SOIL 



germs, of insects, even of birds and the higher animals, live 

 upon it. To it return the dead leaves, the bodies of dead 

 insects, and waste products of all kinds. Within it, they 

 are broken to pieces and worked up again by the roots of 

 other plants in order to form new leaves, new insects, and 

 food for bird and beast. Just as in engine-works, you may 

 see old engines, wheels, and scrap-iron being smashed into 

 pieces ; they are melted down and again worked up into 

 engines of some improved design. 



On a chalk-clifF, which dates from the long-distant Cre- 

 taceous period, the entire thickness formed by the yearly 

 work of plants for millions and millions of years is often less 

 than a foot in depth, and probably only four to five inches 

 are true soil. 



But this is an exceptionally thin stratum, although it is 

 capable of producing rich turf, fat snails, and excellent 

 mutton. In peat-mosses and in those buried forests which 

 form the coalfields, vegetable matter may accumulate in 

 deposits of thirty feet of coal. Yet these stores of carbona- 

 ceous matter seem to be at first sight miserly and selfish, 

 at least jfrom a vegetable point of view. 



They resemble the gold and silver withdrawn from 

 circulation in the world by some Hindoo miser and buried 

 deep within the earth. Yet somebody is pretty certain to 

 find out and make use of such stores eventually. 



In the case of the peat and coalfields, an animal of 

 sufficient intelligence to utilize them has already been pro- 

 duced, and now they are used by man as fuel. 



It is very important to remember that the soil is a sort of 

 last home to which the particles of carbon, of nitrate, and 

 minerals always return after their wanderings in the bodies 

 of plants, of insects, or of other animals. They probably 



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