Having obtained a patent for mill improvements from the British Government, he went to France with the intention of introducing his invention there; but, not meeting with much encouragement, he devoted his time to other matters. Political economy had also some attraction for him, and he wrote a book to show that internal improvements would have a good effect on the happiness of a nation. He not only wished to see a free and speedy communication between the different parts of a large country, but universal free trade between all countries. He thought that it would take ages to establish the freedom of the seas by the common consent of nations, and believed in destroying ships of war, so as to put it out of the power of any nation to control ocean trade. In 1797 he became acquainted with Joel Barlow, the well-known American, then residing in Paris, in whose family he lived for seven years, during which time he learned French and something of German, and studied mathematics and chemistry. In the same year he made an experiment with Mr. Barlow on the Seine with a machine he had constructed to give packages of gunpowder a progressive motion under water and then to explode at a given point. These experiments appear to have been the first in the line of his submarine boats, and are unquestionably the germ of all subsequent inventions in the direction of torpedo warfare. Want of money to carry out his designs induced him to apply to the French Directory, who at first gave him reason to expect their aid, but finally rejected his plan. Fulton, however, was not to be discouraged, but went on with his inventions, and having made a handsome model of his machine for destroying ships, a commission was appointed to examine his plans, but they also rejected them. He offered his idea to the British Government, still again without success, although a committee was appointed to examine his models. The French Government being changed, and Bonaparte having come to the head of it, Fulton presented an address to him. A commission was appointed, and some assistance given which enabled him to put some of his plans into practice. In the spring of 1801 he went to Brest to make experiments with the plunging boat that he had constructed in the winter. This, as he says, had many imperfections, to be expected in a first machine, and had been injured by rust, as parts which should have been of copper or brass were made of iron.