In 1866, two decades after the flight of Stringfellow’s monoplane, Mr. F. H. Wenham, another Englishman illustrious in the annals of aëronautics, patented the multiplane; that is, an aëroplane comprising two or more superposed surfaces. This proved to be a valuable contribution to the art of aviation, and continues in use at the present time. The device furnished an increase of sustaining surface without enlargement of the ground plan. It moreover lends itself conveniently to a strong and simple trussing of the surfaces. Some designers protest that superposed surfaces blanket one another; but the advantages just named seem amply to compensate for this objectionable feature. If the surfaces be properly spaced, very little interference is found; moreover, any blanketing that may occur diminishes the drift as well as the lift,[20] though not necessarily in the same proportion. Wenham’s aëroplane is illustrated in Fig. 31. The rider lies underneath the multiple wings, so as to diminish the resistance to progression through the air. The apparatus could thus be used as an aërial toboggan for coasting down the atmosphere. To prolong the flights two flappers actuated by a treadle were to be employed, their ends being hinged at a point above the operator’s back. Though the device was patented, no very serious efforts were made to operate it practically. Once, indeed, the inventor took his glider to a meadow and mounted it, during a lull in the evening wind, but soon a gust caught him up, carried him some distance from the ground and toppled him over sidewise, breaking some of the surfaces. The machine disclosed some good working principles; but it was inadequately ruddered, and too feebly constructed, to weather the buffets of the prevailing ground currents. PLATE XIII. [Illustration: STRINGFELLOW’S AËROPLANE (FRONT). (Courtesy Smithsonian Institution.)] [Illustration: STRINGFELLOW’S AËROPLANE (SIDE). (Courtesy Smithsonian Institution.)]