CHAPTER XXXIX.

PRECIOUS STONES.

Diamonds—Diamond Cutting—Rose Diamonds—Brilliants—The Diamond District in Brazil—Diamond Lavras—The great Russian Diamond—The Regent—The Koh-i-Noor—Its History— The Star of the South—Diamonds used for Industrial Purposes—The Oriental Ruby and Sapphire—The Spinel—The Chrysoberyl—The Emerald—The Beryl—The Zircon—The Topaz— The Oriental Turquoise—The Garnet—Lapis Lazuli—The Noble Opal—Inferior Precious Stones—The Agate-Cutters of Oberstein—Rock Crystal—The Rock-crystal Grotto of the Galenstock 477

LIST OF ILLUSTRATIONS.

MAPS.

Of the World, showing the distribution of Volcanoes and the Districts visited by Earthquakes _to face page_ 60

Of Great Britain, showing the Coal-fields and chief Mining Districts 400

Of America, showing the Coal-fields and Mineral Districts 410

WOODCUTS.

PAGE

Carboniferous Forest _engraved by_ G. Pearson, _to face title_

Tabular Geological Profile of Strata with corresponding _engraved by_ G. Pearson Fossils 3

Aqueous Strata disturbed by Igneous Formations ” ” 4

_Ammonites Henleyi_ (Middle _from_ Haughton’s ‘Manual of Lias) Geology’ 9

Trilobite _from_ Kemp’s ‘Phasis of Matter’ 11

Magnified Eye of Trilobite ” ” 11

_Pterygotus acuminatus_ _from_ Haughton’s ‘Manual of (Eurypterid) Geology’ 12

_Spirifer princeps_ (Brachiopod) ” ” 12

_Pterichthys Milleri_, restored (Old Red Sandstone of Scotland) ” ” 14

_Ventriculites_, Fossil Sponge (Chalk) ” ” 16

_Siphonia costata_, Fossil Sponge, (Green Sand, ” ” Warminster) 16

_Encrinus liliiformis_ (Muschelkalk, Germany) ” ” 17

_Pentacrinus briareus_ ” ” 17

_Marsupites ornatus_ (Chalk) ” ” 18

_Turrilites tuberculatum_ ” ” 19

Restored Belemnite ” ” 19

_Ichthyosaurus communis_ ” ” 20

_Plesiosaurus dolichodeirus_ (British Museum—found in the _from_ Haughton’s ‘Manual of Lias of Street, near Geology’ Glastonbury) 21

_Glyptodon clavipes_ ” ” 25

Diagram illustrating action of _engraved by_ G. Pearson Syphon 44

Section of an Intermittent Spring ” ” 45

Geysirs of Iceland ” ” 46

Porous Strata, Artesian Well sunk in the London Basin ” ” 49

Middle and Valley Lake Craters, _from_ Wood’s ‘Australia’ _to face Mount Gambier, South page_ Australia 53

Extinct Crater of Haleakala _from_ Webb’s ‘Celestial Objects’ 57

Eruption of Vesuvius, Bay of _engraved by_ G. Pearson, _to face Naples page_ 81

Mud Volcanoes of Trinidad _engraved by_ G. Pearson 94

Great Earthquake at Lisbon _engraved by_ G. Pearson, _to face page_ 114

Axmouth Landslip _engraved by_ G. Pearson 128

Stalactital Cavern at Aggtelek: _engraved by_ G. Pearson, _to face the Cave of Borodla page_ 133

Entrance to the Cave of _engraved by_ G. Pearson Adelsberg 137

Stalactital Cavern in Australia _from_ Wood’s ‘Australia’ 141

Cave under Bonifacio _from_ Forester’s ‘Corsica’ 145

_Leptodirus Höchenwartii_ _engraved by_ G. Pearson 163

The _Proteus anguinus_ ” ” 165

Blind Fish (_Amblyopsis spelæus_) ” ” 168

Indian Rock-cut Temple _engraved by_ G. Pearson, _to face page_ 178

Rock Temples of Ajunta (general _engraved by_ G. Pearson view) 182

Lower Glacière of St. Livres _from_ Browne’s ‘Ice Caves’ 193

Ice Streams in the Upper Glacière of St. Livres ” ” 196

Entrance to the Glacière of St. Georges ” ” 201

Gallery with Tombs _from_ Northcote and Brownlow’s ‘Roma Sotterranea’ 206

Cave in Dream Lead Mine, near _engraved by_ G. Pearson Wirksworth, Derbyshire 216

Boring Machine in the Tunnel, _taken from the_ ‘Illustrated Mont Cenis { } London News’ _by permission_ 238

Boring Machine in the Second Working Gallery, Mont Cenis Tunnel ” ” 239

Process of Boring _engraved by_ G. Pearson 251

Section of a Lead Mine in _from_ Ure’s ‘Dictionary of Cardiganshire { Arts, } Manufacture, and Mines’. 252

Part of a Colliery laid out in four panels ” ” 255

General View of Mining _engraved_ by G. Pearson Operations 257

Tools used by Miners in _from_ Ure’s ‘Dictionary of Cornwall { Arts, } Manufactures, and Mines’ 258

Conveyance of Minerals _engraved by_ G. Pearson underground 262

Miners descending Shaft in Owen’s Safety Cage ” ” 265

Timbering of a Mine _from_ Ure’s ‘Dictionary of { Arts, } Manufactures, and Mines’ 258

Transverse Sections of Walled Drain Galleries ” ” 269

Drainage of a Mine by Adit Levels ” ” 269

Safety Lamp ” ” 280

Gold-washing in Australia _engraved by_ G. Pearson 292

Stamping Mill _from_ Ure’s ‘Dictionary of Arts, Manufactures, and Mines’ 306

Grinding Mill ” ” 307

The Botallack Mine, Cornwall _engraved by_ G. Pearson 317

St. Michael’s Mount, Cornwall ” ” 333

Blast Furnace _from_ Ure’s ‘Dictionary of Arts, Manufactures, and Mines’ 352

Pecopteris adiantoides _from_ Haughton’s ‘Manual of Geology’ 391

Sphenopteris affinis ” ” 391

Lepidodendron elegans ” ” 392

Asterophyllites comosa ” ” 392

Sigillaria oculata ” ” 392

Calamites nodosus ” ” 393

Coalbeds rendered available by _from_ ‘Our Coal and Our Coal Pits’ elevation, 397

Section of Coal-field south of { _from_ Ure’s ‘Dictionary of } Malmesbury Arts, Manufactures, and Mines’ 398

Coal-basin of Clackmannanshire ” ” 403

Dudley Coal-field _from_ Howitt’s ‘Visits to Remarkable Places’ 407

Shipping Coal ” ” 412

Coal Hewers at Work _engraved by_ G. Pearson 415

Pitch Lake of Trinidad _engraved by_ G. Pearson, _to face page_ 429

Insects and Vegetable _engraved by_ G. Pearson Substances inclosed in Amber, 452

Penrhyn Slate Quarry, North _engraved by_ G. Pearson, _to face Wales page_ 469

The following is a list of the full-page illustrations, included in the foregoing list, all of which, except No. 2, are engraved by G. Pearson:—

1. Carboniferous Forest _to face title_

2. Middle and Valley Lake Craters, Mount Gambier, South Australia _to face page_ 53

3. Eruption of Vesuvius, Bay of Naples ” 81

4. Great Earthquake at Lisbon ” 114

5. Stalactital Cavern at Aggtelek; the Cave of Borodla ” 133

6. Indian Rock-cut Temple: Porch of the Chaitya Cave Temple, Ajunta ” 178

7. Pitch Lake of Trinidad ” 429

8. Penrhyn Slate Quarry, North Wales ” 469