SOILS 25 



diminish in amount, while the sand and clay will not. 



Experiment. Take two wide-mouthed bottles ; 

 fill both nearly full of water. Into one put about 

 a teaspoonful of clay and into the other the same 

 amount of sand'; shake both bottles thoroughly and 

 set on table to settle (Fig. 20). It will be found 

 that the sand settles very quickly and the clay very 

 slowly. 



As the result of our three experiments we will 

 find something as follows : 



Sand is light in color, moist, coarse, not sticky, 

 settles quickly in water, and will not burn. 



Clay is darker in color, moist, very fine, quite 

 sticky, settles slowly in water, and will not burn. 



Leaf mould or humus is very dark in color, moist, 

 very fine, slightly sticky, and burns when placed in 

 the fire. 



Experiment. We now have knowledge and 

 means for making simple tests of soils. Repeat 

 the last three experiments with the garden soil. 

 We will find, perhaps, that it is dark in color and 

 some of it burns away when placed in the fire, there- 

 fore it contains organic matter or decaying vegetable 

 matter or humus, as it is called. This sample has 

 perhaps fine particles and coarse particles ; part 

 of it will settle quickly in water while part settles 

 very slowly, and it is sticky. Therefore we con- 

 clude that there are both clay and sand in it. If 

 we shake a sample of it in a bottle of water and 

 let it settle for several days, we can tell roughly 

 from the layers of soil in the bottom of the bottle 



