2024 Key Reflections on the 1824 Sadi Carnot’s “Réflexions”

This author is not a philosopher nor historian of science, but an engineering thermodynamicist. In that regard and in addition to various philosophical why how treatises and existing historical analyses, the physical and logical what it is reflections, as successive Key Points, where a key reasoning infers the next one, along with novel contributions and original generalizations, are presented. We need to keep in mind that in Sadi Carnots time (early 1800s) the steam engines were inefficient (below 5%, so the heat in and out were comparable within experimental uncertainty), the conservation of caloric flourished (might be a fortunate misconception), and many critical thermal-concepts, including the conservation of energy (The First Law) were not even established. If Clausius and Kelvin were "fathers of thermodynamics" then Sadi Carnot was the "grandfather" Kostic, 2023 July 24, or better yet, Sadi Carnot was the "Forefather of Thermodynamics-to-become" Kostic, 2023 October 29.