THE AMMONIA OF THE SOIL. 247 
solved out nearly one-half the ammonia which the earth 
at first absorbed. 
The 1st dilution removed from thesoil ..............- 0.010 
Qa wt i AES (ES CRN rigs sratusle Se See 0.009 
“ 3d ss ss ES SSM oN, sicctaraletalavais ave’ ore 0.014 
“« 4th & - MEG Sean seaneeauwes 0.011 
“ 5th  “ ee BE) UO ORES a oe ade Glyn mee s 0.009 
MOtal 6 seiiasesesguisciendeses say ina aewses 0.053 
Deducting 0.053 from the quantity first absorbed, viz., 
0.112, there remains 0.059 part retained by the soil after 
five dilutions. Knop, in 11 decantations, in which the 
soil was treated with 8 times its weight of water, removed 
93°|, of the ammonia which the soil had previously ab- 
sorbed. We cannot doubt that by repeating the washing 
sufficiently long, all the ammonia would be dissolved, 
though a very large volume of water would certainly be 
needful. 
Causes which ordinarily prevent the Accumulation of 
Ammonia in the Soil.—The ammonia of the soil is con- 
stantly in motion or suffering change, and does not ac- 
cumulate to any great extent. In summer, the soil daily 
absorbs ammonia from the air, receives it by rains and 
dews, or acquires it by the decay of vegetable and animal 
matters. 
Daily, too, ammonia wastes from the soil—by volatili- 
zation—accompanying the vapor of water which almost 
unceasingly escapes into the atmosphere. 
When the soil is moist and the temperature not too low, 
(its ammonia is also the subject of remarkable chemical 
transformations. Two distinct chemical changes are be- 
lieved to affect it; one is its oxidation to nitric acid. This 
process we shall consider in detail in thenext section. As 
a result of it, we never find ammonia in the water of or- 
dinary wells or deep drains, but instead always encounter 
nitric acid united to lime, and, perhaps, to magnesia and 
alkalies. The other chemical change appears to be the 
alteration of the compounds of ammonia with the humus 
