 Atomic theories became common in the seventeenth century. The emerging emphasis on experiment led the proponents of those theories to become less concerned with philosophical systems and more concerned with the explanation of specific phenomena such as condensation and rarefaction, evaporation, the strength of materials and chemical change. There was an increasing tendency for atomists to borrow in an opportunist way from both the mechanical and natural minima traditions as well as from the alchemical tradition which employed atomistic theories of its own as Newman (1991, 143–190 and 1994, 92–114) has documented. Thus an Aristotelian proponent of the natural minima tradition, Daniel Sennert, whose main interest was in chemistry in medical contexts, drew on the work of the alchemists as well as that of the minima theorists, employed minima in physical as well as chemical contexts, and insisted that his atomism had much in common with that of Democritus (Clericuzio, 2000, 23–29 and Melsen, 1952, 81–89). Boyle referred to his mechanical atoms as natural minima and his first account of atomism involved attributing to an atom properties distinctive of the substance it was a least part of (Newman, 2006, 162ff, Clericuzio, 2000, 166ff) and in fact borrowed heavily from Sennert (Newman, 1996). In subsequent writings he made it clear that in his view least parts of substances are composed of more elementary particles possessing only shape, size and a degree of motion. Whether, according to Boyle, properties other than primary mechanical ones emerge at the level of least parts or at the macroscopic level is an issue on which contemporary commentators disagree (Chalmers, 2009, 155–161), Chalmers, 2010, 8–9, Clericuzio, 2000, 103–148, Newman, 2006, 179–189). The theories of a number of atomists, such as Sebastien Basso, Etienne de Clave and Thomas Digges, were an eclectic mixture of ingredients drawn from mechanical atomism, minima theory and alchemy. (Clericuzio, 2000, Melsen, 1952, Newman, 2006)