SECTION XX. LIME 



CHALK is one form of lime. Another form is quicklime, 

 which consists of large lumps, from which bricklayers 

 make their mortar. If a bricklayer pours only a small 

 amount of water on a lump of quicklime, the lump absorbs 

 the water and falls into a powder. This lime that has 

 been slacked or changed into a powder by water is the 

 form generally used when the farmer employs lime as a 

 fertilizer. He buys the quicklime and lets it slack or 

 absorb water after it reaches the farm. 



Lime overcomes sourness of soils. All of these forms 

 of lime are alkaline, that is, the opposite of acid. Quick- 

 lime is more alkaline than the other kinds of lime and 

 fresh-slacked lime ranks next. If either of these forms of 

 lime is placed in contact with an acid, the lime unites with 

 the acid and by forming a substance different from either, 

 that is, neither alkaline nor acid, it destroys the acidity. If, 

 therefore, lime is put on sour soil, it unites with the acids 

 that made the soil sour, changing them into harmless 

 substances. 



How to know that a soil is sour. A doctor cannot w^ll 

 cure sickness until he determines the nature of the disease. 

 When he has done this, he knows what medicines to give. 

 Likewise it is important for the farmer to know the condi- 

 tion of his soil. If sourness is the principal trouble, lime 

 will aid some crops to grow much better on this soil. To 



