uantity of |
| | | oxygen absorbed |
| | | by |
| | | 77.165 grains |
| | | of the moist |
| | | soil in 30 |
| | Tenacity | days, from 15 |
| | of the | cubic inches |
| | soils. | of atmospheric |
| | Pure clay, | air. |
| | 100. | Expressed in |
| | | cubic inches. |
+-----------------+|------------|-----------------|
|Siliceous sand | 0 | 0.24 |
|Calcareous sand | 0 | 0.84 |
|Light clay | 57.3 | 1.39 |
|Stiff clay | 68.8 | 1.65 |
|Heavy clay | 83.3 | 2.04 |
|Pure clay | 100.0 | 2.29 |
|Carbonate of lime | 5.0 | 1.62 |
|Humus | 8.7 | 3.04 |
|Gypsum | 7.3 | 0.40 |
|Garden soil | 7.6 | 2.60 |
|Soil from Hoffwyl | 33.0 | 2.43 |
|Soil from Jura | 22.0 | 2.25 |
---------------------------------------------------

The experiments detailed in the preceding table speak in a great measure
for themselves, and scarcely require detailed comment. It may be
remarked, however, that the columns illustrating the relations of the
soil to water are probably more important than the others. The
superiority of a retentive over an open soil is sufficiently familiar in
practice, and though this is no doubt partly due to the former absorbing
and retaining more completely the ammonia and other valuable
constituents of the manures applied to it, it is also dependent to an
equal if not greater extent upon the power it possesses of retaining
moisture. A reference to the table makes it apparent that this power is
presented under three different heads, which are certainly related to
one another, but are not identical. In the second column of the table is
given the quantity of water absorbed by the soil, determined by placing
a given weight of the perfectly dry soil in a funnel, the neck of which
is partially stopped with a small piece of sponge or wool, pouring water
upon it, and weighing it after the water has ceased to drop from it.
This may be considere