348 Absorption of Potash by Soils of known Composition. 
agrees almost exactly with the amount of chlorine in 52'910 of 
chloride of potassium. Another proof is here given that the 
electro-negative portion of the chloride of potassium entirely 
passed through the soil, and the base of the decomposed salt 
alone was absorbed by the soil. 
Experiments No. 5 and 6. — On Calcareous Clays. 
The two following experiments were tried by Mr. Philips on 
soils from fields No. 7 and No. 12 of the Royal Agricultural 
College farm : — 
The solution of chloride of potassium was much stronger than 
that employed in the preceding experiments. In both experi- 
ments a solution containing '6617 per cent, of chloride of 
potassium was used. 3500 grains of each soil were shaken up 
in a bottle with 7000 grains of this solution of chloride of 
potassium. After a lapse of 24 hours, the greater portion of the 
liquid was filtered off perfectly clear, and the potash determined 
in a weighed quantity. 
The following results were obtained by Mr. Philips : — 
Experiment No. 5. — Soil from Field No. 7. 
Chloride of . . 
Potassium. Potash - 
Before filtration the solution (7000 grains) con "\4g-3i9 29-"l 
tained J • 
After filtration 18-207 = 11-487 
Difference 28-112 = 17-734 
Consequently 1000 grains of soil absorbed 5 "06 6 grains of 
potash. 
Experiment No. 6. — Soil from Field No. 12. 
Chloride of „ , , 
Potassium. Potash - 
, Before the experiment the solution contained 46 319 == 29*221 
After contact with soil 8-020 = 5-059 
Retained hy 3500 grains of soil .. 38-299 = 24-162 
1000 grains of soil thus absorbed 6-903 of potash. 
These filtration experiments, No. 5 and 6, show that soils 
absorb a much larger quantity of potash from a stronger solution 
of chloride of potassium than from a more dilute one. 
Experiment No. 7. — On Sterile Sandy Soil. 
In this and the next experiment 7000 grains of soil were shaken 
up with a solution of 104-55 grains of chloride of potassium in 8 
decigallons of water ; the liquid was drawn off after four clays, and 
analysed. 2 pints on evaporation gave a residue which, dried at 
300° Fahr., weighed 32-540 grains. 
