 Robert Boyle (1627–1691) is often credited with first breaking with ancient and medieval traditions and inaugurating modern chemistry by fusing an experimental approach with mechanical philosophy. Boyle’s chemical theory attempts to explain the diversity of substances, including the elements, in terms of variations of shape and size and mechanical arrangements of what would now be called sub-atomic atoms or corpuscles. Although Boyle’s celebrated experimental work attempted to respond to Aristotelian orthodoxy, his theorizing about atoms had little impact on his experimental work. Chalmers (1993, 2002) documents the total absence of any connection between Boyle’s atomic speculations and his experimental work on the effects of pressure on gases. This analysis applies equally to Boyle’s chemical experiments and chemical theorizing, which was primarily driven by a desire to give a mechanical philosophy of chemical combination (Chalmers 2009, Ch. 6). No less a commentator than Antoine Lavoisier (1743–1794) was quite clear that Boyle’s corpuscular theories did nothing to advance chemistry. As he noted towards the end of the next century, “… if, by the term elements, we mean to express those simple and indivisible atoms of which matter is composed, it is extremely probable we know nothing at all about them” (1789, p. xxiv). Many commentators thus regard Boyle’s empirically-based criticisms of the Aristotelian chemists more important than his own atomic theories.