But in North Holland and Utrecht on the contrary the polder water has generally to be raised.
Boezems, like polders, have a standard water-level which may not be exceeded, and as in the polder this level may vary in the different parts of an extended boezem.
The roads are divided into national or royal roads, placed directly under the control of the waterstaat and sup- 'ported by the state; provincial roads, under the direct control of the states of the provinces, and almost all supported by the provincial treasuries; communal and polder roads, maintained by the communal authorities and the polder boards; and finally, private roads.
In the Frederiks Park is a pump-room supplied with a powerful chalybeate water from a spring, the Wilhelminabron, in the Haarlemmer Polder not far distant, and in connexion with this there is an orthopaedic institution adjoining.
To increase the reservoir capacity of the polder, as well as to conduct the water to the windmills or engines, it is intersected by a network of ditches cut at right angles to each other, the amount of ditching required being usually one-twelfth of the area to be drained.