"The biographers of Paine," wrote his friend, Joel Barlow, "should not forget his mathematical acquirements and his mechanical genius." But it would require a staff of specialists, and a large volume, to deal with Paine's scientific studies and contrivances--with his planing machine, his new crane, his smokeless candle, his wheel of concentric rim, his scheme for using gunpowder as a motor, above all his iron bridge. As for the bridge, Paine feels that it is a sort of American revolution carried into mechanics; his eagle cannot help spreading a little in the wondering eyes of the Old World. "Great scenes inspire great ideas," he writes to Sir George Staunton. "The natural mightiness of America expands the mind, and it partakes of the greatness it contemplates. Even the war, with all its evils, had some advantages. It energized invention and lessened the catalogue of impossibilities. At the conclusion of it every man returned to his home to repair the ravages it had occasioned, and to think of war no more. As one amongst thousands who had borne a share in that memorable revolution, I returned with them to the re-enjoyment of quiet life, and, that I might not be idle, undertook to construct a single arch for this river [Schuylkill]. Our beloved General had engaged in rendering another river, the Potowmac, navigable. The quantity of iron I had allowed in my plan for this arch was five hundred and twenty tons, to be distributed into thirteen ribs, in commemoration of the Thirteen United States." It is amusing after this to find Paine, in his patent, declaring his special license from "His Most Excellent Majesty King George the Third."* Had poor George been in his right senses, or ever heard of the invention, he might have suspected some connection between this insurrection of the iron age and the American "rebellion." However, Paine is successful in keeping America out of his specification, albeit a poetic touch appears. * "No. 1667. Specification of Thomas Paine. Constructing Arches. Vaulted Roofs, and Ceilings." The specification, dated August 28, 1788, declares his invention to be "on principles new and different to anything hitherto practised." The patents for England, Scotland, and Ireland were granted in September. An iron arch of one hundred feet was designed by Pritchard and erected by Darby at Coalbrook Dale, Shropshire, in 1779, but it did not anticipate the invention of Paine, as may be seen by the article on "Iron Bridges" in the Encyclopaedia Britannica, which also well remarks that Paine's "daring in engineering does full justice to the fervour of his political career." (Eighth edition; it is omitted in the ninth.)