1611-1680

French hydrologist whose De l'origine des fontaines (1674) is one of the foundational works in experimental hydrology. Perrault demonstrated rainfall is sufficient to maintain the flow of rivers. He determined the drainage area for a portion of the Seine River and calculated the total precipitation. After adjusting for losses, he compared the total volume of water with the river's annual flow and showed that only one-sixth of the annual rainfall was necessary to sustain it.