92 



SOILS: PROPERTIES AND MANAGEMENT 



general principle, but a special apparatus is employed by 

 means of which the various grades obtained by sedimenta- 

 tion are siphoned off instead of decanted. The cylinder is 

 really a modified Wahnschaffe cylinder, 1 such as was 

 used in early soil analyses for drawing off the various 

 suspensions except that the siphon is placed outside the 

 cylinder instead of inside. 



The cylinder (die Schlammapparat) 

 as used by Atterberg is about 25 cen- 

 timeters high, with a glass pedestal 

 and a ground glass stopper. It is 

 graduated at 5, 10, 15, and 20 cen- 

 timeters upward from the bottom. 

 The same distance is divided also 

 into 16 divisions at the left of the 

 first graduation. The latter gradua- 

 tion is used in the separation of the 

 clay (Schlamm), so that the height 

 of the sedimenting column may be 

 regulated according to the time 

 available for the settling process. 

 An outside siphon, 4 to 5 milli- 

 meters wide, is attached to the cylin- 

 der at the bottom for the drawing 

 of the liquid when the sedimenta- 

 tion is complete. The top of this 

 siphon is opposite the 5-centimeter 

 mark on the cylinder. Cylinders 

 of this size are used only for the separation of particles 

 below .2 millimeter in diameter; for larger particles a 

 somewhat taller cylinder is used, with a siphon of the 



1 Wiley, H. W. Agricultural Analysis, pp. 205-207. Easton, 

 Pa. 1906. 



Fig. 14. — Atterberg's 

 silt cylinder for the 

 mechanical analysis 

 of soil by subsidence. 



