100 THE NATURE STUDY COURSE. 



some of the lye and vinegar and test the mixture with the 

 litmus paper. You may succeed in making a neutral liquid. 



Peaty soil in which water has been standing does not yield a 

 vigorous growth of cultivated plants. Sometimes it seems to 

 smell sour. Lay a bit of blue litmus paper between two moist 

 lumps of it. If the paper reddens acidity is proved. Such soil 

 should be sweetened, in other words, rendered neutral or 

 slightly alkaline. Infer from the experiment the effect of 

 scattering ashes or lime over sour soils. Soils that in some 

 parts of the country have borne many crops of vegetable 

 matter, and that have had little rain to leach off the ash 

 equivalents, have become very alkaline. The best soils are 

 either neutral or slightly alkaline. 



Heavy and Light Soils. — The farmers call sandy soils light 

 and clay soils heavy. Weigh a fruit-can full of dry sand, 

 empty and refill it with dried clay. Which weighs heavier 1 

 This experiment shows us that it is not the weight of the soils 

 that gives them these names. Roll some wet sand into a 

 marble; roll a bit of wet clay into a marble. When the 

 marbles are dry or nearly so which breaks up more easily? 

 Which is easier to dig or hoe in — sand or clay? These 

 experiences show us why the farmers call sandy soils light 

 and clay soils heavy. Studying the marble of clay may teach 

 us that we should not work clay soils when they are wet. 



Rub some clay into a gem jar of water ; shake it well, then 

 add some lime and observe the result. Recover the clay by 

 sedimentation and after it has dried to the proper consistency 

 make another marble. Infer the effect that lime has upon the 

 stickiness of wet clay soils. 



Drainage. — Review experiments, or make new ones to 

 supplement observations, to determine the value of drainage. 

 When the cold early-spring waters are drawn off warm rains 

 and warm air fill into the soil and impart their heat to it 



