62 TALKS ABOUT THE SOIL. 



and it would be difficult to decide where the sand or 

 clay ever came from, or from what rocks it was origin- 

 ally formed. We must go to work in quite a differ- 

 ent way, and look at soils from still another side. 



When we begin to observe things about us, we see 

 an endless variety of objects in nature. The variety 

 of artificial things made from these natural objects is 

 equally bewildering. We have already seen that 

 every thing in the world is either organic or inorganic ; 

 and we know that there are many different classifica- 

 tions of things, as plants, animals, wooden things, and 

 cloth, paper, or metal things. There is still another 

 classification, and that is the classification by elements. 

 An element is a single thing that stands alone, and is 

 not made of any two or more things. Glass is not an 

 element, because it is composed of several things. 

 Pure iron is an element ; that is, we are not able to 

 divide it into two different things. Sulphur is an 

 element : it is one thing only. Water is not an ele- 

 ment, because it is composed of two elements. Salt 

 is not an element, neither is the air we breathe. Many 

 thousands of experiments have been made with all 

 the myriad things in the world ; and it is now known 

 that there are only about sixty-five separate single 

 things in the world, and these things are called 

 elements. 



The soil and subsoil of our fields and gardens are 

 composed of a great number of different things. 

 Chemists have examined these things, and tell us that 

 among them all they can find only fourteen of the 



