(B) Yellow Earths 23 Brown Ironstone 23 Ochre 25 Yellow Earth 26 Terra di Siena 27 (C) The Red Earths 27 Red Ironstone 28 Bole 31 Alum Sludge 32 Mine Sludge 32 (D) Blue Earths 33 Azurite, or Ultramarine 33 Vivianite 33 (E) Green Earth Pigments 34 Green Earth 34 Malachite 35 (F) Brown Earth Pigments 36 Umber 36 Asphaltum 37 (G) Black Earth 38 Black Schist 38 Graphite 38 CHAPTER III THE PREPARATION OF THE COLOUR EARTHS 40 Crushing Machinery 43 Crushing and Sifting 77 Calcining 81 Mixing and Improving 81 Moulding 85 CHAPTER IV WHITE EARTH COLOURS 87 Caustic Lime 87 Pearl White 94 Vienna White 95 Chalk 98 Precipitated Chalk 107 Calcareous Marl 110 Gypsum 111 Kaolin, Pipeclay 112 Barytes, or Heavy Spar 119 Carbonate of Magnesia 123 Talc 124 Steatite or Soapstone 125 CHAPTER V