Although the historical reputation of Gottfried Wilhelm Leibniz (1646–1716) largely rests on his philosophical and mathematical work, it is widely known that he made important contributions to many of the emerging but still inchoate branches of natural science of his day. Among the many scientific papers Leibniz published during his lifetime are ones on the nascent science we now know as hydrology. While Leibniz’s other scientific work has become of increasing interest to scholars in recent years, his thinking about (...) hydrology has been neglected, despite being relatively broad in extent, including as it does papers on the ‘raising of vapours’ and the formation of ice, as well as the separation of salt and fresh water. That list can now be extended still further following the discovery of a previously unpublished letter of Leibniz’s on the causes of the devastating Lombardy flood of October and November 1705. This letter, which will be the focus of our paper, reveals the depth of Leibniz’s understanding of key hydrological processes. In it, he considers various mechanisms for the flood, such as heavy rains on high ground, underwater earthquakes, and a mountain collapse. Over the course of the paper we examine each of these mechanisms in depth, and show that Leibniz was in the vanguard of hydrological thinking. We also show that the letter contains one of the first scholarly attempts to apply aspects of the still-forming notion of the hydrological cycle to account for a flood event. (shrink)

Darcy's law is a phenomenological relationship for fluid flow rate that finds one of its principle applications in hydrology. Theoretical hydrologists rely upon a multiplicity of conceptual models to carry out approximate derivations of Darcy's law. These derivations provide structural explanations of the law; they require the application of fundamental principles, such as conservation of momentum, to idealized models of the porous media within which the flow occurs. In practice, recognition of the idealized conditions incorporated into models facilitates the (...) empirical clarification of the domain within which the law remains accurate. Structural explanations also contribute to the physical interpretation of phenomenological parameters. (shrink)

In recent decades, the use of electrochemistry has increased exponentially. Electrochemistry has demonstrated their effectiveness in the cleaning of manufactured effluents and the decomposition of complex hydrological compounds for water treatment. Looking at the efficiency of the technology in the decomposition of organic matter, one wonders if it is not capable of doing more than just the de-pollution and treatment of water. Of course, there are other uses of electrochemistry, but in the literature, it is understood that it is used (...) more for water treatment and de-pollution. This work is a review of the literature to identify the major works in electrochemical decomposition of organic matter to see to what extent this technology can be used for methane production (cooking gas) using pasty organic matter. The list of works appearing in this review is not exhaustive, but it is sufficient to give a clear idea of the technology, its progress and, above all, the challenges it faces. This review opens the way to other applications of electrochemical decomposition to meet today's energy challenges. (shrink)

We separate metaphysical from epistemic questions in the evaluation of models, taking into account the distinctive functions of models as opposed to theories. The examples a\are very varied.