[Illustration: PILCHER’S MONOPLANE GLIDER.] The craft was thought also to possess stability; and this it had, in a measure, about those two axes corresponding to the two rudders; but the control about the third axis, effected by dangling the legs to right or left, was extremely crude and primitive. It was in keeping with his adage: “to contrive is nothing; to construct is something; to operate is everything.” If he had contrived more intelligently, he would have operated more easily, and avoided those wild and dangerous dancings in space. A more scientific adage would read: “To design effectually is everything, to construct is routine, to operate is play.” The marvel is that Lilienthal, the observant, the technically trained, the practically skilled, should operate for three years, then patent, an aërial glider having two rudders, but lacking the third rudder, or torsional wing, now so commonly used throughout the world. But doubtless he contemplated a device for preserving the lateral balance without shifting his weight; for he acknowledged the economic advantage of lying prone on the machine, and stated that this might be done after some important improvements in the apparatus had been made. Having executed nearly two thousand flights with his monoplane, Lilienthal in 1895 built a two-surface glider. He found this still easier to control, and now thought he had sufficiently acquired the art of sailing to justify his undertaking the next and more difficult art of imitating the rowing flight of birds. He had constructed a ninety-pound engine, of two and a half horse power, to actuate the wings of his glider; but, before applying this motor, he went to the Rhinow Hills for a little further experience in sailing. Previously he had remained in the air twelve to fifteen seconds; but he wished to exceed this record. On the 9th of August, 1896, he made a long glide to prove the effectiveness of the horizontal rudder, and then wished to undertake a second flight of the greatest duration feasible. No intimation had he that this sail would prove disastrous. Giving the timepiece to his assistant, he set forth on a level course, but suddenly dipped forward and plunged headlong to earth through a height of fifty feet. He was dragged out from the débris with a broken spine, from which he died the following day.