or Lake of Haarlem, which has recently been drained, lay S.E. of the town, and was 14 miles long by 10 miles broad. It had been formed by an inundation in the end of the sixteenth century, which transformed four small lakes into one sheet of water, laid waste several villages, and destroyed much property. It continued gradually to gain upon the land, and in the beginning of the eighteenth century it covered an area of 45,000 acres. The people of Holland saw with much alarm the rapid extension of its boundaries, and at an expense of about L38,000 succeeded in partially arresting its progress; but the annual cost of repairs to the works of defense had for a considerable period amounted to between L3000 and L4000. Various schemes had been proposed for the drainage of the lake, but it was not till 1839 that effectual means were taken for that object. On the 9th of November 1836 a furious hurricane from the west had driven the waters of the lake upon the city of Amsterdam, and inundated upwards of 10,000 acres of low land in the neighbourhood; and on the 25th of December following another hurricane impelled the water in the opposite direction upon the city of Leyden, the lower parts of which were submerged during 48 hours, and 19,000 acres of land covered with water. The enormous loss occasioned by these two storms determined the government on the drainage of the lake. The first business was to dig a canal round the lake for the reception of the water, and to accommodate the great traffic which had hitherto been carried on by means of it. This canal was made 38 miles in length, 130 feet wide on the west side, and 115 feet on the east side of the lake, and 9 feet deep. All the inlets into the lake were then closed by large earthen dams; and various works were executed to facilitate the flow of water into the sea. These preliminary works occupied till 1845. To give some idea of the magnitude of the undertaking, it may be mentioned that the area of water enclosed by the canal was rather more than 70 square miles, and the average depth of the lake was 13 feet 14 inches. The water had no natural outfall, being below the lowest possible point of sluicage; and, including rain water, springs, &c., during the time of drainage, it was calculated that probably 100 million tons would have to be raised by mechanical means. After drainage too, the site could only be kept dry by mechanical power, so that the annual drainage might amount to 54,000,000 tons, to be raised on an average 10 feet, and it might happen that as much as 35,000,000 tons of this amount would have to be raised in one month. A gigantic steam engine of a peculiar construction, designed by Messrs. J. Gibb and A. Dean of London, was erected and found to answer the highest expectations. It could raise 112 tons of water at each stroke, and was capable of discharging 1,000,000 tons in 25½ hours; while the consumption of fuel was only one-sixth part of the average consumption of ordinary draining engines. To describe this vast bit of iron—It consists of two steam cylinders, one of 84 inches diameter placed within another of 144 inches diameter, both fitted with pistons, the outer being of course annular. The two pistons are united to a great cross head or cap, which is furnished with a guide rod or spindle—both pistons and cross-head being fitted with iron plates, and, together with parts of the engine attached, having an effective weight of nearly 90 tons. The engine-house is a circular tower, on the walls of which are arranged eleven large cast-iron balance-beams, which radiate from the centre of the engine. Their inner ends, furnished with rollers, are brought under the circular body of the great cap, and their outer ends are connected to the pistons of eleven pumps, each of 63 inches diameter; the stroke of both ends is 10 feet, and the discharge from the pumps is 66 tons of water per stroke. The action of the engine is very simple: it is on the high-pressure-expansive-condensing principle. The steam is admitted first beneath the small piston; and the dead weight of 90 tons is lifted, carrying with it the inner end of the pump balances, and of course allowing the pistons to descend in the pumps. The equilibrium valve then opens, and the steam in the cylinders passes round to the upper surface of the small and annular pistons, puts the former in a state of equilibrium, and presses with two-thirds of its force upon the annular piston, beneath which a vacuum is always maintained; thus the down stroke of the engine, and the elevation of the pump pistons and water, is produced by the joint action of the descending dead-weight in the cap and pistons, and the pressure of steam on the annular piston. The steam is expanded from six to eight times its original volume. The engine has two air-pumps of 40 inches diameter, and 5 feet stroke each. The total weight of iron employed for the engine-pumps, &c., is 640 tons; and the cost of the machinery and buildings was L36,000. The water is lifted by the pumps into the canal, from which it passes off towards the sea-sluisces. Two other engines of equal size and power were afterwards constructed by Messrs Harvey of Hayle and Messrs Fox and Co. of Perran, in Cornwall, the makers of the previous one. The pumping commenced in May 1848, and the lake was rendered dry by 1st July 1852.

The first sale of the highest lands along the banks took place on 16th August 1853, when 784 hectares brought in £75,000 florins, or 733 florins per hectare. A second sale took place the same month, when 1273 hectares were sold for £74,450 florins, or 583 florins per hectare. Six sales have subsequently taken place, so that now 12,634 hectares (31,218 acres) have been sold for 3,973,933 florins (£497,829). There are still (1856) 4200 hectares for sale, and 32 hectares reserved for villages; so that altogether 16,806 hectares, or 41,675 acres, have been re-claimed. The 12,643 hectares sold since 1853 have all this year produced their first or second crops.

The entire expense of drainage from 1839 to 31st December 1855 was 8,491,344 florins (£1,748,445), which it is calculated will be entirely covered by the price of the reclaimed land.