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—DI¬ 
VERSION OF RHINE—DRAINING OF THE ZUIDERZEE—WATERS OF THE KARST 
-SUBTERRANEAN WATERS OF GREECE—SOIL BELOW ROCK—COVERING ROCKS 
WITH EARTH-WADIES OF ARABIA PKTR.1EA-INCIDENTAL EFFECTS OF HUMAN 
ACTION-RESISTANCE TO GREAT NATURAL FORCES—EFFECTS OF MINING- 
ESPY’S THEORIES—RIYER SEDIMENT—NOTHING SMALL IN NATURE. 
Cutting of Marine Isthmuses. 
Besides the great enterprises of physical transformation ot 
which I have already spoken, other works of internal improve¬ 
ment or change have been projected in ancient and modern 
times, the execution of which would produce considerable, and, 
in some cases, extremely important, revolutions in the face of 
the earth. Some of the schemes to which I refer are evidently 
chimerical; others are difficult, indeed, but cannot be said to 
be impracticable, though discouraged by the apprehension of 
disastrous consequences from the disturbance of existing natu¬ 
ral or artificial arrangements ; and there are still others, the 
accomplishment of which is ultimately certain, though for the 
present forbidden by economical considerations. 
When we consider the number of narrow necks or isthmuses 
which separate gulfs and bays of the sea from each other, or 
froln the main ocean, and take into account the time and cost, 
