On the Chemical Properties of Soils. 19 



than from weak solutions, and that however weak the 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. I 

 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 parts : 



Ammonia. 

 Grains. 



Moisture 4'72 



Organic matter and water of combination 11*03 



Oxides of iron 9-98 



Alumina 6'06 



Carbonate of lime .. 12'10 



Sulphate of lime '75 



Alkalies and magnesia (determined by loss) 1'43 



Soluble silica (soluble in dilute caustic potash) .. .. 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 

 character. 



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 



,, No. 2 ,, 21-28 or -304 



,, No. 3 ,, 12-32 or -176 



,. No. 4 ,, 6*16 or -088 



In each experiment 7000 grains of the respective liquids were 

 repeatedly agitated in a tight-fitting glass-stoppered bottle, with 

 J Ib. 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. 



