This chapter treats the emergence of a language of physics loosely unified on a mechanistic basis. The early studies of thermal and electrical phenomena were in the Baconian tradition of exploring nature and relying on informal inductive arguments. Laplace transformed the earlier mechanistic atomism, which accorded philosophical arguments concerning atoms a foundational role, into atomistic mechanism. This gave mechanics a foundational role and introduced testable hypotheses concerning atoms and short-range forces. Atomistic mechanism facilitated the incorporation of the Baconian sciences. This supplied a perspective for a meaningful distinction between depth and relatively phenomenological accounts and facilitated the incorporation and interpretation of the new sciences of thermodynamics and electrodynamics.