Epicurus... supposes not only all mixt bodies, but all others to be produced by the various and casual occursions of atoms, moving themselves to and … - Robert Boyle

And of universal nature, the notion I would offer, should be something like this. Nature is the aggregate of the bodies, that make up the world, in its present state, considered as a principle, by virtue whereof, they act and suffer, according to the laws of motion, prescribed by the author of things.

For it very rarely otherwise happens, than that theories, that are grounded but upon few and obvious experiments, are subject to be contradicted by some such instances, as more free and diligent inquiries into what of nature is more abstruse, or even into the less obvious qualities of things, are wont to bring to light.

There are some mixt bodies, from which it has not been yet made appear, that any degree of fire can separate either salt, or sulphur, or mercury, much less all the three. The most obvious instance of this truth is gold, which is a body so fixed, and wherein the elementary ingredients (if it have any) are so firmly united to each other, that we find not in the operations, wherein gold is exposed to the fire, how violent soever, that it does discernably so much as lose of its fixedness or weight, so far is it from being dissipated into those principles, whereof one at least is acknowledged to be fugitive enough.