67;
- inclination of the plane of the terrestrial equator, 79;
- tendency of its plane to coincide with the equatorial, ib.;
- retrograde motion of the equinoctial points on, 80;
- obliquity of, affecting the duration of time, 84.
- Edinburgh, comparatively equal mean annual temperature of, 246.
- Egypt, hieroglyphic manuscript from, interpreted by astronomy, 89.
- Egyptians, the civil year of, 85.
- Elastic impact, the foundation of dynamical theories, 357.
- Elasticity, property of, resisting compression, 105.
- Electric telegraphs, experiment suggesting the principle of, 323;
- Electricity assumed as the medium attracting particles of matter, 103, 104;
- identical with chemical affinity, 110;
- in composition and decomposition, subject to laws of definite proportion, 112;
- influencing winds, 125;
- its comparative velocity, 138;
- producing phosphorescence, 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 terrestrial orbit, 368;
- prospective and present planetary influence on, 369;
- disappearance of its tail and nucleus, 369;
- referred to, 377;
- contraction of diameter, ib.
- England, arcs of the meridian measured in, 48;
- course of the tidal wave towards its west coast, 94;
- peculiarities of photography in, 213;
- meteors falling in, 421.
- Engravings copied by photography, 204;
- impressions taken by contact with iodized silver, 221;
- impressions taken from, by galvanism, 309.
- Epipolic light, 197.
- Epsilon Orionis, zone of stars passing through, 385.
- Equation of the centre, defined, 9;
- Equator, the, forces compelling the wider circle of, 6;
- inclination of the terrestrial to the plane of the ecliptic, 23;
- of the solar system, 24;
- measure of the centrifugal force at, 49;
- calculation from lunar action on the terrestrial, 55;
- effects produced by external attraction influencing the direction of its plane, 79, 80;
- inequality in its polar motion, 81;
- cause of the calms at, 122;
- depth of the underground stratum of constant temperature at, 228;
- maximum of solar heating influence, 238;
- superficial extent of land, 244;
- mean annual temperature, 245.
- Equator of the sun, maximum of solar heat attained in, 225.
- ——, dynamic, surrounding the terrestrial globe, 343.
- ——, magnetic, of the earth, 343.
- Equinoctial circle, the, defined, 9.
- —— points, effects of solar and lunar attraction on, 79;
- period of their revolution, 80;
- measuring time, 83.
- Equinoxes, the, defined, 9;
- venial, a point whence planetary motions are estimated, ib.;
- of the planets, cause of a precession in, 66;
- causes preventing their invariable correspondence with points of the ecliptic, 79;
- precession affecting the seasons, 80;
- secular motion of, periodic variations, 80, 81;
- eras depending on the precession of, 86, 87;
- tides augmented in, 97.
- Eras, astronomical, determined by the position of the major axis of the solar ellipse, 86, 87.
- Eratosthenes, the earth’s circumference measured by, 49.
- Eridanus, nebulous patches crossing, 417.
- Erman, M., depression of the barometer observed by, 120.
- Eruptions, volcanic, recorded, 234.
- Eta Aquilæ, a variable star, 391.
- —— Argûs, zone stretching from, 390;
- —— Coronæ, periodic time of, 398.
- Etna, measurements of, 120.
- Ethereal medium, undulations of, propagating heat, 267;
- permeable to lines of magnetic force, 344;
- its density, 356;
- transmitting gravity, ib.;
- magnetic, 356, 357;
- offices discharged by, 357;
- pervading the visible creation, 358;
- influence of, on comet motion, 365;
- astral revolutions accelerated by, 366;
- probable increase in density of, 367.
- Europe, atmospheric wave passing over, 121;
- causes of variation of climate in, 244;
- separation of isothermal lines in high latitudes of, 245;
- differences of latitude enjoying the same mean temperature, 246;
- indigenous productions of, 249;
- number of indigenous productions common to Australia and, 251;
- number of species of forest trees, 252.
- Eudoxus, Plato’s contemporary, astronomical observation of, 88.
- Evaporation, conditions affecting, 269, 270.
- Everest, Colonel, arc of the meridian measured by, 48.
- Excentricity of planetary orbits measured, 17.
- Expansion, universal law of, 271;
- accuracy in measurement ensured by laws of unequal, 272;
- of crystals, 272, 273;
- theory of, 275, 277;
- of steam, 278;
- by electricity, 285.
- Extra-tropical winds, 124.
- Fabricius, the comet of 1556 observed by, 370;
- Fahrenheit, mode of ascertaining heights proposed by, 120.
- Falling stars, 420;
- Faraday, Dr., gases reduced to liquids by, 105;
- experiments testing chemical affinity, 111;
- instance of cohesive force inducing chemical combination, 112;
- experiments on vibrations producing colour, 173;
- influence of dialectrics, 286;
- chemical origin of electricity defended by, 300;
- electro-chemical decomposition defined by, 308;
- remarks of, on conduction of voltaic electricity, 309;
- experiments on magnetic rotation, 313;
- experiment magnetizing polarized light, 318, 319;
- importance of his experiment, 320;
- experiment establishing the identity of magnetism and electricity, 322, 323;
- his magnetic battery, 324, 325;
- aid given by, in construction of telegraphs, 326, 328;
- electricity produced by rotatory motion explained, 330;
- his classification of substances according to magnetic qualities, 332;
- quotation from, on conservation of force in electricity, 334;
- magnetism raised to a new science by, 335;
- the magnet as represented by, 338;
- experiment determining the forms of magnetic lines of force, 339, 340;
- accidental electro-magnetic combinations pointed out by, 342;
- his discovery of diamagnetism, 347;
- experiments on magnetic action in crystals, 349;
- observations on influence of heat in magnetism, 352;
- definition of gravity questioned by, 354, 355;
- magnetism of the ethereal medium tested, 356.
- Fauna, distinct, of separate regions, 254, 255.
- Faye, M., his conception of the sun’s constitution, 41;
- his theory of phenomena observed in eclipses, 42;
- comet of 1843 discovered by, 361.
- Fiedler, Dr., fulgorites exhibited by, 293.
- Fire, chemical combination producing, 270.
- —— balls, theory of, 421.
- Fires, central, subterranean, 231-237.
- Fish, phosphorescent, 294, 295;
- Fixed stars.
- Fizeau, M., decisive experiment in proof of the undulatory theory of light accomplished by, 202.
- Flame, chemical combination evolving, 270, 271.
- Flames, lambent, caused by electricity, 294.
- —— divergent from the nucleus of a comet, 364.
- Fletcher, Mr., periodic time of γ Virginis determined by, 398.
- Flora of the Himalaya, 250;
- distinct, in separate regions, 251;
- condition establishing distinct, in islands, 252.
- Florence, comet discovered from, 378.
- Fluor-spar, its property of diminishing refrangibility of light, 196.
- Fluorescence of light, definition of, 195;
- vibrations of the substance producing, 196;
- experiments, 197, 198.
- Focus of a meteoric shower, 422.
- Fog, yellow, excluding the chemical action of rays, 214.
- Forbes, Professor, temperature of the boiling point ascertained by, 120;
- observations of, on rayless lines, 163;
- lunar heat tested by, 227;
- experiments of, in polarization of heat, 264, 267.
- Force, relation of, to heat, 275;
- transforming solids to liquids and to vapour, 275, 277;
- a power of nature, 279;
- light and heat modes of, 219, 220;
- heat a living, 329;
- lines of magnetic, 338, 340;
- conservation of, maintained in periodic variation of atmospheric magnetism, 345;
- increatable, indestructible, 353;
- examples of conservation of, 354;
- fundamental principle of conservation, 357;
- influence and action of the gravitating, 424, 426.
- Forces, the unknown cause of motion, 5 et passim;
- counteraction of solar and tangential, in planetary motion, 8;
- adjustment of, ensuring the permanence of the solar system, 11, 12;
- three partial, causing perturbation in planetary motion, 14, 15;
- excess of equatorial diameter the origin of, 27, 28;
- three, disturbing lunar motions, 34, 35;
- determining planet forms, 44, 45;
- producing tides, 91, 92;
- combining to form the centrifugal, 100;
- acting on molecules of matter, 102, 105;
- producing capillary phenomena, 114;
- latent, in nature, 279, 280;
- one universal power, the root of all, 321;
- exact balance of, in electricity, 334;
- kindred and convertible, 353;
- developing comets’ tails, 375;
- determining the forms of orbits, 382, 383;
- maintaining the stability of the solar system, 426;
- mutual relations of, 427.
- Forests, change produced in the atmosphere by, 241, 243;
- number of species of trees found in American and European, 252.
- Formentera, quadrant of the meridian passing through, furnishing a unit of linear measure, 89.
- Fornix, nebulous patches crossing, 417.
- Forster, Lieutenant, conversation carried on by, across Port Bowen Harbour, 136.
- Fossil plants, an evidence of change in temperature, 74.
- Fourier, mean temperature of space according to, 119;
- rate of decrease in the earth’s central heat computed by, 232.
- Fox, Mr., temperatures in mines tested by, 228, 229;
- law of paramagnetic force ascertained by, 338;
- observations in mines, proving agency of electro-magnetism, 346.
- France, arcs of the meridian measured in, 48;
- unit of linear measure in, 89;
- mode of arithmetical computation, 90;
- atmospheric pressure in, 120;
- cliffs of, seen from Hastings, 157.
- Fraunhofer, M., discovery of rayless lines in the solar spectrum, 162;
- comparative refrangibility of rays ascertained by, 163;
- data furnished by, to determine the dispersive power of rays, 165;
- his discovery determining the length of waves independently of refraction, 201;
- spectrum of an electric spark observed by, 289.
- Freezing, temperature required for, under pressure, 271;
- Fresnel, M., his testimony in favour of the undulatory theory of light, 171;
- theory of refraction, 183;
- discoveries in polarization of light, 191, 193.
- Freyberg, green plants found in mines at, 253.
- Friction evolving heat, 274, 275;
- Fringes of coloured light bordering shadows, 174, 175;
- produced by interference of polarized rays, 194.
- Fulgorites, found in Silesia, 293.
- Fundy, the Gulf of, cross tides pouring into, 94.
- Gage, Mr., experiments of, on magnetism, 315.
- Gales.
- Galileo, laws affecting music discovered by, 145;
- his method of finding distances of fixed stars, 388.
- Galle, Dr., Neptune’s place communicated to, by Le Verrier, 62.
- Galloway, Mr., sun’s motion proved by, 405.
- Galvani, Professor, peculiar effects of electricity suggested to, 297.
- Galvanism, phenomenon suggesting the theory of, 297;
- batteries, 298, 300;
- heat and light evolved by currents of, 300, 304;
- decomposition and composition, 307, 308;
- applied to plating and gilding, 309;
- effect of heat on, 310;
- effect of, on the senses, ib.;
- fish exhibiting analogous phenomena, 310, 311;
- phenomena exhibited by currents of, on magnets, 312, 314:
- intensity of a current measured, 315;
- conditions obtaining a circuit in, 332.
- Galvanometer, the principle of its construction, 315;
- experiment by means of, identifying magnetism and electricity, 322, 323.
- Gambart, M., parabolic elements of a comet computed by, 367.
- Gamma Andromeda, colours of, 401.
- —— Aquarii, planetary nebula near, 412.
- —— Hydræ, a variable star, 391.
- —— Leonis, focus of a meteoric shower in, 422.
- —— Sagittarii, cluster of the Milky Way round, 387.
- —— Virginis, eclipse in, 397;
- orbit of the revolving star determined, 398.
- Ganges, the, tidal wave at the mouths of, 94.
- Gardner, Mr., extent of diametrically opposite lands estimated by, 244.
- Gases, conditions retaining matter in the form of, 104, 105;
- combinations of, 111;
- transmission of radiant heat through, 258;
- expansion of, 271;
- voltaic spectrum modified by, 303;
- effect of heat on the conducting powers of, 309.
- Gassiot, Mr., experiments of, on the electric discharge, 306;
- connexion between magnetism and light discovered by, 321;
- electric apparatus improved, 328.
- Geneva, the Lake of, experiment on the velocity of sound in, 135.
- Gensanne, M., increasing temperature of mines tested by, 228.
- Geographers, lunar motions important to, 42.
- Geological changes, probable cause of, 77.
- Geology, the lessons of, 326.
- Georgia Island, S., excess of cold in, over corresponding latitudes, 241.
- Germany, shooting stars seen from, 421.
- Gibraltar, the Straits of, turning aside the tidal wave, 98.
- Giromagny, temperature of the lead-mines of, 228.
- Glass, effect of cohesion on plates of, 106;
- musical notes elicited from rods and plates of, 144-147;
- transmission of waves of light in, 177;
- polarizing light, 184, 185;
- elliptical polarization produced by, 193, 194;
- used in photography, 207;
- impressions on, from bodies in contact with, 220;
- impressions on, traced by electricity, 221;
- transmission of radiant heat by, 259;
- by coloured, 261, 262;
- its temper altered by magnetism, 352, 353.
- Globular clusters of nebulæ, 413-415.
- Glow-discharge observed by Captain Bonnycastle, 295, 296.
- Gold, action of, on light, 173.
- Good Hope, the Cape of, icebergs drifted to, 101.
- Goodricke, Mr., variable stars discovered by, 391;
- opaque bodies represented as revolving round fixed stars by, 394.
- Graham, Mrs., account of an earthquake by, 234.
- Graham’s compensation pendulum, 272.
- Gravitating force of the sun, 365, 424, 425.
- Gravitation, offices of, in the material creation, 1, 2;
- process of reasoning in ascertaining the law of, 3;
- law determining its intensity in the solar system, 5;
- complex action of, by attraction in mass and in particles, 6;
- increase of, towards the poles of the earth, 45;
- calculations founded on its increase, 49-51;
- in a mine, its excess over surface, 57;
- action of, modifying tides, 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.
- Hail, formation of, 270.
- Hales, his calculation of the amount of surface exposed by the leaves of a helianthus, 243.
- Hall, Mr., achromatic telescope constructed by, 165.
- Halley, elements of a comet’s orbit computed by, 362;
- return of his comet, 363;
- changes in its aspect, 363, 364;
- records of, 365;
- no solid nucleus in, 374;
- cause of its luminous sectors, 376;
- Sir John Herschel’s observations on, 378.
- Hare, the, comet observed near, 372, 373.
- Harmonics of the fundamental note in music, 140, 141.
- Harmony, property of sound regulating, 131;
- definition of, vibrations producing, 142.
- Harris, Sir William Snow, experiments of, in electricity, 287, 288;
- lightning-conductors invented by, 293.
- Harrison, pendulum invented by, 272.
- Hastings, coast of France distinctly seen from, 157.
- Heat affecting the form of crystals, 107;
- evolved in chemical combinations, 110;
- irregular decrease of, in the atmosphere, 119;
- maxima of, in the solar spectrum, 215;
- peculiar chemical quality of, in parathermic rays, 218;
- impressions traced by, 220-222;
- periodical variations in the sun’s, 225;
- different proportions of solar, reaching the planets, 225, 226;
- effect of the terrestrial atmosphere on lunar, 227;
- mode of its development in opaque bodies, ib.;
- sources of terrestrial, 228-238;
- irregular distribution of, 239-247;
- laws affecting its radiation, 257;
- its transmission, 258-262;
- polarization of, 264-267;
- undulatory theory, 267;
- absorption and reflection of radiant, 268;
- phenomena caused by radiation of, 269;
- accumulation of, producing light, 270;
- expansive force of, 271, 272;
- modes of propagation, 273, 274;
- produced by motion and equivalent to it, 274-277;
- laws regulating the force of artificial, 279, 280;
- power evolved by application of, 280;
- identical in nature with sound, 281;
- electrical, 288;
- sheet-lightning caused by, 294;
- phosphorescence, 294;
- developed by voltaic electricity, 301, 302;
- effect of, on electrical conductors, 309;
- connexion between the production of electricity and, 310;
- its direct relation to magnetism and electricity, 319, 320;
- mechanical power and convertible forces, 329;
- terrestrial magnetism attributed to the action of, 333;
- measured by electric currents, 334;
- affecting atmospheric magnetism, 344;
- fundamental principle of the dynamic theory, 357.
- Helena, St., distinct flora of, 252.
- Helix, circular and elliptical, described in polarization of light, 192, 193;
- electrical experiments by means of, 314;
- induction of, increasing electric power, 322, 323.
- Heller, his observations on the comet of 1556, 370, 371.
- Helmholtz, Professor, power of chemical force estimated by, 112;
- his calculation of the chemical force developed by combustion, 278;
- of the amount of latent force in our system, 280.
- Hemisphere, cause of excess of cold in the southern, 241;
- superficial extent of land in northern and southern, 244.
- Henley, Mr., magneto-electric machine constructed by, 325.
- Henderson, Professor, parallax of α Centauri calculated by, 387;
- Henry, Professor, experiments of, on magnetism, 315.
- Herapath, Mr., his view of elastic force preferred to Sir Humphry Davy’s, 276.
- Hercules, eclipse of a double star in, 398;
- globular nebulous cluster, 414.
- Herschel, Sir William, observations of Saturn’s and Uranus’s satellites by, 32, 33;
- theory of, regarding the solar constitution, 41;
- cause of effects of light in eclipses according to, 42;
- rotation of Jupiter’s satellites determined by, 70;
- mutual independence of light and heat, 214, 215;
- influence of the sun’s spots on heat, 225;
- point of maximum heat in the solar spectrum, 263;
- comet of 1811 observed by, 374;
- its luminous envelopes examined, 375;
- the Milky Way examined by, 385;
- his discovery of the orbital motions of double stars, 388;
- catalogue of double stars by, 395, 396;
- periodic time of γ Virginis determined by, 398;
- eclipse of a double star observed, ib.;
- binary system discovered, 400;
- remarks on the motions of the stars, 405;
- nebulæ resolvable into stars, 507.
- Herschel, Sir John, approximate periods of satellites ascertained by, 33;
- thickness of Saturn’s ring computed, 67;
- observations of, on seasons, 74;
- difficulty of varying time, in observations at distances, obviated by, 86;
- tenuity of atmospheric air demonstrated, 110;
- rapid decrease of density in the atmosphere, 118;
- mean temperature of space computed by, 119;
- height of Etna measured, 120;
- his explanation of anomalies in atmospheric phenomena, ib.;
- quotation from, on the transmission of sound, 136;
- observations of, on thunder, 138;
- remarks on the absorption of light by coloured media, 175, 176;
- on polarization of light, 179;
- experimentalising apparatus, 188;
- discovery of epipolic light, 197;
- discoveries in photography, 205, 206;
- analysis of the solar spectrum, discovery of its chemical properties, 207-219;
- his theory of volcanic action, 235-237;
- observations showing the maximum of heating influence of the solar rays, 238;
- theory of the original distribution of plants, 254;
- divergent flame of a comet observed by, 364;
- remarks on the possible destruction of the solar system, 372;
- causes assigned by, for contraction of diameter in comets, 378;
- comparative lustre of stars measured by, 384, 385;
- the Milky Way described, 385, 386;
- number of stars in a group of the Milky Way computed, 387;
- variable star discovered, 391;
- remarks of, on the nature of the fixed stars, 392;
- variable stars discovered by, 393;
- remarks on variable stars, 394;
- star missed by, 395;
- double stars discovered, 396;
- eclipse of a double star observed, 397;
- orbits determined, 398, 399;
- observations on colours of double stars, 401;
- light of α Centauri compared with the moon’s by, 404;
- light of the fixed stars calculated, ib.;
- observations on nebulæ corrected, 407;
- catalogues of nebulæ, 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 η 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.;
- their extent and velocity, 126,127;
- phenomena resulting from their revolving motion, 127;
- laws of, making avoidance possible, 128.
- Huygens, theory originated by, 169.
- Hydrogen, proportion of, in water and gases, 111;
- spectrum from, 303;
- separated from water by electricity, 307.
- Hygrometer, dew-point measured by, 269.
- Hyperbolic motion, ratio of forces procuring, 382.
- Iapetus, seen by Mr. Lassell, 33.
- Ibn Junis, progress of science in his time, 90.
- Ice, formation of, 271;
- force acting in its formation, 276;
- stopping the current of voltaic electricity, 309.
- Icebergs, drifting of, 100, 101;
- farthest range of northern and southern, 241;
- effect of electricity in collisions, 284.
- Iceland spar, its property of double refraction, 181;
- polarized ray analyzed by, 187;
- transmission of radiant heat by, 258;
- electricity elicited from, 284.
- Illumination, comparative, of objects, experiments determining, 227.
- Images, coloured, of the solar spectrum, 208-211;
- traced by contact and juxtaposition of bodies, 219, 220;
- by electricity, 221;
- by media absorbing hot rays, 222.
- India, arcs of the meridian measured in, 48;
- discovery of Saturn’s ring, 66;
- ancient monument of astronomical knowledge, 85;
- observations confirming the antiquity of astronomical science in, 88.
- Indian Ocean, the tidal wave in, 94;
- monsoons blowing over, 124.
- Induction, law of, in electricity, 285, 286;
- magnetic, 314, 315;
- phenomena of, produced by electric currents, 324;
- illustrated by the Atlantic telegraph, 325, 326;
- velocity of electricity modified by power of, 327;
- possibility of electro, furnishing a motive power, 328;
- of electricity by rotation of magnets, 330-332;
- as possessed by magnets, 336;
- paramagnetism evolved by, 337;
- means of accelerating, ib.;
- subject to the laws of mechanics, 338;
- analogy between electric and magnetic, 341;
- of heavenly bodies, affecting terrestrial magnetism, 346, 347;
- diamagnetic substances capable of, 348.
- Indus, comet passing through the constellation of, 379.
- Inequality, the, of Jupiter and Saturn marking historical epochs, 88.
- Insects, law of their dispersion, 255.
- Instruments, musical, 143, 149, 150;
- imitating articulation of letters, 151, 152.
- Insulation in electricity, 285.
- Interference, laws of, neutralizing undulations, 138, 139;
- the theory of, referred to a general law, 169.
- Iota Cetæ, comet observed near, 372.
- —— Orionis, a nebulous star, 411.
- Ireland, progress of the tidal wave towards, 94.
- Iron, distilled, 305;
- rotation of its particles, ib.;
- magnetized by electricity, 314, 315;
- magnetic properties of, 332;
- rendered paramagnetic, 336, 337;
- magnetic and electric properties of, 347;
- elasticity of, affected by magnetism, 352.
- Islands, character of their floras, 252.
- Isogeothermal lines of temperature defined, 238, 239;
- parallel with the isothermal lines, 246.
- Isomorphous crystals, 109.
- Isothermal lines of temperature defined, 240;
- latitudes of, deviation from the line of the equator, 245;
- formula determining, 246;
- similarity of vegetation in the same, 253.
- Italy, local attraction, occasioning inaccuracy in measurement, 48.
- Ivory, M., his method of computing heights, 120;
- his theoretical investigation of planet forms, 44;
- deduction from measurement of arcs of the meridian, 48.
- Jacob, Mr., discovery of Saturn’s ring by, 66;
- periodic time of α Centauri determined by, 399;
- periodic time of 70 Ophiuchi, 400.
- James, Colonel, measurements of, in the General Survey of Great Britain, 47;
- density of the earth determined by, 58.
- Jamin, M., remarks of, on substances producing elliptical polarization, 193.
- January, epoch of its beginning the year, 85.
- Jews, denominations of time in their calendars, 85.
- Josephstadt, discovery of a comet from, 367.
- Joule, Mr., heat considered a mechanical force by, 275;
- his view of elastic force, 276;
- amount of latent force in a pound of coal, computed by, 278;
- furnishing data to Professor Thomson, 279;
- quantity of heat generated in a unit of time by electricity computed by, 302;
- powerful magnet obtained by electricity, 315;
- electric machines constructed by, 328;
- experiments proving heat and mechanical power convertible, 329.
- Jovial system, mass of the whole, 55.
- Julian Calendar, year of, the first of our era, 86.
- June, 1833, reappearance of Saturn’s rings, 67;
- coincidence of times in, 84.
- Juno, the diameter of, 56;
- astronomical tables of, 63.
- Jupiter, rotation of, distinguished from the other planets, 7;
- periodical inequality in his motions, 15;
- discovery of telescopic planets between Mars and, 20, 21;
- diameter of, 21;
- his position with respect to the equator of the solar system, 24;
- inequalities in the motion of, apparently anomalous, 25, 26;
- his mass proved not homogeneous, 29;
- eclipses, 30, 31;
- compression of his spheroid computed, 39;
- eclipsed by Mars, 42;
- mass of, compared with the sun, 55;
- his diameter, 56;
- increase of density in, 58;
- astronomical tables of, 60;
- rapid rotation, 66;
- period of a year in, ib.;
- effect of his disturbing energy, 81;
- photographic images of, 226;
- light reflected by his atmosphere, 227;
- action of, on the comet of 1770, 361, 362;
- on Halley’s comet, 362, 363;
- comet revolving between the orbits of the earth and, 367;
- future influence of, on comets, 369;
- comet nearly approaching his fourth satellite, 370;
- comets having their perihelia in his orbit, 381.
- ——, orbit of, revolutions of its major axis, source of variation in excentricity, 17;
- slow revolution of its nodes, decrease in its inclination to the ecliptic, 19.
- —— with his satellites, an epitome of the solar system, 27;
- effect of his excessive equatorial diameter on their orbits, 28;
- satellites, libration in, 69;
- rotation of, 70.
- Kane, Dr., Polar Sea discovered by, 94;
- cold of Northern Greenland marked by, 247.
- Kappa Crucis, cluster of coloured stars round, 419.
- —— Draconis, seen in the pole of the equator, 88, 89.
- Karsten, Mr., impressions made on glass by electricity, 221.
- Kasan, summer and winter mean temperature of, compared with Edinburgh, 246, 247.
- Kater, Captain, approximate length of the pendulum, determined by, 89.
- Kempelen, M., speaking-machine invented by, 151.
- Kepler, paths, revolutions of planets discovered by, 5;
- his law regarding the mean distances of planets from the sun, 19;
- law of, applied to calculating distances, 53, 54;
- rapidity of planetary revolutions determined by his law, 66;
- his law finding areas described by heavenly bodies, referred to, 360.
- Kew, balloon ascent from, 119.
- Knoblauch, position of the magnecrystallic axis proved by, 349.
- Knowledge, limited nature of human, 2.
- Kotzebue, stratum in the ocean discovered by, 101.
- Kratzenstein, M., instrument invented by, articulating words, 151.
- Kupffer, M., observations of, on temperature, 246.
- La Basilicata, earthquake in, 234.
- Lacaille, his globular nebulous cluster, 414;
- La Grange, his investigations into the stability of the solar system, 20, 21;
- greatest discovery of, 23.
- La Hire, phases in comets observed by, 380.
- La Place, stability of the solar system proved by, 20;
- principle in astronomical calculations established, 23;
- angle of inclination fixed, 24;
- his theory accounting for acceleration in the moon’s mean motion, 36, 37;
- result of observations compared with his theory of Jupiter’s satellites, 55;
- theory of planetary motion, 65, 66;
- universal epoch proposed by, 87;
- scientific observations complementing historical records, 87;
- date fixed by, for the lunar tables of the Indians, 88;
- justifies Newton’s theory of tides, 96;
- density of a liquid column estimated by, 114;
- action of the earth on a comet, 359;
- change in a comet’s orbit, 361;
- cause of error in Clairaut’s calculation pointed out by, 363;
- opinion of, as to the comet of 1682, 378.
- “Lake of the Gazelles” ascribed to an effect of reflection, 157.
- Lalande, epochs of conjunctions computed by, 42.
- Lambda Herculis, general motion of the stars determined by, 405.
- Land, dry, comparative extent of, on the globe, 242, 244;
- extent of, in diametrical opposition, 244.
- Landscapes in chiaroscuro, produced by photography, 207.
- Languages, resemblances and analogies between, 255, 256.
- Lapland, arcs of the meridian measured in, 48;
- transit of Venus observed in, 53.
- Laroche, M., his experiments on transmission of radiant heat, 259, 261.
- Lassell, Mr., satellite of Saturn discovered by, 32;
- observations of, on Uranus’ satellites, 33;
- his discovery of Neptune’s satellite, ib.;
- observations on Saturn’s rings, 66.
- Latent heat, energetic action of, on matter, 275-277.
- Latitude, the, of a planet defined, mode of obtaining, 9, 10;
- cause of periodical inequalities in, 15;
- perturbations from action of the perpendicular force, 18;
- moon’s motion in, disturbed, 35;
- effects of disturbance, 38;
- data of, used in computing a planet’s place in the heavens, 58-60;
- conditions ensuring the invariability of geographical, 76, 77;
- change effected by nutation in, 81;
- climate not invariable in the same, 239;
- degrees of, where diminution of mean heat is most rapid, 244, 245;
- the same mean temperature in different, 246, 247;
- of wine-growing, 250;
- magnetic storms varying with, 345.
- Layang, observations made at, 1100 years before the Christian era, 88.
- Le Sueur, specific diversity of marine animals observed by, 254.
- Le Verrier, M., principle of La Grange applied by, 21;
- zone of instability found, ib.;
- discovery of Neptune, 62;
- his observations on atmospheric waves, 122;
- comets identified by, 362;
- his table of comets’ orbits, ib.
- Lenticular nebulæ, 409;
- haze surrounding the sun, 412.
- Leo, nebulous system in, 417.
- Léon-Faucault, M., velocity of light in air and water ascertained by, 202.
- Lerius, banks of algæ found by, 253.
- Leslie, Professor, compression of air calculated by, 78;
- experiments on radiation of heat, 257.
- Lexel, observations of, on the comet of 1770, 361, 362.
- Libra, the five great planets in conjunction near, 42.
- Librations of the moon, of Jupiter’s satellites, 69;
- Lichen, red, growing on snow, 249.
- Light, rate of its velocity, 31;
- truth deduced from the uniformity of its velocity, 32;
- from the aberration of, ib.;
- period required to reach the earth from α Centauri, 54;
- action of the atmosphere on, 153;
- conditions regulating the transmission and reflection of, 156;
- loss of, transmitted by the horizontal stratum, 157;
- effects of transmission through the atmosphere, 158;
- Newton’s analysis of, 159;
- Brewster’s, 161;
- phenomena disproving Newton’s theory, 167, 168;
- undulatory theory, 168-170;
- conditions affecting its intensity and colour, 170;
- experiments testing the mutual relations of colour and, 171-175;
- law of its absorption identical with a law of motion, 175-177;
- repeated vibrations producing the sensation of, 178;
- polarized, defined, 179;
- modes of polarization, substances polarizing, 179-185;
- accidental polarization of, 195;
- degraded, or fluorescence, 196;
- objections to the undulatory theory analyzed and disproved, 199-202;
- comparative velocity of, in air and water, 202;
- pictures produced by reflected, 203-207;
- rays of, independent of heat, 214, 215;
- comparative amounts of solar and lunar, 225;
- different measures of illumination from, 227;
- influence of, on vegetation, 249;
- colour developed without the influence of, 253;
- separated from heat by Melloni, 265;
- produced by accumulation of heat, 270;
- law regulating the force of artificial, 279, 280;
- electrical, 288, 289;
- produced by voltaic electricity, 302;
- stratifications of the electric, 306;
- influence of magnetism and electricity on, 319, 320;
- of comets, 379-381;
- of the fixed stars, 401-404.
- Lightning, development of heat exhibited by, 276, 277;
- experiment showing the velocity of, 289;
- theory of, 292;
- the back stroke, ib.;
- force of the direct stroke, 293;
- sheet, 294;
- effect of, on the compass, 312.
- Lime, carbonate of, variety of form in its crystals, 107;
- invariable form ultimately assumed by, 109.
- Lines of magnetic force, 338, 339;
- experiment ascertaining the form of, 339, 340;
- terrestrial, 341, 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, 349;
- temperature affecting, 352.
- Magnetic bodies, difference in power of, 347.
- —— elements, the three terrestrial, 343.
- —— equator of the earth, 343.
- —— meridian, the, mean action of forces determining, 343.
- —— poles of the earth, 343.
- —— storms, 344;
- varying with latitude, 345, 346.
- Magnetism, source of, 318;
- producing electrical phenomena, 322, 323;
- rotatory motion a source of, 330;
- classification of substances, with regard to their susceptibility of, 332;
- residing in substances after two manners, 335;
- experiment illustrating the forces of, 338;
- antithesis, its general character, 339;
- form of its lines of force, 339, 340;
- analogous properties of electricity and of, 340, 341;
- terrestrial, 342-347;
- connexion between solar and terrestrial, 344;
- action of, in crystals, 349-351;
- influence of temperature in, 352;
- affecting elasticity of matter, 352, 353;
- a property of the ethereal medium (?), 356, 357.
- ——, electro, discovery, importance of the science, 312;
- rotation effected by, 313, 314;
- electric intensity measured, 315;
- action of currents in, defined, 316;
- Ampère’s theory of, 317, 318;
- causing rotation of polarized rays, 319;
- action of, on light, 320;
- accidental combinations, 342;
- influencing metalliferous deposits, 346.
- Magneto-electricity, principle suggesting, 322;
- machine constructed on the principle of, 325;
- relation of heat to, 329.
- Magnets, influence of, on electric light, 307;
- fish possessing the power of making, 311;
- effect of an electric stream on, 312-314;
- obtained by electricity, 315;
- power of electro, measured, 315;
- cylinders acting as, 316, 317;
- producing electrical effects, 322, 323;
- evolving electricity by rotation, 330;
- classification of substances in relation to, 332;
- polarity a property of, 336;
- effect on themselves of imparting paramagnetism, 337;
- experiment showing the lines of force of, 338;
- properties of, indestructible by subdivision, 338, 339;
- the earth reckoned among, 342;
- planets reckoned among, 346;
- action of an electro, on copper, 351.
- Maguire, Captain, his observations on magnetic storms, 345, 346.
- Malo, St., rising of the tide at, 98.
- Malus, M., discovery of polarization of light by, 195;
- attempts of, to polarize heat, 264.
- Malta, observations on Saturn’s rings made at, 66.
- Manchester, thunderstorm near, in 1835, 292.
- Mankind, distinct tribes of, 255;
- limited perceptions of, 267.
- Marcet, M., rate of increase in temperature below the earth’s surface calculated by, 230.
- Marco Polo, atmospheric effects observed by, in ascending mountains, 118.
- Marine plants, laws regulating their distribution, 252, 253;
- animals, specific localities of, 254.
- Mariner’s compass.
- Mars, used in illustrating the possible effects of the radial distributing force, 19;
- telescopic planets between Jupiter and, 20, 21;
- diameter of, 21;
- mean distance from the sun, ib. note;
- eclipse of Jupiter by, 42;
- parallax found by observing his oppositions, parallax of, 53;
- internal structure, 58;
- astronomical tables of, 63;
- climate of, 225;
- approach of the comet of 1770 to, 362;
- comets having their perihelia in his orbit, 381.
- Marseilles, transit of a comet across the sun observed from, 374.
- Masses, of the sun, of planets and their satellites, computations finding, 55, 56.
- Mathematics, use of, in the study of astronomy, 2.
- Matter, theory of its constitution, 102;
- hypotheses as to forces uniting its particles, 103, 104;
- counterbalancing action of elasticity and cohesion, 105;
- crystallization common to all forms of, 109;
- indestructibility of its particles, 110;
- composition of unorganised bodies, subject to permanent law, 110, 111;
- agent composing or decomposing, 112;
- mode of ascertaining the magnetism of, 335;
- increatable, indestructible, 353;
- proportion of, to spare, 424.
- Matteucci, M., effect of electricity on polished silver observed by, 221;
- experiment showing polarization by electricity, 286;
- doubts of, on the polarity of diamagnetism, 348 note;
- experiments on magnetic action in crystals, 350;
- observation on the action of compression, 352.
- Maury, Lieutenant, calms named by, 123.
- Measurement of astronomical distances, formula assisting, 43.
- Mechain, M., Encke’s comet seen by, 365.
- Mechanical equivalent of heat, 275.
- —— engines, incapable of generating force, 279.
- Mediterranean, the, conditions of, shutting out the tidal wave, 98;
- hurricane in, divided into two storms, 126;
- vegetation of, 252.
- Medium, ethereal, transmitting magnetism, 344;
- density of, 356;
- probable relations of, to gravity, ib.;
- experiment testing its magnetic properties, 356, 357;
- functions of, 357;
- pervading the visible creation, 358;
- unsolved question touching, 365;
- a cause of accelerated revolutions of comets, 366, 367;
- direction of its increase in density, 367.
- Medium occupying space, 424.
- Medusa tribes, the, phosphorescent brilliancy of, 295.
- Melloni, M., experiments of, in photography, 214;
- his application of the principle of thermo-electricity, 333;
- experiments of, in transmission of heat, 258-263;
- fixing the maximum of heat in the solar spectrum, 264;
- in polarization of heat, 264-266;
- light separated from heat by, 265.
- Melville Island, height of the thermometer in, in January, 247.
- Mercury, inclination of his orbit to the plane of the ecliptic, 21;
- eclipse of, 42;
- cause of his rotation unknown, 65;
- ellipticity of his orbit compared with the terrestrial, 74;
- climate of, 226;
- comet revolving between the orbits of Pallas and, 367;
- attraction of, determining a comet’s orbit, 369;
- comets revolving in his orbit, 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, 417;
- great nebula in, 418;
- remote branches of, 419.
- Minerals, possessing the phosphorescent property, 294.
- Mines, cause of increased temperature in, 229;
- green plants growing in, 253.
- Mira, periods of its fluctuations in lustre, 390.
- Mirage, supposed cause of, 157.
- Miraldi, rotation of Jupiter’s satellite determined by, 70.
- Mitscherlich, M., his experiments on crystals, 107;
- discoveries, 108;
- experiments of, in expansions of crystals, 272.
- Mocha, meteors falling at, 421.
- Moignot, M., crystals compressed by, 189.
- Moisture, an indispensable requisite for vegetation, 248;
- transmission of electricity effected by, 284, 288.
- Molecular polarity, produced by electricity, 282;
- attraction, electricity developed by destruction of, 284.
- —— structure affecting transmission of electricity, 303.
- —— vortices, hypothesis of, accounting for the absorption of light, 177.
- Molecules, material, attraction and repulsion of, 103;
- effect of elasticity and cohesion on, 104-106;
- uniting to form crystals, 107-109;
- extreme minuteness of ultimate, 110;
- of ether, modes of their vibration in natural and polarized light, 193;
- in fluorescent light, 196, 197;
- images traced by the mutual action of, 219-222;
- arrangement of, connected with magnetism, 350-352.
- Mollusks, distinct species of, 254.
- Monocerotis 11, a triple star, 395.
- Monsoons, theory of the, 123, 124.
- Months, antiquity of, as a measure of time, 85.
- Moon, the, force restraining, 4, 5;
- mean distance of, from the earth, 4;
- results effected by her nearness to the earth, 7;
- annual rate of decrease in her orbit’s excentricity, 17;
- average distance of, from the earth’s centre, period of her circuit of the heavens, 34;
- her periodic perturbations, 35-38;
- causes assigned for acceleration of her mean motion, 36, 37;
- eclipses of, 39, 40;
- longitudes determined by observations of, 42, 43;
- her mean horizontal parallax, 52;
- sources whence her mass may be determined, 55, 56;
- her diameter, 56;
- rotation of, 68;
- librations, 69;
- mountains, 70;
- precession resulting from her attraction, 79-81;
- influence of, producing tides, 91, 92, 96-98;
- period of her declinations, 97;
- atmospheric equilibrium disturbed by her attraction, 121;
- cause of her apparent increased magnitude in the horizon, 158;
- photographic image of, 214;
- comparative amount of light emitted by, 225;
- cause of the rarity of her atmosphere, 226;
- increased intensity of light at full, ib.;
- effect of the terrestrial atmosphere on heat radiated from, 227;
- cause of acceleration in the mean motion of, 366;
- light reaching the earth from, 404.
- Moorcroft, herbarium collected by, 250, 251.
- Moser, Professor, mutual influence of bodies in contact tested by, 219, 220.
- Mossotti, Professor, his analysis to prove the identity of the cohesive force with gravitation, 103, 104;
- his definition of gravity, 355.
- Motion, a law of the universe, 274;
- perpetual, impossible, 279.
- Mountains, anomalies in measurement caused by, 48;
- rarity of atmosphere on, 118;
- cause of perpetual snow, 119;
- modes of determining heights of, 120;
- becoming new centres of motion in hurricanes, 126;
- influence of chains on temperature, 241, 242;
- cause of éboulemens in, 271;
- tops of, fused by lightning, 293.
- ——, lunar, effect of solar rays passing between, in eclipses, 41;
- influence of, on the moon’s motions, 96;
- three classes of, 70.
- Mu Herculis, direction of solar motion with regard to, 406.
- Multiple systems of stars, 395.
- Mundy, Captain, mirage described by, 157.
- Music, comparison instituted of sympathetic notes in, 2;
- regulated undulations of sound producing, 142;
- instruments of, 143;
- experiments by means of vibrating plates, 144-146;
- sympathetic vibrations, 147, 148;
- experiments showing, 148, 149.
- Musical instruments constructed by Professor Wheatstone, 143.
- Naples, comet discovered from, 370.
- Nautical Almanac, computations for calculating longitudes, 43;
- Navigation, importance of lunar motions in, 42;
- laws of storms to be observed in, 127, 128.
- Neap-tides, 96, 99.
- Nebulæ, number and general aspect of, 407;
- catalogues, 407, 408;
- classes, 408;
- irregular, 408, 409;
- of definite form, 409;
- spiral, 409, 410;
- annular, 410, 411;
- elliptical, double, 411;
- distance of a nebulous star discoverable, 411, 412;
- aspect and colour of planetary, 412;
- elliptical common, 413;
- globular clusters, 413-415;
- resolution of, 415;
- star clusters, 415, 416;
- probable law of motion, 416;
- distribution of, 416, 417;
- the Magellanic clouds, 417, 418;
- round η Argûs, 418, 419;
- remote systems, 419;
- invisible solar, 421;
- meteors falling from, 422.
- Nebulous appearances of a comet, 364;
- extent of, matter surrounding a comet, 373;
- its variable brilliancy, 374;
- appearances round the sun, 412.
- —— stars, 411, 412.
- Needle, magnetized, effect of Voltaic electricity on a, 312, 313;
- suspended by means of electricity, 314;
- condition of its deviation by an electric current, 317.
- Negative electricity defined, 282;
- —— impressions in photography, 204.
- Neptune, periodical variations in his orbit, 22;
- revolution of his satellite from east to west, 33;
- remoteness of, 54;
- anticipation of discovery, 61;
- orbit and motions of, determined, 62;
- his diameter, mean distance from the sun, 63;
- temperature of, 225;
- action of, on Halley’s comet, 363.
- Neutral phosphate of soda, its crystals, 109.
- New Mexico, monsoons occasioned by its deserts, 124.
- Newton, Sir Isaac, steps of his argument for the universal influence of gravitation, 3;
- his discoveries of modes of attraction, 4;
- motions of bodies projected in space, ascertained by, 5;
- form of a fluid mass in rotation ascertained, 45;
- problem occupying astronomers since, 64;
- discrepancy between his theory of tides and observations, 96;
- compound nature of white light proved by, 159;
- his analysis of the solar spectrum disputed, 161;
- his theory of light disproved, 167;
- measurements of coloured rays, 172, 173;
- scale of colours, 174;
- decisive experiment disproving the theory of light, 202;
- remarks on the transmission of gravity, 355.
- Niagara, the falls of, not independent of the influence of astronomy, 1.
- Nickel, sulphate of, change in its crystals, when exposed to the sun, 107.
- Niepcé, M., photographic pictures rendered permanent by, 204;
- discovery in photography suggested, 207;
- colours of images of the sun taken, 213;
- experiments by, on saturation of substances with light, 296.
- Nimes, discovery of a telescopic planet at, 21.
- Nitrogen, proportion of, in the atmosphere, 117;
- spectrum from, 303;
- iron volatilized by the Voltaic arc in, 304;
- unaffected by magnetism, 344.
- Nobili, M., direction of electric currents ascertained by, 333.
- Nodes, ascending and descending, of a planet defined, 9;
- movement of their lines in secular disturbances, 14;
- advance and recession of, 18;
- supposed recession of, on the equator of the solar system, 24;
- of the moon, period of their sidereal revolution, 37;
- secular inequality affecting, 38;
- influence of, on eclipses, 39;
- cause of their rapid motion, 55;
- points of rest on a vibrating string, 141;
- in the vibrations of an undulating column of air, 142;
- in vibrations of solids, 147.
- Non-conductors of electricity, 284, 285.
- Non-electrics, 285.
- North Atlantic, the, winds in, 124.
- —— Polar Ocean, tide in the, 94.
- Norway, course of the tidal wave to, 94.
- Notes in music, 142, 143.
- Nubecula, Major and Minor, 417, 418.
- Nucleus, of Halley’s comet, changes in its aspect, 364;
- disappearance of, in Encke’s, 369;
- division, in Biela’s, 369, 370;
- diaphanous, 373;
- solidity of, tested, 374;
- of a spiral nebula, 409.
- Nuremburg, observations on a comet from, 370.
- Nutations produced by the moon’s nearness to the earth, 7;
- in Jupiter’s equator, 29;
- in the planetary axes, 66;
- effect of, on the pole of the equator, longitudes and latitudes altered by, 81.
- Nysa, nearness of its orbit to the earth, 21.
- Oaks, range of, near the equator, 250.
- Occultation, central, by Halley’s comet, 364;
- geographical position ascertained by, 384;
- prospective, by a sun of α Centauri, 400.
- Occultations of stars, 42, 43.
- Ocean, the, density and mean depth of, 51;
- mean density, compared with the earth’s, 77;
- its form in equilibrio, when revolving round an axis, 92;
- solar and lunar attraction disturbing its equilibrium, ib.;
- inequalities in periodic motions, 93;
- motions of the tidal wave in 95;
- stability of its equilibrium, 100;
- circulation of currents in, ib.;
- stratum of constant temperature in, 101;
- zones of, ib.;
- decrease and increase of temperature with depth, 231;
- absorption and radiation of heat by, 242;
- electricity evolved from, 291.
- Oceans of light and heat, processes producing, 225.
- Ochotzk, the sea of, depression of the barometer observed in, 120.
- October, 1832, position of Saturn’s rings in, 67.
- Olbers, M., computations for a comet by, 367;
- period of his comet, 370;
- comet of 1811 observed by, 374.
- Opaque bodies, mode in which heat is developed in, 227.
- Ophiuchi 70, anomalies in the motions of, 400.
- Ophiuchus, clusters of the Milky Way between the Shield and, 387;
- new star disappearing from, 393.
- Optic axis, the, of crystals, 183;
- phenomena exhibited by transmission of a polarized ray along, 187, 188;
- affected by compression, 189.
- Orbit, the, of the earth, attraction intensified by its diminished excentricity, 37;
- excentricity of, affecting temperature, 74, 75;
- crossed by comets, 368.
- —— of the moon, force ruling, 4;
- its excentricity, 34;
- changes in, 35;
- its inclination to the plane of the ecliptic, 79.
- —— of a nebula, 415.
- —— of the solar system, 405, 406.
- Orbits of comets, subject to variation, 361;
- examples, 361-363;
- prospective changes in, 369, 370;
- of Donati’s, 379;
- forces determining their forms, 382, 383.
- —— of double stars, 396-400.
- —— of planets, force regulating a planet’s velocity in, 8;
- measurement of their excentricity, 9;
- seven elements of, determining their position in space, 10;
- unequal movements in, 15;
- variation from elliptical to circular, 17;
- secular variations of, in inclination to the plane of the ecliptic, 18, 19;
- stable and unstable in form, 21, 22;
- influence of the ethereal medium on, 22;
- principle facilitating observations on secular inequalities, 23, 24;
- revolutions of Saturn compared with Jupiter, 25;
- periodic inequality increased by secular variations in their elements, 26;
- comets revolving in, 381, 382;
- cause of diversity in form of, 382.
- Orbits of satellites, forms of Jupiter’s, 27;
- their inclinations, 28;
- inclinations of Saturn’s, 32;
- positions of Uranus’s, 33;
- forms of data in computing a planet’s place in the heavens, 59.
- Orinoco, the cataracts of the, heard by day and by night, 135;
- area occupied by forests on, 243.
- Orion, the Milky Way between Antinous and, 385, 386;
- position of, 390;
- variable star in, 393, 394;
- multiple system in, 395;
- nebula in, 408.
- Oersted, Professor, discovery of, suggesting the theory of electro-magnetism, 312;
- science founding the reputation of, 316.
- Oscillations, wide-spreading, produced by gravitation, 2;
- mechanical principle affecting small, 11;
- of the sines and cosines of circular arcs, 20;
- invariable plane whence they may be estimated, 24;
- of the pendulum retarded, 32;
- of the pendulum, experiments founded on, 50, 51;
- experiments testing the earth’s density, 57;
- a measure of time, 83;
- produced by tides, 95, 96;
- instruments measuring atmospheric, 113;
- barometer affected by periodic atmospheric, 120, 122;
- of ears of corn, 129, 130;
- producing musical notes, 140-142;
- instances of forced sympathetic, 148;
- causing vicissitudes in climates, 247;
- of the pendulum, disturbed by effects of temperature, 272;
- measuring variation of electrical intensity, 287.
- Otto, M., motions of the heavenly bodies observed by, 405.
- Oxidation of metals, electricity developed by, 298;
- by the Voltaic discharge on polished silver, 305.
- Oxides decomposed by electricity, 307;
- alkalies resolved into metallic, 307.
- Oxygen, in crystals, 109;
- proportion of, in water and carbonic oxide, 111;
- in the atmosphere, 117;
- chemical combination with, evolving light and heat, 270;
- action of electricity on, 284;
- electricity afforded by combination of metals with, 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, 50;
- the earth’s figure calculated by, 50, 51;
- experiments ascertaining the earth’s density, 57;
- isochronous, a measure of time, 83;
- a standard of the measure of extension, 89;
- the, a connecting link between time and force, 94;
- inventions to neutralise the effects of temperature, 272.
- Penumbra, in lunar eclipse, breadth of space occupied by, 40.
- Perigee, of the lunar orbit, period of its revolution, 37, 38;
- cause of its rapid motion, 55.
- ——, solar, periods of its coincidence with the equinoxes, 86.
- Perihelion of a planet’s path defined, 16.
- —— of the earth’s orbit, its position regulating the length of seasons, 74.
- Periodic inequalities of planets, 13, 14;
- law from which they are deduced, 24, 25;
- of Jupiter’s satellites, 28, 29;
- lunar, 35.
- Perkins, Mr., experiments of, testing the laws of compression, 78.
- Peron, M., specific diversity of marine animals asserted by, 254.
- Perpendicular force, the source of periodic inequalities, 15;
- Perpetual motion, invariable proportion between heat and force precluding, 279.
- Perseus, variable star in, 390, 391.
- Peters, Mr., comet discovered by, 370;
- parallax of α Lyræ, 388, 389;
- distances of fixed stars calculated, 389;
- his theory of Sirius’ irregular motions, 392;
- sun’s motion proved by, 405.
- Petit, M., observations of, on meteoric satellites, 423.
- Peru, arcs of the meridian measured in, 48.
- Phases of the moon, regulating returns of eclipses, 39.
- Phenomena, of effects of light in eclipses, 41, 42;
- applied to computing longitudes, 43;
- caused by tidal oscillation, 96;
- from force of cohesion, 106, 107;
- of capillary attraction, 115;
- produced by refraction and reflection, 155-157;
- by polarization of light, 186-190;
- exhibited in fluorescence of light, 196, 197;
- resulting from interaction of rays and molecules, analogous to effects of photography, 219-222;
- phosphorescent, 295, 296;
- of galvanism, 310;
- of magnetism, 335, 345-348;
- magnecrystallic, 349, 350;
- exhibited by comets, 363, 364, 369, 370, 372-376;
- by the Milky Way, 385-387;
- by variable stars, 390-393;
- by double stars, 397-401;
- by nebulæ, 409-415, 417-419;
- by meteoric showers, 421, 422.
- Phosphorescence, rays of the solar spectrum exciting, 216;
- cause of, in the solar spectrum, 217;
- excited by electricity, 294;
- fish possessing the property of, 295;
- the glow discharge, 295, 296;
- experiments investigating the nature of, 296.
- Photo-galvanic engraving, 309.
- Photography, first suggestions, 203;
- discoveries and improvements in, 204-207;
- conditions affecting the chemical properties of rays producing, 207, 208;
- images of the solar spectrum obtained by, 208-210;
- coloured copy of an engraving, 211;
- phenomena in, suggesting an absorptive action in the solar atmosphere, 212, 213;
- chemical energy producing, distinct from light and heat, 214;
- experiments by means of, testing the properties of rays, 218, 219;
- experiments on action of light, heat, electricity, producing results analogous to effects of, 219-223.
- Photosphere, the, of the sun described, 224.
- Physical Sciences, the most extensive example of their connection, mode of its operation, 1.
- Pi Herculis, direction of solar motion with regard to, 406.
- Pisces, nebulous region of, 417.
- Planetary motion, representation of, 14.
- —— nebulæ, 409;
- Planets, paths round the sun described by, 5;
- law determining their revolutions, ib.;
- forces adjusting their forms, 6;
- their motions in elliptical orbits, mean distance from the sun, 8;
- mode of obtaining the place of, in their orbits, 9;
- computations giving the place of, in space, 10;
- disturbances from reciprocal attraction affecting, compensations, 13-19;
- telescopic, 20, 21;
- perturbations in the mean motions of, 25, 26;
- influence of, on lunar motions, 36;
- eclipses and conjunctions of, 42;
- formula finding their masses, 55;
- their diameters, 56;
- mass of the telescopic, compared with the moon, ib.;
- comparative density, 58;
- method of computing their places, 58-64;
- discovery of, 61-63;
- exploded theory touching telescopic, 63;
- periods of their rotations, 66;
- variation and position of the plane of the ecliptic produced by, 79;
- its effect on the equinoctial points, 80;
- climates of, 225, 226;
- probably magnets, 346;
- constant velocity of their mean motions, 366.
- Plants, distribution of known species over the globe, 249, 250.
- Plates, vibrating, experiments by means of, 144-146.
- Plateau, M., experiments of, on colour, 165, 166.
- Platina, incandescent, used as a source of heat, 260.
- Platinum, experiment producing spontaneous combustion of, 112, 113.
- Playfair, Professor, quoted in reference to La Grange’s discovery, 23.
- Pleiades, the, nebulous stars, 415.
- Plücker, Professor, discoveries of, in the action of magnetism in crystals, 349.
- Plumb-line, deviations of, from local attraction, 48;
- earth’s density calculated from a deviation of, 58.
- Poinsot, M., La Place’s discovery extended by, 23;
- Point, ready escape of electricity from a, 288.
- Poisson, M., decisions of, on the phenomena of capillary attraction, 114.
- Polar basin, probable temperature of, 245, 246.
- —— star, change of position in the, 81, 82.
- —— vegetation, contrasted with tropical, 248.
- Polarity, produced by electricity, 282;
- of magnets defined, 336;
- induced in iron, 337;
- its antithetical manifestations of, 339;
- invariably dual, 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, 81.
- Pressure, electricity elicited by, 283, 284;
- Principato Citeriore, earthquake in, 234.
- Prisms, solar spectrum formed by, 159;
- neutralizing effects of colour, 164;
- of brown tourmaline, light polarized by, 180;
- resolution of the pure white sunbeam by, 222;
- substance of, determining the point of maximum heat in the solar spectrum, 263, 264;
- electrical light analysed by, 288.
- Problem determining the motions of translation of the celestial bodies, 11;
- of the three bodies, 58;
- the hardest astronomical, 92.
- Procyon, light of, 402.
- Proportion, definite, the law of, in mixing substances, 111, 112.
- Protoxides of metals, their crystals, 109.
- Prussia, Eastern, fulgorites from, 293.
- Ptolemy, decrease in the inclination of Jupiter’s orbit since the age of, 19;
- discovery of the Evection by, 35;
- Indian lunar tables calculated in his time, 88;
- horoscope ascribed to the age of, 89;
- effects of refraction observed by, 155;
- colour of Sirius in his time, 401.
- Quadratures, the equation of the centre in, 9;
- lunar orbit augmented in, 35;
- tides affected by the moon in, 96.
- Quadrupeds, distribution of distinct species of, 255.
- Quartz, crystallised, light polarized circularly by, 189, 190;
- varieties of polarization exhibited by, 193.
- Quebec, extremes of temperature found in, 247.
- Quinine, sulphate of, producing fluorescence of light, 197.
- Radial force producing periodical changes in relative positions of the heavenly bodies, 15;
- effects produced by, 16, 17;
- principle neutralising its ultimate result, 19, 20.
- Radiation of heat, laws regulating, 257;
- universal from substances, 268;
- natural phenomena resulting from, 269;
- slow decrease of the earth’s central heat from, 232;
- influence of, on temperature, 239;
- power of, in water compared with dry land, 242;
- of heat, a transfer of motion, 277.
- Radii vectores, signification of, 8;
- areas described by, 10;
- force disturbing in the direction of, 14, 15.
- Ragona-Scina, M., his theory of rayless lines in the spectrum, 163.
- Rain, force shaping drops, 106;
- cause of periodic tropical, 123;
- region of, 124;
- theory of its formation, 270;
- an electric conductor, 292.
- Rankine, Mr., his theory of the structure of matter, 104;
- his theory of the absorption of light, 177.
- Rays, common nature and common properties of, 268.
- —— of heat, existing independently of luminous, 257;
- laws of transmission of, 258;
- analogy between transmission of luminous rays and, 259;
- temperature of their source affecting transmission, 260;
- varying in nature with their origin, 261;
- transmitted through coloured glass, 262;
- traversing various media, ib.;
- subject to refraction and reflection, 263;
- polarized, 265-267;
- absorption and reflection of, 268;
- rotation of polarized, caused by magnetism, 319.
- —— of light, bent by passing from rare into dense media, 153;
- partial and total reflection of, 156;
- loss of, by obliquity of incidence, 158;
- theory of their transmission and absorption, 159-161;
- comparative refrangibility of, 163;
- experiments on dispersion of, 164;
- principle determining their colour, 170, 171;
- transmission of, in glass or water, 177, 178;
- conditions of polarized, 179;
- double refraction, 181-183;
- polarized by reflection, 184, 185;
- coloured images produced by interference of, 194, 195;
- internal dispersion of, 195-198;
- heat, light, chemical action, independent properties of, 214, 215;
- undulations constituting, 223;
- conditions modifying the power of solar, to produce heat, 237;
- transmitted independently of calorific rays, 258;
- magnetizing of polarized, 318, 319.
- Rays, solar, effect produced by their refraction in lunar eclipse, 40;
- passing between lunar mountains in solar eclipse, 41.
- —— of the solar spectrum, their chemical properties, 203;
- varying chemical energy, 207, 208;
- varying nature of their action, 208;
- peculiar chemical action of the red, 209-211;
- deoxydating and oxydating action of, 211, 212;
- experiments detailed, 212-215;
- new, obscure, detected by Sir John Herschel, 217.
- Red Sea, the, tide in, 98.
- Reflection of waves of sound, 137, 138;
- of rays at surfaces of strata differing in density, phenomena occasioned by, 156, 157;
- affecting colour, 160;
- motion of a ray of light in, 177;
- light polarized by, 184, 185;
- elliptical polarization produced by, 193;
- heat polarized by, 266;
- of radiant heat from surfaces, 268.
- Refraction of the sun’s rays in lunar eclipses, 40;
- of waves of sound, 138;
- of light by the atmosphere, 153, 154;
- mode of estimating, in case of celestial bodies, 155;
- formulæ obtaining in case of terrestrial objects, ib.;
- phenomena occasioned by, 155, 156;
- colours decomposed by, 159, 160;
- produced without colour, 164, 165;
- power of, in media affecting the elasticity of the luminous ether, 177;
- of a polarized ray, 180;
- double, 181, 182;
- Fresnel’s theory of, 183;
- diminished capability of producing fluorescence, 196;
- capability of, in rays, affecting their chemical action, 209-212;
- effect of, on the lunar atmosphere, 226;
- influence of, on transmission of heat, 258;
- of rays of heat, 261-264;
- heat polarized by, 266.
- Refrangibility, substances diminishing, of light, 196;
- affecting the chemical action of rays, 209-212;
- affecting radiation of heat, 257;
- affecting transmission of radiant heat, 261-263.
- Reich, Professor, temperature of mines observed by, 228;
- mean increase calculated by, 230.
- Reptiles, distribution of distinct species of, 254.
- Repulsion of electricities, 283;
- experiments determining the laws of electrical, 286, 287;
- modes of, in static and in Voltaic electricity, 317;
- developing comets’ tails, 375-377.
- Resistance, a cause of accelerated motion, 367.
- Retina, the, action of, in receiving impressions, 166;
- comparative sensibility of its fibres to light, 178.
- Retrograde motion of comets, 359, 368, 373, 379.
- Rhodiola rosea, identical species of, found in Tartary and in Scotland, 251.
- Rhombohedrons of carbonate of lime, 109.
- Richman, Professor, killed by lightning, 293.
- Richter, variation in length of the pendulum observed by, 51.
- Rings of Saturn, 66-68;
- Saturn’s, diamagnetic, 347;
- luminous, surrounding comets, 374, 375;
- surrounding Donati’s, 379.
- Ritchie, Professor, electrical experiments of, 314.
- Ritter, M., chemical properties of the solar spectrum observed by, 203;
- oxydizing effect of red rays, 209.
- Rive, M. Auguste de la, rate of increase of temperature in wells observed by, 230.
- Rivers, curvature of the land proved by, 46;
- influence of, on the earth’s rotation, 71;
- rising of tides in, 98;
- effect of, in cooling the atmosphere, 243.
- Roget, Dr., phenomena of electro-magnetism explained by, 313.
- Rome, observations on lunar mountains made at, 70;
- era fixed at, 85;
- comet discovered from, 370.
- Ross, Sir James, stratum in the ocean discovered by, 101;
- depressure of the barometer observed by, 120;
- volcanic region discovered, 232.
- Rosse, Lord, nebulæ resolved by his telescope, 407, 408;
- spiral nebula, 409, 410;
- annular nebulæ discovered by, 410;
- nebulous star, 411;
- planetary nebulæ, 412;
- nebulæ resolved by, 415.
- Rotation affecting winds, 122-127;
- of winds, 124, 125;
- of hurricanes, 125, 126;
- produced by the Voltaic current acting on iron, 305;
- of stratifications of electrical light, 307;
- caused by electricity, 313, 314;
- of light caused by an electric current, 319;
- of magnets producing electricity, 330-332;
- changes produced in comets by, 376.
- Rotations of the solar system, 7;
- of the sun, 65;
- of the planets, 66;
- of satellites, 68;
- of Jupiter’s satellites, 70;
- of the earth, a measure of time, 71;
- influence of temperature on, 72;
- axis of, invariable, 76, 77.
- Rotatory motion, form indicating, 65;
- Roux, M. le, observations on magnetic action in crystals, 350.
- Rudberg, M., refrangibility of substances ascertained by, 201, 202.
- Ruhmkorff, M., improvements on his electro-inductive apparatus, 328.
- Russell, Scott, Mr., velocity of the tidal wave estimated by, 95.
- Russia, arc of the meridian measured in, 48;
- Sabine, General, variations in the magnetic elements investigated by, 343, 344.
- Sagittarius, comet traversing the constellation of, 379;
- the Milky Way in, 386;
- nebula, 414.
- Sahara, the, causing monsoons, 124.
- —— desert, extent, influence of, on the atmosphere, 243.
- Salt, Mr., papyrus sent from Egypt by, 89.
- Sand, tubes in, formed by lightning, 293.
- Sandy deserts influencing temperature, 243.
- Sandwich Land, excess of cold in, over corresponding latitudes, 241.
- Sargassa, or grassy sea, found in the Atlantic, 253.
- Satellites, intensified action of attraction upon, 7;
- intimate union of, with their primaries, 26;
- exceptions to a general law of the solar system, 65, note;
- rotations equal to the times of their revolutions, 68;
- comet passing through, 69.
- ——, Jupiter’s, proportion of their mass to that of their primary, 27;
- disturbing force of attraction affecting their orbits, 28;
- periodic and secular inequalities, 28, 29;
- eclipses, 30;
- rotation, 70;
- passage of a comet through, 359;
- comet nearly approaching, 370.
- —— of Saturn, 32;
- of Uranus and Neptune, 33.
- ——, mode of computing their masses, 55;
- comparative density of, 58.
- —— of Neptune, 63.
- —— of the earth, shooting stars, 423.
- Saturn, unequally occurring compensations of disturbance in its motions, 15;
- disturbing influence of, on Jupiter, excentricity of its orbit compared with Jupiter’s, 17;
- retarding the revolution of Jupiter’s nodes, 19;
- invariable plane passing between Jupiter and, 24;
- observations on the mean motions of Jupiter and, 25, 26;
- eclipse of, 42;
- internal structure, 58;
- astronomical tables of, 60;
- period of his year, 66;
- the rings of, described, 66-68;
- his ring probably diamagnetic, 347;
- action of, on Halley’s comet, 362, 363;
- comets having their perihelia in his orbit, 381.
- Saurian reptiles, distinct tribes of, 254.
- Saussure, M., temperature of mines observed by, 228, 229;
- lichen discovered by, 249.
- Savart, M., his researches and experiments in acoustics, 132, 133;
- experiments on vibrations of glass rulers, 145-147;
- experiments showing sympathetic undulations, 148, 149;
- discoveries on the nature of voice, 152.
- Savary, M., orbital elements of a double star determined by, 396;
- his mode of ascertaining the actual distances of fixed stars, 402, 403.
- Scheele, M., chemical changes effected by the solar spectrum observed by, 203.
- Schroëter, height of planetary atmospheres calculated by, 226.
- Schwabe, M., periodic variation in the solar spots observed by, 344.
- Science, its value regarded as the pursuit of truth, 1;
- errors of the senses corrected by, 32;
- evidence of its antiquity, 87.
- Sciences, mutual relations of forces proving the connexion between, 319-321;
- analysis proving the whole circle of, kin, 427, 428.
- Scoresby, Captain, phenomenon occasioned by refraction observed by, 156.
- Scorpio, vacant patch of the Milky Way in, 386;
- position of, 390;
- a double star in, 395;
- nebula in, 414.
- Scotland, progress of the tidal wave round, 94.
- Sea, the, inappreciable influence of, on the direction of gravity, 77;
- mean height of snow-line above the level of, 241;
- comparative extent of, 242.
- Seasons, conditions determining the duration of, 74;
- cause of their unequal periods, 87;
- theory of the tropical dry and rainy, 123.
- Seaweeds, photographic impressions of, 205, 206;
- luxuriance, deep colours of, 253.
- Secchi, Professor, mountains of the moon observed by, 70;
- photographic image of the moon obtained, 214;
- temperatures of the sun’s surface estimated, 225;
- experiments of, in photographing the moon and Jupiter, 226, 227.
- Secular inequalities of planets, 13, 14;
- means of discovering, 24, 25;
- effect of, on the mean motion of the moon, 36, 37.
- —— variations in mean values of the magnetic elements, 343.
- Seebeck, point of maximum heat in solar spectrum fixed by, 263;
- discovery of, 264;
- relations of heat to electricity discovered by, 332, 333.
- Seed-lobes, proportion in the distribution of plants having one or two, 252.
- Seleniate of zinc, crystals of, 107.
- Senarmont, M., experiments of, in expansion of crystals, 273.
- Senses, necessarily inaccurate testimony of the, 281.
- September, times coinciding in, 84.
- Serpentarius, star in, vanishing, 392.
- Shell-fish, their mode of clinging to rocks, 117.
- Shield, the, clusters of the Milky Way between Ophiuchus and, 387.
- Shooting stars, phenomena of, described, 421, 422;
- Siberia, Eastern, depression of the barometer observed in, 120.
- Sidereal times, mean, periods of, 83;
- measurement of apparent, ib.
- Sigma Eridani, period of revolution in, 400.
- Silesia, fulgorites from, 293.
- Silver iodized, its sensitiveness to impressions, 221.
- Sirius, the Egyptian year estimated from, 85;
- comet’s tail extending from the Hare to, 373;
- rank of, 384;
- comparative magnitude, 385;
- parallax, 389;
- cause of his irregular motion, 392;
- change in colour, 401;
- light, 402;
- extent of surface, 404.
- Smyth, Admiral, his measurement of Etna compared with Sir John Herschel’s, 120;
- eclipse of a double star observed by, 397;
- its periodic time determined, 398.
- ——, Piazzi, heat of the moon felt by, 227.
- Snow, cause of perpetual, on summits of alpine chains, 119;
- causes modifying the height of the line of perpetual, 241;
- protecting vegetation, 249;
- radiation of heat by, 257.
- Soda, sulphate of, change of form in its crystals, 107;
- crystals of the neutral phosphate and the arseniate of, 109.
- Soil, the, dependence of temperature on the nature of its products, 243.
- Solar gravitation, 424, 425.
- —— magnetism, its connexion with terrestrial, 344.
- —— spectrum, cause of the point of maximum heat varying in, 263, 264.
- —— system, the, gravitation of the bodies composing, 5;
- conditions securing the stability of, 11, 12;
- proof of its stability, 20;
- equilibrium of, underanged by the ethereal medium, 22;
- invariable plane, forming the equator of, 23, 24;
- question of its revolution round a common centre, 24;
- properties of its medium, 32;
- masses of bodies composing, 55, 56;
- their diameters, 56;
- uniform direction of rotation in, 65;
- comparative apparent importance of, in creation, 226;
- probably magnetic throughout, 346;
- comets forming part of, 365;
- possible ultimate destruction of, 372;
- computations of comets revolving within, 381, 382;
- paths described by heavenly bodies in, 382, 383;
- position of, relative to the Milky Way, 385;
- direction of its motion, 405.
- Soleil, M., crystals compressed by, 189.
- Solids, conditions reducing molecular particles to, 104, 105;
- distinctive forms taken by matter in, 106;
- velocity of sound passing through, 135;
- change of shape in, accompanying ringing sound, 147;
- expansion of, by heat, 271.
- Solstices, the, solar motion at, affecting the duration of time, 84;
- the year estimated from the winter, 85;
- periodical coincidence of the solar perigee and apogee with, 86, 87.
- Sothaic period, the, of the Egyptians, 85.
- Sound, medium conveying, 129;
- its propagation by undulations illustrated, 129, 130;
- conditions modifying the intensity of, musical notes, 131;
- experiments testing the compass of audible, 132, 133;
- media modifying the velocity of, 133-137;
- laws of its reflection from surfaces, 137, 138;
- undulations of, subject to the laws of interference, 138, 139;
- laws of the foundation of musical science, 140-143;
- reinforced by resonance of cavities, 150, 151;
- repeated vibrations required to produce, 178;
- different modes of action in undulations producing light and, 199, 200;
- identical nature of heat and, 280, 281;
- measuring velocity, 290, 291.
- Sounding boards, intensifying musical vibrations, 149;
- action of, in musical instruments, 150.
- South, Sir James, positions of stellar systems measured by, 396.
- South pole, the, excess of cold at, 241.
- —— Sea islands, height of tides at, 98.
- Southern Ocean, rise of the tidal wave in, 93;
- velocity of the wave, 94.
- Spain, meteoric showers off the coast of, 421.
- Specific heat defined, 275.
- Spectra of gases and flames, their characteristic peculiarities, 163, 164;
- three superposed, of the pure white sunbeam, 222.
- Spectrum, the solar, decomposed into seven colours, 159;
- colours of, modified by thickness of the medium absorbing, 160;
- decomposed into three colours, 161;
- rayless lines in, 162;
- observations and experiments on rayless lines, 163, 164;
- experiment of fluorescent light, 197;
- obtained independently of prismatic refraction, 201;
- energetic action of, on matter, 203;
- photographic coloured images of, 208-210;
- analysis, properties of, experiments, 211-219;
- complex nature of, 222;
- produced from diffracted light, 223.
- —— of an electric spark, 289.
- —— of the Voltaic arc, 303.
- Spheres, mode of attraction in hollow and solid, 4;
- planets partaking the nature of, 7;
- impulses regulating rotations, ib.;
- conditions procuring the figure of, 44;
- formula finding the density, 56;
- force giving the form of, 106;
- power of retaining electricity, 288.
- Spherical form, the result of cohesion, 106.
- Spheroids, influencing attraction differently from spheres, 4;
- force disturbing attraction in, 27;
- compression of the terrestrial and of Jupiter’s, computed, 38, 39;
- of elliptical strata, quantities invariable in, 46;
- of the sun, 65;
- effect produced by the attraction of an external body on, 79;
- power of retaining electricity, 288.
- Spiral nebula, 409, 410.
- Spots on the sun’s surface, periods of their vicissitudes, 224;
- amount of heat varying with, 225.
- Spring tides, 96-99.
- Springs, hot, rising in mines, 229;
- mean heat of the earth determined from, 238.
- Standards of weights and measures, whence derived, 89, 90.
- Stars, fixed, the, the solar system probably not independent of, 24;
- velocity of light deduced from aberration of, 31;
- vast distances of, 54;
- precession affecting their longitudes, 80;
- computations of their positions furnishing historical data, 88, 89;
- made visible by refraction, 154;
- peculiar law of light demonstrated by the aberration of, 202;
- magnitude of the solar system seen from, 226;
- numbers, classification of, 384;
- positions, 385;
- the Milky Way, 385-387;
- parallaxes and distances of, 387-389;
- variable, 390-395;
- missing, 395;
- systems of multiple, classified, ib.;
- binary, 395-406 (see Double stars);
- nebulous, 406-419 (see Nebulæ);
- seemingly innumerable, 420;
- meteors, 420-423.
- Static electricity, 282:
- Steam, formation of, 269;
- force converting liquids into, 277;
- measure of its elasticity, 278;
- question of its being superseded by electricity, 328.
- Steel, paramagnetism induced in, 336;
- conditions of magnetic power remaining permanently in, 337, 338;
- its elasticity affected by magnetism, 352.
- Stephenson, George, quotation from, 279-280.
- Stokes, Professor, remarks of, on gradation of colours, 161;
- experiments on fluorescence of light, 197;
- his decision with regard to vibrations of polarised light, 223.
- Storms, magnetic, 344;
- varying with latitude, 345, 346.
- Strata of the earth, position and comparative density of, 77.
- Stratifications, experiments showing, in electric light, 306, 307.
- Struve, M., measurement by, 48;
- his observations on Saturn’s rings, 68;
- occultation by a comet observed by, 364;
- comet’s nucleus described, ib.;
- distance of a fixed star measured by, 388, 389;
- catalogue of double stars, 396;
- remarks on colour and light of double stars, 401;
- sun’s motion proved by, 405.
- Stutgardt, natural hot springs used in manufactories near, 231.
- Submarine telegraph, 325-327.
- Sulphate of magnesia, its crystals boiled in alcohol, 108.
- —— of nickel, effect of exposure to the sun, on its crystals, 107.
- —— of soda, its crystals, 107.
- —— of zinc, experiment on its crystals, 108.
- Sulphuretted hydrogen gas, its constituent parts, 111.
- Sumbawa, volcanic eruption of, 233.
- Summer, mean temperature of, varying in the same latitude, 246, 247;
- atmospheric electricity in, 291.
- Sun, the, law regulating his attraction of heavenly bodies, 5;
- effect of his attraction on planetary orbits, mean distance of planets from, 8;
- importance of his magnitude in the solar system, 12;
- disturbances in the relative positions of planets and, 14;
- force modifying his intensity of attraction, 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, 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 cultivation of wheat observed by, 250.
- Sympathetic vibrations in musical instruments, 147-149.
- Syren, the, an instrument ascertaining the number of musical pulsations in a second, 143.
- Syzygies, tides increased in the, 96.
- Table-lands, high, influence of, on the atmosphere, 241.
- Tahiti, transit of Venus observed at, 53.
- 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 photography, 204.
- Tangent, a, to planetary orbits, planets impelled in the direction of, 8;
- force, disturbing, in the direction of, 14, 15;
- deflection from, a measurement 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 constellation of, 379;
- Temperature, a decrease in, affecting the earth’s rotation, 72;
- excentricity of the terrestrial orbit, a cause of decreasing, 73;
- law equalising, 74;
- geological changes affecting, 75.
- ——, varying in the terrestrial atmosphere, 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;
- underground stratum of constant, 228;
- rate of increase in, below the earth’s crust, 228, 231;
- of the ocean, 231;
- mode of finding annual average, 239;
- causes of disturbance in regular variation of, 240-245;
- variations in the same latitude, 246, 247;
- influence of, on vegetation, 248;
- affecting transmission of heat, 259, 260;
- of solid bodies, caused by absorption of rays, 268;
- affecting the length of the pendulum, 272;
- causes of perpetual variations in, 274;
- transmission of electricity affected by, 284;
- affecting 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 variation, 344;
- its connexion with solar magnetism, ib.;
- effect of atmospheric magnetism on, 345;
- probable 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 measuring heat, 333, 334.
- Thermography, examples of, 219-221.
- Thermometer, the, principles applied to the construction of, 113;
- consulted in determining mountain heights, 119, 120;
- refraction varying with, 154;
- heat measured by motion in, 274.
- Thermomultiplier, use of, in experiments, 264;
- principle of its construction, 333, 334.
- Theta Orionis, the multiple system of, 395.
- Thomas, St., the island of, hurricane with pauses at, 127.
- Thomson, W., Professor, experiments of, in freezing water, 271;
- dynamical 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 medium computed by, 356;
- magnetic property of the ethereal medium pleaded for, 357.
- Thunder, theory of prolonged peals of, 138.
- Tibet, wheat ripening in, 250.
- Tidal wave, theory of, 92;
- its birthplace, 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;
- rising, progress of, 93, 94;
- three kinds of oscillations in, 95, 96;
- variations in, from lunar and solar influence, 96-98;
- effect of interference of waves on, 99;
- the sea’s equilibrium underanged by, 100.
- ——, lunar and diurnal, of the terrestrial atmosphere, 121;
- examples of sympathetic undulation, 148.
- Time, a measure of motion, 58;
- a measure of angular motion, 83;
- difference between mean and apparent 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 observations with Hipparchus, 80.
- Tomboro, submerged in a volcanic eruption, 233.
- Toronto, observations on magnetic storms at, 346.
- Torpedo, the, electrical action of, 310, 311.
- Torricellian vacuum, experiment on the electric discharge in the, 306;
- lines of magnetic force passing through, 344.
- Toucan, comet approaching the constellation of, 379;
- Toucani, 47;
- globular nebulous cluster, 414.
- Tourmaline, brown, light polarized by prisms of, 180;
- property qualifying it to analyze polarized light, 182;
- coloured images produced by, 186, 187;
- changed by compression, 189;
- heat polarized by, 265;
- electricity 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 atmospheric anomalies, 120;
- theory of their origin, phenomena connected 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;
- probable 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 revolution 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, 248.
- Tuileries, clock in the, showing decimal time, 84.
- 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;
- intervals produced by interference, 139;
- giving musical notes, 142, 143;
- sympathetic, 147, 149;
- of the luminous ether, 169, 170;
- in refraction and reflection, 177;
- producing fluorescence, 197;
- different, in light and sound, 199, 200;
- constituting a sunbeam, 223;
- heat propagated by, 267;
- of light, evolution of latent force in extinguished, 279, 280;
- of natural forces identical, 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 motion proving, 367.
- —— theory, experiments determining in favour of, 200, 201;
- final and decisive experiment, 202;
- of heat, 267.
- Unison, note in, 142.
- United States, astronomical observations 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;
- discovery suggested by his perturbations, 61;
- observations on, leading to Neptune’s discovery, 62;
- sun’s influence in, 225;
- action of, on Halley’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;
- 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;
- Variable stars, periodic fluctuation of lustre in, 390, 391;
- new, appearing and vanishing, 392, 394;
- missing, 395.
- Variables, region of the, 122.
- Vegetation, effect of, in lowering temperature, 243;
- the two requisites for, 248;
- strength and vitality of, 249;
- chemical action of light influencing, ib.;
- laws of its distribution, 249-252;
- distribution of marine, 252, 253;
- theories of specific diversity of original distribution of, 253, 254.
- Venus, zone of instability between the sun and, 21;
- perturbation in the mean motion of the earth and, 26;
- eclipsing Mercury, 42;
- transits 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 polarized 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.
- Vietch, James, comet with luminous rings discovered by, 374, 375.
- Vincent, St., revival of an extinct volcano in, 234.
- Virginia, daguerreotyped spectral image obtained in, 213.
- Virgo, planetary conjunction between Libra and, 42;
- variable star in, 392;
- star vanished from, 395;
- nebulous zone passing, 416, 417.
- 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.;
- earthquakes 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 battery, 298, 299;
- theory of its production, 300;
- characteristic properties, 300, 301;
- action of, generating 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;
- crystallization, 308;
- an agent in the fine arts, 309;
- conductors of, ib.;
- relations of heat and, 310;
- fish producing effects of, 310, 311;
- science suggested by its influence on a magnetized needle, 312;
- rotation effected by, 313, 314;
- inducing magnetism, 314, 315;
- distinction between static electricity and, 317;
- unvarying dual force of, 334.
- Voltaic pile, the, invention of, 297;
- 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 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, 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 refraction, 156;
- discovery of rayless lines in the solar spectrum, 162;
- observations of, on the chemical properties of the solar spectrum, 203, 209;
- magnetic rotation suggested 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 adduced by, to a general law in acoustics, 137;
- his theory of the pleasures of harmony, 142;
- undulatory 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.
- Zeta Herculis, periodic time, eclipse of, 398;
- Zinc, seleniate of, effect of temperature on its crystals, 107;
- sulphate of, its crystals boiled in alcohol, 108.
- ——, electricity communicated to plates of, 220.
- Zodiac, the, signs of, change in their positions, 80.
- Zone of constant temperature in the atmosphere, 119;
- laws of storms in the temperate and torrid, 127, 128;
- of spots on the sun’s surface, its breadth, 224;
- of constant temperature below the earth’s crust, 228;
- comparative unequal distribution of land in temperate and torrid, 244;
- of fixed stars, 385;
- of stars nearest the sun, 390;
- nebulous, 416;
- of nebulous patches, 417;
- of meteoric nebulæ, 423.
- Zones of instability of planetary orbits, 21.
- —— of temperature in the ocean, 101.
- —— of vegetation on the Peak of Teneriffe, 250.
- Zoophytes, specific distribution of, 254.