338 CHARACTER OF GROUNDS DIKED IN. 
mates that not less than six hundred and forty thousand bun¬ 
der, or one million live hundred and eighty-one thousand 
acres, of fen and marsh have been washed away, or rather 
deprived of their vegetable surface and covered by water, and 
thirty-seven thousand bunder, or ninety-one thousand four 
hundred acres of recovered land, have been lost by the destruc¬ 
tion of the dikes which protected them.* The average value 
of land gained from the sea is estimated at about nineteen 
pounds sterling, or ninety dollars, per acre; while the lost 
fen and morass was not worth more than one twenty-fifth 
part of the same price. The ground buried by the drifting of 
the dunes appears to have been almost entirely of this latter 
character, and, upon the whole, there is no doubt that the soil 
added by human industry to the territory of the Netherlands, 
within the historical period, greatly exceeds in pecuniary value 
that which has fallen a prey to the waves during the same era. 
Upon most low and shelving coasts, like those of the Neth¬ 
erlands, the maritime currents are constantly changing, in 
consequence of the variability of the winds, and the shifting 
of the sandbanks, which the currents themselves now form and 
now displace. While, therefore, at one point the sea is ad¬ 
vancing landward, and requiring great effort to prevent the 
undermining and washing away of the dikes, it is shoaling at 
another by its own deposits, and exposing, at low water, a 
gradually widening belt of sands and ooze. The coast lands 
selected for diking-in are always at points where the sea is 
depositing productive soil. The Eider, the Elbe, the Weser, 
the Ems, the Rhine, the Maas, and the Schelde bring down 
large quantities of line earth. The prevalence of west winds 
prevents the waters from carrying this material far out from 
the coast, and it is at last deposited northward or southward 
from the mouth of the rivers which contribute it, accordinsr to 
the varying drift of the currents. 
The process of natural deposit which prepares the coast for 
diking-in is thus described by Staring: “ All sea-deposited soil 
* Staeing, Voormaah en Thans , p. 1G3. 
