46 The Port of Ymuiden. [January, 
equal to that of the main canal. The total length of dykes 
constructed is about 40 miles, and the excavation from the 
canals has amounted to about 13 millions of cubic yards of 
sand and mud. 
The spaces outside the canal, being pumped dry, become 
suitable for meadows, or, as they are called “ polders.” In 
order to keep them dry from percolation or drainage, 
pumping-engines are placed at certain distances along the 
canal, which drain them and empty the water into the 
canal. The total amount reclaimed, and to be reclaimed, 
is 12,450 acres. These polders continue along the canal 
side until the sand dunes are reached at 3 miles from the 
west coast. 
The canal is crossed at two points by railway bridges, but 
the most important engineering works are the locks at 
either end of the canal, which deserve a brief description 
here. 
As has been already stated, the North Sea locks are placed 
1300 yards from the western end of the canal. In these, 
special precautions were necessary to protect them from 
high tides. The locks are unusually high and strong, and 
are provided with extra gates, to be used when the tide rises 
above a certain height. Here there are two locks and a 
sluice, the larger of the two locks being capable of admitting 
a vessel 393J feet long and 59 feet wide, with a depth over 
sill of 28 feet 8 inches at ordinary low water. The walls of 
this lock are of brickwork, the exposed faces of which are 
of pressed bricks, and the rest of the work of ordinary hard 
burned bricks. In the case of the smaller lock an earthen 
slope supplies the place of the southern wall along the lock 
pond. 
The Zuyder Zee locks at Schellingwoude have been named 
the “ Orange Locks,” after the heir apparent to the throne 
of Holland. Side by side in the long dyke, which is nearly 
a mile long, are three locks for ships, one sluicing lock, and 
three masonry channels for pumping out, by steam, the 
water when the tide in the Zuyder Zee is higher than the 
water in the canal. The largest ship lock is 315 feet long 
and 59 feet wide ; the length of the other two is 239 feet, 
and their width 46 feet. These locks are built on a founda- 
tion of 8896 piles, and the dyke rests on mattrasses of 
fascines laid on the mud. The dyke is composed of sand 
and clay laid on fascines, and faced on the sea side with 
blocks of basalt and granite covered with clay. These 
locks have altogether twenty-seven pairs of gates, of which 
eleven pairs are of iron and sixteen of wood. The lock 
