The life of Sir Isaac Newton Author:George Grant Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER IV. New Classification of Colours. Outline of a New Theory. Newton's Discoverics respecting the Inflexion or Diffraction of Light. Previous Discoveric... more »s. Labours of succeeding Philosophers. New Theory of Inflexion. Miscellaneous Optical Researches of Newton. Experiments on Refraction. Conjecture respecting the Inflammability of the Diamond. Law of Double Refraction. Observations on the Polarization of Light. Newton's Theory of Light. His " Optics." Astronomical Discoverics. Sketch of the History of Astronomy previous to the time of Newton. Whatever answer may be made to the previous objections, we think it will be admitted by all those who have studied the subject most profoundly, that a satisfactory theory of the colours of natural bodies is still a desideratum in science. How far we may be able to approach it in the present state-of optics, the reader will judge from the following views. Colours may be arranged into seven classes, each of which depends upon different principles. 1. Transparent coloured fluids—transparent coloured gems—transparent coloured glasses—coloured powders—and the colours of the leaves and flowers of plants. 2. Oxidations of metals—colours of Labrador feld-spar—colours of precious and hydrophanous opal, and other opal essences—the colours of the feathers of birds, of the wings of insects, and of the scales of fishes. 3. Superficial colours, as those of mother of pearl and striated surfaces. 4. Opal essences and colours in composite crystals having double refractions. 5. Colours from the absorption of common and polarized light by double refracting crystals. 6. Colours at the surfaces of media of different dispersive powers. 7. Colours at the surface of media in which the reflecting forces extend to different distances,...« less