时间: 2019年12月15日 18:52

Thus, to the end of the 1901 experiments, Wilbur Wright provided a fairly full account of what was accomplished; the record shows an amount of patient and painstaking work almost beyond belief鈥攊t was no question of making a plane and launching it, but a business of trial and error, investigation and tabulation166 of detail, and the rejection time after time of previously accepted theories, till the brothers must have felt that the solid earth was no longer secure, at times. Though it was Wilbur who set down this and other records of the work done, yet the actual work was so much Orville鈥檚 as his brother鈥檚 that no analysis could separate any set of experiments and say that Orville did this and Wilbur did that鈥攖he two were inseparable. On this point Griffith Brewer remarked that 鈥榠n the arguments, if one brother took one view, the other brother took the opposite view as a matter of course, and the subject was thrashed to pieces until a mutually acceptable result remained. I have often been asked since these pioneer days, 鈥淭ell me, Brewer, who was really the originator of those two?鈥?In reply, I used first to say, 鈥淚 think it was mostly Wilbur,鈥?and later, when I came to know Orville better, I said, 鈥淭he thing could not have been done without Orville.鈥?Now, when asked, I find I have to say, 鈥淚 don鈥檛 know,鈥?and I feel the more I think of it that it was only the wonderful combination of these two brothers, who devoted their lives together for this common object, that made the discovery of the art of flying possible.鈥? Is Mrs. [coughs] at home? Pray present my compliments to her, and say that a gentleman who has lost his way entreats the favour of shelter for a night under her hospitable roof. Zeppelin was far from satisfied with the performance353 of this vessel, and he therefore set about collecting funds for the construction of a second, which was completed in 1905. By this time the internal combustion engine had been greatly improved, and without any increase of weight, Zeppelin was able to instal two motors of 85 horse-power each. The total capacity was 367,000 cubic feet of hydrogen, carried in 16 gas bags inside the framework, and the weight of the whole construction was 9 tons鈥攁 ton less than that of the first Zeppelin airship. Three vertical planes at front and rear controlled horizontal steering, while rise and fall was controlled by horizontal planes arranged in box form. Accident attended the first trial of this second airship, which took place over the Bodensee on November 30th, 1905. 鈥業t had been intended to tow the raft, to which it was anchored, further from the shore against the wind. But the water was too low to allow the use of the raft. The balloon was therefore mounted on pontoons, pulled out into the lake, and taken in tow by a motor-boat. It was caught by a strong wind which was blowing from the shore, and driven ahead at such a rate that it overtook the motor-boat. The tow rope was therefore at once cut, but it unexpectedly formed into knots and became entangled with the airship, pulling the front end down into the water. The balloon was then caught by the wind and lifted into the air, when the propellers were set in motion. The front end was at this instant pointing in a downward direction, and consequently it shot into the water, where it was found necessary to open the valves.鈥?4 Having reached the present stage of advancement in its development, it would seem highly desirable, before laying down the investigation, to obtain conclusive proof of the possibility of free flight, not only because there are excellent reasons to hope for success, but because it marks the end of a definite step toward the attainment of the final goal. 鈥楾he act of flying requires less exertion than from the appearance is supposed. Not having sufficient data to ascertain the exact degree of propelling power exerted by birds in the act of flying, it is uncertain what degree of energy may be required in this respect for vessels of aerial navigation; yet when we consider the many hundreds of miles of continued flight exerted by birds of passage, the idea of its being only a small effort is greatly corroborated. To apply the power of the first mover to the greatest advantage in producing this effect is a very material point. The mode universally adopted by Nature is the oblique waft of the wing. We have only to choose between the direct beat overtaking the velocity of the current, like the oar of a boat, or one applied like the wing, in some assigned degree of obliquity to it. Suppose 35 feet per second to be the velocity of an aerial vehicle, the oar must be moved with this speed previous to its being able to receive any resistance; then if it be only required to obtain a pressure of one-tenth of a lb. upon each square foot it must exceed the velocity of the current 7.3 feet per second. Hence its whole velocity must be 42.5 feet per second. Should the same surface be wafted downward like a wing with the hinder edge inclined upward in an angle of about 50 deg. 40 feet to the current it will overtake it at a velocity of 3.5 feet per second; and as a slight unknown angle of resistance generates a lb. pressure per square foot at this velocity, probably a waft of a little more than 4 feet per second would produce this effect, one-tenth part of which would be the propelling power. The advantage of this mode of48 application compared with the former is rather more than ten to one. 鈥楩eb. 20.鈥擬era Bhatija and I took rather a long walk this afternoon, to look at a lovely little mosque. I had said before to Francis, 鈥淗ow is it that the mosques are so beautiful, and our churches here鈥攗nless expensively built鈥攕o ugly?鈥?Francis gave me a simple but good reason: 鈥淲e want people to go into our churches; the Muhammadans worship outside theirs.鈥?You see, love, we have first to think of room and comfort; so beauty gets shoved into a corner. 日本毛片免费韩国,毛片基地日本,中韩国免费,日本毛片免费韩国福利 The play is, of course, historical, and is of considerable length. One short quotation may be given as a specimen of her girlish powers, taken from Scene II. Old Max looked round triumphantly, and proceeded to follow up the impression thus made. "And then I'm to be told," said he, "that the lunatic doings on Whit Meadow are the work of Heavenly powers, eh? Come, Gladwish鈥攜ou're a man as has read theologies and controversies, and are acquainted with the history of Wesleyan Methodism as well as most members in Whitford鈥擨 should like to know what arguments you have to advance against plain facts鈥攆acts known to us all, and testified to by Robert Blogg, linendraper, now present, and for many years a respected class-leader in this town?" 鈥楾he blessing she (Miss Tucker) is among those Christian boys is incalculable. Perhaps Eternity will show even more fruit from her bright, loving, holy influence over them, than over the people in the city. They are more able to appreciate her character and teaching than the poor degraded heathen, to whom she is much more like an angel afar off and above them, than a sister-woman whom they may seek to follow and grow like. Having stated how the thing is to be done, Walker is careful to explain that when it is done there will be in it some practical use, notably in respect of the conveyance of mails and newspapers, or the saving of life at sea, or for exploration, etc. It might even reduce the number of horses kept by man for his use, by means of which a large amount of land might be set free for the growth of food for human consumption. Later experimenters in this direction were Kress, a German; Professor Wellner, an Austrian; and W. R. Kimball, an American. Kress, like most Germans, set to the development of an idea which others had originated; he followed de la Landelle and Forlanini by fitting two superposed propellers revolving in opposite directions, and with this machine he achieved good results as regards horse-power to weight; Kimball, it appears, did not get beyond the rubber-driven model stage, and any success he may have achieved was modified by the theory enunciated by Berriman and quoted above.