THE SOIL, THE PLANT, THE ANIMAL 3 



the plant becomes bigger. It grows. In other words,. 



the plant, by feeding on soil and air, is enlarged 



through growth. 



Elements of Plant and Animal Life. The ele- 

 ments that enter into plant and animal growth are 



the following: 



Iron, an element of universal use. All soils contain 

 it. 



Calcium, a yellowish metal, abundantly found in 

 limestone soils. 



Potassium, a whitish metal and soft. It is called 

 potash when united with oxygen. 



Sodium, soft and light, and when united with 

 chlorine forms ordinary salt. 



Magnesium, is white in color and a hard metal. 



Aluminum, looks like silver and is very hard. 



Silicon, a substance earthy in appearance and, next 

 to oxygen, the most abundant element in the 

 earth crust. 



Sulphur, associated with nitrogen in the protein 

 compounds. 



Phosphorus, soft and yellow, often lacking in cul- 

 tivated soils. 



Chlorine, a colorless gas which, when united with 

 sodium, forms common table salt. 



Hydrogen, the lightest known substance, a color- 

 less gas. United with oxygen it forms water. 



Oxygen, a colorless and abundant gas. One-fifth of 

 the air, one-half of the earth's crust, and 

 eight-ninths of the water of the world is 

 formed of it. 



