Brushes 355 Water-colours 356 Removing odour 356 Discoloration 356 Composition 358 Area covered 360 Measuring 360 Carriage and Car painting 361 Woodwork painting 368 Iron painting 369 Fresco painting 378 INDEX 383 ILLUSTRATIONS. FIGURE PAGE 1, 2. BONE-BLACK FURNACE 8 3-11. APPARATUS FOR MAKING LAMP-BLACK 12-22 12. FURNACE FOR ROASTING COBALT ORES 31 13. FURNACE FOR MAKING SMALTS 33 14-17. YELLOW PRUSSIATE FURNACE 60 18-20. HANNAY’S WHITE LEAD FURNACE 217 21-25. LEWIS’S WHITE LEAD FURNACE 226, 230 26, 27. MACIVOR’S WHITE LEAD PROCESS 233, 239 28. APPARATUS FOR MAKING ZINC OXIDE 248 29. APPARATUS FOR MAKING ZINC SULPHIDE 253 30-32. FURNACE FOR ROASTING OCHRES 278 33-39. APPARATUS FOR EXTRACTING SEED-OILS 309-315 40-44. WRIGHT & CO.’S PAINT MILLS 340-344 45. HIND & LUND’S PAINT MILL 346 46-48. BRINJES AND GOODWIN’S PAINT MILLS 347, 348 49. NOAKES & CO.’S METALLIC KEG 350 CHAPTER I. PRELIMINARY. =Colour.=--The term “colour” is inappropriately given by common usage to material substances which convey a sense of colour to the human eye, but is properly restricted to that sense itself. The material colour should be called “pigment” or “dyestuff” in the raw state, and paint when compounded with other substances for application in the form of a coating. The sense of colour is due to light. In the absence of light there is no colour, only blackness; and black is really no colour, but an absence of colour. Very many conditions combine to cause different colour sensations, some of which are understood, while others we are not able to explain.