16 Practical Farming 



How Bacteria which are agents of corrosion, dissolving the 

 Work in the g^-j g^ ^^i^x it is carried by the rivers in 

 solution and deposited elsewhere. The work 

 of these invisible plants is of the greatest importance 

 to the tiller of the soil; for it is through their agency 

 that the materials used by other plants are again reduced 

 to their component parts, so that they can once more be 

 used by crops. Thus goes on the constant round of nature, 

 using over and over again the same elements. 



The same water that has flowed to the 

 epetition ^^^ -^ j-gt^j.j^g(j ^^y ^j^g clouds in rain, and 

 in Nature -' ' 



thus keeps up vegetation on the earth and 



through it the animal life as well. The radiant energy of 

 sunshine acting on the green leaves of plants enables 

 them to get and store away in their tissues the carbon from 

 carbon dioxide. Year after year the tree grows, storing 

 carbon away and locating the energy of the sunshine 

 where it can again be turned into active energy. We cut 

 the tree into firewood and bum it, and get back the 

 radiant energy of the sunshine in the heating of our houses 

 and the driving of our steam engines. In the same man- 

 ner the coal accumulations are simply the stored-up 

 energy of the sunshine of long past ages, and we get the 

 same radiant energy when we use it for heating or the 

 driving of the locomotive. We bum it, and the carbon 

 dioxide goes back to the air to furnish food for other plants, 

 so that the ceaseless round of nature is kept up. We 

 destroy nothing in this world. What we call destruction 

 is simply the resolving of matter into original and simple 

 states ready to make other combinations and to appear in 

 even more useful and beautiful forms. The various cur- 



