98 LIME. 
process of purifying lime, or depriving it of the acid 
with which it is combined, is by burning. This is done 
in a large kind of furnace, called a kiln, where the 
limestone and fuel are heaped in alternate layers. After 
it has gone through this process it is called quicklime^ 
and has the above-mentioned appearance and qualities* 
The uses of lime are numerous and important. The 
principal of these is in the formation of mortar, or 
cement for buildings. For this purpose it is first slaked, 
by having water poured upon it: a violent heat is there- 
by excited, and the lime falls into powder: it is then 
formed into paste by working it with water and sand. 
This, when dry, becomes extremely solid, hard, and 
durable. Various examples might be mentioned of 
buildings nearly two thousand years old, where the lime 
is, at this day, as hard as the stones which it cements 
together. Lime is also used for agricultural purposes : 
when spread upon land it is supposed to hasten the dis- 
solution and putrefaction of all kinds of animal and 
vegetable substances, and to impart to it a power of 
retaining the moisture which is necessary for the vigor- 
ous growth of corn or grass. It is employed in the 
refining of sugar, in the manufacture of soap, in the 
melting of iron, and by tanners, in a slate of solution, 
for dissolving the gelatinous parts of skins, and remov- 
ing the hair from them. The manufacturers of glue 
mix it with that article, for the purpose of adding to its 
strength, and preventing its becoming flexible by the 
absorption of moisture. This mineral, if well dried, 
pounded, and mingled with gunpowder, in the propor- 
tion of one pound to two, is of great utility in the rend- 
ing of stones and rocks : the mixture, it is said, will 
cause an explosion equal in force to three pounds' weight 
of gunpowder. Lime, if swallowed or inhaled, is a vi- 
rulent poison. Kence persons employed in lime-works 
are subject to very distressing complaints ; and hence, 
if bread be adulterated with lime, it is extremely injuri- 
ous. Notwithstanding this pernicious quality, lime is of 
considerable use in medicine. It is chiefly given in a 
