AERONAUTICS HISTORY OF AEROSTATICS The history of aerostatics in the Middle Ages, like that of every other subject relating even remotely to science or knowledge of any kind, is little better than a record of the a falsehoods or chimeras circulated by impostors or enthusiasts. Truth was completely obscured by ignorance and fanaticism, and every person of superior talents and acquiremeats was believed to deal in magic, and to perform his feats of skill chiefly through the secret aid granted him by the prince of darkness; and in a later and comparatively recent period, those wretched creatures whom the unfeeling credulity of our ancestors, particularly during the prevalence of religious fanaticism, stigmatised and murdered under the denomination of witches, were supposed to work all their enchantments, to change their shapes at will, and to transport themselves through the air with the swiftness of thought, by a power derived from their infernal master, to whom was thus assigned the privilege of conferring the gift of aerial navigation upon his servants.

During the darkness of the Middle Ages every one at all distinguished for his knowledge in physics was generally reputed to have obtained the power of flying in the air. Friar Bacon did not scruple to claim the invention; and the credulity and indulgent admiration of some authors have lent to these pretensions more credit than they really deserved. Any one who takes the trouble to examine the passages of Bacon's obscure and ponderous works will find that the propositions advanced by him are seldom founded on reality, but ought rather to be considered as the illusions of a lively fancy. Albertus Magnus, who flourished in the first half of the 13th century, was reputed to have discovered the art; and to give an idea of the state of the physical sciences at that time, it is worth while to quote the following recipes from his De Mirabilibus Naturce: - " Take one pound of sulphur, two pounds of willow-carbon, six pounds of rock-salt ground very fine in a marble mortar; place, when you please, in a covering made of flying papyrus to produce thunder. The covering, in order to ascend and float away, should be long, graceful, well filled with this fine powder; but to produce thunder, the covering should be short, thick, and half full." (Quoted in Astra Castra, p. 25.) Regiomontanus, the first real mathematician after the partial revival of learning, is said, like Archytas, to have formed an artificial dove, which flew before the Emperor Charles V. at his public entry into Nuremberg; but the date of Regiomontanus' death shows this to have been impossible.

Attempts at flying have, as a rule, been made by a somewhat low class of projectors, who have generally united some little share of ingenuity to a smattering of mechanics. At the beginning of the 16th century an Italian alchemist visited Scotland, and was collated by James IV. to the abbacy of Tungland, in Galloway. Having constructed a set of wings, composed of various plumage, he undertook from the walls of Stirling Castle to fly through the air to France. This feat he actually attempted, but he soon came to the ground, and broke his thigh-bone by the violence of the fall - an accident he explained by asserting that the feathers of some fowls were employed in his wings, and that these had an affinity for the dunghill, whereas, if composed solely of eagles' feathers, they would have been attracted to the air. This anecdote has furnished to Dunbar, the Scottish poet, the subject of one of his rude satires. In 1617, Fleyder, rector of the grammar school at Tubingen, delivered a lecture on flying, which he published eleven years afterwards. A poor monk, however, ambitious to reduce the theory to practice, provided himself with wings; but his machinery broke down, and falling to the ground, he broke his legs and perished. Bishop Wilkins (4fathemat-ical 3fagick,.1648) says it was related that "a certain English monk called Elmerus, about the Confessor's time," flew by means of wings from a tower a distance of more than a furlong; that another person flew from St Mark's steeple at Venice; and another, at Nuremberg. He also quotes Busbequius to the effect that a Turk also attempted something of the kind at Constantinople. It would probably not be very difficult to make a long list of such narrations, in some of which the experimenter is related to have been successful, and in others to have failed; but the evidence is in no case very good, and we may feel certain that all the traditions of attempts with a successful issue are false.

In Borelli's posthumous work, De Motu Animatium, published at Rome in 1680-81, he calculated the enormous strength of the pectoral muscles in birds; and his proposition cciv. (vol. i. pp. 322-326) is entitled "Est impossibile, ut homines propriis viribus artificiose volare possint," in which he clearly points out the impossibility of man being able by his muscular strength to give motion to wings of sufficient extent to keep him suspended in the air. But Borelli did not, of course, as has sometimes been stated, demonstrate the impossibility of man's flying otherwise than merely by moans of his own muscular power.

A very slight consideration of the matter shows that, although the muscles of man may not be of sufficient strength to enable him to use wings, this objection does not apply against the possibility of making a flying chariot in which the motive power should be produced mechanically as in a watch, or a boat to float in the atmosphere. Both these projects have therefore always engaged the attention of abler men than has the art of flying, and it was only the ignorance of the nature and force of the atmosphere, as well as of the properties of all aeriform bodies, that caused so long a time to elapse before the invention of the balloon.

Albert of Saxony, a monk of the order of St Augustine, and a commentator on the physical works of Aristotle, seems first to have comprehended (though in a very vague and erroneous manner) the principles on which a body might be made to float in the atmosphere. Adopting, of course, Aristotelian views with regard to the nature of the elements, he considered that, as fire is more attenuated, and floats above our atmosphere, therefore a small portion of this ethereal substance, enclosed in a light hollow globe, would raise it to a certain height and keep it suspended in the air; and that, if more air were introduced, the globe would sink like a ship when water enters by a leak. Long afterwards Francis Mendoza, a Portuguese Jesuit, who died in 1626, at the age of forty-six, embraced this theory, and he held that the combustible nature of fire was no real obstacle, as its extreme levity and the extension of the air would prevent it from supporting inflammation. Casper Schott, also a Jesuit, adopted the same spcculation, only that he replaced the fire by the thin ethereal substance which he believed floated above our atmosphere; but, of eourse, the difficulty of procuring any of this ether was a sufficient obstacle.

Similar notions have been revived at different times. They were likewise often blended with the alchemical tenets so generally received in the course of the 15th, 16th, and part of the 17th centuries. Thus Schott quotes Lauretus Laurus to the effect that if swans' eggs or leather balls be filled with nitre, sulphur, or quicksilver, and be exposed to the sun, they will ascend. It was also believed that dew was of celestial origin, being shed by the stars, and that it was drawn up again in the course of the day to heaven by the heat of the sun. Thus Laurus states that hens' eggs filled with dew and exposed to the solar heat will rise. He was so grossly ignorant, however, of the principles of motion, that it is not worth while even to allude to his other assertions.

Cyrano de Bergerac (born 1620) wrote a philosophical romance entitled Histeire Comique des Estats et Empire de la Lune, and Les Estats et Empire du (from which Swift is supposed to have derived the idea of writing portions of Gulliver's Travels). To equip himself for performing the journey to the moon, the French traveller fastens round his body a multitude of very thin flasks filled with the morning's dew; the heat of the sun, by its attractive power on the dew, raised him up to the middle region of the atmosphere, whence, some of the flasks being broken, the adventurer sank again to the ground. Other aeronautical ideas occur in the romance.

Cardan proposed that ascensional power might be applied as in a rocket; and one Honoratus Fabry has described a huge apparatus, consisting of long tin pipes, worked by air coin pressed by the action of fire.

The most noted scheme for navinting the air promul gated previously to the successful experiments of the Montgolfiers, is due to a Jesuit, Francis Lana, and was proposed by him in a work entitled PrOd o o dell'Arte Maestro, Brescia, 1670. His idea, though useless and unpractical in so far that it could never be carried out is yet deserving of notice, as the principles involved are sound; and this can be said of no earlier attempt. His project was to procure four copper balls

So late as 1755, and not long before the invention of balloons, a very fanciful scheme was proposed by Joseph Galion. a Dominican friar. and 1 rofessor of philosophy and theology in the papal university of Avignon. This visionary proposed to collect the diffuse air of the upper regions, and to enclose it in a huge vessel extending more than a mile every way, and intended to carry fifty-four times as much weight as did Noah's ark. It is unnecessary to notice at greater length this absurd chimera, whick is merely mentioned here at all because it is sometimes referred to, though only on account of the magnitude of the fantastic scheme.

It is proper here to remark, that nearly all the early projectors imagined that the atmosphere was of no great height, and that it covered the earth like a shallow ocean, having a well-defined boundary ; and the aerial vessels which they proposed were intended to float on the surface of this ocean, exactly as ships do on the sea, with their upper portions in the ether or diffuse air, or whatever the fluid might be, that lay above. And these ideas were, of course, not dispelled till after the invention of the barometer and the discovery of the law of the decrease of atmospheric pressure with elevation.

Some writers have stated that Francis Bacon first published the true principles of aeronautics. This assertion we cannot help noticing, because it has really no foundation except in the propensity, fostered by indolence, which would gladly refer all the discoveries ever made to a few great names. They mistake, indeed, the character of Bacon who seek to represent him as an inventor. His claim to immortality rests chiefly on the profound and comprehensive views which he took of the bearings of the different parts of human knowlege; for it would be difficult to point out a single fact or observation with which he enriched the store of physical science. On the contrary, being very deficient in mathematical learning, he disregarded or rejected some of the noblest discoveries made in his ow n time.

We can find only two passages in Bacon's works which can be considered as referring to aeronautics, and they both occur in that collection of loose facts and inconclusive reasonings which he has entitled Xatural History. The first is styled Experiment Solitary, touching Flying in the Air, and runs thus - " Certainly many birds of good wing (as kites and the like) would bear up a good weight as they fly; and spreading feathers thin and close, and in great breadth, will likewise bear up a great weight, being even laid, without tilting up on the sides. The farther extension of this experiment might be thought upon." The second passage is more diffuse, but less intelligible; it is styled Experiment Solitary, touching the Flying of unequal Bodies in the Air: - " Let there be a body of unequal weight (as of wool and lead or bone and lead); if you throw it from you with the light end forward, it will turn, and the weightier end will recover to be forwards, unless the body be over long. The cause is, for that the more dense body bathe more violent pressure of the parts from the first impulsion, which is the cause (though heretofore not found out, as hath been often said) of all violent motions; and when the hinder part moveth swifter (for that it less endureth pressure of parts) than the forward part can make way for it, it must needs be that the body turn over; for (turned) it can more easily draw forward the lighter part." The fact here alluded to is the resistance that bodies experience in moving through the air, which, depending on the quantity of surface merely, must exert a proportionally greater effect on rare substances. The passage itself, however, after making every allowance for the period in which it was written, must be deemed confused, obscure, and unphilosophical.

We now come to the discovery of the balloon, which was due to Stephen and Joseph Montgolficr, sons of Peter Montgolfier, a large and celebrated papermaker at Annonay, a town about tO miles from Lyons. The brothers had observed the suspension of clouds in the atmosphere, and it occurred to them that if they could enclose any vapour of the nature of a cloud in a large and very light bag, it might rise and carry the bag mith it into the air. They accordingly made experiments, inflating bags with smoke from a fire placed underneath, and found either that the smoke or some vapour emitted from the fire did ascend and carry the bag with it. Being thus assured of the correctness of their views, they determined to have a public ascent of a balloon on a large scale. They accordingly invited the States of Vivarais, then assembled at Annonay, to witness their aerostatic experiment; and on June 5, 1783, in the presence of a considerable concourse of spectators, a linen globe of 105 feet in circumference was inflated over a fire fed with small bundles of chopped straw, and when released rapidly rose to a great height, and descended, at the expiration of ten minutes, at the distance of about 1i mile. This was the discovery of the balloon. The brothers Montgolfier imagined that the bag rose because of the levity of the smoke or other vapour given forth by the burning straw; and it was not till some time later that it was recognised that the ascending power was due merely to the lightness of heated air compared to an equal volume of air at a lower temperature. Air, like all other fluids, expands by heat, and thereby becomes.rarefied, so that any volume of hot air weighs less than the corresponding volume of air at a lower temperature. If, then, the air inside the balloon be so heated that it., together with the balloon, weighs less than the air displaced, the balloon will rise till it arrives at such a height that it and the enclosed air are equal in weight to that of fhe displaced air, when equilibrium will be obtained. In Montgolfier's first balloon, no source of heat was taken up with it, so that the air inside rapidly cooled, and the balloon soon descended.

The news of the experiment at Annonay rapidly spread over Europe, and at Paris attracted so much attention that M. Faujas de Saint-Fond, a naturalist, set on foot a subscription for paying the expense of repeating the experiment. The balloon was constructed by two brothers of the name of Robert, under the superintendence of M. Charles, professor of natural philosophy in Paris, and afterwards a member of the Academy of Sciences. It had at first been suggested to copy the process of Montgolfier, but Charles proposed the application of hydrogen gas, which was adopted. The filling of the balloon, which was made of thin silk varnished with a solution of elastic gum, and was about 13 feet in diameter, was commenced on August 23, 1783, in the Place des Victoires. The hydrogen gas was obtained by the action of dilute sulphuric acid upon iron filings, and was introduced through leaden pipes; but as the gas was not passed through cold water, great difficulty was experienced in filling the balloon completely; and altogether about 500 lb of sulphuric acid and twice that amount of iron filings were used. Bulletins were issued daily of the progress of the inflation; and the crowd was so great that on the 26th the balloon was moved to the Champ de Mars, a distance of 2 miles. This was done secretly, in the middle of the night., to avoid the crowd; and the appearance of the balloon being thus removed, preceded by lighted torches and escorted by a detachment of soldiers, is described as having been very remarkable. On the next day, August 27, an Immense concourse of people covered the Champ de Mars, and every spot from which a view could be obtained was crowded. About five o'clock a cannon was discharged as the signal for the ascent, and the balloon when liberated rose to the height of about 3000 feet with great rapidity. A shower of rain which began to fall directly after the balloon had left the earth in no way checked its progress; and the excitement was so great, that thousands of well-dressed spectators, many of them ladies, stood exposed, watching it intently the whole time it was in sight, and were drenched to the skin. The balloon, after remaining in the air for about three. quarters of an hour, fell in a field near Gonesse, about 15 miles off, and terrified the peasantry so much that it was torn into shreds by them. Hydrogen gas was at this time known by the name of inflammable air; and balloons inflated with gas have ever since been called by the people air-balloons, the kind invented by the Montgolfiers being designated fire-balloons. French writers have also very frequently styled them after their inventors, CharNres and Montgolfieres.

On the 19th of September 1783 Joseph Montgolfier repeated the Annonay experiment at Versailles, in the presence of the king, the queen, the court, and an immense number of spectators. The inflation was commenced at one o'clock, and completed in eleven minutes, when the balloon rose to the height of about 1500 feet, and descended after eight minutes, at a distance of about two miles, in the wood of Vaucresson. Suspended below the balloon, in a cage, had been placed a sheep, a cock, and a duck, which were thus the first aerial travellers. They were quite uninjured, except the cock, which had its right wing hurt in consequence of a kick it had received from the sheep; but this took place before the ascent. The balloon, which was painted with ornaments in oil colours, had a very showy appearance.

The first human being who ascended in a balloon was M. Francois Pilftre de Rozier, a young naturalist, who, two years afterwards, was killed in an attempt to cross the English Channel in a balloon. On October 15, 1783, and following days, he made several ascents (generally alone, but once with a companion, M. Girond de Villette), in a captive balloon (i.e., one attached by ropes to the ground), and demonstrated that there was no difficulty in taking up fuel and feeding the fire, which was kindled in a brazier suspended under the balloon, when in the air. The way being thus prepared for aerial navigation, on November 21, 1783, M. Pilittre de Rozier and the Marquis d'Arlandes first trusted themselves to a free fire-balloon. The experiment was made from the Jardin du Chateau de la Muette, in the Bois de Boulogne. The machine employed, which was a large fire-balloon, Was inflated at about two o'clock, and leaving the earth at this time, it rose to a height of about 500 feet, and passing over the Invalides and the Ecole Militaire, descended beyond the Boulevards, about 9000 yards from the place of ascent, having been between twenty and twenty-five minutes in the air. The result was completely successful; and it is scarcely necessary to add, the excitement in Paris was very great.

Only ten days later, viz., on December 1, 1783, MM. Charles and Robert ascended from Paris in a balloon in-flitted with hydrogen gas. The balloon, as in the case of the small one of the sane kind previously launched from the Champ de Mars, was constructed by the brothers Robert. It was 27 feet in diameter, and the car was suspended from a hoop surrounding the middle of the balloon, and fastened to a net which covered the upper hemisphere. The balloon ascended very gently from the Tuileries at a quarter to two o'clock, and after remaining for some time at an elevation of about 2000 feet, it descended in about two hours at Nesle, a small town about 27 miles from Paris, when M. Robert left the car, and M. Charles made a second ascent by himself. He had intended to have replaced the weight of his companion by a nearly equivalent quantity of ballast; but nut having any suitable means of obtaining such ready at the place of descent, and it being just upon sunset, he gave the word to let go, and the balloon being thus so greatly lightened, ascended very rapidly t.o a height of about 2 miles. After staying in the air about half-an-hour, he descended 3 miles from the place of ascent, although he believed the distance traversed, owing to different currents, to have been about 9 miles. In this second journey M. Charles experienced a violent pain in his right ear and jaw, no doubt produced by the rapidity of the ascent. He also witnessed the phenomenon of a double sunset on the same day ; fur when he ascended, the sun had set in the valleys, and as he mounted he saw it rise again, and set a second time as he descended.

All the features of the modern balloon as now used are inure or less due to Charles, who invented the valve at the top, suspended the car from a hoop, which was itself attached to the balloon by netting, If:e. The M. Robert who accompanied him in the ascent was one of the brothers who had constructed it..

On January 19, 1784, the largest balloon on record (if the contemporary accounts are correct) ascended from Lyons. It was more than 100 feet in diameter, about 130 feet in height, and when distended had a capacity, it is said, of over half-a-million cubic feet. It was called the Plesselles (from the name of its proprietor or owner, we believe), and after having been inflated from a straw fire in seventeen minutes, it rose with seven persons in the car, viz., Joseph Montgolfier, Pillitre de Rozier, Count de Laurencin, Count de Da.mpierre, Prince Charles de Ligne, Count de Laport cl'Anglefort, and M. Fontaine, the last gentleman having leaped into the car just as the machine had started. The fire was fed with trusses of straw, and the balloon rose majestically t.o the height of about 3000 feet, but descended again after the lapse of about a quarter of an hoar from the time of starting, in consequence of a rent in the upper part.

It is proper here to state that researches on the use of gas for inflating balloons seem to have been carried on at Philadelphia nearly simultaneously with the experiments of the Montgolfiers ; and when the news of the latter reached America, Messrs Rittenhouse and Hopkins, members of the Philosophical Academy of Philadelphia, constructed a machine consisting of forty-seven small hydrogen gas-balloons attached to a car or cage. After several preliminary- experiments, in which animals were let up to a certain height by a rope, a carpenter, one James Wilcox, was induced to enter the car for a small sum of money ; the ropes were cut, and lie remained in the air about ten minutes, and only then effected his descent by making incisions in a number of the balloons, through fear of falling into the river, which he was approaching.

The improvements that have been made in the management and inflation of balloons in the last ninety years have only had reference to details, so that as far as essential principles are concerned the subject is now in pretty much the same state as it was in 1783. We have therefore arrived at a point in the history of the balloon where it is well to consider how much the Montgolfiers and Charles owed to their predecessors ; and it is proper here to state that, although we have assigned the invention to the two brothers, Stephen and Joseph - as no doubt they both conducted the early experiments together - still there is reason to believe that the share of the latter was very small. Stephen, however, although the originator of balloons, does not appear ever to have ascended himself, and Joseph did not repeat the ascent just mentioned in the Flesselles. The Montgolfiers had studied Priestley's Experiments relating to different kinds of Air, whence they first conceived the possibility of navigating the atmosphere; but their experiment was so simple as to require scarcely any philosophical knowledge. They had seen smoke ascend, and thought that if they could imprison it in a bag, the bag might ascend too ; and the observation and reasoning were both such as might occur to anybody. This does not detract from their merit; it, on the contrary, adds to it. The fact that millions of persons must have observed the same thing, and had not derived anything practical therefrom, only enhances the glory of those who in such well-worn tracts did make a discovery; but the simplicity of the invention shows that it is needless to inquire whence the brothers were led to make it, and how far any part of the credit is due to their predecessors. It is scarcely possible to imagine anything more remarkable than that the fact that a light bag held over a fire would ascend into the air was not discovered till 1783, notwithstanding that men in all ages had seen smoke ascend from fire (though, of course, the fire-balloon does not ascend for exactly the same reason that smoke does). It might be supposed that the connection of the Montgolfiers with a paper manufactory gave them facilities for constructing their experimental balloons of thin paper ; and perhaps such was the case, although we can find no evidence of it. With regard to Charles's substitution of hydrogen gas, there are anticipations that must be noticed. As early as 1766 Cavendish showed that this gas was at least seven times lighter than ordinary air, and it immediately occurred to Dr Black, of Edinburgh, well known as the discoverer of latent heat, that a thin bag filled with hydrogen gas would rise to the ceiling of a room. He provided, accordingly, the allantois of a calf, with the view of showing at a public lecture such a curious experiment; but for some reason it seems to have failed, and Black did not repeat it, thus allowing a great discovery, almost within his reach, to escape him. Several years afterwards a similar idea occurred to Tiberius Cavallo, who found that bladders, even when carefully scraped, are too heavy, and that China paper is permeable to the gas. But in 1782, the year before the invention of the Montgolfiers, he succeeded in elevating soap-bubbles by inflating them with hydrogen gas. The discovery of fire-balloons might have taken place almost at any time in the world's history, but the substitution of hydrogen gas for heated air could not have been made previously to the latter half of the last century; and although all the honour of an independent discovery belongs to the Montgolfiers, Charles, by his substitution of "inflammable air" for heated air, merely showed himself acquainted with the state of chemical science of his day. Charles never again ascended after his double expedition on the 1st of December 1783.

We now return to the history of aerial navigation, and commence with an account of the first ascents of balloons in this country. Although the news of the Annonay and subsequent experiments in France rapidly spread all over Europe, and formed a topic of general discussion, still it was not till five months after the Montgolfiers had first publicly sent a balloon into the air that any aerostatic experiment was made in England. In November 1783 Count Zambeccari, an Italian, who happened to be in London, made a balloon of oil-silk, 10 feet in diameter, and weighing 11 lb. It was publicly shown for several clays, and on the 25th it was three-quarters filled with hydrogen gas, and launched from the Artillery ground at one o'clock. It descended after two hours and a half near Petworth, in Sussex, 48 miles from London. This was the first balloon that ascended from English ground. On February 22, 1784, a hydrogen gas balloon, 5 feet in diameter, was let up from Sandwich, in Kent, and descended at Warneton, in French Flanders, 75 miles distance. This was the first balloon that crossed the Channel. The difficulties and dangers of aerial navigation having been surmounted by the end of the year The Chevalier Paul Andreani, of Milan, constructed a fire-balloon 68 feet in diameter, and on February 25, 1784, ascended from Milan with two- brothers of the name of Gerli, and remained in the air for about twenty minutes. This is usually regarded as the first ascent in Italy (but see Monck Mason's Aeronautica, p. 247). Andreani ascended again on March 13, with two other persons.

On the 2d of March M. Jean Pierre Blanchard, who had been for some years before occupied with projects for flying, made his first voyage from Paris in a balloon 27 feet in diameter, and descended at Billaneourt, near Sevres. Just as the balloon was about to ascend, a young man jumped into the car, and, drawing his sword, declared his determination to ascend with Blanchard. He was ultimately removed by force. The episode is worth noting, as it has sometimes been stated that the young man was Napoleon Bonaparte, but this is untrue ; his name was Dupont de Chambon. Blanchard made subsequently, it is said, more than thirty aerial voyages, and he is one of the most celebrated of the earlier aeronauts. Ile also crossed the English Channel, as noticed further on.

On July 15, 1784, the Due de Chartres and the two brothers Robert ascended from St Cloud; but the neck of the balloon becoming choked up with an interior balloon filled with common air, intended to regulate the ascending and descending power, they were obliged to make a hole in the balloon, in order to allow of the escape of the gas, but they descended in safety.