Pierre Perrault - circa 1608 (Paris, France) – 1680 (Paris, France )
Pierre Perrault was a Receiver General of Finances for Paris and later a scientist who developed the concept of the hydrological cycle. He and Edme Mariotte were primarily responsible for making hydrology an experimental science. Perrault grew up in a bourgeois family, had at least seven siblings, and probably lived all his life in Paris. Little is known about his life, despite the fame of some of his younger brothers. These include Claude, an architect of part of the Louvre Palace; Nicholas, a doctor of theology known for his denunciation of the Jesuits; and Charles, author of Tales of Mother Goose.
Perrault was trained as a lawyer, and in 1654 purchased the position of Receiver General of Finances for Paris. This post involved collecting taxes for Louis XIV, and he received a percentage of the taxes he collected. This position ruined him when Louis XIV chose to calm rebellious taxpayers by granting a remission of all taxes that were still owed after 10 years. Pierre had used some of his tax receipts for 1664 to pay creditors, and when he could not deliver the money to the royal treasury, he was forced into bankruptcy.
After the bankruptcy Perrault became an amateur scientist and focused his attention on the origin of springs. The result of his labor was his book de l'Origine des fontaines (On the Origin of Springs), published anonymously in 1674 and dedicated to his friend Christiaan Huygens.
In the millennia before Perrault published his book on the Origins of Springs, most natural philosophers asserted that there was not enough precipitation to account for the flow in rivers and springs. Aristotle claimed that most of the water came from underground caverns in which air was transformed into water. Many others argued that seawater entered underground caverns, was heated until it rose as vapor, then condensed and fed springs, which in turn fed rivers. Although some philosophers such as Anaxagoras had more realistic models of the hydrologic cycle, the weight of authority was behind the more fanciful theories.
Perrault devoted the first part of his book, On the Origin of Springs, to analyzing the ideas of his predecessors and what he called the "Common Opinion", rejecting most of it. He estimated the flow in the Seine River and compared it with rainfall in the watershed, showing that the rainfall was easily enough to account for the flow in the river. This conclusion was later supported by a more rigorous quantitative analysis published by Edme Mariotte.
With a series of experiments, Perrault showed that rain does not penetrate the soil beyond about 2 feet. Thus, most of the rain that falls does not go into springs. Perrault went on to develop the theory of the hydrologic cycle, correctly accounting for the roles of evaporation, transpiration, throughflow and surface runoff.
Perrault was aware that his methods were crude andhis estimates approximate. Nevertheless, he argued thateven imprecise measurements were superior to the verbal method of argumentation employed in Aristotelean naturalphilosophy. “I know very well that this deduction hasno certainty ...[but] it is more satisfactory than a simplenegative like Aristotle’s”
There was thus an unresolved problem in Perrault’s theory: he was not able to discern the route by whichinfiltration occurred. He rejected “universal and uniformpenetration” (1967, 84), and speculated waters perhaps“go underground through some gravely and permeablespot” (1967, 101). Perrault shrugged off the problem,concluding “whatever the way in which waters of rainsand melted snows enter rivers, I do not care, having noother interest but to see the rivers swelled by these watersin whatever way it may be” (1967, 101 to 102).
Perrault’s conception of stratigraphy was necessarily primitive. He envisaged the presence of a “continuous and universal bed of clay” overlain by “much pure sand ...mixed with pebbles of all sizes” (Perrault 1967,100). Rivers were underlain by this clay layer, and the presence of the impermeable clay “prevents them from sinking lower” (Perrault 1967, 100).
Nace, Raymond L. (1974). "Pierre Perrault: The man and his contribution to modern hydrology". Journal of the American Water Resources Association. 10 (4): 633–647. doi:10.1111/j.1752-1688.1974.tb05623.x.
Deeming, David, 2014, Pierre Perrault, the Hydrologic Cycle and the Scientific Revolution, Groundwater, 52(1), 156-162
Biswas, A K, 1970, History of Hydrology, North-Holland, Amsterdam
Perrault, Pierre (1967). On the origin of springs. Translation of "De l’origine des fontaines” (1674) by A. LaRocque. Hafner. ASIN B0026MBIHE. download