In "Astra Castra," we read that soon after Bacon's time, projects were instituted to train up children in the exercise of flying with artificial wings, and considerable progress was made; by the combined effort of running and flying they were enabled to skim over the surface, as it were, with incredible speed. This same Roger Bacon, an eminent philosopher of the thirteenth century, and possessed of the very highest genius and ability, whose ideas and knowledge, like Franklin's, were many hundred years ahead of his age, descants, in one of his works, in glowing language, on the practicability of constructing engines that could navigate the air. He accomplished wonderful things in his day, and was accused of holding communion with the devil, who was quite an important personage in those times. His writings were interdicted, and himself locked up to prevent closer acquaintanceship of his readers with the aforesaid friend. About the Confessor's time, a monk, Elmirus, in Spain, flew often, by means of a pair of wings, many miles from high elevations. Cuperus, in his treatise on "The Excellency of Man," contends that it is practicable for human beings to attain the faculty of flying. He asserts that Leonardo da Vinci, the great painter of the "Lord's Supper," and other highly prized works of art, practiced it successfully. The reasoning of the great John Wilkins, Lord Bishop of Chester, who died in 1672, embodies the sentiments and principles of all these on the subject even stronger. In his work on "Mechanical Motion," he treats expressly on artificial flight, and conceives, in the sixth chapter, the framing of such "volitant automata" very easy; and says that the time will come when men will call for their wings when about to make a journey, as they do now for their boots and spurs. Lastly, in the "Journal de Savans," of the 12th of September, 1678, an account is given of one Besnier, a locksmith of Sable, France, who succeeded in flying. But as his machine was extremely primitive--the wings consisting only of four rectangular surfaces, one at the end of each of two poles, which passed over the shoulder of the operator, and were worked alternately up and down--the inventor could only avail himself of their aid in progressively raising himself from one hight to another, until an elevated position was reached, when he could glide through the air a long distance.