Page:The American Cyclopædia (1879) Volume VI.djvu/250

242 DRAINAGE operation of this class. From an area of 70 sq. m. of average depth of water of 12f ft., situated below the level of any sluices that could be constructed, it was required to raise the water an average height of 16 ft., and to an estimated possible amount of 35,000,000 tons in a month. An enormous steam engine was constructed in London for working 11 pumps of 63 in. diameter each and 10 ft. stroke, the maximum capacity of all which was to raise 112 tons of water 10 ft. at each stroke. These were set around the circular tower which contained the engine, and from the up- per portion of which the balance beams radi- ated, one for each pump. They raised in ac- tual work 66 tons per stroke, discharging the water in a large canal 38 m. long, and from 115 to 130 ft. wide. Two other similar engines were applied to the same work, and the pump- ing was continued from May, 1848, to July 1, 1852. Then the area was thoroughly drained. The entire expenses from the commencement of operations in 1839 to the close of 1855 were estimated at 748,445, which would be more than paid by the proceeds of the sale of the lands. The draining of the lake, however, in- creased a difficulty which will be appreciated by a consideration of the system of drainage in Holland. Along much of the seaboard of that country the waters of the ocean are kept from overflowing the land by immense dikes. The country is divided into several districts, called hydraulic administrations, each of which has three divisions of surface, viz. : natural lands, basins, and polders. The basins com- prise the marshes, lakes, canals, and drains, having one surface level, which is below high and above low tide, and connect with the sea by sluices furnished with gates, which open when the internal waters are higher than the external, and shut when they are lower. The polders are lands which lie below the sur- face of the waters in the basins, and can only be kept dry by pumping. The Rynland hy- draulic administration comprises 305,000 acres, which before the draining of Haarlem lake was divided into 76,000 acres of natural lands, 66,000 acres of basin, and 173,000 acres of polder lands; but since the addition of the lake to the latter, the basin covers only 11,500 acres, while the polder lands have an area of 217,500 acres. Now the basins are the res- ervoirs of the waters which are raised from the polders and also of the drainage from the natural lands. When the tides are regular, at every ebb they empty a portion of their contents, and thus maintain a capacity to receive the natural and artificial drainage until the next ebb ; but if by the action of the winds the ex- ternal waters are held at a higher level than those in the basins through the period of an ebb tide, a collection of water in the latter en- sues, and may come to equal their capacity. Before this occurs, however, the pumping from the polders must cease, for some space must be allowed for the natural drainage. At about DRAKE the mean level of the tides in the Zuyder Zee there is a mark upon a pile which is called the A. P., or Amsterdam pile, and which is the point of reference for regulating the height of water in the basins. There is also a mark for each administration, called the point of arrest. This point is not at the same level for all the administrations, some being allowed to con- tinue their pumping operations longer than others. If the water in the basins were al- lowed to become too high, there would be danger of the overflowing and breaking away of the dikes. It will therefore be seen that the area of the basins is an important matter. If it bears only a small proportion to that of the land to be drained, they soon become filled, and unless they can empty their contents into the sea, the drainage of the polders must cease, and consequently they will become overflowed. As the range of tide along the Dutch coast is about 6 ft., only a small range of rise and fall, or capacity, can be allowed for the basins, when their area bears so small a proportion to that of the drained lands as it does in the Ryn- land hydraulic administration since the drain- age of Haarlem lake has so greatly reduced the basin area. One circumstance has been taken advantage of in the work of draining, which is that the S. W. winds raise the level of the waters in the N". E. portion of the ba- sins so that they may continue to discharge their contents longer than they could if they remained level. The S. W. end of the Zuyder Zee, also, by having its water level depressed, can continue to receive the drainage from the lands longer than if the surface remained level. The wind, therefore, is utilized as a source of work or energy, which goes far to make up for the loss incurred by diminution of the area of the basins. The draining of Haarlem lake had become a matter of necessity more than of utility; for, as it lies in a peat formation of great depth, connected with other lakes, the barriers were constantly being washed away, which, by increasing the surface of the water, allowed the waves to become higher by the action of the wind ; and thus the surrounding country became subject to inundation. DRAKE, Daniel, an American physician, born in Plainfield, N. J., Oct. 20, 1785, died in Cincinnati, Nov. 5, 1852. His father emi- grated to Mason co., Ky., in 1788, where Dan- iel lived until his 16th year on a small farm. In December, 1800, with very little education, he was placed under the care of Dr. William Goforth of Cincinnati as a student of medi- cine, and in 1804 commenced practice. In 1816 he graduated at the university of Penn- sylvania, and in 1817 he lectured one session in the Transylvania medical school at Lexing- ton, Ky. In December, 1818, on his personal application, the legislature of Ohio granted a charter for the medical college of Ohio at Cin- cinnati, and also established there the commer- cial hospital. In the autumn of 1820 the for- mer institution was opened for students, and