( 753 ) 



from tlie low-tido lino, I>eiii,U' 2.5 M. ; 1200 M. heyoiid tluit lijie, 

 5 M. hclow A. P. — and that the fine-gTaiiied sand intermixed with 

 cday of the original npperlayers for a great pait \y\\] have been 

 rephiced bv coarser sea-sand, must considerably have contributed 

 towards greatly increasing the pression-tall of the deep underground 

 Avater, at tiie sea-side. At high-tide the flowing o(f however is very 

 small, and all things considered, the flowing off of the water from 

 the dunes, at the polderland side, certainly will not be less consideral)le 

 than that towards the sea. 



But let us drop this subject, too few facts being at our dis[)osal 

 to Judge of that complicated pi-ocess, and watch the influence of the sea- 

 Avater at a greater distance fi'om the coast. There can exist no doubt 

 as to the underground of our low-lands being soaked with sea-water. In 

 none of the borings executed in the last scores of years, if oidy deep 

 enough carried through, the i)roof of it was laclving; more or less deep, 

 according to circumstances, but the underground water showing an ever 

 increasing quantity of salt, highly exceeding that of all })olders ditches 

 oi' canals, exceeding even that of the Zuiderzee. In or near the dunes, 

 one inust go much deeper to find sea-water, than in the polders; 

 and in the |)olders, on higher ground, as a rule, deeper than in those 

 lower situatcfl. In the Brouwerskolkje, at a depth of 72 M. -7- A.P., 

 the percentage of chlorine did not exceed that of surface dune- water, 

 neither was this the case in wells of the Harlem water-works, deep 

 .54M.^-A.P.; nor in the one, in the dunes at Elswout, 80 M. -f A.P. 

 dee[) ; nor in the Rieker polder at more than 50 M. ~ A. P. Near 

 the Hnis-de- Vraag, in the north-east corner of the Rieker polder, 

 down to 82.5 M. t- A.P. only 34 m.G. chlorine a Liter was found; 

 at 46.5 M. -f A.P. iu)t moi-e than 81 in.G. ; and near "Het Kalfje", 

 on the Amstel, south (»f Amsterdam, at 31 M. ^ A.P., only 47 m.G. 

 a Liter. At Purmerend, situated in shallow polders, with Summer 

 Levels of 1.25 to 1.60 M. ^ A.P., but surrounded by the deep 

 Purmer- (Summer-Level ^ 4.47 M.), the Beemster- (S.L. -^ 4.00 M.) 

 and the Wijdewormer polder (S.L. -7- 4.50 M.), the water rising from 

 50 M. ^ A.P., has a quantity of oidy 43 m.G. of chlorine a Liter. The 

 well-water at Schermerhorn, in shallow i)olders, het\veen the deep 

 Beemster- and Schermer polders, at 76 M. -f- A.P. deep, contains 170 

 m.G. chlorine a Liter. Although the underground watei- in those 

 deep polders, on the whole is brackish, the quantity of chlorine 

 was only 192 m.G. a L. in the Purmer polder, at about 1 K.M. 

 from the encircling dike, in the direction of Purmerend on the Wester- 

 weg, and 600 M. north the church. Similar fresh deep underground 



50* 



