The Jonval turbine is a water turbine design invented in France in 1837 and introduced to the United States around 1850 and were widely used. The Jonval turbine is a "mixed-flow" turbine design. Mixed-flow designs were well suited for the low-head applications common in the eastern United States. The smaller size, higher speed, higher power, lower cost, and ability to operate efficiently with variable water levels caused these and other types of hydraulic turbines to replace the vertical waterwheel as the primary source of power in American industries.