CARBONATE OF LIME. 115 



"Lime enriches the father, and the want of it impov- 

 erishes the son," we would be near the truth. In 

 England we read that while lime has been in use 

 there for many centuries, it has largely been in neg- 

 lect for the past forty years, and now there must be 

 a decided awakening and a renewed use of it or Eng- 

 lish soils will relapse most sadly. 



Forms and Kinds of Lime. — Eaw limestone is a 

 carbonate of lime. Burning it drives off the carbon 

 and makes it a quick, or caustic, lime. After burn- 

 ing, when it absorbs moisture and carbonic acid gas 

 again and becomes air-slaked lime, it has then less 

 causticity than when it was first burned. If it is 

 slaked with a little water, so that it falls into a dry 

 powder, it is caustic lime. If it is slaked and ground 

 in a factory it is called hydrated or agricultural 

 lime. It is sometimes ground without adding water, 

 when it is termed ground lime ; or the raw limestone 

 is ground into powder, which is called ground car- 

 bonate of lime, or ground limestone, or raw lime- 

 stone. 



Now, what of the virtues of these various forms of 

 lime? 



The burning drives off nearly half the weight of 

 the natural limestone; thus the resultant product is 

 nearly twice as strong as it was before burning. 

 Thus if it must be shipped a long way by rail it may 

 save so much in freight that it will be better to use 

 the burned lime. Burning has also made it biting 

 or caustic. A lump of this caustic lime held in the 

 hand and moistened will eat the flesh. Caustic lime 



