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said, and the quantities retained by the mixedmass of these earths being proportional to therespective quantities of each, it should seemthat in fertile soils, where the fall of rain is from20 to 30 inches, this power should not exceed70, nor fall short of 50 per cent. It were ofgreat consequence to settle this point with pre-cision; but to do this would require morenumerous experiments. To explain my mean-ing, I shall give one example.

Of the retentive Power of the Fertile Soils ,mentioned by Mr. Bergman.

This soil contains, as we have already seen,

56

14

30

Silex

Argill

Calx

Now the retentive power of 100 parts.Silex = 25Argill = 250Calx = 50

Consequently the retentive power of56 parts Silex = 1314 - Argill = 35

30 - Calx = 15

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