342 HOW CROPS FEED. 
Tkis fact is made evident by the following data furnish- 
ed by Peters. The soils employed were 
No. 1. Unaltered Soil. 
No. 2. Soil heated with hydrochloric acid for some 
time, then thoroughly washed with water. 
No. 3. No. 2, boiled with 10 grams of sulphate of lime 
and water, and washed. 
No. 4. No. 2, boiled with solution of 10 grams of chlo- 
ride of calcium, and well washed with water. 
No. 5. No. 2, boiled with water and 10 grams of car- 
bonate of lime. 
No. 6. No. 2, boiled with solution of bicarbonate of 
lime, and washed. 
Portions of 100 grams of each of the above were placed 
in contact with 250 c.c. of *|,, solution of chloride of po- 
tassium for three days. The results are subjoined: 
ssolv is 
Nistnber|\_ 1. Dissolned ‘by the souiion ee 
of soil. Lime. Magnesia. Soda. Chlorine. by the soil. 
Bec cega7 '| 0.0940 0.0084 0.0261 0.4482 0.1841 
“haere 0.0136 0.0004 0.4444 0.0227 
Ot ee 0.0784 0.0024 0.0019 0.4452 0.0882 
ae 0.0560 0.0094 0.0024 0.4452 0.1243 
Sirti tease 0.1176 0.0094 0.0019 0.4425 0.1378 
Woh othe I] 0.1456 0.0074 ars 0.4404 0.2011 
It is seen that the soil which had been washed with 
acid, absorbed but one-ninth as much as the unaltered 
earth. The treatment with the various lime-salts increas- 
ed the absorbent power, in the order of the Table, until 
in the last instance it surpassed that of the original soil. 
Here, too, we observe that the absorption of potash ac- 
companies and is made possible by the displacement of 
other bases, (in this case almost entirely lime, since the 
treatment with acid had nearly removed the others). We 
observe further that the quantity of chlorine remained 
the same throughout (within the limits of experimental 
error,) not being absorbed in any instance. 
Way first showed that the absorptive power of the soil 
— 
