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