CORNELL UNIVERSITY LIBRARY GIFT OF Roger P. Clark Cornell University Library The original of tliis book is in tlie Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003971755 THE SUBTERRANEAN WORLD. LONDON : PRINTED BY SPCCTISWOODE AND CO.^. 3SBW-STnEET SQUARE AND PARLIAMfeN,T STREET THE SUBTERRANEAN WORLD. DE. GEOEGE HAETWIG, ATITHOE OF * THE SEA AND ITS UVING WONDERS," * THE TROPICAL WOKLD,' • THE POLAR WORLD,' AND *THB HARMONIES OF NATURE," WITH THREE MAPS AND NUMEROUS ENOSAVINOS ON WOOD. LONDON : LONGMANS, GEEEN, AND CO. 1871. PREFACE NATURE displays her wonders not only in the starry heavens or in the boundless variety of animal and vegetable life on the surface of our earth. In the dark regions underground she likewise shows us much that is remarkable or beautiful, or carries on gigantic operations, which are sometimes beneficent and sometimes disastrous to mankind. There lie concealed the mysterious laboratories of fire, which reveal to us their existence in earthquakes and volcanic explosions. There, in successive strata, repose the remains of extinct animals and plants. There many a wonderful cavern may be seen, with its fantastic stalactites, its rushing waters, and its noble halls. There have been deposited the rich stores of mineral wealth— the metals, the coals, the salt, the sulphur, &c. — without whose aid man would never have been more than a savage. The aim of the present work has been to describe the wonders of this hidden world in their various relations VI PEEFACE. to man, now raising him to wealth, and now dooming him to destruction. The author trusts that he may have succeeded in giving a sketch of the phenomena resulting from the action of subterranean forces, which, with his account of the wonders of the sea, of the tropics, and of the frozen regions, may impart to the reader a fair idea of the history and present condition of the wonderful world in which we live. Salon, near Ltjdwi&sbtjkg : July 6, 1871. CONTENTS CHAPTER I. GEOLOGICAL EETOLUTIONS. The Eternal Strife between Water and Fire — Strata of Aqueous Origin — Tabular View of their Chronological Succession — Enormous Time required for their Formation — Igneous Action — Metamorphie Rocks — Upheaval and Depression — Fossils — Uninterrupted Succession of Organic Life .... Page 1 CHAPTER II. FOSSILS. General Remarks — 'Eozoon Canadense — Trilobites — Brachiopods — Pterichthys MiUeri — Oldest Reptiles — Wonderful Preservation of Colour in Petrified Shells — Primaeval Corals and Sponges — Sea-lilies — Orthoeeratites and Ammonites — Beleranites — Ichthyosaurus and Plesiosaurus -^ Pterodactyli — ■ Iguanodon — Tertiary Quadrupeds — ■ Dinotherium — Colossochelys Atlas — Megatherium — Mylodon — Glyptodon — Mammoth — Mastodon — Sivatherium G-iganteum — Fossil Ripple-marks, Rain^drops, and Footprints — Harmony has reigned from-the beginning . 8 CHAPTER III. StjBTEfiRANEAl* HEAT, Zone of invariable Temperature — Increasing Temperature lit the Earth at a greater Depth — Proofs found in Mines and Artesian Wells, in Hot Springs and Volcanic Eruption S^The whole Earth probably at one time a fluid mass 31 CHAPTER IV. SOBTEERANEAN CMEAVALS AliD DEGRESSIONS. Oscillations of the Earth's Surface taking place in the present day — First ascertained in Sweden — Examples of Contemporaneous Upheaval and Depression in France and England — Probable Oiuses of the Phenomenon . , .34 vm CONTENTS. CHAPTER V. SUBTERRANEAN WATERS AND ARTESIAN WELLS. Subterranean Distribution of the Waters— Admirable Provisions of Nature- Hydrostatic Laws regulating the Plow of Springs— Thermal Springs— Inter- mittent Springs — The Geysir— Bunsen's Theory— Artesian Wells — Le Puits de Grenelle— Deep Borings— Various Uses of Artesian Wells— Artesian Wells in Venice and in the Desert of Sahara Page 39 CHAPTER VI. VOLCANOES. Volcanic Mountains — Extinct and active Craters — Their Size — Dangerous Crater- explorations — Dr. Judd in the Kilauea Pit — Extiuct Craters — Their Beauty — The Crater of Mount Vultur in Apulia — Volcanoes still constantly forming — JoruUo and Isaleo — Submarine Volcanoes — Sabrina and Graham's Island — Santorin — Number of Volcanoes — Their Distribution — Volcanoes in a constant state of eruption— Stromboli — Fumaroles — The Lava-lakes of Kilauea — Volcanic Paroxysms — Column of Smoke and Ashes — Detonations — Explosion of Cones — Disastrous Effects of Showers of Ashes and Lapilli— Mud Streams — Fish disgorged from Volcanic Caverns — Eruptions of Lava — Parasitic Cones — Phenomena attending the Flow of a Lava Stream — Baron Papalardo — Meeting of Lava and Water — Scoriae — Lava and Ice — Vast Dimensions of several Lava Streams — Scenes of Desolation — Volcanoes considered as Safety-valves — Probable Causes of Volcanoes ...... . .53 CHAPTER VII. DESTRUCTION OF HERCULANEDM AND POMPEII. State of Vesuvius before the eruption in the year 79 A.c— Spartacus — Premonitory Earthquakes — Letter of Pliny the Younger to Tacitus, relating the death of his uncle, Pliny the Elder — Benevolence- of the Emperor Titus — Herculaneum and Pompeii buried under a muddy alluvium — Herculaneum first discovered in 1713 ... . . . .... 81 CHAPTER VIII. GAS SPRINGS AND MUD VOLCANOES. Carbonic-acid Springs — Grotto del Cane— The Valley of Death in Java Exagge- rated Descriptions— Carburetted Hydrogen Springs — The Holy Fires of Baku — Description of the Temple— Mud Volcanoes — The Maealuba iu Sicily— Crimean Mud Volcanoes — Volcanic Origin of Mud Volcanoes ■ • . . 88 CONTENTS. IX CHAPTER IX. EARTHQUAKES. Extent of Misery inflicted by great Earthquakes — Earthquake Regions — Earth- quakes in England — Grreat Number of Earthquakes — Vertical and Undulatory Shocks— ^Warnings of Earthquakes — Sounds attending Earthquakes — Remark- able Displacements of Objects — Extent and J?orc6 of Seismic "Wave Motion — Effects of Earthquakes on the Sea — Enormous Waves on Coasts — Oscillations of the Ocean— Fissures, Landslips, and shattering Falls of Rock caused by Earth- quakes —Causes of Earthquakes — Probable Depth of Focus — Opinions of Sir Charles Lyell and Mr. Poulett Sorope— Impressions produced on Man and Animals by Earthquakes . . . . Page 97 CHAPTER X. THE GEEAT EARTHQUAKE OF LISBON. A dreadful All Saints' Day — The Victims of a Minute — Report of an Eye-witness — Conflagration — Banditti — Pombal brings Chaos into Order — Intrigues of the Jesuits — Damages caused by the Earthquake in other places ; at Cadiz ; in Barbary — Widespread Alarm — Remarks of Goethe on the Earthquake . 114 CHAPTER XI. LANDSLIPS. Igneous and Aqueous Causes of Landslips — Fall of the Diablerets in 1714 and 1749 — Escape of a Peasant from his living Tomb — Vitaliano Donati on the Fall of a Mountain near Sallenches — The Destruction of Goldau in 1806 — Wonderful Preservation of a Child — Burial of Velleja and Tauretunum, of Pliirs and Scilano — Landslip near Axmouth in Dorsetshire — Falling in of Cavern-roofs — DoUinas and Jamas in Carniola and Dalmatia — Bursting of Bogs — Crateriform Hollows in the Eifel 121 CHAPTER XII. ON CAVES IN GENERAL. Their various Forms — Natural Tunnels— The Ventanillas of Gualgayoc — Eimeo — Torgatten — ^Hole in the Miirtschenstook — The Trebich Cave — Grotto of Anti- paros — Vast Dimensions of the Cave of Adelsberg and of the Mammoth Cave — Discovery of Baumanu's Cave — Limestone Caves- Causes of their Excavation— Stalactites and Stalagmites — Their Origin — Variety of Forms — ■ Marine Caves — Shetland — Fingal's Cave — The Azure Cave — Cave under Bonifacio — Grotta di Nettuno, near Syracuse — The Bufador of Papa Luna — Volcanic Caves — The Fossa delta Palomba — Caves of San Miguel — The Surtshellir 133 X CONTBJ^TS. CHAPTEE XIII. CAVE EIVBES. The Fountain of Vaucluse— TheFontaine-sans-fond— The Katabothra in Morea — Subterranean Rivers in Carniola — Subterranean Navigation of the Poik in the CaveofPlanina— 'The Stalactital Paradise '—The Piuka Jama . Page 149 CHAPTER XIV. SUBTBKEANEAN LIFE. Subterranean Vegetation — ^Fungi — Enormous Fungus in a Tunnel near Doncaster — Artificial Mushroom-beds near Paris — Subterranean Animals — The Guacharo — ^Wholesale Slaughter — Insects in the Cave of Adelsberg — The Leptodirus and the Blothrus — The Stalita tsenaria — The 01m or Proteus — The Lake of Cirk- nitz — The Archduke Ferdinand and Charon — The Blind Rat and the Blind Fish of the Mammoth Cave 156 CHAPTEE XV. CAVES AS PLACES OF EEFUGE. The Cave of Adullam — Mahomet in the Cave of Thaur — The Cave of Longara — The Cave of Egg— The Caves of Eathlin— The Cave of Yeermalik— The Caves of Grenada — Aben Aboo, the Morisco King — The Caves of Gortyna and Melidoni — Atrocities of French Warfare in Algeria — The Caves of the Dahra — The Cave ofShelas — St. Arnaud 169 CHAPTEE XVI. HEEMIT CAVES — ROCK TEMPLES — BOCK CHtJRCBES. St. Paul of Thebes — St. Anthony — His visit to Alexandria, and death — Numerous Cave Hermits in the East — St. Benedict in the Cave of Subiaoo— St. Cuthbert^ St. Beatus — Eook Temples of Kanara — The Wonders of EUora Ipsamboul ■ Rock Churches of Lalibala in Abyssinia — The Cave of Trophonios-^The Grotto of St. Rosolia near Palermo — The Chapel of Agios Niketas in Greece— The Chapel of Oberstein on the Nahe— The repentant fratricide , . ,178 CHAPTEE XVII. ICE CAVES AND WWD-HOLES. Ice-caves'of St. Georges acd St. Livres— Beautiful Ice-stalagmites in the Cave of La Baume-^The Schafloch— Ice Cataract in the tipper Glaciire of St Livres — Ice Cavern of Elsener^— The Care of Yeermalik — Volcanic Ice-caves JEolian Caverns of Terni— Causes of the low temperature of Ice-eavcs . 1 99 CONTENTS. XI CHAPTER XVIII. EOCK TOMBS AND CATACOMBS. Biban-el-Molulc, the Eoyal Tombs of Thebes — The Roman Catacombs — Their Extent — Their Mode of Excavation — Touching Sepulchral Inscriptions— Antony Bosio, the Columbus of the Catacombs — The Cavaliere di Rossi — Tlie Catacombs of Naples and Syracuse — The Catacombs of Paris .... Page 202 CHAPTER XIX. CAVES CONTAINING REMAINS OF EXTINCT ANIMALS. The Cave Hyena and the Cave Bear— The Cavern of Kirkdale — The Moa Caves in New Zealand — Various Species of Moas — Their enormous size . ,213 CHAPTER XX. SUBTEKEANEAN EBLICS OF PEEHISTOEIC MAN. The Peat Mosses of Denmark — Shell-Mounds — Swiss Lacustrine Dwellings — An- cient Mounds in the Valley of the Mississippi — The Caves in the Valley of the Meuse — Dr. Schmerling — Human Skulls in the Cave of Engis — Explorations of Sir Charles Lyell in the Cave of Engihoul — Caverns of Brixham — Caves of Gower — The Sepulchral Grotto of Aurignac — Elint Implements discovered in the Valley of the Somme — Gray's Inn Lane an ancient Hunting-Ground for Mammoths 221 CHAPTER XXI. TEOGLODYTES OE CAVE-DWELLEES. CANNIBAL CAVES. Cave Dwellings in the Val d'Ispica — The Sicanians — Cannibal Caves in South Africa — The Rock City of the Themud — Legendary Tale of its Destruction , 232 CHAPTER XXII. TUNNELS. Subterranean London — The Mont Cenis Tunnel — Its Length — Ingenious Boring Apparatua^The Grotto of the Pausilippo — The Tomb of Virgil . . 237 CHAPTER XXIIL ON MINES IN GENEEAL, Perils of the Miner's Life — Number of Casualties in British and Foreign Coal Mines — Life in » Mine — Occurrence of Ores — Extent and Depth of Metallic Veins — Mines frequently discovered by Chance — The Divining Rod — Experi- XU CONTENTS. mental Borings — Stirring Emotions during their Progress — Sinking of Shafts Precautious against Influx of Water— Expense— Shaft Accidents — Various Methods of working Mineral Substances— "Working in Direct and Eererse Steps- Working hy Transverse Attacks— Open Quarry Workings— Pillar and Stall Sys- tem—Long Wall System— Dangerous Extraction of Pillars— Mining Implements —Blasting— Heroes in Humble Life— Firing in the Mine of Eammelsberg— Transport of Minerals Underground— Modern Improvements — Various Modes of Descent— Corfs— Wonderful Preservation of a Girl at Fahlun— The Loop- Safety Cage— Man Machines— Timbering and Walling of Galleries— Drainage by Adit Levels— Eemarkable Adits — The Great Cornish Adit — The Georg Stollen in the Hartz — The Ernst August Stollen— Steam Pumps — Drowning of Mines — Irruption of the Sea into Workington Colliery — Hubert Goffin — Irruption of the Eiver Garnock into a Mine — Ventilation of Mines — Upcast Shafts — Eire Damp — Dreadful Explosions — The Safety Lamp — The Choke Damp — Conflagrations of Mines— The Burning Hill in Staifordslure . . Page 244 CHAPTEE XXIV. GOLD, The Golden Fleece — Golden Statues in ancient Temples — A Free-thinking Soldier — Treasures of ancient Monareha — First Gold Coins — Ophir — Spanish Gold Mines — Bohemian Gold Mines — Discovery of America — Siberian Gold Mines — California — Marshall — Eush to the Placers — Discovery of Gold in Australia — The Chinaman's Hole — New El Dorados — Alluvial Gold Deposits in California and Australia — Washing— Quartz-crushing .... 285 CHAPTEE XXV. SILVER. Its ancient Discovery — Its Uses among the luxurious Eomans —The Mines of Laurium — Silver Mines of Bohemia, Saxony, and Hungary — Colossal Nuggets — Silver Ores — Silver Production of Europe — Mexican Silver Mines — The Veta Madre of Guanaxuato — The Conde de la Valenciana — Zacatecas and Catorce^ Adventures of a Steam Engine— La Bolsa de Dios Padre — The Conde dela Eegla — Ill-fated English Companies — Indian Carriers — The Dressing of Silver Ores — Amalgamating Process — Enormous Production of Mexican Mines — Potosi — Cerro de Pasco— Gualgayoc— The Mine of Salcedo— Hostility of the Indians — The Monk's Eosary — Chilian Mines — The Comstock Lode . . . 29? CHAPTEE XXVI. COPPER. Its valuable Qualities — English Copper Mines— Their comparalively recent Importance — Dreary Aspect of the Cornwall Copper Country — Botallack Sub- marine Copper Mines — A Blind Miner — Swansea — Smelting Process The Mines of Fahlun— their Ancient Records— Alten Fjord— Drontheim The Mines of Eoraas — The Mines of Mansfeldt — Lake Superior — Mysterious Discoveries — Burra Burra- Eemarkable Instances of Good Fortune in Copper MiniuK 31 ft CONTENTS. Xlll CHAPTER XXVII. TIN. Tin known from the most remote antiquity — Phoenician Traders — Tlie Cassiterides - Diodorus Sicuhis — His aeconnt of the Cornish Tin Trade — The Age of Bronze — Valuable Qualities of Tin — Tin Countries — Cornish Tin Lodes — Tin Streams — Wheal Vor — A Subterranean Blacksmith — Huel Wherry, a Tin Mine under the Sea— Carclaze Tin Mine — Dressing of Tin Ores — Smelting —The Cornish Miner .... . . Page 332 CHAPTER XXVin. IRON. Iron the most valuable of Metala — Its wide Diffusion over the Earth — Meteoric Iron — Iron very anciently known — Extension of its Uses in Modern Times — British Iron Production — Causes of its Rise — Hot Blast — Puddling — Coal Smelt- ing — The Cleveland District — Rapid Rise of Middlesborough — British Iron Ores — Production of Foreign Countries — The Magnetic Mountain in Russia — The -Eisenerz Mountain in Styria — Dannemora — Elba — The United States — The Pilot Knob— The Cerro del Mercado 345 CHAPTER XXIX. LEAD. Its Properties and extensive Uses — Alston Moor — Belgian Lead Mines — Galena in America — Extraction of Silver from Lead Ores — Pattinson'e Process — A great part of our wealth is due to the laboratory . . . . . 364 CHAPTER XXX. MEECUET. Not considered as a true Metal by the Ancients — Its Properties and Uses — Almaden — Formerly worked by Convicts — Diseases of the Miners — Idria — Its Discovery — Conflagration of the Mine— Its Produce — Huancaveliea— New Almaden 370 CHAPTER XXXI. THE NEW METALS. Zinc — The Ores, but not the Metal, known to the Ancients — Rapid increase of its Production — Chief Zinc-producing Countries -Platinum — Antimony — Bismuth —Cobalt and Nickel— Wolfram— Arsenic— Chrome— Manganese— Cadmium- Titanium — Molybdenum — Aluminium — Aluminium Bronze — Magnesium — Sodium— Palladium— Rhodium— Thallium 380 XIV CONTENTS. CHAi'TER XXXII. COAL. The Age of Coal— Plants of the Carboniferous Age— Hugh Miller's Description of a Coal Forest — Vast Time required for the Formation of the Coal-fields — Derange- ments and Dislocations— Faults — Their Disadvantages and Advantages— Bitu- minous Coals — Anthracites — Our Black Diamonds — Advantageous Position of our Coal-Mines. — The South Welsh Coal-field — Great Central and Manchester Coal-fields — The Whitehaven Basin and the Dudley Area — Newcastle and Dur- ham Coal-fields — Costly Winnings — A Ball in a Coal-pit— Submarine Coal Mines • — Newcastle— View from Tynemouth Priory — Hewers — Cutting Machines — Putters — Onsetters — Shifters — Trapper-boys — George Stephenson — Eise of Coal Production — Probable Duration of our Supply — Prussian Coal Mines — Belgian Coal Mines — Coal Mines in various other countries — Maunch Chunck . Page 390 CHAPTER XXXIII. BITUMINOUS SUBSTANCES. Formation of Petroleum — Enormous Production of the Pennsylvanian Wells — Asphalte used by the Ancients — Asphalte Pavements — The Pitch Lake of Trinidad— Jet— Its Manufacture in Whitby 426 CHAPTER XXXIV. SALT. Geological Position of Rock Salt — Mines of Nprthwich — Their immense Excava- tions — Droitwich and Stoke — Wieliczka — Berchtesgaden and Reichenhall — Admirable Machinery — Stassfurt — Processes employed in the Manufacture of Salt — Origin of Rock-salt Deposits 431 CHAPTER XXXV. SULPHUE. Sulphur Mines of Sicily — Conflagration of a Sulphur Mine — The Solfataras of Krisuvick — Iwogasima in Japan — Solfatara of Puzzuoli — Crater of TeneriflFe — Alaghez — Biidosbegy in Transylvania — Sulphur from the Throat of Popocatepetl — Sulphurous Springs — Pyrites — Mines of San Domingo in Portugal — The Baron of Pommorao . . . . . . . ,441 CHAPTER XXXVI. AMBEE. Various Modes of its Collection on the Prussian Coast — What is Amber? The extinct Amber Tree — Insects of the Miocene Period inclosed in Amber Formidable Spiders — Ancient and Modern Trade in Amber . ^ _ 449 CONTENTS. XV CHAPTER XXXVII. MISCELLANEOUS MINERAL SUBSTANCES USED IN THE IKDUSTKIAL AETS. Alum — Alum Mines of Tolfa — Borax — The Suffioni in the Florentine Lagoons — China-clay — How formed? — Its Manufacture in Cornwall — Plumbago — Emery — Tripolite Page 458 CHAPTER XXXVIII. CELEBRATED QUARRIES. Carrara — The Pentelikon — The Parian Quarries — Rosso antico and Verde antico — - The Porphyry of Elfdal— The Gypsum of Montmartre— The Alabaster of Vol- terra — The Slate Quarries of Wales — 'Princesses' and 'Duchesses' — ' Ladies' and ' Fat Ladies' — St. Peter's Mount near Maestricht — Egyptian Quarries — Haggar Silsilis — The Latomise of Syracuse — A Triumph of Poetry . . ,464 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 pays 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 Porest . . . engraved by G. Pearson, to face title Tabular Geological Profile of Strata with correspond- ing Fossils ..... engraved by G. Pearson 3 Aqueous Strata disturbed by Igneous Formations . „ „ 4 AmmoniUs Henleyi [UliAAi.'e Jjzs) /rom Haughton's 'Manual of Geology' 9 Trilobite .... from Kemp's ' Phasis of Matter ' 1 1 Magnified Eye of Trilobite . . „ „ „ 11 Pterygotus acuminatus (Eurypterid)/ro»i Haughton's 'Manual of Geology' 12 Spirifer princeps (Brachiopod) . „ ,, „ 12 Pterichthys Milleri, restored (Old Red Sandstone of Scotland) ...... „ 14 Ventricidites, Fossil Sponge (Chalk) . . . „ „ 16 Siphonia costata. Fossil Sponge, Green Sand, War- minster) ......,, „ 16 Encrinus liliiformis (Muschelkalk, Germany) , „ „ 17 Pentacrinus briareus ...... ,,17 Marsupites ornatus {ChaXk) . . . . „ „ 18 TiirrilUes tuberculatus . . , . „ ,, 19 Restored Belemnite . . . . . ,, „ 19 : communis . . . . „ „ 20 XVIU LIST OF ILLUSTBATIONS. Flesiosaurus dolichodeirus (British Museum — found in the Lias of Street, near G-lastonhury)/ro>n Haughton's ' Manual of Geology ' GlyftoAon clavipes . . . „ >, >' Diagram illustrating action of Syphon . _ engraved hy G. Pearson Section of an Intermittent Spring . . • >> >> Geysirs of Iceland ......> » Porous Strata, Artesian Well sunk in the London Basin ....... >> Middle and Valley Lake Craters, Mount Gambier, South Australia from Wood's 'Australia' to face 'gage Extinct Crater of Haleakala . . from Webb's ' Celestial Objects ' Eruption of Vesuvius, Bay of Naples . engraved hy G. Pearson, to face page Mud Volcanoes of Trinidad . . . engraved by G. Pearson Great Earthquake at Lisbon . . engraved by G. Pearson, to face page Axmouth Landslip .... engraved by G. Pearson Stalactital Cavern at Aggtelek: the Cave of Borodla . . . engraved by G. Pearson, to face page Entrance to the Cave of Adelsberg . . engraved by G. Pearson Stalactital Cavern in Australia . . /rem Wood's ' Aiistralia ' Cave under Bonifacio .... from Forester's ' Corsica ' Leptodirus Hochenwartii , . . engraved by G. Pearson The Proteus anguinus . . . . „ „ Blind Fish {Amblyopsis spelceus) . . . „ „ Indian Eock-cut Temple . . engraved by Gr. 'Bea.ison, to face page Book Temples of Ajunta (general view) . engraved by G. Pearson Lower Glacifere of St. Livres . . from Browne's ' Ice Caves ' Ice Streams in the Upper GlaciJre of St. Livres „ „ Entrance to the Glacifere of St. Georges . „ „ Gallery with Tombs from Northcote and Brownlow's ' Eoma Sotterranea ' Cave in Dream Lead Mine, near Wirksworth, Derby- shire ..... engraved by G. Pearson Boring Machine in the Tunnel, Mont Cenis \ ^^^'" ^""^ **' ' ^'^st'^^ted » ( London News ' by permission > Boring Machine in the Second Working Gallery, Mont Cenis Tunnel . ,, „ Process of Boring .... engraved by G. Pearson Section of a Lead Mine in Cardiganshire 5 ■^'^'"^ ^"^'^ ' Dictionary of Arts, ) ( Manufactures, and Mines ' . ) Part of a Colliery laid out in four panels . „ General View of Mining Operations . . engraved by G. Pearson Tools used by Miners in CornwaU . \ -^^"^ '^^'^ ' Dictionary of Arts } i Manufactures, and Mines ' , ) Conveyance of Minerals underground . engraved by G. Pearson Miners descending Shaft in Owen's Safety Cage Timbering of a Mine . . . /'"'"" ^^^'^ ' Dictionary of Arts, ) ( Manufactures, and Mines ' . ) Transverse Sections of Walled Drain Galleries „ Drainage of a Mine by Adit Levels . . „ Safety Lamp .....,, Gold-washing in Australia . . . engraved by G. Pearson Stamping Mill from Tire's ' Dictionary of Arts, Manufactures, and Mines ' Grinding Mill „ „ LIST OF ILLUSTRATIONS. XIX The Botallack Mine, Cornwall , . engraved by G. Pearson St. Michael's Mount, Cornwall . . . ^> <> Blast Furnace from Ure's ' Dictionary of Arts, Manufactures, and Mines ' Pecopteris adiantoides . . from Haughton's ' Manual of Geology ' SfMnopteris qffinis Lepidodendron elegans Asterophyllites comnsa Sigillaria oculata Catamites nodosus Coalbeds rendered available hy elevation, from Our Coal and Our Coal Pits ' PAGE 317 333 3S2 391 391 392 392 392 393 397 Section of Coal-fieldsouthofMalmesbury|>™ Ure's ' Dictionary of Arts,! 393 L Manufactures, and Mines . J Coal-basin of Clackmannanshire . ,, ,, 403 Dudley Coal-field . . from Hewitt's ' Visits to Eemarkable Places ' 407 Shipping Coal . . „ ,, „ 412 Coal Hewers at Work . engraved by Gr.'P&wsion 415 Pitch Lake of Trinidad . . engraved by G. Tearson, to face page 429 Insects and Vegetable Substances inclosed in Amber, engraved tyy G. Pearson 452 Penrhyn Slate Quarry, North Wales . engraved by G. Pearson, to face 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 Gambler, South Australia .... to face page 6Z 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 CHAPTER I. GEOLOGICAL BETOLUTIONS. The Eternal Strife between Water and Pire — Strata of Aqueous Origin — Tabular View of their Chronological Succession — ^Enormous Time required for their Formation — Igneous Action — Metamorphic Rocks — Upheaval and Depression — ■ Fossils — Uninterrupted Succession of Organic Life. GEOLOGY teactes us tliat, from times of the remoteness of wMch the human mind can form no conception, the surface of the earth has been the scene of perpetual change, resulting from the action and counter-action of two mighty agents — water and subterranean heat. Ever since the first separation between the dry land and the sea took place, the breakers of a turbulent ocean, the tides and currents, the torrents and rivers, the expansive power of ice, which is able to split the hardest rock, and the grinding force of the glacier, have been constantly wearing away the coasts and the mountains, and transporting the spoils of continents and islands from a higher to a lower level. During our short historical period of three or four thou- sand years, the waters, in spite of their restless activity and the considerable local changes effected by their means, have indeed produced no marked alteration in the great outlines of the sea and land ; but when we consider that their in- fluence has extended over countless ages, we can no longer wonder at the enormous thickness of the stratified rocks of aqueous origin which, superposed one above the other in successive layers, constitute by far the greater part of the earth-rind. Our knowledge of these sedimentary formations is indeed as yet but incomplete, for large portions of the surface of the globe have never yet been scientifically explored ; but a 3. Silurian 4. Devonian 2 THE SUBTERRANEAN WORLD. careful examination and comparison of the various strata composing the rocky foundations of numerous countries, have already enabled the geologist to classify them iuto the following chronological systems or groups, arranged in an ascending series, or beginning with the oldest. 1. Laurentian, named from its discovery northward of the River St. Lawrence in Canada. on \. ■ -) These three groups owe their name to their ^. OamDrian ' . ___ , ~ — ^ , , occurrence m Wales and Devonshire, where they were first scientifically ex- plored. 5. Carboniferous. In this group the most important coal- fields are found. 6. Permian, from the Russian province of Permia. 7. Triassic. 8. Lias. 9. Oolite. 10. Cretaceous. 11. Tertiary : subdivided into Eocene, Miocene, and Plio- cene. 12. Recent marine and lacustrine strata. Each of these systems consists again of numerous sections and alternate layers, sometimes of marine, sometimes of freshwater formation, the mere naming of which would fill several pages. When we reflect that the Laurentian system alone has a thickness of 30,000 feet ; that many of the numerous sub- divisions of the Tria.ssic or Oolitic group are 600, 800, or even several thousand feet thick, and that each of these enormous sedimentary formations owes its existence to the disintegration of pre-existing mountain masses — we can form at least a faint notion of the enormous time which the whole system required for its completion. Had the levelling power of water never met with an antago- nistic force, there can be no doubt that the last remains of the dry land, supposing it could ever have risen above the ocean, must long since have been swept into the sea. But while water has been constantly tending to reduce the irregularities of the earth's surface to one dull level, the expansive force of subterranean heat has been no less unceasingly active in TABULAR GEOLOGICAL PROFILE. H EH 1. Recent Deposits 11. Devonian 12. SZLTTRIAN 13. Cambrian 14, Laubentian CHABACTERISTIC FOSSIL BEMAINS- 1. Recent Deposits, 6. Oolite. (1) Pholadomya. (2) Trigonia. (3) Mantellia. (4) Nerincea. (1) Ldbyrinlhodon. (2) Encrinus. L PERSnAN. (1) Bakewellia. (2) Productus. (3) Palceoniscus. 10. Caeeonifehous. (1) Goniatites. (2) Lepidodendi'on. (3) Catamites, 11. Devonian. Pterichthys. (1) Strophomena. (2) Lingula. (3) Pentanierus. (4) Calymene. 13. Cambrian. Oldhamia. 14. Laubentjajm". 4 THE SUBTERRANEAN WORLD. restoring the unevenness of the external crust by the ejection or protrusion of new masses of stone (porphyry, trachyte, basalt, lava, &c.), and by the consequent disturbance, in a variety of ways, of the stratified rocks. Plutonic and volcanic eruptions and upheavings, in then- reaction against the levelling tendencies of water, have in many places deranged, broken, fractured, contorted, or raised strata deposited in horizontal layers at the bottom of A AQUEOUS STRATA DISTURBED BY IGNEOUS FORMATIONS. BCD, aqueous strata, originally horizontal, raised by protrusion of A, granitic rock. the sea, or of large inland lakes. Sometimes a huge mass of crystalline rock, glowing from the furnaces of the deep, has, by its irresistible expansion, slowly forced its way through the superincumbent sedimentary formations, which, yielding to the pressure from below, now form vast miountain slopes, or vertical rock walls, or have even been so totally inverted that strata of a more ancient formation now overlie those of more modern date, and excite the wonder of the puzzled geologist. Sometimes, also, volcanic eruptions, repeated through a long lapse of ages and constantly accumulating lavas and cinders, have at length piled up large islands, such as Ice- land or Madeira, which now raise their summits thousands of feet above the ocean. But subterranean fire, and its assistant, steam, have not only produced vast mechanical changes ; they have also been the frequent causes of great chymieal metamorphoses in the rocks subjected to their action. To the calcining, decomposing and vapour-generating effects of heat, we trace the origin of the marble of Carrara, of alabaster, of gypsum, and all those PERIODS OF GEOLOGICAL FORMATIONS. 5 various species of stone whicli geologists include under the name of metamorpliic rocks. Besides the more paroxysmal and violent revolutions resulting from the action of subterranean fire, we find that the earth-rind has at all times been subject to slow oscillatory movements of upheaval and subsidence, frequently alternating on the same spot with long periods of rest. The greater part of the actual dry land has been deep sea, and then again land and ocean many times in succession ; and doubtless the actual sea bottom would exhibit similar alternations were we able to explore it. The same materials have repeatedly been ex- posed to all these changes — now raised or poured out by subterrannean fii-es, and then again swept away by the waters ; now changed from solid rock into sand and mud, and then again converted, by pressure or heat, into solid rock. Thus the history of the earth-rind opens to us a vista into time no less grand and magnificent than the vista into space afforded by the contemplation of the starry heavens. The oldest and the newest stratified rocks are coinposed of the same mineral substances; for clay, sandstone, and limestone occur in the Silurian and in the Carboniferous formation ; in the Cretaceous and Triassic systems ; in the Tertiary and in the Alluvial deposits, which have imme- diately preceded the present epoch. Where then, it may be asked, does the geologist . find a chronological guide to lead him through the vast series of strata which, in the course of countless ages, have been deposited in the water ? How is he able to distinguish the boundaries of the various periods of creation ? Where are the precise indications which enable him to decipher the enigmas which the endless feuds of fire and water have written in the annals of our globe ? The. fossil remains of animals and plants wonderfully furnish the guidance which he needs. The corals and shells, the ferns and conifera, the teeth and bones found in the various strata of the earth-rind are the landmarks which point out to him his way through the labyrinth of the primi- tive ao-es of our globe, as the compass directs the mariner over the pathless sea. Every leading fossil has its fixed chronological character, and thus the age of the formation 6 THE SUBTEEEANEAN WOELD. in which it occurs may be ascertained, and its place deter- mined in the geological scale. It would, however, be erro- neous to suppose that each successive formation has been the seat of a totally distinct creation, and that the organic remains found in one particular stratum are separated by an impassable barrier from those which characterise the pre- ceding or following sedimentary deposits. As on the surface of the earth or along the shores of the sea, each land or each coast has not only its peculiar plants or animals, but also harbours many of the organic forms of the neighbouring countries or conterminous shores; as the tropical organisations gradually pass into those of the temperate zones, and these again merge into those of the polar regions, so also the stream of life has from the first flowed uninterruptedly, in gradually changing forms, through every following age. New genera and species have arisen, and others have disap- peared, some after a comparatively short duration, others after having outlasted several formations ; but every extinct form has but made way for others, and thus each period has not only witnessed the decay of many previously flourishing genera and species, but has also marked a new creation. No doubt the numerous local disturbances above mentioned have frequently broken the chain of created beings ; but a gradual progress from related to related forms, a continuous development from lower to more highly organised species, genera, orders, and classes, has from the beginning been the general and constant law of organic life. Universal destructions of existing forms, revolutions covering the whole surface of the earth with ruin, have most assuredly never occurred in the annals of our globe. Nor must it be supposed that the whole scale of sedi- mentary formations is to be found superimposed in one spot ; for as in our times new strata are chiefly growing at the mouths of rivers, or where submarine currents deposit at the bottom of the ocean the fine mud or sand which is conveyed into the sea by the disintegration of distant mountain chains, so also from the beginning each stratum could only have been deposited in similar localities ; and while it was slowly increasing, and not seldom acquiring colossal dimensions in some parts of the globe, others remained comparatively but SUBTEEKANEAN FORCES. 1 little altered, until new oscillatory movements produced a change in their former position, and opening new paths to the rolling waters, here set bounds to the progress of one formation, and there favoured the deposition of another. A complete study of all the various transformations by fire or water which the surface of our earth has undergone would require an elaborate treatise of geology, and lies far beyond the scope or the pretensions of a popular volume which is chiefly devoted to the description of caves and mines. But I should be neglecting some of the most interesting features of the subterranean world, were I to omit all mention of the fossils imbedded in its various strata ; of its internal heat ; of the upheavals and subsidences which have played so con- spicuous a part in the history of the earth-rind, and are still proceeding at the present day ; of the water percolating or flowing beneath the earth's crust, and finally of the volcanoes and earthquakes, which prove to us that the ancient sub- terranean fires, far from being extinct, are still as powerful as ever in remodelling its surface. THE SUBTERRANEAN WOKF^D. CHAPTER II. FOSSILS. General Eemarks — Eozoon Canadense — Trilobites — Braehiopods — Pterichthys Milleri — Oldest Eeptiles —Wonderful Preservation of Colour in Petrified Shells — Primseval Corals and Sponges — Sea-lilies — Orthoceratites and Ammonites — Belemnites — Ichthyosaurus and Plesiosaums — Pterodactyli — Iguanodon • — Tertiary Quadrupeds — Dinotherium — Colossoehelys Atlas — Megatherium — Mylodon — Gly ptodon — Mammoth — Mastodon — Sivatherium Giganteum — Fossil Ripple-marks, Rain-drops, and Pootprints — Harmony has reigned from the beginning. THE fossil remains of plants and animals, which, have successively flourished and passed away since the first dawn of organic life, occupy a prominent place among the wonders of the subterranean world. A medal that has sur- vived the ruin of empires is no doubt a venerable relic, but it seems to have been struck but yesterday when compared with a shell or a leaf that has been buried millions of years ago in the drift of the primeval ocean, and now serves the geologist as a waymark through the past epochs of the earth's history. If we examine the condition in which the fossils have been preserved in the strata successively deposited on the surface of our globe, we find that in general only parts of the original plant or animal have escaped destruction, and in these fragments also the primitive substance has often been replaced by other materials, so that only their form or their impression has triumphed over time. While soft and delicate textures have either been utterly swept away, or could only be preserved under the rarest circumstances (as, for instance, the insects and fiowers inclosed in amber), a greater degree of hardness or solidity naturally gave a better chance of escaping destruction. Thus among plants the most fre- quent fossil-remains are furnished by stems, roots, branches. KXTIXCTIDN OF SPECIES. 9 fruit- stones, leaves; and, among- animals, by corals, sliells, calcareous crusts, teeth, scales, and bones. But the few niemorials that have thns survived the lapse of ages enable ns to form some idea of the multitudes that have entirely perished ; and the petrified shell of the Ammonite, or the AMMOXITJiS IlEXLEYI IJIIDDLE LIAS). jointed arms of the Encrinite, are proofs of the existence of the world of tiny beings which served them for their nour- ishment and have been utterly swept away. If we consider that the number of all the known species of fossil plants hardly amounts to 3,000, while the Flora of the present day, as far as it has been examined by systematical botanists, numbers at least 250,000 species; that the host of living insects is probably still more numerous, although not much more than 1,500 extinct species of this class are known to us ; and that, finally, the remains of all the extinct crustaceous fishes, reptiles, and warm-blooded animals are far outnum- bered by the species actually living — we may fVjrm some idea of the vast miiltitudes that have left no trace behind, and whose total loss will for ever confine within narrow limits our knowledge of the past phases of organic creation. This loss appears still greater when we consider the enormous extent of time during which the fossils known to us have successively existed, and that a part only of the comparatively small num- ber of the orders, genera, and species to which they belong existed at one and the same epoeJi. But as, owing to the hard texture and mode of life which are so eminently favour- able for the preservation of shells, we have been enabled to collect about 11,000 fossil species, a number not much 10 THE SUBTEEEANEAN WOELD. inferior to that of tlie molluscs of the present day, we may justly conclude that the more perishable forms of life, of which, consequently, fewer vestiges hare been preserved, were comparatively as numerous, and that ever since the first dawn of organic life our earth has borne an immense variety of plants and animals. Though comparatively but few species have been preserved, yet sometimes the accumulation of fossil remains is truly astonishing. In the carboniferous strata we not seldom find more than one hundred beds of coal interstratified with sandstones, shales, and limestones, and extending for miles and miles in every direction. How luxuriant must have been the growth of the forests that could produce- masses such as these, and what countless multitudes of herbivorous insects must have fed upon their foliage or afforded food to carnivorous hordes scarcely less numerous than themselves ! The remains of corals, encrinites, and shells often form the greater part of whole mountain ranges, and, what is stiU more remarkable, mighty strata of limestone or flint are not seldom almost entirely composed of the aggregated remains of microscopical animals. After these remarks on fossils in general, I will now briefly point out some of the most striking of the species so preserved to us as they successively appeared upon the stage of life. In the Lower Laurentian Eocks, the most ancient strata knovm, only one fossil has hitherto been found. The Eozoon canadense, as it has been called, belonged to the Rhizopods, which occupy about the lowest grade in the scale of animal existence. Its massive skeletons, composed of innumerable cells, would seem to have extended themselves over submarine rocks, their base upwards of twelve inches in width and their thickness from four to six inches. Such is the antiquity of the Eozoon that the distance of time which separated it from the Trilobites of the Cambrian formation may be equal to the vast period which elapsed between these and the Ter- tiary ages. In other words, it is beyond our imagination to conceive. In the next following Cambrian formation we find, besides some zoophytes and shells, a number of Trilobites, which. COi\DITION OF THE SILURIAX OCEAN. 11 however, appear to have been most abundant in the Sikirian seas, where they probably swarmed as abundantly as the crabs and shrimps in the waters of the present age. Few fossils are more curious than these stranp-e crustaceans. TltlLODriE. JIAGXIFIFn E"\Ti: OK TRiTjicrrE. which so widely differ from their modern relatives. The jointed carapace is divided into three lobes, the middle pro- minent one forming the axis of the body, while the lateral ones were free appendages, under which the soft meinbrana- ceous swimmijig feet were concealed. Large eyes, resembling those of a dragon-fly, projected from the odd crescent-shaped head, and, being composed of many hundred spherical facets, commanded a wide view of the horizon. Provided with such complicated organs of vision, the helpless animal could be- times perceive the approaching euemj-, or more easily espy its prey, consisting, most likely, of the smaller marine anne- lides or molluscs. From the structure of these remarkable eyes we may conclude that the waters of the old Cambrian or Silurian Ocean were as limpid as those of the present seas, and that the natural relations of light to the eye and of the eye to light cannot have greatly changed since that period. Many, if not all, of the Trilobites were capable of rolling themselves up into a ball, like wood-lice ; and ac- cordingly it is found that in many of them the contour of the head and tail is so constructed that they fit accurately when rolled up. Most probably the Trilolntes either swam in an inverted position, the belly upwards, or crawled slowly 12 THE SUBTEBRANEAN WORLD. along at the bottom of the shallow coast waters, where they lived gregariously in vast numbers. Contemporaneous with the Trilobites were the Eurypterids, which vary from one foot to five or six feet in length. One of the most strikino- characteristics of this remarkable order of crustaceans is the formidable pair of pincers with which they were armed. As their whole structure shows them to PTERYOOXrS ACUhriNATirs (EURYI'TERID). SFIlilFER PRINCEPS (DHArJiK ))'0D). have been active swimmers, they must have made consider- able havoc among the smaller fry of the Devonian and Silurian seas. Then also abounded in hundreds of species the Brachiopods, a class of molluscs now but feebly represented by a scanty remnant. The greater part of the interior of the shell con- sisting of two unequal valves, is occupied with branching SILURIAN FISHES. 13 arms, furnished witli cilia, which cause a constant current to flow towards the mouth of the moUusc, and thus provide for its nourishment. The arms, as in the family of the Spiriferidse, are sometimes supported by calcareous skeletons, arranged like loops or spirals. Some Brachiopods are attached to stones, like oysters ; in others the larger valve is perforated, and a sinewy kind of foot, passing through the aperture, serves as a holdfast to the animal. Most of these helpless creatures did not survive the Car- boniferous period, but the Terebratulse, which still have their representatives in the modern seas, existed even then, so that their genealogical tree may justly boast of a very high antiquity. The fishes, of which the oldest known specimen has been found in the Upper Silurian group (Lower Ludlow), become more frequent in the next following Devonian epoch, where they appear in a variety of wonderful forms, widely different from those of the present day. While in nearly all the existing fishes the scales are fiexible, and generally either of a more or less circular form (cycloid), as in the salmon, herring, roach, &c., or provided with comb-like teeth, pro- jecting from the posterior margin (ctenoid), as in the sole or perch, the fishes of the Devonian, Permian, and Carboniferous periods were decked with hard bony scales, either covered with a brilliant enamel, as in our sturgeons (ganoid), and arranged in regular rows, the posterior edges of each slightly overlapping the anterior ones of the next, or irregular in their shape, and separately imbedded in the skin (placoid), as in the sharks and rays of the present day. With rare exceptions their skeleton was cartilaginous ; but the less per- fect ossification of their bones was amply compensated by the solid texture of their enamelled coat of mail, which afforded them a better protection against enemies and injuries from without than is possessed by any bony-skeletoned fish of our days. They were, in fact, comparatively as well prepared for a hostile encounter as an ancient knight in armour, or as one of our modern iron-plated war ships. One of the most remarkable of these mail-clad Ganoids was the Pterichthys Milleri of the Old Eed Sandstone of Scotland. In most of 14 THE SUBTERRANEAN WORLD. our fishes the pectoral fins are but weakly developed ; here they constitute real arms, moved by strong muscles, and resembling the paddle of the turtle. PTKTacnTHTS MILLERI — RESTORED. (OLD RED .SANDSTONE OF SCOTLAND.) Besides the enormous masses of vegetable matter which distinguish the Carboniferous period, the stone beds of that formation liliewise contain a vast number of animal remains. From the reptiles and fishes down to the corals and sponges, many new families, genera, and species crowd upon the scene, while many of the previ(jusly flourishing races have either entirely disappeared, or are evidently declining. Thus the Trilobites, formerly so numerous, are reduced to a few species in the Carboniferous period, and vanish towards its close. It 18 1-7 the oldest known reptiles were found in the coal field of Saarbrlick, in the centre of spheroidal concretions of THE PERMIAN GROUP. 15 clay iron-stone, which not only faithfully preserved the skulls, teeth, and the greater portions of the skeletons of these ancient lizards, but even a large part of their skin, con- sisting of long, narrow, wedge-shaped, tile-like, and horny scales, arranged in rows. What a lesson for human pride ! The pyramid of the Pharaoh Cheops, reared by the labour of thousands of slaves, has been unable to preserve his remains from spoliation even for the short space of a few thousand years, and here a vile reptile has been safely imbedded in a sarcophagus of iron ore during the vast period of many geological formations. Still more recently (1854) other wonders have been brought to light in the clay iron-stone of Saarbriick. The wing of a grasshopper, with all its nerves as distinctly marked as if the creature had been hopping about but yesterday, some white ants or termites (now confined to the warmer regions of the globe), a beetle, and several cockroaches, give us some idea of the insects that lived at the time when our coal-beds were forming. Another highly interesting circumstance, re- lating to the fossils of that distant period, is that in several of them the patterns of their colouring have been preserved. Thus Terehratula hastata often retains the marks of the original coloured stripes which ornamented the living shell. In Aviculopecten suhlohatus dark stripes alternate with a light ground, and wavy blotches are displayed in Pleurotomaria carinata. From these facts Professor Forbes inferred that the depth of the seas in which the Mountain Limestone was formed did not exceed fifty fathoms, as in the existing seas the Testacea, which have shells and well-defined patterns, rarely inhabit a greater depth. The Ma'gnesian Limestone or Permian group is remarkable chiefly for the vast number of fishes that have been found in some of its members, such as the marl slate of Durham and the Kupferschiefer, or copper slate, of Thuring^a. From the curved form of their impressions, as if they had been spasmodically contracted, the fossil fish of the latter locality are supposed to have perished by a sudden death before they sank down into the mud in which thej' were entombed. Probably the copper which impregnates the stratum in which they occur is con- nected with this phenomenon. Mighty volcanic eruptions 16 THE SCBTEKKAXEAX WORLD. corrupted the water with poisonous metallic salts, and de- stroyed in a short time whole legions of its finny inhabitants. From the earliest ages the corals play a conspicuous part in fossil history ; and as in our days we find them encircling- islands and fringing continents with huge ramparts of lime- stone, so many an ancient reef, now far inland, and raised several thousand feet above the level of the sea, bears witness to the vast terrestrial changes that have taken place since it was first piled up by the growth of countless zoophytes. SiriiOXTA CO^TA lA — VO SPONCi; (OHKRX ^AXIl, WAIiMIXSTRK) With regard to the dimensions of the fossil corals we do not find that any of them exceeded in size their modern relatives ; but tlicii' Cfjnstruction was wideh' different. rzTrx(isrox(;iD,E axd lrixoids. 17 Tlie fossil sijoiiges of the primitive seas are likewise very unlike those of the present da^y. Thus in all the ancient strata we find abnudant spongidao Tvith a stony skeleton, while all the modern spono-es I'lossess a horny frame. The Petrosjjongida-, or stone sponges, which hare long since disappeared, are frequently shapeless masses ; Imt a large number are cup-shaped, -svith a central tubular cavity, lined, as Avell as the outer surface, with pores more or less regularly an-anged. The Crinoids, or Sea-lilies, now almost entirely extinct, were » (I\ru.«chGlkalk, (ffTrnan;'.) PEN'T'AiTJXL's i;i:rAi;M;s. extremely common in tlie j)i*iine'\'al seas. Unlike our modern sea-stars, to "wliich tliej^ are allies, Un:y cliil injt move about c 18 THE SUBTEKRANEAX WORLD. freely from place to place, but were affixed, like flowers, to a slender flexible stalk, composed of numeroris calcareous joints connected together by a flesby coat. The Carboniferous Mountain Limestone is loaded with their remains, and the Encrinug liUiformis is one of the leading fossils of the Mus- chelkalk of the Triassic group. The Pentacrinus briareus is of more modern date, and occurs in tangled masses, forming thin beds of considerable extent in the Lower Lias. This beautiful Crinoid, with its innumerable tentacular arms, appears to have been frequently attached to the drift wood of the Liassic sea, like the floating barnacles of the present day. In the stiU more recent Chalk group is found a re- markable form of star-fish, the Marsupites ornatus, which resembles in all respects the Crinoids, except that it is not and never was provided with a stem. It seems to have been rolled lazily to and fro, by the influence of the waves, at the bottom of the sea, and to have been anchored in its place by the action of gravity alone. Of all the changes that have taken place in organic life, none perhaps are more remarkable than the transforma- tions which the Cephalopod molluscs have undergone during the various geological eras. In the more ancient Palteozoic seas flourished the Orthoceratites,or straight- chambered shells, resembling a nau- tihis uncoiled. In the Carboniferous ages the Goniatites acquired their highest develoi")ment. These shells were spirally wound, having the lobes of the chambers free from lateral denticulations or crenatures, so as to form continuous and uninterrupted outlines. Both Orthoceratites and Goniatites disappear in the Triassic times, and are replaced by hosts of Ammonites, which successively flourished in more than GOO species, and are characterised by an external siph(.)n and chambers of com- plicated, often foliated, pattern. This foliated structure gives a remarkable character to the intersection of the chamber partitions with the shell, and must have added greatly to the jtAnsurri'ES OKNATrs. chalk. AMMONITES AKD BELEJLNITES. 19 strength of the shell, which was alwa^ys delicate and often very beautiful. The Ammonites, which made their first appearance towards the end of the Triassic period, al)Ounded in the Oolitic and Cretaceous periods, and were replaced by new f(_^rms before the Tertiary Ijeds were deposited. Among these we find the Anri/loceras gigos, which may 1je regarded as an Ammonite partially unrolled, and the Turril'des titber- ndntus, which has the form arid peculiar symmetry of a univalve shell. TL"i;i;u,rn:s ti in several of the older rocks, especially the Lias and Oolite, Belemnites are frequently met with. These singular dart- or arrow-shaped fossils were supposed by the ancients to be the thunderbolts of Jove, but are now known to be the petrified internal bones of a race of voracious cuttle-fishes, whose importance in the Oolitic or Cretaceous Seas may be judged of by the frequency of their remains and tlie I 20 species that have been hitherto discovered. Belemnites two feet long have been found, so that, to judge by analogies, tJie anima.ls to which tJiey lielouged as cuttle- 20 THE SUBTEKRANEASf WORLD. bones must have measured eighteen or twenty feet from end to end. Provided with prehensile hooks on their long arms, and with a formidable parrot-like bill, these huge creatures must have proved most dangerous antagonists, even to the well-protected fishes that lived in the same seas. But of all the denizens of the Mesozoic Ocean none were more powerful than the large marine or enaliosaurian reptiles, which, flourish- ing throughout the whole of the Triassic period, were lords of all they surveyed down to the end of the Cretaceous epoch. First among these monsters appears the gigantic Ichthyosaurus, which has been found no less than forty feet lOHTHYOSAUarS COMMUJtIS. long — a creature half fish, half lizard, and combining, in strange juxtaposition, the snout of the porpoise, the teeth of the crocodile, and the paddles of the whale. But the most remarkable of its features is the eye, surpassing a man's head in size, and wonderfully adapted for vision both far and near. In the quarries of Caen in Normandy, at Lyme Regis in Dorsetshire, and particularly at Kloster Banz in Franeonia, where the largest known specimen has been discovered, entire skeletons of the formidable Ichthyosaurus have been ex- humed from the Liassic shale — memorials of the ages long since past, when lands now far removed from the ocean still lay at the bottom of the sea, a.nd formed the domain of gigantic lizards. The enormous jaw-bones of the Ichthyo- sauri, which in the full-grown animal could be opened seven feet wide, were armed along their whole length with powerful conical teeth, showing them to have been carnivorous, and the half-digested remains of fishes and reptiles found within their skeletons indicate the precise nature of their food. The size of the swallowed object proves also that the cavity of PTERODACTVLES. 21 the stomach must have corresponded with the wide opening ol the jaws.. Thus powerfully equipped for offensiYe warfare ; excellent swimmers from their compressed cuneiform trunk, their long broad paddles, and their stout vertical tail-fiu ; provided, moreover, with eyes capable of piercing the dim light of the ocean depths, the}' must have been formidable indeed to the contem- poraneous fishes. The Ichthyosaurus was admirably formed for cleaving the waves, of an agitated sea ; but the Plesiosaurus was equally well organised for pursuing its prey in shallow creeks and bays defended from heavy breakers. Its long swan dike neck no doubt enabled it to drag many a victim from its hid- ing-place. While these huge lizards were the terror of the seas, the Pterodactyles, a race of winged lizards, armed with long jaws and sharp teeth, hovered in the air. With the ex- ception of the greatly elongated fifth finger, to which, as well as to the whole length of the arm and body, the membranous wing or organ of flight was attached, the fingers of this strange animal were provided with sharp claws, so that it was probably enabled, like the bat, to sus- pend itself from precipitous rock-walls. It is a remarkable fact, that, whereas the Pterodactyles of PLESIOSAURUS DOLICHODEIKUJ^ (British Miiseiim .Found in the Lias of Street, near GiastODbnry.) •22 THE SUBTERRANEAN WORLD. the older Lias beds did not exceed ten or twelve inches in length, the later forms, found fossil in the Greensand and Wealden beds of the Lower Cretaceous formation, must have been at least 16^ feet long. That these reptiles were not the only vertebrated animals capable of hovering in the air at the time when the huge Ichthyosaurus was lord of the seas, is proved by a bird about the size of a rook, which was discovered in 1862, in the lithographic slate of Solenhofen in Bavaria, a stone-bed belonging to the period of the Upper Oolite. The skeleton of this valuable specimen, now in the British Museum, is almost entire, with the exception of the head, and retains even its feathers. Still older fossil mam- malia have been found near Stuttgard, in the uppermost bed of the Triassic deposits, and in the Lower Oolite of Oxfordshire. These interesting remains, which carry back the existence of the mammals to a very remote period, belong to small marsupial, or opossum-like, animals. The jaws, which are the principal parts preserved, are exceedingly minute, and re- markable for the number and distribution of their teeth, which prove them to have been either insectivorous or rodent. The remains of the Ichthyosauri and Plesiosauri occur chiefly in the Liassic group, but the more recent Cretaceous (Wealden) formation is distinguished by the presence of still more enormous land saurians. On their massive legs and unwieldy feet these monsters stood much higher than any reptile of our days, and resembled in bulk and stature the elephants of the present world. The carnivorous Megalosaurus (for its sharply serrated teeth indicate this mode of life) appears to have preceded the gigantic Iguanodon, whose dentition denotes a vegetable food. Like the giant sloths of South America — the Mega- therium and the Mylodon — the Iguanodon was provided with a long prehensile tongue and fleshy lips to seize the leaves and branches on which it fed. Professor Owen esti- mates its probable length at between fifty and sixty feet, and to judge by the proportions of its extremities, and par- ticularly of its huge feet, it must have exceeded the bulk of the elephant eightfold. During the following Upper Cretaceous epoch flourished THE DIXOTHEEIUM. 23 the Mosasaurus, a marine saurian, first discovered in the quarries of St. Peter's Mount, near Maestricht,* and supposed to have been twenty-four feet in length. But the supremacy of the reptiles was now drawing to its close, and in the Tertiary period we at length see the Mammalia assume a prominent pla/ee on the scene of life. The oldest of these tertiary quadrupeds differ so widely from those of the present day as to form distinct genera. The Palaeotheriums, for instance, of which there are seventeen species, varying in dimensions from the size of a rhinoceros to that of a hog, combine in their skeleton many of the characters of the tapir, the rhinoceros, and the horse, while the Anoplo- theriums, whose size varied from that of a hare to that of a dwarf ass, resembled in some respects the rhinoceros and the horse, and in others the hippopotamus, the hog, and the camel. In the Miocene epoch many of these more ancient quad- rupeds no longer appear upon the scene, while others still flourish in its upper period along with still existing genera, and with forms long since extinct, such as the Dinotherium. This huge animal is particularly remarkable for its two large and heavy tusks, placed at the extremity of the lower jaw, and curved downwards like those in the upper jaw of the walrus. It was formerly supposed to be an herbivorous cretacean, and to have used its anterior limbs principally in the act of digging for roots. The remains on which these speculations were founded were the huge jaws and shoulder-blade dis- covered at Epplesheim in Hesse Darmstadt ; but an immense pelvis of the animal, measuring six feet in breadth and four andaquarter feet inheight, discovered by Father Sa,nno Solaro, in the department of the Haute Garonne, proves that this supposed aquatic pachyderm was a gigantic marsupial, and that the dependent trunks of the unwieldy animal, instead of se'-'.ing the purpose of anchoring it to the banks of rivers, answered the more homely, but equally important office, of lifting the young into the maternafl pouch. ' The remarkable history of the successive discovery of its bones,' says Pro- fessor Haughton, ' and the change of views consequent there- upon, should teach geologists modesty in the expression of * Chapter XXXVIII. 24 THE SUBTERRANEAN WORLD. their opinion.' During this period also flourished in India, along with many other strange forms of life, the Colossochelys Atlas, a tortoise of the most gigantic proportions, measuring, probably, nearly twenty feet on the curve of the carapace, and dwarfing into insignificance the great Indian tortoise of the present day. The nearer we approach our own times, the greater be- comes the proportion of still existing genera and species; and it is remarkable that as early as the Pliocene epoch we find a geographical distribution of mammaliaa life analogous to that which now characterises the various regions of the earth. Thus the fossil m.onkeys of South America have the nostrils wide apart like all the existing simise of the new world, and fossil monkeys with approximated nostrils, the characteristic mark of aU the old world quadrumana, are exclusively found in Asia and in Europe, where now a small species of monkey is confined to the Eock of Gibraltar, but where, in the Upper Miocene times, large long-armed apes, equalling man in stature, lived in the oak forests of Prance. Thus also South America, where alone sloths and armadilloes exist at the present day, is the only part of the world where, in the younger tertiary rocks, the remains of analogous mammals — the Megatherium, the Mylodon, and the Glyp- todon — have been found. The Mylodon was a colossal sloth, eleven feet long and with a corresponding girth. When we consider the huge size of the pelvis and the massiveness of the limbs, we must needs conclude that Professor Owen could not possibly have given the unwieldy animal a more appropriate surname than that of Tobustus. The Megatherium was of still larger size. Its length was as much as eighteen leet, the breadth of its pelvis was six feet, and the tail, where it was attached to the body, must have measured six feet in circumference. The thigh bone was nearly three times as great as that of the largest known elephant, the bones of the instep and those of the foot being also of corresponding size. The general proportions both of the Megatherium and Mylodon resembled those of the ele- phant, the body being relatively as large, the legs shorter Tllf: MElJATIll-^KlU.M. 25 and thieker, and the neck very little longer. The Mega- therinm may have had a short proboscis, but the Mylodou exhibits no mark of such contrivance. It is evident, from the bulk and construction of these huge animals, that they did not, like the sloths of the present day, crawl along- the under side of the boughs till they had reached a commodious feeding place, but that, firmly seated on the strong tripod of their two hind legs and powerful tail, they uprooted trees or wrenched otf branches with their fore limbs, which were well adapted for grasping the trunk or larger branches of a tree. The long and powerful claws were also, no doubt, useful in the preliminary process of scratching away the soil from the roots of the trees to be prostrated. This task accomplished, the long and curved fore claws would next be applied to the opposite sides of the loosened trunk. ' The tree being thus partly undermined and firmly grappled with, the muscles of the trunk, the pelvis, and hind liuibs, animated by the nervous influence of the unusually large spinal cord, would coudjine their forces with those of the anterior members in the eiforts at prostra- tion. If now we picture to ourseh'es the massive frame of the Megatherium, convulsed with the mighty wrestling, every vibrating tibre reacting upon its bony attachment with a force which the sharp and strong crests and apophyses loudly bespeak, we may suppose that that tree must have been strong indeed which, rocked to and fro, to right and LYr''l'i.iDriN' CLAVir'ES. left, in such an embrace, could long withstand the efforts of its ponderous assailant.' The Glyptodon, a colossal armadillo of the size of an 26 THE SUBTERKAXEAN WOKLD. OX, was covered with a thick heavy tessellated bony armour, which, when detached from the body, resembled the section of a large cask. This harness measured on its curve from head to tail at least six feet, and four feet from side to side, so that a Laplander might have squatted comfortably under its roof. In the superficial deposits of diluvial drift, in Germany and England, in Italy and Spain, in Northern Asia as well as in North America, between the latitudes of 40° and 75°, the bones of the large extinct Pachyderms have been found, and become more and more abundant as we approach the ice-bound regions within the Arctic Circle. The Siberian tundras, and the islands in the Polar Sea beyond, are, above all, so rich in the fossil remains of the Mammoth, or primitive elephant, that its tusks form a not unimportant branch of commerce. Prom the presence of so large an animal in treeless wilds, where now only small rodents or their persecutors, the Arctic fox and snow owl, find the means of subsistence, it has been inferred that Siberia must in those times have enjoyed a tropical climate; but many weighty arguments have been arrayed against this opinion. The musk-ox, it is well known, prefers the stinted herbage of the Arctic regions, while the allied buffalo can only thrive in a warm country, and different species of bears are found in all zones ; so also the primitive elephant was formed for a temperate or cold climate. Instead of being naked, like his living Asiatic and African relations, the Mammoth was covered with a warm clothing, well fitted to brave a low temperature, a fact sufiiciently proved by the carcass of one of these animals which was found, in the year 1803, imbed- ded in a mass of ice on the bank of the Lena in latitude 70°. Its skin was covered first with black bristles, thicker than horse-hair, from twelve to sixteen inches in length, secondly with hair of a reddish-brown colour, about four inches long, and thirdly with wool of the same colour as the hair, about an inch in length. The discoveries of Middendorff on the banks of the Taymur likewise show that in those times the climate of Siberia was by no means tropical, for in latitude 75° 15' he found the trunk of a larch imbedded with the bones of a Mammoth in THE MASTODON. 27 an alluvial stratum fifteen feet above tlie level of tlie sea. Fragments of pine leaves have likewise been extracted from cavities in the molar teeth of a fossil rhinoceros, discovered on the banks of the Wiljui, in latitude 64°. The numerous land and freshwater shells accompanying the Mammoth in the highest latitudes are also, almost without exception, identical with those now existing in Siberia. The Mastodon, though not uncommon among the fossils of the old world, is more abundantly found in North America. The molar teeth of this huge animal, whose grinding surfaces had their crowns studded with conical eminences, more or less resembling the teats of a cow, differed greatly from the flatrcrowned grinders of the Mammoth ; but both had twenty ribs like the living elephant, and must have been similar in size and general appearance. The body of the Mastodon would seem to have been longer, its limbs thicker and shorter, and, perhaps, its form, on the whole, rather approsiching that of the hippopotamus, which it probably resembled also in some of its habits. Its mouth was broader than that of the elephant, and although it was certainly provided with a long trunk, it must have lived on soft succulent food, and it seems to have rarely left the marshes and muddy ponds, in which it would find ample food. The most complete, and probably the largest, specimen of the Mastodon ever found was exhumed in 1846, in the town of Newbury, New York, the length of the skeleton being twenty-five feet, and its height twelve feet. From another specimen, found in the same year, in Warren County, New Jersey, the clay in the interior within the ribs, just where the contents of the stomach might naturally have been looked for, furnished some bushels of vegetable substance. A microscopic examination proved this matter to consist of pieces of small twigs of a coniferous tree of the cypress family, probably the young shoots of the white cedar {Thuja occidentalis) which is still a native of North America. This interesting discovery likewise proves that the climate of North America was then, like that of Siberia, not very diiferent from that of the present day. The most remarkable of the fossil Euminants are found among the deer tribe. The largest of these is the Sivatherium 28 THE SUBTEREANEAN WORLD. gigantewm, discovered in the Tertiary beds of the sub- Himalayan hills. It was a deer with four horns, and, to judge by the size of its bones, must have exceeded tbe elephant in its dimensions. Near this huge ' antlered monarch of the waste ' the extinct Gervus megaceros, found LU the bogs and shallow marls of Ireland, appears as a mere dwarf, in spite of its large branching palmate horns, often weighing eighty pounds, and a corresponding stature far exceeding that of our modern deer. The colossal size of many of the extinct plants and animals might seem to favour the belief that organic life has degene- rated from its former powers; but a survey of existing creation soon proves the vital principle to be as strong and flourishing as ever. No fossil tree has yet been found to equal the towering height of the huge Sequoias and Wellingtonias of California; and though the Horsetails and Clubmosses of the Carboni- ferous ages may well be called colossal when compared with their diminutive representatives of the present day, yet their height by no means exceeded that of the tall bamboo of India. No fossil bivalve is as large as the Tridacna of the tropical seas ; and though our nautilus is a mere pigmy when compared with many of the Ammonites, our naked cuttle- fishes are probably as bulky as those of any of the former geological formations. The living crustaceans and fishes are not inferior to their predecessors in size, and though the giant saurians of the past were much larger than our crocodiles, yet they do not completely dwarf them by com- parison. The extinct Dinornis* far surpassed the ostrich in size, but the Mammoth and the Mastodon find their equal in our elephant ; and though the sloths of the present day are mere pigmies when compared with the Megatherium, yet no extinct mammal attains the size of the Greenland whale. The perfect preservation of so many fossil remains of animals and plants, which enables us to trace the progress of organic life on earth from one vast epoch to another, is surely wonderful enough ; but we must consider it as a still greater wonder that phenomena usually so evanescent as foot-prints, ripple-marks, and rain-prints should in some * Chapter XIX. SUCCESSION OP SPECIES. 29 cases Lave been permanently engraved in stone, and appear as distinct after millions of years as if their traces liad been left but yesterday. All these marks were at first printed on soft argillaceous mud, on the sea-shore, or on the borders of lakes and rivers, which retained them as they became dry. Sand or clay having then been drifted into the mould by the wind, or deposited in its cavity by the next tide, a permanent cast was made, indented in the lower stratum and standing out in relief on the upper one. Thus rain-drops on greenish slates of the Coal period, with several worm tracks, such as usually accompany rain-marks on the recent mud of modern beaches, have been discovered near Sydney, in Cape Breton. As the drops resemble in their average size those which now fall from the clouds, we may presume that the atmosphere of the Carboniferous period corresponded in density with that now investing the globe, and that different currents of air varied then as now in temperature, so as, by their mixture, to give rise to the condensation of aqueous vapour. In like manner it has been possible to detect the foot- prints of reptiles, even in shales as old as the Cambrian formation, and to follow their trail as they walked or crawled along. In the Upper New Red Sandstone (Lower Trias), near Hildburghausen, in Saxony, a strange unknown animal, supposed to belong to the frog order, has left foot-prints bearing a striking resemblance to the impressions made by a human hand ; and in the still older red sandstone of Connecticut, a gigantic bird has marked a foot four times larger than that of the ostrich. It existed long before the Ichthyosaurus was seen on earth, and yet by a singular chance its traces, printed on a foundation proverbially un- stable, have outlived the wreck of so many ages. However brief and defective the foregoing review of the fossil world may have been, it has still suiEced to point out the existence on our planet of so many habitable surfaces, each distinct in time, and peopled with its peculiar races of aquatic and terrestrial beings, aU admirably fitted for the new states of the globe as they arose, or they would not BO THE SUBTERKANEAN WORLD. have increased and multiplied and endured for indefinite- periods. ' Tlie proofs now accumulated,' says Sir Charles Lyell, ' of the close analogy between extinct and recent species are such as to leave no doubt on the mind that the same harmony of parts and beauty of contrivance which we admire in the living creation has equally characterised the organic world at remote periods. Thus, as we increase our knowledge of the inexhaustible variety displayed in living nature, our admiration is multiplied by the reflection that it is only the last of a great series of pre-existing creations, of which we cannot estimate the number or limit in times past.' 31 CHAPTEE III. SUBTEEEANBAN HEAT. Zone of invariable Temperature — Increasing Temperature of the Earth at a greater Depth — Proofs found in Mines and Artesian Wells, in Hot Springs and Volcanic Eruptions — The whole Earth probably at one time a fluid mass. BORN neither to soar into the air, nor to inhabit the deep waters, nor to pass his life in subterranean dark- ness, man is unable to depart to any considerable distance from the earth's surface. If he ascends in a balloon, he soon reaches the limits where the rarefied atmosphere renders breathing impossible ; a few thousand feet limit his efforts to pierce the earth's crust ; and should he be cast out into the sea, he is soon drowned. But beyond the limits to which his body is confined, his mind soars into space, and plunging into the unknown interior of our globe, seeks to unravel the mystery of its formation. In the following pages I purpose briefly to point out the circumstances which guide him in his speculations, and enable him to roam, at least in spirit, through the profound abysses of the subterranean world. As we all know, the temperature of the atmosphere soon communicates its changes to the surface of the earth ; and our meadows, which when waxmed by the rays of the sun are green and covered with flowers, harden in winter into a lifeless plain. But the influence of the sun's heat upon the soil is merely superficial, so that in the temperate zones the annual fluctuations of the thermometer are no longer per- ceptible at a depth of from 60 to 80 feet. Thus, in the cellars of the Parisian observatory, a thermo- meter, placed many years ago 86 feet below the surface, invariably indicates + 1 1°7 Celsius ; the summer above may be ever so intensely hot, or the winter ever so cold, the 32 THE SUBTERKANKAN WORLD. column of mercury never deviates a hair's breadtli from the height it has once attained. Below these limits the warmth of the earth graduallj' increases— a fact placed beyond all doubt by the innumerable observations that have been made in mines, and during the boring of Artesian wells. For wherever sinkings have been made, a rising of the thermometer has always been found bo take place as the auger penetrates to a greater depth below the surface. Thus, to cite but a few examples, the temperature of the Artesian well of Grenelle in Paris, which, at a depth of 917 French feet, amounted to + 22°2 C, increased at the depth of 1,556 feet to + 26°43, and the water, which now gushes forth from the depth of 1,684 feet, constantly maintains the same lukewarm temperature of + 27°70. During the boring of the well of Neusalzwerk, in West- phalia, the temperature rose at the various depths of 680, 1,285, and 1,935 feet from +19°7 C. to + 27°6 and -|-31°4, until, finally, when the depth of 2,144 feet was attained, the saline spring issued forth with a constant temperature of + 33°6. As from the experience acquired in mines and Artesian wells, the temperature is found to increase by one degree for about every successive 80 or 100 feet, the internal warmth of the earth, supposing it to increase in the same proportion towards the centre, would, at the depth of 10,000 feet, be equal to that of boiling water, and at that of 80 or 100 miles sufficiently great to melt the hardest rock. Whether this steady increase really takes place is of course only matter of conjecture ; but the history of hot springs and volcanic eruptions shows us that everywhere a very high degree of heat exists at considerable depths below the surface. Most springs in the temperate zone, without being warm in a remarkable degree, still possess a higher temperature than the average warmth of the air in the locality where they gush forth, while in the tropical zone they are fre- quently cooler— a proof that in both cases they issue from a depth independent of the fluctuating atmospherical influences of the surface. While these cool or cold springs, spread in immense nunibers over the earth, attest the existence every- where of a subterranean source of heat, the warm and hot EXTENT OF VOLCANIC ACTIOX. 33 springs remind us of its intensity at more considerable depths. These thermal sources are confined to no climate, for in the cold land of the Tschuktschi, where the soil must be perpetually frozen to a depth of several hundred feet, boiling water is foand to gush forth, as well as in the tropical Feejee Islands. The hot springs, though of frequent occurrence in all parts of the world, are not the only or principal vents of subterranean heat. Far greater quantities of caloric are constantly pouring forth from the numerous volcanoes and solfataras, which are likewise distributed all over the surface of the globe. The violent convulsions which attend every outflow of lava are proofs that these torrents of liquid stone must have been forced upwards from a far greater depth than the water of the hot springs. The temperature necessary for their production likewise points to this fact, for to melt stones a heat of at least 2,000° C. is required. But volcanoes, like hot springs, are found in every zone ; beyond the Arctic Circle, as well as in the most southern land attained by Sir James Ross in his memorable voyage. They line the coasts of the Pacific, as well as those of the Sea of Kamtschatka.. They desolate Iceland, as they de- voured Pompeii and Herculaneum; and everywhere they pour forth the same masses of fluid stone; so that the geologist is not able to distinguish the lavas of the Andes chain from those of Etna or Vesuvius. But phenomena so much alike in character, common to all parts of the globe, can hardly be dependent upon mere local circumstances, and speak loudly in favour of the theory which supposes our earth to have been at one time a ball of liquid flre. Wandering through space during a course of unnumbered ages, this huge mass of molten stones and metals gradually cooled, and at length got covered with a solid crust, below which the ancient furnaces are still burning, and striving to burst their fetters. Well may we say with Horace — ' Tncedimus per ignes Suppoaitos cineri doloso.' 34 THE SUBTEEKANEAN WORLD. CHAPTER IV. SUBTEEEANEAN UPHEAVALS AND DEPEESSIONS. Oscillations of the Earth's Surface taking place in the present day — First ascertained in Sweden— -Examples of Contemporaneous Upheaval and Depression in France and England — Probable Causes of the Phenomenon. WHILE the sea and tlie atmospheric ocean are subject to perpetual fluctuations, and the poet justly compares the uncertain tenure of human prosperity with the restless wave or the inconstant wind, the solid earth is generally regarded as the emblem of stability. But an examination of the various strata of aqueous origin which constitute by far the greater part of the actual dry land soon shows the fallacy of this opinion. The fossils of marine origin which occur in so many of our oldest rocks, now situated far above the level of the ocean, must necessarily have been raised from the deep. On the towering Andes, fifteen thousand feet above the tide-marks of the Pacific, the geologist finds sea-shells imbedded in the rock, and high above the snow-line the chamois-hunter of the Alps wonders at the sight of spirally-wonnd Ammonites that once enjoyed life at the bottom of the Liassic Sea. In strata of a more modern date, we find, on the banks of the river Senegal, far inland, large deposits of the Area senilis, a mollusc still living on the neighbouring coast. On the borders of Loch Lomond, twenty feet above the level of the sea, shells of the edible cockle and sea-urchin repose in a layer of brown clay, and the banks of the Forth and of the Clyde, thirty feet higher than the storm tides, inclose remains of common shells of the present period, such as the oyster, the mnssel, and the limpet. Along the shores of the Medi- terranean, at Monte Video and at Valparaiso, in the isles of the Pacific and at the Cape, in California and Haiti, we meet UPHEAVAL AXD DEPRESSION. 35 with similar instances of elevation, which, though geologically recent, may yet be of a sufiiciently ancient date to have preceded the appearance of man on earth. But proofs are not wanting that the upheaving power which has wrought so many changes in the past is still actively employed in remodelling the surface of the earth. This important geological fact was first ascertained on the coastof Sweden, where the peculiar configuration of the shore makes it easy to appreciate slight changes in the relative level of land and water. For the continent is fringed with countless rocky islands, called the ' skar,' within which boats and small vessels sail in smooth water even when the sea without is strongly agitated. But the navigation is very intricate, and the pilot must possess a perfect knowledge of the breadth and depth of every narrow channel, and the position of innumerable sunken rocks. On such a coast even a slight change of level could not fail to become known to the mariner, and to attract the attention of the learned, as soon as the book of nature began to be more accurately studied. Early in the last century the Swedish naturalist Celsius collected numerous observations, all pointing to the fact of a slow elevation of the land. Eocks both on the shore of the Baltic and the Grerman Ocean, known to have been once sunken reefs, were in his time above water; small islands in the Gulf of Bothnia had been joined to the continent, and old fishing grounds deserted, as being too shallow or entirely dried up. These changes of level, which he estimated at about three feet in a century, Celsius attributed to a sinking of the waters of the Baltic, owing possibly to the channel, by which it dis- charges its surplus waters into the Atlantic, having been gradually widened and deepened by the waves and currents. But the lowering of level would in that case have been uniform and universal over that inland sea, and the waters could not have sunk at Torneo while they retained their former level at Copenhagen, Wismar, Stralsund, and other towns which are now as close to the water's edge as at the time of their foundation. Playfair (1802) and Leopold von Buch (1807) first attributed the change of level to the slow and insensible rising of the land, and the subsequent in- IJ 2 36 THE SUBTEEKANEAN WOKLD. vestigations of Sir Charles Lyell in 1834 have placed the fact beyond a doubt. The attention of geologists having once been directed to the partial upheaval of the Scandinavian peninsula, similar facts were soon pointed out in other countries. At Bourg- neuf, near La Eochelle, the remains of a ship vprecked on an oyster bank in the year 1752, now lie in a cultivated field, fifteen feet above the level of the sea ; and, within a period of twenty-five years the parish has gained at least 1,500 acres, a very acceptable gift of the subterranean plutonic power. Port Bahaud, where formerly the Dutchmen used to take in cargoes of salt, is now 9,000 feet from the sea, and the Island of Olonne is at present surrounded only by swamps and meadows. These and similar phenomena, such as the constant rise of the chalk cliffs at Marennes, cannot possibly be explained by recent driffcings, but evidently proceed from a slow upheaval of the coasts and the adjacent sea-bed. On the opposite shores of the Atlantic, we find New- foundland undergoing a similar process of elevation ; for cliffs over which, thirty or forty years ago, schooners used to sail with perfect safety, are now quite close to the surface ; and in the Pacific the depth of the channel leading to the port of Honolulu is gradually decreasing from the same cause. While many coasts thus show signs of progressive elevation, others afford no less striking proofs of subsidence, frequently in close proximity to regions of upheaval. Thus on the south-west coast of England, in Cornwall, Devon, and Somerset, submarine forests, consisting of the species still flourishing in the neighbourhood, are of such frequent occurrence that, according to Sir Henry de la Beche, ' it is difiicult not to find traces of them at the mouths of all the numerous valleys which open upon the sea.' Sometimes they are covered with mud or sand, and generally the roots are found in the situation where they originally grew, while the trunks have been horizontally levelled. At Bann Bridge, specimens of ancient Eoman pottery have been discovered twelve feet below the level of the sea, and the remains of an old Eoman road, now submerged six feet deep, prove that the subsidence of the land has been going on since the times of Julius Csesar and Agricola. POSITION OF STRATA. 37 On tlie east coast tlie plienoineiion is still more striking, particularly in the Wash, that shallow bay between Lincoln- shire and Norfolk on whose opposite shores a submarine forest extends, the trunks and stubbles of which become apparent at ebb-tide. On the coasts of Normandy and Brittany we likewise find traces of depression, pointing to some future time when perhaps many a bluff headland, now boldly fronting the ocean, may have disappeared beneath the waves. Huts of the Esquimaux and of the early Danish colonists on the coast of Greenland, now submerged at high tide, could not possibly have been originally constructed in so inconvenient a situation ; and at Puynipet, in the South Sea, habitations sunk beneath the water likewise prove a gradual subsidence of the land. On many «oasts and islands modern scientific explorers have hewn marks in the rock, to enable future generations to judge of the changes which are slowly but surely altering the configuration of the land and tracing new boundaries to the ocean. Had our forefathers left us similar memorials, we should know much more about the oscillatory movements of the earth-rind than we know now; but, unfortunately, experimental natural philosophy is but of recent date, and the marks chiselled out upon the Swedish rocks in the years 1731 and 1752 are the earliest records by which the chrono- logical progress of elevation or subsidence can be distinctly ascertained. This phenomenon, which has played so important a part in the physical annals of our globe, having once been accu- rately determined, enables the geologist to explain many facts for which, before it became known, it was impossible to account. We now need not wonder at seeing sea-shells imbedded in the highest mountains or buried hundreds of fathoms under the ground, at alternating layers of marine and sweet- water deposits being frequently storied one above the other, or at originally horizontal strata being now found at every possible angle of inclination. The imperceptible slowness with which many of these vast changes are actually taking place warrants the inference that 38 THE SUBTEERAXEAN WOELD. violent volcanic revolutions have no doubt been far less instrumental in moulding tbe eartb-rind to its present form than tbe slow oscillatory movements of elevation and de- pression wbicb from time immemorial have been constantly- altering its surface. The causes of these oscillatory movements are stiU very imperfectly known, though a probable hypothesis attributes them to the expansion by increased temperature of extensive deep-seated masses of matter. As the elevation of some tracts seems to coincide with the proportionate depression of others at a greater or less distance, these alternating upheavals and subsidences may possibly be the result rather of the lateral shifting of the flow of heat from one mass of subterranean matter to a neighbouring mass than of its positive increase on the whole. ' Such a lateral diversion of the outward flow of heat,' says Mr. Poulett Scrope, ' we may presume to be caused by the deposition over cei-taiu areas of thick newly-formed beds of any m.atter imperfectly con- ducting heat, like sedimentary sands, gravels, clays, shales, or calcareous mud, by which the outward transmission of heat being cheeked, it must accumulate beneath, while a por- tion of it will pass off laterally to augment the temperature of mineral matter in neighbouring areas ; just as- the water of a spring, if its usual issue is blocked up, will accumulate in the fissures or pores of the rock containing it, until it finds a vent on either side and at a higher level. Owing to this increase, the resistance opposed by the overlying rocks in that quarter may be sooner or later overcome, and their elevation brought about, through the dilatation of the mineral matter beneath.' 39 CHAPTER V. SUBTEEEANEAN WATEES AND AETESIAN WELLS. Subterranean Distribution of the Waters — Admirable Provisiona of Nature — Hydrostatic Laws regulating tbe Flow of Springs — Thermal Springs— Inter- mittent Springs — The Geysir— Bunsen's Theory— Artesian Wells — Le Puits de G-renelle — Deep Borings — Various Uses of Artesian Wells — Artesian Welis in Venice and in the Desert of Sahara. IN every zone the evaporating power of tlie sun raises from the surface of the ocean vapours, vrhich hover in the air until, condensed by cold, they descend in rain upon the earth. Here part of them are soon restored to the sea by the swollen rivers ; another part is once more volatilised ; but by far the larger quantity finds its slow way into the bowels of the earth, where it serves for the perennial supply of wells and springs. The distribution of these subterranean waters, and the simple laws which regulate their circulation, afford us one of the most interesting glimpses into the physical economy of our globe. We know that the greater part of the earth's surface is composed of stratified rocks, or alternate beds of impermeable clay and porous limestone or sand, which were originally deposited in horizontal layers, but have since been more or less displaced and set on edge by upheaving forces. Wherever permeable beds of limestone or sand crop out on the surface of the land, the residuary portions of rain-water which are not disposed of by floods or by evaporation, must necessarily penetrate into the pores and fissures, and descend lower and lower, until they finally reach an impermeable stratum which forbids their further progress to a greater depth. The granite, gneiss, porphyry, lava, and other unstratified and crystalline rocks of igneous origin, which cover about a 40 THE SUBTERRANEAN WOUtV. third part of the habitable globe, are likewise intersected by innumerable fissures and interstices, whicli, in a similar manner, collect and transmit rain-water. Thus the plutonic or volcanic forces which, have gradually- moulded the dry land into its present form have also provided it with the necessary filters, drains, reservoirs, and conduits, for the constant replenishment of springs, brooks, and rivers. As every porous layer is more or less saturated with moisture, the stratified rocks are frequently tr9,versed at various depths by distinct sheets of water, or rather, in most cases, by permanently drenched or waterlogged sheets of chalk or sand. Thus, in a boring undertaken in search of coal at St. Nicolas d'Aliermont, near Dieppe, no less than seven very abundant aquiferous layers or beds of stone were met with from about 75 to 1,000 feet below the surface. In an Artesian boring at Paris, five distinct sheets of water, each of them capable of ascension, were ascertained; and similar perforations executed in the United States, and other countries, have in the same manner traversed successive stages of aqueous deposits. Thus there can be no doubt that vast quantities of water are everywhere accumulated in the porous strata of which a great part of the superficial earth-rind is composed, the rapidity with which they circulate varying of course with the amount of hydrostatic pressure to which they are subjected, and the more or less porous and permeable nature of the beds through which they percolate. Were the ground we stand on composed of transparent crystal, and the subter- ranean water-courses tinged with some vivid colour, we should then see the upper earth-crust traversed in every direction by aqueous veins, and frequently as saturated with water as the internal parts of our body are with blood. But Nature not only perennially feeds our springs and brooks from the inexhaustible fountains of the deep ; it is also one of her infinitely wise provisions that the same water which, if placed in casks or open tanks, becomes putrid, continues fresh so bng as it remains in the cavities and interstices of the terrestrial strata. While filtering through the eapth, it is generally cleansed of all the organic substances whose decay would inevitiibly taint its purity, and comes forth AQUEDUCTS. 41 salubrious and refreshing, a source of health and enjoyment to the whole animal creation. The extreme limits to which the waters descend into the earth of course escape our direct observation, as the lowest point to which the subterranean regions have been probed is less than 2,000 or 2,600 feet below the level of the sea ; but as we know from the formation of many basins that the strata of which they are composed attain in many cases a thickness of from 20,000 to 30,000 feet, there can hardly be a doubt that they are permeated by water to an equal depth. As steam plays so great a part in volcanic phenomena, the seat or effective cause of which must needs be sought for at an immense distance below the surface of the earth, we have another proof of the vast depth to which the subterranean migrations of water are able to attain. After this brief glimpse into the reservoirs of the deep, we have to ascertain the power which raises their liquid contents and forces them to reappear upon the surface of the earth. If we pour water into a tube, bent in the form of the letter tr, it will rise to an equal level in both branches. We wiU now suppose that the left branch of the tube opens at the top into a vast reservoir, which is able to keep it constantly filled, and that the right branch is cut off near the bottom, so that only a small vertical piece remains. The pressure of the water column in the left branch will in this case force the liquid to gush out of the orifice of the shortened right branch to the level which it occupied while the branch was still entire. These two hydrostatic laws, or rather these two modifica- tions of the same law, have been frequently put to practical uses, as, for instance, in the communicating tubes which dis- tribute the waters of an elevated source or reservoir to the various districts of a town, or in the subterranean conduits which serve to create fountains, such as those of Versailles or the Crystal Palace. When the Romans intended to lead water from one hUl to another, they constructed, at a vast expense, magnificent aque- ducts across the intermediate valley ; but the Turks, whom we look upon as ignorant barbarians, obtain the same result in a much more economical manner, and in this respect far 4-2 THE SUBTERRANEAN WORLD. surpass the ancients, wlio, had they been better acquainted with the first principles of hydrostatics, would indeed have left us fewer specimens of their architectural skill, but would at the same time have saved themselves a great deal of un- necessary expense. Down the slope of the hill from which the water is to be conducted, the Turks lay a tube of brick or metal, which, crossing the valley, moulds itself to its different inflections, and ultimatel}' ascends the declivity of the hill on the opposite side, where, in virtue of the law above cited, the water rises as high as on that from which it descended. If we suppose the descending branch of the tube to be pro- longed only as far as the level of the valley, with a superficial orifice, then the liquid will of course gush forth in a vertical column, and form a jet d'eau, or fountain, its height being determined by the elevation of the sheet of water by which it is fed, and the consequent degree of pressure which acts upon it. This is the principle on which all artificial foun- tains are constructed. The conduit, for instance, which feeds the grand fountain of the Tuileries receives its water from a reservoir situated on the heights of Chaillot. Whatever the form of the tube may be in which the liquid is contained, the simple hydrostatic law which regulates its level remains unmodified. Let the tube be circular, elliptic, or square, with a single orifice or with many — let it be open or choked with pebbles or permeable sand — in every case the water will invariably rise to the same height, provided the tube be perfectly water-tight ; or else gush forth wherever it finds an opening below the highest level. This hydrostatic principle so perfectly illustrates the origin of springs, that it is almost superfluous to enter into any further details on the subject. When we consider that porous or absorbent strata, alter- nating with impermeable strata, frequently crop out on the back or on the slope of hiUs or mountains, and then, having reached their base, extend horizontally beneath the plain, there can be no doubt that they are placed in the same hydrostatic conditions as ordinary water-conducting tubes, and that wherever any fissure or opening occurs in the superincumbent impervious strata at any point below HOT AND COLD SPRINGS. 43 tlie highest level of the water, springs must necessarily be formed. As the same strata often extend over many hiindreds of miles, we cannot wonder that sources frequently issue from the centre of immense plains, for the hydrostatic pressure which causes them to gush forth may have its seat at a very considerable distance. As the waters by which the springs are fed have often vast subterranean journeys to perform, their temperature is natu- rally independent of that of the seasons or of the changes of the atmosphere. Thus, cold springs occur in a tropical climate, when their subterranean channels descend from high mountains, and boiling sources gush forth in the Arctic regions when forced upwards from a considerable depth. While the waters filter through the earth, they also naturally dissolve a variety of substances, and hence all springs are more or less impregnated with extraneous particles. But many of them, particularly such as are of a higher temperature, contain either a larger quantity or so peculiar a combination of mineral substances as to acquire medicinal virtues of the highest order. The geological phenomena which favour the production of thermal springs are extremely interesting, and point to a deep-seated origin. By far the greater number of these fountains arise near the scene of some great subterranean disturbance, either connected with volcanic action, or with the elevation of a chain of mountains, or lastly by cliffs and fissures caused by disruption. Thus the thermal springs of Matlock and Bath accompany great natural fissures in the mountain limestone, and the hot springs of Wiesbaden and Ems, of Carlsbad and Toeplitz, all lie contiguous to remarkable dislocations, or to great lines of elevation, or to the neighbour- hood of a volcanic focus. One of the most remarkable phenomena of thermal springs is the constant invariableness of their temperature and their mineral impregnation. During the last fifty or sixty years, ever since accurate thermometrical observations and chemical analyses have been made, the most celebrated mineral sources of Germany have been found to contain the same proportion of mineral substances. This is truly astonishing 44 THE SUBTERRANEAN WORLD. when we consider that the latter are merely dissolved by the waters while passing through the bowels of the earth, and that a considerable number of them are frequently found together in the same source. Another remarkable fact is, that, even in countries exposed to violent and frequent earthquakes, so many subterranean watercourses have remained unaltered for 2,000 years at least. The sources of Greece still flow apparently as in the times of Hellenic antiquity. The spring of Erasinos, two leagues south of Argos, on the declivity of the Chaonian mountains, is mentioned by Herodotus. At Delphi the Cassotis (now "Wells of Saint Nicholas) still flow under the ruins of the temple of Apollo, and the hot baths of Aidepsos stiU exist in which Sylla bathed during the Mithridatic war. Many springs exhibit the singular phenomenon of an intermittence which is independent of the quantity of rain falling in the district, or of the flux and reflux of the tide in a neighbouring river. In many cases the simple and well- known hydrostatical law exemplified in the common siphon* affords a very ready and sufB.cient explanation of the phe- nomenon. In the annexed diagram the vessel a communicates, by a tube c, with the siphon tube b, and it is manifest that when the water in a rises above the level of the top of h, ib * A siphon, as is well known, is a bent tube, Ila^•ing one leg longer than the other. When this tube is filled with any liquid, and the shorter end is immersed in a vessel conta,ining liquid of the same kind, the weight of the column in the longer leg will cause the liquid to begin to run out, and it will continue running till the vessel is emptied. This arises from the pressure of air on the exposed surface of fluid, forcing it up through the tube to prevent vacuum, which would otherwise be formed at the highest point; and the extreme limit of length at which the siphon will act is therefore determined by the height of a column of the fluid equal to the pressure of the atmosphere (fifteen pounds on the square inch). The limit in the case of water is something more than thirty feet. IKTEEMITTENT SPRINGS. 45 will beg-in to flow over and escape, as at d. But as soon as this is the case the tube b begins to act as a siphon, and draws oft' all the water in a, so that if a constant supply is poured into a, but at a rate slower than the rate of the dis- charge at (/, there will be an intermittent discharge, the interval depending on the relation of the rate of filling to that of emptying. The case of a subterranean cavity in a limestone rock, slowly fed by drainage from the cracks and fissures of the rock above, and communicating at a distant point with the surface by a bent or siphon tube, is evidently strictly ana- logous. SECTION OF AN INTERMITTENT STRING' Iceland, pre-eminently the land of volcanic wojiders, pos- sesses in the Great Geysir the most remarkable intermittent fountain in the world. 'At the foot of the Laugarfjall hill, in a green plain, through which several rivers meander like threads of silver, and where chains of dark-coloured moun- tains, overtopped here and there by distant snow-peaks, form a grand but melancholy picture, dense volumes of steam indicate from afar the site of a whole system of thermal springs congregated on a small piece of ground not exceeding- twelve acres in extent. In any other spot the smallest of these boiling fountains would arrest the traveller's attention, but here his whole mind is absorbed by the Great Geysir. In the course of countless ages, this monarch of springs has formed out of the silica which it deposits a mound which rises to about thirty feet above the general surface of the 46 THE SUBTEKEANEAN -^YORLD. plain, and slopes on all sides, to the distance of a Imndred feet or thereabouts, from the border of a large circular basin situated in its centre, and measuring about fifty-six feet in the greatest diameter and fifty-two feet in the narrowest. In the middle of this basin, forming as it were a gigantic GEYSiltS OF ICELAND. funnel, there is a pi^^e or tube, which at its opening in the basin is eighteen or sixteen feet in diameter, but narrows considerably at a little distance from the mouth, and then appears to be not more than ten or twelve feet in diameter. It has been probed to a depth of seventy feet, but it is more than probable that hidden channels ramify further into the bowels of the earth. The sides of the tube are smoothly polished, and so hard that it is not jjossible to strike oif a piece of it with a hammer. Generally the whole basin is found filled up to the brim with sea-green water as pure as crystal, and of a temperature of from 180° to 190". Astonished at the placid tranquillity of the pool, the traveller can hardly believe that he is really standing on the brink of the far-famed Geysir; but suddenly a subterranean thunder is heard, the ground trembles luider his feet, the water in the basin begins to simmer, and large bubbles of steam rise from tlie tube and burst on reaching the surface, throwing lip small jets of spray to the height of several feet. Every THE GEYSIKS OF ICELAND. 47 instant he expects to witness the grand spectacle which has chiefly induced him to visit this northern land ; but soon the basin becomes tranquil as before, and the dense vapours produced by the ebullition are wafted away by the breeze. These smaller eruptions are regularly repeated every eighty or ninety minutes, but frequently the traveller is obliged to wait a whole day or even longer before he sees the whole power of the Geysir. A detonation louder than usual pre- cedes one of these grand eruptions ; the water in the basin is violently agitated ; the tube boils vehemently ; and sud- denly a magnificent column of water, clothed in vapour of a dazzling whiteness, shoots up into the air with immense impetuosity, to the height of eighty or ninety feet, and, radi- ating at its apex, showers water and steam in every direction. A second eruption and a third rapidly follow, and after a few minutes the fairy spectacle has passed away like a fan- tastic vision. The basin is now completely dried up, and on looking down into the shaft, the traveller is astonished to see the water about six feet frotn the rim, and as tranquil as in an ordinary well. After about thirty or forty minutes it again begins to rise, and after a few hours reaches the brim of the basin. Soon the subterranean thunder, the shaking of the ground, the simmering above the tube begin again — a new gigantic explosion takes place, to be followed by a new period of rest — and thus this wonderful play of nature goes on, day after day, year after year, and century after century. The mound of the Geysir bears witness to its immense antiquity, as its water contains but a minute portion of silica.' * The explanation of these wonderful phenomena has exer- cised the ingenuity of many natural philosophers ; but Pro- fessor Bunsen's theory seems the most plausible. Having first ascertained, by experiment, that the water at the mouth of the tube has a temperature, corresponding to the pressure of the atmosphere, of about 212° F., he found it much hotter at a certain depth below ; a thermometer, suspended by a string in the pipe, rising to 266° F., or no less than 48° above the boiling point. By letting down stones, suspended by strings, to various depths, he next came to the conclusion » ' The Polar World,' p. 54. 48 THE SUBTERRANEAN WORLD. that the tube itself is the main seat or focus of the mecha- nical power which forces the huge water column upwards. For the stones which were sunk to greater distances from the surface were not cast up again when the next eruption of the Geysir took place, whereas those nearer the mouth of the tube were ejected to a considerable height by the ascending water-column. Other experiments also were made, tending to demonstrate the singular fact that there is often scarcely any motion below when a violent rush of steam and water is taking place above. It seems that when a lofty column of water possesses a temperature increasing with the depth, any slight ebullition, or disturbance of equilibrium, in the upper portion may first force up water into the basin, and then cause it to flow over the edge. A lower portion, thus suddenly relieved of part of its pressure, expands, and is converted into vapour more rapidly than the first, owing to its greater heat. This allows the next subjacent stratum, which is much hotter, to rise and flash into a gaseous form ; and this process goes on till the ebullition has descended from the middle to near the bottom of the funnel.* In many geological basins, the deep subterranean waters are frequently inclosed over a surface of many square miles between impermeable beds of clay or hard rock, which no- where permit them to escape ; but if a hole be bored deep enough to reach a permeable bed, it is evident that they will then gush forth more or less violently, according to the degree of hydrostatic pressure which acts upon them. This is the simple theory of the Artesian WeUs, so caUed from the French province of Artois, where, as far back as the beginning of the twelfth century, springs of water were arti- ficially obtained by perforating the soil to a certain depth in places where no indication of springs existed at the surface. The barbarous inhabitants of the Sahara seem, however, to have long preceded the Artesians in the art of sinking deep wells, for Olympiodorus, a writer who flourished at Alexan- dria about the middle of the sixth century, mentions pits sunk in the oasis to the depth of 200 or 300 yards, and pouring forth streams of water, used for irrigation. * Liebig's 'Annalen,' translated in 'Reports and Memoirs of the Cavendish Society,' London, 1848, p. 351. tup: well op grexelle. 49 By tlio aid of geological science, and of greater mechanical skill, Artesian borings* are at present frequently undertaken m civilised countries, Avlierever the nature of the grouud promises success, and the want of water is sufficiently great to warrant the attempt. Sometimes the water is reached at a moderate distance from the surface, but not seldom it has been found necessary to bore to a depth of '200 or 300 fathoms. Often efforts, even on this large scale, have proved vain, and the ^vork has been abandoned in despair. One of the most remarkable instances on record of a suc- cessful sinking for water is that of the Artesian well of Greuelle, one of the Parisian suburbs. POHOUS STRATA. AK'I'i>IA.\ WklX ^L^^■K LN THE LOXDON HASIN. The work was begun with an auger of about a focit in dia- meter, and the borings showed successiveljr the alluvial soil and subsoil, and the tertiary sands, gravels, clays, lignite, &c., until the chalk was reached. The work was then carried on regularly through the hard upper chalk down to the lower chalk with green grains, the dimension of the auger being reduced at 500 feet to a nine-inch, and at 1,300 feet to a six-inch aperture. When the calculated depth of 1,500 feet had been reached, and as yet no result appeared, the Govern- ment began to be disheartened. Still, upon the urgent repre- sentations of the celebrated Arago, the sinking was continued, until at length, at the depth of 1,800 feet, the auger, after a *• Sre Chapter on Mines in (Toneral. for a short mronnt of oavlli-lioi-iiin' opera- tions. E 50 THE SUBTERRANEAN WORLD. violent shock whieli made the ground tremble, suddenly turned without an effort. ' Either the auger is broken, or we have gained our end,' exclaimed the director of the work; and a few moments after, a large column of water gushed out of the orifice. It took more than seven years to accom- plish this grand work (1833-41), which was retarded by numberless difficulties and accidents. About half-a-million gallons of perfectly limpid water of a temperature of 82° Fahr. are daily supplied by the Puits de Grenelle, and amply repay its cost (862,432 fr. 66 centimes =14,500L). The high temperature of Artesian springs, when rising from considerable depths, has been turned to various prac- tical uses. Thus, near Canstadt, in Wurtemberg, several mills are kept in work, during the severest cold of winter, by means of the warm water of Artesian wells which has been turned into the mill-ponds, and at Heilbronn several proprietors save the expense of fuel by leading Artesian water in pipes through their green-houses. In some localities the pure and constantly temperate Artesian waters are made use of for the cultivation of cress. The vigorous growth of this salutary herb in the beds of tivulets, where natural springs gush forth, gave the idea of this applica- tion, which is so profitable that the cress nurseries of Erfurt yield a produce of 12,000Z. a year. Fish ponds have also been improved by such warm springs being passed through them. Among the localities benefited by the boring of Artesian wells, Venice deserves to be particularly noticed. For- merly the City of the Doges had no other supply of water but that which was conveyed by boats from the Brenta, or obtained from the rain collected in cisterns. Hence the joy of the inhabitants maybe imagined, when, in 1846, an Arte- sian boring in the Piazza San Paolo began to disgorge its water at the rate of forty gallons per minute, and when other undertakings of the same kind proved equally successful. Wherever a well gushes forth in the Sahara, it brings life into the wilderness ; the date-tree flourishes as far as its fertilising waters extend, and the wandering Arab changes into a sedentary cultivator of the soil. Thus the boring of Artesian wells on the desert confines of South Algeria has AKTESIAN WELLS IN ALGERIA. 51 been tlie means of wonderful improvement, and if the French, have too often marked their dominion in Africa by a barbarous oppression of the Arabs, they, in this respect at least, appear in the more amiable light of public benefactors. A boring apparatus was first landed at PhilippeviUe in April 1856, and conveyed with immense difficulty to the Oasis Wad Eir at Tamerna. The work was begun in May, and on the 19th of June, a spring, to which the grateful inhabitants gave the name of the ' Well of Peace,' gushed forth. Soon after another source was tapped at Tamelhat, in the Oasis Temacen, and received the name of the 'Well of God's blessing.' The beneficent instrument of abundance was now con- veyed to the Oasis Sidi Rasched, fifteen miles beyond Tuggurt. Here the auger had scarcely reached a depth of 120 feet when a perfect stream gushed forth, which, according to the praiseworthy Arab custom, received the name of the ' Well of Thanks.' The opening of this wonderful source gave rise to many touching scenes. The Arabs came in throngs to witness the joyful spectacle : each of them poured some of the water over his head, and the mothers bathed their children in the gushing flood. An old scheik, unable to conceal his emotion, fell down upon his knees, and shedding tears of joy, fervently thanked God for having allowed him to witness such a day. The next triumph was the boring of four wells in the desert of Morran, where previously no spring had existed. In the full expectation of success, everything had been pre- pared to turn this new source of wealth to immediate use, and part of a nomadic tribe instantly settled on the spot, and planted 1,200 date-trees. A dreary solitude was changed, as if by magic, into a scene of busy life. These few examples suffice to show the vast services which Artesian wells are destined at some future time to render to many of the arid regions of Africa. Both in the Sahara and in the basin-shaped deserts, which extend, under various names, froTn the Cape Colony to the neighbourhood of Lake Ngami, there are, beyond all doubt, numberless spots where water, the fertilising element, may be extracted from the bowels of the earth. u 2 52 THE SUBTERRANEAN WORLD. In tlie droughty plains of Australia also a vast sphere of utUity is reserTed to the Artesian wells. Here, also, they will subdue the desert, unite one coast to another by creating stations in the wilderness, and, with every new source which they call to life, promote both material progress and intel- lectual improvement. 53 CHAPTEE VI. VOLCANOES. Volcanic Mountains — Extinct and Active Craters — Their Size — Dangerous Crater- explorations — l)r. Judd in the Kilauea Pit — Extinct Craters — Their Beauty — The Crater of Mount Vultur in Apulia — Volcanoes still constantly forming — Jorullo and Isalco — Suhmarine Volcanoes — Sabrina and Graham's Island — ■ Santorin — Number of Volcanoes — Their Distribution— Volcanoes in a constant state of eruption — Stromboli — Fumaroles — The Lava Lakes in Kilauea — Vol- canic Paroxysms — Column of Smoke and Ashes — Detonations — Explosion of Cones — Disastrous Effects of Showers of Ashes and Lapilli — Mud Streams — Fish disgorged from Volcanic Caverns — Eruption of Lava — Parasitic Cones — Phenomena attending the Flow of a Lava Stream — Baron Papalardo — Meeting of Lava and Water — Scoriae — Lava and Ice — Vast Dimensions of several Lava Streams — Scenes of Desolation — Volcanoes considered as safety-valves — Probable Causes of Volcanoes. VOLCANOES are vents whicli either have comnmnicated, or still communicate, by one or several cMmney-like canals or shafts, with a focus of subterranean fire, emitting, or having once emitted, heated matter in a soUd, semi-liquid, or gaseous state. The first eruption of a volcano neces- sarily leaves a mound of scoriae and lava, while numerous eruptions at length raise mountains, which are frequently of an amazing extent and height. These mountains, which are generally called volcanoes, though in reality they are but an effect of volcanic action situated far beneath their base, are called extinct when for many centuries they have exhibited no signs of combustion — active, when, either perpetually or from time to time, eruptions or exhalations of lava, scoriae, or gases take place from their summits, or from vents in their sides. Their shape is generally that of a more or less truncated cone ; but whUe some, like Cotopaxi or the Peak of Teneriffe, rise with abrupt declivities in the shape of a sugar-loaf, others, like Mauna Loa in the island of 54 THE SUBTERRANEAN WORLD. Hawaii, gradually, and almost imperceptibly, ascend from a vast base embracing many miles in circuit. Their beigbts also vary greatly. While some, .like Madana in Santa Cruz, or Djebel Teir on the coast of the Eed Sea, scarcely raise their summits a few hundred feet above the level of the ocean, others, like Chuquibamba (21,000 feet), or Aconcagua (22,434 feet), hold a conspicuous rank among mountains of the first class. The summit of a volcano generally terminates in a central cavity or crater, where the eruptive channel finds its vent. Craters are sometimes regularly funnel-shaped, descending with slanting sides to the eruptive mouth, but more com- monly they are surrounded with high precipitous rock-walls, while their bottom forms a plain, which is frequently com- pletely horizontal, and sometimes of a considerable extent. Its surface is rough and uneven, from the mounds of volcanic sand, of scorise, or of hardened lava with which it is covered, and generally exhibits a scene of dreadful desolation, rendered still more impressive by the steam and smoke, which, as long as the volcano continues in an active state, issue from its crevices. Within this plain, the eruptive orifice or mouth of the volcano is almost universally surrounded by an elevation, composed of ejected fragments of scorise thrown from the vent. Such cones are forming constantly at Vesuvius, one being no sooner destroyed by any great eruption, before another begins to take shape and is enlarged, till often it reaches a height of several hundred feet. Thus the crater of an active volcano is the scene of per- petual change — of a continual construction and re-construc- tion, and the sands of the sea do not afford a more striking image of inconstancy. The various craters are of very different dimensions. While the chief crater of Stromboli has a diameter of only fifty feet, that of Gunong Tenger, in Java, measures four miles from end to end ; and, though the depth of a crater rarely exceeds 1,000 or 1,500 feet, the spectator, standing on the brink of the great crater of Popocatepetl, looks down into a gulf of 8,000 feet. From the colossal dimensions of the larger craters, it may VOLCANIC CRATERS. 55 well be imagined that tlieir aspect exhibits some of the sub- limest though most gloomy scenery in nature — the picture of old Chaos with all its horrors. The volcano Gunong Tjerimai, in Java, which rises to the height of 9,000 feet, is covered with a dense vegetation up to the crater's brink. On emerging from the thicket, the wanderer suddenly stands on the verge of an immense exca- vation encircled with naked rocks. He is obliged to hold himself by the branches of trees, or to stretch himself flat upon the ground, so as to be able to look down into the yawning gulf. The deep and inaccessible bottom of the crater loses itself in misty obscurity, and glimmers indis- tinctly through the vapours which are there slowly and incessantly ascending from its mysterious depths. All is •desolate and silent, save when a solitary falcon, hovering over the vast chasm, awakes with her discordant screech the echoes of the precipice. Through a telescope may be seen, in various parts of the huge crater walls, swarms of small swal- lows, which have there built their nests, flying backwards and forwards. The eye can detect no other signs of life, the ear distinguish no other sound. Humboldt describes the view down the crater of the Eucu- Pichincha — a volcano which towers above the town of Quito to a height of 15,000 feet — as the grandest he ever beheld during all his long wanderings. Guided by an Indian, he ascended the mountain in 1802, and after scaling, with great difiiculty and no small danger, its steep and rocky sides, he at length looked down upon the black and dismal abyss, whence clouds of sulphurous vapour were rising as from the gates of hell. The descent into the crater of an active volcano is at all times a difiicult and hazardous enterprise, both from the steepness of its encircling rock walls, and the sufibcating vapours rising from its bottom ; but it is rare indeed that a traveller has either the temerity or the good fortune to pene- trate as far as the very mouth of the eruptive channel, and to gain a glimpse of its mysterious horrors. When M. Houel visited Mount Etna in 1769, he ventured to scale the cone of stones and ashes which had been thrown up in the centre of the crater, where thirty years before there was only a prodigious chasm or gulf. On ascending this mound, which 56 THE SUBTERRANEAN WORLD. emitted smoke from every pore, the adventurous traveller- sunk about mid-leg at every step, and was in constant terror of being swallowed up. At last, wben the summit was reached, the looseness of the soil obliged him to throw him- self down flat upon the ground, that so he might be in less danger of sinking, while at the same time the sulphurous exhalations arising from the funnel-shaped cavity threatened suffocation, and so irritated his lungs as to produce a very troublesome and incessant cough. In this posture the traveller viewed the wide unfathomable gulf in the middle of the crater, but could discover nothing except a cloud of smoke, which issued from a number of small apertures scattered all around. Prom time to time dreadful sounds issued from the bowels of the volcano, as if the roar of artillery were re- bellowed throughout all the hollows of the mountain. They were no doubt occasioned by the explosions of pent-up gases striking against the sides of these immense caverns, and mul- tiplied by their echoes in an extraordinary manner. After the iirst unavoidable impression of terror had been overcome, nothing could be more sublime than these awful sounds, which seemed like a warning of Etna not to pry too deeply into his secrets. Dr. Judd, an American naturalist, who, in 1841, descended into the crater of Kilauea, on Mauna Loa, in Hawaii, weU- nigh fell a victim to his curiosity. At that time, the smallest of the two lava pools which boil at the bottom of that extra- ordinary pit appeared almost inactive, giving out only vapours, with an occasional jet of lava at its centre. Dr. Judd, con- sidering the quiet favourable for dipping up some of the liquid with an iron ladle, descended for the purpose to a narrow ledge bordering the pool. While he was preparing to carry out his plans, his attention was excited by a sudden sinking of its surface ; the next instant it began to rise, and then followed an explosion, throwing the lava higher than his head. He had scarcely escaped from his dangerous situation, the moment after, by the aid of a native, before the lava boiled up, covered the place where he stood, and, flowing out over the northern side, extended in a stream a mile wide to a distance of more than a mile and a half ! In extinct volcanoes, the picture of desolation originally EXTINCT VOLCANOES. 57 shown bjr tlieir craters lias not seldom been clianged into one of c'liuTuiing loveliness. Tall forest trees cover the bottom of the Tofua crater in Upolu, one of the Samoau group ; and in the same island, a circular lake of crystal pnrity, belted with a girdle of the richest green, has formed in the depth of the Lanuto crater. The lakes of Averno near Naples, and of Bolsena, Bracciano, and Eoncigiione, likewise fill the hollows of extinct craters, constituting scenes of surpassing beauty, rendered still more impressive by the remembrance of the stormy past which pre- ceded their present epoch of tranquillity and peace. Mr. MaJlet describes, with glowing colours, the singular beauty of EX'II2;CT CRATE]! OF HALEAKAL,^, the forest scenery around the two extinct craters of Mount Vultur in Apulia, which time has converted into two deep» circular lakes. ' I descend amongst aged trunks and overarching limbs, and pass over masses of rounded lava-blocks and cemented lapilli. All is quietude ; the soft breeze of a quiet winter's afternoon fans across the embosomed water, from the early wheat-fields and the furrowed acres of the opposite steep slopes, and brings the gentle ripple lapping amongst the roots of the old hazels at my feet. ' Off before me, and to my left, crowning the slope, are the grey ruins of some ancient church or castle, and far above me to the rij^-ht, nestled against the lava crags, behind and 58 THE SUBTERRANEAN WORLD. above it, standing out white and clear, I see the strong but- tressed mass of the monastery of St. Michael. How hard it is to realise that this noble and lovely scene, full of every leafy beauty, was once the innermost bowl of a volcano ; that every stone around me, now glorious in colour with moss and lichen, sedum and geranium, was once a glowing mass, vomited from out that fiery and undiscovered abyss, which these placid wa.ters now bury in their secret cliambers.' The line of demarcation between active and extinct vol- canoes is not easily drawn, as eruptions have sometimes taken place after such long intervals of repose as to warrant the belief that the vents from which they issued had long since been completely obliterated. Thus, though nearly six centuries have passed since the last eruption of Epomeo in the island of Ischia, we are not entitled to suppose it extinct, since nearly seventeen centuries elapsed between this last explosion and the one which preceded it. Since the begin- ning of the fourteenth century Vesuvius also enjoyed a long rest of nearly three hundred years. During this time the crater got covered with grass and shrubs, oak and chestnut trees grew around it, and some warm pools of water alone reminded the visitor of the former condition of the mountain, when, suddenly, in December 1631, it resumed its ancient activity, and seven streams of lava at once burst forth from its subterranean furnaces. While, in many volcanic districts, such as that of the Eifel on the left bank of the Ehine, and of Auvergne, in Central France, the once active subterranean fires have long since been extinguished, and no eruption of lava has been recorded during the whole period of the historic ages, new volcanoes, situated at a considerable distance from all previously active vents, have arisen from the bowels of the earth, almost within the memory of living man. From the era of the discovery of the New World to the middle of the last century, the country between the mountains Toluca and Colima, in Mexico, had remained undisturbed, and the space, now the site of JoruUo, which is one hundred miles distant from each of the above- mentioned volcanoes, was occupied by fertile fields of sugar- cane and indigo, and watered by two brooks. In the month of June 1759, hollow sounds of an alarming nature were SUBAQUEOUS VOLCANOES. 59 heard, aad earthquakes succeeded eacli other for two months, until, at the end of September, flames issued from the ground, and fragments of burning rocks were thrown to prodigious heights. Six volcanic cones, composed of scorise and frag- mentary lava, were formed on the line of a chasm, which ran in the direction of N.E. to S.W. The least of the cones was 300 feet in height, and JoruUo, the central volcano, was elevated 1,600 feet above the level of the plain. The ground where now, in Central America, Isalco towers in proud eminence, was formerly the seat of an estancia or cattle- estate. Towards the end of the year 1769, the inhabitants were frequently disturbed by subterranean rumblings and shocks, which constantly increased in violence, until on Tebruary 23, 1770, the earth opened, and pouring out quantities of lava, ashes, and cinders gave birth to a new volcanic mountain. Besides those volcanic vents which are situated on the dry land, there are others which, hidden beneath the surface of the sea, reveal their existence by subaqueous eruptions. Columns of fire and smoke are seen to rise from the dis- coloured and agitated waters, and sometimes new islands are gradually piled up by the masses of scorisB and ashes ejected from the mouth of the submarine volcano. In this manner the island of Sabrina rose from the bottom of the sea, near St. Michael's in the Azores, in the year 1811 ; and still more recently, in 1831, Graham's Island was formed in the Mediterranean, between the coast of Sicily and that project- ing part of the African coast where ancient Carthage stood. Slight earthquake shocks preceded its appearance, then a column of water like a water-spout, 60 feet high and 800 yards in circumference, rose from the sea, and soon afterwards dense volum.es of steam, which ascended to the height of 1,800 feet. Then a small island, a few feet high with a crater in its centre, ejecting volcanic matter, and immense columns of vapour, emerged from the agitated waters, and in a fortnight swelled to the ample proportions of a height of 200 feet, and a circumference of three miles. But both Sabrina and Graham's Island, being built of loose scorise, were soon cor- roded by the waves, and their last traces have long since disappeared under the surface of the ocean. 60 THE SUBTERRANEAN WORLD. Near Pondiclierry, in India ; near Iceland, in the Atlantic Ocean ; half a degree to the south of the equator in the pro- longation of a line drawn from St. Helena to Ascension; near Juan Fernandez, &c., similar phenomena have occurred within the last hundred years, but, probably, nowhere on a grander scale than in the Aleutian Archipelago, where, about thirty miles to the north of Unalaska, near the isle of Umnack, a new island, now several thousand feet high and two or three miles in circumference, was formed in 1796. The whole bottom of the sea between this new creation of the volcanic powers and Umnack has been raised by the eruptive throes which gave it birth ; and where Cook freely sailed in 1778, numberless cliffs and reefs now obstruct the passage of the mariner. The famous subaqueous volcano which, in the year 186 before the Christian era, began its series of historically recorded eruptions, by raising the islet of Hiera (the ' Sacred ') in the centre of the Bay of Santorin, opened two pew vents in 1866. Amid a tremendous roar of steam and the shooting up of prodigious masses of rock and ashes, two islets were formed, which ultimately rose to the height of 60 and 200 feet. The eruption continued for many months, to the delight and wonder of the numerous geologists who came from all sides to witness the extraordinary spectacle. Thus, in many parts of the ocean, we see the submarine vol- canic fires laying the foundations of new islands and archi- pelagos, which, after repeated eruptions following each other in the course of ages, will probably, like Iceland, extend over a considerable space and become the seats of civilised man. As a very considerable part of the globe has never yet been scientifically explored, it is, of course, impossible to determine the exact number of the extinct and active vol- canoes which are scattered over its surface. Werner gives a list of 193 volcanoes, and Humboldt mentions 407, of which 225 are still in a state of activity. The newest computation of Dr. Fuchs, of Heidelberg,* increases the number to a total of 672, of which 270 are active. Future geographical dis- coveries will, no doubt, make further additions to the list, and show that at least through a thousand different vents * ' Die Tulcanisclien Erscheimingeu der Erde.' Liepzig, 1865. VOLCANIC RANGES. 61 tlie subterranean fires have, at various periods of tlie earth's history, piled up their cones of scoriae and lava. The volcanoes are very unequally distributed over the sur- face of the globe, for, while in some parts they are thickly clustered together in groups or rows, we find in other parts vast areas of land without the least sign of volcanic action. An almost uninterrupted range of volcanoes extends in a sinuous line from the Gulf of Bengal, through the East Indian Archipelago, the Moluccas, the Philippines, Formosa, Japan, and the KurUes, to Kamtschatka. This desolate peninsula is particularly remarkable for the energy of its subterranean fires, as Ermann mentions no less than twenty- one active volcanoes, ranged in two parallel lines through- out its whole length, and separated from each other by a central range of mountains, containing a large and un- known number of extinct craters. In Java, where more than thirty volcanoes are more or less active, the furnaces of the subten-anean world are still more concentrated and dreadful. The immense mountain-chains which run parallel to the western coasts of America are likewise crowned with nume- rous volcanic peaks. Chili alone has fourteen active vol- canoes, Bolivia and Peru three, Quito eleven. In Central America we find twenty-one volcanoes, which are chiefly grouped near the Lake of Nicaragua, and to the west of the town of Guatemala. The peninsula of Aljaska, and the chain of the Aleiites, possess no less than thirty- six volcanos, scattered over a line about 700 miles long; and thus we find the eastern, western, and northern boundaries of the Pacific encircled wiib a girdle of volcanic vents, while the subterranean fire^ have left the western shores of the Atlantic com- paratively undisturbed. With 4:he exception of Iceland, which is famous for the widely devastating eruptions of its burning mountains, the volcanic energies of Europe are at present limited to the submarine craterof Santorin, and to the small area of Etna, Vesuvius, and the Lipari Islands. But, situated in the centre of the ancient seats of civilisation, and for so many centuries the object of the naturalist's researches, of the 62 THE SUBTERRANEAN WORLD. traveller's curiosity, and of tlie poet's song, they surpass in renown all other volcanic regions in the world. Most other volcanoes vent their fury over lands either so wild or so remote that the history of their eruptions almost sounds like a legend from another planet ; but thousands of us have visited Etna and Vesuvius, and the explosion of their rage menaces towns and countries which classical remembrances have almost invested with the interest of home. Some volcanoes are in a continual state of eruption. Isalco, born, as we have seen, in 1770, has remained ever since so active as to deserve the name of the Faro (lighthouse) of San Salvador. Its explosions occur regularly, at intervals of from ten to twenty minutes, and throw up a dense smoke and clouds of ashes and stones. These, as they fall, add to the height and bulk of the cone, which is now about 2,500 feet high. For more than two thousand years, the fires of Stromboli have never been extinct, nor has it ever failed to be a beacon to the mariner while sailing after nightfall through the Tyrrhenian Sea. Mr. Poulett Scrope, who visited Stromboli in 1820, and looked down from the edge of the crater into the mouth of the Volcano, some 300 feet beneath him, found the phenomena precisely such as Spallan- zani described them in 1788. ' Two rude openings show themselves am.ong the black chaotic rocks of scoriform lava which form the floor of the crater. One, is to appearance, empty, but from it there proceeds, at intervals of a few minutes, a rush of vapour, with a roaring sound, like that of a smelting furnace when the door is opened, but infinitely louder. It lasts about a minute. Within the other aper- ture, which is perhaps twenty feet in diameter, and but a fe'vy yards distant, may be distinctly perceived a body of mol^n matter, having a vivid glow even by day, approaching to that of white heat, which rises and falls at intervals of from ten to fifteen minutes. Each time that it reaches in its rise the lip of the orifice, it opens at the centre, tike a great bubble bursting, and discharges upwa.rds an explosive volume of dense vapour, with a shower of fragBients of incandescent lava and ragged scoriae, which rise to a height of several hundred feet above the lip of the crater.' The volcanoes of Masaya, near the lake of the same name THE VOLCANO OF MAUNA LOA. G3 in Nicaragua ; of Sioa, in the Moluccas ; and of Tofua, in the Friendly Islands, are also, like Stromboli, in a state of per- manent eruption. But far more commonly the volcanoes burst forth only from time to time in violent paroxysms, separated from each other by longer phases of moderate activity, during which their phenomena are confined to the exhalation of vapours and gases, sometimes also to the ejection of scorise or ashes ; to the oscillations of lava rising or subsiding in the shaft of the crater, to the gentle outflow of small sti'eains of lava from its eruptive cone, and to slight commotions of its border. A continual or periodical exhalation of steam and gases from the shaft of the crater or from chasms and fis- sures in its bottom, is the commonest phenomenon shown by an active volcano while in a state of tranquillity. Aqueous vapours compose the chief part of these exhalations, and along with other Volatile substances, such as sulphuretted hydrogen, sulphurous acid, muriatic acid, and carbonic acid, form the steam-jets or fumaroles, which escape with a hissing or roaring noise from all the crevices and chasms of the crater, and, uniting as they ascend in a single vapour- cloud, ultimately compose the lofty column of steam which forms so conspicuous a feature in the picturesque beauty of Etna or Vesuvius. High on the summit of Mauna Loa, where all vegetation has long since ceased, the warm steam of the fumaroles gives rise to a splendid growth of ferns in crevices sheltered from the wind ; and on the island of Pantellaria, the shepherds, by laying brushwood before the fumaroles, condense the steam, and thus procure a supply of water for their goats. The gentle fluctuations of lava in a crater while in a state of moderate activity are nowhere exhibited- on a grander Scale than in the pit of Kilauea on Mauna Loa. The mountain rises so gradually as almost to resemble a plain, and the crater appears like a vast gulf excavated in its flanks. The traveller perceives his approach to it by a few small clouds of steam, rising from fissures not far from his path. While gazing for a second indication, he stands unexpectedly upon the brink of the pit. A vast amphitheatre seven miles and a half in circuit has opened to view. Beneath a gray rocky precipice of 650 feet, a narrow plain 64 THE SUBTEERANEAN WOULD. of hardened lava extends, like a vast gallery, around the whole interior. "Within this gallery, below another similar precipice of 340 feet, lies the bottom, a vride plain of bare rock more than two miles in length. Here all is black monotonous desolation, excepting certain spots of a blood- red colour, which appear to be in constant yet gentle agitation. When Professor Dana visited Kilauea (December 1840), he was surprised at the stillness of the scene. The incessant motion in the blood-red pools was like that of a cauldron in constant ebullition. The lava in each boiled with such activity as to cause a rapid play of jets over its surface. One pool, the largest of the three then in action, was afterwards ascertained by survey to measure 1,600 feet in one diameter and 1,000 in another; and this whole area was boiling, as seemed from above, with nearly the mobility of water. Still all went on quietlj''. Not a whisper was heard from the fires below. White vapours rose in fleecy wreaths from the pools and numerous fissures, and above the large lake they collected into a broad canopy of clouds, not un- like the snowy heaps or cumuli that lie near the horizon on a clear day, though their fanciful shapes changed more rapidly. On descending afterwards to the black ledge or gallery at the verge of the lower pit, a half-smothered gurgling sound was all that could be heard from the pools of lava. Occasionally, there was a report like that of musketry, which died away, and left the same murmuring sound, the stifled mutterings of a boiling fluid. Such was the scene by day — awful, melancholy, dismal^ but at night it assumed a character of indescribable subli- mity. The large cauldron, in place of its bloody glare, now glowed with intense brilliancy, and the surface sparkled with shifting points of dazzling light, occasioned by the jets in constant play. The broad canopy of clouds above the pit, which seemed to rest on a column of wreaths and curling heaps of lighted vapour, and the amphitheatre of rocks around the lower depths, were brightly illuminated from the boiling lavas, while a lurid red tinged the distant parts of the inclosing walls and threw their cavernous recesses into deeper shades of darkness. Over this scene of restless flres PHENOMENA OF ERUPTION. 65 and fiery vapours, the heavens by contrast seemed unnatu- rally black, with only here and there a star, like a dim point of light. A paroxysmal eruption is generally announced by the intensification of the phenomena above described. Slight earthquakes are felt in the neighbourhood of the volcano, and follow each other in more rapid succession and vfith greater violence as the catastrophe draws near. A deep noise like the rolling of thunder, or like the roar of distant artillery, is heard under the ground ; the white steam from the crater ascends in denser clouds, which soon acquire a darker tinge ; and now the bottom of the crater suddenly bursts with a terrific crash, and with the rapidity of light- ning, an immense column of black smoke shoots up into the air, and, expanding at its upper end into a broad horizontal canopy, assumes a shape which has been compared with that of the Italian pine, the graceful tree of the South. As the column of smoke spreads over the sky, it obscures the light of the sun and changes day into night. Along with the smoke, showers of glowing lava are cast high up into the air, and, rising like rockets, either fall back into the crater or rattle down the declivity of the cone. At night the scene assumes a character of matchless grandeur, when the column of smoke — or, more properly speaking, of scoriae, vapour, and impalpable dust — is illu- minated by the vivid light of the lava glowing in the crater beneath. It then appears as an immense pillar of fire, rising with steady majesty in the midst of the uproar of all the elements, and ever and anon traversed by flashes of still greater brilliancy from the masses of liquid lava hurled forth by the volcano. The detonations which accompany an eruption are some- times heard as single crashes, at others as a rolling thunder or as a continuous roaring. They are frequently audible at an astonishing distance, over areas of many thousand square miles, and with such violence that they may be supposed to proceed from the immediate neighbourhood. Thus, during the eruption of Cosiguina in Nicaragua, which took place in the year 1834, the detonations were heard as loud as a thunderstorm in the neighbourhood of Kingston in Jamaica, r 66 THE SUBTEERANEAN WORLD. and even at Santa Fe de Bogota, whicli is a thousand miles distant from tlie volcano. Witli the increase of steam generated during an eruption, the quantity of ejected scoriae likewise increases in an astonishing manner, so that the volcano s mouth resembles ;i, constantly discharging mine of the most gigantic dimensions. The stones and ashes projected during a volcanic eruption vary considerably in size, from blocks twelve or fifteen feet in diameter to the finest dust. Both their immense quantity, and the force with which they are hurled into the air, show the utter insignificance of the strength displayed by the most formidable engines invented by man when compared with elementary power. Huge blocks are shot forth, as from the cannon's mouth, to a perpendicular elevation of 6,000 feet, and La Condamine relates that in 1533 Cotopasi hurled stones of eight feet in diameter in an oblique direction to the distance of seven miles. The lighter seorise, carried far away by the winds, not seldom bury whole provinces under a deluge of sand and ashes; and their disastrous effects, spreading over an immense area, are frequently greater than those of the lava-streams, whose destructive power is neces- sarily confined to a narrower space. To cite but a few exam- ples, the rain of sand and ashes which in 1812 menaced the Island of St. Vincent with the fate of Pompeii soon buried every trace of vegetation, and the affrighted planters and negroes fled to the town. But here also the black sand, along with many larger stones, fell rattling like hail upon the roofs of the houses, while at the same time a tremendous subterranean thunder increased the horrors of the scene. Even Barbadoes, though eighty miles from St. Vincent's, was covered with ashes. A black cloud, approaching from the sea, brought with it such pitchy darkness that in the rooms it was impossible to distinguish the windows, and a white pocket-handkerchief could not be seen at a distance of five inches. The fall of ashes caused in April 1815 by the eruption of the Temboro, in Sumbawa, not only devastated the greater part of the island, but extended in a westerly direction to Java, and to the north, as far as Celebes, with such an intensity that it became perfectly dark at noon. The roofs RESULTS OP SINGLE ERUPTIONS. 67 of houses at the distance of forty miles were broken in by the weight of the ashes that fell upon them. To the west of Sumatra the surface of the sea was covered two feet deep with a layer of floating pumice or scoriae, through which ships with difficulty forced their way. By the terrific eruption of Cosiguina in the Gulf of Fonseca, in Central America, in 1835, all the ground within a radius of twenty-five miles was loaded with scoriae and ashes to the depth of ten feet and upwards, while the lightest and finest ash was carried by the winds to places more than 700 miles distant. Bight leagues to the southward of the crater the ashes covered the ground to the depth of three yards and a half, destroying the woods and dwellings. Thousands of cattle perished, their bodies being in many instances one mass of scorched flesh. Deer and other wild animals sought the towns for protection; birds and beasts were found suffocated in the ashes, and the neighbouring streams were strewed with dead fish. When we consider the amazing quantity of stones and ashes ejected in these and similar instances by volcanic power, we cannot wonder that considerable mountains have frequently been piled up by one single eruption. Thus in the Bay of Baise near Naples, Monte Nuovo, a hill 440 feet high, and with a base of more than a mile and a half in circumference, formed, in less than twelve hours, on September 29, 1538 ; and a few days gave birth to Monte Minardo, near Bronte, on the slopes of Etna, which rises to the stiU. more considerable height of 700 feet. It would be curious to calculate how many thousands of workmen, and what length of time, man would need to raise mounds like these, produced by an almost instantaneous effort of nature. In other cases the expansive power of the elastic vapours, which cast up these prodigious masses from the bowels of the earth, is such as to blow to pieces the volcanic cone through which it seeks its vent. In Quito there is an ancient tradition that Capac Urcu, which means ' the chief,' was once the highest volcano near the equator, being higher than Chimborazo, but at the beginning of the fifteenth centuiy a prodigious eruption took place which broke it down. The fragments of trachyte, says F 2 68 THE SUBTERRANEAN WORLD. Mr. Boussingault, which once formed the conical summit of this celebrated mountain, are at this day spread over the plain. On August 11, 1772, the Pepandajan, in Java, formerly one of the highest mountains of the island, broke out in eruption ; the inhabitants of the country around pre- pared for flight, but, before they could escape, the greater part of its summit was shivered to pieces and covered the neighbourhood with its ruins, so that in the upper part of the Gurat valley forty villages were completely buried. During the dreadful eruption of 1816, the Temboro, in Sumbawa, is said to have lost at least one-third of its height from the explosion of its summit, and similar instances are mentioned as having occurred among the volcanoes of Japan. In the year 1638 a colossal cone called the Peak, in the Isle of Timor, one of the Moluccas, was entirely destroyed by a paroxysmal explosion. The whole mountain, which was before this continually active, and so high that its light was visible, it is said, three hundred miles oif, was blown up and replaced by a concavity now containing a lake. Again, according to M. Moreau de Jonnes, in 1718, on March 6-7, at St. Vincent's, one of the Leeward Isles, the shock of a terrific earthquake was felt, and clouds of ashes were driven into the air, with violent detonations, from a mountain situated at the eastern end of the island. When the eruption had ceased, it was found that the whole mountain had disappeared like the baseless fabric of a dream. The disastrous effects of the showers of sand, pumice, and lapilli ejected by a volcanic eruption are increased by the transporting power of water. The aqueous vapours which are evolved so copiously from volcanic craters during erup- tions, and often for a long time subsequently to the discharge of scoriae and lava, are condensed as they ascend in the cold atmosphere surrounding the high volcanic peak ; and the clouds thus formed, being in a state of high electrical tension,, give rise to terrific thunderstorms. The lightning flashes in all directions from the black canopy overhanging the moun- tain, the perpetually rolling thunder adds its loud voice to the dreadful roar of the labouring volcano, while torrents of rain, sweeping along the light dust and scorise which they WARNINGS OP COMING ERUPTION. 69 carry down with them from the air, or meet with on their way, produce currents of mud, often more dreaded than streams of lava, from the far greater velocity with which they move. It not seldom happens that the eruptions of volcanoes rising above the limits of perpetual snow are preceded or accompanied by the rapid dissolution of the ice which clothes their summits or their sides, owing to the high temperature imparted to the whole mass of the mountain by the vast conflict raging within. Thus in January 1803 one single night suiEced to dissolve or sweep away the enormous bed of snow which in times of rest covers the steep cone of Cotopaxi (18,858 feet high), so that on the following morning the dark mountain, divested of its brilliant robe, gave warning to the affrighted neighbourhood of the terrific scenes that were about to follow. ' The volcanoes of Iceland, which mostly rise in the midst of vast fields of perpetual ice, fre- quently exhibit this phenomenon. On October 1 7, 1 758, the eruptive labouring of Kotlingia gave birth to three enormous torrents, which carried along with them such masses of glacier fragments, sand, and stones as to cover a space fifty miles long and twenty-five miles broad. Blocks of ice as large as houses, and partly bearing immense pieces of stone on their backs, were hurried along by the floods ; and soon after the eruption took place with a terrific noise. A very singular phenomenon sometimes occurs in the gigantic volcanoes of the Andes. By the infiltration of water into the crevices of the trachytic rock of which they are composed, the caverns situated at their declivities or at their foot are gradually changed into subterranean lakes or ponds, which frequently communicate by narrow apertures with the Alpine brooks of the highlands of Quito. The fish from these brooks live and multiply in these subterranean reser- voirs thus formed, and when the earthquakes which precede every eruption of the Andes chain shake the whole mass of the volcano, the caverns suddenly open and discharge enormous quantities of water, mud, and small fish. When in the night between the 19th and 20th of June 1698, the summit of Carguairazo (18,000 feet high) was blown up, so that of the whole crater-rim but two enormous peaks 70 THE SUBTEKRANEAN WO.ELD. remained, the inundated fields were covered, over a surface of nearly fifty square miles, with fluid tuff and clay-mud en- veloping thousands of dead fish. Seven years before, the malignant fever which prevailed in the mountain-town of Ibarra to the north of Quito was attributed to the effluvia arising from the putrid fish ejected by the volcano of Im- baburu. Amidst all these terrible phenomena — the dreadful noise, the quaking of the earth, the ejection of stones and ashes — which, often continuing for weeks or months, shake the deepest foundations of the volcano, fiery streams of liquid lava gush forth sooner or later as from a vase that is boiling over. Their appearance generally indicates the crisis of the subterranean revolution, for the rage of the elements, which until then had been constantly increasing, diminishes as soon as the torrent has found sm outlet. The lava rarely issues from the summit crater of the mountain ; much more frequently it flows from a lateral rent in the volcano's side, which, weakened and dislocated in its texture by repeated shocks, at length gives way to the immense pressure of the lava column boiling within. From the vast size of these eruptive rents, we may form some idea of the gigantic power of the forces which give them birth. Thus during the great eruption of Etna in 1669, the south-east flank of the mountain was split open by an enormous rent twelve miles long, at the bottom of which incandescent lava was seen. The extreme length of the fissure which gave la.teral issue to the lava of Kilauea in 1840 was twenty-five miles, as could distinctly be traced through the disturbance of the surface rocks above; and in the terrific eruption of Skaptar Jokul, which devastated the west coast of Iceland in 1783, lava gushed forth from several vents along a fissure of not less than 100 miles in length. In some cases the whole mass of the volcano has been cleft in two. Vesuvius was thus rent in October 1822 by an enormous fissure broken across its cone in a direction N.W.— S.E. Here and there along the line of such a rent, cones of eruption are thrown up in succession at points where the gaseous matter obtains the freest access to the surface, and LAVA STREAMS. 71 has power to force up lava and scoriEB. Few indeed, if any, of the greater volcanic mountains are unattended by such minor elevations, clustering about its sides like the satellites of a planet. Professor Dana found Mauna Loa covered with numerous parasitic cones, and Mr. Darwin counted several thousands on one of the Gallapagos Islands. On the flanks of Etna, according to Professor Sartorius von Waltershausen, more than 700 of them are to be seen, almost all possessing craters, and each marking the source of a current of lava. Though they appear but trifling irregularities when viewed from a distance as subordinate parts of so imposing and colossal a mountain, many of them would nevertheless be deemed hills of considerable height in almost any other region. The double hill near Mcolosi, called Monte Eossi, formed in 1669, is 450 feet high and two miles in cir- cumference at its base; and Monte Minardo, near Bronte, on the east of the great volcano, is iipwards of 700 feet in height.* ' On looking down from the lower borders of the desert region of Etna,' says Sir Charles Lyell, 'these minor volcanoes, which are most abundant in the woody region, present us with one of the most delightful and characteristic scenes in Europe. They afibrd every variety of height and size, and are arranged in beautiful and picturesque groups. However uniform they may appear when seen from the sea, or the plains below, nothing can be more diversified than their shape when we look from above into their craters, one side of which, as we have seen, is generally broken down. There are indeed, few objects in nature more picturesque than a wooded volcanic crater. The cones situated in the higher parts of the forest zone are chiefly clothed with lofty pines, while those at a lower elevation are adorned with chestnuts, oaks, and beech-trees.' As the point where a lava-current flnds a vent is often situated at a considerable distance below the surface of the liquid column in the internal chinmey of the volcano, the pressure from above not seldom causes the lava to spout forth in a jet, until its level in the crater shaft has been reduced to that of the newly-formed orifice. Thus, when * See p. 67. 72 THE SUBTERRANEAN WORLD. Vesuvius was rent by tlie dreadful paroxysmal eruption of 1794, the lava was seen to shoot up in magnificent fountains as it issued from the openings along the fissure. Further on, the lava flows down the mountain's side according to the same laws which regulate the movements of any other stream, whether of water, mud, or ice : more rapidly down an abrupt declivity, slower where the slope is more gradual; now accumulating in narrow ravines, then spreading out in plains ; sometimes rushing in fiery cas- cades down precipices, and, where insurmountable obstacles oppose its progress, not seldom breaking off into several branches, each of which pursues its independent course. At the point where it issues, the lava flows in perfect so- lution, but, as its surface rapidly cools when exposed to the air, it soon gets covered with scoriae, which are dashed over each other in wild confusion, by successive floods of liquid stone, so as to resemble a stormy sea covered with ice-blocks. But the liquefied stone not only hardens on its external sur- face ; it also becomes solid below, where it touches the colder soil, so that the fluid lava literally moves along in a crust of scoriae, which lengthens in the same proportion as the stream advances. The movements of the lava-current are of course consider- ably retarded by the formation of scoriae, so that, unless where a greater inclination of the soil gives it a new impulse, it flows slower and slower. Thus the lava-stream which was ejected by Etna during the great eruption of 1669, performed the flrst thirteen Italian miles of its course in twenty days, or at the average rate of 162 feet per hour, but required no less than twenty- three days for the last two miles. While mov- ing on, its surface was in general a mass of solid rock ; and its mode of advancing, as is usual with lava streams, was by the occasional fissuring of the solid walls. Yet, in spite of the tardiness of its progress, the inhabitants of Catania watched its advance with dismay, and rushed into the churches to invoke the aid of the Madonna and the Saints. One citizen only, a certain Baron Papalardo, relied more upon his own efforts than upon supernatural assistance, and set out with a party of fifty men, dressed in skins to protect them from the heat, and armed with iron crows and hooks for PROJECTION OP LAVA INTO THE SEA. 73 tlie purpose of breaking open one of the solid walls of scorite that flanked the liquid current, so as to divert it from the menaced city. A passage was thus opened for a rivulet of melted matter, which flowed in the direction of Paterno ; but the inhabitants of that town being alarmed for their safety, took up arms against Papalardo, whose fifty workmen would hardly have been able to cope with the powers of nature. Thus, slowly but irresistibly, the lava advanced up to the walls of Catania, which, being formed of huge Cyclopean blocks, and no less than sixty feet high, at first stemmed the fiery stream. But the glowing floods, pressing against the rampart, rose higher and higher, and finally reaching its summit, rushed over it in fiery cataracts, and destroying part of the town, at length disgorged themselves into the sea, where they formed a not inconsiderable promontory. A txTily gigantic conflict might naturally be expected from the meeting of two such powerful and hostile bodies as fire and water. This, however, is by no means the case, for as soon as the lava enters the sea, the rapid evaporation of the water that com.es into immediate contact with it accele- rates the cooling of the surface and thickens the hard external crust to such a degree that very soon all communication is cut off between the water and the fiery mass. While the lava continues to advance from the land, the crust of scoriifi is prolonged in the same proportion, and should it be rent here and there, steam is at once developed with such violence as to prevent all further access of the water into the interior of the fissures. Thus, Breislak informs us that, in 1794, the eruption of a lava-stream into the Bay of Naples, near Torre del Greco, took place with the greatest tranquillity, so that he himself was able to observe the advancing of the lava into the sea while seated in a boat immediately near it, without being disturbed by explosions or any other violent pheno- menon. As the crust of scorise is so bad a conductor of heat, it occasions a very slow cooling and hardening in the interior of the lava-stream, forming as it were a vessel in which the liquid fire can be retained and preserved for a long time. When Elie de Beaumont visited the lava-stream of Etna, nearly two years after its eruption in 1832, its interior was 74 THE SUBTEKRANEAN WORLD. still so warm that lie could not hold his finger in the hot steam issuing from its crevices. It has also been proved, on trustworthy evidence, that after twenty- five and thirty years, many lava-strea.ms of Etna still continued to emit heat and steam ; and after twenty-one years it was possible to light a cigar in the crevices of the lava that issued froiu JoruUo in 1759. Another extremely curious effect of the scoriae being such bad conductors of heat is, that masses of snow will remain unmelted, though a lava-stream rolls over them. Thus, in 1787, the lava of Etna flowed over a large deposit of snow, which, however, was by no means fully liquefied, but remained for the greatest part entire, and gradually changed into a granular and solid mass of ice. This was traced in 1828, by the geologist Gemellaro, for a distance of several hundred feet under the lava, and most likely still reposes under it as in an ice-cellar. The cliffs which form the vast crater-ring of the Isle of Deception, in the extreme Southern Atlantic, are like- wise composed of alternate layers of ice and lava. Probably in both these cases the ice-beds had been covered before the lava flowed over them, by a rain- of scorise and volcanic sand, which is so well known among the shepherds in the higher regions of Etna as a bad conductor of caloric, that, to obtain a supply of water for their herds during the summer, they cover some snow a few inches deep with volcanic sand, which entirely prevents the penetration of solar heat. Most of the recent lava-streams evolve from all their fis- sures and rents a quantity of vapour, so as to be dotted with innumerable fumaroles, and to exhibit, as they flow along, a smoking surface by day and a luminous one by night. At first these fumaroles are so impetuous that they frequently puff up the lava-crust around their orifices into little cones or hillocks, consisting of blocks of scorise irregularly piled up over each other, and from whose summit the vapours con- tinue to ascend. As the mass cools, they are naturally less- ened in numbers and in power ; but in 1803 Humboldt still saw fumaroles from twenty to thirty feet high, rising from the small cones which covered by thousands the great lava- stream of JoruUo of the year 1759. The vast dimensions of single lava-streams give proof of SKAPTAR JOKULL AND MAUNA LOA. 75 the enormous powers which forced them out of the bowels of the earth. The lava-stream of Vesuvius which destroyed Torre del Greco in 1794, is 17,500 French feet long, and when it reached the town was more than 2,000 feet wide and forty feet deep. While this mighty mass of molten stone, the volume of which has been reckoned at about 467 millions of cubic feet, was descending towards the sea, another stream, whose mass is computed at about one-half of that of the for- mer, was flowing in the direction of Mauro. This single eruption has therefore furnished more than 685 millions of cubic feet of lava, equal to a cube of 882 feet, in which at least a dozen of the largest churches, palaces, and pyramids on earth might conveniently find room. If to the solid lava we add the astonishing quantities of scoriee, sand, and ashes thrown out by this same eruption, we may form some idea of the masses of matter which were in this one instance ejected from the interior of the earth. The volume of the lava-stream which flowed from the vol- cano of the Isle of Bourbon in the year 1787 is estimated at 2,526 millions of cubic feet ; but even this astonishing ejection of molten stone is surpassed by that which took place during the eruption of Skaptar JokuU* in 1783, when the lava rolled on to a length of fifty miles, and, on reaching the plain, expanded into broad lakes, twelve and fifteen miles in diameter and a hundred feet deep. In the great eruption of Mauna Loa, which commenced on the 30th of May 1840, the lava began to flow from a small pit-crater called Avare, about six miles from Kilauea. The light was seen at a distance, but, as there was no popu- lation in that direction, it was supposed to proceed from a jungle on fire. The next day another outbreak was perceived farther towards the coast, and general alarm prevailed among the natives, now aware of the impending catastrophe. Other openings followed, and by Monday the 1st of June the large flow had begun, which formed a continuous stream to the sea, which it reached on the 3rd. This flood issued from several flssures along its whole course, instead of being an overflow of lava from a single opening ; it started from an * A detaUed account of this eruption, one of tlie most dreadful on record, is given in ' The Polar World,' chap. vi. p. 81. 76 THE SUBTERRANEAN WORLD. elevation of 1,244 feet, as determined by Captain Wilkes, at a point twenty-two miles distant from the first outbreak, and twelve from the shore. The scene of the flowing lava, as we are told by those who saw it, was indescribably magnificent. As it rolled along it swept away forests in its course, at times parting and inclosing islets of earth and shrubbery, and at other times undermining and bearing along masses of rock and vegetation on its surface. Finally, it plunged into the sea with loud detonations, and for three weeks continued to disgorge itself with little abatement. The light which it emitted converted night into day over all eastern Hawaii. It was distinctly visible for more than one hundred miles at sea, and at the distance of forty miles fine print could be read at midnight. As previous to the eruption, the whole vast pit of Kilauea had been filled to the brim with the lava, which, bursting through the fianks of the mountain, thus found a vent towards the sea, we have some means of estimating the volume of the ejected masses in the actual cubic contents of the emptied pit. The area of the lower pit, as determined by the surveys of the American Exploring Expedition, is equal to 38,600,000 square feet. Multiplying this by 400 feet, the depth of the pit after the eruption, we have 15,400,000,000 cubic feet for the solid contents of the space occupied by lava before the eruption, and therefore the actual amount of the material which fiowed from Kilauea. This is equivalent to a triangular range 800 feet high, two miles long, and over a mile wide at base ! Though generally symptoms of violent disturbance, such as shakings of the earth and laud, thundering noises, precede the eruption of lava, yet this is not always the case. Thus the craters of Mount Kea have frequently disgorged their masses of molten stone without such accompanying phe- nomena. In 1843, when the volcano poured out a flood of lava, reaching for twenty-five miles down its side, all took place so quietly that persons at the foot of the mountain were unaware of it, except from the glare of light after the action had begun. Through its progress no sounds were heard below, nor did it cause any perceptible vibrations, except in the region of the outbreak, and there none of much violence. PEOGRESS OP LAVA STKBAMS. 77 Tlie lava sometimes cools down with a smooth, solid, undu- lating surface, marked with rope-like lines and concentric folds, such as are seen on any densely viscid liquid if drawn out as it hardens ; but much more frequently it appears as if shattered to a chaos of ruins. The fragments vary from one to hundreds of cubic feet, or from a half-bushel measure to a house of moderate size. They are of all shapes, often in angular blocks, and sometimes in slabs, and are horribly rough, having deep recesses everywhere among them. The traveller shudders as his path leads him over a lava-field, thus bristling with myriads of spikes, where the least false step would precipitate him into the deep cavities, among the jagged surfaces and edges. This scene of horrid confusion often extends for miles in every direction, and, viewed from its central part, the whole horizon around is one wide waste of gray and black desolation, beyond the power of words to describe. The breaking up of a lava-field into chaotic masses evi- dently proceeds from a temporary cessation, either complete or partial, and a subsequent flow of a stream of lava. The surface cools and hardens as soon as the stream slackens ; afterwards there is another heaving of the lava, and an onward move, owing to a succeeding ejection or the removing of an obstacle, and the motion breaks up the hardened crust, piling the masses together, either in slabs or huge angular fragments, according to the thickness to which the crust had cooled. If the motion of a lava-stream be quite slow, the cooling of the front of it may cause its cessation, thus damming it up and holding it back, till the pressure from gradual accumulation behind sweeps away the barrier. It then flows on again, carrying on its surface masses of the hardened crust — some, it may be, to sink and melt again, but the larger portion to remain as a fleld of clinkers. The breaking-up of the ice of some streams in spring gives some idea of the manner in which the hardened masses of a lava-field are piled up as it moves along; but to form a just idea of the greatness of the effect, the mind must bring before it a stream, not of the scanty limits of most rivers, but one, not unfrequently, of several miles in breadth : besides, in place of slabs of pure and clear ice, there should be sub- 78 THE SUBTERRANEAN WORLD. stituted shaggy heaps of black scoriae, and a depth or thick- ness of many yards in place of a few inches. Where volcanic mud-streams have flooded the land, or a rain of ashes and light scoriae has descended upon the soil, its fertility may soon be restored under the influence of a sunny sky ; but as far as the lava reaches, a stony wilderness often remains for ages, particularly in the colder regions of the earth. Thus, though many of the lava-fields of Iceland have existed long before the first Scandinavian colonists settled in the land, their surface is generally as naked as when they first issued from the volcano ; and where signs of vegetation may be seen among their fragments, the eye finds nothing to relieve the horrid monotony of the scene but spare patches of lichen and mosses, or here and there some dwarf herb or shrub that hardly ventures to peep forth from the crevice in which it has found a shelter. But in a milder climate, such as that of Italy, and still more rapidly in the torrid zone, the horrid nakedness of a lava-field undergoes a more rapid transformation, provided a sufficient moisture favours the growth of plants. The rains promote the decom- position of the lava, and a rank vegetation succeeds, which in its turn assists the work of decomposition, and thus hastens the accumulation of soil. Ferns and grasses spring up in the nooks and crevices, and finally the vine or the taro flourish luxuriantly, for nothing can exceed the fertility of a disintegrated lava-field. Volcanoes have frequently been considered as safety-valves, which, by affording a vent to subterranean vapours, preserve the neighbouring regions from the far more disastrous and wide-spreading effects of earthquakes ; and facts are not wanting which seem to justify this opinion. After the soU had trembled for a long time throughout the whole of Syria, in the Cyclades, and in Euboea, the shocks suddenly ceased when, in the plains near Chalcis, a stream of ' glowing mud ' (lava from a crevice) issued from the bowels of the earth. Stnibo, who relates this incident, adds that ' since the craters of Etna have been opened, through which fire ascends, the land on the sea-coast is less subject to earthquakes than at the time when all vents on the surface were stopped up.' Before the earthquake which destroyed the town of STATE OF THE EARTH'S INTERIOE. 79 Eiobamba, the smoke of the volcano of Pasto, which is 200 miles distant, disappeared. The Neapolitans and Sicilians consider the eruptions of Vesuvius and Etna, or even a more lively activity of these volcanoes, as a certain preservative against devastating earthquakes, and we meet with the same belief among the inhabitants of Quito and Peru. But in many cases this fancied security has proved to be delusive, as very violent earthquakes have not seldom been found to accompany volcanic eruptions. The great Chilian earth- quake of 1835 coincided with an eruption of Antuco ; and the shocks which agitated all Kamtschatka and the long chain of the Kurilian Islands, in 1737, occurred simultaneously with an eruption of Khutschewskaja Skopa. Professor Dana doubts whether action so deep-seated as that of the earthquake must be can often find relief in the narrow channels of a volcano miles in length. He points out the example of Mauna Loa, where lavas are frequently poured out from the summit crater, at an elevation of more than 10,000 feet above Kilauea, so that the latter, notwith- standing its extent, the size of its great lakes of lava, and the freedom of the incessant ebullition, is not a safety-valve that can protect even its own immediate neighbourhood. In his opinion volcanoes might more fitly be called indexes of danger. They point out those portions of the globe which are most subject to earthquakes, and are results of the same causes that render a country liable to such convulsions. The phenomena attending an eruption can leave no doubt that below every active volcano a large subterranean cavity must exist in which melted lava accumulates. The partisans of the theory which supposes the earth to consist of a central fluid mass with a solid shell resting upon it, attribute the formation of volcanoes to rents or fissures in this crust through which the lava is cast forth ; but the local development of heat by chemical action, or some other unknown cause, is quite sufficient to account for the existence of fiery lakes im- bedded in a solid mass, and which, though insignificant when compared with the surface of the globe, may still be large enough to produce volcanic phenomena on the grandest scale. The cause of the reaction of such a reservoir against the surface of the earth must in all probability be sought for in 80 THE SUBTEREANEAN A\'OELD. the expansive force of steam ; for when water, penetrating through, crevices or porous strata, comes in contact with the heated subterranean mass, it is evident that the steam thus generated must press upon the lava, and, when formed in sufficient quantity, ultimately forces it up the duct of the volcano. In other cases, we may suppose a continuous column of lava mixed with liquid water raised to a red-hot, or white-hot, temperature under the influence of pressure. A disturbance of equilibrium may first bring on an eruption near the surface, by the expansion and conversion into gas of the entangled water, so as to lessen pressure. More and more steam would then be liberated, bringing up with it jets of liquid rock, and ultimately ejecting a continuous stream of lava. Its force being spent, a period of rest suc- ceeds, until the conditions for a new outburst (accumulation of steam and melted rock) are obtained, and another cycle of similar changes is renewed. The important part which water plays in volcanic action is moreover sufficiently proved by the enormous quantity of steam which is poured forth during every eruption, or is constantly escaping in the fumaroles of a crater. The various gases (carbonic, muriatic, sulphurous) which are likewise exhaled by volcanoes may also have been rendered liquid by pressure at great depths, and may assist the action of water in causing eruptive outbursts. The great number of active volcanoes on sea-coasts and in islands like- wise points to the agency of water in volcanic operations ; and in the few cases where eruptive cones are situated far inland, their situation on the borders of a lake, or their cavernous and porous structure, accounts for the absorption of a quantity of atmospheric water, sufficient for the produc- tion of volcanic phenomena. ' 1 1 I 'l llllll'll'lilll ll I 1 1 llj III Hi _ _ j 4 ,™ilL .■ 81 CHAPTER VII. DESTEUOTION OP HEEOULANEUM AND POMPEII. State of Vesuvius before the eruption in the year 79 a.c— Spartacus — Premonitory Earthquakes — Letter of Pliny the Younger to Tacitus, relating the death of his Uncle, Pliny the Elder — Benevolence of the Emperor Titus — Heroulaneum and Pompeii buried under «• muddy alluvium — Herculaneum first discovered in 1713. OF all the volcanic eruptions recorded in history there is none more celebrated than that which, on the 23rd of August, A.D. 79,buried the towns of Herculaneum andPompeii under a deluge of mud and ashes. Many other eruptions have no doubt been on a grander scale, or may have spread ruin and desolation over a wider area, but never has a vol- cano, awakening from the slumber of a thousand years, de- vastated a more smiling paradise than the fields of happy Campania, or buried more beautifal cities. Before that terrible catastrophe. Mount Vesuvius, now con- stantly smoking, even in times of rest, had, ever since the first colonisation of South Italy by the Greeks, exhibited no signs of volcanic activity. Even tradition knew of no previous dis- turbance. No subterranean thunder, or sulphurous steams, or cast-up ashes, gave token of the fires slumbering beneath its basis; and the real nature of the apparently so peaceful mountain could only be conjectured from the similarity of its structure to other volcanoes, or from the ancient lava- streams that furrowed its abrupt declivities. At that time also its shape was very different from its present form, for instead of two apices, it exhibited, from a distance, the re- gular outlines of a sharply truncated cone. Plutarch relates that rough rock walls, piled round its summit, and overgrown with wild vines, inclosed the waste of the crater. G 82 THE SUBTERRAM'EAN WORLD. When, in 73 B.C., Spartacus, with seventy of his comrades, broke the fetters of an insupportable slavery, he found a secure retreat in this natural stronghold, which could only be scaled by a single narrow and difficult path. By degrees 10,000 fugitive slaves gathered round his standard, and Rome began to tremble for her safety. The praetor Clodius led an army against the rebels, and surrounded the mountain ; but Spartacus caused ropes to be made of the branches of wild vines, by means of which he, with the boldest of his followers, was let down from the rocks, where they were supposed to be totally inaccessible, and, falling unawares upon the praetor, put his troops to flight and took his camp. The declivities of the mountain, thus become historically renowned, were covered with the richest fields and vineyards, and at its foot, along the beautiful Bay of Naples, lay the flourishing towns of Herculaneum and Pompeii, the seats of luxury and refine- ment. Who could, then, have imagined that this charming scene was so soon to be disturbed in so terrible a manner, and that the time was nigh when the ancient volcanic channels, from which, in unknown ages, lava-streams and ashes had so frequently broken forth, were once more to be re-opened ? The first sign which announced the awakening energies of the volcano was an earthquake, which, in 63 a.d. devastated the fertile regions of Campania. From that time to the crowning disaster of 79, slight tremors of the earth frequently occurred, until, finally, the dreadful eruption took place which Pliny the Younger so vividly describes in his celebrated letter to Tacitus. ' My uncle,' says the Roman, ' was at Misenum, where he commanded the fleet. On the 23rd of August, about one o'clock in the afternoon, my mother informed him that a cloud of an uncommon size and form was seen to arise. He had sunned himself (according to the custom of the ancient Romans), and taken his usual cold bath, then dined, and studied. He asked for his sandals, and ascended an eminence, from which the wonderful phenomenon could be plainly seen. The spot from whence the cloud ascended, in a shape like that of an Italian pine-tree, could not be ascertained on account of the distance ; its arising from Vesuvius only subsequently became known. RENEWED ACTIVITY OF VESUVIUS. 83 ' In some parts it was white, in others black and spotted, from the ashes and stones which it carried along. To my uncle, being a learned man, the phenomenon seemed impor- tant, and worthy of a closer investigation. He ordered a light ship to be got ready, and left it to my option to accom- pany him. I answered that I preferred studying, and by chance he himself had given me something to write. He was on the point of leaving the house when he received a letter from Eesina, the inhabitants of which, alarmed at the impending danger — the place lay at the foot of the mountain, and escape was only possible by sea — begged him to help them in their great distress. He now changed his plan, and executed as a hero the undertaking to which he had been prompted as a natural philosopher. ' He ordered the galleys of war to set sail, and embarked to bring help, not only to Resina, but to many other places along the coast, which, on account of its loveliness, was very densely peopled. ' He hastens to the spot from which others are taking flight, and steers in a direct line towards the seat of danger, so un- concerned as to dictate his observations upon all the events and changes of the catastrophe, as they passed before his eyes. ' Already ashes fell upon the ship, hotter and thicker on approaching, as also pum.ice and other stones blackened and burnt by fire. Suddenly a shallow bottom, and the masses ejected by the eruption, rendered the coast inaccessible. He hesitated for a moment whether he should sail back again, but, soon resolved, said to the steersman who advised him to do so, " Fortune favours the bold ; steer towards the villa of Pomponianus." This friend resided at Stabise, on the opposite side of the bay, where the danger, although as yet at some distance, was still within sight, and menacing enough. Pomponianus had therefore caused his effects to be conveyed on boa.rd a ship, intent on flight so soon as the contrary wind should have abated. As soon as my uncle, to whom it was very favourable, has landed, he embraces, consoles, encourages his terrified friend, takes a bath to relieve his fears by his own confidence, and dines after the bath with perfect com- posure, or, what is no less great, with a serene countenance. o 2 84 THE SUBTERRANEAN WORLD. ' Meanwliile high columns of flame burst forth from Vesu- vius in various places, their brilliancy being increased by the darkness of the night. My uncle, with the intention of re- lieving apprehension, said that they proceeded from the villas which, abandoned by their terrified proprietors and left a prey to the flames, were now burning in solitude. He then retired and slept soundly, for his attendants before the door heard him fetch his breath, which, on account of his corpu- lence, was deep and loud. But now the court, into which the room opened, became filled to such a height with ashes and pumice that by a longer delay he would not have been able to leave it. They awaken him, he rises, and greets Pomponianus and the others who had watched. They con- sult together, whether to remain in the house or to flee into the open air, for the ground trembled from the repeated and violent shocks of the earth, and seemed to reel backwards and forwards. On the other hand, they feared in the open air the falling of the pumice-stones and cinders. On com- paring these two dangers, flight was chosen ; and, as a pro- tection against the shower of stones, they covered their heads with cushions. Everywhere else the day was already far advanced, but the blackest night still reigned at Stabiss. Provided with torches, they resolved to seek the shore, in order to ascertain whether they could venture to embark, but the sea was found to be too wild and boisterous. ' My uncle now lay down upon a carpet, and asked for some cold water, of which he repeatedly drank. The flames and their sulphurous odour _ drove away his comj)anions, and forced him to rise. Leaning on two slaves, he tried to move, but immediately sank down again, suffocated as I believe by the dense smoke, and by the closing of his larynx, which was by nature weak, narrow, and subject to frequent spasms. On the third morning after his death, the body was found without any marks of violence, covered with the clothes he had worn, and more like a person sleeping than a corpse.' Thus perished, in his fifty-sixth year, one of the greatest naturalists and noblest characters of ancient Eome, the philosopher to whom we are indebted for the first general description of the world — a work which, in spite of its -nume- rous imperfections and errors, is one of the most interesting monuments of classical literature. DESTRUCTION OF POMPEII. 85 Wlien tlie rage of the volcanic powers had subsided, the sun, now no longer obscured by clouds of ashes, shone upon a scene of utter desolation, where nature, embellished by art, had, but a few days before, appeared in all her loveliness. The mountain itself had changed its form, and rose with new peaks to the skies ; a thick layer of stones and dust had settled with the curse of sterility on the fields ; thousands of homeless wretches wandered about disconsolate, and three towns — Pompeii, Herculaneum, Stabiee — had disappeared to be brought to light again in a wonderful manner after the lapse of many centuries. This great catastrophe gave the Emperor Titus a fine opportunity for displaying the benevolence which entitled him to be called ' the delight of mankind.' He immediately hastened to the scene of destruction, appointed guardians of consular rank to distribute among the needy survivors the property of those who had perished without heirs ; and encouraged the weak-hearted, assisting them by liberal donations, until a no less terrible misfortune recalled him to Rome, where a fire, which laid almost half the town in ashes, was followed by a plague, which, for some time, daily swept away thousands. It has often been asked how so many of the relics buried in Herculaneum and Pompeii could have been so perfectly preserved as to form a Museum of the Past for the admira- tion and instruction of future ages. A stream of lava would undoubtedly have consumed everything on its fiery track, but, fortunately for posterity, it was not a flood of molten stone, but a current of mud which overwhelmed the devoted cities. We learn from history that a heavy shower of sand, pumice, and lapilli was ejected by Vesuvius for eight successive days and nights, in the year 79, accompanied by violent rains, and thus all these volcanic matters were converted into mud- streams, which, rushing down the sides of the mountain, descended npon Herculaneum and Pompeii. This circum- stance satisfactorily explains how the interior of the buildings, with all the underground vaults and cellars, was filled up, and how all the objects they contained could be as perfectly moulded as in a plaster cast by the muddy alluvium, which subsequently hardened into pumice tuff. Hence this wonder- 86 THE SUBTEERANEAN WORLD. ful preservation of paintings, whicli, shielded from the destructive influence of the atmosphere, still retained their original freshness of colour when again brought to light by a late generation; these rolls of papyrus which it has been found possible to decipher; this perfect cast of a woman's form, with a child in her arms ! No lava has flowed over Pompeii since that city was buried, but with Herculaneum the case is different. Although the substance which fills the interior of the buildings in that doomed city must have been introduced in a state of mud like that found in similar situations in Pompeii, yet the superincumbent mass differs wholly in composition and thickness. Herculaneum was situated several miles nearer to the volcano, and has, therefore, been always more liable to be covered, not only by showers of ashes, but by alluvium and streams of lava. Accordingly, masses of both have accumu- lated on each other above the ancient site of the city, to a depth of nowhere less than 70, and in many places of 112 feet; while the depth of the bed of ashes under which Pompeii lies buried seldom exceeds 12 or 14 feet above the houses, and it is even said that the higher part of the amphitheatre always projected above the surface. Yet, strange to say, Herculaneum, though far more pro- foundly hidden, was discovered before Pompeii, by the accidental circumstance that a well sunk in 1713 came right down upon the theatre where the statues of Hercules and Cleopatra were found. Many others were afterwards dug out and sent to Prance by the Prince of Elbeuf, who, having married a Neapolitan princess, became proprietor of the field under which the theatre lies buried. Purther exca- vations were, however, forbidden by Government, and only resumed in 1736. But the difiiculty of removing the large masses of lava accumulated above the city, and the circum- stance of its partly lying under the modern towns of Portici and Resina have confined the exploration of Herculaneum within narrow limits. The large theatre alone is open for inspection, and can be seen only by torchlight, so that its dark galleries, cut through the tTiff, are but seldom visited by strangers; while no traveller leaves Naples without KUINS OF HERCULANBUM. 87 having wandered througli tlie ruins of Pompeii, for Italy hardly affords a more interesting sight than that of these streets and forums, these theatres and temples, these houses and villas, vrhich require but the presence of their ancient inhabitants to complete the picture of a Roman town, such as it was eighteen hundred years ago, 88 THE SUBTERRANEAN WORLD. CHAPTER Vni. GAS SPRINGS AND MUD VOLCANOES. Carbonic-acid Springs — Grotto del Cane — The Valley of Death in Java — Exagge- rated Descriptions — Carburetted Hydrogen Springs — The Holy Eires of Baku — Description of the Temple — Mud Volcanoes — The Macaluba in Sicily — Crimean Mud Volcanoes —Volcanic Origin of Mud Volcanoes. THE numerous gas springs whieli in many countries are evolved from an unknown depth, afford us a convinc- ing proof tliat the remarkable chemical transformations of which we find so many traces in the past history of our planet are still perpetually taking place in many of the mysterious crevices and hollows of the earth-rind. In Auvergne, the Vivarrais, the Eifel, and along the whole basaltic range from the Rhine to the Riesengebirge in Silesia, carbonic acid gas is exhaled in incredible quantities from the vast laboratories of the subterranean world. Professor Bischoff found that a single gas spring near Burgbrohl daily produced 5,650 cubic feet of carbonic acid, a quantity amounting in the course of a year to no less than 262,000 pounds in weight ; and, according to Bromeis, the great Artesian spring at Nauheim evolves every minute 71 cubic feet of carbonic acid, equal to a weight of 6,000,000 pounds annually. If from these two instances we judge of the produce of the many carbonic acid gas springs of Germany, and if we farther extend our view to the rest of the world, in many parts of which carbonic acid probably escapes in still greater quantities, we can form some idea of the geological importance of these springs, which also exercise no small influence upon the organic world. For the incalculable masses of carbonic acid which are thus constantly pouring from subterranean vents into the atmo- spheric ocean are again absorbed by millions of plants. They CARBONIC-ACID SPRINGS. 89 feed tlie forests a,nd the fields; and thus these chemical changes, which are incessantly but imperceptibly modifying the earth-rind, ultimately tend to the advantage of man. As a light dipped in carbonic acid gas is immediately extinguished, and every animal inhaling it is liable to instant suffocation, these properties are sometimes made use of for cruel experiments, for which, among others, the insignificant Grotto del Cane, in the kingdom of Naples — a cave or hole in the side of a mountain near the Lake Agnano — has become notorious. Some miserable dogs are thrust into the stratum of fixed air which covers the bottom of the hole, and are alternately almost choked and resuscitated to satisfy the idle curiosity of tourists. Their violent efforts to escape, when about to be plunged into the poisonous vapour, prove the horrible cruelty of the practice. The carbonic-acid springs in the glen of the Brohl, a small rivulet flowing into the Rhine, near Andernach, are turned to a better purpose, for the manufacture of white lead. The famoiis ' Valley of Death,' or Poison Valley, in the Island of Java, is nothing more than a funnel-shaped hollow, m.easuring about 1 00 feet in diameter at the top, and with a bare space in its centre fifteen feet broad and long, which is frequently covered with a stratum of carbonic acid gas. The sides of the hollow, and even the bottom, with the exception of the above-mentioned naked spot, are everywhere clothed with shrubbery, or even with forest trees. The dead bodies of stags, tigers, wild boars, and birds are said to have been frequently found in the hollow ; but Dr. Junghuhn, the author of a classical work on Java, saw in 1838 but one human corpse lying on its back in the centre of the bare spot. It was still there in 1840, and but slightly de- composed. In 1845 it had been removed, most likely by some compassionate wanderers desirous of giving it a decent burial, for not the slightest trace of the skeleton remained. During the years 1838, 1840, and 1845 Junghuhn visited the Valley of Death no less than thirteen times. When he last saw it, the bodies of six wild hogs were lying at the bottom, all more or less in a state of putrefaction. The crows that were feasting upon their remains proved that a descent might be effected vrithout danger, for, on seeing them hop- 90 THE SUBTERRANEAN WORLD. ping about on the naked soil, even the Javanese entered the circle without hesitation. Not a single trace of carbonic acid was to be perceived, not even when the bold naturalist stretched himself out upon the ground and drew his breath in the crevices and rents with which it is furrowed. Pro- bably the gas never rises more than three feet above the level of the soil, as at this height a luxuriant vegetation begins. This simple description of an accurate observer forms a strange contrast to the gross exaggeration of other travellers, whose accounts, copied in many hand-books, have puffed up a phenomenon hardly superior to that of the Grotto del Cane into something like an eighth wonder of the world. Loudon, who in July 1830 visited the Pakamaran (as the natives call the pit), swells its dimensions to a vast crater about half a mile in circumference, thickly strewn with skeletons of men, tigers, game, and birds of all kinds ; and another recent traveller goes so far as to give it an extent of twenty miles. Next to carbonic acid, but of far less general occurrence, carburetted hydrogen, which gives rise to the wonderful phenomenon of fiery springs, is the gas most frequently evolved by volcanic spiracles. Near Pietra Mala, between Bologna and Florence, on a spot about twelve feet in diameter, several flames rise from the earth, the largest of which ascends to a height of five feet, and is seen burning at night with a pale yellow flame, while its minor satelhtes around are blue tipped with white. No doubt many a terrible legend is attached to this infernal spectacle. Near Barigazzo, between Modena and Pistoja, near the ruins of Velleji, and in many other parts of the volcanic region of the Apennines, similar flames gush out of the ground. The neat little town of Predonia, in the State of New York, on the eastern shore of Lake Erie, is lighted by natural springs of carburetted hydrogen, which, being led into a gasometer, feed the seventy or eighty lamps of the town. The thrifty and practical Chinese, who have preceded us in so many useful discoveries, have for centuries made a like use of the many gaseous emanations in the provinces of Yunnan, Szutschuan, Kuangsi, and Schansi, by leading the BURNING SPRINGS. 91 inflammable air in pipes, wherever they want it for lighting or cooking. But there is no place in the world more remartable for its burning springs than Baku, on the western coast of the Caspian Sea, where the holy and eternal fires are worshipped by the pious Parsees as the special symbol of the Almighty. Like most of the cloisters and convents of the Orient, which are exposed to the incursions of plundering hordes, Aleschga, the temple dedicated to the worship of fire, is a fortified square inclosing a large courtyard, and capable of being defended from the terraced roof. The outer wall forms at the same time the back of the cells, which front the yard. Over the entrance gate, which is situated to the north, rises a high bastion or tower, serving as an additional defence, from the summit of which the visitor enjoys after sunset the fantastic view of the flames which, untarnished by smoke, rise on all sides from rents and crevices in the neighbouring steppe, and wave their bright summits to and fro like tongues of fire. In the centre of the court stands a square tower supported by four columns, and inclosing a basin-like excavation, three or four feet in diameter, into which the gas is conducted by a pipe from sources beyond the walls of the temple. Pour chimneys at the four corners of the tower are fed in a similar manner.' Prom the centre of the tower rises a trident, called Thirsul. The Parsees relate that the Devil once got possession of the earth, and reigned with despotic fury. But man in his distress prayed to the Almighty, and an angel came down and planted this identical trident in the earth as a token that the dominion of his Satanic Majesty had ceased. Eound the court are twenty-two cells, like those of a Catholic convent. They are very small, and, with the exception of a ragged rug, whoUy without furniture ; but each of them is provided with a gas pipe, which can be opened or closed at pleasure, and furnishes light and warmth to the inmate. Near the temple a well has been dug fifty feet deep, in which the gas accumu- lates in larger quantities. Koch (' Wanderungen im Oriente,' 1843-4) tells us that he here enjoyed a sight more won- derful and surprising than any he had ever witnessed before. A carpet was spread over the mouth of the well to prevent 9-2 THE SUBTERRANEAN WORLD. the gas from escaping. After a few minutes, a priest seized a bundle of brushwood, in which a piece of burning paper had been stuck, a.nd flung it into the well, after quickly removing the carpet. The strangers had previously been warned to keep at some distance, and the priest and his assistants likewise ran off as fast as they could. About half a minute after the fire-brand had been cast into the pit, a terrific explosion took place, and a vast column of fire, in the shape of an inverted cone (from the gas spreading out as soon as it emerges from the pit), ascended to the skies. How long the fires of Baku may have been burning is un- known, but it is very probable that they did not exist before the Christian era. No Greek or Roman author mentions them, and it is not before the tenth century that Arab writers take notice of Baku and its wonders. When the Sassan- ides restored the religion of Zoroaster, the attention of these fire-worshipping princes was naturally directed to a place where fire gushes pure and unbidden from the earth. They raised a temple on the spot, and thousands of pilgrims wandered to the holy fires of Baku. But when the fanatical Arabs overthrew the Persian Empire, times of persecution and distress began for the Parsees ; and still later they were almost entirely extirpated by the hordes of Tamerlane. During the last centuries fire-worshipping was again intro- duced by the Indians, who, after the Sefides had ascended the Persian throne, gradually settled in the Caspian pro- vinces, and whose number must have been considerable, as travellers inform us that in the latter half of the seventeenbh century 200 rich Indian merchants were residing in the town of Schemachi. But the anarchical times which fol- lowed the usurpation of Nadir Schah forced most of these Indians to leave their adopted country, and since then only solitary pilgrims have found their way to Baku. But the number even of these is constantly diminishing, although the Russians, to whom the sanctuary now belongs, allow them full freedom of access. When Koch was at Baku, he found there only five Indians from Mooltan, whither the majority would gladly have returned, had they but possessed the necessary means. Their squalid appearance and tattered raiment formed the strongest imaginable contrast to the MUD VOLCANOES. 93 splendour of the element they worshipped. Among them was a Fakir, who had made a vow constantly to remain in the same position absorbed in religious contemplation, and who for sixteen years had never moved from the spot. The burning springs gush out not only from the ground near the temple and in other parts of the peninsula of Abscheron, but even from the bottom of the neighbouring Caspian Sea ; and as Sir Charles Lyell saw carburetted hydrogen rise in countless bubbles through the crystal waters above the falls of the Niagara, and shoot up in bright flames at the approach of a light, so Dr. Abich mentions a spot in the Gulf of Baku where the inflammable gas issues with such force, and in so great a quantity, from the bottom, which is there three fathoms deep, that a small boat is in danger of being overturned when coming too near it. As gas springs most frequently occur in districts which have been the former seats of volcanic action, and as similar exhalations often arise from stiU active craters, they are supposed by many geologists to be the last remaining traces of an expiring volcanic energy. Bischoff considers the car- bonic acid of the German gas springs to be developed by the decomposition of carbonate of lime by volcanic heat or heated water. A phenomenon which is sometimes found connected with gas springs is that of the mud volcanoes, which may be described as cones of a ductile, unctuous clay, formed by the continued evolution of a sulphurous and inflammable gas, spurting up waves and lumps of liquid mud. These remark- able cauldrons are found in many parts of the world, in the Island of Milo, in Italy, in Iceland, in India, about 120 miles from the mouths of the Indus, on the coast of Arracan, in Birmah, in Java, Columbia, Nicaragua, and Trinidad, but probably nowhere on a grander scale than at either extremity of the chain of the Caucasus, towards the Caspian on the east and the Sea of Azof on the west, where in the peninsula of Taman, and on the opposite coast of the Crimea, near Kertsch, vast numbers of mud volcanoes are scattered, some of them 250 feet high. Their operations have apparently been going on for countless ages, and have covered a great extent of land with their products. 94 THE SUBTERRANEAN WORLD. The Macakiba, in Sicily, wliicli owes its name to the Arabs, is the mud volcano most anciently known. It is mentioned by Plato in his ' Pheedon,' and has been described by Strabo. It is situated five miles to the north of Girgenti, on a hill of a conical shape, truncated at the top, and 150 feet high. The summit is a plain Lalf a mile round, and the whole surface is covered with thick mud. The depth of the mud, which is supposed to be immense, is unknown. There is not the slightest appearance of vegetation upon it. In the rainy season the mud is nruch softened ; the surface is even, and there is a general ebullition over it, which is acconi- MUD VOLC/VNOES OF TUIXIDAD. panicd with a very sensible rumbling noise. In the dry season the mud acquires greater consistency, but its motion still goes on. The plain assumes a form somewhat convex ; a number of little cones are thrown up, which rarely rise to the heio-ht of two feet. Each of thein has a crater, where black mud is seen in constant agitation, and incessantly emitting bubbles of air. With these the mud insensibly rises, and as soon as the crater is full of it, it disgorges. The residue sinks, and the cone has a free crater, until a new emission takes place. Such is the ordinary state of the Macaluba ; but from ORIGIN OF MUD VOLCANOES. 95 time to time the hill becomes subject to alarming convul- sions. Slight earthquake shocks are felt at the distance of two or three miles, accompanied with internal noises re- sembling thunder. These increase for several days, and are followed at last by a prodigious spout of mud, earth, and stones, which rises two or three hundred feet in the air. Similar paroxysmal explosions have been observed in the Caucaisian mud volcanoes. In February 1794, the Obu, in the peninsula of Taman, had an eruption accompanied with a dreadful noise, and an earthquake which radiated from the cone, and was felt as far as Ekaterinodor, at a distance of fifty-five leagues. At the beginning of the eruption flames were seen, which rose to a prodigious height, and lasted about half an hour. At the same time dense clouds of smoke escaped from the crater, and mud and stones were cast up to the height of 3,000 feet. Six streams of mud, the largest of which was half a mile long, flowed from the volcano, and their volume is said to have been equal to twenty -two millions of cubic feet. Violent eruptive symptoms accompanied the formation of a new mud volcano in the vicinity of Baku on the Caspian. On November 27, 1827, flames blazed up to an extraordinary height for three hours, and continued for twenty hours more to rise about three feet above a crater from which mud was ejected. At another point in the same district, where flames issued, fragments of rock, of large size, were hurled up into the air and scattered around. The phenomena exhibited by the Macaluba and other mud cauldrons are certainly very distinct from those of true vol- canoes, since no scoriae or lava or heated matters of any kind are sent forth, the mud being described as cold when emitted, although the gas, whose violent escape throws it up, is sometimes ignited. Hence geologists commonly regard these phenomena as entirely distinct from the volcanic, and ascribe their origin to chemical action going on at no great depth beneath the surface, among the constituents of certain stratified matters ; while other scientific authorities declare them to be as much connected with internal igneous agency as any other eruptive phenomena. Their occurrence in dis- 96 THE SUBTERRANEAN WORLD. tricts not remote from tlie sites of vast volcanic disturbance^ and their occasional violent paroxysms, certainly afford much support to this view, and show that it is probably the same power, in different degrees of energy, which casts up the mud of the Macaluba and pours forth the lava-streams of Cotopaxi. 97 CHAPTEE IX. EARTHQUAKES. Extent of Misery inflicted by great Earthquakes — Earthquake Eegions — Earth- quakes in England — Great Number of Earthquakes — Vertical and undulatory Shocks — "Warnings of Earthquakes — Sounds attending Earthquakes — Remark- able Displacements of Objects — Extent and Force of Seismic Wave Motion — Effects of Earthquakes on the Sea — Enormous Waves on Coasts — Oscillations of the Ocean — Pissures, Landslips, and shattering Falls of Eock caused by Earth- quakes —Causes of Earthquakes — Probable Depth of Focus — Opinions of Sir Charles Lyell and Mr. Poulett Scrope — Impressions produced on Man and Animals by Earthquakes. OF all the destructive agencies of nature there is none to equal the earthquake. The hurricane is comparatively- weak in its fury ; the volcanic eruption generally confines its rage to the neighbourhood of the labouring mountain, but a great earthquake may cover a whole land vrith ruins. The terrible subterranean revolution which convulsed all Asia Minor and Syria in the reign of Tiberius, destroyed twelve celebrated cities in a single night. The sun, which on setting had gilded their temples and palaces with his parting rays, beheld them prostrate on the following morning. In A.D. 115 Antioch was the centre of a great commotion. The city was fuU of soldiers under Trajan ; heavy thunder, excessive winds, and subterranean noises were heard ; the earth shook, the houses fell ; the cries of people buried in the ruins passed unheeded. The Emperor leaped from a window, while mountains were broken and thrown down, and rivers disappeared, and were replaced by others in a new situation. Pour centuries later (May 20, 626) the same doomed city was totally subverted by an earthquake, when it is reported that 250,000 persons perished. Similar catastrophes, in which thousands and thousands of victims were suddenly destroyed, have frequently occurred in 08 THE SUBTERRANEAN WOKLD. Peru and Chili, in the West Indies and Central America, in the Moluccas and Java, in the countries bordering on the Mediterranean and the E.ed Sea ; but a bare mention of the loss of life conveys but a faint idea of the extent of misery- inflicted by one of those great earthquakes which mark with an ominous shade many large tracts of the earth's surface. We must picture to ourselves the slow lingering death which is the fate of many — some buried alive, others burnt in the fire which almost invariably bursts out in a city where hundreds of dwellings have suddenly been laid prostrate — the numbers who escaped with loss of limbs or serious bodily injuries, and the surviving multitude, suddenly reduced to penury and want. In the Calabrian earthquake of 1783, it is supposed that about a fourth part of the inhabitants of Polistena and of some other towns were bm'ied alive, and might have been saved had there been no want of hands ; but in so general a calamity, where each was occupied with his own misfor- tunes or those of his family, help could seldom be procured. ' It frequently happened,' says Sir Charles Lyell, ' that persons in search of those most dear to them could hear their moans, could recognise their voices, were certain of the exact spot where they lay buried beneath their feet, yet could afford them no succour. The piled mass resisted all their strength, and rendered their efforts of no avail. At Terranuova four Augustin monks, who had taken refuge in a vaulted sacristy, the arch of which continued to support a vast pile of ruins, made their cries heard for the space of four days. One only of the brethren of the whole convent was saved, and of what avail was his strength to remove the enormous weight of rubbish which had overwhelmed his companions ? He heard their voices die away gradually, and when afterwards their four corpses were disinterred, they were found clasped in each other's arms. Affecting narratives are preserved of mothers saved after the fifth, sixth, and even seventh day of their interment, when their infants or children had perished with hunger. In his work on the great Neapolitan earthquake of 1857, Mr. Mallet, from innumerable narratives of personal peril and sad adventure, selects the distressing case of a noble family MORAL EFFECTS OF EARTHQUAKES. 99 of Monte Murro, as affording a vivid picture of the terrors of an earthquake night. Don Andrea del Fino, the owner of one of the few houses in the city which escaped total de- struction, was with his wife in bed, his daughter sleeping in an adjacent chamber on the principal floor. At the iirst shock his wife, who was awake, leaped from bed, and imme- diately after, a mass of the vaulting above came down, and buried her sleeping husband. At the same moment, the vault above their daughter's room fell in upon her. From the light and hollow construction of the vaults neither was at once killed. The signora escaped by leaping from the front window, she scarcely knew how. For more than two hours she wandered, unnoticed, amongst the mass of terrified sur- vivors in the streets, before she could obtain aid from her own tenants and dependants, to extricate her husband. They got him out after more than eighteen hours' en- tombment — alive, indeed, but maimed and lame for life. His daughter was dead. As he lay longing despairingly for release from the rubbish, which a second shock, an hour after the first, had so shaken and closed in around him that he could scarcely breathe, he heard, but a few feet off, her agonising cries and groans grow fainter and fainter, until at last they died away. His wife, to whose devotion his own life was owing, had escaped Unhurt. Unfortunately man too often vies with the brute forces of nature to increase the horrors of a great earthquake. As the arm of the law is paralysed by the general panic, thieves and ruffians are not slow to avail themselves of their oppor- tunity. Thus in the Calabrian catastrophe of 1783, nothing could be more atrocious than the conduct of the peasants, who abandoned the farms and flocked in great numbers into the towns — not to rescue their countrymen from a lingering death, but to plunder. They dashed through the streets amid tottering walls and clouds of dust, trampling beneath their feet the bodies of the wounded and half buried, and often stripping them, while yet living, of their clothes. From the vast ruin and misery they entail, it is evident that where earthquakes are frequent, there can never be perfect security of property even under the best government ; and as the fruits collected by the labour of many years may H 2 100 THE SUBTERRANEAN WORLD. be lost in an instant, the progress of civilisation and national wealth must necessarily be retarded. ' Earthquakes alone,' says Mr. Darwin, ' are sufficient to destroy the prosperity of any country. If beneath England the now inert subterranean forces should exert those powers which most assuredly in former geological ages they have exerted, how completely would the entire condition of the land be changed ! What would become of the lofty houses, thickly packed cities, great manufactories, the beautiful public and private edifices ? If the new period of disturbance were first to commence by some great earthquake in the dead of the night, how terrific would be the carnage ! England would at once be bankrupt ; all papers, records, and accounts would from that moment be lost. Government, being unable to collect the taxes, and failing to maintain its authority, the hand of violence and rapine would remain uncontrolled. In every large town famine would go forth, pestilence and death following in its train.' Fortunately the experience of many ages shows that the regions subject to these terrible catastrophes are confined to a comparatively small part of the surface of the globe. Thus Southern Italy and Sicily ; the tract embracing the Canaries, the Azores, Portugal, and Morocco ; Asia Minor, Syria, and the Caucasus ; the Arabian shore of the Red Sea ; the East Indian Archipelago ; the West Indies, Nicaragua, Quito, Peru, and Chili, are particularly liable to destructive shocks. But beyond these limits slighter earthquakes are of far more common occurrence than is generally supposed, and probably they leave no part of the world entirely undisturbed. From the year 1821 to 1830 no less than 115 earthquakes have been felt to the north of the Alps, and since the year 1089, 225 are cited in the annals of England. Some of these earthquakes seem to have but just stopped at the point when a slight increase of their force would have covered the land with ruins. In 1674, on the 26th of February, between five and six in the evening, an earthquake was felt at York, Worcester, Hereford, Gloucester, and Bristol. Norton Chapel was filled with worshippers ; they were nearly all overthrown, and fled in terror, thinking that the dead were unearthed or DURATION OF EARTHQUAEES. jOi that tlie chapel was falling. Six years later, on the 6th of April, at 6 p.m., all England was thrown into consternation. The great beU at Westminster began to toll ; the students at the Temple started up from table and rushed into the street, knives in hand; a part of the Temple Church fell, and stones dropped from St. Paul's. Two stones fell in Christ's Church, and crushed two persons. In rushing out of the church many were lamed, and there was a shower of chimneys in the streets. At Sandwich, the occurrence was marked by the violence of the sea, which made ships run foul of each other ; and at Dover a part of the fortifica- tions fell with the rock which supported it. On the 6th October 1863, a movement, though gentle when compared to the preceding instances, was felt from the English Channel to the Mersey, and from Hereford to Leamington and Oxford. The Malvern range was about the centre of the area, as it has often been before. Even in alluvial Holland, six or eight slight earthquakes have been felt during the last century. The industrious researches of Kluge show that, during the eight years from 1850 to 1867, no less than 4,620 earthquakes — a gTcat proportion of which (609) fell to the share of Southern Europe — have been noticed in both hemispheres ; and when we remember that a very considerable part of the globe is still either totally unknown or removed by the barbarous condition of its inhabitants from all intercourse with the scientific world, and that, con- sequently, the above list must necessarily be incomplete, it is very probable that not a day passes without some agitation of the surface of the earth in some place or other. A violent earthquake almost always consists of several shocks following each other in rapid succession. Sometimes they are preceded by slighter vibrations ; at other times they suddenly convulse the land without any previous notice. In most instances, each shock lasts but a few seconds ; but this is enough to ruiii the work of ages. Three violent com- motions within five minutes destroyed the town of Caraccas on March 26, 1812; and the earthquake which, in 1692, desolated Jamaica lasted but three minutes. On January 11, 1839, two shocks within thirty seconds covered Marti- nique, and the whole range of the Lesser Antilles, with ruins. 102 THE SUBTEKKANEAN WORLD. But a violent earthquake, tliougli itself but of short duration, is generally followed by a series of secondary shocks, which are repeated at gradually widening intervals and with de- creasing energy, so that if these subsequent tremors be taken into account, it may often be said to last for weeks, or even months. Thus, to cite but one instance, the earthquake of October 21, 1766, destroyed the whole town of Cumana ia a few minutes, but during the following fourteen months the earth was in a constant vibratory motion, and scarce an hour passed without a shock being felt. In countries where earthquakes are comparatively rare (for instance in the south of Europe) the belief is very general that oppressive heat, stillness of the air, and a misty horizon are always forerunners of the phenomenon. But this popular opinion is not confirmed by the experience of trust- worthy observers, who have lived for years in countries such as Cumana, Quito, Peru, and Chili, where the ground trembles frequently and violently. Humboldt experienced earthquakes during every state of the weather, serene and dry, rainy and stormy. Brute animals, being more sensitive than men of the slightest movement of the earth, are said to evince extra- ordinary alarm, and it has been often observed that even the dull hog shows symptoms of uneasiness previous to the shock. During the great Neapolitan earthquake of 1857 an unusual halo-like light was seen in the sky before, and not long before, the shock. Mr. Mallet was at first inclined to look upon this notion as a superstitious tale ; but, finding it widely diffused in a country where communication is bad and news travels slowly, no longer doubted that it was founded on fact.* Conjectures would be useless as to its nature, but future observation directed to the point may determine whether some sort of auroral light may emanate from the vast depths of rock formation under the enormous tensions and compressions that must precede the final crash and rupture; or whether volcanic action, going on in the unseen depths below, may give rise to powerful disturbances of electric equilibrium, and hence to the development of * Mallet, ' The Great Neapolitan Earthquake of 1857,' vol. i. p. 323. SOUNDS IN EARTHQUAKES. 103 light ; just as from volcanic mountains in eruption light- nings continually flash from the huge volumes of steam and floating ashes above the crater, Humboldt is also of opinion that, though in general the revolutions which take place below the surface of the earth are not announced beforehand by any meteorological process, or a peculiar appearance of the sky, it is not improbable that during violent shocks some change may occur in the condition of the atmosphere. Thus, during the earthquake in the Piedmontese valleys of Pelis and Clusson, great alterations were observed in the electrical tension of the atmosphere without any appearance of a thunder-storm. Earthquakes are generally attended with sounds, some- times like the howling of a storm, or the rumbling of sub- terranean thunder, at others like the clashing of iron chains, or as if a number of heavily laden waggons were rolling rapidly over the pavement, or as if enormous masses of glass were suddenly shivered to pieces. As solid bodies are excel- lent conductors of sound (burnt clay, for instance, propa- gating it ten or twelve times more rapidly than the air), the subterranean noise may be heard at a vast distance from the primary seat of the earthquake. In Caraccas, in the grass- plains of Calabozo, and on the banks of the Rio Apure, which falls into the Orinoco, a dreadful thunder-like sound was everywhere heard on April 30, 1812, without any simul- taneous trembling of the earth, at the time when, at the distance of 168 geographical miles, the volcano of St. Vin- cent, in the Lesser Antilles, was pouring out of its crater a mighty lava- stream. This was, according to distance, as if an eruption of Vesuvius were heard in the north of Prance. In the year 1744, during the great eruption of the volcano Cotopaxi, a subterranean noise like the firing of cannon was heard at Honda on the Magdalena river. But the crater of Cotopaxi is 17,000 feet higher than Honda, and both points, situated at a distance of 109 geographical miles, are moreover separated by the colossal mountain masses of Quito, Pasto, and Popayan, and by numberless ravines and deep valleys. The sound was certainly transmitted, not through the air, but through the earth, and must have pro- ceeded from a very considerable depth. 104 THE SUBTERRANEAN WORLD. But noise is not the necessary attendant of an earthquake, for many instances are known in wliich the most violent shocks have been completely noiseless. No subterranean sounds were heard during the terrific earthquake which de- stroyed Eiobamba on February 4, 1797, and the same circum- stance is mentioned in the nan-atives of many of the Chilian earthquakes. The phenomenon of sound, when unaccompanied by any perceptible vibration, makes a peculiarly deep impression on the mind, even of those who have long inhabited a country subject to frequent earthquakes. They tremble at the idea of the catastrophe which may foUow. A remarkable instance of a long protracted noise without any trembling of the earth occurred in 1784, at the wealthy mining town of Guanaxuato in Mexico, where the rolling of subterranean thunder, with now and then a louder crash, was heard for more than a month, without the slightest shock, either on the surface of the earth, or in the neighbouring silver mines, which are 1,600 feet deep. The noise was confined to a small space, so that a few miles from the town it was no longer audible. Never before had this phenomenon been known to occur in the Mexican highlands, nor has it been repeated since. Earthquake shocks are either vertical or undulatory. A vertical shock, which is felt immediately above the seat or focus of the subterranean disturbance, causes a movement up and down. Like an exploding mine, it frequently jerks movable bodies high up into the air. Thus, during the greab earthquake of Eiobamba, the bodies of many of the inhabitants were thrown upon the hill of La CuUa, which rises to the height of several himdred feet at the other side of the Lican torrent ; and during the earthquake of Chili in 1837, a large mast, planted thirty feet deep in the ground at Fort San Carlos, and propped with iron bars, was thrown upwards, so that a round hole remained behind. Although to the inhabitants of a shaken district the undulatory wave or vibration of an earthquake appears to radiate horizontally outwards from the spot on the surface where it is first felt, the force does not really operate in a horizontal direction, like a wave caused by a pebble on the WAVE-MOTION OF EARTHQUAKES. 105 surface of a pond ; for at every point, except that immediately above tlie focus of tlie shock, it comes up obliquely from below, causing the ground to move forwards and then back- wards in a more or less horizontal direction. As a ship, yieldiQg to the oscillatory movements of the waves, alter- nately inclines to one side or the other, so, during the more violent undulations of the soil, the objects on its surface are momentarily moved from their vertical position, and often considerably inclined towards the horizon. Thus during the great earthquake which convulsed the valley of the Missis- sipi in 1811-12, Mr. Bringier, an engineer of New Orleans, who was on horseback near New Madrid, where some of the severest shocks were experienced, saw the trees bend as the wave-motion of the earthquake passed under them, and immediately afterwards recover their position. The transit of the wave through the woods was marked by the crash of countless branches, first heard on one side and then on the other. It must have been awful to see the giants of the forest thus move to and fro like a corn-field agitated by the wind ! Very remarkable displacements of objects are not seldom caused by earthquakes, such as the rotation of the blocks of columns or the turning of statues on their pedestals. At Lima, which, owing to its repeated destructions by earthquakes, is properly a city of ruins. Professor Dana saw two obelisks with the upper stone on each displaced and turned round on its axis about fifteen degrees in a direction from north to east. These rotations by earthquakes have been attributed by some authors to an actual rotatory movement in the earthquake vibration; but it has lately been shown by Mr. Mallet that this hypothesis is untenable and unnecessary, as a simple vibration back and forth is all that is required to produce a rotatory motion in the stone of a column, provided that stone be attached below more strongly on one side of the centre than on the opposite. The wave-motion of an earthquake sometimes spreads over enormous spaces. The shocks of the earthquake of New Granada which took place in the night from the 16th to the 17th of June 1826, were noticed over a surface of 750,000 square miles. The earthquake of Yaldivia (February 20, 106 THE SUBTEEKAJ^'EAN WORLD. 1835) was felt southwards on tlie distant island of CMloe to tlie north as far as Copiapo, in Mendoza to the east of the Andes, and on the Island of Juan Fernandez, 300 miles from the coast. Supposing these effects to have taken place at corresponding distances in Europe, all the land would have trembled from the North Sea to the Mediter- ranean, and from. Ireland to the centre of France. It is evident that the extent and force of the wave-motion of an earthquake must in a great measure depend upon the nature of the rocks through which it is transmitted. It will vibrate more easily through solid homogeneous masses, while in alluvial deposits, or in a soil composed of sand and loose conglomerate, its undulations will be propagated irregularly and its effects be far more destructive. This is particularly the case where the alluvial deposits repose on a substratum of hard rock. Thus the devastations of the Calabrian earth- quake of 1783 were most apparent in the plain of Oppido, in those parts where the newer tertiary strata rest upon granite. The earthquake wave generally follows the direction of mountain-chains, and but rarely crosses them. The great Chilian earthquakes, which often propagate their vibrations to distances of many hundred miles along the western foot of the Andes, remain unfelt on their eastern border ; while the earthquakes along the shores of Venezuela, Caraccas, and New Granada rarely transmit their vibrations beyond the high mountain-chains which run parallel with the coast. This is probably due to the numerous dislocations, rents, and caverns which are produced by the elevation of the mountain- chains, and necessarily serve as barriers to the propagation of the earthquake wave. Severe earthquakes are not seldom accompanied by a violent agitation of the sea. First, at the instant of the shock, the water swells high up on the beach with a gentle motion, and then as quietly recedes; secondly, some time afterwards, the whole body of the sea retires from the coast, and then returns in waves of overwhelming force. The first movement seems to be an immediate consequence of the earthquake affecting differently a fluid and a solid, so that their respective levels are slightly deranged ; but the second is a far more important phenomenon. ' Some authors,' says MOVEMENTS OF THE SEA IN EARTHQUAKES. 107 Mr. Darwin, ' have attempted to explain it by supposing that the sea retains its level, while the land oscillates upwards ; but surely the water close to the land, even on a rather steep coast, would partake of the motion of the bottom; more- over, similar movements of the sea have occurred at islands far distant from the chief line of disturbance. I suspect (but the subject is a very obscure one) that a wave, however produced, first draws the water from the shore on which it is advancing to break. I have observed that this happens with the little waves from the paddles of a steamboat. From the great wave not immediately following the earthquake, but sometimes after the interval of even half-an-hour, and from distant islands being affected similarly with the coasts near the focus of the disturbance, it appears that the wave first rises in the offing, and, as this is of general occurrence, the cause must be general. I suspect we must look to the line where the less disturbed waters of the deep ocean join the water nearer the coast which has partaken of the movements of the land, as the place where the great wave is first generated ; it would also appear that the wave is larger or smaller according to the extent of shoal water which has been agitated together with the bottom on which it rested.' The following examples sufficiently prove that no storm, however violent, is capable of raising such prodigious waves as an earthquake. In the year 1692 the town of Kingston in Jamaica was almost totally destroyed by a huge earthquake wave. A frigate which lay in port was carried forwards over the houses and stranded in the middle of the town. In his 'Principles of Geology,' Sir Charles Lyell relates that, during the Cala- brian earthquake of 1783 the Prince of Scilla had persuaded a great part of his vassals to betake themselves to their fishing boats for safety, and he himself had gone on board. On the night of February 5, when some of the people were sleeping in the boats, and others on a level plain slightly elevated above the sea, the earth rocked and large masses of rock were thrown down with a dreadful crash upon the plain. Immediately afterwards the sea, rising more than twenty feet above the level of this low tract, rolled foaming over it and swept away the multitude. It then retreated, but soon 108 THE SUETEREAXEAN WORLD. rushed back again with greater violence, bringing back with it some of the bodies it had carried away. At the same time every boat was sunk or dashed against the beach, and some of them were swept far inland. The aged prince was killed, with 1,430 of his people. After the earthquake which devastated the town of Lima on the 28th of October 1746, the sea rose on the evening of the same day eighty feet above its usual level in the neighbouring Bay of Callao, overwhelmed the town, and destroyed nearly all the inhabitants. Of the twenty-three ships which were lying in the harbour at the time, nineteen immediately sank, while the four others were thrown upon the land at the distance of nearly a league. Shortly after the shock which desolated Chili on the 20th of February 1836, a great wave was seen from the distance of three or four miles, approaching in the middle of the Bay of Talcahuano with a smooth outline, but tearing up cottages and trees along the shore, as it swept onwards with irresistible force. At the head of the bay it broke in a fearful line of white breakers, which rushed up to a height of twenty-three vertical feet above the highest spring tides. Their force must have been prodigious, for at the Fort a cannon with its carriage, estimated at four tons in weight, was moved fifteen feet inwards. The whole coast was strewed over with timber and furniture, as if a thousand ships had been wrecked. As Mr. Darwin walked along the shore, he observed that nume- rous fragments of rock, which, from the marine productions adhering to them, must recently have been lying in deep water, had been cast up high on the beach. One of these was six feet long, three broad, and two thick. During the dreadful earthquake which in 1868 raised the strip of land at the western foot of the Andes from IbuiTa in Ecuador, to Iquique in Peru, 1,200 miles in length, the receding sea uncovered the bay at Iquique to the depth of four fathoms, and then, returning in an immense wave, a mass of dark blue water, forty feet high, rushed over the already ruined city, and swept away every trace of what had been a town. One spectator, seeing the whole surface of the sea rise like a mountain, ran for his life to the Pampa. The waves over- took him. Fighting with the dark water, amidst wreck and MOTION OF EARTHQUAKE WAVES. 109 ruin of every kind, carried back into the bay, and again thrown back to the Pampa, wounded and half-naked, he crept for safety into a hole of the sand, and waited sadly for the dawn. At Arica, the British Vice-Consul, alarmed at the first shock, rushed out of the house with his family, and made for the high ground, in just terror of the expected sea-wave. Tlirough the ruined town, amidst dead and dying, half stifled with dust, they reached rising ground, and, looking back, saw a dreadful sequel — the sea rushed in and left not a vestage remaining of the lower part of Arica. Six vessels were lost in the bay or tossed over rocks and houses; an American gunboat was whirled away from her moorings, and laid, without a broken spar of tarnished flag, high and dry on the sand-hills, a quarter of a mile from the sea. As might be expected from the movable nature of water, the wave-motion of earthquakes is frequently propagated to surprising distances over the sea. The Chilian earthquake of 1835 produced oscillations of the ocean that made them- selves felt on the Sandwich Islands at a distance of 5,000 nautical miles. On Mauai, the sea retreated 120 feet, and then suddenly returned with a tremendous wave that swept away the trees and houses on the beach. In Hawaii, a large congregation had assembled for divine service near Byron's Bay. Suddenly the water began to sink, so that soon a great part of the harbour was laid dry. The spec- tators hurried to the shore to admire the astonishing spectacle, when a wave, rising twenty feet above the usual tide-mark, inundated the land, destroyed sixty-six huts, and drowned eleven of the islanders, though the best swimmers in the world. So far from its starting-point did the South American earthquake seek its victims. Fifteen hours and a half after the great earthquake of Arica (1868) the water- wave undulating over the vast Pacific was felt at Chatham Islands, a distance of 6,300 miles, and an hour later at New Zealand. The enormous powers which come into action during a great earthquake show themselves not only in the destruc- tion of edifices and the wide-spread ruin so produced, but in the changes which they effect in the configura- tion of the soil. Wherever masses of earth rest loosely no THE SUBTERRANEAN WORLD. upon a sloped surface of subjacent rock, or where steep mountain crests overlie wet and unctuous beds of shale, or where the rock itself is composed of coherent material, or where river-banks are formed of precipitous masses of clays, or where the corroding waters have undermined the ground, the violent commotion caused by an earthquake cannot fail to produce landslips, fissures, and falls of rock. In 1571, on the 17th of February, the ground opened all at once at the ' Wonder,' near Putley, not far from Marcle in Hereford- shire ; and a large part of the sloping surface of the hill — twenty-six acres, it is said — descended with the trees and sheep-folds, and continued in motion from Saturday to Monday, masses of ground being turned round through half a circle in their descent. This was a great landslip, said to have been occasioned by an earthquake. Earth-fissures were formerly supposed to be occasioned by a stretching of the ground, occasioned by the wavy nature of the shocks ; but Mr. Mallet has shown that no earthquake wave can possibly produce any such stretching, and con- siders them as eases of small and incipient landslips caused by the shaking downwards of a loose mass. His own observa- tions left no doubt in his mind that the descriptions, given by the Neapolitan Academy in their Historical Account of the Earthquake of 1783, of the earth-fissures therein produced, and designated constantly by the pompous term ' voragines,' are gross exaggerations, and that the well-known Jamaica earth-fissures, that were said to have opened and closed with the wave, and to have bitten people in two, must be regarded as audacious fables. ' The vulgar mind, filled from infancy with superstitious terrors as to " the things under the earth," is seized at once by the notion of these fissures of profound and fabulous depth with fire and vapour of smoke issuing from within their murky abysses ; but they should cease to belong to science.' Enormous landslips are sometimes occasioned by earth- quakes, but their extent depends less upon the power and energy of the shock than upon the conditions of unstable equilibrium presented by great masses of loose material, through the configuration of the country. In consequence of landslips or dislodgements of large masses of rock, altera- CAUSES OF EARTHQUAKES. Ill tions in the flow or distribution of tlie waters frequently take place. Thus, brooks or rivers are not seldom dammed, and temporary ponds or lakes created. Permanent elevations of the land have been observed after some earthquakes. Thus, after the violent shocks of November 19, 1822, a great part of the coast of Chili was found to be raised several feet above its previous level, and after the great earthquake which occurred in New Zealand in the night of January 23, 1856, a large tract of land was found to be permanently upraised from one to nine feet. Before the shock there had been no room to pass between the sea and the base of a perpendicular cliff called Muka- Muka, except for a short time at low water, and the herds- men were obliged to wait for low tide in order to drive their cattle past the cliff. But immediately after the upheaval, a gently sloping raised beach, more than 100 feet wide, was laid dry, affording ample space at all states of the tide for the passage of man and beast. These permanent elevations have often been attributed to the immediate agency of earthquakes ; but Mr. Mallet proves this assumption to be a fallacy, as the impulse of the earth- quake wave even right above the focus is utterly incapable of raising the level of the land by a height much more than in- strumentally appreciable, and there is not the least evidence that any part of even this elevation is permanent. That earthquakes occur along with, and as part of, a train of other circumstances which do produce permanent elevation occasion- ally, and that earthquakes are probably always the signals that the forces producing elevation are operative, is another matter, with which that erroneous or loosely expressed view should not be confounded. The causes of earthquakes are still hidden in obscurity, and probably will ever remain so, as these violent convulsions originate at depths far below the reach of human observation. Mr. Mallet came to the conclusion that the depth of the original Calabrian shock in 1857 did not exceed seven or eight miles, and deduces from all the facts known as to the movements of earthquakes, that the subterranean points where the shocks originate perhaps never exceed thirty geographical miles, so that, even supposing the central 112 THE SUBTERRANEAN WORLD. nucleus of the earth to be fluid, they cannot possibly be due to the reaction of the internal ocean of molten stone upon the solid shell with which it is enveloped, but must have their seat within the latter. The existence of reservoirs of fused matter at various depths in the solid earth-rind is quite sufficient to account for all seismic and volcanic phenomena ; for it is evident that whenever rain-water, or the waters of the sea percolating through rocks, gain access to these subter- ranean lakes of molten stone, steam must be generated, the pressure of which will in many cases rend and dislocate the incumbent masses. ' During such movements,' says Sir Charles Lyell, ' fissures may be formed and injected with gaseous or fluid matter, which may sometimes fail to reach the surface, while at other times it may be expelled through volcanic vents, stufas, and hot springs. When the strain on the rocks has caused them to split, or the roofs of pre-existing fissures or caverns have been made to fall in, vibratory jars will be produced and propagated in all directions, like waves of sound through the crust of the earth, with varying velocity, according to the violence of the original shook, and the density or elasticity of the substance through which they pass. They will travel, for example, faster through granite than through limestone, and more rapidly through the latter than through wet clay, but the rate will be uniform through the same homogeneous medium.' According to Mr. Poulett Scrope, the originating cause of the earthquake must be sought in the expansion of some deeply seated mass of mineral matter, owing to augmentation of temperature or diminution of pressure. By this expansive force, the solid rocks above are suddenly rent asunder, and whether below the sea or not, their violent disruption pro- duces a jarring vibration, which is propagated on either side through their continuous masses in undulatory pulsations. Some geologists are of opinion that earthquakes are fre- quently the result of the subsiding, sinking in, or cracking of subterranean cavern roofs, in consequence of the pressure of the superincumbent rocks. Small local earthquakes may be explained by this theory; but terrible convulsions which shake a whole continent evidently proceed from a far more EARTHQUAKES IN PERU. 113 formidable cause, and are more satisfactorily explained by the agency of subterranean heat and elastic vapours. If, even during an ordinary storm, the black clouds, the howling of the wind, the flashes of lightning, and the loud claps of thunder strike men and brutes with fear, we may naturally expect to see terror carried to its highest pitch by so dreadful a phenomenon as an earthquake. All creatures living or burrowing under the earth — rats, mice, moles, snakes — hastily creep forth from their subterranean abodes, though many no doubt are gripped and suffocated by the suddenly moved soil before they can effect their escape ; the crocodile, generally silent, like our little lizards, rushes out of the river and runs bellowing into the woods ; the hogs show symptoms of uneasiness ; the horses tremble ; the oxen huddle together ; and the fowls run about with discordant cries. On man, the phenomenon makes a peculiarly deep impression. ' A bad earthquake,' says Mr. Darwin, ' at once destroys our oldest associations. The earth, the very emblem of solidity, has moved beneath our feet like a thin crust over a fluid. One second of time has created in the mind a strange idea of insecurity, which hours of reflection would not have pro- duced.' We can no longer trust the soil on which we stand, and feel ourselves completely at the mercy of some unknown destructive power, which at any moment, without forewarn- ing, can destroy our property or our lives. But as first impressions are always the deepest, so habit renders man callous even to the terrors of an ordinary earthquake. In countries where slight shocks are of frequent occurrence, almost every vestige of fear vanishes from the minds of the natives, or of the strangers whom a long residence has familiarised with the phenomenon. On the rainless coast of Peru, thunderstorms and hail are unknown. The thunder of the storm is there replaced by the thunder which accompanies the earthquake. But the frequent repetition of this subterranean tumult, and the general belief that dangerous shocks occur only twice or thrice in the course of a century, produce in Lima so great an indifference towards slighter oscillations of the soil that they hardly attract more attention than a hail-storm in Northern Europe. 114 THE SCBTEKRANEAN WORLD. CHAPTEE X. THE GEBAT BAETHQUAKE OP LISBON. A dreadful All Saints' Day — The Victims of a Minute — Report of an Eye-witness ■ — Conflagration — Banditti — Pombal brings Order into Chaos — Intrigues of the Jesuits — Damages caused by the Earthquake in other Places — at Cadiz — in Barbary — Widespread Alarm — ^Remarks of Goethe on the Earthquake. HISTORY exhibits few catastroplies more terrible than that which wafe caused by the great earthquake which, on November 1, 1755, levelled the town of Lisbon to the dust. .On other occasions, such as that of, a siege, a famine, or a plague, calamity approaches by degrees, giving its victims time to measure its growth, and preparing them, as it were, to sustain an increasing weight of misery ; but here destruction fell upon the devoted city with the rapidity of a flash of lightning. A bright sun shone over Lisbon on that fatal morning. The weather was as mild and beautiful as on a fine summer's day in England, when, about forty minutes past nine, in the morning, an earthquake shock, followed almost immediately by another and another, brought down convents, churches, palaces, and houses in one common rain, and, at a very moderate computation, occasioned the loss of thirty thousand lives. ' The shocking sight of the dead bodies,' says an eye- witness of the scene, ' together with the shrieks and cries of those who were half buried in the ruins, exceeds all descrip- tion ; for the fear and consternation were so great that the most resolute person durst not stay a moment to remove a few stones off the friend he loved most, though many might have been saved by so doing ; but nothing was though.t of but self-preservation. Getting into open places, and into the middle of streets, was the most probable security. Such as were in the upper storeys of houses were, in general, more DESTKUCTION OF LISBON. 155 fortunate than those who attempted to escape by the doors ; for they were buried under the ruins with the greatest part of the foot-passengers ; such as were in equipages escaped best, though their cattle and drivers suffered severely ; but those lost in houses and the streets are very unequal in number to those that were buried in the ruins of churches ; for as it was a day of great devotion, and the time of cele- brating mass, all the churches in the city were vastly crowded; and the number of churches here exceeds that of both London and Westminster ; and as the steeples are built high, they mostly fell with the roof of the church, and the stones are so large that few escaped.' * Many of those who were not crushed or disabled by the falling buildings fled to the Tagus, vainly hoping that they might find there the safety which they had lost on land. For, soon after the shock, the sea also came rushing in like a torrent, though against wind and tide, and rising in an enormous wave, overflowed its banks, devouring all it met on its destructive path. Many large vessels sank at once ; others, torn from their anchors, disappeared in the vortex, or, striking against each other, were shattered to pieces. A fine new stone quay, where about three thousand persons had assembled for safety, slipped into the river, and every one was lost ; nor did so much as a single body appear after- wards. Had the misery ended here, it might in some degree have admitted of redress ; for, though lives could not be restored, yet a great part of the immense riches that were in the ruins might have been recovered; but a new calamity soon put an end to such hopes, for, in about two hours after the shock, fires broke out in three different parts of the city, caused by the goods and the kitchen fires being all jumbled together. About this time also, a fresh gale suddenly spring- ing up, made the fire rage with such violence that, at the end of three days, the greatest part of the city was reduced to ashes. What the earthquake had spared fell a prey to the fire, and the flames consumed thousands of mutilated victims, who, incapable of flight, lay half-buried in the ruins. According to a popular report, which, true or not, shows * Philosophical Transactions, vol. xlix. part i. p. 404. I 2 U6 THE SUBTERRANEAN WORLD. the hatred in which the Holy Office was held, the Inqtiisitioni was the first building that fell down, and probably more than one inquisitor, who, in his life-time, had sent scores of Jews or heretics to the stake, was now, in his turn, burnt alive. As if the unshackled elements were not sufficient agents of destruction, the prisons also cast forth their lawless denizens, and a host of malefactors, rejoicing in the public calamity which paralysed the arm of justice, added rapine and murder to the miseries of the city. More than 60,000 persons are supposed to have perished in Lisbon from all these various causes. The total loss of property was estimated at fifty millions of dollars, an enor- mous sum for a small country, and in times when money was far more valuable than at present. A few shocks suf- ficed to destroy the treasures accumulated by the savings of many generations. The royal family was at this time residing in the small palace of Belem, about a league out of town, and thus escaped being buried among the ruins of the capital — a fortunate occurrence in the midst of so many misfortunes ; for the anarchy that must have ensued from the destruction of all authority would have filled the cup of misery to the brim. As it was. Government seemed utterly incapable of contending with a disaster of such colossal proportions. ' What is to be done ? ' said the helpless king to his minister Carvalho, Marquis of Pombal, who, on entering the council- chamber, found his sovereign vainly seeking for advice among his weeping and irresolute courtiers : ' how can we alleviate the chastisement which Divine justice has imposed upon us ? ' ' Sire ! by burying the dead and taking care of the living,' was the ready answer of the great statesman, whose noble bearing and confident mien at once restored the king's courage. From that moment Jose bestowed a boundless confidence upon Pombal. Without losing a single moment, the minister, invested with full powers, threw him- self into a carriage, and hastened with all speed to the scene of destruction. Wherever his presence was most needed, there was he sure to be found. Por several days and nights he never left his carriage, whence, incessantly active in his efforts to reduce chaos to order, he issued no less than two EARTffQUAKE AT CADIZ. 117 hundred decrees, all bearing the stamp of a master-raind^ Troops from the provinces were summoned in all haste, and concentrated round the capital, which no one was allowed to leave without permission, so that the robbers, who had en- riched themselves with the plunder of palaces and churches, were unable to escape with their spoils. In all his numerous ordinances Carvalho neglected none of the details necessary for insuring their practical utility, writing many of them on his knees with a pencil, and send- ing them, without loss of time, to the various officers charged with their execution. His wise regulations for ensuring a speedy supply and a regular distribution of provisions averted famine. Great fears were entertained of pestilential disorder's, in consequence of the putrid exhalations of so many corpses, which it was impossible to bury. To prevent this additional misfortune, Carvalho induced the Patriarch to give orders that the bodies of the dead should be cast into the sea, with only such religious ceremonies as circumstances permitted. But the Jesuits, the mortal enemies of the enlightened minister, did not lose this opportunity of intriguing against him, and openly ascribed the catastrophe to the wrath of God against an impious Government. Thus Pombal had not only to cope with the disastrous effects of the earthquake, but also with the venomous attacks of hypocritical bigots, in spite of whose clamours he interdicted all public pro- cessions and devotional exercises that were calculated still further to inflame the excited minds of the populace. Though Lisbon was the chief sufferer from the great earthquake of 1755, the shocks which destroyed the capital of Portugal proved disastrous in many other places, and vibrated far and wide over a considerable portion of the globe. St. TJbes was nearly swallowed up by the sudden rising of the sea. At Cadiz the shocks were so violent that 'the water in the cisterns washed backwards and forwards so as to make a. great froth upon it. No damage was done, on account of the excessive strength of the buildings ; but, about an hour after, an immense wave, at least 60 feet higher than common, was seen approaching from the sea. It broke against the west part of the town, which is very rocky, and 1J8 THE SUBTERRANEAN WORLD. . where, fortunately, the cliffs abated a great deal of its force. At last it burst upon the walls, destroyed part of the for- tifications, and swept away huge pieces of cannon. The strong causeway which connects the town with the Island of Leon, was utterly destroyed, and more than fifty people drowned that were on it at the time. In Seville a number of houses were thrown down, and the bells were set a-ringing in Malaga. In Italy, Germany, and Trance, in Holland and in Sweden, in Great Britain and in Ireland, the lakes and rivers were violently agitated. The water in Loch Lomond rose suddenly and violently against its banks, so that a large stone lying at some distance from the shore, in shallow water, was moved from its place, and carried to dry land, leaving a deep furrow in the ground along which it had moved. At Kinsale, in Ireland, a great body of water suddenly burst into the harbour, and with such violence that it broke the cables of two vessels, each moored with two anchors, and of several boats which lay near the town. The vessels were whirled round several times by an eddy formed in the water, and then hurried back again with the same rapidity as before. London was shaken, the midland counties disturbed, and one high cliff in Yorkshire threw down its half-separated rocks. At Toplitz, in Bohemia, between eleven and twelve o'clock, the mineral waters increased so much in quantity that all the baths ran over. About half an hour before, the spring grew turbid and flowed muddy, and, having stopped entirely for nearly a minute, broke forth again with prodigious violence, driving before it a considerable quantity of reddish ochre. After this, it became clear, and flowed as pure as before, but sup- plying more water than usual, and that hotter and more impregnated with its medicinal substances. In Barbary, the earthquake was felt nearly as severely as in Portugal. Great part of the city of Algiers was destroyed; at Fez, Mequinez, and Morocco many houses were thrown down, and numbers of persons were buried in the ruins. At Tangiers and Sallee the waters rushed into the streets with great violence, and when they retired they left behind them a great quantity of fish. Ships sailing on the distant Atlantic received such violent EFFECTS OF THE LISBON EARTHQUAKE. 119 concussions tliat it seemed as if they had struck upon a rock, and even America was disturbed. At the Island of Antigua the sea rose to such a height as had never been known before, and at Barbadoes a tremen- dous wave overflowed the wharfs and rushed into the streets. The remote Canadian lakes were seen to ebb and flow in an extraordinary manner, and the Eed Indian hunter felt the last expiring pulsations of the great terrestrial shock which a few hours before had overthrown the distant capital of Portugal. Such were the extraordinary efifects of this terrible earth- quake, which extended over a space of not less than four millions of square miles ! Of the enormous sensation it produced over all Europe, as well as of the deep impression it made upon his own youthful mind, Goethe, then about six years old, has given us a masterly account in his autobio- graphy (' Dichtung und Wahrheit '). ' For the first time,' says the illustrious poet, ' the boy's peace of mind was disturbed by an extraordinary event. On ISTovember 1, 1755, the earthquake of Lisbon took place, and spread consternation over a world which had long been accustomed to tranquillity and peace. A large and splendid capital, the seat of wealth and commerce, suddenly falls a prey to the most terrible disaster. The earth shakes, the sea rises, ships are dashed against each other, houses, churches, and tow6rs fall in; the king's palace is partly engulfed by the waves ; the bursting earth seems to vomit flames, for smoke and fire appear everywhere among the rains. Sixty thousand persons, but a moment before in the enjoyment of a comfortable existence, are swept away, and they are the most fortunate who no longer feel or remember their misery. The flames continue to rage, along with a host of criminals whom the catastrophe has set at liberty. The unfortunate survivors are exposed to robbery, to murder, to every act of violence ; and thus on all sides Nature re- places law by the reign of unfettered anarchy. Swifter than the news could travel, the effects of the earthquake had already spread over a wide extent of land ; in many places slighter commotions had been felt; mineral springs had suddenly ceased to flow; and all these circumstances increased 120 THE SUBTERKANEAN WOELD. the general alarm when the terrible details of the catastrophe became known. The pious were now not sparing of moral reflexions, the philosophers of consolations, the clergy of admonitions, Thns the attention of the world was for some time concentrated upon this single topic, and the public, excited by the misfortunes of strangers, began to feel an increasing anxiety for its personal safety, as from all sides intelligence came pouring in of the widely-extended effects of the earthquake. The demon of fear has indeed, perhaps, never spread terror so rapidly and so powerfully over the earth. The boy who heard the subject frequently discussed was not a little perplexed. God, the Creator and Preserver of Heaven and Earth, whom the first article of faith repre- sented as supremely wise and merciful, appeared by no means paternal while thus enveloping the just and the un- just in indiscriminate ruin. It was in vain that his youthful mind endeavoured to shake off these impressions, nor can this be wondered at, as even the wise and the learned did not agree in their opinions on the subject.' 121 CHAPTER XI. LANDSLIPS. Igneous and Aqueous Causes of Landslips — Tall of the Diablerets in 1714 and 1749 — Escape of a Peasant from his living Tomb — Vitaliano Donati on the Fall of a Mountain near Sallenches — The Destruction of Goldau in 1806 — ^Wonderful Preservation of a Child— Burial of Velleja and Tairretunum, of Pliirs and Scilano — Landslip near Axmouth in Dorsetshire — Falling in of Cavern-roofs — DoUinas and Jamas in Carniola and Dalmatia — Bursting of Bogs — Crateriform Hollows in the Eifel. LA2*rDSLIPS, or sudden subsidences and displacements of portions of land, result botli from igneous and aqueous causes. Wherever cavities have been formed beneath the surface of the earth, v^hether in consequence of volcanic eruptions or by the erosive and dissolving Rction of subterranean waters, the shock of an earthquake or the mere weight of the super- incumbent mass may cause the roof to fall in, or the super- ficial ground, no longer sustained by its undermiued foun- dations, to slide away and sink to a lower level. In mountainous regions it frequently occurs that the foundations of a rock, undermined by filtering waters, give way, and that huge masses of stone and earth, now no longer reposing on a solid basis, are precipitated into the valley below. More than once, the slipping or falling in of a moun- tain has brought death and destruction upon the humble dwellings of the Alpine peasants, and added many a mourn- ful page to their simple aimals. Thus, in the years 1714 and 1749, large beds of stone were detached from the Diablerets, a mountain stock between the cantons of Vaux and Valais, and burying the meadows of Cheville and Leytron under-a mound of rubbish 300 feet deep, killed many herds and shepherds. In the first of these catastrophes, the life of a peasant was lL>2 THE SUBTEKKANEAN WORLD. preserved in a wonderful manner. An immense block came toppling down close to Hs chalet and covered it like a shield, so as to preserve it from being crushed by the following debris, though piled up two hundred feet above it. Thus, immured as it were in a living tomb, the unfortunate man spent miserable weeks and months, subsisting on the stores of cheese hoarded in his hut, without light and air, and in constant fear that the rocks above his head might give way and bury him under their ruins. With all the energy of despair, he endeavoured to find his way out of the mighty mound- of rubbish, and at length, after incredible toil, emerged into the open daylight. More like a spectre than a human being, pale and emaciated, with torn clothes, and covered with bruises, he knocked at the door of his house* in the lower valley, where his wife and children, who had already long reckoned him among the dead, were at first terrified at his ghost-like appearance, and called in the village pastor to convince them of his identity, before they ventured to rejoice at his return. On the road from Sallenches to Servoz, in the Valley of the Arve, well known to all the visitors of Mont Blanc, may be seen the ruins of a high mountain which collapsed in the year 1751, causing so dreadful a crash and raising such clouds of dust that the whole neighbourhood thought the world was at an end. The black dust was taken for smoke ; flames had been seen darting about in the murky clouds, and the report spread to Turin that a new Vesuvius had suddenly opened its subterranean furnaces among the highest of -the Alpine mountains. The king, alarmed or interested at the news, immediately sent the famous geologist Vitaliano Donati to gather accurate information on the spot. Donati, travelling night and day, with all the eagerness of a zealous naturalist, arrived while the appalling phenomenon was still in full activity. 'The peasants,' writes Donati to a friend, 'had all fled from the neighbourhood, and did not venture to approach * It is almost' superfluoue to meution that in the Alps many of the peasants lead a migratory existence. During the summer they ascend, with their herds, into the higher valleys, where they remain, separated from their families, uptil the first night-frosts force them to return to their homes on a lower level. ' LANDSLIP OF THE ROSSBEEG. ]'2S the crasMng mountain witliin a distance of two Italian miles. The country around was covered with dust, which closely resembled ashes, and had been carried by the wind to a distance of five miles. I examined the dust, and found it to consist of pulverised marble. I also attentively observed the smoke, but could see no flames, nor could I perceive a sulphurous smell ; the water also of the rivulets and sources showed no trace of sulphurous matter. This convinced me at once that no volcanic eruption was taking place, and pene- trating into the cloud of dust which enveloped the mountain, I advanced close to the scene of the commotion. I there saw enormous rocks tumbling piecemeal into an abyss with a dreadful noise, louder than the rolling of thunder or the roar of heavy artillery, and distinctly saw that the smoke was nothing but the dust rising from their fall. 'Further investigations also showed me the cause of the phenomenon, for I found the mountain to consist of horizon- tal strata, the lowest being composed of a loose stone of a slaty texture, while the upper ones, though of a more compact nature, were rent with numerous crevices. On the back of the mountain were three small lakes, the water of which, penetrating through the fissures of the strata, had gradually loosened their foundations. The snow, which had fallen during the previous winter more abundantly than had ever been known within the memory of man, hastened the progress of destruction, and caused the fall of six hundred million cubic feet of stone, which alone would have sufiiced to form a great mountain. Six shepherds, as many houses, and a great number of cowS and goats have been buried under the ruins. ' In my report to the king I have accurately described the causes and effects of the catastrophe, and foretold its speedy termination — a prediction which has been fully verified by the event — and thus the new volcano has become extinct almost as soon as its formation was announced.' Fortunately, this grand convulsion of nature, which spread consternation far and wide, caused the death of but a few victims. The landslip of the Eufi or Eossberg, which, on Sep- tember 2, 1806, devastated the lovely Vale of Goldau, and over- whelmed four villages, with their rich pasture-grounds and 124 THE SUBTERRANEAN WOKLD. gardens, was far more disastrous. The preceding years had been -unusually wet, the filtering waters had loosened the Nagelfluh, or coarse conglomerate of which the mountain is composed, and the rains having latterly been almost continuous, a great part of the mountain, undermined by the .subterranean action of the waters, at length gave way and was hurled into the valley below. Early in the morning the shepherds who were tending their herds on the mountains perceived fresh crevices in the ground and on the rock walls. In many parts the turf appeared as if turned up by a ploughshare, and a cracking noise as if roots were violently snapped asunder was heard in the neighbouring forest. Prom, hour to hour, the rents, the cracking, the rolling down of single stones increased, until finally, at about five in the afternoon, a large chasm opened in the flanks of the mountain, growing every instant deeper, longer, and broader. Then from the opposite Rigid the forest might be seen to wave to and fro like a storm - tossed sea, and the whole flank of the mountain to slide down with a constantly increasing velocity, until finally hundreds of millions of cubic feet of rock came sweeping down into the valley with a noise as if the foundations of the earth were giving way. The friction or clash of the huge stones, hurled against each other in their fall, produced so intense a heat that flames were seen to flash forth from the avalanche, and the moisture with which they were saturated, being suddenly changed into steam, caused explosions like those from the crater of a volcano. Dense clouds of dust veiled the scene of destruction, and it was not before they slowly rolled away that the whole extent of the disaster became visible. Where, but a few hours since, four prosperous villages — Goldau, Busingen, Upper and Lower Eothen, and Lowerz — had been gilded by the sun, and numerous herds bad been grazing on the rich pastures along the borders of the lake of Lowerz, nothing was now to be seen but a desolate chaos of rocks, beneath which .457 persons lay buried. From this terrible disaster some wonderful escapes are recorded. High on the slope of the Eossberg, lived Blasi Mettler, with his young wife Agatha. When, in the morning, the first premonitory signs, of the. disaster appeared, and the labouring. LANDSLIP OP THE VALE OF GOLDAU. 125 moiintain began to raise its warning voice, the superstitious peasant, fancying lie heard the jubilee of demons, hastened down to Arth, on the bank of the lake of Zug, and begged the parish priest, with tears and lamentations, to accompany him, and exorcise the evil spirits with a copious sprinkling of holy water. While he was still speaking, the catastrophe took place, and he now rushed back again to his hut, where beyond all doubt his beloved wife and his only child, which was but four weeks old, had found a premature grave. Meanwhile A.gatha had spent several anxious hours. She was preparing her humble evening meal when the thunder- ing uproar and the shaking of the hut filled her with the terrors of death. Seizing the infant, which lay awake in its cradle, she crossed the threshold, while the soil under her feet slid down into the valley. Escaping into the open air, she looked back and saw her hut and a sea of huge stone blocks roll down into the vale below, while the spot on which she stood remained unmoved. In this situation she was found by Blasi, who, though a poor and ruined man, still thanked God for the wonderful preservation of his family. About a thousand feet lower down the mountain lived Blasi's brother Bastian, who, when the mountain slipped, was tending his herd on the opposite Eighi. But his wife and her two little children were in his hut when it was buried beneath the stony avalanche. After the terrible commotion had subsided, the relations of Prau Mettler, anxious to ascer- tain her fate, hastened to the scene of desolation. The hut had disappeared, the green Alpine meadow was covered with a heap of ruins, but, not far from the former site of the hum- ble cottage, the youngest child lay quietly sleeping. At the peril of his life, one of the infant's relations clambered over the ruins and rescued the little sleeper, who, unhurt amidst the falling rafters of the hut and the ruins of the crumbling mountain, had been carried away with the bed on which he was reposing. On my last visit to Switzerland, I was in- formed that Sebastian Meinhardt Mettler, the child thus wonderfully saved, died in the year 1867, at the age of sixty- one. Some of the victims who had been buried in the ruins of the villages were dug out and restored to daylight ; others, 126 THE SUBTERKANEAK WORLD. less fortunate, may have slowly perislied, immured in a living grave ; but by far the greater number were no doubt sud- denly killed. The total number of those who were saved, either by the assistance of their friends, or by a timely flight, or by absence from their homes at the time of the disaster, amounted to 220 ; but more than double that number perished, and probably there was not one among the survivors who had not to lament the loss of friends and kinsfolk. This dreadful catastrophe also levied its tribute among the strangers whom the beauties of Alpine scenery annually attract to Switzerland. A party of tourists had left Arth in the afternoon with the intention of spending the night in Schwyz. Part of the company had already entered the ill- fated village of Goldau, and the others were a.bout to follow, when suddenly the thundering roar of the sliding moun- tain caused them to stop. Looking up and seeing rocks, forests, huts, all rushing down in horrible confusion, they instinctively ran back for their lives. The warning came not one instant too soon, for close behind the spot where they stopped panting for breath, the stones still fell like hail. But their unfortunate companions, the wife and daughter of Baron Diesbach, Colonel Victor von Steiger, and some boys, whose tutor had been slowly following them with the Baron, were buried beneath the ruins. From the Eighi the traveller still looks down upon the avalanche of stones, and the flank of the Rossberg still plainly shows the spot where, more than half a century ago, the masses of rock now reposing in the valley detached themselves from the mountain. But the beautifying hand of vegetation has already done much to adorn the scene of ruin. Green mosses have woven their soft carpet over the naked stones, while grasses and flowers, and in some places even shrubs and trees, have sprung up between them. The tears also which once were shed over the victims of the great catastrophe have long since been dried, and its last witnesses have passed away to make room for a new genera- tion, who remember the mountain-slip which buried their fathers only as a legend of the past. This terrible disaster, however appalling through the far- spread desolation it entailed, has yet been equalled or sur- FREQUENCY OF LANDSLIPS. 127 passed by others of a like nature. In the fifth century, the old Roman town of Velleja was buried under the ruins of the Eavinazzo Mountain, and the bones and coins dug out of its ancient site prove that no time was left to the inhabitants for flight. Tauretuuum was once a flourishing Roman town, situated on the south bank of the lake of Geneva, at the foot of the Dent d'Oche. In 563 it was utterly destroyed by a disruption of the overhanging mountain. The avalanche of stones which at that time was hurled down upon the devoted city is still visible as a promontory projecting far into the lake, which is here at least 500 feet deep. The immense wave caused by the rocky mass as it plunged into the water inundated the opposite shore from Morges to Vevay, and swept away every homestead that lay on its path. In the night of September 4, 1618, the falling of the Monte Conto, in the Vale of Chiavenna, so completely buried the small town of Pliirs and the village of Scilano, that of their 2,430 inhabitants but three remained alive, and but one single house escaped the universal destruction. At pre- sent, magnificent chestnut-trees grow upon the mound of ruins and cast their shade over the graves of the long-for- gotten victims. Three villages, with their whole population, were covered in the district of Treviso when the Piz moun- tain fell in 1772 ; and the enormous masses of rock which in 1248 detached themselves from Mount Grenier, south ^f Chambery in Savoy, buried five parishes, including the town and church of Saint Andre, the ruin occupying an extent of about nine square miles. Sometimes the same village has been repeatedly destroyed • by mountain-slips. Thus excavations have shown that Brienz, a hamlet built on the borders of the lake of the same name, on a mound of accumulated ruins, has been twice overwhelmed by a deluge of stones and mud, and twice reconstructed. It would be useless to multiply examples of the under- mining power of water. I will merely add that it is impossible to wander through the valleys of Switzerland without being struck by the sight of the sloping hillocks of rubbish piled up against the foot of every gigantic rock wall, which in many cases can only be attributed to that cause. Some 128 THE SUBTEERANKAN WORLD. are entirely overgrown with large firs, thus showing that the last stony avalanche took place at a remote period ; others are desolate heaps of rubbish, which evidently prove that the work of destruction is constantly going on, and that the highest peaks will ultimately be levelled with the plain. Over many a hamlet the sword of Damocles is continually suspended in the shape of a j^reoipitous rock-wall, or of a forest-crowned mountaiu-bi'ow. For years the undermining- waters are slowly and secretly at work, and then suddenly the crisis takes place. AX.MOUTH LAN])WLIP. Were the history of the Andes or of the Himalayas as familiar to us as that of the Alps, we should be able to relate many like instances of disastrous mountain-slips. But the high places of the earth do not alone bear witness to the power of aqueous erosion, for wherever the soil is undermined, it may be precipitated to a lower level. Thus, the pheno- ]nenon is by no means uncommon in England, though rarely occurring on so large a scale as in the landslip which took jilace at Axmouth in Dorsetshire, on December 24, 1839. ' The tract of downs ranging there along the coast,' says Sir Charles Lyell (' Principles of Geology'), ' is capped by chalk, ^vhich rests on sandstone, beneath which is more than 100 THE AXMOUTII LANDSLIP. 129 feet of loose sand, the whole of these masses reposing on retentive beds of clay shelving towards the sea. Numerous springs, issuing from the loose sand, have gradually removed portions of it, and thus undermined the superstratum. In 1839, an excessively wet season had saturated all the rocks with moisture, so as to increase the weight of the incumbent mass, from which the support had already been withdrawn by the action of springs. Thus, the superstrata were pre- cipitated into hollows prepared for them, and the adjacent masses of partially undermined rock to which the motion was communicated, were made to slide down, on a slippery basis of watery sand, towards the sea. These causes gave rise to a convulsion, which began on the morning of December 24, with a crashing noise ; and, on the evening of the same day, fissures were seen opening in the ground, and the walls of tenements rending and sinking, until a deep chasm or ravine was formed, extending nearly three-quarters of a mile in length, with a depth of from 100 to 150 feet, and a breadth exceeding 240 feet. At the bottom of this deep gulf lie frag- ments of the original surface, thrown together in the wild est confusion. In consequence of lateral movements, the tract intervening between the new fissure and the sea, including the ancient underclifiF, was fractured, and the whole line of sea-cliff carried bodily forwards for many yards. This motion of the sea-cliff produced a further effect, which may rank among the most striking phenomena of this catastrophe. The lateral pressure of the descending rocks urged the neigh- bouring strata, extending beneath the shingle of the shore, by their state of unnatural condensation, to burst upwards in a line parallel to the coast, so that an elevated ridge, more than a mUe in length and rising more than forty feet, covered by a confused assemblage of broken strata and immense blocks of rock, invested with seaweed and corallines, and scattered over with shells and starfish, and other productions of the deep, forms an extended reef in front of the present range of cliffs.' Landslips caused by the falling in of cavern roofs are no- where more common than in the cretaceous strata, which are more liable than others to be undermined by the action of run- ning waters. In the vast chalk-range extending from Carinthia to the Morea, they occur of all sizes, from a diameter of a few - K 130 THE SUBTERKANEAN WORLD. fathoms to one of many thousand feet, and are not seldom of considerable depth. They are generally funnel-shaped, some- times elongated ; and the bottom of the larger ones is gene- rally covered with villages, orchards, vineyards, or consider- able tracts of arable land. In Dalmatia, Carinthia, Carniola, and Istria, where the country consists chiefly of arid plateaux or mountain-chains, exposed to the dry north-easterly winds, the cultivation of the soil is almost exclusively confined to these depressions or dolUnas, which, as a further protection against the cutting blasts, are inclosed with walls of loose stones. Besides the funnel-shaped landslips or doUinas, there are others with perpendicular sides like walls or shafts, which are called jam.as or mouths. One of these (near Breschiak) descends to a depth of 384 feet. The hares seek a winter refuge in the dollinas, and the jamas, as the favourite resort of pigeons, are also called pigeon-holes or goluhinas. Many a pedestrian has lost his life by falling into a jama, par- ticularly in former times, when fewer precautions were taken to protect the stranger against these treacherous precipices. In the Jura Mountains there are also whole rows of caul- dron-shaped depressions ; and in North Jutland, where the chalk formation is likewise very extensive, a recent landslip suddenly emptied the Norr Lake, which lost itself in sub- terranean channels. Effects very similar to those of an ordinary landslip are sometimes produced by the bursting of a bog. On the western confines of England and Scotland, the Solway Moss occupies a flat area about seven miles in circumference. Its surface is covered with grass and rushes, presenting a dry crust and a fair appearance ; but it shakes under the least pressure, the bottom being unsound and semi-fluid. The adventurous passenger therefore, who sometimes, in dry seasons, traverses this treacherous waste, must pick his way over the rushy tussocks as they appear before him, for here the soil is firmest. If his foot slip, or if he venture to move in any other part, it is possible he may sink never to rise again. On December 16, 1.772, this quagmire, having been filled, like a great sponge, with water, during heavy raii)s, swelled VOLCANIC FISSURES. 131 to an unusual height above the surrounding country, and then burst. The turfy covering seemed for a time to act like the skin of a bladder retaining the fluid within, till it forced a passage for itself, when a stream of black half- consolidated mud began at first to creep over the plain, resembling in the slow rate of its progress an ordinary lava-current. No lives were lost, but the deluge totally overwhelmed some cottages, and covered 400 acres with a mass of mud and vegetable matter, which in the lowest parts of the submerged area was at least fifteen feet deep. It may easily be imagined that in Ireland, the classic land of bogs, such phenomena are not uncommon. In the peat of Donegal an ancient log-cabin was found, in 1833, at the depth of fourteen feet. The cabin was filled with peat, and was surrounded by other huts, which were not examined. Trunks and roots of trees, preserved in their natural position, lay around these huts. There can be little doubt that we have here one instance out of many in which villages have been overwhelmed by the bursting of a moss. In many volcanic regions we find circular cauldron-shaped depressions in the earth's surface, which might easily be mistaken for land-slips, but which have in reality been formed by explosive discharges of confined vapours. When vents or fissures are produced by a paroxysm of volcanic energy, we can easily understand how in some cases the pent-up gases, finding a sudden outlet through some weaker part of the surface, must act like a powder mine, and scatter- ing the rocks that surrounded the orifice, leave a deep hollow behind as a memento of their fury. The depressions thus caused bear a great resemblance to real craters, from which they are, however, distinguished by the absence of a cone of scoriae and from their never having ejected lava. These curious crateriform hollows are very common in the Eifel, a volcanic region in Rhenish Prussia^ where, probably owing to the clayey nature of the soil, they have become reservoirs of water, or Maare, as they are called by the natives. Most of them still have small lakes at their bottom, while others have been drained for the sake of cultivation, or by the spontaneous rupture or erosion of their banks. Some of them are of considerable dimensions, such as that of 132 THE SUBTERRANEAN WORLD. Meerfeld, the diameter of which falls very little short of a mile ; or the Pulvermaar of Gillenfeld, remarkable for the extreme regularity of its m.agnificent oval basin. Similar lakes or Maare occur in Auvergne, in Java, in the Canary Islands, in New Zealand, and in the volcanic districts of Italy. The beautiful lakes of Albano and Nemi, which have been so often sung by ancient and modern poets, belong to this class ; but Fr. Hoffmann, a celebrated German geologist, ascribes the origin of the former to a landslip caused by the falling in of the roof of a vast subterraneau cavern. STALACTITE CAVERN AT ACGTELEK. HUNGARY: THE CAVE OF BORODLA. 133 CHAPTEE XII. ON CAVES IN GENERAL. Their various Forms — Natural Tunnels — The VentaniUas of Giialgayoc — Eimeo— Torgatten — Hole in the Miirtschenstocfc — The Trebich Cave — Grotto of Anti- paros — Vast Dimensions of the Cave of Adelsberg and of the Mammoth Cave — Discovery of Baumann's Cave — Limestone Caves — Causes of their Excavation — Stalactites and Stalagmites — Their Origin — Variety of Forms — Marine Caves — Shetland — Fingal's Cave — The Aeure Cave — Cave under Bonifacio — Grotta di Nettuno, near Syracuse — The Bufador of Papa Luna — Volcanic Caves — The Fossa della Palomba — Caves of San Miguel — The Surtshellir. THE natural excavations wh.icli abound in many mountain chains, or on rocky shores washed by the stormy sea, are extremely various in their forms. Many are mere rents or crevices in the disruptured rocks ; others wide vaults, not seldom, of hall or dome-like dimensions, or long and narrow passages branching out in numerous ramifications. Not seldom the same cave alternately expands into spacious chambers, and then again contracts into narrow tunnels or galleries. The walls of many are smooth and nearly parallel ; the sides of others are irregular and rugged. Many have narrow entrances and swell at greater depths into majestic proportions ; while others open with wide portals, and gra- dually diminish in size as they penetrate into the rock. Sometimes an excavation pierces a mountain from side to side like a natural tunnel, so as to allow a passage to the light of day. Such, among others, are the numerous per- forations or windows (ventanillas) in the serrated bastions of the rich silver mountain Gualgayoc in the Peruvian Andes, or the opening through one of the high peaks of the romantic island of Eimeo which rises within sight of Tahiti out of the dark blue ocean. According to a popular tradition, this hole owes its origin to Oro, the powerful god of war, who, having 134 THE SUBTEREANEAN WORLD. one day quarrelled with the minor god of Eimeo, hurled his mighty spear at him over the sea. As even gods, when losing their temper, are apt to miss their aim, the puny delinquent escaped unhurt, while the dreadful lance flew like a thunderbolt through the mountain, leaving the perforation as a lasting memorial of its passage. In Europe we likewise meet with several remarkable instances of such natural tunnels. One of the most celebrated is the grotto of Tor- gatten in ISTorway, which perforates a huge rock, 400 feet above the level of the sea. Its proportions are truly colossal, as it is no less than 900 feet long by from 80 to 100 feet broad ; and the arches of its vast portals measure resj)ectively 200 and 120 feet. Its floor is nearly horizontal, and covered with fine sand ; its sides are smooth, as if they had been chiselled by the hand of man. Tbe sea, with its numberless cliffs and white-crested breakers, appears through the immense gallery as through the tube of a gigantic telescope, and in fine sunny weather affords a spectacle of incomparable beauty. Whoever has visited the romantic lake of Wallenstadt, in Switzerland, will have had his attention directed to a tunnel near the summit of the almost inaccessible Miirtschenstock, a favourite resort of the chamois. It is visible from the lake near the hamlet of Miihlehorn, and, though of considerable dimensions, appears to the eye like a mere speck of snow on the huge grey rockwall, which towers to a height of 7,617 feet. Prom the 1st to the 8rd of February, at 2 o'clock in the afternoon, the inhabitants of Miihlehorn see through this aperture the disk of the sun for the first time after a long winter. In the structure of some caves a vertical direction pre- dominates; as, for instance, in the Trebich Cave, three leagues from Trieste, which consists of several perpendicular shafts, connected by narrow transversal passages, and de- scending one after another, until finally, at a depth of more than a thousand feet, the cavern terminates in a wide vaulted space spanning a subterranean river. Such, also, is the renowned Grotto of Antiparos, into which the visitor is let down by a rope to a depth of about twenty fathoms. After reaching a tolerably even platform, he is obliged to THE MAMMOTH CAVE OF KENTUCKY. 135 descend another precipice, and tlien to proceed over slippery rocks until he finally reaches the terminal vault. In most caverns, however, the chief direction is horizontal, either on several planes, separated from each other by more or less steep passages, or on a single level. The dimensions of caves are as various as their forms. Many are small and of inconsiderable depth — mere holes worn in the rock ; while others are of a truly astonishing size, and fatigue the wondering spectator as he wanders through their lofty halls or endless galleries. The famous Cave of Adelsberg in Carniola has been explored to a distance of 1,243 fathoms from the chief entrance ; and in the Mammoth Cave in Kentucky no less than 226 avenues branch out to the right and left from the main gallery, so as to form a network of subterranean passages and halls of various dimensions, whose total length has been computed at about 160 miles ! As many caves are without any visible communication with the external world, and the entrance of others is frequently narrow, and concealed behind rocks in solitary ravines on wild hill slopes or steep sea shores, far from the busy haunts of man, we cannot wonder that chance has frequently been instrumental in their discovery. Sometimes a hunter pursuing a wild animal has been led to the hidden cave in which it sought a refuge, or the workmen in a quarry have been suddenly surprised at meeting with a hollow in the rock, which opened an unexpected passage into the bowels of the mountain. The digging of wells, of cellars, of foundations, the boring for mines or Artesian wells, has often revealed the existence of unknown sub- terranean chambers ; and so recently as 1868, one of the finest known caverns, which already attracts a number of delighted visitors, was discovered in the neighbourhood of the thriving manufacturing town of Iserlohn in Westphalia, on blasting a rock for the making of a railway. We may thus infer that a vast number of caves must still be totally unknown ; many so situated that chance may one day lead to their discovery ; while others are hollowed out at such vast depths in the earth-rind as to be for ever inaccessible to man. Even of those caves which have been objects of curiosity 136 THE SUBTEKRANEAN WORLD. for centuries, many have still been by no means thoroughly explored. In the year 1848 an American gentleman per- suaded the guides of Baumann's Cave in the Harz Moun- tains to accompany him on a voyage of discovery through parts of the cavern hitherto untrodden by man. It was no easy task to clamber over slippery rocks and deep chasms yawning into black abysses ; but curiosity and the spirit of adventure kept leading them on from passage to passage and vault to vault, when suddenly the lights began to burn more dimly ; and the glass of the guiding compass having been accidentally broken warned them to retrace their steps. They had been wandering for twenty-four hours in the subterranean labyrinth, and after so long an absence from the light of day, joyfuUy hailed the green hill slope which decks that mysterious palace of the. gnomes. Franz Baumann, the first discoverer of the cavern, was less fortunate. Its tortuous windings confused the expert and intrepid miner, who lost his way in the recesses of the cave. While seeking in vain for an outlet, his sparing light went out. Three days he groped about in darkness, until at length, worn out and exhausted, he was led by a wonderful chance to the mouth of the cave. Before he died he had yet suiBcient strength briefly to mention the wonders he had seen during his fatal expedition. His descendants still enjoy the privilege of serving as guides to the visitors of the cave, and never fail to relate the melancholy end of their ill- fated forefather. Grottoes and caves occur in every kind of rock, in lavas, basalt, slate, and granite, as well as in limestone, dolomite, and gypsum ; for the volcanic powers are capable of rending the hardest stone, and the foaming breakers of a turbulent ocean meet with no cliff that is able ultimately to resist their never-tiring assaults. But, owing to their great fragility and to the solubility of limestone (carbonate of lime) in water containing carbonic acid, calcareous rocks are more liable than any others to be shattered and undermined, both by volcanic and aqueous causes. Its water readily absorbs carbonic acid gas. Every drop of rain that falls upon the ground necessarily contains some small portion of this gas, which, as we all know, is THE CAVE OF ADELSBEEG. 137 constantly mixed with tlie atmosphere, and thus becomes a solvent for chalk; more particularly if the latter, as, for instance, iu the Karst Mountains of Carniola, contains some proto-carbonate of iron, which, changino- into an oxide when E^STiiANCE TO THE CA\T2 OF ADELSDETIG. in contact with water, yields its carbonic acid to the per- colating fluid, and consequently increases its solvent powers. Hence every shower of rain that filters through the crevices of a limestone rock wears away some part of its mass ; and if we consider the vast number of years ovei* which these 138 THE SUBTEEEANEAN WORLD. operations have extended, and add to their effects the trans- porting powers of the waters on their progress through the subterranean channels which they have excavated or enlarged, we can easily comprehend how in the course of ages whole mountains may be hollowed out. As the streams that flow on the surface of the earth are constantly altering their courses, thus also the subterranean waters are ever active in excavating new channels in the bosom of the rock. Finding at length new outlets on a lower leval, they abandon their ancient beds, and the ex- plorer now wanders dry-footed where once a foaming river gushed along. The Cave of Adelsberg is a remarkable example of the changes which the subterranean waters, aided by time or by the disrupting power of earthquakes, may thus bring about ; for the Poik now flows beneath its galleries in the same north-easterly direction, in a channel which is for the greatest part unknown and inexplorable, so that the dry cave of the present day must evidently have been the old river-bed. But nowhere can be found such perfect, unequivocal, and abundant proofs of the action of running water in corroding and excavating new passages in a soluble rock as in the huge Mammoth Cave. The rough-hewn block in the quarry does not bear more distinct proof of the hammer and the chisel of the workman than these interminable galleries afford of its denuding and dissolving power. At Niagara we see a vast chasm evidently cut by water for seven miles, and still in progress ; but we cannot see beneath the cataract the water- worn surface, nor the rounded angles of the precipice ; while the frosts and rains of countless winters have reduced the walls of the chasm itself to a talus of crumbling and moss-grown rocks. But in the Mammoth Cave we see a freshness and perfection of surface such as can be found only where the destructive agencies of meteoric causes are wholly absent. Here we have the dry beds of subterranean rivers exactly as they were left thousands of years ago by the streams which flowed through them when Niagara was young. No angle is less sharp, no groove or excavation less perfect, than it was originally left when the waters were suddenly drained off by cutting their way to some lower level. The very sand ACTION OP WATEE IN CAVES. 139 and rounded pebbles, which now pave the galleries and which anciently formed the bed of the stream, have remained in many of the more distant galleries untrodden even by the foot of man. ' The rush of ideas was strange and overpowering,' says Professor Silliman, ' as I stood in one of these before unvisited avenues, in which the glow of a lamp had never before shone, and considered the complex chain of phe- nomena which were before me. There were the delicate silicious forms of cyathophylli and encrinites protruding from the softer limestone, which had yielded to the dis- solving power of the water ; these carried me back to that vast and desolate ocean in which they flourished, and were entombed as the crystalline matrix was slowly cast around them, mute chroniclers of a distant epoch. Then suc- ceeded the long periods of the upper secondary, and, these past, the slow but resistless force of the contracting sphere elevated and drained the rocky beds of the ancient ocean. The action of the meteorological causes commenced, and the dissolving power of fresh water, following the almost in- visible lines of structure in the rocks, began to hollow out these winding paths slowly and yet surely.' What a lesson for the thoughtful spectator, and how vast a prospect into the dark abysses of the past here unrolls itself before him ! After abandoning the vaults where they once collected and formed a running stream, the waters, filtering through the porous limestone, begin to ornament them with lustrous petrifactions ; for whether below or above the surface of the earth, Nature ever loves to decorate her works. The moisture, charged with carbonate of lime, evaporates or parts with its free carbonic acid in coming into contact with the air of the cave ; the carbonate, now no longer held in solution, precipitates and forms calcareous incrustations or excres- cences, which in course of time assume every variety of fan- tastic shape, either hanging like icicles from the vault (sta- lactites), or rising in columns (stalagmites) from the floor of the cave where the dripping water deposited its spar. Some- times stalactites and stalagmites join as they continue to grow in opposite directions, and ultimately form pillars which appear to sustain the roof. On considering the simple physical and chemical agencies 140 THE SUBTERRANEAN WORLD. which are at work in the formation of these beautiful pro- ductions — solution, mechanical dripping, evaporation, and precipitation — a great similarity might naturally be expected in their forms ; but here also Nature shows herself as a con- summate artist, and with the simplest means brings forth an astonishing variety of effects. As among the leaves of a forest there are not two perfectly alike, thus also every stalactite differs from another ; and the celebi'ated traveller Kohl affirms that every stalactital cave has its peculiar style or character of decoration. The causes to which stalac- tites owe their existence are indeed everywhere the same, but the circumstances under which the drops fall and evaporate are so various that in each case some new shape is produced. Thus all the infinite diversity of forms which we admire in the corals and sponges of the seas, is wonderfully repeated in the dark vaults of the subterranean world. The variety and beauty of their colouring likewise eon- tribute to adorn these formations. They are generally white, sometimes rivalling the purity of snow, and trans- lucent, even when of considerable thickness, but often also green, brown, yellow, red, orange — a variety of tints which produces the most pleasing effects, and is chiefly owing to the metallic salts with which the water has been impreg- nated while filtering through the calcareous rock. All these wonderful plays of Nature, in which form and colour contribute to delight the eye or to charm the fancy of the spectator, are, however, still less interesting than the reflections suggested by the slow growth of stalactites in general, and the enormous size which some of them attain. Inscriptions seventy or eighty years old appear covered only with a thin translucent coat of sinter, and in the Cave of Adelsberg names scratched in the walls more than six centuries ago are still perfectly legible. How many ages must, then, have passed before such colossal stalagmites could have been formed as, for instance, in the Australian cavern explored by Mr. Woods,* or in the Cave of Corneale, near Trieste, where we find one of these formations measuring fifty feet in circumference, and another rising thirty-five feet above the ground, with a trunk as massive as that * ' The Geology of South Australia.' ST.OW FORJ[ATIOX OF CAVERNS. 141 of an old oak. Tho ruins of Thebes, or the rock-temiiles of Ipsamboiil, appear almost as works of the present day \vhen compared with those amazing- monuments of time. But, Mdiile meditating- on their colossal dimensions, the mind is necessarily carried still further back, and wanders thr( wgh the countless ages which the filterincp waters, collectin"- into :-.TAr.Ar"i'irAf. 'AVEKN IN AISTI; \IA subterranean streams, required Ibi- hollowing out the vast cavities on whose floor those gigantic stalagmites were sub- sequently deposited. An epoch of still older date presents itself when the limestone rocks, now pierced with vast sta- lactital caverns, were first slowly forming at the bottom of the primeval sea Isy the accumulation of countless exuvite of zoophytes, star-fishes, and foraminifera, and after growing- 142 THE SUBTEKRAKEAN WORLD. into strata many hundred feet thick, were then forced iip- wards by plutonic powers, and became portions of the dry land. Nor is this the end of the vast perspective, for changes still more remote loom in the fathomless distance. The mind grows giddy while thus plunging into the abyss of time, and, in spite of the ideas of sublimity awakened by such meditations, feels a painful sense of its incapacity to conceive a plan of such infinite extent. While on land the running or filtering waters restlessly pursue their work of excavation, the tumultuous waves of the ocean impress on every rocky shore the seal of their tremendous power. As, day after day, and year after year, the billows strike against the cliffs that oppose their progress, they undermine their foundations, scoop out wide portals in their projecting headlands, and hollow out deep caverns. Hera also water appears as the beautifjing element, decorating inanimate nature with picturesque forms ; and the sea nowhere exhibits more romantic scenes than on the bold coasts against which her waves have been beating for many a millennium. During the calm ebb tide seals are often seen sunning themselves at the entrance of the oceanic grottoes, while cormorants stand before them as guardians of the dark galleries beyond ; the waves murmur in softer strains, and the screeching sea-mew glides with his silvery pinions through the tranquil air ; but when the stormy flood batters against the coast, the billows rush into the caverns, scaring all animal life away, and no voice is heard but that of the ocean. Our coasts abound in beauties such as these, particularly on the wild shores of Shetland or the stormy Hebrides — ' AVhere rise no groves and where no gardens blow, Where even the hardy heath scai'ce dares to grow ; But rocks on rocks, in miet and storm arrayed. Stretch far to sea their giant colonnade.'— Scott. Along the coast of the mainland of Shetland and the neighbouring islets of Bressay and Noss, cape follows upon cape, consisting of bold cliffs hollowed into caverns, or divided into pillars and arches of fantastic appearance, by the constant action of the waves. As the voyager passes THE CAVE OF CAPEI. 143 the most nortlierly of these headlands, and turns into the open sea, the scenes become yet more sublime. Rocks, upwai'ds of three or four hundred feet in height, present themselves in colossal succession, sinking perpendicularly into the sea, -which is very deep, even within a few fathoms of their base. All these huge precipices abound with caves, many of which run much farther into the rock than the boldest islander has ever ventured to penetrate. One of these marine excavations, called ' The Orkneyman's Harbour,' is remarkable for the circumstance of an Orkney vessel having once run in there to escape a French privateer. Sir Walter Scott, who visited this interesting spot, found the entrance lofty enough to admit his six-oared boat without striking the mast, but a sudden turn in the direction of the cave would have consigned him to utter darkness if he had gone in further. The dropping of the sea fowl and cormo- rants into the water from the sides of the cavern, when disturbed by his approach, had something in it wild and terrible. The shores of Caithness and of Sutherland, and of many of the islets in the Highland seas, likewise exhibit many wonderful specimens of the fantastic architecture of the ocean ; but pre-eminent above all in grandeur and renown is Fingal's Cave. Sir Walter Scott, who twice visited this celebrated grotto (in 1810 and 1814), pronounced it above all description sublime. ' The stupendous columns and side-walls, the depth and strength of the ocean with which the cavern is filled, the variety of tints formed by stalactites dropping and petrifying between the pillars, and resembling a sort of chasing of yellow or cream-coloured marble, filling the interstices of the roof — the corresponding variety below, where the ocean rolls over a red, and in some places a violet- coloured rock, the basis of the basaltic pillars — the dreadful noise of those august billows, so well correspondiug with the grandeur of the scene — are all circumstances elsewhere un- paralleled.' In the Azure Cave of Capri, the Mediterranean possesses a marine grotto rivalling Fingal's Cave in celebrity, and no less wonderful in its peculiar style of beauty. As the roof of 144 THE SUBTEREANEAN WOELD. its narrow entrance rises only a few feet above tlie level of tlie sea, it is probable that no buman eye bad ever been deligbted witb its cbarms before 1826, wben it was acci- dentally discovered by two Prussian artists who were swim- ming in the neighbourbood. After passing tbe low portal the cave widens to grand proportions, 125 feet long and 145 feet broad, and except a small landing-place on a pro- jecting rock at tbe further end, its precipitous walls are on all sides bathed by the influx of tbe waters, which, in that sea, are so clear that the smallest objects may be distinctly seen on the bottom of the deep basin, the most beautiful bathing-place a mermaid might wish for. All the light that enters the grotto must first penetrate the whole depth of the waters before it can be reflected into the cave, and it thus acquires so blue a tinge, from the large body of clear water through which it has passed, that the walls of the cavern are illumined by a radiance of the purest azure. Had Byron known of the existence of this magic cave, Childe Harold would surely have devoted some of his most brilliant stanzas to its praise. In many other parts of the Mediterranean the limestone rocks that fringe its shores have been worn into magnificent caverns, less singular, indeed, than the fairy grot of Capri, but still of rare and wonderful beauty. Such, among others, is the Antro di Nettuno, in the island of Sardinia, about twelve miles from the small seaport of Alghero.* Exceedingly picturesque caverns have also been worn by tbe chafing waters in the chalk cliff's under Bonifacio, in the island of Corsica. Their entrances festooned with hanging boughs, they penetrate far into the interior of the rocks, and the water percolating through their vaulted roofs has formed stalactites of fantastic shapes. The boat glides through the arched entrance, and the glaring sunshine without is replaced by cool and grateful shade. Fishes are flitting in the clear water ; limpid streams oozing through the rocks form crystal basins witb pebbly bottoms ; and the channels from the blue sea, flowing over the chalk, become cerulean. Poetic fancy has never pictured anything more enchanting than these lovely caves. * ' The Sea and its Living Wonders,' 3rd edit. p. 49. SUBTEEEANEAN WATEB-COUESES. 145 The rocky coast of Sicily is likewise hollowed out with numerous marine grottoes, which, though rarely noticed by travellers, may well be ranked amongst the greatest natural beauties of the island. One of the most remarkable is the Grotta di Nettuno, near Syracuse, which, in calm weather, admits a boat to a considerable distance. Its rugged vaults rise to a height of about twenty or thirty feet, and are covered with stalactites wherever the water does not reach. There is no landing-place, and throughout the whole cave the water is as deep as in the open sea beyond. Nothing CAVE TJNDEIt BONIFACIO. can be more charming than to look back from the dark recesses of the grotto upon the bright sunshine without, and to listen to the soothing murmurs of the clear waves as they ripple against the rocky walls. The atmosphere is so pure in this delicious climate that not a trace of fog or mist obscures even the remotest parts of the cave, and the serene daylight falling through the entrance renders even its deepest shadows translucent. Here a lover of nature might linger for hours enjoying the most delicious coolness, and watching the charming effects of light and shade in their ever-varying play. 146 THE SUBTERRANEAN WORLD. On many rocky shores tlie ocean has worn out subterranean channels in the cliffs, against which it has been beating for ages, and then frequently emerges in water-spouts, or foun- tains, from the opposite end. Thus in the Skerries, one of the Shetland Islands, a deep chasm or inlet, which is open overhead, is continued underground, and then again opens to the sky in the middle of the island. When the tide is high, the wares rise up through this inland aperture, with a noise like the blowing of a whale. Similar phenomena occur on the south side of the Mau- ritius,* on the north coast of Newfoundland, near Huatulco on the Mexican coast of the Pacific, and near Peniscola, in Spain, where a cave, through whose roof at storm tides the sea bursts with a terrific noise, has receivgd the name of the ' Bufador, or the water-spout of Pope Luna,' the family name of Benedict XIII., who, having been deposed by the Councils of Pisa and Constance, retired to the small Spanish town where he was born. As the chief occupation of the holy father in exile was to vent a continuous torrent of curses and excommunications upon his numerous enemies, it is probable that this circumstance caused his name to be given to the noisy but harmless Bufador. Though water, aided by time, is probably the chief exca- vating power, there can be no doubt that the action of subterranean fire has likewise produced, and still produces, many hollows in the hard crust of the earth. Wherever a volcano has been piled up to the skies, the matter ejected from its vents must necessarily have left a void behind, and given rise to corresponding cavities in the space beneath. The shock of an earthquake must frequently rend asunder deep-seated rocks, and the slow upheaval of considerable tracts of land can hardly be supposed to take place without the formation of hollows and crevices. When the lavas poured forth during an eruption are in a liquid state, they do not form on cooling a compact homo- geneous mass, but generally exhibit a porous, spongy texture, due to the bubbles of the vapour generated through, or entangled in, their mass. These bubbles frequently unite in »■ ' The Sea and its Living Wonders,' 3rd edit. p. 62. VOLCANIC CAVES OF PUNTA DELGADA. 147 larger volumes, which, influenced by their elasticity and inferior specific gravity, rise towards the surface of the lava as it flows on, and, when sufficiently powerful, raise its crust in dome-like or conical protuberances, which not seldom burst open at the summit, or crack at the sides. The hollows thus formed are often so large as to entitle them to the name of caves. According to Sir Charles Lyell, the sudden conversion into steam of lakes or streams of water, overwhelmed by a fiery current, may perhaps explain the formation of many of the extensive underground passages or caverns which form a common feature in the structure of a volcano. Great volumes of vapour, thus produced, may force their way through liquid lava, already coated over externally with a solid crust, and may cause the sides of such passages, as they harden, to assume a very irregular outline. The famous cave on Etna, called the Fossa della Palomba, which opens near Nicolosi, not far from Monte Eossi, has not improbably been thus formed. After reaching the bottom of a hollow 625 feet in circumference at its mouth, and 78 feet deep, the explorer enters another dark cavity, and then others in succession, sometimes descending precipices by means of ladders. At length the vaults terminate in a great gallery ninety feet long, and from fifteen to fifty feet broad, beyond which there is still a passage never yet visited, so that the whole extent of the Fossa remains unknown. The volcanic caves of Punta Delgada in the Island of San Miguel, one of the Azores, are stUl more grand. Their entrance is through a narrow crevice, which soon, however, expands into an enormous hall, whose vault even the strongest torch-light is unable to illumine. In one spot, an opening in the floor shows that the lava, which is here but a foot thick, forms the roof of a second cave, situated below the first, into which even the boldest explorer has never ventured, but the noise of stones cast into the abyss proves it to be of considerable size. The first-mentioned cave leads into another, the width of which is estimated by Webster* at 120 feet ; but the height he was unable to measure. Gradu- ally this cave becomes narrower and lower, until, about * ' Description of the Island of Saint Michael.' us THE SUBTERRANEAN WORLD. 450 feet from tlie entrance, it terminates in a low vanlt. Black lava stalactites everywhere liang down from tlie roof, and the floor is so covered with sharp-sided blocks of the same volcanic material that walking among them becomes a task of the greatest difficulty. While a lava-stream is flowing along, a slag-crust forms on its surface, inclosing the internal fluid matter as in a canal. But when the supply of fresh lava from the vent diminishes or entirely ceases, the still liquid interior at the central part of the current continuing for some time to flow on, often leaves behind hollow gutters, arched over by a thin and brittle roof — so thin sometimes as to yield to the weight of a person stepping on them. Such vaulted roofs have pseudo-stalactitic projections left by the subsidence of the liquid, and are coated with a glossy varnish. Sometimes, very large caverns are thus formed beneath the surface of a lava-stream, and even rival in their extent and windings the caves worn by water in limestone rocks. The famous Surt- shellir,* situated near Kalmanstunga in Iceland, is a remark- able instance of a vast lava excavation owing its origin to this cause. It has very appropriately been named after Surt, the prince of darkness and fire, of the ancient Scandinavian mythology ; for this gloomy deity could not possibly have chosen a fitter residence than its vast and dismal halls, once glowing with subterranean fires, and now the seat of per- petual darkness. » ' The Polar World,' p. 58. 149 CHAPTER XIII. CAVE KIVEES. The Fountain of Vancluse — The Pontaine-sans-fond — The Katabothra in Morea — Subterranean Eivers in Carniola — Subterranean Navigation of the Poik in the Cave of Planina — ' The Stalactital Paradise ' — The Piuka Jama. WHEREVER large bodies of water gusli fortli in a rapid stream from the bowels of the earth, they m.ust either have flowed through wide underground channels, or they must come from extensive lake-like reservoirs, for the mere drainage of a porous stratum is evidently incapable of ac- counting for their production. Thus the celebrated fountain of Vaucluse, near Avignon, which has the volume and power of a river at its very source, is undoubtedly fed by a subterranean sheet of water of considerable extent. Even when least abundant, it pours forth upwards of 13,000 cubic feet of water in a minute ; and after the country has been flooded with abundant rains, this volume is increased fourfold. The environs of the fountain are extremely picturesque, and justify the praises which have been lavished upon it in the immortal strains of Petrarch. It fiUs a large oval basin, vaulted by a spacious cave, and its waters, which, when low, escape through subterranean chan- nels into the deep bed of the Sorgue, rise, when high, over the rock-wall at the mouth of the grotto, and form a broad cataract, rushing down with a dreadful noise. Near Sable in Anjou, a source, or rather a pit from eighteen to twenty-four feet in diameter, well known in the country under the name of the Bottomless Fountain {Fontaine-sans- fond) sometimes overflows its brink, and then casts forth a large quantity of fish, so that it is evidently a mere aperture in the vault of a large subterranean pool. In the department of the Haute Saone, another pit, called 150 THE SUBTEREANEAlSr WORLD. the Frais Puits, presents a similar phenomenon. After abundant rains, the water gushing forth from its mouth inundates the neighbourhood, and on its retiring, pikes are not seldom found scattered over the surface of the flooded fields or meadows, a sure proof that the Puits must commu- nicate with a large subterranean cavity. Nothing is more common in limestone districts than the engulfment of rivers, which, after holding a subterranean course of many miles, escape again by some new outlet. The Guadiana loses itself in a flat country in the midst of an immense savannah, and hence the Spaniards, when the mag- nificent bridges of London or Paris are mentioned to them, boastfully reply that they have one in Estramadura on which more than a hundred thousand oxen graze at a time. In the vast limestone formation which, under various names, extends through Carinthia, Carniola, Istria, Dalmatia, Albania, and Greece, the whole country is perforated like a sponge by an intricate system of subterranean water-courses. In the more elevated districts of the Morea there are many deep land-locked valleys or basins inclosed on all sides by mountains of cavernous limestone. When the torrents are swollen by the rains, thej'- rush from the surrounding heights into these basins ; but, instead of forming temporary lakes, as would be the case in most other countries, they are swallowed by chasms, which are sometimes situated in the middle of the plain, constituting the bottom of the closed basin, but more commonly at the foot of the surrounding escarpment of limestone. During the dry season, which in Greece alternates almost as distinctly as between the tropics with a period of rain, these chasms are the favourite retreats of wild animals. Sometimes, in the limestone formation, the same stream repeatedly gushes forth from some cavernous recess, and then again disappears. The caves of Adelsberg, Planina, and Upper Laibach in Carniola are traversed by the same river, which, losing its name every time it plunges into a new subterranean channel, is called, first, the Poik, then the Unz, and finally the Laibach. In the same manner the Temenitz, an afluent of the Save, thrice disappears under the earth, and thrice emerges as a new-born river with another name. CAVE OP PLANINA. 151 As far as these subterranean streams have been explored, their course exhibits awonderfulvariety of interesting under- ground scenery. Sometimes they form high cataracts, leaping over rocks so picturesquely grouped that, were they illumined by the sun, and of more easy access, they would be admired by numberless tourists ; and not seldom they expand into dark and melancholy lakes. Sometimes they with difficulty force a passage through a chaos of rocks, and then again they flow gently in a deep and even channel, so as to be navigable to a considerable distance. Generally, not the least breath of air sweeps over their placid waters, but sometimes their surface is rippled by the wind pouring in through some unseen chasm. Among the bold explorers who have launched forth their barques on unknown subterranean rivers, the late Adolph Schmidl, of Vienna, holds a conspicuous rank. In a canoe specially constructed for the purpose he trusted himself to the dark streams of Camiola, which rewarded his adventurous zeal with many a scene of incomparable beauty, where the water-spirits and the gnomes seemed to have rivalled each other in the work of decoration. To give an idea of the difficulties and of the enjoyruents of these subterranean explorations, we will follow the intrepid natura- list on his voyages of discovery through the famous Cave of Planina, through which flows the Poik, a river which is at all times deep enough to carry a boat. The course of the navigation is stream-upwards, and consequently much safer than would otherwise have been the case ; but in many places the rapidity of the current calls for great caution, and considerable strength is needed to overcome its violence ; while at the same time great care must be taken to avoid striking against the rocks that lie hidden under the water. As far as the end of a magnificent dome, situated about 600 feet from its entrance, the cave can be traversed on foot ; but here the sullen stream, completely filling its whole width, compels the explorer to trust to his canoe. When he has passed a portal about eight fathoms high and half as broad, with proportions as symmetrical as if it had been sculptured by the hand of man, the thundering roar of a distant cata- ract announces still grander scenes. The portal widens, and 152 THE SUBTERRANEAN WORLD. the astonislied explorer suddenly emerges on a lake 250 feet long and ISO feet broad, beyond wbich the cave is seen to divide into two arms, giving passage to two streams, whose confluent waters form the lake. This broad sheet of water affords an imposing but melancholy sight. The walls of the cave rise everywhere abruptly out of the water, with the exception of one small landing-place opposite to the portal at the foot of a projecting rock or promontory. Here and there large masses of stalactite hang like petrified cascades from the rocks, which are generally naked and black. The vault is so high that the light of a few torches fails to pierce its gloom, which is rendered still more impressive by the roar of the waterfall in the left branch of the cavern. As far as the lake, the cave is of comparatively easy access, and has been repeatedly visited, but the subterranean course of the two brooks beyond was first explored by Dr. Schmidl. In the left or western branch of the cave, into which he penetrated to a distance of more than a mile, his boat had to be unloaded no less than eleven times on account of the reefs that obstructed its passage, while the explorers, wading through the water, dragged it over the shallows. Once even, where the navigation was interrupted by large masses of rock, under which the tumultuous waters disappear with a dreadful roar, they were obliged to take the little shallop to pieces, and to reconstruct it on the opposite side of the mound. The navigable part of this western branch ends in a circular dome, the floor of which is entirely filled with a lake 180 feet long, and fi:om 40 to 45 feet deep. On the western bank of this lake, a chasm opens at the top of a mound of rubbish, the only place where it is possible to land. A violent gust of wind descends from this chasm, which, sloping upwards, soon narrows to a small crevice, through which the current of air sets in. To a lateral gallery, opening beyond the mouth of the chasm. Dr. Schmidl gave the name of ' The Stalactital Paradise,' on account of the uncommon beauty of the spar- crystals with which' its walls were incrusted. It was the first time that the foot of man had ever penetrated into this charm- ing laboratory of nature; no torch had ever soiled its brilliant decorations ; no profane hand had ever damaged its gem-like EXPLORATIONS OP ADOLPH SCHMIDL. 153 tapestry. Here wliole groups of stalagmitie cones, of all shapes and sizes, some like tiny icicles, others six feet higli and as thick as a man's waist, rose from the ground, while further on the brown wall formed a dark background, from which projected in bold relief the colossal statue of a scep- tered king. Near the entrance stood a magnificent white figure, which fancy might have supposed to be a cherub with a flaming sword, menacing aU those who should dare to injure the wonders which he guarded. ' " The Stalactical Paradise " remained intact,' says Dr. Schmidl.* ' I begged my companions not to strike off the smallest piece of spar as a memorial of our visit, and they all joyfully consented. Our feet carefully avoided trampling down any of its delicate ornaments ; we left it with no other memorial than our admiration of its beauty. The nymphs of the grot will no doubt have pardoned us for having intruded upon the sanctuary, where for countless centuries they had reigned in undisturbed solitude and silence.' The eastern branch of the cave, through which the main stream flows, is much larger than the branch above described; it is also easily navigated, as it contains but two reefs and a small number of cliffs. On first ascending the stream, the continually increasing roar of waters announces a consider- able waterfall. Enormous masses of stone, piled up by the falling in of the roof, have blocked up and narrowed the bed of the river to fifteen feet, and cause the stream to shoot down in a broad sheet ten feet high. The cataract, madly rushing over the jet-black rocks and casting up flakes of milk-white foam, is very beautiful, and, when brightly illuminated, must produce a truly magical effect. Beyond the cataract the river flows for a short space in an invisible channel, as its waters are completely hidden under rocks. It was no easy task to carry the planks of the dis- membered boat over these rugged blocks of stone, but after reconstructing it on the opposite side of the mound, and over- coming the minor obstacles of a couple of reefs, the river was found to flow in a deep channel between steep walls, and a free navigation opened to a distance of at least a league and a half. * ' Die Hohlenkimde des Karstes.' Wien, 185i. 154 THE SUBTERRANEAN WORLD. ' No description,' said Dr. Schmidl, ' can do justice to tlie fascination of this subterranean voyage. In some parts the roof is adorned with coral-shaped draperies of snow-white stalactites, but generally the walls are mere black, naked stone. Here and there sources gurgle down their sides, and, along with the melancholy trickling of single drops of water from the vault, alone break the silence of the dark inter- minable cave. The breathless attention we bestowed on the guidance of our boat and on the wonders that surrounded us sealed our lips, and we glided silently along through the dark waters, that now, for the first time since they began to flow, reflected the glare of a torch.' Throughout the whole distance of 1,140 fathoms beyond the second reef, there is but one landing-place ; everywhere else the walls rise precipitously from the water. In some parts the roof descends so low that the explorers were obliged to lie down in the boat and to shove it along by holding to the projections of the vault, which finally left but a few inches' space above the water, and thus opposed an invincible obstacle to all further progress. In another grotto — called the Piuka Jama — the Poik again flows in the midst of the grandest subterranean scenery. About a league to the north of Adelsberg, the wanderer, after traversing a thicket of underwood, suddenly finds himself on the brink of a yawning precipice, from the bottom of which is heard distinctly the noise of a rushing stream. The walls of the chasm are almost perpendicular, except where a small ravine, overgrown with shrubs, leads to an enormous rock, on which it is possible to stand, and, if perfectly free from giddiness, to look down into the gulf below, where the huge portal of a cave is seen to open. Prom this rock, which projects over the abyss, the only descent is by means of a rope or a rope-ladder. The bottom of the pit is covered with large blocks of stone irregularly piled up, and here one first sees the river rushing through the cave from right to left. The Piuka Jama may thus be compared to a window pierced through a vault overspanning a subterranean stream. Clambering down a heap of rubbish, the explorer at length stands upon the floor of the cave, and reaches the bank of the Poik. Stream-upwards, about 300 GROTTO OF PIUKA JAMA. 155 fathoms from tlie aperture, he meets with a rock gate, through which the river rushes so violently that a boat can master the current only when the water is unusually low. After crossing this broad portal, the last faint traces of daylight glimmering from the distant aperture in the Piuka entirely disappear, and the scene suddenly changes. The expanding cavern assumes the proportions of an imposing dome. On its left side a mound has been formed by the falling in of the roof; but every block of stone is completely covered with calcareous incrustations of the purest white. From the floor to the centre of the vault millions upon millions of brilliant spars reflect the light : every hollow in the walls is a cabinet of gems. The background of the dome completes the beauty of the scene, and exhibits one of the most im- posing cavern decorations it is possible to imagine. A mon- strous pillar rises from its centre, forming two colossal ogival portals. The larger one is on the left, and at its entrance a mighty stalagmite, above twelve feet high, seems to forbid intrusion. The pillar itself and the vaults of both the portals are ornamented with the richest stalactital drapery. When the river is swollen it rushes tumultuously through both the gates, where now Dr. Schmidl found but a scanty rill whispering and babbling among the stones. 156 THE SUBTEKEANEAK WORLD. CHAPTEE XIV. SUBTERRANEAN LIFE. Subterranean Vegetation — Fungi — Enormous Fungus in a Tunnel near Doncaster — ^Artificial Mushroom-beds near Paris — Subterranean Animals — The Guaeharo ■ — Wholesale Slaughter — Insects in the Cave of Adelsberg — The Leptodirus and the Blothrus — The Stalita tsenaria — The 01m or Proteus — The Lake of Cirk- nitz — The Archduke Ferdinand and Charon — The Blind Eat and the Blind Fish of the Mammoth CaTe. OF all tlie phenomena whicli attract the naturalist's atten- tion, as he wanders over the surface of the earth, there is none which makes a deeper impression on his mind than the omnipresence of life. On the snow-clad cone of Chimbo- razo, 18,000 feet above the level of the sea, Humboldt found butterflies and other winged insects, while, high over his head, the condor was soaring in solitary majesty. At the still greater elevation of 18,460 feet, at the Doonkiah Pass in the Himalaya Mountains, Dr, Hooker plucked flowering plants, and saw large flocks of wild geese vdnging their flight above Kunchinjiuga (22,750 feet) towards the unknown re- gions of Central Asia. Thus man meets with life as far as he is able to ascend, or as far as his sight plunges into the atmospheric ocean. Besides the objects visible to his eye, innumerable microscopical organisms pervade the realms of air. According to Ehrenberg's brilliant discovery, the im- palpably fine dust which, wafted by the Harmattan, often falls on ships when hundreds of miles from the coast of Africa, consists of agglomerations of sUica-coated diatoms, individually so small as to be invisible to the naked eye; and everywhere numberless minute germs of future life — eggs of insects and sporules of cryptogamic plants — well fitted by cUia and feathery crowns for an aerial journey, float up and down in the atmosphere; while the waters of ocean are found, in like manner, filled with myriads of animated atoms. SUBTEREANEAN VEGETATION. 157 But organic life not only occupies those parts of our globe whicli are accessible to solar ligbt ; it also dives profoundly into tbe subterranean world, wherever rain, or the melted snow, filtering through the porous earth, or through vents and crevices, is able to penetrate into natural caverns or artificial mines. For the combination of moisture, warmth, and air is able to develop organic life even thousands of feet below the surface of the earth ; while light, though indis- pensable to most creatures, would blight and destroy the inhabitants of the subterranean vaults. On surveying the flora of these dismal recesses, we find it consisting exclusively of mushrooms or fungi, the lowest forms of vegetation, which, shunning the light, love darkness and damp. Their appearance in the caves is, as everywhere else, dependent upon the existence of an organic basis, and thus they are most commonly found germinating on pieces of wood, particularly in a state of decomposition, which have been conveyed into the caverns either through the agency of man or by the influx of water. Species of a peculiarly luxu- riant growth are sometimes seen to spread over the neigh- bouring stones, or apparently to spring from the rocky ground, where, however, on closer inspection, vestiges of decayed organic substances will generally be detected. Thus vegetation in caves most commonly keeps pace with the quantity of mouldering wood which they contain, and flourishes not only near their entrance but in their deepest recesses, as, for instance, in the Cave of Adelsberg, where, at a distance of more than a thousand fathoms from its entrance, the pegs which have been driven into the stalactital walls for the purpose of measuring its length are covered with a rich coat of fungi. Nothing can be more curious than to see these plants, thriving and luxuriating in deep stillness and gloom, under circumstances so alien to the ordinary con- ditions of life. Among the fungi found in caves, many also vegetate upon the surface of the earth exposed to the influ- ence of light, and not seldom degenerate into monstrous forms in their less congenial subterranean abodes; but many are the exclusive children of darkness. The Austrian naturalist Scopoli published in 1772 the first exact descrip- tion of more than seventy subterranean fungi, collected 158 THK SUBTERKANBAN WORLD. cMeflj in the mines of Schemnitz and Idria; and about twenty jears later Humboldt wrote his celebrated treatise on the same subject.* Since then G. F. Hoffmann has de- scribed the subterranean flora of the Harz Mountains ; f and latterly the botanists Welwitsch and Pokorny have examined the caves of Carinthia, where they discovered no less than eighteen species of fungi, among others the mouse-tail mushroom {Agaricus myurus, Hoffm.), which is also found in the Harz, and bears on a slender hairy stalk, more than a foot long, a small hat, scarcely a quarter of an inch in diameter. Some of these fungi are remarkable for their size {Thelephora rubiginosa sanguinolenta) , others for their elegance {Diderma nigrvpes) . Some years ago a gigantic fungus, found growing from the woodwork of a tunnel near Doncaster, afforded a striking proof of the luxuriancy of subterranean vegetation. It measured no less than fifteen feet in diameter, and was, in its way, as great a curiosity as one of the colossal trees of California. Even the plants that flourish in the darkness of caves have been rendered subservient to our use. The cultivation of the edible mushroom in spacious caverns or ancient quarries is practised to a great extent in the environs of Paris, at Arcueil, Moulin de la Roche, and St. Germain, but particularly at Montrouge, on the southern side of the city. The mushroom-beds are entirely underground, seventy or eighty feet below the surface, at a depth where the tempera- ture is nearly uniform all the year round. These extensive catacombs, formed by long burrowing galleries, have no opening but by a circular shaft, to be descended by clamber- ing down a perpendicular pole or mast, into the sides of which large wooden pegs are fixed, at intervals of ten or twelve inches, to rest the feet upon. The baskets containing the ripe mushrooms are hoisted from below by a pulley and rope. The compost in which they grow consists of a white gritty earth, mixed with good stable manure, and is moulded into narrow beds about twenty inches high, ranged along the sides of the passages or gal- * ' Mora Frlbergensia Plantas Cryptogamicas prsssertim subterraneas exhibens. t ' Vegetabilia in Hercynise Subterraneis collecta Norinbergse,' 1811. SUBTERRANEAN ANIMAL LIFE. 159 leries, and kept exquisitely Beat and smooth. The mushroom sporules a.re introduced to the beds either by flakes of earth taken from an old bed, or else from a heap of decomposing stable manure in which mushrooms have naturally been en- gendered. The beds are covered with a layer of earth an inch thick, the earth being merely the white rubbish left by the stone-cutters above. They must be well watered, and removed after two or three months, when their bearing qualities are exhausted. In one of the caves at Montrouge alone there are six or seven miles of mushroom-bedding, a proof that this branch of industry is by no means unim- portant. While subterranean vegetation is exclusively confined to mushrooms, animal life of almost every class has far more abundant representatives, for plants are in general much more dependent on the vivifying influence of light. The various animals which are found dwelling in caves may be subdivided into two groups ; one, which, though pre- ferring darkness, and spending a great part of its existence under the earth, yet often voluntarily seeks the light of day, or at least wanders forth at night ; while the other is exclusively subterranean, and is never seen above the surface of the earth, unless by chance or when driven up by violence. To the first group belong most of the insectivorous and rodent quadrupeds that dwell in self-made burrows, or pursue a subterranean prey, such as the armadilloes and the moles. The large family of the bats likewise love to sleep by day, or to hibernate in warm and solitary caves, where they are sometimes found in numbers as countless as the sea-birds which flock round some rocky island of the north. When Professor Silliman visited the Mammoth Cave (October 16, 1822), he everywhere saw them suspended in dense clusters from the roofs, though a large number had not yet retired into winter-quarters. In a small space, scarcely four or five inches square, he counted no less than forty bats, and con- vinced himself that at least one hundred and twenty find room on a square foot, as they held not only by the surface of the walls of their retreat, but by each other, one closely crowding over another. Such clusters are found in the interior of the cavern, which branches out in many directions 160 THE SUBTERRANEAN WORLD. as far as two miles from the entrance, so that a very super- ficial survey allows them to be counted by millions. Who, in these dismal regions, where no change of temperature or of light announces the various seasons, tells them that the reign of winter is past ? who awakes them at the proper time out of the deep sleep in which they remain plunged for months ? The same mysterious voice of instinct which regulates the migrations of the birds and the wanderings of the fishes, and which in this case, as in every other, is equally wonderful and incomprehensible. In the class of birds we find many cave-haunting species. The pigeons like to nestle in grottoes, which also serve as welcome retreats to the moping owl ; and various swallows and swifts breed chiefly in the darkness of caverns. One of the most remarkable of these troglodytic birds is the Guacharo, which inhabits a large cave in the Valley of Caripe, near the town of Cumana, and of which an interesting account has been given by Humboldt, who first introduced it to the notice of Europe. The Gueva del Guacharo is pierced in the vertical profile of a rock, and the entrance is towards the south, forming a noble vault eighty feet broad and seventy- two feet high. The rock siirmounting the cavern is covered with trees of gigantic growth, and all the luxuriant profusion of an inter-tropical vegetation. Plantain-leaved heliconias, and wondrous orchids, the Praga palm, and tree arums, grow along the banks of a river that flows out of the cave, while lianas, and a variety of creeping plants, rocked to and fro by the wind, form elegant festoons before its entrance. What a contrast between this magnificently decorated portal and the gloomy mouth of the Surtshellir, imbedded in the lava wildernesses of Iceland ? As the cave at first penetrates into the moun- tain in a straight direction, the light of day does not dis- appear for a considerable distance from the entrance, so that visitors are able to go forward for about four hundred and thirty feet without being obliged to light their torches ; and here, where light begins to fail, the hoarse cries of the noc- turnal birds are heard from afar. The guacharo is of the size of the common fowl. Its hooked bill is wide, like that of the goat- sucker, and furnished at the THE GUACHARO CAVERN. 161 base with stiff hairs directed forwards. The plumage, like that of most nocturnal birds, is sombre brownish grey, mixed with black stripes and large white spots. The eyes are in- capable of bearing the light of day, and the wings are dis- proportionately large, measuring not less than four feet and a half from tip to tip. It quits the cavern only at nightfall, especially when there is moonlight ; and Humboldt remarks that it is almost the only frugivorous nocturnal bird yet known, for it does not prey upon insects like the goat- sucker, but feeds on very hard fruits, which its strong hooked beak is well fitted to crack. The horrible noise made by thousands of these birds in the dark recesses of the cavern can be compared only to the wild shrieks of the sea-mews 'round a solitary bird m.ountain, or to the deafening uproar of the crows when assembled in vast flocks in the dark fir-forests of the North. The clamour increases on advancing deeper into the cave, the birds being disturbed by the torch-light ; and as those nestling in the side avenues of the cave begin to utter their m.ournful cries when the first sink into silence, it seems as if their troops were alternately complaining to each other of the intruders. By fixing torches to the end of long poles, the Indians, who serve as guides into the cavern, show the nests of these birds, fifty or sixty feet above the heads of the explorers, in funnel-shaped holes with which the cavern roof is pierced like a sieve. Once a year, about midsummer, the Guacharo Cavern is entered by the Indians. Armed with poles they ransack the greater part of the nests, while the old birds, uttering lamentable cries, hover over the heads of the robbers. The young which fall down are opened on the spot. The peri- tonseum is found loaded with fat, and a layer of the same substance reaches from the abdomen to the vent, forming a kind of cushion between the birds' legs. The European noc- turnal birds are meagre, as, instead of feasting on fruits and oily kernels, they live upon the scanty produce of the chase ; while in the guacharo, as in our fattened geese, the accumu- lation of fat is promoted by darkness and abundant food. At the period above mentioned, which is known at Caripe as the ' oil harvest,' huts are erected by the Indians with palm leaves near the entrance, and even in the very porch of the M 162 THE SUBTERRANEAN WORLD. cavern. There the fat of the young birds just killed is melted in clay pots over a brushwood fire, and is said to be very pure and of a good taste. Its small quantity, hovrever, is quite out of proportion to the numbers killed, as not more than 160 or 160 jars of perfectly clear oil are collected from the massacre of thousands. The way into the interior of the cavern leads along the banks of the small river vrhich flovrs through its dark recesses ; but sometimes large masses of stalactites obstruct the passage, and force the visitor to wade through the water, which is, however, not more than two feet deep. As far as 1,458 feet from the entrance the cave maintains the same direction, width, and height of sixty or seventy feet, so that it would be difficult to find another mountain cavern of so regu- lar a formation. Humboldt had great difficulty in persuading the natives to pass beyond the part of the cave which they usually visit to collect the oil, as they believed its deeper penetralia to be the abode of their ancestors' spirits ; but since the great naturalist's visit, they seem to have abandoned their ancient superstitions, or to have acquired a greater courage in facing the mysteries of the grotto, for, while they would only accompany Humboldt as far as 236 fathoms into the interior of the cave, later travellers, such as Codazzi and Beaupertuis, have advanced with their guides to double the distance, though without reaching its end. They found that beyond the furthest point explored by Humboldt the cave loses its regularity, and has its walls covered with stalactites. In the embranchments of the grotto Codazzi found innumerable birds. It was formerly supposed that the guacharo was exclusively confined to this cave; latterly, however, it has also been found in the province of Bogota. The discovery of animals adapted for perpetual darkness is but of modern date, and as the vast majority of caves have not yet been thoroughly explored by zoologists, the number of genera and species already known gives us reason to believe that future investigations will add considerably to their number. In the Adelsberg, Lueg, and Magdalena grottoes, which form but an inconsiderable part of the extensive cavernous regions of Carniola, seven exclusively subterranean insects, one spider, two scorpionides, one CAVERN" BEETLES. ](53 millepede, two crnstaceans, one snail, and one reptile— in all fifteen dilierent species of animals, belonging- to no less than six ditterent classes — liave been found. Among- tliese dwellers of the dark, warfare is as rife as in the regions of light. Thus, in the recesses of the Grotto of Adelsberg, the cavern beetle (LeptodirKs Hochm- wurtii) is persecnted and devoured by the scorpioniform Blothnis qielmis, and by the eyeless spider [Stalitic Uvii- Tlie black and brown Leptodirus discovered in the arui Grotto of Adelsberg in I80I, by Count Hochenwart, is dis- tinguished by long and delicate antenuLC and legs, and comparatively small translucent and smooth elytra. The unique specimen found at the time was unfortunately lost, and although twenty-five florins were offered to the cavern guides for one of these beetles, fourteen years passed l^efore it was re-discovered in the same cave. Since then other ccjllectors have been more fortunate, particularly Prince Robert Khevenhiiller, who, during his repeated visits to the Cave of Adelsberg, captured no less than twenty specimens of the Lejrtodirus. Cautiously feeling its way with its long antenuEc, the beetle slowl}^ ascends the damp stalactital columns, and accele- rates its movements at the approach of a light. The greater number were found in the evening, thus giving reason for supposing that the Leptodirus is a noctural beetle, although it is hardly possil^le to conceive how the alternating influence of night and day can still be felt in these regions of darkness. The manner in which it is pursued by the ej^eless Blothrus (discovered in 1833, by Mr. F. Schmidt), has been several times observed by Prince KhevenhuUer. He once saw one 164 THE SUBTERRANEAN WORLD. of these cavern scorpions slowly crawling" along, stretelilng out its palpi in all directions, and evidently on the search. He immediately guessed that the animal was engaged in a hunting expedition, and soon found that he was not mis- taken, for a fine Leptodirus was crawling about four feet higher on the opposite wall. For a long time the Prince left the two insects undisturbed, until he had thoroughly convinced himself that the movements of the Blothrus were evidently regulated by those of the Leptodirus, and that the former was, beyond ail doubt, in pursuit of the beetle. A Leptodirus having been thrown along with a Blothrus into a phial, was immediately cut to pieces and devoured. The eyeless cavern spider {Stalita taenaria), with brownish palpse and a snow-wbite abdomen, is not seldom found in the hollows of the stalactites, lying in wait for the unfortunate Leptodirus. On the surface of the earth spiders are frequently obliged to fast for a very long time ; but in caverns where life is so sparingly distributed, the patience of the Stalita must be exemplary, even among spiders. Her appearance on the snow-white stalactital columns, where she only becomes visible when illumined by the full light of a taper,* is very striking. Like a vision, she sweeps away in her ivory robe, accompanied by her increasing shadow, until she finally disappears in tbe darkness. But the largest and most interesting of all the European cave animals is undoubtedly the 01m {Proteus anguinus; HypochtJwn). This enigmatic reptile was first found in the famous Lake of Cirknitz, which, communicating with un- merous subterranean caves, alternately receives and loses its waters through openings in tbe rock. After long and heavy rains the floods, which the hidden vaults are no longer able to contain, gush forth in foaming cataracts, and the lake, which generally forms but a long and narrow channel, then swells to at least three times its ordinary width. Sometimes, after a long drought, the contrary takes place, and the whole lake disappears under ground. Thus, from December 1833 to October 1834, not a trace of it was visible, so thoroughly had it concealed itself in its subterranean reservoirs, where its * Torches are not allowed to be carried in the Grotto of Adelsberg, that the Miiitcness of the stalactites may not be tarnished by the smoke. THE ^[AODALENA GllOTTo. IG5 iislies, seciu-e from the persecutions of man, mnltiplied in ii remarkable manner. Tlie 01m, wliich only casually comes to tlie light of day, along with the overflowing waters of the C!irk- nitz Lake, was first discovered in 1814, in one of its perma- nent subterranean abodes. The Magdalena or ' Black Clrotto ' situated about a league to tlie north of Adelsberg, slants abruptly into tbe bowels of the mountain. After a long and difficult passage over blocks of stone or througli soft mud, a tranc^uil pool is at length readied, which rises or falls simul- taneously with tlie waters of the Poik, and proves, by this reciprocal action, that, in all probability, all the numerous grottoes and subterranean river cliannels of this so strangely undermined country form but one vast and intricate net'work. It was in this pool, which no light illumines and no wind over Tlir; riMlTKL'S axguints. stirs, that numerous Protei were first discovered; but asliun- dreds of specimens have since found their w:iy to tlie cabinets of naturalists, to be observed, dissected, or bottled up in spirits, their number has very niucli decreased, and the time is perhaps not far distant when they will be entirely extirpated in the grotto, where from time iinmeinorial they had enjoyed an undisturbed security. The Proteus is one of those remark- able reptiles which breathe at the same time through lungs and gills, having on each side of the neck three rose-red branchiae, wdiich it retains through life, as its lungs are but imperfectly developed. It has a long, eel-like body with an elongated head, a compressed tail, and four very sh