. American engineer and railroad journal . 500,and we may add that a sketch has been found in his notebooks for a proposed aerial screw machine 96 ft. in diame-ter to be built of iron and bamboo framework, coveredwith linen cloth thoroughly starched. He probably aban-doned all idea of constructing it when his experimentswith models showed the power that would be required. A similar proposal was made by Paucton, a learnedmathematician, in 1768, when, in a treatise upon theArchimedean screw, he described an apparatus which hecalled a Ilerophore, consisting of two aerial screws,one to sustain and
. American engineer and railroad journal . 500,and we may add that a sketch has been found in his notebooks for a proposed aerial screw machine 96 ft. in diame-ter to be built of iron and bamboo framework, coveredwith linen cloth thoroughly starched. He probably aban-doned all idea of constructing it when his experimentswith models showed the power that would be required. A similar proposal was made by Paucton, a learnedmathematician, in 1768, when, in a treatise upon theArchimedean screw, he described an apparatus which hecalled a Ilerophore, consisting of two aerial screws,one to sustain and the other to propel, attached to a lightchair. A man seated in the chair was expected to rotatethese screws by means of gearing, and so raise himselfthrough the air. The first practical experiment known, however, is thatof M Launoy, a naturalist, and M. Bienvcnu, a mechani-cian, who jointly exhibited before the Irench Academy ofSciences in 1784 the little apparatus shown in fig. 25. Itconsisted of two superposed screws, about one foot in. Fig. 25.—launoy & BIENVENU—1784. diameter, each composed of four feathers inserted insockets at the ends ot a rotating axle. This axle was putinto motion by the unwinding of a cord fastened to thetwo extremities of a bow ; and the report to the FrenchAcademy (May i, 1784) says : The working of this machine is very simple. Whenthe bow has been bent by winding the cord, and the axleplaced in the desired direction of flight—say vertically, forinstance —the machine is released. The unbending bowrotates rapidly, the upper wings one way and the lowerwings the other way, these wings being arranged so thatthe horizontal percussions of the air neutralize each other,and the vertical percussions combine to raise the therefore rises and falls back afterward from its ownweight. Launoy & Bienvenu proposed also to build a largemachine, and to go up in it themselves. It is not staledwhether this was ever attempted ; but probably not, as ab
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