By rational mechanics is meant the development of the subject of Mechanics according to a strict logical scheme, proceeding, like Geometry, from certain hypotheses or axioms established (or indicated) by experiment, from which particular theorems or applications are deduced. Every branch of theoretical physics aims at such a complete rational treatment, but whereas in Geometry the axioms have long ago been classified and isolated, and the bulk of the science consists of the deductions from them, in Physics we are still largely occupied with the discovery of the laws and axioms.