The Timaeus is the dialogue that was for many centuries the most influential of Plato’s works. Among its readers we find Descartes, Boyle, Kepler and Heisenberg. In the first division of Timaeus Plato deals with the theory of celestial motion, in the second he presents us with the first mathematical theory of the structure of matter. Here, in a gigantic step forward with respect to the preceding Democritean atomistic theory with its unalterable micro-entities, he introduces the intertransformability of elementary corpuscles (...) and with that the first “chemical” reactions in history. Plato’s geometrical interpretation of Empedocles’ elements and his geometrical atomism is described at the molecular, atomic and sub-atomic level. The “chemical” reactions reported in Timaeus are written in the enlightening chemical symbolism, analogies with modern chemistry are noticed throughout. (shrink)