MANUAL OF GENEBAL AGEICULTUEE. 15 



until the next meeting. The muddy appearance of the 

 water is due to the clay, which remains in suspension. 

 Siphon off without disturbing the sediment and keep both 

 the siphoned portion and the residue. Fill the beaker 

 again with water, stir, let settle an hour and siphon as 

 before. Repeat until after standing an hour the water 

 above the sediment is clear. Add the siphoned portion to 

 that obtained before. Transfer the sediment to the flask 

 containing the sand. Nearly fill with water and stopper 

 well. Shake and invert on a ring-stand so that the neck 

 is perpendicular. After the small particles have settled, 

 note the different layers of sand at the bottom, to fine silt. 

 Ascertain approximately by volume the percentages of 

 sand, silt and clay. 



11. WATER HOLDING CAPACITY OP SOILS. 



Materials: Air-dry sand, clay, loam, three student 

 lamp chimneys, cheesecloth, string. 



Tie a piece of cheesecloth over the bottom of a chim- 

 ney, moisten the cloth and weigh accurately. Fill the 

 chimney with dry sand and compact by dropping onto a 

 book a counted number of times from the same height. 

 Weigh it again and stand it in a trough containing sev- 

 eral inches of water. Leave it in this position until the 

 surface of the sand becomes thoroughly moist. Remove 

 the tube, wipe dry, and weigh again. Cover the tube with 

 cotton and set it where the water will drain away. "Weigh 

 later in the day and at each meeting of the class there- 

 after for at least 5 days. In the same way prepare tubes 

 using clay and loam or any other soil. 



If the soil used is very dry there should be no capil- 

 lary moisture, but the hygroscopic moisture is still in the 

 samples, hence the results will be too low. For more 

 accurate results the hygroscopic moisture should be deter- 

 mined. Express your results in tabular form. 



Questions: 1. Which soil loses water more rapidly? 

 2. Which takes the longest time to percolate? 



