ABSORPTIVE AND RETENTIVE 
SdZ 
experiments carefully conducted, during the summer months, or during that period of the 
year when vegetation is affected by atmospheric changes. At any rate, experiments per¬ 
formed during the winter, the early spring, or late in autumn, would not be so satisfactory 
as during some portion of the period when vegetation is active and energetic. Experiments 
were commenced and pursued for a week or more, but they were suspended partly for 
want of time at command, and partly from the fact, that all the experiments and obser¬ 
vations appeared to lead to and establish the result, that the powers in question were in 
the direct ratio to the quantity of organic matter in the soil, though modified by its state of 
subdivision ; for it appeared, that when the subdivision was excessive, the soil absorbed and 
retained water in its maximum degree ; and when coarse, or but imperfectly divided, its 
power of absorption and retention were proportionally diminished : still it was evident, 
that even when the organic matter was coarse, those powers were much greater than when 
the soil was deprived of matter from the vegetable kingdom. The facts being established, 
that the power of absorption and retention are in the ratio of the quantity of organic matter, 
modified by its state or condition, it shows that soils may differ in those powers, even when 
by analysis the amount of organic matter is nearly the same. It becomes important, then, 
in a practical point of view, to secure a proper degree of fineness in the vegetable and 
animal matters which are added to soils, inasmuch as they will be much more effective 
as fertilizers in a given period than if they were coarse ; for it is during the dry season, that 
vegetables require a soil which is both absorptive and retentive. That soil which is ca¬ 
pable of seizing atmospheric water, and holding it when the atmosphere is heated, is one 
of the best constituted soils. 
The preceding observations, we believe, may be easily confirmed by other observers, if 
they will but turn their attention to the varieties of loam, or any of the mixtures of sand 
and organic matter, or organic matter and clay. 
Another fact, which is equally important with the foregoing, and which was determined 
while engaged in these experiments, is the order in which the different materials composing 
the soils stand to each other, or the relations which they severally hold to each other in 
their separate capacity. For example, it was observed that marls, or the finely divided 
calcareous compounds, are quite powerful absorbers and retainers of water, being even 
superior to clay and the argillaceous compounds, or to alumina in a state of great purity. 
This result was quite unexpected ; as the common and prevailing opinion is, and has been, 
that clays are the most active and energetic in their powers of absorbing and retaining 
moisture. 
In accordance, then, with these observations, we found that the materials which are 
most influential in soils, may be arranged in the following order, when their relations to 
water or moisture are considered: 1. Peat, or pure organic matter; 2. Marl, or, to be 
explicit and definite, freshwater or shell marl; 3. Clay, and argillaceous compounds in 
which this element is in excess ; 4. Loam, or the common soils as they usually occur ; 5. 
Sandy loam ; 6. Sand. Each of these kinds of earth is influenced, in its power of ab- 
