THE KITE—THE AEROPHANE—ICE YACHTS—SAILING TRUCKS—WATER VELOCIPEDES.
The kite, known from the earliest times, and constructed by a number of people, is a very familiar object, which we shall not describe; for we will now speak of some similar appliances of a more interesting and uncommon description.
Fig. 475.—Mr. Penaud’s “High-flier.”
M. Penaud has invented some appliances in which twisted india-rubber is the principal agent. Fig. 475 represents a sort of kite, which rises in the air if one twists and then looses the india-rubber round the central bow. Fig. 476 represents another kind of invention; it is an “aerophane,” with a screw at the back, so fixed that it receives no shock from striking against any obstacle. After having twisted the india-rubber, and loosened our hold of the apparatus in a horizontal position, it will first descend for an instant, then, acquiring increased speed, it rises seven or eight feet from the ground, and describes a regular movement in the air for a distance of about fifty yards; the motion lasts for several seconds.
Some models have also been constructed capable of traversing a distance of over seventy yards, remaining for thirteen seconds in the air, as lightly poised as a bird, and without any connection with the ground. During the whole time the rudder restrains with perfect exactitude the ascending and descending movements as they occur; and we can plainly observe the various oscillations like those of sparrows, or more especially woodpeckers. At last, when the movements are coming to an end, the apparatus falls gently to the ground in a slanting line.
Fig 476.—M. Penaud’s “Aerophane.”
M. Penaud has also succeeded in constructing a mechanical bird, that we have seen set in motion, which will continue flying for several seconds; we give an illustration of it in fig. 477.
Another scientist, M. Tatin, has also produced some remarkable results. His efforts have been unceasingly directed towards the reproduction of the flight of a bird by means of more or less complicated arrangements. He has endeavoured to discover in the small appliances made with indiarubber, and used by MM. Penaud and Hureau de Villeneuve, what were the best shapes in which to reproduce the wings, in order to adapt them to a large apparatus acting by compressed air. After several attempts, he decided on the employment of long, narrow wings. Wenham had previously proved that a wing may be equally effectual whether it be narrow or wide, and M. Marcy has also declared that birds with a quick, narrow wing-stroke have always very long wings. By means of these long, narrow wings (fig. 478) M. Tatin has reduced the time during which the wing reaches a suitable position for acting on the air when it first descends. Granted the fact, so long established, that a bird flies more easily if it rests its wing against a great volume of air, it will be understood that the maximum speed of movement will also be the most advantageous as regards the reduction of expended force. The inventor, finding that he could not prevent his mechanical birds from losing force in proportion as they attained considerable speed, remedied this defect by placing the centre of gravity in front. In consequence of this, the bird in full flight preserves the same equilibrium as the bird hovering in the air, and its speed is, to a certain extent, passive, the mass of air pressing of its own accord against the wings, all expenditure of force therefore being utilized for suspension. Thus has M. Tatin been enabled to increase the weight of his appliances, without increasing the motive power, and yet obtains a double course.