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FERIAL Acid, in Chemistry, carbonic acid. See science of describing the air and its properties. A term AroCHEMISTRY, Div. ii.
in little use; but formerly embracing what is now GRAPH ÆRIAL PERSPECTIVE, that branch of the science of treated under Air, Aerology, Meteorology, &c.
AERO. Perspective which regards the relative diminution of JEROLITHS (ano, air, and Ados, a stone), a name
NACTICE the colours of bodies in proportion to their distance sometimes given to those mineral substances which from the eye. See Colour and PAINTING, Div. ii. occasionally fall through the atmosphere. Some have
ÆRIFORM Fluids,in Chemistry, a name sometimes considered them as concretions actually formed in the given to the different gasses. See CHEMISTRY, Div. ii. air, but no satisfactory theory respecting them has yet
ÆROGRAPHY (ang, air, and ypaow I write), the been given.
A Ë R O N A UTIC S.
Defuition. AERONAUTICS, from anp, the air, and vavrıkn, the utterly unable to resist the external pressure to which“Experimer
art of narigation ; signifies the art of navigating through they must necessarily be exposed. The second case we of Gusuan
In sketching the history and progress of this art, the air, which ascended to the height of 200 feet. We
discovery of the specific gravity of inflammable air, suggestion. Principle. From principles long known, and which will be found suggested that if a bladder sufficiently light and
established in our treatise of Hydrostatics, it follows, thin were filled with this air, it would form a mass that any body which is specifically lighter than a fluid, lighter than the same bulk of atmospheric air, and rise will float in it; and consequently a mass bulk for bulk in it. This thought was suggested in his lectures in lighter than the atmosphere, or the air encompassing 1767 and 1768; and he proposed, by means of the the earth, will be buoyed up by it, and will ascend for allentois of a calf, to try the experiment: this, howthe same reason that a cork, or a blown bladder would ever, he was prevented by his other employments from rise in water, supposing either of these to be in the first carrying into effect. The possibility of constructing a instance immersed at any given depth below its surface. vessel, which, when filled with inflammable air, would
If the atmosphere were every where of the same ascend in the atmosphere, had occurred also to Mr. density as at the terrestrial surface, and a mass could Cavallo about the same time; and to him belongs the Cavallo's be obtained specifically lighter, such a mass would not honour of having first made experiments on this sub- experionly rise in the first moments, but it would continue ject in the beginning of the year 1782, of which an ments. to ascend to the upper surface of this medium; and account was read to the Royal Society on the 20th of having attained that situation, it would there remain June in that year. He first tried bladders, but the in a quiescent state, or float along upon the surface, thinnest of these, however, scraped and cleaned, were having neither the power to ascend, nor any tendency too heavy. In using China paper, he found that the to descend, except that which is resisted by the upper inflammable air passed through its pores like water pressure of the Auid. But as the air is compressible through a sieve; and having failed of success in blowand elastic, its density continually decreases as we ing this air into thick solutions of gum, varnishes, and ascend, and therefore a body can only rise in such a oil paint, he was under the necessity of being satisfied medium to an elevation at which the air is of the same with soap balls, which, being inflated with inflammable density as itself.
air, by dipping the end of a small glass tube, connected This principle,as we have observed above,has been long with a bladder containing the air, into a thick solution known, and various projects have in consequence been of soap, and then gently compressing the bladder, formed for producing a mass of sufficient rarity to effect ascended rapidly in the atmosphere; and these are the purpose ofaerialascensions; but most of these schemes doubtless the first infiammable air balloons that ever were merely imaginary, and are entitled to little notice: were made. we shall therefore only mention two of them, which The practice and science of aëronautics is not, how- Montgol
seem to approach the nearest in idea to the present ever, to be considered as springing from the above fier's. e. pe Proposition practice of aeronautics. The jesuit Francis Lana, con- experiments
, for while
these were yet unfinished, and mineat. of Lana. temporary with bishop Wilkins, proposed to exhaust hol- even perhaps before the soap balls had been made to
low balls of metal of their internal air, and by that means ascend, Stephen and John Montgolfier, natives of An to render them specifically lighter than the atmo- nonay, in France, and masters of a considerable manusphere, and determine them to ascend, as represented in factory there, had turned their attention to the subPlate 1. This idea, in a theoretical point of view, is un- ject, and in the same year- their first experiment was exceptionable, but the means were certainly insufficient made at Avignon ; by applying to an aperture in a fine for the practical performance of the experiment; for silk bag some lighted paper, which rarified the air, and vessels of copper of any manageable dimensions, made caused it to ascend to the perpendicular height of 70 sufficiently thin to float in the atmosphere, would be feet. After this, various experiments were tried upon
ering of grain ascended with M. Girond de Villette, to the
Afro a large scale, which greatly excited the public curiosity. On the 21st of November, 1783, M. Pilatre again AEROVALTICS. An immense bag of linen, lined with paper, and con ascended with the marquis d’Arlandes. Their voyage
NAUTICS. taining upwards of 23,000 cubic feet, was found to occupied about 25 minutes, the aëronauts having, have a power of lifting about 500 lbs. including its own in that time, passed over a space of about five miles. weight. Burning chopped straw and wool under the In this ascent it appears there was some danger of the aperture of this machine, it immediately occasioned it machine taking fire, the marquis having observed seveto swell, and afterwards to ascend into the atmosphere ral holes made by the fire in the lower parts; the apwith such rapidity, that in ten minutes it had risen to plication, however, of a wet sponge was found to be a height of 6000 feet, when its force being exhausted, it sufficient to stop the progress of combustion, and fell to the ground at the distance of 7668 feet from they descended in safety. the place whence it departed.
This last voyage may be said to conclude the history Not long after this, one of the brothers, invited by of aërostatic machines elevated by means of heated air: the Academy of Sciences at Paris to repeat his experi- for they were found in some degree inconvenient, on acment at their expence, constructed a large balloon of count of the impossibility of keeping up the elevated an elliptical form. In a preliminary experiment, this temperature of the enclosed air, without the continued balloon lifted from the ground eight persons who held renewal of fuel, and that in considerable quantity; it, and would have ascended with them, had not others whereby the aëronauts were exposed to great danger, came quickly to their assistance.
from the occasional sudden and unavoidable expansion On the following day the machine was filled by the of the flame, and their inability to command that uni30 BERLIN 8 combustion of fifty pounds of straw, and twelve pounds formity of rarefaction so necessary to the safety of the Te
of wool, with which it soon became inflated, and sus voyage.
in a wicker cage, were sent a sheep, a cock, and a whose specific gravity, in a tolerably pure state, is at and duck. The entire success of this experiment, however, least twelve times lighter than atmospheric air.
We was prevented by a sudden gust of wind, which tore have noticed the suggestion to which this discovery had the machine in two places near the top before it as given rise in the lectures of Dr. Black, and the experi
cended; still, however, it was estimated to have risen ments of Cavallo, by which the truth of these suggesthe 1440 feet; and after remaining in the air about eight tions was in part demonstrated. It was very natural,
minutes, it fell to the ground, about two miles from therefore, after the success that had attended the ex-
philosophers should be drawn towards the completion
The first machine of this kind was launched on the Charles and
Roberts asweights, and consequently men, with great safety, continent by M. M. Roberts and Charles, in 1783, and
cend with Fistre de M. Pilatre de Rozier offered himself to be the first such was the great convenience of these machines
an hydrogen aërial adventurer, with a new machine, constructed in compared with those elevated by heated air, that they gas balioon. the fauxbourg of St. Antoine. This was of an elliptical soon became almost exclusively adopted; yet even or oval form, 48 feet in diameter, and 74 feet in height, these possessed some disadvantages, particularly that and was elegantly painted and ornamented. A
proper of the aëronaut not being able to raise or lower them gallery and grate enabled the aëronaut to supply the without a loss of ballast in the first instance, and of fire with fuel, and thus to keep up the machine as long gas in the latter; the filling of them was also attended as he pleased; the weight of which, with the apparatus, with considerable expense. These defects suggested &c. was about 1600 lbs. On the 15th of October, the idea of enclosing a bag of common air, in one of 1783, M. Pilatre, placing himself in the gallery, in- inflammable air, whereby, in varying the temperature Alated the balloon, and permitted it to ascend to the of this inner balloon, the whole apparatus could be height of 84 feet, where he kept it afloat about four or raised or lowered ad libitum. five minutes; after which it descended very gently: The first attempt conformably to this idea, was made Ascent of but such was still its tendency to ascend, that it re- by the duke de Chatres. He placed a small balloon leadinuke de bounded to a considerable height after touching the within the greater one, the former being filled with ground. He then repeated the experiment, and as common air by means of a pair of bellows, when necescended to the height of 210 feet; he afterwards rose sary, viz. whenever it was thought proper to descend, 262 feet, and in the descent this third time, a gust of it being supposed, that the machine would thus become vind having blown the machine over some trees in an heavier, and the air in the outer balloon condensed, adjoining garden, M. Pilatre, by throwing a little fuel and consequently, that the ascent or descent might be on the fire, rose again sufficiently to extricate himself effected at pleasure. The circumstances, however, of from this difficulty; and thus demonstated the practica this voyage were so unfavorable, that it could not be bility of the management of such machines.
ascertained whether or not the experiment would have
the weather being so boisterous during the whole
A ÜRO- tatic machine by bags filled with common air, being 12th of June, accompanied by the president de Verly. A ÉRO.
which was to put a small aërostatic machine with morning, the mercury in the barometer standing at 291
not rise to a very great elevation, they enjoyed an Fatal ascent This scheme was unfortunately put in execution by agreeable temperature, and could easily, by observing of Pilatre and Ro
the celebrated Pilatre and M. Romaine. Their inflam- the situation of the different villages scattered below maine. mable air balloon was about thirty seven feet in dia- them, trace out their route with tolerable accuracy on
meter, and the power of that of rarefied air was about the surface of the map. By nine o'clock they had
coast, on the 7th of January of the same year. prisoner by the farmer and several peasants, who inGuyton We have introduced this account of the unfortunate sisted upon his paying the damages that the curiosity Morrean Pilatrc de Rozier, in consequence of the similarity of of his followers had occasioned. Anxious to get clear and Ber
his experiment to that of the duke de Chatres; but of such troublesome attendants, he persuaded them,
on a ground of dazzling whiteness. After a voyage of ployed, the huntsmen gallopped up to him. He then Guyton an hour and a-half they alighted safely at about 15 mounted a third time, and passed through a dense Morveau's miles distance from the place of their ascent.
body of clouds, in which thunder followed Aashes of M. Guyton Morveau ascended a second time on the lightning in quick succession. The thermometer fell
AERO. 10 21°, but afterwards, when the balloon had reached About this time Mr. Sadler made his first aërial AÉROBALTICS. the height of 3,000 feet, regained its former point of 56°. excursion from Oxford; since which date he has
NAUTICS. In this region the aëronaut remained till nearly nine formed several other voyages to the upper regions. o'clock, and at this time witnessed the setting of One of these was attended with peculiar circum- Sadler. the sun; immediately after which, he was involved stances, as will be seen in the subsequent part of this in thick masses of thunder clouds: lightnings flashed article. on all sides, succeeded by loud claps of thunder, while Perhaps the most daring attempt that had yet been Blanchard snow and sleet fell copiously around him. The ther- made, was that of M. Blanchard and Dr. Jeffries and Jeffries, mometer, was then sunk to 21°, as he perceived across the straits of Dover. This took place on the by the help of a phosphoric light which he had struck 7th of January, 1785, being a clear frosty morning, for that purpose.
with the wind barely perceptible at N. N.W. The In this tremendous situation the intrepid adventurer operation of filling the balloon began at 10 o'clock, and remained three hours, the time during which the storm a little before one o'clock every thing was ready for lasted. The balloon was affected by a sort of undulating their departure. At one o'clock M. Blanchard ordered motion, upwards and downwards, occasioned, as he the boat to be pushed off, which then stood only two imagined, by the electric action of the clouds. The feet distant from that precipice, so finely described by lightoing appeared excessively vivid; the thunder was Shakespeare in his tragedy of King Lear. As the balsharp and loud, and preceded by a sort of crackling noise. loon was scarcely sufficient to carry two men, they
A calm at length succeeded, when he had the pleasure were obliged to throw out all their ballast, except three 11 of seeing the stars, and embraced the opportunity of bags of sand, of ten pounds each; when they rose
taking some necessary refreshment. At half past two gently, but made little way, on account of the wind
in the morning, day began to appear, and he resolved being very slight. At a quarter past one the baагу to descend, which he accomplished about a quarter rometer, which on the cliff stood at 29.7, was fallen to
before four, having already witnessed the setting and 27:3, and the weather proved fine and warm for the
under circumstances at one time the most pleasant, several vessels, they found that the balloon, at fifty cally and at others, the most terrific it is possible to minutes after one, was descending, and they immeimagine.
diately threw out a sack and a half of their ballast; but Leardi's
The first aërial voyage in England was performed on this being found insufficient, their descent being still the land in the 15th of September, 1784, by Vincent Lunardi, a more rapid than before, they threw out all that re
native of Italy. His balloon was made of oiled silk, mained: but even this was found to be ineffectual ;
painted in alternate stripes of blue and red, and in they therefore next cast out a parcel of books : this -a, diameter, it measured thirty-three feet. From a net caused the balloon to ascend, at a time when they were
which went over about two thirds of it, descended forty- about midway between France and England; viz.
At a quarter or gallery was attached. There was no valve; its neck, past two, finding themselves again descending, they ELT which was terminated in the form of a pear, being the threw away the remainder of their books, and about
aperture through which the hydrogen gas was intro ten minutes after, had a most enchanting prospect of
The second aerial voyage in England, was undertaken last stript off their clothes, and fastening themselves salseidon by M. Blanchard, and Mr. Sheldon, professor of ana to certain slings, intended to cut away the boat as
tomy to the Royal Academy. They ascended at their last resource. They had, however, now the sa-
so rare, that a pigeon sent off from the sented M. Blanchard with a gift of 12,000 livres, and
period above stated, viz. 1786; but it would be useless
AERO. to attempt a mere enumeration of the various voyages balloon. At six the operation of filling being completed, An NAUTICS. that have been since undertaken; we shall therefore M. Garnerin placed himself in the basket, and the NAUTI
select only such as have been made with particular whole machine and apparatus rose majestically amidst scientific views, or which have been performed under the acclamation of innumerable spectators. The
circumstances that render them of particular interest. weather was the clearest and pleasantest imaginable, Garnerin Blanchard was the first who constructed parachutes, the wind was gentle, and about west by south, and descends in and attached them to balloons, for the purpose of se- consequently the balloon moved slightly in the opposite a pamchute.
curing himself from the fatal consequences of a rapid direction. in less than ten minutes, the machine, with fall, in case any accident happened to his machine. its attendant and appendages, had ascended to an In one of his excursions from Lisle, about the end of immense height, and M. Garnerin in the basket was August, 1785, when he traversed a distance of more scarcely perceptible. Every eye was now directed to than 300 miles without halting, he let down from a the adventurous aëronaut; in a moment the rope was great height a dog, by means of a basket fastened to 'cut, and the balloon and parachute separated from each a parachute, and the animal reached the ground other. Before the latter opened, it fell with a great unhurt. Since that period, the practice and manage- velocity, and as soon as it was expanded, which took ment of the parachute have been carried much farther place a few moments after, the descent became more by other aërial adventurers, and particularly by M. gradual, but still attended with a very fearful appearGarnerin, who has dared repeatedly to descend from ance, the whole apparatus vibrating like the pendulum the region of the clouds by that very slender machine. of a clock, but in such large ares that several times the
This ingenious Frenchman visited England during parachute, and the basket with Garnerin, seemed to be the short peace of 1802, and made four fine ascents in nearly horizontal; the extent, however, of the vibrahis balloon; in the last of which, September 21, he un tions diminished as he came nearer the ground, which dertook the singular and desperate experiment of de- he ultimately reached, as we have already said, in a scending in a parachute. The ascent took place from field in St. Pancras, but with so much violence as to St. George's Parade, North Audley-street, London, and throw him on bis face, by which accident he received he descended in a field near the Small-pox Hospital, some severe cuts and bled considerably. He seemed Pancras. The balloon was of the usual sort, viz. of much agitated, and trembled excessively at the moment oiled silk, with a net, from which ropes proceeded, he was released from the basket. One of the stays of and were terminated in, or were joined to, a single rope the parachute had given way, an untoward circumat a few feet distance below the balloon. To this rope stance which deranged the apparatus, and threatened the parachute was fastened. The construction of the the adventurer during the whole of his descent, with machine, with the mode of fastening, may be described immediate destruction. as follows. It consisted in the first place of thirty-two The voyages which we have hitherto detailed, were gores of white canvas, formed into an hemispherical undertaken merely as matters of curiosity, and little of case of twenty-three feet diameter, at the top of which scientific research had yet been attempted by them. was a truck, or round piece of wood, ten inches broad, Philosophers, liowever, now became anxious to turn having a hole in its centre, admitting short pieces of them to a more useful purpose, and to determine, by tape to fasten it to the several gores of the canvas. the means which they afforded, what circumstances Several ropes about thirty feet long, which proceeded attended the magnetic and electric action in the upper from the edge of the parachute, terminated in a common regions of the atmosphere; as also the proportions of joining, from which the shorter ropes proceeded; and the component parts of the air in places remote from to the extremities of these a circular basket was fastened, the surface of the earth. intended for the reception of the adventurer. Now the The first aërial voyage which can be said to have single rope, which has been said above to proceed from been made with the above views, was undertaken by the balloon, passed through the hole in the truck in Mr. Robertson and Lhoest, from Hamburgh, about the the centre of the parachute, and also through certain middle of July, 1803. The ascent having been actin tubes which were placed one after the other in the complished, the aëronauts hovered for some time over place of the handle or stick of an umbrella, and was the city; when, after throwing out some ballast, they lastly fastened to the basket; so that when the balloon rose to such a height, that the elasticity of the air diswas in the air, by cutting the end of this rope next to tended the balloon so much that they were under the nethe basket, the latter, with the attached parachute, cessity of opening the valve and suffering some of the would be separated from the balloon, and in falling gas to escape, which issued from its confinement with downwards, would naturally be opened by the resistance a loud noise. The tension of the balloon being thus of the air. The use of the tin tubes was, to let the rope considerably lessened, they threw ont more ballast, and slip off with greater certainty, and to prevent its becom- ascended to such a height, that it was almost imposing entangled with any of the other cordage, as also sible to endure the cold that they experienced. Their to keep the parachute at a distance from the basket. teeth chattered, and Mr. Robertson's veins swelled, The above description will be better understood by re and the blood issued from his nose. His companion ferring to the Plate, in which the ascent and descent of was otherwise affected, his head having swelled so M. Garnerin are shown in corresponding figures. The much that he could not keep on his hat; they also both balloon began to be filled abont two o'clock; there experienced a great numbness, which inclined them to were thirty-six casks filled with iron filings and diluted sleep. Not being able any longer to endure this temsulphuric acid, for the production of the hydrogen gas; perature, they descended slowly for about half an hour, these communicated with three other casks, or general and approached the earth over Badenburg, near Winreceivers, to each of which was fixed a pipe that sen on the Lube, where they intended to have alighted, emptied itself into the main tube attached to the but the inhabitants taking them for spectres fled with