The Dikes of Holland 



229 



The Dunes near Domburg, in the Province of Zeeland 



nothing but an artificial channel, held 

 between embankments and divided into 

 a series of sections closed by means of 

 locks. No longer does it empt}" its 

 waters into the sea at Katwijk, where 

 the light-house of Caligula once stood 

 on an island in its estuary; but when 

 the lock-tender at that point has orders 

 to do so, some of its waters are allowed 

 to escape at low tide when it is consid- 

 ered perfectly safe. The same condi- 

 tion is true of the smaller streams of the 

 polder lands. Protected on the sea side 

 by the dunes and dikes and partitioned 

 off in the interior by an endless arra}^ of 

 dikes which skirt the water-courses and 

 canals, surround polders, and also serve 

 as embankments to railroads and high- 

 ways, Holland partakes much of the 

 nature of a huge ship with w^ater-tight 

 compartments. 



The immense amount of engineering 

 which is required to keep up this com- 



plicated system of dikes and waterways 

 has always been a source of interest to 

 technical men in other countries. No 

 haphazard guesses are made as to the 

 amount of water permissible in any par- 

 ticular waterway, nor as to the height 

 or size of dikes required. Matters of 

 this nature are determined with great 

 nicety through the accumulations of 

 past experience. As one waterway is 

 frequentl}^ made to relieve another and 

 the number of combinations must be 

 varied as circumstances require, a knowl- 

 edge of the fluctuations in the levels of 

 all bodies of water becomes paramount. 

 In order to supply this information, no 

 less than 172 gage rods are maintained 

 throughout the kingdom along the 

 coasts, at estuaries, on large rivers, on 

 canals, bosoms, and small streams, and 

 a few even are located in foreign coun- 

 tries, as, for instance, the gage on the 

 Rhine River at Cologne, Germany, whi( h 



