( 750 ) 



iin(lei',G:i'Onnd water is submitted, is liroken l»y those local irregularities 

 of the geological structure. 



That we have not to thijik of strong currents of the deep under- 

 ground water, in a general direction for all, but of currents, dependent 

 on the local form of the surface, may tinally be confirmed by 

 soundings in two wells, sunk also under the direction of Dr. Klein, 

 in tlie Watergraafsme'^r [tolder (Summer Level r o.5() M.). One of those 

 wells, in the north of that polder, near the Ooster-railway, at 250 

 jNI. north-west of the so called Poort, deep about 39.5 M. t- A.P., 

 had oil June 18^'^ 1903 a level of 3.215 M. ^ A. P. In another, 

 presumi]igly 35 M. -! A. P. deep, in the south of that polder, near 

 the Omvali the level was 3.125 M. ^ A.P., on June 23'' 1903. The 

 latter lies 5 K.M. almost straight east, from that near the "Huis de 

 Vraag," which in its turji lies 2.3 K.M. east, but a little towards 

 the north, from well 111. 40, in the Rieker polder. 



Another Avell, about 25 M. ^A.P. deep lies, in the south-west 

 corner of the Bijlmermeej- [)older (Summer Level ~ 4.80), at 4 K.M. 

 north-west of the well near the Oostzijdschen Water-mill, 4.8 K.M. 

 south-east of thai near the Onnal and 11 K.M. from the Bullen- 

 wijkei- and Holendrechter polder (Summer Le\el^3.35 M.). This 

 well had, under the same meteoi-ological conditions, a level of 3.075 

 M. ^ A.P. At the well-known boring done by the corps of military 

 engineers, at Diemerbrug. near the Weesp turn])ike, beyond the 

 northern extremity of the Bijlmermeer pf»lder, the level of the water 

 in the well, then' 73 M. ^ A. P. deei), was 2.51 -f A.P. on Oct. 18^»! 

 1888. That well was 2 K.M. from the eastern border of the Water- 

 graafsmeer polder. 



Consequently the result of the ditferejit observations is, that there 

 is not a general, so called "artesian' current from east to west 

 or vice versa, in the i-egion between Amsterdam and the H. M. 

 polder, neithei' south-east of Amsterdam: those found, are but special 

 currents originating in local diiferences of height of the surface and 

 directed towards the Haarlemmermeer- and adjacent other deep i)olders 

 and towards the Watergraafsmeer-, the Bijlmermeer- and the Holen- 

 drechter ])olders. 



Another result is the c()iiclusioii we may di-aw, as to the dii-ection 

 of the vertical motion of the undei'ground watei-, hy comparing the 

 dilferent levels of the Avater in the deej» wells with that of the 

 Aarying levels of the undei-ground water I'ising b'om smaller (le[)lhs 

 and with the highest level this reaches. In short in the shallow 

 polders, in the dunes and iji the area between them, the tlireclion 

 appeal's to be downward ; in the deep polders, on the other hand, 



