[lynde-Dupré] 



ON OSMOSIS IN SOILS 



135 



brought to about 100°C. in the oven and then placed over a burner 

 until decided ebullition took place. The liquid was allowed to cool 

 over night and was then decanted into a 2,000 c.c. cylinder. It was 

 allowed to settle in the cylinder for seven days. 



A cylinder was filled with liquid in a similar manner each day for 

 seven days. After seven days the liquid in the first cylinder was de- 

 canted from the sediment and evaporated down in an enamelled pan 

 in an oven at 110°C. 



Next day the liquid from the second cylinder was added to this 

 pan. This was continued each day for seven days. The liquid was 

 finally evaporated down until it was a rather thick syrup. 



MANOMETER- 



MERCURY— 



THERMOMETER 



— —^ —-SOIL SOLUTION 



DISTILLED WATER- Lj — H _ — — 



jœ&BzâËBZ^ZEBZZ Zc 



How the Apparatus Was Set Up. 



The apparatus used is shown in the figure above. Two glass 

 tubes approximately 15 cms. long and 1 cm. diameter were closed at 

 one end with one layer of cotton cloth. They were then filled with 

 the thick hot liquid, and placed in cups of the centrifuge. The cups 

 were filled with hot distilled water to the level of the liquid in the tubes. 

 The centrifuge was run at top speed for 15 to 30 minutes; the liquid 

 was then decanted from the sediment and replaced by fresh thick 

 liquid. This was continued until the sediment reached the desired 

 thickness or until the thick liquid was exhausted. The centrifuge 

 made 1,300 r.p.m. and the center of the column of sediment in each 

 tube|was 25 centimeters from the center of the axes of the centrifuge. 



