In the later seventeenth century the term experimental philosophy became voguish in England, among the Fellows of the Royal Society and especially in the subsequent usage of Isaac Newton. The latter's adoption of the term ensured its longevity and its adoption elsewhere, and coupled experimental manipulations with mathematical formalisms and analysis. Newton's first publication, in 1672, displayed such an approach even before Newton adopted the term itself, but it nicely displays Newton's approach. Qualitative experimental approaches to phenomena of colours, augmented by simple measurements and geometrical inferences, are presented in such a way as to create the ­impression that substantive conclusions can be drawn about the phenomena under examination. This chapter elaborates on mathematical ideas cloaked in Baconian descriptions. The initial historical narration sets up the chapter as an only-somewhat mathematised version of a Baconian experiment. Newton continues with a discussion that takes a more formalised mathematical approach.