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时间: 2019年12月16日 18:46

The best account of Langley鈥檚 work is that diffused throughout a weighty tome issued by the Smithsonian Institution, entitled the Langley Memoir on Mechanical Flight, of which about one-third was written by Langley himself, the remainder being compiled by Charles M. Manly, the engineer responsible for the construction of the first radial aero engine, and chief assistant to134 Langley in his experiments. To give a twentieth of the contents of this volume in the present short account of the development of mechanical flight would far exceed the amount of space that can be devoted even to so eminent a man in aeronautics as S. P. Langley, who, apart from his achievement in the construction of a power-driven aeroplane really capable of flight, was a scientist of no mean order, and who brought to the study of aeronautics the skill of the trained investigator allied to the inventive resource of the genius. Polly stared at the paper with eager curiosity, but the sharp, slanting writing puzzled her eyes, never quite at their ease with the alphabet in any shape. "Is it missus's writing?" she asked. The following undated letters belong to the years 1846-7. A little sentence in the first, as to the solution of Mr. Tucker鈥檚 enigma, is very characteristic of one who through life was always peculiarly ready to give praise to others. James, 19 years of age, an excellent painter. Old Max was sitting near the dull fire which burned in the grate. The big Bible, his constant companion now, lay open on the table. But he had not been devoting his attention to that solely. He had had a large old-fashioned wooden desk brought down from his own room, and had been fingering the papers in it, reading some, and merely glancing at the outside folds of others. He now looked up at Castalia without recognising her. In 1800 a certain Dr Thomas Young demonstrated that certain curved surfaces suspended by a thread moved into and not away from a horizontal current of air, but the demonstration, which approaches perilously near to perpetual motion if the current be truly horizontal, has never been successfully repeated, so that there is more than a suspicion that Young鈥檚 air-current was not horizontal. Others had made and were making experiments on the resistance offered to the air by flat surfaces,44 when Cayley came to study and record, earning such a place among the pioneers as to win the title of 鈥榝ather of British aeronautics.鈥? 日本毛片高清免费视频_日本无码不卡高清免费 � � This bald statement of the day鈥檚 doings is as Wilbur Wright himself has given it, and there is in truth nothing more to say; no amount of statement could add to the importance of the achievement, and no more than the bare record is necessary. The faith that had inspired the long roll of pioneers, from da Vinci onward, was justified at last. � �