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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