( 58 ) 



the posifioii of Ainsterdain is silu.aled. To lliis I was enal)le(l bv a 

 few cxpeiiiuenlal wells wliieli jMr. (I. van Rcjykn, l^t lieiiteiiant- 

 engineei-, cliai'ged willi tlie e.veeiilioii of IIjo works there, was kind 

 enough to lune iiia<lo for I lie |»iii-|»os(' of iliis ijivestiualiou. Al my 

 ])ro[)Osal seven of these exjieriniental wells were bored to various 

 depths in the middle of a meadow, about 'MM) metres south of the 

 Sloten road and the farm "Rustvrede", within a square of three 

 metres side. Under the lower end of the iron tubes which were 

 open below, gravel had been ponied to a depth of half a metre. 

 I>y examining the water that had risen in those lubes as to level 

 and com[)Osilion one ean ol)tain information about the state of aifairs 

 at various depths in relation \vith the eondilion of the soil. 



Letter Depth of the Layer in whieh the water 



of the layer of water is found, 



well. below the Held '). 



A 1 to 1.5 M. fen. 



A 1./ ,, 2.2 ,, ,, 



B 2.5 ,, :L0 „ Upper elay. 



C 5 ,, 5.5 ,, Layer (►f sand in the clay. 



C' 7.5 ,, 8.0 ,, Lower part of the elay. 



D 10 ,, 10.5 ,, Between deep fen and sand 



E 15 ,, 15.5 ,, Sand under the denser albnium. 



A well situated 30 metres to the west, 44 metres dee[), IV, 13, 

 was eompared with these experimental wells. 



Most of these wells were ready at the end of August ult. A' was 

 tijiished about the middle of Sei)tember, C' the 19'^' of October. The 

 level of the water and the amount of chlorine were repeatedly 

 examined by me. After all the wells had been left undisturbed as 

 long as November 20, the following state of affairs was found. 



Water level in M. -^ A.P. Chlorine 



in mg. per L.- 



A 1.465 135 



A' 1.495 202 



B 1.495 G17 



C 1.493 780 



C' 1.677 145 



D 2.720 124 



E 2.737 68 



IV, 13 2.747 92 



1) The level of the field is 1.33-^ A.P. 



