Langley's Airplane.

Otto Lilienthal and his brother Gustav—the two like the Wrights were always associated in their aviation work—had been studying long the problem of flight when in 1889 they jointly published their book Bird Flight as the Basis of the Flying Art. Their investigations were wholly into the problem of flight without a motor. At the outset they even harked back to the long-abandoned theory that man could raise himself by mere muscular effort, and Otto spent many hours suspended at the end of a rope flapping frantically a pair of wings before he abandoned this effort as futile. Convinced that the soaring or gliding of the birds was the feat to emulate, he made himself a pair of fixed, bat-like wings formed of a light fabric stretched over a willow frame. A tail composed of one vertical and one horizontal plane extended to the rear, and in the middle the aviator hung by his armpits, in an erect position. With this device he made some experimental glides, leaping from slight eminences. With his body, which swung at will from its cushioned supports, he could balance, and even steer the fabric which supported him, and accomplished long glides against the wind. Not infrequently, running into the teeth of the breeze down a gentle slope he would find himself gently wafted into the air and would make flights of as much as three hundred yards, steering to either side, or rising and falling at will. He was even able to make a circuitous flight and return to his starting place—a feat that was not accomplished with a motor-driven airplane until years later. Lilienthal achieved it with no mechanical aid, except the wings. He became passionately devoted to the art, made more than two thousand flights, and at the time of his death had just completed a motor-driven airplane, which he was never able to test. His earlier gliding wings he developed into a form of biplane, with which he made several successful flights, but met his death in 1896 by the collapse of this machine, of the bad condition of which he had been warned.

© Kadel & Herbert.

French Airdrome near the Front.

Lilienthal was more of a factor in the conquest of the air than his actual accomplishments would imply. His persistent experiments, his voluminous writings, and above all his friendly and intelligent interest in the work of other and younger men won him a host of disciples in other lands who took up the work that dropped from his lifeless hands.