( 756 ) 



water is also foiiiid in the south-east corner of tlie Beenrister polder, 

 opposite Pnrmerend. 



On the whole west of the Haarleninienneer poldei', in wells not 

 great!}" exceeding»- 30 ^I. in depth, tlie underground water is equally 

 fresh as dnne-water, also at Heemstede and at Hillegoni and in some 

 of the shallow polders near Haarlem. At great depth, tiiere is in 

 those parts a considerahle increase in the quantity of chlorine. Near 

 the railwaystation of Vogelenzang, between the Leidsche \'aart and the 

 rail-road, at 1600 M. from the Haarlemmermeer polder, at a depth of 

 88M.~A.P., it amounted to 184.6 m.G. a Liter, it being only 35.5 m.G. 

 a Liter at 25 M. .' A. P. Near the villa Bennebroek, 650 M. from the 

 Haarlemmermeer i)older, 47 M. ^ A. P. deep, it contained 99.4 m.G., 

 and at a depth of 89 M., 245 m.G. chlorine a Liter; on Bosbeek, 

 in the parish of Heemstede, being only 440 lAI. from that poldei-, at 

 about 30 M. -^ A. P., 58 m.G. a L. Numerous instances may be 

 brought forward of the quantity of salt in the underground water 

 growing with its greater depth, and at a higher level, as one draws 

 nearer to the deep polders. A well-know]i tact is, that in consequence 

 of the flowing do\vn of the underground water from off the dunes, 

 the water of the neighbouring low-lands, up to quite a few kilo- 

 meters' distance, may be fresh. More considerable and noticeal)le at 

 greater distance however, is that down-flow deep in the ground. 

 Close to the steam-mill for the (b'aining of the land, in the Meer- 

 weiden near Velsen, at full \/.j K.M. from the dunes, the under- 

 ground water, 28 M. below A. P., contained 30.5 m.G. chlorine and 

 at 44 M. below A. P., ()5.4 m.G.; and even 1 K.M. more east, 

 within the precincts of the fort, in the western corner of the Zuid- 

 wijkermcer polder (S.L. -^ 2.40 M.), at 34 M. -f A.P., only 60 m.G. ; at 

 45 M. -T- A. P., on the other hand, 603 m.G. chlorine a Liter. In 

 the midst of the dunes themsehes the ground-w^ater seems to get 

 brackish only at about 150 M. below A. P. 



Of special significance is the fact, already stated above, that the 

 underground w^ater in the deep polders is growing Salter at a much 

 higher level. So at Eert-den-Koning, only 300 M. within the Haarlem- 

 mermeer polder, at 26 M.^ A. P., the underground water had 367m G. 

 chlorine a Liter. Similar conditions are generally prevailing tliere. That, 

 generally speaking, the higher percentage of salt cannot be attributed to 

 water from the canals ( "boezem w^ater"), so cannot have got in from the 

 surface, may in the first place, be proxed from the fact, that the 

 water in silallo^^■ [)olders, in many places, dowqi to considerable 

 depths is as })erfeclly sweet as that in the dunes, although one can 

 prove that there is \\o communictvtion with the dunes; in the second 



