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.—Raw 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 
mearly 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 
