There were inventions, of course, among them a marble-sawing machine, a flax-spinning engine, a rope-making machine and a mechanical dredger. But the steamboat, the submarine and the torpedo, with all of which he is frequently credited, had their origins in other men's minds.
The steamboat, in particular, was an established fact - both in Europe and America - long before the young, New England portrait painter came on the scene.
Yet although Fulton did not actually come up with the original idea of marrying the steam-engine to the river boat - there is some evidence that he even sailed on the earlier steamboats of William Symington in Britain - he must take the credit for making the plan work commercially.
His Clermont made its maiden voyage between New York City and Albany in 1807, taking 22 hours over the journey, and proved an immediate success with fare-paying passengers. His vision led directly to the heroic steamboat era of America's expansion.
Robert Fulton was born in a farmstead at Little Britain, in Pennsylvania's Lancaster County, on November 14th, 1765.
Conventional schooling failed to inspire the youngster, but his inventive brain was already producing a stream of ideas. He made his own lead pencils that were reputedly better than those that could be bought at the local store, produced a rifle of an original design and a hand-operated paddle wheel, and also turned his hand to making household utensils.
Fulton was apprenticed to a Philadelphia jeweller at the age of 17, but his early talent lay in the world of art and he began to establish a reputation as a painter of miniature portraits. He was successful enough to save the money to buy his mother a farm before he was 21.
At that point, he sailed to England to study with the prominent American portrait painter Benjamin West, and a whole new chapter of his life opened.
In England, he became friendly with the Duke of Bridgewater, whose canal linking his coalmines at Worsley and the centre of Manchester had begun the frantic era of canal building in Britain.
Fulton caught the canal bug just as the 1790s saw a frenzied canal-building period in America. In 1796, he wrote a treatise on canal construction, suggesting improvements to locks and other features, and sent copies home to George Washington, who had already had a distinguished career as a canal surveyor, and to Pennsylvania's state governor.
By 1797, however, Fulton had moved from England to France and switched his interest from civil engineering to military matters. His early experiments with "automobile torpedoes" were unsuccessful, but he worked on, spurred by his own interesting theories on the importance of international trade.
He felt that British naval oppression had to be halted, because freedom of the seas was vital to every nation.
His belief led him to develop a submarine and a method of using it - what would today be termed a weapons system - and he went to France in an effort to interest the revolutionary government.
The Directory, however, refused to have anything to do with the idea, and it was not until Napoleon came to power that the possibilities were realised.
Fulton built a "diving boat" in the winter of 1800-01 and showed it off to French experts that summer. The Nautilus was not the world's first submarine - American David Bushnell had built and operated a one-man sub during the War of Independence. But Fulton's boat worked pefectly, with a primitive compressed-air system allowing the four-man crew to stay under water for an hour. It prowled Brest harbour all that summer, even sinking a ship that Napoleon had put at Fulton's disposal.
They listened to his ideas, but were not convinced. Fulton attempted to persuade them by fitting out an expedition against the French fleet in Boulogne, using surface boats and torpedoes - what Fulton termed 'torpedoes', however, were, in fact, mines that were dropped beneath the hull of the target.
When this scheme failed, largely because of the inexperience of his operatives, he carried out a spectacular demonstration by sinking a brig in Walmer Roads, near Deal, on October 15th, 1805, under the walls of the castle belonging to Prime Minister William Pitt.
Even this was not enough to alter the British attitude, and with negotiations with both the British and French getting nowhere, Fulton rapidly lost interest in the whole idea.
The American's willingness to deal with two countries who were the greatest of enemies may sguggest he was motivated simply by greed and was ready to sell out to the highest bidder. But this was not true - or so he said. His dream, he claimed, was to open up the seas to everyone, and he believed that this could be achieved only by making naval warfare impossible. His submarine and torpedo, he felt, could achieve this, and he was not particular about which side used them.
Was Henry the first?SOME people believe that the credit for building the first steamboat in America goes not to Robert Fulton, nor even to John Fitch but to the little-known William Henry.
The son of an Irish immigrant living in Lancaster, Pennsylvania, reputedly sailed his paddle-wheel steamer on the Canastoga River near his home in Lancaster, Pennsylvania, in 1763.
The boat is said to have sunk after an accident, but he built another.
But there is a lot of confusion about Henry's story. For instance, he is supposed to have gained his knowledge of the steam engine from a visit to England in 1760 and talks with James Watt.But Watt did not even begin to think about steam engines until 1763, and it was many years later that he perfected his ideas. However, Henry must have known something about the steam business. In later years, the youthful Fulton and Fitch - both near neighbours - were visitors to his home.
Henry's engine was supposedly still in existence in 1783, but he appears to have given up the idea of steamboats, telling a visitor:
"I am doubtful if such a machine would find favour with the public, as everyone considers it impracticable to make a boat move against wind or tide."