On the Chemical Froperlics of Soils. 
111 conclusion, tlic more prominent and practically intorestlnjj 
l)oints which have been developed in the preceding pages maj 
1)C briefly stated in the following 
Summary. 
1. All the soils experimented upon have the power of absorl)- 
ing ammonia from its solution in water. 
2. The sandy soil absorbed as much ammonia as the clay 
soil. 
o. The pasture land, and probably many other soils ricli in 
organic matter, retain less ammonia than soils in which organic 
matter does not occur in excess. 
4. The differences between sandy, calcareous, and clay soils, 
in their jiower of absorbing ammonia, is not so great as is gene- 
rally believed. 
5. Ammonia is never completely removed from its solution, 
however weak it may be. On passing a solution of ammonia, 
"whether weak or strong, through any kind of soil, a certain 
quantity of ammonia invariably passes through. No soil has the 
power of fixing completely the ammonia with which it is brought 
into contact. 
6. In the preceding experiments all the soils absorbed more 
ammonia from the stronger than from the weaker solution ; that 
is to say, the absolute quantity of ammonia which is absorbed 
by a soil is larger when a stronger solution of ammonia is passed 
through it. But, relatively, weaker solutions are more thoroughlv 
exhausted than stronger ones. 
7. Soils containing much organic matter (humic acids) at first 
•absorb less ammonia from weak solutions than others poor in 
"vegetable matter. But subsequently they take up more ammonia 
if it is presented to them in stronger solutions. 
8. A soil which has absorbed as much ammonia as it will 
from a weak solution, takes up n fresh quantity of ammonia Avhen 
•it is brought into contact with a stronger ammoniacal solution. 
9. All the soils not only absorbed free ammonia, but likewise 
removed a certain quantity from solutions of ammoniacal salts. 
10. In passing sulphate of ammonia or sal-ammoniac througii 
a soil, the ammonia alone is absorbed, and the acids pass through 
•in combination with lime or other mineral matters. 
11. A larger proportion of mineral matter is dissolved in a 
soil when dilute solutions of ammoniacal salts are filtered through 
it than is the case with pure water. 
12. Soils absorb more ammonia from stronger than weaker 
solutions of sulphate of ammonia and chloride of ammonium. 
13. Not only the strength, but likewise the quantity of the 
■ammoniacal solution which is brought into contact with a soil, 
