21To Thomas Jefferson from Oliver Evans, 9 December 1808 (Jefferson Papers)
...pay freely I Can say with truth that had all that used my improvements paid as generously as the President I might been enabled to render much greater services to my Country Boats propelled by my improved Steam Engines should have ascended the Mississippi before this day at a rate of 50 miles in 12 hours with good loads for it is a fact that they exert from five to ten times the power of the...