POLDER, a word used in the topography of the Netherlands, is the name given to land below the level of the sea or nearest river, which, originally a morass or lake, has been drained and brought under cultivation. An embankment, forming a canal of suffi cient height to command a rim toward the sea or river, is made, and when carried quite round, as in the case of the Haarle:n lake, it is called the riag/Nart. At one or more points on the embankment apparatus for lifting water is placed, and worked by wind or steam power. If the lake deepens toward the center, several embankments canals are necessary, the one within the other, formed at different levels as the water surface becomes lessened, a connection' maintained with the outer canal, which secures a run for the drainage water. In the Schermer polder, north Holland, are four canal levels, the laud between forming long parallelograms. The water from the inner space is lifted into the first canal: that again, with the drainage of the second section, is thrown into the second, and so on until the outer canal is reached, and a fail obtained.
The Netherlands polders are very numerous. The Beemster, a rich district of north Holland, till 1612 water, is crossed at right angles by fine avenues, and dotted with farm houses and orchards. In 1805. pop. 3,938. The Zype, Schermer, and Purifier are fertile polders, hut the most important is the drained Haarlem lake (q.v.). The land reclaimed amounted to nearly .50,000 acres, and, in 1875, had a pop. of 12,570:with 2,867 horses, 5,897 head of horned cattle, 7,923 sheep, etc. There were in cultivation—colza, 633 acres; madder, 818; flax, 2,572; beans, 2,353; potatoes, 737; wheat, 4,533- rye, 2,303; barley, 2,145; oats, 12,734; beet, 400; peas, 737; mustard, 95; canary seed, 42; and other crops, 270. In 1874 in the Haarlemmeer were 614 births, 311 deaths, and 95 marriages. In connection with the new canal from the North sea to Amsterdam, several extensive tracts of land have been reclaimed from the Ij, and formed iuto valuable polders, soma of which are now bearing heavy crops.