Trafalgar was the greatest fight of the sailing-ships. There were later engagements which were fought under sail, but no battle of such decisive import. It was a fitting close to a heroic era in the history of naval war, a period of not much more than four centuries, in thousands of years. Before it, came the long ages in which the fighting-ship depended more upon the oar than the sail, or on the oar exclusively. After it, came our present epoch of machine-propelled warships, bringing with it wide-sweeping changes in construction, armament, and naval tactics. Inventive pioneers were busy with projects for the coming revolution in naval war while Nelson was still living. The Irish-American engineer, Fulton, had tried to persuade Napoleon to adopt steam propulsion, and had astonished the Parisians by showing them his little steamer making its way up the Seine with clumsy paddles churning up the waters and much sooty smoke pouring from its tall, thin funnel. The Emperor thought it was a scientific toy. Old admirals--most conservative of men--declared that a gunboat with a few long "sweeps" or oars would be a handier fighting-ship in a calm, and if there was any wind a spread of sail was better than all the American's tea-kettle devices. Fulton went back to America to run passenger steamers on the Hudson, and tell unbelieving commodores and captains that the future of the sea power lay with the "tea-kettle ships." In the days of the long peace that followed Waterloo, and the great industrial development that came with it, the steam-engine and the paddle-steamer made their way into the commercial fleets of the world, slowly and timidly at first, for it was a long time before a steamship could be provided with enough efficient engine power to enable her to show the way to a smart clipper-built sailing-ship, and the early marine engines were fearfully uneconomical. Steam had obtained a recognized position in small ships for short voyages, ferry-boats, river steamers, and coasting craft, but on the open ocean the sailing-ship still held its own. An eminent scientist proved to demonstration that no steamship would ever be able to cross the Atlantic under steam alone. He showed that to do so it would be necessary for her to carry a quantity of coal exceeding her entire tonnage capacity, and he expressed his readiness to eat the first steamer that made the voyage from Liverpool to New York. But he lived to regret his offer.