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atmospheric pressure occur in springs in various parts of the or myths of men or animals which are supposed to have travelled world (see MINERAL WATERS). Such waters, which also generally through the air, such as Pegasus, Medea's dragons and Daedalus, hold in solution a considerable percentage of saline constituents, as well as in Egyptian bas-reliefs, wings appear as the means by early acquired a reputation as medicinal agents, and when carbon which aerial locomotion is effected. In later times there are dioxide ("fixed air ") became familiar to chemists the possibility many stories of men who have attempted to fly in the same way. was recognized, as by Joseph Priestley (Directions for impregnat- John Wilkins (1614-1672), one of the founders of the Royal ing water with fixed air . . . to communicate the peculiar Spirit Society and bishop of Chester, who in 1640 discussed the possiand Virtues of Pyrmont water,1772), of imitating them artificially.bility of reaching the moon by volitation, says in his MatheMany of the ordinary aerated waters of commerce, however, do matical Magick (1648) that it was related that " a certain English not pretend to reproduce any known natural water; they are monk called Elmerus, about the Confessor's time," flew from a merely beverages owing their popularity to their effervescing town in Spain for a distance of more than a furlong; and that properties and the flavour imparted by a small quantity of some other persons had flown from St Mark's, Venice, and at Nuremsalt such as sodium bicarbonate or a little fruit syrup. Their berg. Giovanni Battista Dante, of Perugia, is said to have flown manufacture on a considerable scale was begun at Geneva so several times across Lake Trasimene. At the beginning of the far back as 1790 by Nicholas Paul, and the excellence of the 16th century an Italian alchemist who was collated to the abbacy soda water prepared in London by J. Schweppe, who had been of Tungland, in Galloway, Scotland, by James IV., undertook a partner of Paul's, is referred to by Tiberius Cavallo in his to fly from the walls of Stirling Castle through the air to France. Essay on the Medicinal Properties of Factitious Airs, published in❘ He actually attempted the feat, but soon came to the ground 1798. Many forms of apparatus are employed for charging the and broke his thigh-bone in the fall-an accident which he exwater with the gas. A simple machine for domestic use, called a plained by asserting that the wings he employed contained some gasogene or seltzogene, consists of two strong glass globes con- fowls' feathers, which had an "affinity" for the dung-hill, whereas nected one above the other by a wide glass tube which rises if they had been composed solely of eagles' feathers they would nearly to the top of the upper and smaller globe. Surmounting have been attracted to the air. This anecdote furnished Dunbar, the small globe there is a spring valve, fitted to a narrow tube the Scottish poet, with the subject of one of his rude satires. that passes through the wide tube to the bottom of the large Leonardo da Vinci about the same time approached the problem globe. To use the machine, the lower vessel is filled with water, in a more scientific spirit, and his notebooks contain several and in the upper one, round the base of the wide tube, is placed a sketches of wings to be fitted to the arms and legs. In the mixture, commonly of sodium bicarbonate and tartaric acid, following century a lecture on flying delivered in 1617 by which with water yields carbon dioxide. The valve head is Fleyder, rector of the grammar school at Tübingen, and pubthen fastened on, and by tilting the apparatus some water is lished eleven years later, incited a poor monk to attempt to put made to flow through the wide tube from the lower to the upper the theory into practice, but his machinery broke down and he vessel. The water in the lower globe takes up the gas thus was killed. produced, and when required for use is withdrawn by the valve, being forced up the narrow tube by the pressure of the gas. In another arrangement the gas is supplied compressed in little steel capsules, and is liberated into a bottle containing the water which has to be aerated. On a large scale, use is made of continuously acting machinery which is essentially of the type devised by Joseph Bramah. The gas is prepared in a separate generator by the action of sulphuric acid on sodium bicarbonate or whiting, and after being washed is collected in a gas-holder, whence it is forced with water under pressure into a receiver or saturator in which an agitator is kept moving. Some manufacturers buy their gas compressed in steel cylinders. The water thus aerated or carbonated passes from the receiver, in which the pressure may be 100-200 lb on the square inch, to bottling machines which fill and close the bottles; if beverages like lemonade are being made the requisite quantity of fruit syrup is also injected into the bottles, though sometimes the fruit syrup mixture is aerated in bulk. For soda water sodium bicarbonate should be added to the water before aeration, in varying proportions up to about 15 grains per pint, but the simple carbonated water often does duty instead. Potash water, lithia water and many others are similarly prepared, the various salts being used in such amounts as are dictated by the experience and taste of the manufacturer. Aerated waters are sent out from the factories either in siphons (q.v.) or in bottles; the latter may be closed by corks, or by screw-stoppers or by internal stoppers consisting of a valve, such as a glass ball, held up against an indiarubber ring in the neck by the pressure of the gas. For use in soda-fountains the waters are sent out in large cylinders.

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See W. Kirkby, Evolution of Artificial Mineral Waters (Manchester, 1902). AERONAUTICS, the art of "navigating" the "air." It is divisible into two main branches-aerostation, dealing properly with machines which like balloons are lighter than the air, and aviation, dealing with the problem of artificial flight by means of flying machines which, like birds, are heavier than the air, and also with attempts to fly made by human beings by the aid of artificial wings fitted to their limbs.

Historically, aviation is the older of the two, and in the legends

In Francis Bacon's Natural History there are two passages which refer to flying, though they scarcely bear out the assertion made by some writers that he first published the true principles of aeronautics.

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The first is styled Experiment Solitary, touching Flying in the Air: Certainly many birds of good wing (as kites and the like) would close, and in great breadth, will likewise bear up a great weight, being bear up a good weight as they fly; and spreading feathers thin and 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 hath a more violent pressure heretofore not found out, as hath been often said) of all violent of the parts from the first impulsion, which is the cause (though 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.

In his posthumous work, De Motu Animalium, published at Rome in 1680-1681,G.A. Borelli gave calculations of the enormous strength of the pectoral muscles in birds; and his proposition cciv. (vol. i. pp. 322-326), entitled Est impossibile ut homines propriis viribus artificiose volare possint, 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 during his lifetime two Frenchmen, Allard in 1660 and Besnier about 1678, are said to have succeeded in making short flights. An account of some of the modern attempts to construct flying machines will be found in the article FLIGHT AND FLYING; here we append a brief consideration of the mechanical aspects of the problem.

The very first essential for success is safety, which will probably is that the centre of gravity shall at all times be on the same vertical only be attained with automatic stability. The underlying principle line as the centre of pressure. The latter varies with the angle of incidence. For square planes it moves approximately as expressed

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by joessel's formula, C+ (0.2+0.3 sin a) L, in which C is the distance from the front edge, L the length fore and aft, and a the angle of incidence. The movement is different on concave surfaces. The term aeroplane is understood to apply to flat sustaining surfaces, but experiment indicates that arched surfaces are more efficient. S. P. Langley proposed the word aerodrome, which seems the preferable term for apparatus with wing-like surfaces. This is the type to which results point as the proper one for further experiments. With this it seems probable that, with well-designed apparatus, 40 to 50 lb can be sustained per indicated h.p., or about twice that quantity per resistance or thrust h.p., and that some 30 or 40% of the weight can be devoted to the machinery, thus requiring motors, with their propellers, shafting, supplies, &c., weighing less than 20 lb per h.p. It is evident that the apparatus must be designed to be as light as possible, and also to reduce to a minimum all resistances to propulsion. This being kept in view, the strength and consequent section required for each member may be calculated by the methods employed in proportioning bridges, with the difference that the support (from air pressure) will be considered as uniformly distributed, and the load as concentrated at one or more points. Smaller factors of safety may also have to be used. Knowing the sections required and unit weights of the materials to be employed, the weight of each part can be computed. If a model has been made to absolutely exact scale, the weight of the full-sized apparatus may approximately be ascertained by the formula

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in which W is the weight of the model, S its surface, and W' and S'
the weight and surface of the intended apparatus. Thus if the model
has been made one-quarter size in its homologous dimensions, the
supporting surfaces will be sixteen times, and the total weight sixty-
four times those of the model. The weight and the surface being
determined, the three most important things to know are the angle
of incidence, the "lift," and the required speed. The fundamental
formula for rectangular air pressure is well known: P=KV'S, in
which P is the rectangular normal pressure, in pounds or kilograms,
K a coefficient (0.0049 for British, and 0.11 for metric measures),
V the velocity in miles per hour or in metres per second, and S the
surface in square feet or in square metres. The normal on oblique
surfaces, at various angles of incidence, is given by the formula
P KV2Sn, which latter factor is given both for planes and for arched
surfaces in the subjoined table:-

PERCENTAGES OF AIR PRESSURE AT VARIOUS ANGLES
OF INCIDENCE

Planes (Duchemin For

MULA, VERIFIED by Langley).

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and therefore to be negative to the relative wind. Former modes of computation indicated angles of 10° to 15° as necessary for support with planes. These were prohibitory in consequence of the great drift"; but the present data indicate that, with concave surfaces, angles of 2° to 5° will produce adequate "lift." To compute the latter the angle at which the wings are to be set must first be assumed, and that of +3° will generally be found preferable. Then the required velocity is next to be computed by the formula V=

or for concave wings at +3°:

=

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L
KSηcosa'

W 0.545KS

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Having thus determined the weight, the surface, the angle of inci-
dence and the required speed for horizontal support, the next step
is to calculate the power required. This is best accomplished by first
obtaining the total resistances, which consist of the "drift" and of
the head resistances due to the hull and framing. The latter are
arrived at preferably by making a tabular statement showing all
the spars and parts offering head resistance, and applying to each
the coefficient appropriate to its master section," as ascertained by
experiment. Thus is obtained an equivalent area" of resistance,
which is to be multiplied by the wind pressure due to the speed. Care
must be taken to resolve all the resistances at their proper angle of
application, and to subtract or add the tangential force, which con-
sists in the surface S, multiplied by the wind pressure, and by the
factor in the table, which is, however, o for 3° and 32°, but positive
or negative at other angles. When the aggregate resistances are
known, the "thrust h.p." required is obtained by multiplying the
resistance by the speed, and then allowing for mechanical losses in
indicated h.p. Close approximations are obtained by the above
the motor and propeller, which losses will generally be 50% of
method when applied to full-sized apparatus. The following example
will make the process clearer. The weight to be carried by an appar-
atus was 189 lb on concave wings of 143.5 sq. ft. area, set at a positive
angle of 3°. There were in addition rear wings of 29.5 sq. ft., set at
a negative angle of 3°; hence, L=189=0·005 XV2X143.5X0.545.
Whence V = 0.005X143-5X0-545
=22 miles per hour,

189

at which the air pressure would be 2.42 lb per sq. ft. The area of spars and man was 17.86 sq. ft., reduced by various coefficients to an equivalent surface "of 11.70 sq. ft., so that the resistances

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2sina

WINGS (LILIENTHAL),
Concavity I in 12.

N=P

I+sin a

Total resistance

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=0.00

=28.31

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+0.070 0.040 0.0396 | -0.0055 +0.067 0.080 0-0741-0-0097 +0.064 0.120 0.1193 -0.0125 +0.060 0.160 0.1594 -0.0139 +0.055 0.200 0.1995-0.0139 +0.049 0.242 0.2416 -0.0126 +0.043

40-38X22 =2.36 h.p. for the 375 or 4.72 h.p. for the motor. The weight being 189 lb, and

40.38 = 189

the resistance 40.38 lb, the gliding angle of descent was
tangent of 12°, which was verified by many experiments.
The following expressions will be found useful in computing such
projects, with the aid of the table above given:-
1. Wind force, F = KV2.
2. Pressure, P= KV2S.

0.286 0.2858 -0.0100 +0.037 3. Velocity, V=W

0.332 0.3318 -0.0058 +0.031 0.381 0.3810 -0.0 +0.024 0.035 0.035 0.000611 0.434 0.434 +0.0075 +0.016 0.070 0.070 0.00244 0.489 | 0.489 +0.0170 +0.008 0.104 0.104 0.00543 0.546 0.545 +0.0285 0.0 0.139 0.139 | 0·0097 0.600 0.597 +0.0418 -0.007 0.174 0.173 0.0152 0.650 0.647 +0.0566 -0.014 +6° 0.207 0.206 0.0217 0.696 0.692 +0.0727 -0.021 +70-240 0.238 0.0293 0.737 0.731 +0.0898 -0.028 +8° 0.273 0.270 0.0381 0.771 0.763 +0.1072 -0.035 +9° 0.305 0.300 0.0477 0-800 0.790 +0.1251 -0.042 10° 0.337 0.332 0.0585 0.825 0.812 +0.1432 -0.050 0.369 0.362 0.0702 0.846 0.830 +0.1614 -0.058 0.398 0.390 0.0828 0.864 0.845 +0.1803 -0.064 13 0.431 0.419 0.0971 0.879 0.856 +0.1976 -0.070 14 0.457 0.443 0.1155 0.891 0.864 +0.2156 -0.074 15° 0.486 0.468 0.1240 0.901 0.870 +0.2332 -0.076

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8. Drift, D= KSV2nsina.

9. Head area E, get an equiva-
lent.

10. Head resistance, H = EF.
II. Tangential force, T = Pa.
12. Resistance, R=D+H±T.
13. Ft. lb, M=RV.
RV
14. Thrust, h.p., factor

Aerostation. Possibly the flying dove of Archytas of Tarentum is the earliest suggestion of true aerostation. According to Aulus Gellius (Noctes Atticae) it was a "model of a dove or pigeon formed in wood and so contrived as by a certain mechanical art and power to fly: so nicely was it balanced by weights and put in motion by hidden and enclosed air." This "hidden and enclosed air" may conceivably represent an anticipation of the hot-air balloon, but it is at least as probable that the apparent flight of the dove was a mere mechanical trick depending on the use of fine wires or strings invisible to the spectators.

In the middle ages vague ideas appear of some ethereal substance so light that vessels containing it would remain suspended in the air. Roger Bacon (1214-1294) conceived of a large hollow globe made of very thin metal and filled with ethereal air or liquid fire, which would float on the atmosphere like a ship

Invention of the balloon.

on water. Albert of Saxony, who was bishop of Halberstadt | by attaching to each a tube 36 ft. long, fitted with a stopcock, from 1366 to 1390, had a similar notion, and considered that a and so producing a Torricellian vacuum, suggests that he was small portion of the principle of fire enclosed in a light sphere ignorant of the invention of the air-pump by Otto von Guericke would raise it and keep it suspended. The same speculation about 1650. was advanced by Francis Mendoza, a Portuguese Jesuit, who died in 1626 at the age of forty-six, and by Gaspar Schott (16081666), also a Jesuit and professor of mathematics at Würzburg, though for fire he substituted the thin ethereal fluid which he believed to float above the atmosphere. So late as 1755 Joseph Galien (1699-1782), a Dominican friar and professor of philosophy and theology in the papal university of Avignon, 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! A somewhat different but equally fantastic method of making heavy bodies rise is quoted by Schott from Lauretus Laurus, according to whom swans' eggs or leather balls filled with nitre, sulphur or mercury ascend when exposed to the sun. Laurus also stated that hens' eggs filled with dew will ascend in the same circumstances, because dew is shed by the stars and drawn up again to heaven by the sun's heat during the day. The same notion is utilized by Cyrano de Bergerac (1619-1655) in his romances describing journeys to the moon and sun, for his French traveller fastens round his body a multitude of very thin flasks filled with the morning's dew, whereby through the attractive power of the sun's heat on the dew he is raised to the middle regions of the atmosphere, to sink again, however, on the breaking of some of the flasks.

A distinct advance on Schott is marked by the scheme for aerial navigation proposed by the Jesuit, Francis Lana (16311687), in his book, published at Brescia in 1670, Prodromo ovvero Saggio di alcune invenzioni nuove promesso all' Arte Maestra. 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 of very large dimensions (fig. 1), yet so extremely thin that after the air was exhausted from them they would be lighter than the air they displaced and so would rise; and to those four balls he proposed to attach a boat, with sails, &c., which would carry up a man. He submitted the whole matter to calculation, and proposed that the globes should be about 25 ft. in diameter and 1th of an inch in thickness; this would give from all four balls a total ascensional force of about 1200 lb, which would be quite enough to raise the boat, sails, passengers, &c. But the obvious objection to the whole scheme is, that it would be quite impossible to construct a globe of so large a size and of such small thickness which would even support its own weight without collapsing if placed on the ground, much less bear the external atmospheric pressure when the internal air was removed. Lana himself noticed this objection, but he thought that the spherical form of the copper shell would, notwithstanding its extreme thinness, enable it, after the exhaustion was effected, to sustain the enormous pressure, which, acting equally on every point of the surface, would tend to consolidate rather than to break the metal. His proposal to exhaust the air from the globes

FIG. 1.-Lana's Aeronautical Machine.

We now come to the invention of the balloon, which was due to Joseph Michel Montgolfier (1740-1810) and Jacques Etienne Montgolfier (1745-1799), sons of Pierre Montgolfier, a large and celebrated papermaker at Annonay, a town about 40 m. 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 with it into the air. Towards the end of 1782 they inflated bags with smoke from a fire placed underneath, and found that either 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 the 5th of June 1783, in the presence of a considerable concourse of spectators, a linen globe of 105 ft. in circumference was inflated over a fire fed with small bundles of chopped straw. When released it rapidly rose to a great height, and descended, at the expiration of ten minutes, at the distance of about 1m. 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 recognized that the ascending power was due merely to the lightness of heated air compared to an equal volume of air at a lower temperature. In this balloon, no source of heat was taken up, so that the air inside rapidly cooled, and the balloon soon descended.

The news of the experiment at Annonay attracted so much attention at Paris that Barthélemi Faujas de Saint-Fond (17411819), afterwards professor of geology at the Musée d'Histoire Naturelle, 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 the physicist, J. A. C. Charles. The first suggestion was 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 ft. in diameter, was begun on the 23rd of August 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 (fig. 2). Bulletins were issued daily of the progress of the inflation; and the crowd was so great that on the 26th the balloon was moved secretly by night to the Champ de Mars, a distance of 2 m. On the next day 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 ft. with great rapidity. A shower of rain which began to fall directly after it 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

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FIG. 2.-Charles' and Robert's Balloon.

previously launched from the Champ de Mars, was constructed by the brothers Robert, one of whom took part in the ascent. It was 27 ft. 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 ft., it descended in about two hours at Nesle, a small town about 27 m. from Paris, when Robert left the car, and 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 not having any suitable means of obtaining such 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 to a height of about 2 m. After staying in the air about half an hour, he descended 3 m. from the place of ascent, although he believed the distance traversed, owing to different currents, to have been about 9 m. In this second journey he experienced a violent pain in his right ear and

were drenched to the skin. The balloon, after remaining in the | The balloon, as in the case of the small one of the same kind air for about three-quarters of an hour, fell in a field near Gonesse, about 15 m. 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, Charlières and Montgolfières. 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 begun at one o'clock, and completed in eleven minutes, when the balloon rose to the height of about 1500 ft., and descended after eight minutes, at a distance of about 2 m., 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 orna-jaw, no doubt produced by the rapidity of the ascent. He also ments in oil colours, had a very showy appearance (fig. 3).

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The first human being who ascended in a balloon was Jean François Pilâtre de Rozier (1756-1785), a native of Metz, who was appointed superintendent of the natural history collections of Louis XVIII. On the 15th of October 1783, and following days, he made several ascents (generally alone, but once with a companion, 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 the 21st of November 1783, Pilâtre de Rozier and the marquis d'Arlandes first trusted themselves to a free fire-balloon. The experiment was made from the Jardin du Château de la Muette, in the Bois de Boulogne. A large fire-balloon was inflated at about two o'clock, rose to a height of about 500 ft., and passing over the Invalides and the Ecole Militaire, descended beyond the Boulevards, about 9000 yds. from the place of ascent, having been between twenty and twenty-five minutes in the air.

Only ten days later, viz. on the 1st of December 1783, Charles ascended from Paris in a balloon inflated with hydrogen gas.

witnessed the phenomenon of a double sunset on the same day; for 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 more 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, &c. With regard to his use of hydrogen gas, there are anticipations that must be noticed. As early as 1766 Henry Cavendish showed that this gas was at least seven times lighter than ordinary air, and it immediately occurred to Dr. Joseph Black, of Edinburgh, 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.

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, D. Rittenhouse and F. Hopkinson, members of the Philosophical Society at 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 he 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.

[graphic]

Great

Britain.

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 First months after the Montgolfiers had first publicly sent ascents in a balloon into the air that any aerostatic experiment was made in England. In November 1783 Count Francesco Zambeccari (1756-1812), an Italian who happened to be in London, made a balloon of oil-silk, 10 ft. in diameter, and weighing 11 lb. It was publicly shown for several days, 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 m. from London. This was the first balloon that ascended from English ground. On the 22nd of February 1784 a hydrogen gas balloon, 5 ft. in diameter, was let up from Sandwich, in Kent, and descended at Warneton, in French Flanders,

75 m. distant. This was the first balloon that crossed the Channel. The first person who rose into the air from British ground appears to have been J. Tytler, who ascended from the Comely Gardens, Edinburgh, on the 27th of August 1784, in a fire-balloon of his own construction. He descended on the road to Restalrig, about half a mile from the place where he rose.

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came out to view the balloon. The king also was in conference with his ministers; but on hearing that the balloon was passing, he broke up the discussion, and with them watched the balloon through telescopes. The balloon was afterwards exhibited in the Pantheon. In the latter part of the following year (1785) Lunardi made several successful ascents from Kelso, Edinburgh and Glasgow (in one of which he traversed a distance of 110 m.); these he described in a second series of letters.

across

Channel.

The first balloon voyage across the English Channel was accomplished by Jean Pierre Blanchard (1753-1809) and Dr. J. Jeffries, an American physician, on the 7th of January Voyages 1785. In the preceding year, on the 2nd of March, Blanchard, who was one of the most celebrated of English the earlier aeronauts, made his first voyage from Paris in a balloon 27 ft. in diameter (fig. 5), and descended at Billancourt near Sèvres. Just as the balloon was about to start, a young man jumped into the car and drawing his sword declared his determination to ascend with Blanchard. He was ultimately removed by force. It has sometimes been incorrectly stated that he Napoleon Bonaparte; his name in reality was Dupont de Chambon. In their Channel crossing Blanchard and his companion, who

But it was Vincent Lunardi who practically introduced aerostation into Great Britain. Although Tytler had the The first ascent from Ireland was made on the 19th of January precedence by a few days still his attempts and partial success 1785 by a Mr Crosbie, who on the following 19th of July atwere all but unknown; whereas Lunardi's experiments excited tempted to cross St George's Channel to England but fell into an enormous amount of enthusiasm in London. He was secrethe sea. The second person who ascended from Ireland was tary to Prince Caramanico, the Neapolitan ambassador, and his Richard Maguire. Mr Crosbie had inflated his balloon on the published letters to his guardian, the chevalier Compagni, 12th of May 1785, but it was unable to take him up. Maguire written while he was carrying in these circumstances offered himself as a substitute, and his out his project, and detail-offer being accepted he made the ascent. For this he was ing all the difficulties, &c., he knighted by the Lord-Lieutenant. Another attempt to cross met with as they occurred, St George's Channel was made by James Sadler on the 1st of give an interesting and vivid October 1812, and he had nearly succeeded when in consequence account of the whole matter. of a change of wind he was forced to descend into the sea off His balloon was 33 ft. in Liverpool, whence he was rescued by a fishing-boat. But on circumference (fig.4), and was the 22nd of July 1817 his second son, Windham Sadler, succeeded exposed to the public view in crossing from Dublin to Holyhead. at the Lyceum in the Strand, where it was visited by upwards of 20,000 people. He originally intended to ascend from Chelsea Hospital, but the conduct of a crowd at a garden at Chelsea, which destroyed the fire-balloon of a Frenchman named de Moret, who announced an ascent on the 11th of August, but was unable to keep his word, led FIG. 4.-Lunardi's Balloon. to the withdrawal of the leave that had been granted. Ultimately he was permitted to ascend from the Artillery ground, and on the 15th of September 1784 the inflation with hydrogen gas took place. It was intended that an English gentleman named Biggin should accompany Lunardi; but the crowd becoming impatient, the latter judged it prudent to ascend with the balloon only partially full rather than risk a longer delay, and accordingly Mr Biggin was obliged to leave the car. Lunardi therefore ascended alone, in presence of the prince of Wales and an enormous crowd of spectators. He took up with him a pigeon, a dog and a cat, and the balloon was provided with oars, by means of which he hoped to raise or lower it at pleasure. Shortly after starting the pigeon escaped, and one of the oars became broken and fell to the ground. In about an hour and a half he descended at South Mimms, in Hertfordshire, and landed the cat, which had suffered from the cold: he then ascended again, and descended, after the lapse of about three-quarters of an hour, at Standon, near Ware, where he had great difficulty in inducing the peasants to come to his assistance; but at length a young woman, taking hold of one of the cords, urged the men to follow her example, which they then did. The excitement caused by this ascent was immense, and Lunardi at once became the star of the hour. He was presented to the king, and was courted and flattered on all sides. To show the enthusiasm displayed by the people during his ascent, he tells himself, in his sixth letter, how a lady, mistaking the oar which fell for himself, was so affected by his supposed destruction that she died in a few days; but, on the other hand, he says he was told by the judges "that he had certainly saved the life of a young man who might possibly be reformed, and be to the public a compensation for the death of the lady"; for the jury were deliberating on the fate of a criminal, whom they must ultimately have condemned, when the balloon appeared, and to save time they gave a verdict of acquittal, and the whole court 1 Mr Tytier contributed largely to, and, indeed, appears to have been virtually editor ot, the second edition (1778-1783) of the Encyclopaedia Britannica.

[graphic]
[graphic]

was

started from Dover, when about one-third across found themselves descending, and threw out every available thing from the boat or car. When about threequarters across they

were

FIG. 5.-Blanchard's Balloon.

descending A, Balloon of taffeta, 26 ft. in diameter, had covered with a net.

to

balloon.

again, and
throw out not only D, D, D, D, Wings worked by rack-work E.
B, Car suspended by cords from hoop C.
the anchor and cords, F, Parachute to break the force of descent
but also to strip and should the balloon burst.
throw away part of G, Tube communicating with inside of
their clothing, after
which they found they were rising, and their last resource, viz.
to cut away the car, was rendered unnecessary. As they ap-
proached the shore the balloon rose, describing a magnificent arch
high over the land. They descended in the forest of Guinnes.

On the 15th of June 1785, Pilâtre de Rozier made an attempt to repeat the exploit of Blanchard and Jeffries in the reverse direction, and cross from Boulogne to England. For this

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