I do believe you. I believe you are really fond of me. Only鈥攐f course you are much cleverer and wiser than I am, except in thinking too much of me鈥攁nd you can say just whatever is in your mind. But I can't; not all at once. 鈥楬ow are the dear little Robins? I hope that we may soon have them with us again. Pray give them plenty of kisses from Auntie Charlotte.... I hope dear Robin got home comfortably.鈥? Speaking of Frederick at this time, Bielfeld says: 鈥淣otwithstanding all the fatigues of war, the king is in perfect health, and more gay and pleasant than ever. All who approach his majesty meet with a most gracious reception. In the midst of his camp, and at the head of sixty thousand Prussians, our monarch appears to me with a new and superior air of greatness.鈥? On the fifth of June, 1783, the Montgolfiers鈥?hot-air balloon rose at Versailles, and in its rising divided the study of the conquest of the air into two definite parts, the one being concerned with the propulsion of gas lifted, lighter-than-air vehicles, and the other being crystallised in one sentence by Sir George Cayley: 鈥楾he whole problem,鈥?he stated, 鈥榠s confined within these limits, viz.: to make a surface support a given weight by the application of power to the resistance of the air.鈥?For about ten years the balloon held the field entirely, being regarded as the only solution of the problem of flight that man could ever compass. So definite for a time was this view on the eastern side of the Channel that for some years practically all the progress that was made in the development of power-driven planes was made in Britain. 日本电影院-日本?亚洲?国产?中文字幕 Legend and doubtful history carries up to the fifteenth century, and then came Leonardo da Vinci, first student of flight whose work endures to the present day. The world knows da Vinci as artist; his age knew him as architect, engineer, artist, and scientist16 in an age when science was a single study, comprising all knowledge from mathematics to medicine. He was, of course, in league with the devil, for in no other way could his range of knowledge and observation be explained by his contemporaries; he left a Treatise on the Flight of Birds in which are statements and deductions that had to be rediscovered when the Treatise had been forgotten鈥攄a Vinci anticipated modern knowledge as Plato anticipated modern thought, and blazed the first broad trail toward flight. The process is simple. They keep sending 'em in! Theoretically the two-stroke and the four-stroke cycle engines possess exactly the same thermal efficiency, but actually this is modified by a series of practical conditions which to some extent tend to neutralise the very strong case in favour of the two-stroke cycle engine. The specific capacity of the engine operating on the two-stroke principle is theoretically twice that of one operating on the four-stroke cycle, and consequently, for equal power, the former should require only about half the cylinder volume of the latter; and, owing to the greater superficial area of the smaller cylinder, relatively, the latter should be far more easily cooled than the larger four-stroke cycle cylinder; thus it should be possible to get higher compression pressures, which in turn should result in great economy of working. Also the obtaining of a working impulse in the cylinder for each revolution of the crankshaft should give a great advantage in regularity of rotation鈥攚hich it undoubtedly does鈥攁nd the elimination of the operating gear for the valves, inlet and exhaust, should give greater simplicity of design. Oh, she merely cried and whimpered, and hid her face in her apron. She is terribly weak-minded, poor creature. The giant twin-engined Handley-Page bomber was tried out, proved efficient, and justly considered better than anything of its kind that had previously taken the field. Immediately after the conclusion of its trials, a specimen of the type was delivered intact at Lille for the Germans to copy, the innocent pilot responsible for the delivery doing some great disservice to his own cause. The Gotha Wagon-Fabrik Firm immediately set to work and copied the Handley-Page design, producing the great Gotha bombing machine which was used in all the later raids on England as well as for night work over the Allied lines.