In 1678, a Frenchman named Besnier invented a flying-machine that is credited with being more successful than any hitherto attempted. His machine consisted of two bars of wood which were so hinged to a man's shoulders that they could be worked up and down by movements of the hands and feet. At the ends of these two bars were muslin wings made like shutters, so arranged that they were opened by a downward stroke and closed automatically by a reverse motion. The general appearance presented by these wings was that of four book-covers fastened by their backs to the ends of the bars, opening and closing alternately as the bars were worked up and down. The inventor began his experiments in a modest way. His first attempt at flight was by jumping from a chair; next he tried a table; and finally, emboldened by his success, he made flights from window-sills and even house-tops. On one occasion he is said to have sailed from his attic window over the roof of a neighboring cottage, alighting, without injury, some distance beyond. It was even rumored at one time that he would try to fly across the Seine, but if such a feat was ever contemplated, it was never attempted. Half a century later, however, the Marquis de Bacqueville actually made such an attempt with a machine somewhat similar to that of Besnier. The marquis had practiced in private with his machine with such encouraging results that he felt confident the feat was not an impossible one--in fact, that he was sure of accomplishing it. He therefore announced publicly that at a certain time the attempt would be made, and on the appointed day an immense crowd of people gathered on the banks of the river to witness the spectacle. Starting from a building some little distance away from the stream, the marquis made good progress at first, but just as he reached the river-bank his machine collapsed and he was tumbled out, alighting on a barge moored at the edge of the stream. Fortunately, the only injury he sustained was a broken leg; but this single attempt seems to have satisfied his aeronautic ambitions. Until this time all attempts made at aerial flight had been those in imitation of birds; but during the early part of the eighteenth century the idea of the balloon was developed. This was the result of the numerous important discoveries made about that time as to the qualities of the atmosphere, and also several other "airs," as gases were called, such as their expansion and contraction under different conditions of temperature.