9. DYKES.

Holland includes some of the lowest land on the continent of Europe. To keep out the ocean from the sea-bound provinces, and prevent her acquiring territory which seems to be her own, immense dykes or ramparts of earth and stone are raised along the coast, so broad and strong as to prevent the water passing through them, and sufficiently lofty to bid defiance to inundation at high tide. The rivers in many parts of the country are quite as dangerous as the sea, and their waters require to be restrained in their channels by dykes nearly as extensive as the sea-dykes.

The first thing necessary in the construction of these bulwarks is, to secure a firm solid foundation, sufficiently strong to support the immense weight to be laid upon it; by ramming down the soil, and by laying a substratum of clay, or by driving in piles, when it is incoherent. Were the foundation weak and porous, the water would dissolve and undermine it, and the dykes sink down into a hollow.

The rampart itself is composed of earth, sand, and clay, which will bind most firmly. The face of the dyke is protected by willow twigs interwoven so as to form a sort of wicker-work, and the interstices are filled up with clay puddled to render it compact. This wicker-work is renewed every three or four years, and occasions a considerable consumption of willow boughs, which are cultivated to a great extent for this purpose. The dykes are frequently planted with trees, as their spreading and interlacing roots assist greatly in binding the earth together. The base is often faced with masonry, and protected by vast heaps of stones brought from a distance, and by rows of piles driven into the ground to form breakwaters to the fury of the waves; the upper part is covered with turf, and rises sometimes to the height of 40 feet.

"When seen only at one spot, they may probably not strike the merely cursory observer as very extraordinary; but when it is recollected that the greater part of Holland is fenced in by similar bulwarks equally massive and costly, they will appear wonderful." -I. W. C. The most stupendous of these embankments are the Dykes of the Helder (see Route IV.), and of West Cappel, at the western extremity of the island of Walcheren. The annual expense of keeping in repair each of them, alone amounts to 75,000 guilders (about 6,400l.); while the sum total annually expended throughout Holland in the repair of dykes and regulation of water-levels varies from 5,000,000 to 7,000,000 guilders (nearly 600,0007.). A special corps of engineers, called waterstaat, including among them many men of science, well skilled in the principles of hydrostatics, are employed entirely in watching the state of the waters and guarding against all accidents from irruptions, - a most important duty, upon which the national welfare, and, indeed, existence, of Holland may be said to depend. During the winter, they are stationed near those spots where danger is most to be apprehended, and magazines are erected, provided with the necessary stores and implements, so as to be ready at a moment's notice.

The winter is the season most liable to accidents, when it not unfrequently happens that long prevailing S. W. winds, acting on the surface of the Atlantic, drive an accumulation of waters round the north of Scotland into the German Ocean. If these are succeeded by very violent tempests blowing from the N. W., the effect is, to propel the sea with great violence southward through the British Channel: but the straits of Dover are too narrow to admit the augmented body of water readily to pass, and in consequence

it falls back upon the coast of Holland. At such moments the "tall ocean" may truly be said "to lean against the land," and the strength of the dykes alone preserves it from submersion. To guard against such an assault, the utmost energy, activity, and skill are required. Watchmen are posted day and night along the line of threatened attack, to give instantaneous warning if symptoms of weakness are anywhere observed in the ramparts; and workmen are appointed by the authorities to be in readiness in the neighbouring villages.

It may easily be imagined with what intense anxiety the rising tide is, at such times, observed. The accumulation of waters in the ocean causes them to ascend far above the ordinary high-water mark; and if they only surmount the top of the dyke so as to flow over it, its ruin is inevitable. When such a calamity is anticipated, the alarm bell is rung, and every man hastens to his post. With the utmost rapidity, an upper rampart is constructed upon the top of the dyke to keep out the waters. It is incredible in how short a time a bulwark of this kind is elevated; it is a race between the tide and the embankment. If the strength and solidity of the dyke be doubtful, and a breach be apprehended, large sheets of sailcloth or mats of woven straw and rushes are laid on the outside, in the same manner as a leak is sometimes stopped in a ship. This prevents the earth's being washed away by the action of the waves. If all this be ineffectual, a course is pursued exactly similar to that employed in defending a breach made by artillery in the wall of a besieged fortress. A semicircular rampart is thrown up behind the part of the sea-wall which has shown symptoms of weakness, so that if the outer work be forced, an inner barrier, nearly as strong, stands ready prepared to resist the attack. It must be remembered that the works, raised at such an emergency, vast as they are, are only temporary, and are removed whenever the danger is past. Instances are not rare in which these precautions have proved quite ineffectual; and whole districts have been overwhelmed and lost for ever in the sea, or in the Rhine and its branches. greater part of the space now occupied by the Zuider Zee was dry land down to the XIIIth century. The Gulf of Dollart, in the province of Groningen, was the result of the inundation of 1277, which swallowed up 44 villages. Similar calamities have several times produced the same effects in that province. Even so late as 1717, 1560 habitations disappeared beneath the waters of the ocean, which had broken its bounds. The Biesbosch, near Dordt, and the sandbanks near South Beveland, called Verdronken Land (drowned land), are two other examples of submerged districts.

The

The annals of one province (Friesland), however, present the most extraordinary series of disasters from the ocean, and these, better than any thing else, will serve to show by what an unstable tenure the Dutch hold the land.

"Friesland was inundated in 533, 792, 806, 839, 1164, 1170, 1210, 1221, 1230, 1237 (this year the island called Vlieland, i. e. Lake-land, or land retrieved from the water, was formed), 1248, 1249, 1250 (the consequence of this inundation was a pestilence, which destroyed several thousand persons), 1277 (this year the Gulf of Dollart was formed). In 1287 the Zuider Zee assumed its present extent and shape, and 80,000 persons lost their lives in the inundation. 1336, 1400, 1421, 1429, 1516, 1524 (three inundations in this year), 1530, 1532, 1559, 1570. On Nov. 1. an inundation occurred which covered even the heights called Wieren, and cut off, in different parts of Holland, 100,000 persons, 30,000 of whom were Freislanders. From this year the inundations are less frequent; as an improved method of constructing the dykes was then introduced by the Spanish governor Robles,

who, at the same time, passed a law that they should in future be kept up by the owners of the land. Those recorded since 1570, were in 1610, 1675, 1717, 1776, and Feb. 5. 1825." Gauthier, Voyageur dans les Pays-Bas.

If the extraordinary elevation of the sea fall out simultaneously with a sudden thaw, or occur after long-continued heavy rains, inundations even more serious arise, in the interior of the country, from the rivers bursting their embankments. "In the winter of 1808-9, a violent tempest from the north-west had raised the waters of the Zuider Zee some feet above the highest mark of the spring-tides, and the waves beat with unusual violence against the dykes constructed to break their fury. The thaw on the Upper Rhine had increased the quantity and the force of its waters, which brought down masses of ice fourteen feet in height, and more than half a mile in length; to which the embankments, softened by the thaw, and somewhat injured, presented an insufficient barrier. A breach made in one part scon extended itself, and the torrent quickly covered the country, bearing before it by its force the villages, the inhabitants, and the cattle. The height of

the Zuider Zee prevented the water from finding an outlet; and it consequently remained on the ground for a long period, in spite of the exertions of the surviving inhabitants. By this event more than seventy houses were totally destroyed, a far greater number irretrievably damaged; and of 900 families, more than 500 were rendered utterly destitute. More than 400 dead bodies were left on the borders of the current; and at the city of Arnheim, 500 persons, mostly women and children, with many hundred head of cattle, were rescued from a watery grave by the hazardous heroism of the inhabitants, who ventured in boats to their rescue. - Jacob's Travels. The winter of 1824-5 was one of the most calamitous to the country known for many years. Amsterdam itself was threatened from the great height of the tides, which rose far above the usual level. The 1st of February, 1825, was a day of great anxiety: had the sea continued to rise a quarter of an hour longer, the dyke must have been overflowed, and, perhaps, have given way, and Amsterdam would have suffered a calamitous inundation. Fortunately, in a moment when the danger was greatest, the tide stopped, and the great pressure was immediately diminished and removed from the sea-wall: but the lower part of the town had already been laid under water. The injuries done at that time in the province of Holland were immense; but by Dutch industry all the damage was repaired within two years. The arms of one of the united provinces is a lion swimming, with the motto, Luctor, et emergo, "I strive, and keep my head above water." It might be generally applied to the whole country, which has to maintain a perpetual struggle for existence against difficulties never to be entirely removed. The inhabitant of the provinces bordering on the sea, or the Rhine, constantly threatened with the danger of submersion, is not more secure than he who dwells on the side of Etna, or at the foot of Vesuvius, with a volcano heaving beneath him. A stranger can only have a full impression of this when he walks at the foot of one of those vast dykes, and hears the roar of the waves on the outside, 16 or 20 ft. higher than his head. The expense of maintaining the dykes is supported by taxes levied by commissioners appointed for the purpose.

10. CANALS.

Holland is so intersected with canals, that to a person looking down upon it from a balloon, they would have the appearance of a network extending from one end of the country to the other. They serve, 1st, as the means of

communication; every little town and village having its own system of canals, which connect it with all the places around. 2dly, as drains to carry off the superfluous water of the country. 3dly, in the place of walls and hedges: fields, gardens and houses, are surrounded by canals or moats, as, in other countries, by fences; and they afford an equally good protection,

The canals differ considerably from those of England, which are measured out so as barely to admit two narrow barges to pass, and interrupted at short distances by locks. In Holland, as the canal is the drain as well as the highway of the country, and rids the land of its superabundant moisture, there is no restriction to its breadth; and as there is little variation of level, few locks are required: but those canals which empty themselves into the sea are provided with sluice-gates to prevent the influx of the tides, which are often higher than the waters of the canal itself.

The principal canals are 60 ft. broad and 6 ft. deep. Not only the surface, but even the bottom, is frequently higher than the adjoining land. The North Holland ship canal is truly one of the marvels of the country, and should be viewed by every traveller who visits Amsterdam. In its dimensions, it is not only the largest in Holland, but in Europe. (Route III.) Botany. The botanist will experience in Holland a pleasure more peculiarly his own, in meeting with some of the rarer plants of the English flora. The beautiful Menyanthes nymphæoides floats in the greatest profusion on the waters of the Dutch canals; and a plant of still more unfrequent occurrence, the Senecio paludosus, is occasionally to be detected on the banks. In general, throughout Holland, he will find the vegetation similar to that of his own country.-D. T.

11. POLDErs.

Polder is the name given to a piece of ground below the level of the sea or river, which, having been once a morass or lake, has been surrounded by embankments, and then cleared of the water by pumps. So large a part of Holland and Belgium was originally in the condition of morass, that whole districts are composed entirely of polders partitioned off by dykes or ramparts; and the ground thus drained is usually remarkable for its richness and fertility.

This

To drain one of these morasses, or inland seas, and render it fit for cultivation, the first operation consists in damming it in with a rampart of earth sufficiently strong and high to prevent the water from flowing into it. being done, windmills are erected on the edge of the dyke, each of which works a water-wheel. Pumps are very seldom used in draining, as, owing to the friction, they are only suited for drawing water from very great depths, such as mines. The instruments employed are, the scoop-wheel, the screw of Archimedes, and the inclined scoop-wheel, or Eckhardt wheel. When a great undertaking of drainage is going on, houses are erected in a convenient situation on the dyke, where the engineers and a committee of the proprietors constantly reside, and carefully watch the progress which their obedient workmen, the windmills, are making. In most cases the undertakers are compelled by government regulations to complete the drainage at a certain period of the year; for the very obvious reason that, if the ground were not cleared of the water until the beginning of the summer heat, the exhalations would materially increase the marsh fevers, which generally prevail in the first years of an extensive drainage.

"As the mills drain the water from the marsh, they empty it into a canal, opened on the other side of the dyke, which conveys it to a river or to the

sea. But most frequently the whole of this great operation cannot be performed at once; and, where the marshes are of too great a depth below the surrounding country, two or three dykes and as many canals are made, at different levels, rising by degrees to the upper canal, in which the whole terminates. In the Schermer-Meer, for instance, there are four stages of canals. Every piece of ground forms a long parallelogram, is separated from the next by a broad deep ditch, which, in reality, is a first canal. It serves to convey part of the harvest; to carry off the water which, but for this, would continue on the ground; but, above all, as an enclosure, which renders it unnecessary to guard the flocks, which seldom attempt to pass over this obstruction. The canals communicate, by means of the above-mentioned mills, with those of the second stage along the roads; lastly, two or three upper canals traverse the whole of the polder, like great arteries, carrying all these lower waters into one grand canal made below the dyke, and immediately connected with the sea. Nothing can be more curious than the sight of these masses of water, situated side by side, on four different levels. In general completely separated, they are made to communicate whenever it is desired, and the precise proportion which is thought necessary may be established between them. This girdle of windmills, which announces at a distance the frontiers of the polder, has the appearance of sentinels placed to guard the entrances; and Don Quixote would have been quite at home among them.

"It is easy to conceive the extreme fertility acquired by land managed in this manner. Formed originally of mud, which was itself rich, it is covered almost all the year round with herbs which contribute to its fertility. All the water which might be injurious is drawn off at pleasure, by means of the mills, and a regular and gradual irrigation is introduced at the most favourable

moment.

"The appearance of the polder itself, when you have got into it, is very different from the upper country; and though more remarkable, it is decidedly less agreeable. Each object reminds you that you are at the bottom of a lake, on a factitious soil, where every thing is calculated. When the draining is finished, the undertakers have very regularly portioned out the conquest they have made from the waters; they have divided and subdivided it into perfectly equal parts; they have dug canals, made roads, planted trees in perfect right lines, proscribed all curves, all variation in the distance, and placed at the head of each farm a square habitation, which is always similar to its neighbour. Very accurately surrounded with twenty trees, often fine, but never graceful, these redoubts resemble neither farm-houses, which would be less carefully kept, and more animated, nor country seats, where something could be dedicated to pleasure. Their large roofs, coming down nearly to the ground in four equal slopes, rest upon brick walls, which are always neat but never elegant. They look as if they had just sprung up like mushrooms among the tufted grass which surrounds them, and which seems never to have been trodden under foot."— A Journey in North Holland.

The better class of polders, with a good soil, when richly manured, and carefully cleared of weeds, especially those recently redeemed from the sea, are of great value, and highly productive as arable land; but the greater part furnish pasture or hay for the cattle, and are by no means of inferior value in this grazing country.

Many polders are subjected to annual inundations in the winter time, which, however, do no harm, if the water which covers them be not salt, and