This reading material arrived from Washington at a time when Katharine Wright had just returned from Oberlin College, accompanied by a young woman classmate. She had assumed that her brothers would help to entertain this guest, but, to her vexation, Wilbur and Orville had become too absorbed in their reading to have much time for girls. It was now evident to the brothers that though the previous ten years had been a period of unusual activity, the results had not been encouraging. Maxim, after spending one hundred thousand dollars, had abandoned his work; the Ader machine, built at the expense of the French government, had been a failure; Lilienthal in Germany, and Pilcher, a marine engineer, in England, had been killed while trying to glide; Octave Chanute, too, after making some experiments in gliding, had quit. Since Lilienthal had already aroused the brothers’ admiration, they were especially interested in what he had done. With hundreds of short flights, he had had more flying practice than anyone else, even though he had been in the air a total of only five hours in five years. Lilienthal became the Wrights’ hero. They decided that he, by his experiments, had made more advance in the flying art than had anyone else up to that time--an opinion, it may be added, that they never changed. Their reading now gave the Wrights a good idea of how earlier experimenters had attempted to solve the problem of equilibrium. Some experimenters had placed the center of gravity far below the wings, on the theory that the weight would seek to remain at the lowest point. But it had been proved that the wings would then oscillate about the center of gravity in a manner destructive to stability. Others had arranged the wings in the shape of a broad V, to form a dihedral angle, with the center low and the wing tips elevated. This, too, tended to make the machine oscillate from side to side except in calm air. Pénaud, in his models propelled by rubber bands, had used wings that formed a dihedral angle, and a rear stabilizer set with its forward edge lower than the rear edge. This produced inherent stability in both lateral and longitudinal directions. Lilienthal, Chanute, and some of the others had used the Pénaud system in their gliders, but in addition to that system they counted on shifting the weight of their bodies to help maintain equilibrium. All this reading, while adding to their store of knowledge, also gave the Wrights much misinformation. One wrong idea they got was that men already knew how to design wings and propellers of such efficiency that motors then available could easily sustain the machine in the air; another, that the greatest problem was to maintain equilibrium. They also were misled into thinking that fore and aft control of a flying machine would be much more difficult than lateral control.