ABICH on volcanic phenomena in
Ghilan, 175; his views on the
Caucasian mountain system, 209,
360; analysis of the Chimborazo
rock, 462.

Aconcagua, volcano of, measure-
ment of, 288.

Acosta on the volcancitos of Tur-
baco, 214.

Adams, Mount, a volcano, 417.
Enaria, the island of Apes, 265.
Eolus, residence of, on Strongyle,
257.

Africa, determination of the mag-

netic equator in, by Sabine, 103;
its translation, 106; snowy
mountains in, 354; volcanoes
in, 354; their small number,
355.

African magnetic node, its varying
position, 103.
Agaschagokh, island of, 371.
Agreeable odour diffused from

certain volcanoes, 229.

Agua, Volcan de, described, 276.
Airy, density of the earth deter-
mined by, vii; on terrestrial
magnetism, 79.

Alaid, great eruptions of the vol-
cano on the isle of, 372.
Albite, 469.

Aleutian islands, numerous volca-
noes in, 370.

Alps, temperature of springs in
the, 192.

America. See Central America,

Chili, Mexico, North-west Ame-
rica, Peru and Bolivia, Rocky
Mountains, South Sea.

Ampère on the cause of earth-
quakes, 168.

Ampolletas, 56.

Anahuac, series of volcanoes of,
280.
Anaxagoras, maxim of, verified, 7.
Andaman isles, volcanic pheno-
mena in the, 383.

Andes, large spaces in the chain
of, destitute of volcanoes, 282;
groups and distances, 283; spe-
cial direction of the three Cor-
dilleras, 292.

Andesite, 468, 471.

Andrea Bianco, his early charts,
exhibit the magnetic variation,

54.

Anemasite, 478.

Annular valleys, 231.
Ansango, lake of, 3.

Ansogorri, Father Joaquin, his de-
scription of the rise of the vol-
cano Jorullo, 310.

Ant-hills, in the Rocky Mountains,
their remarkable construction,
475.

Antilles, Little, volcanoes of the,
described, 421.

Antisana, the colossal mountain,
described, 331, its dykes, 331;
lakes, 332.

Antuco, volcano of, 289.
Aphron, the northern pole of the
magnetic needle, 53.
Apparatus employed by Humboldt
for his 453 determinations of
height in the New World, 459.
Arabia, lava eruptions in, 357.
Arago on magnetic inclination,

107; his series of magnetic ob-
servations, vii.

Ararat, as a volcano, 361.
Arare, crater of, 393.
Arequipa, volcano of, 286.
Argæus, the volcano, 249.

385.

Aristotle on the fundamental

principles of nature, 5; volcanic
phenomenon upon Hiera de-
scribed by, 229.

Arran, volcanic phenomena in,
350.

Artesian wells, Walferdin's obser-
vations on, 35.

Ascension, volcanic phenomena of
the island of, 352.
Asia, situation of the principal
volcanoes in, 297; volcanoes of
the western and central parts,
356; of Kamtschatka, 362; of
the islands of Eastern Asia, 367;
of the islands of Southern Asia,
377; of the Indian Ocean, 382.
Atlantic Ocean, volcanoes of the
islands of the, 351; presumed
submarine volcano, 353.
Atlantis of Solon, 179.
Atolls, or lagoon reefs, 388.
Attraction of the magnet known

to the Greeks and Romans, 50.
Augite, 475.

Aurora borealis, 152; observa-
tions of the black segment, 152;
colours observed in high lati-
tudes, 154; accompanying flee-
cy clouds, 155; influence on
terrestrial magnetism, 157; ob-
servations at Berlin and at Edin-
burgh, 158.

Auvergne, extinct volcanoes of,
238, 278.

Azores, craters of elevation in the,

227; the volcano Pico, 247.
Azufral de Quindiu, Humboldt's
visit to the, 221; change of tem-
perature observed by Boussin-
gault, 221.

Baily on the density of the earth,
31, 32.

Baker, Mount, a volcano, 418.
Banda, a volcanic island, 381.
Barba, the volcano, described,
273.

Barile, earthquake at, 173.
Barraucos on the slopes of vol-
canoes, 304.

Barren Island, one of the Anda-
mans, appearance of, as de-
scribed by Horsburgh, 383.
Basalt-like columns of Pisoje, 456.
Beaufort, Admiral, the Chimera
described by, 257.

Beauvais, Vincent of, on the mag-
netic needle, 53.

Belcher, Sir E., magnetic observa-
tions by, 113.

Bell-shaped volcanic mountains,
228.

Berg, Albert, his description of
the burning spring, Chimæra,
257.

Berlin, aurora observed at, by
Humboldt, 158.

Bessel, determination of the size
and figure of the earth, 14, 27.
Biot, pendulum measurements by,
23.
Bolivia.

See Peru.

Borda, his services in equipping
the expedition of La Perouse,

61.

Borneo, the Giava Maggiore of
Marco Polo, 379; doubtful
whether volcanoes exist there
379; great number of volcanoes
in its vicinity, 379.
Bo-shan, eruption of the volcano,
437.

Bouguer's experiments on the de-
viation of the plummet, 30; on
the pumice-quarries of Lactu-
cunga, 342.
Bourbon, volcanoes of the isle of,
383.
Boussingault's method of deter-
mining the mean temperature,
40; on the cause of earthquakes,
170; on the matters ejected from
volcanoes, 335; on gases, 442.
Bove, Val del, on Etna, 225, 241.
Bramidos de Guanaxuato, 178.
Bravais on Artesian wells, 37; on
the black segment of the Au-
rora, 153.
Brisbane, Sir Thomas, his observa-
tory at Makerstoun, 123, 124.

in the, 350, 483.

Bromo, a volcano in Java, its

crater lake, 302.
Brooke, Rajah, on the volcanic
appearances in Borneo, 380.
Brooks of cold water said to be
converted into thermal springs,
314.

Brown, Mount, a volcano, 418.
Buch, Leopold von, his work on
basaltic islands and craters of
elevation, 226; on the erupted
matters of Vesuvius, 235; on
the trachytes of Etna, 469.
Buddhist fancy as to the cause of
earthquakes, 177.

Bunsen on fumaroles, 424.

Burkart, his visit to Jorullo, 318.

Calabria, earthquake in, in 1783,
172.

Calamatico, el, an ancient name for
the magnetic pole, 56.
Calbuco, Volcan de, 290.
California, list of the volcanoes of,
417.

Callaqui, volcano of, 290.
Canary Islands, eruptions in the,
477.

Capac-Urcu,an extinct volcano, 282.
Cape of Good Hope, magnetic
observations at, 113.
Carbonic acid gas, considerations
on, 442.

Carbonic acid gas, jets of, 201.
Cascade Mountain range, in Cali -
fornia, 416.

Castillo, Fray Blas del, explores
the crater of Masaya, 260.
Catalans, advanced state of navi-
gation among the, 53, 54.
Caucasus, volcanic phenomena of
the, 208; a continuation of
the Thian-schan, 360; its ex-
tinct volcanoes, 360.
Cauldron-like depressions of volca-
noes, 231.

Cavanilles, his account of the
earthquake of Riobamba, 173.

Central America, linear volcanoes

of, 268, 272; number of volca-
noes in, 273; recommended for
further examination, 278.
Chacani or Charcani, volcano of,
286.

Chahorra, the crater of, on the

Peak of Teneriffe, 262.
Chatham Island, its position, 401.
Chili, group of volcanoes in, 288;
their greatest elevation, where
attained, 296.

Chillan, Volcan de, 289.
Chiloe, submarine volcano near,
288.

Chimborazo, majestic dome, form
of, 2; ascent of, 464; conside-
rations on the height of the
mountain, 464.

Chimborazo rock, Rammelsberg's
analysis of, 461; Abich's, 462;
remarks on the differences be-
tween them, 463.

Chimæra, in Lycia, not a volcano,
but a perpetual burning spring,
212, 257; analogous phenomenon
in the Kuen-lun, 438.
Chiñal, volcano of, 290.
Chinese, early acquainted with
the polarity of the magnet, 50;
rope-boring, 219; early maps
of the, 434.

Chuapri, volcano of, 288.
Cinders, cones of, wanting in seve-
ral volcanoes which once emit-
ted lava-streams, 481; thickness
of the layers of, on Sangay, 265.
Circumvallations, volcanic, 230;
that of Oisans, in France, its
great extent, 231; of Mont
Blanc, 231.

Columbus determines astronomi-
cally a line of no variation, 54;
notice of an eruption on Tene-
riffe, by, 477.
Comangillas, Aguas de, a hot
spring, 197.

Commotion, waves of, in earth-
quakes, 171; theory of, 172;
attempt to explain the rotatory
shocks experienced in Calabria,
172.

Commotions of the earth in earth-

qnakes often confined within
narrow limits, 182.

Comoro islands, burning volcano
in the, 384.

Compass. See Mariner's Compass.
Compression, polar, 29.
Conchagua, a volcano, 275.
Conical volcanic mountains, 239.
Conseguina, eruption of, 274.
Copiapo, destruction of the town
of, 288.

Coquimbo, volcano of, 288.

Coral islands, number of, in the
Pacific, according to Dana, 390.
Corcovado, Volcan de, 290.
Cordilleras. See Andes.
Corea, volcanoes of, 376.
Cosima, small elevation of the
volcano of, 245.

Costa, Col. A., his experiments on
mean annual temperature, 41.
Cotopaxi, mineralogical composi-
tion of, 343.

Craters of elevation, 226; distin-
guished from true volcanoes,
227. See also Volcanoes.
Crozet's group, traces of former
volcanic action in, 387.
Crust of the earth, considerations
on its varying thickness, 439.
Crystallized minerals of the Maars,
234; greater number found on
Vesuvius, 235.

Cueva de Antisana, 332.
Cyclades, volcanic phenomena in
the, 267.

Dana, James, his valuable re-

searches in the Pacific, 388;
his grouping of the basaltic and
coral islands, 390; on the vol-
canoes of the Sandwich Islands,
392.

Darwin, Charles, his enlarged
views on earthquakes and erup-
tions of volcanoes, 288; general
acknowledgment of obligations
of science to, 389.

Dasar, sand-lakes of, 482
Dechen, H. von, on volcanic phe-
nomena in the Eifel, 236
Declination. See Magnetism.
Degree, table of the increase in
length of the, from the equator
to the pole, 17.

Demavend, volcano of, 356, 357;
question of its altitude, 356.
Density of the earth, experiments
to determine, 30; Airy's results,

vii.

Detritus dykes, 331.
Deville, on the structure and
colour of the mass in certain
volcanoes, 463.
Devonian slate, 231.

Diablo, Monte del, in California,
416.

Diamagnetism, its discovery by
Faraday, 49, 78.

Dio Cassius on the eruptions of
Vesuvius, 427.

Diodorus Siculus on the Phlegræan
fields, 428.

Disturbances, magnetic, table of,
134.

Djebel el Tir, a volcano, 356.
Dome-shaped and bell-shaped
mountains peculiar aspect given
by, to the landscape, 229.
Domite, origin of the term, 450.
Dry fog of the summer of 1783,
421.

Duperrey, his observations on the
magnetic equator, 104.

Earth, its size, configuration and
density, vii, 9; interior heat,
34, 246; magnetic activity, 49;

magnetic storms, 141; polar
light, 151; reaction of the
interior on the surface, 162
(see also Earthquakes, Volcanoes);
thickness of the crust of, pro-
bably very unequal, 169.
Earthquakes, variety of views as
to their cause, 167; the impulse,
167; translatory movements,
173; subterranean noises, 178;
velocity of propagation, 179;
distinguished, but improperly,
as Plutonic and Volcanic, 180;
three groups of phenomena
which indicate the existence of
one general cause, 183; list of
memorable examples of these
phenomena, 183.

Earth-waves in volcanic phe-
nomena, 171.

Eastern Asia, volcanoes of the
islands of, 367.

Edgecombe, Mount, a volcano,
269, 418; another in New
Zealand, 397.

Edinburgh, beautiful aurora ob-
served at, 158.

Edrisi on the land of Gog and
Magog, 359.

Eifel, extinct volcanoes of the,
231; two kinds of volcanic
activity distinguishable, 232;
Mitscherlich on the minerals,
235; Ehrenberg on the infusoria,
237.

Elburuz, as an extinct volcano, 362.
Elevation, question of the in-

fluence of, on magnetic dip and
intensity, 114; craters of, dis-
tinguished from true volcanoes,
227.

Elias, Mount, a volcano, 252, 419.
Elliot, Capt., on the magnetic
equator, 105.

Ellipticity of the earth, specula-
tions of the ancients on the, 26;
Bessel's determination, 27.

El Nuevo, a volcano, 274.
El Viejo, a volcano, measurements
of, 274.

El Volcancito, now a mountain of
ashes, 321.

Emanations from fumaroles, their
nature, 424.

Enceladus. See Typhon.

England, volcanic phenomena in,
350, 483.

Equator, magnetic. See Magnetic
equator.

Erebus, Mount, the volcano, 103,
249.

Erman on the magnetic equator,
105; his researches on the vol-
canoes of Kamtschatka, 363.
Erupted blocks, 479.
Eruption, masses of, considera-

tions on, 225; craters of, 226.
Eruptions of volcanoes, considera-
tions on the general laws of,
255; varying heights to which
matters are cast, 264.

Etna, eruptions of, usually occur
within a space of six years, 255;
periods of its greatest activity,
257; height to which ejected
matters attain, 265; its tra-
chytes, 465.

Euboea, Strabo's description of an
earthquake in, 225.
Europe, active volcanoes of, 349;

extinct volcanoes and volcanic
phenomena, 231, 238, 350, 483.

Faraday's discovery of the para-
magnetic force cf oxygen, 78;
important results expected from
it, 82, 99; on diamagnetism,
49, 78.
Fairweather, Mount, a volcano, 418.
Felspar, variety of minerals com-
prised under the denomination
of, 457, 474.
Ferdinandea, the volcanic island,

349.

Figure of the earth, attempts to
solve the problem, 13; deter-
minations of Bessel, 14; earlier
observations, 16.

Fissures caused by earthquakes,
173; volcanic, 226, 228; vol-