ABERCROMBIE, Hon. Ralph, 655. Adie, J., travelling barometer, 36. Adie, R., conservatory hygrometer, 321. Adie, A., sympiesometer, 44. Abnormal temperatures, 275; caused by ocean-currents, 233. Air-thermometer, invention of, 7. America, influence of its large lakes on the climate, 209, 267. Anemometers, 440. Aneroid barometer, 43. Anthelia, or glories of light, 625. Aqueous vapour as disturbing influence on the atmosphere, 115. Arago on lightning, 589; neutral point of polarisation, 635; on moon's influence on weather, 649. Aristotle' On Meteors,' 4. Athenæum, suggestion by a writer in,

25.

Atmometer, 310.

Atmosphere, drying power of the, 311; height deduced from meteors, 642; from polarisation, 639; mode of measuring the pressure, 50. Atmospheric pressure, distribution over the globe, Chap. III.; its relation to temperature, winds, rain, &c., passim; methods of representing it in storms, 499-501; its irregular distribution in storms, 521.

Aurora borealis, 605; height, 607, relation to terrestrial magnetism, 606, 609; to storms, 611; distribution over the earth, 606.

BABINET'S neutral point of polarisation,

636.

Babington, T. H., 665.

Bacon, Lord, 483.

Baddeley on dust-whirlwinds, 602.

Baker, Sir S. W., inundation of the

Nile, 470; dust-whirlwinds of Nubia, 602.

Balfour, Professor J. H., 539.
Ballingall, R., 655.

Ballot, Dr Buys, 17, 87; LAW OF THE WINDS, 517; apparent exceptions to, 520, 521. 522; 564, 574. Barker, Sir R., 210. Barometer, invention, 6; description of, 27; neutral point of, 34; mode of removing from place to place, and of expelling air from, 37; must be hung perpendicularly, 38; scales, 51; reducing to 32, 47; correction for height, 52; example showing method of reducing, 61; daily variation, 63; do. of dry air, 69; annual variation, 75; corrections for range, their use and abuse, 73, 74; variations, where large, 77; low in storms not the effect of centrifugal force, 565; extraordinary fluctuations in tropical storms, 540; table comparing millimetres with English inches, page 357; and Table III., Paris lines with English inches, page 358.

Barometric gradient, 531, 532. Barometric measurement of heights, 62. Barometric tubes, use of air-trap in, 36. Bates, Rev. J. Chadwick, observations with rain-gauges, 396.

Baxendell, Joseph, 512; on moon's influence on atmospheric temperature,

652.

Becquerel and Breschet's experiments of electricity, 583.

Bennet's electrometer, 580.
Berigny, 615.

Beverley, Rev. A., proportion of rainfall at Aberdeen with different winds, 412.

Black-bulb thermometer (naked), 187, 189, 198.

Black showers, 479.

Blodget's remarks on rainfall of America, 415.

Bohenenberger's electroscope, 581.
Bora, 497.

Borrowing days, 294.

Boussingault, 182.

Brewster, Sir David, on daily march of
temperature, 145; causes which inter-
fere with it, 146, 151; polarisation of
the atmosphere, 637 et seq.
Brewster's neutral point of polarisation,
637.

Bridge of Allan, advantages as a winter
and spring resort, 157.

British Islands, suminer temperature,
273; chart showing, page 121; winter
temperature, 263; where best for in-
valids, 264.
Brough, 622.

Bryce, Dr James, 353.
Buzzard, H. M.S., 570.
Bulletin International, 24.
Burckhardt, 490.

CALMS in storms, 526; region of, 453.
Capacity, error of, in barometer, 34; of
air for vapour in relation to tempera-
ture, 320.

Capillarity in barometer, error of, 33.
Casella's mercurial minimum thermome-
ter, 132.

Caswell, Professor Alexis, 575.

Cavallo's electrometer, 580.

Celsius's thermometer, 121.

Chatfield, Commander, 540, 547, 550.
Chrimes's, R., observations with rain-
gauges, 397.

Cistern barometers, 32.

Climate influenced by great specific
heat of water, 184; influenced by
maximum densities of fresh and salt
water, 207; currents of the sea, 241;
sheets of shallow and deep water
respectively, 267; winds, 268; moun-
tain-ranges, 269; vegetation, 179;
forests, 180, 218, 352; sandy deserts,
178.

Climates, insular and continental, 270;
extreme, their effect on the death-rate,
274.
Clouds, general causes, 358; apparently
resting on hills, cause of, 356; formed
at junction of valleys, 353; classifica-
tion, 369; cirrus, 370; its relation to
storms, and value as a prognostic,
371; cumulus, 375; cause of their
shape, 376; stratus, 378; cirro-cumu-
lus, 380; cirro-stratus, 382; cumulo-
stratus, 385; cumulo-cirro-stratus,
386; pocky cloud, 655; mode of ob-
serving, 389; height, 367; colours;
628; velocity of clouds, 391; relation
to storms, 514, and auroras, 612.
Clouston's, Rev. Dr C., description of
natural snowballs, 425; pocky cloud,
655.

Coffin, Professor J. H., winds of nor-
thern hemisphere, 456, 537.
Cold weather, January and March 1867,
280; Christmas 1860, 286; July 1867,
289; Southern Europe, January 1868,
497. See Temperature and Frosts.
Conduction of heat, 169.
Conservatory hygrometer, 321.

Density of water, maximum, 206.
Dew, history of Theory of, 13; how de-
posited, and where most copiously,
202.

Dew-point of the air, 323; how ascer-
tained, 324, 330; important to horti-
culturists, as predicting frosts, 334.
Diathermancy of the air, 340.
Dové, isothermal lines, 16, 17, 87; ther-
mic isabnormals, 275; annual march
of temperature of the globe, 276; Law
of rotation of the wind, 483, 564; storms
formed by mutual interference of air-
currents, 573, 515.

Drainage as affecting temperature of
soil, 313.

Dry air of atmosphere, daily variation of
pressure of, 69; importance of know-
ledge of distribution of, 682 et seq.
Drying property, its importance as an
element of climate, 311.
Dry-and-wet-bulb hygrometer, 325; pre-
caution in using, 326.

EAST winds of Great Britain, 486; cause
of unhealthiness, 345; as a prognostic,
656, 657.

Education, importance of meteorology as
a branch of, 26.

Elastic force of vapour, 330; represents
the absolute humidity, 336.
Electrcity of the atmosphere, 579;
sources of, 585; in relation to its va-
pour, 586; annual and diurnal periods,
584; great changes during thunder-
storms, 588.

Electrometers, 580.

Electroscopes, 581.

Elliot's, Professor James, experiments
on drainage and temperature of soil,
315, 318.

Ellis, W., on moon influence on cloud,
649.

English Channel, cause of gales there,
528.

Espy on clouds, 363; on charting storms,

501; charts of American storms, 538.
Etesian winds, 497.
Evapometer, 309.

Evaporation, 308; heat lost by, 312;
temperature of, 329; as affecting
sandy, peaty, and heavy soils, 315,

317.
Everett's, Professor J. D., observations
on complete saturation of the air, 319;
underground temperature at Green-
wich, 255.

Explosions in mines in relation to the
barometer, 526.

Extreme temperatures, their value,
158.

FAHRENHEIT's thermometer, 8, 120.
Farquharson, Rev. J., 353.

Fitzroy's, Admiral, storm-warnings, 23,
665 et seq.; temperature of the sea,
228; barometer, 41.

Fleming's rain-gauge, 395.

Fogs of radiation, 347; where most pre-
valent, 355; locally distributed, 351;
on the coast, 354; accompanying
storms, their importance meteorologi-
cally, 357.

Forbes, Principal, on underground tem-
perature, 17, 254, 256; on an interrup-
tion of temperature, 299; on colours
of clouds, 631.

Forests, retardation of their daily maxi-
mum and minimum temperatures,

with the effect on climate, 180; as
affecting mists and rain, 180, 352; on
winter temperature, 218.

Fortin's barometer, 35.

Fournet's Rainfall of France, 19.
Franklin's experiment on atmospheric
electricity, 579; suggests lightning-
conductors, 594; theories for decrease
of rainfall with the height, 398.
Frost, frequency of occurrence as an
element of climate, 166; degree in
which it penetrates into different
soils, 170; may be predicted by the
hygrometer, 335.
Fulgurites, 592.

GALTON, Francis, anti-cyclones, 475; on

small barometric disturbances, 521.
Gases, law of independent pressure, how
modified in the atmosphere, 307.
Glaisher, 17; barometric range for
Greenwich, 72; corrections for heat
and rain temperatures to reduce
to mean temperature, 152; experi-
ments on terrestrial radiation, 196,
199; on long and short grass, 200;
temperature at different heights dur
ing, 212; hygrometric tables, 331;
balloon ascents in relation to humidity
of atmosphere, 336; to currents of

atmosphere, 360; description of
clouds, '366; snow-crystals, 417; on
directions of wind in relation to
moon's changes, 651, 652.

Gulf Stream, temperature of, 233; its
influence on climate of Great Britain,
233, 262.

Guyot's Meteorological and Physical
tables, 60, 88.

HADLEY propounds theory of trade-
winds, 11.

Hail, 432; where most common, 469.
Hailstones, different forms, 433.
Hailstones of Orkney, 28th July 1818,

596, 599; of France, 596, 598; of Câte-
let, 7th May 1865, 597.

Halos, 626.

Hansteen, 17; on auroras, 605, 609.
Harmattan, 494; probable cause, 569.
Harrison, Park, on moon's influence on
clouds and temperature, 650, 652.
Hartnup, John, on velocity of the wind
at Liverpool, 1st February 1868, 530.
Heights measured by thermometer,
119; measured by barometer, 62.
Hemispherical-cup anemometer, 440.
Henley's quadrant electrometer, 580.
Henry, Joseph, 564.

Hermetic barometer, 45.

Herschel, Alexander, on meteors, 641.
Herschel, Sir J., observation on effect
of forests on rain, 352; on rotation of
wind in storms, 549, 564; on atmos-
pheric electricity, 586; on an oak-tree
struck by lightning, 592; on height of
aurora, 607; on temperature of stellar
spaces, 642; on moon's influence, 649.
Hicks's maximum and minimum ther-
mometer, 133.

Hoar-frost, 202; crystals of, 418.
Home, D. Milne, experiments on drain-
age, 316.
Houzeau, 615.

Howard's nomenclature of clouds, 369.
Howson's barometer, 42.

Humboldt's isothermal lines, 16; re-

mark on horary oscillation of barome-
ter in tropics, 63; current, tempera-
ture of, 234.

Humidity, absolute, how distributed,
336; relative, of the air, how calcu
lated, 332; low, observed at Djeddah,
338; Corrimony, 337.
Hurricane of Calcutta, 5th October 1864,
541; of Guadaloupe, 6th September
1865, 540; West Indian, of 1st October
1866, 540; barometric fluctuations,
540, 541; wave of sea accompanying,
541.

Hurricane, moisture of air, 513; track
of centre, see Plate VIII.; rate of its
progressive motion, 546; direction of
wind, 543; veering of wind, 548; ba-
rometer and winds at St Croix, and
H.M.S. Buzzard, 570.

Hurricanes, West Indian, time of occur-
rence, 551.

Hydrometer, 245.

Hygrometers, invention of, 9; of ab-
sorption, 321; condensation, 324;
evaporation, 325.

Hygrometry of the atmosphere, 319.

ICE, its manufacture in Bengal, 210.
Interruptions of temperature determined
by the wind, 297; by distribution of
pressure, 298; not by meteors, 643;
use in forecasting weather, 646.
Ireland, climate of (see British Islands);
its influence on Great Britain, 273;
its importance on a system of storm-
warnings, 511.

Isabnormals, thermic, 275.

Isobarometric charts, Plates I., II.,
III.

Isocheimals, or lines of equal winter
temperature. See Isothermals for Jan-

Magnetism, terrestrial, in relation to the
sun and to the aurora, 610; to storms,
611.

Magnus, Professor, experiments on dia-
thermancy of dry and moist air,
345.

Mann, Dr, on climate of Natal, 561.
Marine barometer, 36.
Marriotte's law, 303.

Martin on decrease of temperature with
height in cold weather, 212.
Maury's ocean-charts, 21, 242, 564.
Maximum thermometers, 125.
Mean temperature, importance of re-
solving into the extremes which com-
pose it, 159, 160; vague meaning of,
157.

Meldrum, Charles, region of calms in
Indian Ocean in January, 110; on
rainfall of Mauritius, 405; on storms
of Indian Ocean, 553 to 563; a revolv-
ing storm, 566; on notification of
storms at Mauritius, 659 to 662.
Mercury, freezing-point of, 116.
"Merry dancers," 605.
Meteors, 641.

Milne's, Admiral Sir A., observation on
temperature of Gulf Stream, 243.
Minimum thermometer, 129.

Mist and fog, how caused, 346.
Mist on hills, 356.

Mistral, 497.

RADIATION of heat, 175; SOLAR, first dis-
cussed by Halley, 13; its effect on
earth's surface estimated by black-
bulb thermometer, 187; on land, 177;
on water, 183.

Radiation, why small in insular climates,
344; why great in elevated situations
and at the poles, 343; TERRESTRIAL,
191; first discussed by Lambert, 13;
how estimated, 197; its effects on dif-
ferent substances, 199; circumstances
affecting, 212.

Rain, general causes of, 392; specific

conditions required, 393; in relation
to atmospheric pressure, Chap. XI.
Rainbow, solar, 617; lunar, 620; extra-
ordinary, 619; supernumerary, 617.
Rain-cloud, 386.

Rainfall diminishes with the height
above the ground, theories to account
for, 398; cases of heavy falls, 400; re-
lation to storms, 514; in the region
of calms, 403; the tropics, 402, 407;
Hindostan, 404, 406; Europe, 408;
Mediterranean, 413; America, 414.
Rain-gauges, 395; size of, 396; position
of, 397.

Rainless regions of the globe, 399.
Rainy days, 401.