F.

air in fixed air, 62. proofs that
it is one of its component
parts, 64, 65, 66, 67, 68.
How to procure dephlogisti-
cated air, 146, 150, 151. ani-
mals live longer in it than in
any other, 147. Dr Pricfley's
objection, ib. Abbe Fontana's
opinion, 143, 149.
DEPHLOGISTICATED NITROUS
AIR, production of, 95, 106.
its qualities, 106. water a necef-
fary component part, 107.
proof of this, ib. iron another,
1c8. experiments with iron
filings, copper, &c. ib. Wa-
ter abforbs this air, 109. which
is expelled by heat, ib. other
peculiarities of it, ib.
DEPHLOGISTICATED WATER,
an expreffion used by Mr Ca-
radish for pure air, 42. See
DPHLOGISTICATED AIR.
DILATATION of the air, calcu
lations of the, 9.

DISEASES, occafioned by mine-
ral and animal effluvia, 12.
Fixed air preferibed as a re-
Amedy, in various, 62.

E.

FFLUVIA of animals affect the
air, 12.

IDER-DOWN yields pure air,

LASTICITY, one of the moft
important properties of the

5. feems to be peculiar to
pit, 6. caíy proof of it, 7. cap-
pable of fome diminution, ib. re-
Facts against the weight of the

air, 8. and increases in propor-
tion to its denfity, ib. experi
thents refpe&ting it, 9. effects
of its powers, 10.
LECTRICAL SPARKS, experi-
ments with, 55, 56. remark-
ably alter fixed air, 69. inquiry
whether their heat or light ef-
fects this change, 70. their ef-
fects upon alkaline air, 91.
AUDIOMETER, the principle of
its conftruction, 102. the ufe
of it, 117. is an exact teft of
the proportion of pure air in
the atmosphere, 118.
EXHALATIONS deleterious, im-
bibed by vegetables, 4. from
Copper and fulphur mines, ef-
fects of, 12.
EXPANSION of the air. See E-

LASTICITY.

EXPERIMENTS fometimes fail in
the ableft hands, 21.

EXPLOSION takes place on mix-
ing pure and inflammable airs,

31.

57. abounds in a great variety
of substances, ib. its proper.
ties, ib. 131, 132, 133. pro-
portion to common air, 59.
and weight, ib. proofs and
comparative calculations of
this, 58, 59, 60. its powers, 61.
is both a poifon and a medi-
cine, ib. is the loweft of acids,
ib. but separates cils, fulphur,
&c. from other fubftances, ib.
Chemifts long ignorant of its
origin, 62. is produced from
pure air and phlogifton, ib.
by various fubftances, ib. 62,
64, 65. proofs of this, 66, 67,
68. is remarkably altered by
the electric fpark, 69. experi-
ments whether this is effected
by the heat or light of the elec-
tric spark, 70. quantity of fixed
air expelled from the different
fubftances, 71. Artificial pro-
duction of it, 119. by fermen-
tation, 120, 121, 122, 129. by
heat, 123, 124, 125, 126, 127.
by acids, 128, 130.
FLAME, fupported by pure air,
30. grows larger and brighter
in it, ib.

FLOWERS Contaminate air in the
night, 20.

FLUOR ACID AIR, its proper-

tics, 113. how to obtain it,

ib. 153.
FONTANA, Abbe, his experi-
ment to afcertain the compo-
fition of pure air, 36. his dan-
gerous experiment with in-
flammable air, 86.
FRENCH BEANS, experiment
with, 20.
FRENCH PHILOSOPHERS, their
opinions of pure and inflam-
mable airs, 43. controverted
by others of them, 44. deny
the existence of phlogifton, 86.
FRUITS contaminate common
air, 20.

FUR of a hare produces pure air,

GRAVITY of the air, one of its
moft important properties, 5.
its proportion to that of wa-
ter, ib. proof of it, ib. phono-
mena depending on it, 6.
GREEN MATTER, in the bottom
of ftagnant waters, yields pure
air, 20. confists of animalculæ,

22.

H.

HAIR, HUMAN, affords fome
pure air, 23.

HALES, Dr, his calculations of
the compreffibility of the air, 9.
HALLEY, LA, his opinion of the
compreffibility of the air, 9.
HARE. See FUR.
HEAT, produces more pure air
applied fuddenly, than flowly,
15. pure air obtained from dif
ferent minerals by heat alone,
16. experiments with heat,
light and water, 27, 28. heat
increased by pure air, 30. ne-
ceffary to produce inflamma-
ble air, 73. the more fudden
the heat, the greater the quan-
tity of that air, ib.
HEPATIC AIR, produced from
various fubftances, 116. fatal
to animal life, ib. its gravity,
ib. and other properties, ib.
HOMBERG'S pyrophorus, expe-
riment with, 105.
HOUSE-WORT, the plant, affords
pure air, 23. its leaves yield
more and fuperior in quality,
ib.

I.
ICE, air the cause of its bursting,
10. as quickly diffolved by
alkaline air, as by fire, 91.
INFLAMMABLE AIR, mixed with
pure air, explodes, 31. is
imbibed by the calces of me-
tals, 39. contains water, 41.
is a conftituent part of it, ib.
when and by whom firfl difco-
vered, 72. its fatal effects long
known to miners, ib. produ-
duced from all putrid fub-
flances, ib. its qualities, ib.
85. phænomena in hot cli-
mates, 72. various fpecies of
it, 73. and methods of pro-
curing it, ib. 74, 75, 76, 77.
charcoal convertible into it,
78. water neceffary to its pro-
duction, ib. proofs of this, 79.
Differences of the various kinds
of inflammable air, 80, 81.
when decompofed, it produces
fixed air, 82, 83, 84. readily
unites with water, 85. fuppo-
fed by French chemifts to be
a fimple element, 86. plants
grow pretty well in it, ib.
willows abforb it largely, b.
1 i 2
moft

252

moft animals die in it, ib.
Fontana's dangerous experi-
ment with it, ib. it poffeffes
little refractive power, 87. ar-
tificial fires made with it, ib.
will not answer the purpose of
gun-powder, ib. How to pro-
duce inflammable air, 134. en-
tertaining experiment with it,
ib. Dr Priestley's methods, 135,
136, 137. Mr Cavendish's, 137.
INGENHOUSZ, Dr, bis discoveries
in aerology, 18, 19. procures
pure air from various plants,
20. his estimate of the propor-
tion between pure and noxi-
ous air yielded by plants, 21.
his theory rendered dubious,
22, and combated, 28.
INSECTS can live in phlogiftica-
ted and inflammable airs, 86.
but die in nitrous air, 99.
IRON imbibes pure air, 39, 40.
the calx of, revived by in-
flammable air, 40. the fame
piece of, will ferve for many
experiments, 41. recovers its
phlogifton by inflammable air,
ib.
IRON TURNINGS, filings, or
fcales, experiments with, 38,
39, 40. 62, 75.

K,
KIRWAY, Mr, his opinion of
pure air, 43. his eftimate of
the proportion and weight of
fixed air, 57, 58, 59, 60. dif-
covers the nature and princi-
ples of it, 62. his experiments
with inflammable air, 85. his
calculation of the gravity of
alkaline air, 91. nitrous air,
103. his opinion of hepatic
air, 116.

L.

fun produces moft, ib. See
SUN.

LIME, flacked, yields pure air,

14.

་

NASTURTIUM INDICUM yields
pure air, 20.
NITRE, by diftillation, yields
pure air, 15. deflagrated with
charcoal produces phlogiftica.
ted air, 55.
NITRE, THE SPIRIT OF, useful
in procuring pure air, 14.
NITROUS ACID, a powerful
agent in procuring pure air,
14, 16. explanation of its pro-
duction, 42. experiment to
reduce atmospherical air to it,
55. a small proportion not re◄
ducible, ib.

NITROUS ACID Air, definition
of, 111. how procured, ib. its
properties, ib. experiment
with it, ib.
NITROUS AIR, a teft of the pu-
rity of dephlogifticated, 33,
38, 102, 143. does not dimi-
nifh phlogisticated air, 55.
plentifully procured from va-
rious fubftances, 96, phono-
mena refpecling the produc-
tion of it, 97. qualities of it,
98. deftructive to both animal

INDEX.

and vegetable life, 99. is ab
forbed by various acids, 10c,
IOI, is a ftrong antifeptic,
102. its specific gravity, 103,
and conftituent principles,
104. supposed by some to be
fimple fubftance, ib. water a
neceffary ingredient in it, 105.
is diminished by the electric
fpark, ib. how to produce
it, 139, 140, 141, 142, 144
156. materials, 140. quantity
obtained from each, 141. dif
ficulty attending the produc
NOXIOUS AIR, experiments o
tion of it, 156. phænomena, ib
purifying, 18, 19.

0.
OCEAN, waters of the, yiel
pure air, 29.

Oil of fulphur, difficult to b
procured in a dry atmosphere

PASCAL, Mr, his estimate of th
preffure of the atmosphere,
PEA PLANT, experiment wit
the item of one, 23.
PEPPERMINT purifies contam
nated air, 18.
PHLOGISTICATED AIR, the foo
of plants, 21, 35. argument
respecting its tranfmutation
52. Dr Priestley's discoverie
experiments and inference
ib. properties of this air, 5.
55. is fatal to animal life, 5.
its component parts, ib. ap
paratus for producing it, s
when deprived of its phlogi
ton is reduced to nitrous acic
55, 56. a fmall proportion c
it not reducible, 55. by mean
of the electrical fpark unite
with dephlogisticated air, it
and becomes nitrous acid, it
is not diminished by lime wa
ter, cauftic alkalis or nitrou
air, ib....
PHLOGISTIC proceffes promo
ted by pure air, 31.
PHLOGISTON, abforbed by com
imon air in burning, 14. melio

rates tainted air, 18. recover
ed by iron, 41. firft discover
ed by Stahl, 47. fuppofed to
diminish air, ib. and to be a
principle of pofitive levity, ib
other wonderful properties
afcribed to it, ib. thefe opini.
ons checked, 48.- and its exi-
tence denied, ib. 86. the doc
trine of it carried too far, 51.
PLANTS AQUATIC. See AQUA

TIC.

PLANTS correct bad air, and im-
prove common, 18. but con-
taminate it in the night, ib.
thele

thefe properties not poffeffed
by all plants, 19. experiments
with particular plants, 23.
plants grow in inflammable
air, 86.

POISONOUS VEGETABLES yield
pure air, 20.

POPULUS NIGRA, experiments
with the cotton of, 25.
PRECIPITATE PER SE, experi-
ment with, 40.

PRESSURE. See GRAVITY.
PRIESTLEY, Dr, the firft difco-
verer of pure air, 14. his me-
thod of obtaining it, 16, 17.
his experiments, as to its pu-
rity, 33, 34. other properties,
33. and compofition, 36, 38.
his experiments' with metals,
38, 39, 40, 41. his opinion of
the component parts of pure
air, 43. his doubt and difficul-
ty, 44, 45. defcription of his
apparatus, 46, and experi-
ments to folve them, ib. his
discovery of water emitting
pure air, 52. illuftrated by
experiments, ib. his experi-
ments refpecting fixed air, 62.
with charcoal, 63. iron, 64.
zinc and other minerals, 65.
his decifive proofs of his the-
ry, 66, 67, his methods of
btaining inflammable air, 73,
74 75. farther experiments
respecting it, 76, 77, his dif
covery refpecting charcoal, 78.
of fulphurated inflammable
air, 88. and of alkaline air,
91. his experiments with these,
89, 90, 91, 92. discovers a
new acid air, 115.*
RINGLE, SIR JOHN, his opini
on of the antifeptic powers
of fixed air, 132.
UMP. See AIR-PUMP and
WATER.

JURE AIR emitted by vege-
tables, 4. See DEPHLOGIS
TICATED. Copiously procur-
ed from pump water, 20.
UTREFACTION, air the caufe
of, 10. will not proceed in
vacuo, ib. fixed air preserves
the human body from, 132.

Q.

ANTITY of preffure of the
air, on the earth's surface, 5.
JUICK-LIME, pure air obtained
from, 14.

R.
RESPIRATION diminishes air, 47.
Di Prieftley's theory of it, 48.
impugned by Lavoifier, ib. 49.
his experiments and inferen-
ces, ib. so. eftimates of, 147.
LOOTS of plants yield bad air,

air, ib.
RUSSIAN HARE.

See FUR.

S.
SCHEELE, Mr, his method of
procuring pure air, 15. his
experiment with it and phof-
phorus, &c. 32. Difcovers
fluor acid air, 113. conftructs
an eudiometer, 117.
SILK, raw, yields pure air, with
water, 22.
SLAG iron. abforbs inflammable
air, 40. and becomes perfect
iron, 41. See IRON.
SPARROW, experiment with a,50.
STAHL, Dr, the difcoverer of
phlogiston, 47.
STELL, melted, imbibes pure
air, 40.

STONES corroded by air, 11.
SUGAR, an antifeptic, 132.
SULPHURATED INFLAMMABLE
AIR, discovery of, 88. phæno-
mena attending it, ib. 89.
produced from manganese, ib.
and iron, 90.
SULPHUR, liver of, abforbs pure
air, 55.
SULPHUR, oil of, beft obtained
in moist air, 12. effluvia of
the mines of, a cause of epi-
demic difeafes, ib.

SUN, the light of the, enables

plants to correct bad air, 18.
and to make pump water
yield pure air, 20. fuperior to
artificial light, 22. experiments
by expofure to it, 24. quanti
ty and quality of pure air pro-
duced by it from water, 27.
pure air produced from fea
water, by the fun's light and
heat, 29.
T.
THOMSON, Sir Benjamin, his
difcoveries, 22, and experi-
ments, ib. 23.
TUNGSTEN yields pure air by
heat, 16.

TURNINGS, IRON. See IRON.
TURPENTINE trees afford pure
air, 26:

V.

ing the atmosphere, 21.
VITRIOLIC ACID, ufeful in pro-

curing pure air, 17.
VITRIOLIC ACID AIR, compofi-
tion of, 110. and properties,
ib. procured from metals, ib.
and other fubftances, ib. how
to produce it, 157.
VITRIOL, OIL OF, used in pro-
curing pure air, 14, 17.
VOLTA, Mr, his fcheme, of
fubftituting inflammable air
for gun-powder, proves abor-
tive, 87.

W.
WARLTIRE, Mr, his method of
procuring pure air, 14. and
of trying the refractive power
of inflammable air, 87.
WATER, afcent of, depends on
the gravity of the air, 6. com-
bined with air, forms fogs,
II. quantity and quality of
pure air produced from water
by heat and light, 27, 28.
water produced by the union
of pure and inflammable airs,
40, 41. which are its confti-
tuent parts, 41. difficulties
refpecting its production from
their deflagration, 44. obtain-
ed this way in great quantities,
but not conftantly, or uni-
formly, 45, 46. apparatus for
this purpose, 46. pure air
emitted by water, 52. Dr
Priestley's experiments in
proof of this, ib. water ne-
ceffary to produce inflam-
mable air, 78. abforbs alka-
line air, 91.
WATER, PUMP, yields pure air
copiously, 20.

WATER, SEA, yields pure air,

AEROMANCY. n. S. [ang and parks, Gr.] The art of divining by the air. Di&.

AEROMANCY, in antiquity, included the bufinefs of augury, and aufpicia; the rules of prediction from uncommon winds, ftorms, fhowers, and other prodigies. Modern authors speak of a more rational aeromancy, meaning by it, the art of foretelling the changes and variations in the air and weather, winds, ftorms, and the like. Morhof advances confiderations for reducing aeromancy to a certainty, by means of a regular feries of meteorological obfervations. But though many fuch have been inftituted with great care in many parts, this art has hitherto made very fmall progrefs. Of this kind is Auxham's book De Aere. Barometers, thermometers, hygrometers, and anemometers, are of confiderable ufe in this kind of acromancy. Mizoldus has published a body of rules for foretelling ftorms, &c. drawn partly from vulgar obfervation, and the experience of mari. ners, partly from aftrological confiderations; under the title of AEROMANTIA.

AEROMANTIC, belonging to divination by the air. Bailey.

ÆROMELI, a name given to honey, and alfo to manna. See DROSOMELI.

* AEROMETRY. n.s. [úng and μígia.] The art of meafuring the air. Dia.

AEROMETRY, Comprehends not only the doctrine of the air itself, confidered as a fluid body; but alfo its preffure, elafticity, rarefaction, and condenfation. But the term is at prefent not much in ufe, this branch of natural philofophy being more frequently called PNEUMATICS, winch fee. C. Wolfius, profeffor of mathematics at Hall, having reduced many of the affectious of this fluid to geometrical demonstration, first pub.

lifhed Elements of Aerometry, at Leipfic, in 1709, in High Dutch, and afterwards more largely in Latin. Thus is the doctrine of the air incorpo rated into the mathematical sciences.

AERONAUT, a perfon who mounts in and guides an air balloon. See AEROSTATION am AIR BALLOON.

AERONAUTICA, [from ang and varies, de rived from us, a bip ;] the art of failing in a verte or machine through the atmosphere, fuitained a a fhip in the fea. See AEROSTATION.

AEROPHYLACEA, in natural hiftory, fub terraneous receptacles of air or wind. [from ! air, and quλann, cuftodia, keeping.] Kircher speak much of aerophylacea, huge caverns, replete wit air, difpofed under ground, from whence, throug numerous occult paffages, that element is conve ed either to fubterraneous receptacles of water which are raised into fprings or rivers, or into th funds of fubterraneous fire, which are hereb fuppofed to be fed for the reparation of metal minerals, and the like.

* AEROSCOPY. n. . [àng and exile, Gi The obfervation of the air. Dig.

AEROSIS, among the ancient physicians, d notes the act whereby the blood is attenuated ar converted into an aura, for the fupport of the v tal fpirits, and the maintenance of the flame. life.

AEROSTAT, a machine employed in aeroft

tion.

AEROSTATIC, adj. belonging to aerostatis AEROSTATICA, AEROSTATICS, [from @ and saris, from 15, tatuo;] is used by for authors for AEROMETRY. It is properly t doctrine of the weight, preffure, and balance the air and atmosphere.

new. The word is derived from Ane, aer, air, and Isana, ftare, to ftand, and originally fignifies the fufpenfion or placing of bodies in the air; but, in its modern acceptation, is applied to aerial navigation, or the art of failing in that element. The machines employed for this purpofe, which, from their globular form, are called air balloons, are likewife ftiled aeroflats, or aeroflatic machines.

SECT. I. HISTORY of AEROSTATION. (2.) The fabulous histories of almost every nation have recorded inftances of perfons being carried through the air, both by the agency of fpirits and by mechanical inventions; but till the time of the celebrated Lord Bacon, no rational principle appears ever to have been thought of, by which this might be accomplished. Friar Bacon indeed had written upon the fubject; and many had fuppofed, that, by means of artificial wings a man might fly as well as a bird; but thefe opinions were refuted by Borelli in his treatife De Motu Animalium, where, from a comparison between the power of the mufcles which move the

of a man, he demonftrates, that the latter are u terly infufficient to ftrike the air with fuch for as to raife him from the ground.

(3.) In the year 1672, Bithop Wilkins publis ed his " Difcovery of the New World," in whic he certainly feems to have conceived the idea raifing bodies into the atmosphere by filling the with rarefied air. This, however, he did not bi any means purfue, but refted his hopes upon m chanical motions, to be accomplished by huma ftrength, or by fprings, &c. which have been pro ved incapable of anfwering any useful purpo The Jefuit Francis Lana, his cotemporary, pro pofed to exhauft hollow balls of metal of their air and thus occasion them to afcend. But thoug the theory was unexceptionable, the means wer certainly infufficient to the end: for a vefiel o copper, made fufficiently thin to float in the at molphere, would be utterly unable to refift the external preffure; which being demonftrated, no attempt was made on that principle.

(4.) In 1709, Friar Guzman applied to the king of Portugal for his patronage of a flying ma

chine