CHAPTER XX. The rate of fall is slow in parachuting to the ground. Frau Poitevin, making a descent from a height of 6,000 feet, took 45 minutes to reach the ground, and, when she alighted, her husband, who had taken her up, had nearly got his balloon packed up. Robertson, another parachutist, is said to have descended from a height379 of 10,000 feet in 35 minutes, or at a rate of nearly 5 feet per second. During the War Brigadier-General Maitland made a parachute descent from a height of 10,000 feet, the time taken being about 20 minutes. Castalia remained leaning with one hand on the table, and did not continue her speech during the second or two in which these thoughts and intentions were passing through old Maxfield's brain. But it was by no means that she hesitated from embarrassment or lack of words: rather the words crowded to her lips too quickly and fiercely for utterance. Through all the languid insolence of her manner there was discernible so much real pain of mind, that Minnie once more checked a severe speech, and answered gently, "You will judge of that. Of course Algernon will discuss the subject of our conversation with you." Borelli鈥檚 study is divided into a series of propositions in which he traces the principles of flight, and the mechanical actions of the wings of birds. The most interesting of these are the propositions in which he sets forth the method in which birds move their wings during flight and the manner in which the air offers resistance to the stroke of the wing. With regard to the first of these two points he says: 鈥榃hen birds in repose rest on the earth their wings are folded up close against their flanks, but when wishing to start on their flight they first bend their legs and leap into the air. Whereupon the joints of their wings are straightened out to form a straight line at right angles to the lateral surface of the breast, so that the two wings, outstretched, are placed, as it were, like the arms of a cross to the body of the bird. Next, since the wings with their feathers attached form almost a plane surface, they are raised slightly above the horizontal, and with a most quick impulse beat down in a direction almost perpendicular to the wing-plane, upon the underlying air; and to so intense a beat the air, notwithstanding it to be fluid,23 offers resistance, partly by reason of its natural inertia, which seeks to retain it at rest, and partly because the particles of the air, compressed by the swiftness of the stroke, resist this compression by their elasticity, just like the hard ground. Hence the whole mass of the bird rebounds, making a fresh leap through the air; whence it follows that flight is simply a motion composed of successive leaps accomplished through the air. And I remark that a wing can easily beat the air in a direction almost perpendicular to its plane surface, although only a single one of the corners of the humerus bone is attached to the scapula, the whole extent of its base remaining free and loose, while the greater transverse feathers are joined to the lateral skin of the thorax. Nevertheless the wing can easily revolve about its base like unto a fan. Nor are there lacking tendon ligaments which restrain the feathers and prevent them from opening farther, in the same fashion that sheets hold in the sails of ships. No less admirable is nature鈥檚 cunning in unfolding and folding the wings upwards, for she folds them not laterally, but by moving upwards edgewise the osseous parts wherein the roots of the feathers are inserted; for thus, without encountering the air鈥檚 resistance the upward motion of the wing surface is made as with a sword, hence they can be uplifted with but small force. But thereafter when the wings are twisted by being drawn transversely and by the resistance of the air, they are flattened as has been declared and will be made manifest hereafter.鈥? 免费a级毛片 Charles. Then you must know that the coming of the Colonel is hangably inconvenient to me. Other instances of successful vertical design鈥攖he types already detailed are fully sufficient to give particulars of the type generally鈥攁re the Panhard, Chenu, Maybach, N.A.G., Argus, Mulag, and the well-known Austro-Daimler, which by 1917 was being copied in every combatant country. There are also the later Wright engines, and in America the Wisconsin six-cylinder vertical, weighing well under 4 lbs. per horse-power, is evidence of the progress made with this first type of aero engine to develop. Maxfield had no retrospective softness on the subject. He, indeed, being accustomed to take certain passages of the Old Testament very seriously and literally, and having fed his mind almost exclusively upon those passages, was of opinion that Castalia's tragic fate had been brought about by a direct interposition of Providence as a judgment on her for her bad behaviour to himself and his daughter. And if this opinion on Maxfield's part should appear incredibly monstrous, let it be remembered that in his own mind "the godly" were typified by the Maxfield family, and "the ungodly" by the enemies of that family. Must I? she answered gloomily. No record of early British fliers could be made without the name of C. S. Rolls, a son of Lord Llangattock. On June 2nd, 1910, he flew across the English Channel to France, until he was duly observed over French territory, when he returned to England without alighting. The trip was made on a Wright biplane, and was the third Channel crossing by air, Bleriot having made the first, and Jacques de Lesseps the second. Rolls was first to make the return journey in one trip. He was eventually killed through the breaking of the tail-plane of his machine in descending at a flying meeting at Bournemouth. The machine was a Wright biplane, but the design of the tail-plane鈥攚hich, by the way, was an addition to the machine, and was not even sanctioned by the Wrights鈥攁ppears to have been carelessly executed, and the plane itself was faulty in construction. The breakage caused the machine to overturn, killing Rolls, who was piloting it.