230 



The National Geographic Magazine 



has been maintained there by the Dutch 

 Government since 1772. In order to 

 derive the greatest possible use from 

 the data so obtained, all the gage rods 

 in the kingdom are referred to the same 

 baselevel, mean high water, generally 

 denoted by the symbol AP, and the 

 heights of water thus indicated by them 

 give directly the elevation of the water- 

 levels with respect to that of mean high 

 water of the sea. 



The present kingdom has an area very 

 nearly equal to the combined areas of the 

 States of Connecticut and New Jersey. 



Connecticut 4,99° square miles. 



New Jersey 7,815 square miles. 



Netherlands 12,738 square miles. 



About 59 per cent of this area con- 

 sists of alluvial formation, and is in- 

 closed by dikes and provided with arti- 

 ficial drainage. There are, therefore, 

 about 7,515 square miles of lowlands, 

 very nearly equivalent to the area of the 

 State of New Jersey, while the remain- 

 ing highlands would cover an area about 

 equal to that of the State of Connecticut. 

 The discharge of the Rhine at the point 

 where it enters the country is similar to 

 that of the Tennessee River, while the 

 flow of the Meuse may be compared with 

 that of the Potomac. 



SMAI.L AVERAGE RAINFALL IN THE 

 NETHERLANDS 



As a large part of the Netherlands is 

 drained artificiall}^, a few words concern- 

 ing the rainfall will be of interest. The 

 country enjoys the unenviable reputa- 

 tion of possessing a wet soil and a still 

 wetter atmosphere. Both of these attri- 

 butes are popular exaggerations. The 

 atmosphere of the Netherlands is fre- 

 quently moist — that is, it contains at 

 times a high relative humidity — but the 

 rainfall nevertheless is moderate, not to 

 say small. As compared with the United 

 States, it will be found that the amount 

 of precipitation that occurs annually in 



the Netherlands is about the same as 

 that of the Great Plains region. The 

 normal precipitation for the Nether- 

 lands, as derived from observations ex- 

 tending over more than a century, is' 

 about 26 inches per annum, or only 5 

 inches more than half of the amount of 

 rain that falls annually in Washington, 

 D. C. ; and, in spite of the reputed 

 moist atmosphere of the Netherlands,, 

 the evaporation during the early sum- 

 mer months exceeds the precipitation. 



Table of Evaporation and Precipitation from 

 Observations Made at Zwanenburg, near 

 Amsterdam, Dnritig ly^j-iS^j* 



Months. 



Jantiary. . . . 

 Februar}'.. . 



March 



April 



May 



June 



July 



August 



Septeinber . 

 October. . . . 

 November . 

 December. . 



Total 



o g- 



Inches. 

 1.49 

 1.46 



1-43 

 1.49 

 1.56 

 2.09 

 2.69 

 2.97 

 2.82 



3-09 

 2.76 

 2.03 



25.5 



9 » 



Inches. 

 0.33 

 0.57 



1-37 

 2.39 

 3.26 



3-74 

 3-74 

 3-25 

 2.16 

 1.24 

 0.70 

 0.53 



23.28 



Excess— 



8.18 



5.58 



In other words, there is a decided dry. 

 season, during which droughts are by 

 no means uncommon. In order to keep 

 the water in the ditches at the proper 

 level, to prevent plant-growth from suf- 

 fering during such droughts, an efficient 

 remedy is found in allowing the water 

 in surrounding bosoms and canals to run 

 back into the polders, and the usual pro- 

 cess of their maintenance is thus actu- 

 ally reversed. 



The polder lands known as Rijnland, 



* From A. A. Beekman, Nederland qls Pol- 

 dei4and, p. 100. 



