'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!