114 NATURE TEACHING 



small bottles, and kept as a record and for future 

 reference. 



This method gives interesting, and approximately 

 accurate, results, and is within the capacity of the older 

 pupils of a school class. For the method of procedure 

 where great accuracy is required, see such books as 

 Wiley's Agricultural Analysis, Vol. I. For junior classes 

 it is sufficient to omit the weighing and to make approxi- 

 mate separations by washing. 



Water in Soils. 



Place in separate glass funnels, supported over cups 

 or tumblers, equal weights of sand, clay and garden 

 mould ; these should be dry and coarsely powdered. 

 From 50 to 100 grammes is a convenient quantity. 

 Place a small piece of blotting-paper (or filter-paper) at 

 the bottom of the funnel to prevent the soil from getting 

 into the neck. Shake and tap the funnel gently to cause 

 the contents to settle down closely. Now pour equal 

 measures of water on the contents of each funnel, using 

 enough water to soak the soil thoroughly and to allow 

 water to drain through into the vessels placed beneath. 

 Observe that the water flows away with different rapidity 

 in the three cases, and that when all the water which 

 will drain away has been collected, the three different 

 kinds of soil retain different amounts of water. 



The funnels with their contents may be weighed 

 before the water is added, and again after it has drained 

 away. The difference between the two weighings gives 

 the weight of water retained in each case, and the results 

 should be recorded for the different kinds of soil, cal- 



