Remedies against Inundations--Dikes of the Nile--Deposits of Tuscan
Rivers--Improvements in Tuscan Maremma--Improvements in Val di
Chiana--Coast of the Netherlands

CHAPTER V.

THE SANDS.

Origin of Sand--Sand now Carried to the Sea--Beach Sands of Northern
Africa--Sands of Egypt--Sand Dunes and Sand Plains--Coast Dunes--Sand
Banks--Character of Dune Sand--Interior Structure of Dunes--Geological
Importance of Dunes--Dunes on American Coasts--Dunes of Western
Europe--Age, Character, and Permanence of Dunes--Dunes as a Barrier
against the Sea--Encroachments of the Sea--Liimfjord--Coasts of
Schleswig-Holstein, Netherlands, and France--Movement of Dunes--Control
of Dunes by Man--Inland Dunes--Inland Sand Plains

CHAPTER VI.

GREAT PROJECTS OF PHYSICAL CHANGE ACCOMPLISHED OR PROPOSED BY MAN.

Cutting of Isthmuses--Canal of Suez--Maritime Canals in Greece--Canals
to Dead Sea--Canals to Libyan Desert--Maritime Canals in Europe--Cape
Cod Canal--Changes in Caspian--Diversion of the Nile--Diversion of the
Rhine--Improvements in North American Hydrography--Soil below
Rock--Covering Rock with Earth--Desert Valleys--Effects of
Mining--Duponchel's Plans of Improvement--Action of Man on the
Weather--Resistance to Great Natural Forces--Incidental Effects of Human
Action--Nothing Small In Nature