426 ANCIENT HYDRAULIC WORKS. 
has been very sensibly modified by the operations I have de- 
scribed, and on this coast, at least, man has acted almost as 
powerfully on the physical geography of the sea as on that of 
the land.* 
Ancient Hydraulic Works. 
The hydraulic works of the Netherlands and of the neigh- 
boring states are of such magnitude that—with the exception of 
the dikes of the Mississippi—they quite throw into the shade all 
other known artificial arrangements for defending the land 
against the encroachments of the rivers and the sea, and for 
reclaiming to the domain of agriculture and civilization soil 
long covered by the waters. But although the recovery and 
protection of lands flooded by the sea seems to be an art wholly 
of Netherlandish origin, we have abundant evidence that, in 
ancient as well as in comparatively modern times, great enter- 
prises more or less analogous in character have been success- 
fuliy undertaken, both in inland Europe and in the less familiar 
countries of the East. 
In many cases no historical record remains to inform us 
when or by whom such works were constructed. The Greeks 
and Romans, the latter especially, were more inclined to under- 
take and carry out stupendous material enterprises than to 
boast of them; and many of the grandest and most important 
constructions of those nations are absolutely unnoticed by con- 
temporary annalists, and are first mentioned by writers living 
after all knowledge of the epochs of the projectors of these 
works had perished. Thus the aqueduct known as the Pont du 
Gard, near Nimes, which, though not surpassing in volume or 
in probable cost other analogous constructions of ancient and 
of modern ages, is yet among the most majestic and imposing 
remains of ancient civil architecture, is not so much as spoken 
* See, on the influence of the artificial modification of the coast-line on 
tides and other marine currents, STARING, De Bodem van Nederland, i., p. 
279. 
