Oil the Chemical Properties of Soils. 121 
tlian IVoiii weak solutions, and that however weak tlie solution 
may be, the total amount of ammonia which it may contain is 
never wholly absorbed by the soil, it appeared to me desirable 
to place these facts beyond a doubt by further experiments. 1 
therefore instituted a fresh series, in which one and the same soil 
was used throughout. This soil was found, on analysis, to contain 
in 100 j)arts : — 
Ammonia.. 
G rains. 
Moisture 4-72 
Orj^nuic matter and water of combination 11"03 
Oxides of iron 9'98 
Alumina 6'OG 
Carbonate of lime 12"10 
Sulphate of lime '75 
All^alies and maj^nesia (determined by loss) 1'43 
Soluble silica (soluble in dilute caustic potasli) .. .. 17"93 
Insoluble siliceous matter (chiefly clay) 36'00 
100-00 
An inspection of the analysis shows that this soil contains 
a good deal of clay and of carbonate of lime. It is in fact a 
calcareous clay, of a moderately stiff and retentive physical 
cliaracter. 
Four solutions of caustic ammonia in distilled water were 
carefully prepared : — 
Grains of Ammonia Per 1000 
per Gallon. Grains. 
Solution No. 1 contained 44-38 or '634 
, , Xo. 2 , , 21-28 or -304 
, , Ko. 3 , , 12-32 or -17G 
, , No. 4 , , 6-16 or -088 
In eacb experiment 7000 grains of the respective liquids were 
repeatedly agitated in a tight-fitting glass-stoppered bottle, with 
^ lb. of soil. The liquid was then allowed to subside for four 
days, after which time it became perfectly clear. The ammonia 
in the clear liquids was then determined by the process described 
in the preceding pages, and the following results were ob- 
. tained : — 
1. — Experiment with Solution No. 1. 
Ammonia. 
Grains. 
Before contact with soil the solution contained .. .. 4*438 
After contact .... 2-128 
2-310 
Therefore 2-310 grains of ammonia were absorbed by 1750 
grains of soil, or 1000 grains absorbed 1*32 grains of am- 
monia. 
