68 TALKS ABOUT THE SOIL. 



soil is a sandy loam, because there are sixty-four parts 

 of the silicon oxide, forming sand. The clay, or alu- 

 minium oxide, forms only five parts in one hundred ; 

 and the calcium oxide, another five parts. The or- 

 ganic matter was probably the remains of dead plants 

 left in the soil from old crops. Twelve of the fourteen 

 elements were in the soil, and one of the rare elements 

 the manganese was represented by a small per- 

 centage. 



The chemists have also analyzed plants ; and it is 

 found, that, of the fourteen elements in soils, ten are 

 to be found in plants. These are carbon, hydrogen, 

 oxygen, nitrogen, sulphur, phosphorus, potassium, cal- 

 cium, magnesium, and iron. These the plant obtains 

 either from the soil or from the air. It does not find 

 any element, in either the air or soil, in a pure state ; 

 neither does the plant show them in a pure state in 

 itself. Naturally we might wonder if it is worth while 

 to remember these fourteen elements. If they cannot 

 be found in a pure state, why try to remember them? 

 Plants contain phosphorus. They obtain it from the 

 phosphorus in the soil. Suppose, now, we wish to 

 plant a crop in a certain field. The plants need phos- 

 phorus. Will they find it ready for use in the soil? 

 Perhaps they will, and perhaps they will not. Very 

 likely the plants that grew in this field last year, or the 

 year before, have taken up all the phosphorus that is 

 fit to use. There may be plenty there, but not in 

 shape for food. Our new plants, not finding it ready, 

 refuse to grow, and the crop will be a failure. If we 



