Chapter II: The Raw Materials for Earth Colours 8

(A) White Raw Materials and Pigmentary Earths 11

Limestone (Calcite, Limestone, Chalk) 11

Gypsum (Alabaster) 18

Barytes, or Heavy Spar 19

Talc, Soapstone, Steatite 20

Clay 21

(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

YELLOW EARTH COLOURS 127
The Ochres 128
Calcining (Burning) Ochre 132
Ochres from Various Deposits 136
Artificial Ochres 138
Ochres as By-products 146

CHAPTER VI

RED EARTH COLOURS 151
Bole 152
Native Ferric Oxide as a Pigment 154
Iron Glance 154
Hematite 155
Raddle 155
Burnt Ferric Oxide and Ochres 158
(_a_) Burning in the Muffle 158
(_b_) Caput Mortuum, Colcothar 160
(_c_) Calcining Ferric Oxide 161
Ferric Oxide Pigments from Alum Sludge 164

CHAPTER VII

BROWN EARTH COLOURS 168
Terra di Siena 168
True Umber 170
Cologne Earth (Cologne Umber) 173
Asphaltum Brown (Bitumen) 174

CHAPTER VIII

GREEN EARTH COLOURS 176
Green Earth, or Celadon Green 176
Artificial Green Earth (Green Ochre) 180
Malachite Green 181

CHAPTER IX

BLUE EARTH COLOURS 183
Malachite Blue (Lazulite) 183
Vivianite or Blue Ochre 184

CHAPTER X

BLACK EARTH COLOURS 185
Graphite 185
Black Chalk 194

CHAPTER XI

THE COMMERCIAL NOMENCLATURE OF THE EARTH COLOURS 197
White Earth Colours 198
Yellow Earth Colours 200
Red Earth Colours 200
Brown Earth Colours 200
Green Earth Colours 201
Blue Earth Colours 202
Grey Earth Colours 202
Black Earth Colours 202

INDEX 203

EARTH COLOURS