Upon reaching Paris, he took up his residence with Mr. Joel Barlow, and thus was laid the foundation of a friendship between these two gentlemen which lasted during their lives. He remained in Paris seven years, residing during that time with Mr. Barlow, and devoting himself to the study of modern languages, and engineering and its kindred sciences. His work was continuous and severe in Paris. He invented and painted the first panorama ever exhibited in that city, which he sold for the purpose of raising money for his experiments in steam navigation; he also designed a series of splendid colored illustrations for _The Columbiad_, the famous poem of his friend Mr. Barlow. Besides these, he invented a number of improvements in canals, aqueducts, inclined planes, boats, and guns, which yielded him considerable credit, but very little profit. In 1801, he invented a submarine boat which he called the "Nautilus," which is thus described by M. de St. Aubin, a member of the Tribunate: "The diving-boat, in the construction of which he is now employed, will be capacious enough to contain eight men and provision for twenty days, and will be of sufficient strength and power to enable him to plunge one hundred feet under water, if necessary. He has contrived a reservoir of air, which will enable eight men to remain under water eight hours. When the boat is above water, it has two sails, and looks just like a common boat; when it is to dive, the mast and sails are struck. "In making his experiments, Mr. Fulton not only remained a whole hour under water, with three of his companions, but had the boat parallel to the horizon at any given distance. He proved that the compass points as correctly under water as on the surface, and that while under water the boat made way at the rate of half a league an hour, by means contrived for that purpose. "It is not twenty years since all Europe was astonished at the first ascension of men in balloons: perhaps in a few years they will not be less surprised to see a flotilla of diving-boats, which, on a given signal, shall, to avoid the pursuit of an enemy, plunge under water, and rise again several leagues from the place where they descended! "But if we have not succeeded in steering the balloon, and even were it impossible to attain that object, the case is different with the diving-boat, which can be conducted under water in the same manner as upon the surface. It has the advantage of sailing like the common boat, and also of diving when it is pursued. With these qualities, it is fit for carrying secret orders, to succor a blockaded fort, and to examine the force and position of an enemy in their harbors."