On the Chemical Properties of Soils. 
113 
Consequently '189 {grains of ammonia were removed from 
every 1000 grains of solution, or 2'64G grains from tlie whole 
solution ; 1000 grains of soil therefore absorbed '7543 grains of 
ammonia. 
Fourth Experiment, on Sterile Sanchj Land. 
100 parts of the soil, dried at 212° Fahr., contains : — 
Oxide of iron ami a little water of combination .. .. 5"36 
Oxides of iron and alumina _ 5"70 
Carbonate of lime '25 
Alkalies and magnesia "49 
Pliosphoric acid trace. 
Sulphuric acid 'OS 
Soluble silica I'Ol 
Insoluble siliceous matter (sand) ST'll 
100-00 
It will be seen that this soil hardly contains any lime and 
abounds in sand. It contains a good deal of organic matter, 
but very little clay, Avhich will be seen by the subjoined me- 
chanical analysis : — 
Organic matter O'SG 
Clay 4-57 
Lime "25 
Saud 89-82 
100-00 
3500 grains of this soil were mixed with 14,000 grains of am- 
monia solution and left to settle for three days, when the follow- 
ing results were obtained :— 
Before contact with soil 1000 grains of ammonia 
solution contained -332 
After contact with soil 1000 grains contained -. .. "063 
-2G9 
Consequently '269 grains were removed from every 1000 grains 
of solution, or 3-766 grains from whole solution. 
1000 grains of soil therefore absorbed 1-076 grains of ammonia. 
In a second experiment, in which the ammonia was deter- 
mined by a standard solution of test-acid, in the same manner 
as in the first experiment, 1000 grains of soil were found to 
have absorbed 1-136 grains of ammonia. 
In both experiments the solution, after remaining in contact 
w'ith the sandy soil, had a deep yellow colour. The caustic 
ammonia evidently dissolved a good deal of the organic matter of 
the soil. The ulmic and humic acids in the soil, in uniting Avith 
ammonia, form salts, which are soluble in water, and of a brown 
colour. A brown coloured solution thus indicates that some 
VOL. XXI. I 
