Part 52

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; orbit and mass of, 398, 399; colours, 401; mass, 404; proper motion, 405.

Cygnus, portion of the Milky Way lying between α Centauri and, 386.

Cylinders, rotating by electricity, 313; electro-dynamic, 316.

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. _See_ Voltaic.

—— 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; effects of light in, 41.

——, 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; construction of, 325-328.

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; on vegetation, 250.

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; of heat, 267.

—— 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; lunar, 35.

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; nebula round, 418, 419.

—— 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; variable star, 390.

Fahrenheit, mode of ascertaining heights proposed by, 120.

Falling stars, 420; theories of, 422, 423.

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; electric, 310.

Fixed stars. _See_ 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; theory of, 276.

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; electricity, 282, 283.

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. _See_ Winds.

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.