The title essay, along with other papers in this volume, laid the foundation of modern thermodynamics. Highly readable, "Reflections" contains no arguments that depend on calculus, examining the relation between heat and work in terms of heat in steam engines, air-engines, and an internal combustion machine. Translation of 1890 edition.
Here's a sample of other books in this Dover category
The Analytical Theory of Heat by Joseph Fourier Landmark publication that first showed how any discontinuous function could be represented by a trigonometric series and advanced many other concepts of modern mathematical physics, in unabridged 1878 Freeman translation
