Chanute might well have felt pride in the effectiveness of his insistence that the Wrights should go on experimenting, as well as in the results of his invitation to Wilbur to make that Chicago speech. Except for that speech and its daring statements that Orville thought needed more confirmation, there probably would have been no wind-tunnel tests; and without the kind of knowledge then obtained, neither the Wrights nor anyone else could have built a practical flying-machine. Those wind-tunnel experiments marked one of the great turning points in the long history of attempts at human flight. It still remained for the Wrights to put their new knowledge to actual test in gliding, and they set out on August 25, 1902, for their third stay at Kitty Hawk. But not until September 8 were they able to begin the work of assembling their new glider, for the camp, battered by winter gales, needed much repairing; and they decided to build an addition to it for living quarters. They did not have their machine ready for its first trial until September 19. This new glider was of not much greater lifting area than that of the previous year, though the wing span had been increased from twenty-two to thirty-two feet. But since the wind-tunnel experiments had demonstrated the importance of the “aspect ratio,” the total span was now about six times the chord instead of three. One minor change also may be noted. In the earlier gliders, the wing-warping mechanism had been worked by movement of the operator’s feet; but now in this 1902 glider it was done by sidewise movement of one’s hips resting on a “cradle.” The most noticeable change was the addition of a tail, consisting of fixed twin vertical vanes, with a total area of a trifle less than twelve square feet. Its purpose was to correct certain difficulties encountered in some of the flights with the 1901 machine. When the wing surfaces at the right and left sides were warped to present different angles toward the wind, the wing that had the greater angle, and therefore the more resistance, tended to lag behind, and then the slower speed offset what otherwise would have been the greater lifting power of that wing. The tail was expected to counter-balance that difference in resistance of the wing tips. If the wing on one side tended to swerve forward, on a vertical axis, then the tail, more exposed to the wind on that same side, should, it was thought, stop the machine from further turning.