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CONDUCTED BY WILLIAM AND ROBERT CHAMBERS, EDITORS OF 'CHAMBERS'S INFORMATION FOR THE PEOPLE,' 'CHAMBERS'S EDUCATIONAL COURSE,' &c.
| No. 431. New Series. | SATURDAY, APRIL 3, 1852. | Price 1½d. |
AIR-TRAVELLING.
It may be generally known, that for some time extraordinary efforts have been making to discover a method by which locomotion through the air may be rendered as certain and practicable as locomotion by sea or land. In this desperate enterprise, of bringing the principle of aërostation into regular use, certain individuals in Paris have taken the lead. Our belief, like that of others, is, that plans of this kind will fail, as they have hitherto done; at the same time, we think it would be improper to dogmatise on the subject, and will only say, that if travelling by balloon becomes one of the established things of the day, so much the better.
With these feelings, we have thought it consistent with our duty as journalists, not to refuse publicity to an account of what was till lately doing in Paris to forward practical aërostation—we say, lately; for we are told by our correspondent, that the operations towards perfecting the invention have been stopped by orders of the French government, from an opinion that, if air-travelling were introduced, it would be injurious to the custom-house, and denationalise the country. This resolution of the French government is to be regretted, not less on the score of science, than from the ruin it has inflicted on the modest means of the ingenious operator. With these preliminary explanations, we offer the following paper, just as handed to us by a respectable party conversant with the details to which he refers.
'The chief difficulty in aëro-locomotion, is that of steering; because the atmosphere seems to present no substantial fulcrum which can be pushed against. But that this difficulty is not altogether insurmountable, is evident from the single fact, that birds really do steer their way through the air. This fact suggests, that a fulcrum is not necessarily a palpable substance: it may be pliant or movable. For instance, if we fasten the string of a kite to a ball, this ball, which represents the fulcrum, being set in motion by the kite, becomes a movable fulcrum: a child also, holding the string in his hand, runs from right to left without impeding the motion of the kite, of which motion he is the movable fulcrum. Absolute stability, therefore, is not a necessary condition of a fulcrum; it is sufficient that there be, between the resistant force and the motive force, a difference of intensity in favour of the former. Thus, in water, the fulcrum, being liquid, is necessarily pliant and movable; yet it is quite possible, as every child knows, to obtain in this element purchase sufficient to steer the largest ships.
'In the air, which is a gas, the fulcrum being gaseous, must also be movable; but although the air, being the most elastic body with which we are acquainted, is therefore the least apt to furnish a fulcrum, yet, as compressed air is capable of bursting the strongest metallic receptacles, splitting the solid rock, and rending the bosom of the earth, it would seem that we have only to act upon the air through pressure, in order to obtain the requisite purchase from which to steer.
'Foremost among those who are thus endeavouring to render the balloon manageable, is M. Pétin of Paris, who has devoted fifteen years to the study of this subject, the last three years to lecturing upon it in the principal towns of France, and who has unfortunately expended the whole of his resources in constructing an air-ship intended to demonstrate, on a small scale, the possibility of steering according to the system which he has elucidated. We say on a small scale; for though the dimensions of the curious construction in question, intended to carry two hundred passengers, will appear large to those of our readers whose ideas of ballooning have never gone beyond the ordinary ascensions so much in vogue at the present day, they are yet of almost microscopic minuteness when compared with the developments of which M. Pétin and his friends conceive his plans to be susceptible!
'The body of this novel vessel consists of two covered decks, or galleries, connected by a series of narrow bridges, thrown across the open space between them, on a level with their floor; thus forming the body of the vessel, which looks not unlike a couple of Noah's Arks, placed parallel to each other, and connected by means of the aforesaid bridges. Suspended across the upper part of this open space, is a row of sixteen movable wings, placed one behind the other, and attached, by means of pivots, to the upper edge of the inner walls of the galleries; these wings are of oiled sail-cloth, set into oblong iron frames, and are worked by machinery. They may be opened or closed, inclined to or from each other, at any angle, upwards or downwards. At each end of the vessel, near the stem and the stern, is a pair of screws, similar to the propellers of a steam-ship, and worked by a couple of small steam-engines of three horse-power each, one being placed just above and behind each pair of screws. Lastly, attached to masts projecting horizontally from each end of the ship, are a couple of triangular or lateen sails; smaller sails are also attached to the under part of the balloons, which, enclosed in net-work of strong cord, are fastened to the roof of the galleries, directly over the wings, beneath which, again, are the bridges from which the crew are to work the ship.
'These skeleton galleries, which, with the exception of the floors, and the walls and roof of their central portion, are constructed of lattice-work, faced with thin bands of iron, in order to render the whole as light as possible, are 162 feet in length, 8 feet in height by 4 feet in width in their central portion, but taper off to 18 inches in height and width at their extremities. This mode of building gives an oval form to the framework of the vessel. The central portion of the galleries, which is at the same time the highest and the widest, embraces a length of 66 feet, and is appropriated to the passengers. The boilers are placed here also, one in each gallery; the steam being conveyed to the engines by pipes.
'The total length of the ship, including that of the two projecting masts, is 198 feet; and its total weight, including that of the machinery, and a crew of eight men, is 14,000 pounds. The balloons are 66 feet in diameter, and will contain 15,000 cubic yards of gas. Their ascensional force is 20,000 pounds. The wings are 6 feet in length by 15 in width. The screws are made of pitched canvas, rimmed with iron; they are 6 feet in length.
'The eight central wings, disposed in the form of an upright roof—parachute—or of an inverted roof—paramont—are intended, by pressing on the air above in ascending, and on the air below in descending, to furnish the necessary point of resistance, or fulcrum, from which to steer. The other eight wings, four at each end of the central group, are intended, by being opened or shut, to act as a counterpoise; thus producing a rupture of equilibrium around the central fulcrum, and thereby changing the upward movement of the balloons into an oblique forward movement. In other words, the ship being raised into the air—to the stratum immediately above the region of storms—and maintained there by the ascensional force of the balloons, and being forced onward by the screws, the four anterior wings are to be opened, the four posterior ones remaining closed. The forepart of the ship being now relieved from the downward pressure of the air, caused by the upward movement of the balloons, this pressure still acting on the posterior wings, its equilibrium is destroyed; the forepart rises, the hindpart dips, thus changing the direction of the ship's course, by converting its vertical into an oblique movement, which is to carry it onward upon a plane inclined slightly upward.
'This operation is to be followed by its converse. The four posterior wings are to be opened, and the four anterior ones closed; the vessel now dips in the opposite direction, and moves forward on a plane inclined slightly downward; and so on. Thus, by alternately opening and shutting the two sets of lateral wings, M. Pétin proposes to make his ship sail forward on a series of inclined planes, upwards and downwards. He takes care to assure us, however, that the requisite degree of inclination will be so slight as to be imperceptible to his passengers; and instances, in corroboration of this opinion, the beds of rivers, where a very slight degree of inclination suffices to produce a rapid current.
'In order to determine perpendicular movement, the central wings—which, according to M. Pétin, when placed in an oblique position, will constitute the fulcrum—are to be brought into an upright position, thus offering no resistance to the air; the two pairs of screws are then made to turn in opposite directions with great velocity, forcing powerful convergent currents of air upon the two sets of lateral wings, maintained in oblique and opposite positions. The force of these currents, being decomposed by the resistance of the wings, is thus changed into a perpendicular pressure, acting upwards or downwards according to the position of the wings; by means of which the aëronaut hopes to be enabled to ascend or descend without losing either gas or ballast.
'This decomposition of the force of the currents produced by the screws, is analogous to that effected by the sails of a ship sailing across the wind; where, the sails being inclined at an angle of 45 degrees to the course of the wind, the ship is impelled onwards in a direction at right angles to that of the wind: the only difference in the two cases being this—namely, that in the sails of the ship, the axis of inclination, represented by the mast, is vertical, creating horizontal movement; while, in the wings of the air-ship, the axis of inclination—the pivot on which they turn—is horizontal, creating vertical movement. Were there but one pair of screws, acting upon one set of inclined wings, a slight retrograde horizontal movement would be produced in addition to the vertical movement, as the current of blast from the screw would react upon the screw itself with a force greater than that with which it would impinge upon the wings, where a part of the blast will inevitably be wasted. But there being two pairs of screws, acting in opposite directions, they will neutralise each other's horizontal movement, while combining in the production of vertical movement. So, at least, reasons our inventor; but however ingenious this expedient, its efficiency may well be doubted, when we remember the immense amount of resistance, offered by the surface of the balloons, which would have to be overcome.
'To obtain lateral movement, the action of one pair of screws is suspended, leaving the other pair in motion: the ship, according to the calculation of M. Pétin, will immediately describe a curve, and turn.
'Such is the air-ship constructed by M. Pétin; but, unhappily for the demonstration of his views, the French government, either from fear of accident, or from some other motive, has interdicted its ascension; and the vessel which, three months ago, was ready—crew, captain, and machinery—to attempt its advertised flight round the walls of Paris, is still reposing, in inglorious idleness, upon its stocks in the Chantier Marbeuf (Champs Elysées), to the woful disappointment of its enthusiastic inventor, who, however, consoles himself with the hope of coming over to London for the purpose of testing his invention, as soon as the return of fine weather shall render it prudent to make the trial journey. In justice to M. Pétin, we would observe, that the sole point which he hopes to prove with this vessel is, the possibility of obtaining a fulcrum in the air, justly considering that if the question of steering were affirmatively settled, the necessary means, pecuniary and other, would soon be forthcoming to enable him to improve upon, or to change the original construction, and to build the mammoth vessels, containing closed apartments, warmed and fitted up with every provision for comfort, in which he hopes to transport several thousands of passengers at a time, and at a speed which it almost takes away one's breath to think of.
'For, urges M. Pétin, if we could once succeed in getting a fulcrum in the air in spite of its elasticity, this very elasticity would then enable us, with suitable motive-power, to move with a degree of rapidity far transcending the possibilities of locomotion in any other element. In fact, it would seem, according to M. Pétin's computations, that we might breakfast in London, lunch in Constantinople, dine in China, dance the evening out in Havannah, and get home to bed at an hour not much later than that at which the votaries of fashion usually betake themselves to their slumbers.
'The reasoning by which our inventor arrives at the seemingly paradoxical conclusion, that the air is destined to be the high-road par excellence, and to serve as the medium of transportation for the heaviest loads, is certainly very ingenious; of its conclusiveness, we must leave our readers to judge for themselves.
'Progression from the simple to the composite, says M. Pétin, is the universal law. In the works of nature, the action of this law is everywhere visible; and man, in his works, follows the path thus consecrated by the footsteps of the Creator. Thus we find, he continues, that the point multiplied by itself produces the line; the line, in like manner, produces the plane; and the plane, the cube; an ascending series, which he conceives to have its exact analogy in that furnished by the earth, the water, and the air, considered as media of locomotion. In other words, the point, or primary germ of extension, corresponds, according to the theory of M. Pétin, with the fulcrum, or primary condition of locomotion; the line, first and simplest form of extension, corresponds with locomotion on the surface of the earth, where, owing to topographic inequalities, and other obstacles, locomotion can take place only in its first and simplest mode—namely, in a linear direction; the plane, produced by the movement of the line, and constituting a higher term of superficial development, corresponds with locomotion upon the water, whose unencumbered surface, which can be traversed in every direction, presents a locomotive medium, the facilities of which, compared with those offered by the surface of the earth, increase in the ratio of the difference of extension between the line and the plane.
'The cube, product of the plane multiplied by itself, corresponds with locomotion in the air, where the aëronaut, being surrounded on every side by fulcra furnished by the various strata of the atmosphere, moves at will in every direction; pressing on the higher strata in ascending, on the lower in descending, on the lateral in turning to the right or to the left, and thus commanding a sphere of locomotion whose extent and facilities, compared with those afforded by the water, are as the cube to the plane.
'Aërial navigation being thus, according to his theory, the highest form of locomotion, M. Pétin considers himself as justified in assuming, a priori, that this mode of transportation will offer facilities superior to those of every other in point of safety, speed, power, and cheapness; but on condition of its being carried into effect upon a scale commensurate with the vastness of its field and the importance of its results.
'To convince ourselves that such is really the intention of Providence, and that balloons are destined to transport the heaviest loads, we have only, continues M. Pétin, to examine the law which presides over the development of spheric bodies; the surface of a sphere being represented by the square of the radius, while its contenance, or containing power, is represented by the cube of the radius. In other words, if we increase the diameter of a sphere three times, although we increase its surface only nine times, we increase its containing power twenty-seven times. Therefore, by constructing balloons on a very large scale, as the extent of surface, and consequent resistance of the air, increases in an immensely smaller proportion than the containing power, we may obtain an almost fabulous amount of ascensional force. For instance: a balloon of one hundred yards in diameter would suffice to raise only ten millions of pounds; but ten such balloons ranged one behind the other, or, better still, a cigar-shaped balloon, which would be equivalent to these ten balloons united in one (an arrangement which, as the law of development is similar for spheric and for cylindric bodies, would greatly diminish the resistance of the air, without occasioning any loss of containing power), would suffice to raise one hundred millions of pounds; and allowing some four or five millions of pounds for the weight of the vessel and its machinery, which, for a ship of this size—supposing it were possible to make its various parts hold together—should be, M. Pétin computes, of twelve hundred horse-power, we should still have at command a surplus ascensional force of upwards of ninety millions of pounds; a force sufficient to sustain a body of fifty thousand men!
'In the construction of these enormous balloons, M. Pétin proposes to substitute, in place of the silken bag hitherto used to contain the gas, a rigid envelope of a cylindro-conical form, composed of a series of metallic tubes, laid one above the other, and supplied with gas—obtainable to any amount and almost instantaneously—from the decomposition of water by a powerful electric battery; and with these resources at command, M. Pétin conceives that balloons might be constructed on a scale even larger than that just given!
'In fact, this assumption of the possibility of obtaining command of an unlimited ascensional force has suggested, to certain enthusiastic partisans of M. Pétin's theory and plans, a long perspective of astounding visions, from which sober-minded Englishmen would, in all probability, turn away with derision. These enthusiasts have evidently adopted the language of Archimedes, and are ready to exclaim: "Give us a fulcrum, and," with hydrogen gas as our lever, "we will move the world!"
'For ourselves, we have already stated the facts from which we derive our conviction that the conquest of the air, if achieved, is to be brought about through the agency of new and powerful mechanical combinations, rather than by means of the balloon; and though, as before remarked, the experiments of M. Pétin and others may probably not be without useful results, we dismiss these brilliant phantasmagoria with the charitable reflection, that the extravagance of overweening hopefulness is, at least in an age which has witnessed the advent of steam and electricity, more natural and more pardonable than the scepticism of confirmed despondency; and that "he who shoots at the stars," though missing his aim, will at all events shoot higher than he who aims at the mud beneath his feet.
'Meantime, the science of meteorology—a subject intimately connected with that of aëro-locomotion—though yet in its infancy, already furnishes many indications of great importance, as establishing a very strong presumption in favour of the existence of permanent atmospheric currents, blowing continuously in various directions at different degrees of elevation.
'We know that air, when rarefied by heat, becomes lighter and rises, cold air immediately rushing in to supply its place; and it is evident, therefore, that if two neighbouring regions of the atmosphere are unequally heated, this inequality of temperature will give rise to two currents of air—a warm one, in the upper region of the atmosphere, blowing from the warmer to the colder region; and a cold one, near the surface of the earth, blowing from the colder to the warmer region. It can, therefore, hardly be matter of doubt, that great permanent currents, caused by the unequal heating of the equatorial and polar regions, do exist in the higher strata of the atmosphere—an inference which is supported not only by the occurrence of the trade-winds and the monsoon, but by a variety of other facts and observations.
'Thus, for instance, it is found that in the region of the trade-winds, cinders from the craters of volcanoes, and other objects, are carried through the higher regions of the air in a direction exactly opposite to that in which the trade-wind itself is blowing below; and in this way cinders from the Cosiguina, in Guatemala, frequently fall in the streets of Kingston (Jamaica), lying to the north-east of Guatemala. Similar facts have been observed at the Peak of Teneriffe, in the Straits of Magellan, and elsewhere.
'The importance of this subject with regard to aëro-locomotion can hardly be overrated; for these currents, when clearly ascertained and correctly mapped out, would constitute so many great natural routes, where the aëronaut would be borne onward in the required direction with immense velocity, and without danger of encountering squalls or counter-currents.
'But here, fearful of exhausting the patience of our readers, we bring our somewhat lengthened disquisitions to a close, and take our leave for the present of the tempting, though debatable ground of the Cubic Highway.'