 The analysis of compounds to ingredients, followed in the Opticks, looks for parts, components, constituents etc., and accompanies the mathematical methods of analysis where they prove to be inadequate in themselves. The qualitative component of analysis is intended to reveal the composition of optical and, especially in the Queries, chemical phenomena. The paradigmatic cases are, of course, Newton’s prism experiments that revealed the composition of white light. In the first two books of the Opticks Newton himself uses the method of analysis of compounds into ingredients “to discover and prove the original differences of rays of light” (Query 31, Newton 2004: 140), that is to discover qualitative differences that persist due to the lack of their analysis in the “Newtonian style”. Most notable among them, as the experimentum crucis had revealed, are colours that 