THE ELEMENTS OF SOILS. 63 



sixty-five elements. Occasionally three more are 

 found, but the quantities to be met with are very 

 small. We shall not be able to find more than one or 

 two of these elements anywhere in a pure state, unless 

 we visit the chemist's laboratory where they may be 

 kept in small quantities for various uses in the arts. 

 We shall not be able to find these fourteen elements 

 in a pure state in the soil. Some of them we cannot 

 see, touch, taste, or smell. Some of them are very 

 common, others are comparatively rare. If we wish 

 to know about the soil and its materials, we must here 

 be introduced to these fourteen elements, in order to 

 understand how they behave, and how they are related 

 to each other. 



i. Oxygen. This is a gas that we can neither see, 

 taste, nor smell. It is the most abundant element in 

 the world. It forms one-half of all the rocks and 

 soils, eight-ninths of all the water, and one-fifth of the 

 atmosphere. It is sometimes sold in iron tanks, as a 

 gas, for making the lime-light. In soils it combines 

 with many elements to make compounds that appear 

 to be very different. It combines with iron to make 

 oxide of iron, that gives the red color to so many 

 soils. It combines with another element to make 

 white sand, that forms the larger part of all sandy 

 soils. It is a greedy element, and is ready to unite 

 with any element that comes near it. So greedy is it, 

 that heat and light appear when it unites with some 

 other elements, and we call this eager combination 

 flame or fire. Animals cannot live without oxygen, 



