Chapter III: The Woods

The Habitable Earth originally Wooded--The Forest does not
furnish Food for Man--First Removal of the Woods--Effects
of Fire on Forest Soil--Effects of the Destruction of the
Forest--Electrical Influence of Trees--Chemical Influence
of the Forest.

Influence of the Forest, considered as Inorganic Matter, on
Temperature: _a_, Absorbing and Emitting Surface; _b_, Trees
as Conductors of Heat; _c_, Trees in Summer and in Winter;
_d_, Dead Products of Tree; _e_, Trees as a Shelter to Grounds
to the leeward of them; _f_, Trees as a Protection against
Malaria--The Forest, as Inorganic Matter, tends to mitigate
extremes.

Trees as Organisms: Specific Temperature--Total Influence of
the Forest on Temperature.

Influence of Forests on the Humidity of the Air and the Earth:
_a_, as Inorganic Matter; _b_, as Organic--Wood Mosses and
Fungi--Flow of Sap--Absorption and Exhalation of Moisture by
Trees--Balance of Conflicting Influences--Influence of the
Forest on Temperature and Precipitation--Influence of the
Forest on the Humidity of the Soil--Its Influence on the Flow
of Springs--General Consequences of the Destruction of the
Woods--Literature and Condition of the Forest in different
Countries--The Influence of the Forest on Inundations--
Destructive Action of Torrents--The Po and its Deposits--
Mountain Slides--Protection against the Fall of Rocks and
Avalanches by Trees--Principal Causes of the Destruction of
the Forest--American Forest Trees--Special Causes of the
Destruction of European Woods--Royal Forests and Game Laws--
Small Forest Plants, Vitality of Seeds--Utility of the
Forest--The Forests of Europe--Forests of the United States
and Canada--The Economy of the Forest--European and American
Trees Compared--Sylviculture--Instability of American Life, 128

CHAPTER IV.

THE WATERS.

Land artificially won from the Waters: _a_, Exclusion of the Sea
by Diking; _b_, Draining of Lakes and Marshes; _c_, Geographical
Influence of such Operations--Lowering of Lakes--Mountain Lakes--
Climatic Effects of Draining Lakes and Marshes.

Geographical and Climatic Effects of Aqueducts, Reservoirs,
and Canals--Surface and Underdraining, and their Climatic and
Geographical Effects--Irrigation and its Climatic and Geographical
Effects.

Inundations and Torrents: _a_, River Embankments; _b_, Floods of
the Ardeche; _c_, Crushing Force of Torrents; _d_, Inundations of
1856 in France; _e_, Remedies against Inundations--Consequences
if the Nile had been confined by Lateral Dikes.

Improvements in the Val di Chiana--Improvements in the Tuscan
Maremme--Obstruction of River Mouths--Subterranean Waters--
Artesian Wells--Artificial Springs--Economizing Precipitation, 330

CHAPTER V.

THE SANDS.

Origin of Sand--Sand now carried down to the Sea--The Sands of
Egypt and the adjacent Desert--The Suez Canal--The Sands of
Egypt--Coast Dunes and Sand Plains--Sand Banks--Dunes on Coast of
America--Dunes of Western Europe--Formation of Dunes--Character of
Dune Sand--Interior Structure of Dunes--Form of Dunes--Geological
Importance of Dunes--Inland Dunes--Age, Character, and Permanence
of Dunes--Use of Dunes as Barrier against the Sea--Encroachments
of the Sea--The Luemfjord--Encroachments of the Sea--Drifting
of Dune Sands--Dunes of Gascony--Dunes of Denmark--Dunes of
Prussia--Artificial Formation of Dunes--Trees suitable for Dune
Plantations--Extent of Dunes in Europe--Dune Vineyards of Cape
Breton--Removal of Dunes--Inland Sand Plains--The Landes of
Gascony--The Belgian Campine--Sands and Steppes of Eastern
Europe--Advantages of Reclaiming Dunes--Government Works of
Improvement, 451

CHAPTER VI.

PROJECTED OR POSSIBLE GEOGRAPHICAL CHANGES BY MAN.

Cutting of Marine Isthmuses--The Suez Canal--Canal across Isthmus
of Darien--Canals to the Dead Sea--Maritime Canals in Greece--
Canal of Saros--Cape Cod Canal--Diversion of the Nile--Changes
in the Caspian--Improvements in North American Hydrography--
Diversion of the Rhine--Draining of the Zuiderzee--Waters of
the Karst--Subterranean Waters of Greece--Soil below Rock--
Covering Rocks with Earth--Wadies of Arabia Petraea--Incidental
Effects of Human Action--Resistance to great Natural Forces--
Effects of Mining--Espy's Theories--River Sediment--Nothing
small in Nature, 517