In 1797 Fulton went to Paris, where he resided seven years, as the terrors of the French Revolution were passing away. At this period he had invented what is now called a torpedo, largely used in modern warfare for the protection of harbors. He devised a submarine boat to operate these destructive weapons, which was not a success. He demonstrated what he claimed for the torpedo in the destruction of a brig of two hundred tons; but he failed to procure the adoption of this more modern engine of warfare by either France or England, and he had the honor to be snubbed by Napoleon I. In 1806 he returned to New York, where he labored for the recognition and introduction of the torpedo. He was encouraged by Jefferson and Madison, and Congress appropriated money for experiments; but the naval officers reported against him, and nothing came of his efforts. In Paris he had made the acquaintance of Chancellor Livingston, then the American minister to France, who was interested in Fulton's work, and who soon entered into business relations with him in connection with it. He was a man of abundant fortune, while the inventor was comparatively poor; occupied an elevated social position, and was a person of great influence. He obtained a grant of the monopoly of steam-navigation from the State of New York. Fulton took out two patents for his invention; but unfortunately they were not adequate to his protection, for they covered only the application of the steam-engine to the turning of a crank in producing the rotary motion of the paddle-wheels. While in England Fulton had contracted with Watt for the building of such an engine as he desired, without stating the purpose for which it was to be used. This engine reached New York at about the same time as the inventor. He made his plans for the construction of the boat, which was to be of different form and proportions from ordinary vessels, and it was completed and fitted out with its engine during the year following his return. Not long before this event, when he found the sum of money Mr. Livingston had provided to complete the steamboat was nearly exhausted, Fulton attempted to sell an interest in his exclusive grant in order to raise funds to supply the deficiency; but so little faith existed in the success of his enterprise that he could find no one who had the courage to purchase it. But the vessel was finished, and a trial trip was made in her, to which gentlemen of science and general intelligence were invited, most of them, like the rest of the world, sceptics and unbelievers. A few minutes served to satisfy these men that the steamboat was a success, and that the problem of steam-navigation had been solved in its favor. It was the hour of Fulton's triumph.