After one or two trips had proved its usefulness, the possessors of the monopoly became alarmed and began proceedings against the new rival.

Driven from the waters about New York, Stevens took his boat around to Philadelphia.

Thus not only did he open an entirely new field of river and inland water transportation, but the trip to Philadelphia demonstrated the entire practicability of steam for use in coastwise navigation.

Thereafter the vessels multiplied rapidly on all American waters.

Fulton himself set up a shipyard, in which he built steam ferries, river and coastwise steamboats.
In 1809 he associated himself with Nicholas J.Roosevelt, to whom credit is due for the invention of the vertical paddle-wheel, in a partnership for the purpose of putting steamboats on the great rivers of the Mississippi Valley, and in 1811 the "New Orleans" was built and navigated by Roosevelt himself, from Pittsburg to the city at the mouth of the Mississippi.