Until Israel Gregg came along, steamboat commerce on the Ohio river was considered impractical, largely because the currents were so strong.

But Gregg had an interesting approach to demonstrate that it was, in fact, possible. In some portions of the river, there was a confluence with another river, which meant that there were multiple currents in the river for some distance. This is what made it hazardous in the first place.

Gregg made a point of seeking out the currents of a specific river in each confluence, and navigating only that river’s current. So from Brownsville to Pittsburgh, Gregg used the currents of the Monongahela River. From Pittsburgh to Cincinnati, he used the currents of the Ohio River. Then he remained with the current of the Ohio to Louisville. From there he returned to Pittsburgh, running against the current of the Ohio. A few cycles of this had people convinced, and his ship, the Enterprise, became one of the first of that name to go down in history. (Specifically, it was the third in American history.)