A E R O S * 
'fire; and this is entirely at the command of the aeronaut, 
as long as he has any fuel in the gallery. The inflamma¬ 
ble-air balloons have been generally raifed or lowered by 
diminifliing the weight in the boat, or by letting out fome 
of the gas through the valve : but the alternate efcape of 
the air in dcfcending, and difcharge of the ballad for af- 
cending, will by degrees render the machine incapable of 
floating; for in the air it is impoffible to fiipply the lofs of 
ballad, and very difficult to fupply that of inflammable 
air. Thefe balloons will alfo rife or fall by means of the 
rarefaction or condenfation of the inclofed air, occafioned 
by heat and cold. It has been propofed to aid a balloon 
in its alternate motion of al'cent and defcent, by annexing 
to it a veflel of common air, which might be condenfed 
for lowering the machine, and rarefied again, by expel¬ 
ling part of it, for railing the machine. But a veiled 
adapted to this purpofe mult be very ftrong; and, after 
all, the affiftance afforded by it would not be very confide- 
rable. M. Maunier, in order to attain this end, propofes 
to inclofe one balloon filled with common air in another 
filled with inflammable air; as the balloon afeends, the 
inflammable air is dilated, and of courfe compreffes the 
internal balloon containing the common'air; and, by dimi- 
nifhing its quantity, leffens its weight. If it fhould be 
neceffary to fupply this lofs, he fays it may be eafily done 
by a pair of bellows fixed in the gallery. Others have 
propoled to annex a fmall machine with rarefied air to an 
A T I O N. J 7? 
inflammable-air balloon by ropes, fit fitch a diftance that 
the fire of the former might not affect the inflammable air 
of the latter: the whole apparatus, thus combined, of 
balloons formed on the two principles of heated in¬ 
flammable air, might be raifed or lowered by merely in« 
creafing or diminifliing the fire in the lower balloon. 
Wings or oars are the only means of this fort that hav£ 
been tiled with fome fuccefs; and, as Mr. Cavallo ob-- 
ferves, they feem to be capable of confiderable improve-- 
ment. Although great effeCfs are not to be expected fronts 
them, when the machine goes at a great rate, the belt me« 
thods of moving tliofe wings are by the human ftrength 
applied fimiiarly to the oars of a waterman. They may 
be made in general of filk ftretched between wires, tubes, 
or flicks; and, when ufed, rnuft be turned edgewife when 
they are moved in the dire'Ction in which the machine is> 
intended to be impelled, but flat in the eppofite direction. 
Other contrivances have been made to direCt aeroftatic 
machines, but they have rnoflly been invented to effeCt a* 
power upon them as upon a fliip. It appears, however, 
that they can have no effeCt when a machine is only moved 
by the wind alone, becaufe the circumambient air is at rel? 
in refpeCt to the machine. The cafe is quite different with 
a veflel at fea, becaufe the water on which it floats (rands 
ftill while the veflel goes on; but it rnuft be time and expe¬ 
rience that can realile the expectations fuggefted by tliefe 
contrivances. 
IE S 
- AERSHOT, a town in the Netherlands, in the duchy 
of Brabant, and capital of the duchy of Aerfliot. It is 
feated on the river Demur, ten miles eaft of Malines or 
Mechlin, and eight north of Louvain. Lat. 51.15. N. 
Ion. 5. -v- E. 
/SRUGINOUSjffr//. anepithetgiven tofuch things as re¬ 
ferable or partake of the nature of the ritft of copper, 
lu medicine, the word is often applied to what is-dif- 
charged by vomitings of this colour, and alfo to the bile. 
AiRUGO, f. in natural hiftory, properly lignifies the 
rufl ot copper, whether natural or artificial. The former 
is found about copper-mines, and the latter, called ver- 
deVris, made by corroding copper-plates with acids. See 
VERDEG RTS. 
7 ERUSC ATORES,y. in antiquity, a kind of (Trolling 
beggars, not unlike gypfies, who drew money from the 
credulous by fortune-telling, See . It was alfo a denomi¬ 
nation given to griping exaCTors, or collectors of the re¬ 
venue. The Galli, orpriefts of Cybele, were called cernf- 
caiores magnet m'atris ; and p.ijrpayt/plai, on account of their 
begging or collecting alms in the ltreets. 
JES UXORIUM,/. in antiquity, a fum paid by bache¬ 
lors, as ;t penalty for living Angle to old age. This tax 
for not marrying feigns to have been firll impofed in the 
year of Rome 350, under the cenforfhip of M. Furius 
Camillus and M. Pofthumus. 
JEs per et LiBRAM-wasa formula in the Roman law, 
whereby purchafes and fales are ratified. Originally the 
phiafe feems to have been only ufed in (peaking of things 
ibid by weight, or by. the feales; but it afterwards was 
ufed on other occafiorrs. 
JE s Fi.avum, yellow copper ; among the Romans, an 
appellation given to the coarfer kinds of brafs. 
FEs Cai.da.rium, a term ufed by the German minera- 
lifts, for a fubflance which fometimes occurs to thofe who 
work upon cobalt, and is ufed for the making the fine blue 
colour called [malt. 
. JE s Us.tum, a chemical preparation, made of thin 
leaves of copper, fulphur, and nitre, placed JlratumJupcr 
Jlratum in a crucible, and let in a charcoal fire till, all the 
JE S C 
fulphur is confumed; after which, the copper is taken out 
of the crucible, and reduced to powder. Some quench 
the leaves of copper in vinegar, and repeat the calcina¬ 
tion. Its principal ufe is in colouring glafs, to which it 
gives a beautiful tinihire. It was formerly ufed in fur- 
gery, for deftroying fungous ffefli. If the burnt copper is 
made red-Jiot, and quenched intheoi lini nine times, then 
powdered, it takes the name of faffron of copper. 
AESCHINES, a Socratic philolopher, the fon of Cha- 
rinus, a faufage-maker. He was continually with Socra¬ 
tes; which occafioned this philofopher to fay, that the 
faufage-maker’s fon was the only perfon who knew how 
to pay a proper regard to him. It is faid tliat poverty 
obliged him to go to Sicily to Dionyfius the Tyrant; and 
that Ire met with great contempt from Plato, but was ex¬ 
tremely well received by Ariftippus; to whom he (heweef 
fome of his dialogues, and received from him a handfome 
reward. He would not venture to profefs philofophy at 
Athens, Plato and Ariftippus being in fuch high efteem; 
but lie fet up a fchool to maintain himfelf. He afterwards 
wrote orations for the Forum. Phrynicus, in Photius, 
ranks him amongft the belt orators, and ljientions his ora¬ 
tions as the ftandard of the pure Attic ftyle. Hermoge- 
nes has alfo fpoken very highly of him. He alfo wrote 
feveral Dialogues, of which there are only three extant: 
1. Concerning Virtue, whether it can be-taught. z. E- 
ryxias, or Erafiftratus; concerning Riches, whether they 
are good. 3. Axiochus; concerning Death, whether it is 
to be feared. M. Le Clerc has given a Latin tranflation 
of them, with notes and feveral differtations, intitlea Syi- 
va Philologicce . 
AiSClt YLlTS, the tragic poet, was born at Athens. 
Authors differ in regard to the time of his birth, Com© 
placing it in the 65th, others in the 70th, Olympiad; but, 
according to Stanly, who relies on the Arundelian mar¬ 
bles, he was born in the 63d Olympiad. He was the fon. 
of Euphorion, and brother to Cynegims' and Aminias, 
who diftinguiflied themfelves in the battle of Mara bon, 
and the fea-fight of Salamis, at which engagements JEt- 
chylus was likewife prefent. in this laft action, accord- 
