The Development of Newton's Theory of Color

Abstract

TO perform my late promise to you, I shall without further ceremony acquaint you, that in the beginning of the Year 1666 (at which time I applyed my self to the grinding of Optick glasses of other figures than Spherical,) I procured me a Triangular glass-Prisme, to try therewith the celebrated Phaenomena of Colours. 1 Thus Isaac Newton, introducing his first paper on light, introduced himself to the scientific world of his day. If the words, as introduction, lead us to look forward, not only to his work in optics, but to the entire career which would see him in the end enthroned as reigning monarch over British science, so also they look backward toward a long tradition of optical research and speculation. The phenomena of colors were, as Newton said, celebrated. When he darkened his chamber to play a spectrum against the wall opposite the window, however, he was not, as the words might be taken to imply, repeating an experiment established in optical tradition. Newton's experiment differed, deliberately, in crucial factors from any that the tradition presented to him. Indeed it was designed to overthrow the received doctrine of colors which the tradition, tracing its descent back some two thousand years, had delivered to him. The planning of the experiment, not its observed results, constituted the revolution in the theory of colors. The mechanistic philosophy established as the foundation of seventeenth century science by Descartes set the context of Newton's investigation and provided the immediate complex of ideas that his work in optics overturned. The phenomena of light and colors had acquired new significance in the eyes of Descartes and of those following him who saw in the mechanical philosophy the key to the riddles of nature. When Descartes argued that light distinguishes the three basic elements or orders of corpuscles from which res extensae are composed, so that bodies are either luminous, transparent, or opaque, he could not fail to be interested in optics.2 The phenomena of colors, moreover, took on major importance in his attack on Aristotelian real qualities. If we say that we see color in a body, Descartes asserted, it is the same as saying that we see something but are absolutely ignorant as to its nature. We are utterly unable to conceive what it could