AEROLOGY. 
164 
quantity of nitrous air, viz. a quantity many times greater 
than that which water is wont to imbibe of it by agitation, 
or by any known means. When nitrous acid is combined 
with effential oils, a confiderable effervefcence and heat 
are produced, nearly as when the nitrous acid itfelf is 
pouicd upon thofe oils. 
Fluor Acid Air. Put fome of thofe minerals called flu- 
on , or fv/ble/pars, pulverized, into the bottle, and upon 
it pour fome concentrated vitriolic acid; then adapt the 
bent tube, &c. The fluor acid air is at firft produced 
without the help of heat; but in a Ihort time it will be 
neceffary to apply the flame of a candle to the bottle, by 
which means a confiderable quantity of this elaftic fluid is 
obtained. 
Alkaline Air. Let the ufual bottle be about half filled 
with volatile fpirit of fal ammoniac ; and, after applying 
the bent tube, See. let the flame of a candle be brought 
under the bottle, by which means the alkaline air will be 
produced copioully. 
A E R 
AEROMANCY,yi [front and /aavit?.] A fpecies of 
divination performed by means of air, wind, &c. See 
Divination. 
AEROMETRY,yi [from ur,g and fxil ps&>.] The fcience 
of meafuring the air. It comprehends not only the doc¬ 
trine of the air itfelf, confidered as a fluid body ; butalfo 
its preflure, elafticity, rarefaction, and condenfation. But the 
term is at prefent not much in ufe, this branch of natural 
phiiofophy being more frequently called pneumatics. See 
Pneumatics. 
AERONAUT,yi a perfon who attends and guides an 
air-balloon. See Aerostation and Air-balloon. 
AERONAUTIC A, f. [from and vavlixo;, derived 
from mv $, fliip.] The art of failing in a veffel or machine 
through the atmofphere, fuftained as a fliip in the fea. 
■AEROPHOBI, f. [from air, and fear.] 
According to Coelius Aurelianus, fome phrenetic patients 
are afraid of a lucid, and others of an obfcure, air, and 
thefe he calls aerophobi, So that, 
A E R 
AEROPHOBIA, f. is a fymptom of the phrenitis. 
AEROPHYLACEA,^ a term ufed by naturalifts for 
caverns or refervoirs of air, fuppofed to exifl; in the bow¬ 
els of the earth. Kircher fpeaks much of aerophylacea, 
or huge caverns, replete with 'air, difpofed under ground; 
from whence, through numerous occult p.affages, that 
element is conveyed either to fubterraneous receptacles of 
water, which, according to him, are hereby raifed into 
fprings or rivers, or into the funds of fubterraneous fire, 
which are hereby fed and kept alive for the reparation of 
metals, minerals, and the like. 
AEROSCOPY, f. [avia and ov.t/u.'] The obfervation 
of the air. 
AEROSIS,yi an imaginary refolution of the blood into 
vapour, fuppofed neceffary to the fupport of the vital 
fpirits, and faid to be brought about by the ventilation of 
the air during infpiration, in the manner that the flame of 
fuel is kindled by blowing it. 
AEROSTATION 
I S a fcience but very lately introduced into public no¬ 
tice. The word, in its primitive fenfe, denotes the 
fcience of fufpending weights in the air; but, in its mo¬ 
dern acceptation, it fignifies aerial navigation, or the art 
of navigating through the atmofphere. Hence alfo the 
machines which are employed for this purpofe are called 
aero/ats, or aeroflatic machines-, and, from their globular 
fhape, air-balloons. 
The romances of almoft every nation have recorded in- 
ftances 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 accompliflied. Before that time, indeed, 
Friar Bacon had written upon the fubjedt; and many had 
been of opinion, that, by means of artificial wings, fixed 
to the arms or legs, a man might fly as well as a bird : 
but thefe opinions were thoroughly refuted by Borelli in 
his Treatife De Motu Animalium , where, from a compan¬ 
ion between the power of the mufcles which move the 
wings of a bird, and thofe which move the arms of a man, 
he demonftrates that the latter are utterly infufficient to 
llrike the air with fuch force as to raife him from the 
ground. It cannot be denied, however, that wings of this 
kind, if properly conftrudled, and dexteroufly managed, 
might be fufHcient to break the fall of a human body from 
an high place, fo that fome adventurers in this way might 
poflibly come off with fafety; though by far the greateft 
number of thofe who have raflily adopted fuch fchemes, 
have either loft their lives or limbs in the attempt. 
In the year 1672, Biftiop Wilkins publifhed a Treatife, 
intitled, “ The Difcovery of the New World ;” in which 
he mentions, though in a very mdiftindt and confufed 
manner, the two principles on which the air is navigable; 
quoting, from Albertus de Saxoniaand Francis Mendoya, 
“ that the air is in fome part of it navigable; and upon 
this ftatic principle, any brafs or iron velfel (fuppofe a 
kettle), whofe fubftance is much heavier than that of wa¬ 
ter, yet being filled with the lighter air, it will fwim up¬ 
on it and not fink. So fuppofe a cup or wooden veliel 
upon the outward borders of this elementary air, the ca¬ 
pacity of it being filled with fire, or rather ethereal air, 
it mud neceffarily, upon the fame ground, remain fwim- 
ming there, and of itfelf can no more fall than an empty 
fliip can (ink.” This idea, however, he did not by any 
means purfue, but refted his hopes entirely upon mecha¬ 
nical motions, to be accompliflied by the mere ftrength ot 
a man, or by fprings, &c. and which have been demonftra- 
ted incapable of anfwering any ufeful purpofe. 
The only perfon who brought his fcheme of flying to 
any kind of rational principle was the Jehiit Francis Lana; 
cotemporary with Bifliop Wilkins. He, being acquainted 
with the real weight of the atmofphere, juftly concluded, 
that, if a globular veffel were exhaU'fted ol air, it would 
weigh 
