steamboats steamboats steamboats steamboats steamboats steamboats ticket koste 3 dollar first practical steamboat Robert Fulton 4 steamboats first practical steamboat steamboats steamboats steamboats first steamboat line Fulton's First Steamboat Voyage, 1807 steamboats steamboats first practical steamboat Fulton's First Steamboat Voyage, 1807 steamboats steamboats steamboats steamboats Clermont steamboats