in the solar spectrum discovered, 216; cause of phosphorescence, 217; electricity excited by pres- sure, 283; light attributed to elec- tricity by, 284; cause of phospho- rescence investigated, 296; in- strument comparing intensities of electricities invented, 300; crys- tals formed by agency of electricity, 308; thermo-electric battery con- structed by, 333; effect of atmo- spheric on terrestrial magnetism estimated, 345.
Beehive, the, a nebulous star, 415, Berard, M., experiments of, in polar- izing heat, 264.
Berlin, line of coincidence in tempe- rature passing through, 238. Berne, increasing temperature of a deserted mine in, 230. Berre, Dr., photographic pictures per- fected by, 205.
Bessel, M., his calculations from mea- surements of arcs of the meridian, 48; calculation of the sun's mean apparent diameter, 56; his compu- tation 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,
Beta Lyræ, a variable star, 391; ne- bula between y Lyræ and, 410. Bezenberg, M., velocities of falling stars computed by, 423. Biela, M., date of the discovery of his comet, 367; possibility of col- lision with the earth, 368; present and prospective planetary influence on, 369; becoming two distinct bodies, 369, 370.
Binary systems of stars, 395-406. See Double stars.
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 polar-
ization, 191; cause of phospho- rescence in the solar spectrum inves- tigated by, 217.
Birds, distribution of distinct species of, 255.
Birt, Mr., atmospheric waves mea- sured 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 com- puting Neptune's position, 61; failing in the case of Neptune, 63. Bond, Mr., satellite of Saturn dis- covered 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.
Böotes, nebulous system in, 417. Bore, the, of the Hooghly, its origin,
Botanical districts, distinct, of the globe, 251, 252.
Botto, M., thermo-electricity used in decomposition by, 333.
Bouguer, degrees of the meridian mea- sured by, 48.
Boussingault, M., depth of the under- ground 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 me- teors, 423.
Brewster, Sir David, his analysis of the solar spectrum, 161; experi- ments on rayless lines, 163; ex- periments on spectra of flames, 164; law discovered by, deter- mining angles of polarization for light, 183; experiments on fluor- escence of light, 197; line of coin-
CESAR, 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. See Rays of heat. 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,
Capillarity, theory of, 113; forces
producing, 114; familiar examples of, 115; curious phenomena, 115,
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. See Lime. Carbonic oxide, its constituent parts, 111.
acid, proportion of, in the atmo- sphere, 117.
Cardinal points, the, position of con- tinental masses with regard to, in- fluencing temperature, 244. Caribbean Islands, hurricanes begin- ning at, 126.
Castor, discovered by Sir William Herschel, 396.
Cassiopeia, star appearing and vanish- ing in, 392, 393.
Categat, the, consequence of its nar- rowness, 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 dis- turbance in their motions through counteracting attractions, 11; theory of their mutual connection and dependence, 24; mode of find- ing 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. See Gravity. Centrifugal force, moon's motions
modified by, 5; influence of, on planet-forms, 6; retarding oscilla- tions 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 rovolving 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 electri- city from, 302-303. Charles V., the Emperor, observa- tions on comets, made in his reign, 370.
Chaudes Aigues, temperature of, 231. Chemical action of rays of the solar spectrum, 203, 207; varying maxi- mum of energy, 208; action vary- ing with refrangibility, 209-212; action in luminous spectrum not continuous, 213; energy an inde- pendent 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 elec- tricity on oxygen, 284; eliciting voltaic electricity, 297, 300; vol- taic electricity, an agent in, ana- lysis, 307, 308.
combinations, theory of, 110; invariable proportions of, 111; co- hesive force inducing, 112; pro- ducing combustion, 270.
force, the power of, 112.
rays, causing the deposition of dew, 269.
Chile, elevation of land by an earth- quake in, 234.
China, distinct flora of, 251.
Sea, the, monsoons 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 ob- servation, 365; comet of 1264 recorded by, 370.
Tartary, herbarium collected in, 250, 251.
Chladni, discovery of, in musical sci- ence, 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,
orbits of planets distinguished from elliptical, 8; of satellites, 27. polarization of light, 189-192; of heat, 266.
Circumference of the earth, 49. Civil time, measure of its periods, 83; not precisely adjusted to solar re- volutions, 85.
Clairaut, periodic time of Halley's
comet computed by, 362, 363. Cleavages of crystals, 109; position of, affecting the intensity of mag- netic 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; compensa- tions of irregularities, 247. Clocks, showing apparent sidereal time, 83; regulated to show de- cimal time, 84; irregular action of, corrected by the laws of unequal expansion, 272.
Clouds, circling the belt of equatorial
calms, 123; region of, 124; elec- tricity evolved from, 291-292. Cloyne, Bishop of, his calculation of the moon's mass, 50. 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; ef- fectual only to unite particles of like nature, 110; inducing chemi- cal combination, 112; capillary attraction, an action of, 113. Coins, impressions taken from, by contact, 220; by electricity, 221. Cold, contraction caused by, 271, 272; mitigated by slow propaga- tion of heat in air, 273; generated by voltaic electricity, 302; in- creasing 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 refran- gibility not invariable, 161; three primary, ib.; new, discovered by Sir John Herschel, 162; rays re- fracted without, 164; rarely ho- mogeneous, 165; experiments on accidental and complementary, 165, 166; determined by undulations of ether, experiments, 170-175; of material substances, whence de- rived, 175; produced by analyzing polarized light, 186-188; varying with refrangibility of rays, 198; obtained in photography, 206; images of the solar spectrum imi- tating 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 nébulæ, 412; of nebulous clusters, 415. Columbus, beds of algae 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; defined, 304.
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 sa- tellites, 69; return of, to their perihelia, furnishing historical data, 88; existence of the luminous ether demonstrated by, 168, 169; terres- trial atmosphere unaffected by, 358; amount of their light com- puted, 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; ve- locity, sun's influence on, 371, 372; of 1843, 372, 373; their constitu- tion, 373, 374; of 1811, its lu- minous envelopes, 374, 375; sud- den convulsions in, 375; tails, 375-377; causes assigned for con- traction 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 dis- turbing, 312; intensity of a gal- vanic current measured by, 315.
Compression of the terrestrial sphe- roid, calculations of, 48-51; cause of the great, in Jupiter, 66; mea- sures of, from pressure of super- incumbent mass, 78; effect of, on magnetic action, 351. Concord, a, in music, 142. Conductors of electricity, 284, 285; lightning, 293; molecular struc- ture determining the power of,
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-conduct- ors of, 293; action of an electro- magnet on, 351, 552. Cordier, temperature of mines ob- served 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,
Corona australis, nebula in, 414. Corpuscular theory of light, 167;
phenomena disproving, 171, 175, 176.
Coseguina, volcanic irruption of, 233. Coulomb, instrument measuring elec- trical intensity, invented by, 287. Creation, vastness and magnificence of, 2.
Crimea, cause of the great storm in the, 122.
Cross, Mr., voltaic battery with con-
stant action invented by, 300. Cross, the Southern, vacant patches of the Milky Way near, 386. Crystallization defined, 106; forms
of, their variety affected by tem- perature, 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 com- pression, 189; transmission of rays of heat by, 258; expansion of, by heat, 272, 273; formed by electri- city, 308; action of magnetism in, 349, 350; circumstances determin- ing 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; prov- ing 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, pro- duced 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 pro- duced 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; dia- magnetic, 348.
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