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高清露脸 国内在线网友露脸自拍 国产自拍露脸视频

时间: 2019年12月12日 09:13

� Horatia. [Starting up.] A thought has struck me. She slunk along in the shadow of the houses, frightened at the faint sound of her own footfall on the flagstones, starting nervously at every noise, hurrying across the lighted spaces in front of the few shops that remained open with averted face and beating heart, fearing to be noticed by those within. But never once did she falter in her purpose of following her husband. She would have been turned back by no obstacle short of one which defied her physical powers to pass it. Under an enormous banyan tree, far from any dwelling, two fine statues of an elephant and a horse seemed to guard an image of Siva, rigidly seated, and on his knees an image of Parvati, quite small, and standing as though about to dance. Who's all right? Tomorrow is the first Wednesday in the month--a weary day for the 高清露脸 国内在线网友露脸自拍 国产自拍露脸视频 鈥業n gliding experiments, however, the amount of lift is of less relative importance than the ratio of lift to drift, as this alone decides the angle of gliding descent. In a plane the pressure is always perpendicular to the surface, and the ratio of lift to drift is therefore the same as that of the cosine to the sine of the angle of incidence. But in curved surfaces a very remarkable situation is found. The pressure, instead of being uniformly normal to the chord of the arc, is usually159 inclined considerably in front of the perpendicular. The result is that the lift is greater and the drift less than if the pressure were normal. Lilienthal was the first to discover this exceedingly important fact, which is fully set forth in his book, Bird Flight the Basis of the Flying Art, but owing to some errors in the methods he used in making measurements, question was raised by other investigators not only as to the accuracy of his figures, but even as to the existence of any tangential force at all. Our experiments confirm the existence of this force, though our measurements differ considerably from those of Lilienthal. While at Kitty Hawk we spent much time in measuring the horizontal pressure on our unloaded machine at various angles of incidence. We found that at 13 degrees the horizontal pressure was about 23 lbs. This included not only the drift proper, or horizontal component of the pressure on the side of the surface, but also the head resistance of the framing as well. The weight of the machine at the time of this test was about 108 lbs. Now, if the pressure had been normal to the chord of the surface, the drift proper would have been to the lift (108 lbs.) as the sine of 13 degrees is to the cosine of 13 degrees, or (.22 脳 108) / .97 = 24 + lbs.; but this slightly exceeds the total pull of 23 pounds on our scales. Therefore it is evident that the average pressure on the surface, instead of being normal to the chord, was so far inclined toward the front that all the head resistance of framing and wires used in the construction was more than overcome. In a wind of fourteen miles per hour resistance is by no means a negligible factor, so that tangential is evidently a force of considerable value. In a higher wind, which sustained the machine at an angle of160 10 degrees the pull on the scales was 18 lbs. With the pressure normal to the chord the drift proper would have been (17 脳 98) / 鈥?8. The travel of the centre of pressure made it necessary to put sand on the front rudder to bring the centres of gravity and pressure into coincidence, consequently the weight of the machine varied from 98 lbs. to 108 lbs. in the different tests) = 17 lbs., so that, although the higher wind velocity must have caused an increase in the head resistance, the tangential force still came within 1 lb. of overcoming it. After our return from Kitty Hawk we began a series of experiments to accurately determine the amount and direction of the pressure produced on curved surfaces when acted upon by winds at the various angles from zero to 90 degrees. These experiments are not yet concluded, but in general they support Lilienthal in the claim that the curves give pressures more favourable in amount and direction than planes; but we find marked differences in the exact values, especially at angles below 10 degrees. We were unable to obtain direct measurements of the horizontal pressures of the machine with the operator on board, but by comparing the distance travelled with the vertical fall, it was easily calculated that at a speed of 24 miles per hour the total horizontal resistances of our machine, when bearing the operator, amounted to 40 lbs, which is equivalent to about 2? horse-power. It must not be supposed, however, that a motor developing this power would be sufficient to drive a man-bearing machine. The extra weight of the motor would require either a larger machine, higher speed, or a greater angle of incidence in order to support it, and therefore more power. It is probable, however, that an engine of 6 horse-power,161 weighing 100 lbs. would answer the purpose. Such an engine is entirely practicable. Indeed, working motors of one-half this weight per horse-power (9 lbs. per horse-power) have been constructed by several different builders. Increasing the speed of our machine from 24 to 33 miles per hour reduced the total horizontal pressure from 40 to about 35 lbs. This was quite an advantage in gliding, as it made it possible to sail about 15 per cent farther with a given drop. However, it would be of little or no advantage in reducing the size of the motor in a power-driven machine, because the lessened thrust would be counterbalanced by the increased speed per minute. Some years ago Professor Langley called attention to the great economy of thrust which might be obtained by using very high speeds, and from this many were led to suppose that high speed was essential to success in a motor-driven machine. But the economy to which Professor Langley called attention was in foot pounds per mile of travel, not in foot pounds per minute. It is the foot pounds per minute that fixes the size of the motor. The probability is that the first flying machines will have a relatively low speed, perhaps not much exceeding 20 miles per hour, but the problem of increasing the speed will be much simpler in some respects than that of increasing the speed of a steamboat; for, whereas in the latter case the size of the engine must increase as the cube of the speed, in the flying machine, until extremely high speeds are reached, the capacity of the motor increases in less than simple ratio; and there is even a decrease in the fuel per mile of travel. In other words, to double the speed of a steamship (and the same is true of the balloon type of airship) eight times the engine and boiler capacity162 would be required, and four times the fuel consumption per mile of travel; while a flying machine would require engines of less than double the size, and there would be an actual decrease in the fuel consumption per mile of travel. But looking at the matter conversely, the great disadvantage of the flying machine is apparent; for in the latter no flight at all is possible unless the proportion of horse-power to flying capacity is very high; but on the other hand a steamship is a mechanical success if its ratio of horse-power to tonnage is insignificant. A flying machine that would fly at a speed of 50 miles per hour with engines of 1,000 horse-power would not be upheld by its wings at all at a speed of less than 25 miles an hour, and nothing less than 500 horse-power could drive it at this speed. But a boat which could make 40 miles an hour with engines of 1,000 horse-power would still move 4 miles an hour even if the engines were reduced to 1 horse-power. The problems of land and water travel were solved in the nineteenth century, because it was possible to begin with small achievements, and gradually work up to our present success. The flying problem was left over to the twentieth century, because in this case the art must be highly developed before any flight of any considerable duration at all can be obtained. Interfere with a fiddlestick! cried Algernon in the quick, testy tone that was the nearest approach to loss of temper Minnie had ever seen in him. Then he added after an instant, with a short laugh, "I don't know why I'm supposed not to include dinner in my 'arrangements' to-day of all days in the year!" Of course there are houses of refuge, from which it has been thought expedient to banish everything pleasant, as though the only repentance to which we can afford to give a place must necessarily be one of sackcloth and ashes. It is hardly thus that we can hope to recall those to decency who, if they are to be recalled at all, must be induced to obey the summons before they have reached the last stage of that misery which I have attempted to describe. To me the mistake which we too often make seems to be this 鈥?that the girl who has gone astray is put out of sight, out of mind if possible, at any rate out of speech, as though she had never existed, and that this ferocity comes not only from hatred of the sin, put in part also from a dread of the taint which the sin brings with it. Very low as is the degradation to which a girl is brought when she falls through love or vanity, or perhaps from a longing for luxurious ease, still much lower is that to which she must descend perforce when, through the hardness of the world around her, she converts that sin into a trade. Mothers and sisters, when the misfortune comes upon them of a fallen female from among their number, should remember this, and not fear contamination so strongly as did Carry Brattle鈥檚 married sister and sister-in-law. As to Mrs. Errington, she was so perplexed by her daughter-in-law's sudden change of mood and manner, that she lost her presence of mind, and remained gazing from Algernon to his wife very blankly. "I never knew such a thing!" thought the good lady. "One moment she's raging and scolding, and abusing her husband for deceiving her, and the next she is petting him up as if he was a baby!" Dear Mr. Trustee,