124 
On the Chemical Properties of Soils. 
Experiment 7. 
The solution left in the bottle from Experiment No. 4 was 
drawn off as thoroughly as possible ; 7000 grains of solution 
No. 3, containing '176 grains of ammonia in 1000 of liquid, 
were then added, and after repeated shakings the whole was 
left to settle for four days. 
Ammonia. 
Grains. 
Before contact with soil 1000 grains of the mixed solutions'! .^^r- 
contained / 
After contact with soil 1000 grains of the solution contained "096 
•051 
Therefore "051 grains of ammonia were removed from every 
1000 grains of liquid, or "480 grains from the whole solution, 
and retained by 1750 grains of soil, which had already taken up 
'175 grains of ammonia from the weaker solution. 
Ammonia. 
Grains. 
1000 grains of soil thus absorbed from the weakest solution "100 
From the stronger solution "274 
•374 
Or in both experiments "374 grains were removed and retained 
by 1000 grains of soil. 
Thus in all cases much more ammonia was removed from 
the stronger solutions than from the weaker, and was retained by 
the soil in addition to the quantity previously absorbed from the 
weaker solution. Thus the total amount of ammonia absorbed 
by 1000 grains of soil was in — 
Ammonia. 
Grains. 
Experiment No. "> 1-687 
, , No, G -737 
No. 7 •374 
It will be observed that in Experiment No. 1, 1000 grains of 
soil removed 1*32 grains of ammonia from the strongest solution. 
The same solution, taken in the same quantity as in Experiment 
No. 1, and left in contact with soil which had already absorbed 
"64 grains of ammonia, removed an additional quantity of 1*047 
grains, or altogether 1*687 grains. 
It thus appears not only that the strength of the solution 
influences the amount of ammonia which can be retained by the 
soil, but likewise that the quantity of liquid which is passed 
tlirough a soil will affect the proportion which a soil is capable 
of abstracting from a given solution. 
From a large quantity of an ammoniacal lic[uid it appears to 
