174 
As to the artificial features of Holland, we find that from 
the very earliest times it has been divided into districts of 
greater or less extent, placed under the control of a govern- 
ing body ( Waterschappen), which we may call the Hydraulic 
Administration; the-boundaries of these administrations (which 
are not conterminous with those of the provinces, or any fiscal 
or municipal districts) are formed by large and lofty dykes, in 
which are placed self-acting sluices for the discharge of the 
waters within the boundary dyke, and closing against the admis- 
sion of any of the external waters. Lake Haarlem is situated in 
the administration of the Rynland, which has discharging sluices 
into the German Ocean at Katwyck, into the Zuyder Zee at 
Sparndam and Halfwege, and into the river Yssell at Gouda. 
Within every Hydraulic Administration are three divisions 
of surface, called the Natural Lands, the Basin, and the Pol- 
ders. The basin is the total area of water-surface within the 
boundary dyke ; the natural lands area little above the level of 
the basin, and discharge the rain-fall off their surface naturally ; 
the polders are lands below the level of the basin, at various 
depths, from a few inches to twenty feet, and from which, con- 
sequently, the water must be raised mechanically, by windmills 
generally, and latterly by steam-power. The Rynland con- 
tains— 
Das a ei bse a te. ce | COG UOC Benes 
Natural lands," . 2)... +, LOU = 
PORMCLEy se a ee RE tee 
305,000 acres. 
Lake Haarlem, which had been part of the basin, is now 
added to the polders, so that, instead of 56000 and 173000 
acres, we now have 11500 acres of basin, and 217500 acres of 
polders, in this Administration. Regarding, then, the basin in 
its most important duty, that, namely, of a receptacle of the 
rain-fall when the self-acting sluices may happen to be closed 
against the external waters, we see how greatly its powers of 
