346 
DRAINING OF LAKES AND MARSHES. 
b. Draining of Lakes and Marshes. 
The substitution of steam engines for the feeble and uncer¬ 
tain action of windmills, in driving pumps, lias much facil¬ 
itated the removal of water from the polders, and the draining 
of lakes, marshes, and shallow bays, and thus given such an 
impulse to these enterprises, that not less than one hundred 
and ten thousand acres were reclaimed from the waters, and 
added to the agricultural domain of the Netherlands, between 
1815 and 1858. The most important of these undertakings 
was the draining of the Lake of Haarlem, and for this purpose 
some of the most powerful hydraulic engines ever constructed 
were designed and executed.* The origin of this lake is un¬ 
known. It is supposed by some geographers to be a part of 
an ancient bed of the Rhine, the channel of which, as there is 
good reason to believe, has undergone great changes since the 
Homan invasion of the Netherlands ; by others it is thought 
to have once formed an inland marine channel, separated from 
the sea by a chain of low islands, which the sand washed up 
by the tides lias since connected with the mainland and con¬ 
verted into a continuous line of coast. The best authorities, 
however, find geological evidence that the surface occupied by 
the lake was originally a marshy tract containing within its 
limits little solid ground, but many ponds and inlets, and 
much floating as well as fixed fen. 
In consequence of the cutting of turf for fuel, and the de- 
solidation. On the coast of Zeeland and the islands of South Holland, the 
tides, and of course the surface of the lands deposited by them, are so high 
that the polders can he drained by ditching and sluices, but at other points, 
as in the enclosed grounds of North Holland on the Zuiderzee, where the 
tide rises but three feet or even less, pumping is necessary from the be¬ 
ginning.— Staking, Voormaals en Thans , p. 152. 
* The principal engine—called the Leeghwater, from the name of an 
engineer who had proposed the draining of the lake in 1641—was of 500 
horse power, and drove eleven pumps making six strokes per minute. 
Each pump raised six cubic metres, or nearly eight cubic yards of water to 
the stroke, amounting in all to 23,760 cubic metres, or above 31,000 cubic 
yards, the hour.— Wild, Die Niederlande , i, p. 87. 
