Brunswick Green, Chrome Green, Copper Greens, Verdigris, Scheele's Green, Emerald Green, Mineral Green, Green Verditer, Bremen Green, Terre Verte, Cobalt Green, Ultramarine, Natural Ultramarine, Artificial Ultramarine, Manu- facture of Ultramarine, Properties of Ultramarine, Com- position of Ultramarine, Constitution of Ultramarine; Assay and Analysis; Ultramarine Derivatives, Violet Ultramarine, Red Ultramarine; Prussian Blues, Chinese Blue, Soluble Blue, Antwerp Blue, Brunswick Blue, Properties of Prussian Blues, Assay and Analysis of Prussian Blues; Cobalt Blues; Smalts, Manufacture of Smalts, Composition and Properties of Smalts, Assay and Analysis of Smalts; Cobalt Blue, Properties and Composition of Cobalt Blue, Assay and Analysis of Cobalt Blue; Copper Blues, Mountain Blue, Umber, Composition and Properties of Umbers, Assay and Analysis Lamp and Vegetable Blacks, Properties and Composition of Lamp- Properties and Composition of Bone-Black, Assay and PAGES Red Lakes, Carmine, Carmine Lake, Florentine Lake, Brazil-Wood Lakes; Rose Pink, Red Lake, Yellow Lakes, Orange Lake, Madder Lakes, Madder Red Lakes, Green Lakes, Violet Lake; Analysis of Lake Colours, Reactions of Natural Dye- stuffs, Aniline Lakes, Coal-Tar Colouring Matters, Precipi- tating Agents for Aniline Lakes, Manufacture of Aniline Lakes, Vermilionettes, and Royal Reds, Scarlet Lakes, Orange Lakes, Yellow Lakes, Blue Lakes, Brown Lakes, Violet Lakes, Black Lake, Green Lake, Alizarine Lakes, 259-293 Colour and Hue, Brilliancy or Luminosity, Colouring Power, Cover- PAINTERS' COLOURS, OILS, AND VARNISHES. CHAPTER I. INTRODUCTORY. COLOUR, COLOURS, PAINTS, AND VARNISHES. Colour is a term used by persons in several senses; hence confusion sometimes arises, although, as a rule, the context leaves no doubt as to the particular sense intended. When a beam of white light is made to pass through an angle of a triangular prism in a certain manner, and the light which has passed through is received upon a screen, we find that it has undergone a wonderful change; instead of being one uniform colour, as it was originally, it is spread out into a band of many colours, of which seven can readily be distinguished-viz., red, orange, yellow, green, blue, indigo, and violet. We see these colours by the effect or sensation produced by their action on the retina of the eye; in a sense, therefore, these colours have an abstract existence only, we can see them by the eye, but we cannot handle them as we can a piece of cotton. When we speak of a red colour or a green colour, we use the term "colour" in an abstract sense to indicate the sensation which these colours create in our eyes. On the other hand, we often speak of coloured bodies (that is bodies which give the sensation of being coloured when we look at them) as "colours," especially when (as with vermilion, chrome yellow, emerald green, Prussian blue, and magenta) they can be used to impart colour to other bodies. In this way "colour" is used in a concrete sense to indicate |