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conclusions may be drawn as to the shifting of the dunes. After having been sacked and burned by the Batavians, rebuilt again and destroyed once more by the Normans at a later date, the ruins of the castle were during the eighth and ninth centuries gradually covered by the shifting sands of the dunes, which were slowly being transplanted landward by the winds. The ruins disappeared and had been forgotten, when suddenly, after the severe storm of Christmas, 1520, they reappeared once more, but on the beach west of the dunes. Since that time they have in the course of centuries repeatedly been denuded and covered up again, and at the present day lie submerged in the sea.


It has been estimated from these facts that the dunes near Katwijk have migrated east a distance of two miles in about eighteen centuries. At other points along the western coast of Holland this receding movement has amounted to as much as six and seven miles during the same period.

It was not easy to put a stop to this alarming recession of the coast and consequent loss of land, together with the destruction of numerous flourishing villages. It has been permanently effected, however, by planting on the seaward. side of the dunes a species of grass (Arundo arenacea), known in Holland as "Helm." This plant can sustain itself very readily in the finest and purest of sands by means of extraordinarily long and intricate roots, and is therefore well qualified to counteract the shifting of sand. The grass is planted by hand in tufts not quite two feet apart, aligned in rows. That this was a laborious piece of work needs no demonstration, when it is borne in mind that there extend along the coast of Holland a chain of dunes of a total length of 200 miles, varying in width

from 400 yards to three miles, while the elevations range from 60 to 200 feet above sea-level. In other places forest growth has been started on the dunes lying further inland, and the results have been very gratifying.


The retrogression of the dunes was a source of alarm; yet, on account of its slowness, the movement had not at first made itself manifest. Very serious. changes had taken place, however, in the interior within a comparatively short period. Furious storms in the North Sea during the years 693, 782, 839, and again in 1170, 1230, and 1237 had caused a washing away of large sections of peat land situated between Lake Flevo and the North Sea. This wholesale destruction of land culminated in 1250, 1287, and 1295, when during the spring tides of those years Lake Flevo had become an inlet of the North Sea. It is estimated that this loss amounted to nearly 1,500 square miles of land, and submerged a number of flourishing villages. Heavy dikes were then built, inclosing the so-formed Zuider Zee, except at such points where it communicated with other bodies of water, in order to check all further encroachments on the land. Its form has since been practically the same as now appears on our maps.

With the advent of the fourteenth century began a period of active dikebuilding in Holland. Not only the Zuider Zee had swallowed much rich, arable land, but many of the interior bodies of water, at times of storms, were making similar trouble, and inundations caused by the large rivers were frequent. Obviously, as the country became more closely settled and land became more valuable, every new inundation caused more loss of life and property than had

previous inundations. These catastrophes, attended with the loss of thousands and thousands of lives, fill many a sad page in the history of the country. Dike-building became a serious matter and began to receive the attention which it had long needed. Flimsy dikes and levees were gradually transformed into heavier structures, and the physical outlines of the Netherlands were thus rendered more permanent and may be said to have suffered little change since that time.

The province of North Holland about the year 1288, although extensively protected by numerous dikes, was dissected by bodies of water of all sizes, such as the Schermer, the Beemster, the Purmer, the Starnmeer, the lakes west of Alkmaar, and the Langemeer, connecting with each other, and also with the Zuider Zee at several points. It was possible in those days to navigate from Amsterdam westward through the Ij, then through the lakes mentioned, and return by way of the Zuider Zee, without finding an obstacle in the form of a dike, or as much as a lock. With the expansion of Lake Flevo into a wide-mouthed inlet of the North Sea, the action of the dreaded tides and storms of the latter were carried into the very heart of the country, thereby raising considerably the levels in the lakes before mentioned and threatening new inundations. To remedy this dangerous situation, the three channels connecting the lakes with the Zuider Zee were closed by means of heavy dams during the years 1311-1400. In the main, however, the aspect of the country changed little between 1288 and 1575. Before the beginning of the seventeenth century there probably was felt little need of securing additional arable land; possibly pecuniary difficulties forbade the expenditure of the large sums required for draining the lakes, and more likely difficulties of a technical nature stood in the way. At any rate, the lakes drained during the fifteenth

and sixteenth centuries were few in number. About the middle of the fifteenth century windmills for raising water were coming into use in Holland. These were at first of a primitive character and of low power, but they were applied to the pumping out of lakes in process of reclamation.


The great period for reclaiming land, however, did not begin until the early part of the seventeenth century, at a time when prosperity returned in Holland and great enterprises of divers character were begun. With the revived interest in agriculture and cattle-raising, the rich soils covered by the lakes became valuable, and every effort was made to drain them or to keep them within the smallest limits. This became urgent for the further reason that new lakes were constantly being created by the digging away of the peat for fuel. Between the years 1607 and 1643 sixteen lakes were permanently drained, adding to the territory of the Netherlands, within the space of 36 years, an area of 91 square miles, or nearly 60,000


All these lakes were drained with the aid of windmills. A lake was first inclosed by a dike to cut it off from surrounding bodies of water. This work was always of a difficult nature, consuming much time and money, as it frequently happened that during some storm the dike gave way. The inclosing dike once completed, the windmills, constructed in the meantime, commenced draining off the water into adjacent waterways. These latter were properly connected with each other to keep up the navigation in that section of the country and to carry off the water pumped out of the lake. Such a system of communicating waterways and canals is collectively known as a "bosom," and they in their turn dis

charge the surplus water into the sea at times of low tide, while at times of high tide they are closed by means of locks. Even after the lake had been drained the same system was preserved, only less windmills being required to keep the lake bottom dry. In general, any section of land artificially drained, and known in the Dutch language as a "polder," has a "bosom " surrounding it, into which is delivered by the windmills all the water that collects in the polder. The polder, for this reason, is intersected by a network of ditches, carefully spaced and graded in such a manner as to drain the surplus moisture from the soil and conduct it to the windmills. The amount of ditching required to ac

complish this as a rule covers an area equivalent to one-twelfth of the total area to be drained. Thus the Hollanders not only keep their polders dry, but provide at the same time ample means for navigation, the main canals and ditches being from 25 to 40 feet in width.

Before the invention of the steamengine, windmills were exclusively employed in the work of draining the polders, but as the power of a windmill is rather limited, the lift was as a rule inconsiderable. In later years, when deeper lakes were drained, either steamengines or series of windmills placed at successive levels had to be resorted to. Thus at the time of the reclamation of

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the Beemster 49 mills were constructed, disposed as follows: 11 series of 4 mills each, I series of 3 mills, and I series of 2 mills. The work was commenced in 1608, when the dike was constructed, and the draining begun in 1612. The cost of this work amounted to $760,000, the total surface thus reclaimed being 17,720 acres.


Since the invention of the steamengine works of a greater magnitude were entered upon. Prominent among the latter is the draining of the Haarlem Lake. Originally there existed in this locality four small lakes, as the old maps of 1531 show us. In consequence of

successive storms, which caused the destruction of the adjacent peat lands, the four lakes merged into one, and the new lake thus formed became a source of much anxiety. With the increased surface exposed to the action of the winds, the waves on the lake became more powerful, and large sections of peat land were bodily swept away. The four lakes in 1531 covered an area of 22 square miles, but their surface nearly doubled in 1591, when they merged together. In 1647 they covered 56 square miles; in 1687, 60 square miles, and in 1848, 65 square miles, or three times their original area. When during a storm in the fall of 1836 the city of Leiden was flooded by the waters of the lake, the situation became untenable and the government decided to drain the lake.

Between the years 1840 and 1846 the lake was inclosed by a dike 37 miles in length. Three powerful engines were built of from 380 to 400 horse power each, the largest one of which operated eleven pumps each 63 inches in diameter and with a lift exceeding 15 feet. With the aid of these engines the lake, which averaged 14 feet in depth, was pumped dry during the years 1847 to 1852, exposing 42,000 acres of excellent arable

land, for with the removal of the peat by the storms the rich alluvial clay underlying the latter had been laid bare. The government has felt itself amply repaid for the enormous sum of $5,568,000 which was expended on this work. The sale of land yielded a revenue of $3,142800, and indirectly a great many incalculable advantages have been derived from it. (See map on preceding page.)

The last of the great works of this class that have been accomplished is the reclamation of the Ij, at one time an inlet of the Zuider Zee, and the construction of the large canal connecting Amsterdam with the North Sea. This work was completed in 1876 and the canal opened to navigation on November 1 of that year. Twenty-two square miles of excellent land were thus added to the kingdom. Space does not permit here of a description of the technical difficulties that were overcome in the construction of this magnificent canal, through which the largest sea-going vessels now pass daily on their way to and from Amsterdam.


Next to their use in reclaiming land covered by fresh water, the dikes have been of great importance in reclaiming land from the sea. The province of Zeeland, which occupies the southwestern corner of the Netherlands, is composed of a number of islands, conspicuous for their fine agricultural lands and for the thrifty populations which they support. The larger part of this province has been formed by the hand of man out of the numerous shoals, claybanks, and sandbanks that existed here centuries ago. The archipelago of Zeeland, as well as some of the islands situated to the north of it, lie scattered in the broad estuaries of the principal rivers, and are consequently entirely alluvial formations. The fine silt carried in suspension by the rivers was de

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posited, building up the claybanks little by little, until they became exposed at low water in the shape of mudflats.

As early as the year 1000 enterprising individuals had begun to build small levees along the edges of these flats, in order to prevent the tides from washing over them, and gradually there arose from out of this shallow body of water a number of islands, the nuclei of the present archipelago. As the banks became larger, built up by the river deposits, aided by artificial devices for catching silt, new dikes were built further out into the sea, and the islands grew slowly as piece after piece was added to them. (See diagrams, p. 226.)

The growth of these islands is an admirable illustration of the untiring and steadfast persistency so characteristic of the Dutch people; for the work of reclaiming land from the capricious North Sea was fraught with much danger and tribulation. Again and again during severe storms the sea broke through the dikes and invaded the land acquired with so much painstaking labor, and in several instances areas were irrevocably lost. It must be remembered that this land was obtained by draining the water from an exceedingly humid, clay-like soil. This drying-out process, for such it really was, entailed as a natural result a shrinkage of the solid materials, which

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