The rapid increase of knowledge in the field of hydrology during the nineteenth century is indeed remarkable. The experimental methods, that were successfully pioneered by Perrault, Mariotte and Halley in the seventeenth century had already taken firm roots, and, undoubtedly, the major developments during the nineteenth century were in the fields of ground water hydrology and surface water measurements. At the beginning of the century, the French School was still the leading one in the field of hydrology and hydraulics, but it had a rather bad experience due to the French Revolution. The Revolutionary Government suspended the Académie des Sciences in 1793, executed scientists like Lavoisier, Bailly and Cousin, and drove Condorcet to suicide. Fortunately for science, the authorities quickly realized their mistakes. Men like Du Buat, who had to flee from France to save his life, later returned to their native land, and continued to carry on their admirable work.
By Asit K. Biswas, Chapter 13 of the book: History of Hydrology, 1970, North-Holland Publishing, Amsterdam.