By the mid nineteenth century fundamental advances were coming on
several fronts. The physician Jean Poiseuille (1799–1869) had accurately
measured flow in capillary tubes for multiple fluids, while in Germany
Gotthilf Hagen (1797–1884) had differentiated between laminar and turbulent
flow in pipes. In England, Lord Osborn Reynolds (1842–1912) continued
that work and developed the dimensionless number that bears his name.
Similarly, in parallel to the early work of Navier, George Stokes (1819–
1903) completed the general equations of fluid motion with friction that
take their names. William Froude (1810–1879) almost single-handedly
developed the procedures and proved the value of physical model testing.
American expertise had become equal to the Europeans as demonstrated by
James Francis’s (1815–1892) and Lester Pelton’s (1829–1908) pioneering
work in turbines and Clemens Herschel’s (1842–1930) invention of the Venturi
meter.