 …the greatest part of the Ideas, that make our complex Idea of Gold, are Yellowness, great Weight, Ductility, Fusibility, and Solubility, in Aqua Regia, etc. all united together in an unknown Substratum; all which Ideas, are nothing else, but so many relations to other Substances; and are not really in the Gold, considered barely in it self, though they depend on those real, and primary Qualities of its internal constitution, whereby it has a fitness, differently to operate, and be operated on by several other Substances.