408 LAND GAINED BY DIKING. 
fully won from the ocean has been entirely lost; in others it 
has been recovered by repairing or rebuilding the dikes and 
pumping out the water. Besides this, the weight of the dikes 
gradually sinks them into the soft soil beneath, and this loss of 
elevation must be compensated by raising the surface, while the 
increased burden thus added tends to sink them still lower. 
“Tetens declares,” says Kohl, “that in some places the dikes 
have gradually sunk to the depth of sixty or even a hundred 
feet.” * For these reasons, the processes of dike-building have 
been almost everywhere again and again repeated, and thus 
the total expenditure of money and of labor upon the works 
in question is much greater than would appear from an esti- 
mate of the actual cost of diking-in a given extent of coast- 
land and draining a given area of water-surface.t 
Loss of Land by Incursions of Sea. 
On the other hand, by erosion of the coast-line, the drifting 
of sand-dunes into the interior, and the drowning of fens and 
morasses by incursions of the sea—all caused, or at least 
greatly aggravated, by human improvidence—the Netherlands 
* Die Inseln und Marschen der Herzogthiimer Schleswig und Holstein, iii., p. 
151. 
+ The purely agricultural island of Pelworm, off the coast of Schleswig, 
containing about 10,000 acres, annually expends for the maintenance of its 
dikes not less than £6,000 sterling, or nearly $30,000.—J. G. Kon, Jnseln 
und Marschen Schleswig’s und Holstein’s, ii., p. 894. 
The original cost of the dikes of Pelworm is not stated. 
“The greatest part of the province of Zeeland is protected by dikes measur- 
ing 250 miles in length, the maintenance of which costs, in ordinary years, 
more than a million guilders [above $400,000]. . . . The annual expendi- 
ture for dikes and hydraulic works in Holland is from five to seven million 
guilders” [$2,000,000 to $2,800,000].—Wixp, Die Niederlande, i., p. 62. 
One is not sorry to learn that the Spanish tyranny in the Netherlands had 
some compensations, The great chain of ring-dikes which surrounds a large 
part of Zeeland is due to the energy of Caspar de Robles, the Spanish governor 
of that province, who in 1570 ordered the construction of these works at the 
public expense, as a substitute for the private embankments which had pre- 
viously partially served the same purpose.—WILD, Die Niederlande, i., p. 62. 
