Contemporary with Pilcher, Mr. Octave Chanute and Mr. A. M. Herring, in America, were emulating the work of Lilienthal. Mr. Chanute was an experienced civil engineer, who had previously written a history of aviation, and experimented with numerous flying models; Mr. Herring, his employee for the time, was a mechanical engineer who had assisted in Langley’s experiments, and previously had flown a Lilienthal glider, and had made researches in the science of mechanical flight. On June 22, 1896, accompanied by two assistants, they went into camp among the sand dunes, on the southern shore of Lake Michigan, to study the art of navigating an aëroplane without artificial motive power. Mr. Chanute thought that the maintenance of equilibrium under all circumstances was at that time the most important problem of aviation; and that until automatic stability was secured, it would be premature and dangerous to apply a motor. He wished to evade, for he did not relish, Lilienthal’s way of balancing by shifting the body and kicking wildly at the stars. His main purpose, therefore, was to acquire the pilot’s science; but secondarily he would learn much about the architecture of gliders, the behavior of air currents, the elements of propulsion and sustentation. PLATE XVII. [Illustration: CHANUTE’S FIVE DECK GLIDER.] [Illustration: HERRING IN CHANUTE BIPLANE.] [Illustration: HERRING’S COMPRESSED-AIR BIPLANE. (Courtesy Carl Dientsbach.)] They made some flights with a Lilienthal monoplane; but, finding this unsafe and treacherous, they discarded it in favor of a multiple-wing glider designed by Chanute, which after many empirical modifications in the placement of the sustaining surfaces, assumed the form shown in Plate XVII. This glider resembled the Lilienthal biplane in having the surfaces vertically superposed, the rider below them, and the rudder in the rear; but it was a five-decker whose wings, on either side, could swerve fore and aft, so as to bring the center of lift always over the center of gravity, in order to prevent excessive rearing or plunging. This glider was found very tractable in a twenty-mile wind, and in a thirteen-mile breeze would sail down a slope of one in four. After further study, the five-decker was replaced by a three-decker; which presently was deprived of its obtrusive and unessential lower surface, thus assuming the familiar form shown in Plate XVII. As will be observed, this was a radically new and elegant design, consisting of two superposed arched surfaces held together by vertical posts and diagonal wires, like a Pratt truss. It was, in fact, the renowned “Chanute glider” which has been copied by so many succeeding designers of biplanes.