POWERS OF SOILS. 
353 
sorbing and retaining water, by the amount of peaty matter which it contains, subject to 
modification by its fineness. 
That it is the vegetable or organic matter contained and intimately combined in soils 
which give them in the main their powers, is supported by the fact, that when it is 
destroyed or removed by ignition, very little difference exists among them as it regards the 
powers in question. This statement is confirmed when experiments are made upon marl 
and clay first in their natural state, and afterwards when ignited. In the condition to 
which they are brought by this process, they differ but a trifle from each other, as it re¬ 
gards the amount of moisture they will absorb in equal times and under similar conditions. 
It seems, that after burning, the different kinds of soils are brought down to the same 
standard. Thus, in fifteen samples of soils selected from different districts, some of which 
were clay and sand, together with peat and marl, on being ignited, they absorbed nearly 
equal quantities of moisture in equal times : they at most differed only between one and 
two grains in the amount of water which they absorbed. Two hundred grains of soil were 
selected for these experiments : they were first moistened with water, till perfectly imbued 
with it, and, in four hours, they were weighed. This operation was repeated at equal 
intervals, for many times in succession, and always with the same results ; the peat, or 
nearly pure vegetable matter, scarcely losing any water in the course of a few hours, 
while sand would lose almost all its water, and become nearly dry. After they were 
ignited, however, they dried sensibly at the same rate ; or when left to absorb moisture 
after undergoing this process, the sand absorbed nearly as much water as the marl or clay, 
or the common soils which had been burnt. 
From the foregoing statements, it is evident that soils ought not to be subjected to the 
process of paring and burning, without special reasons. If there is no objection to burning, 
on the score of the loss of organic matter, together with a loss in its power of absorbing 
moisture, then the process will be followed with advantageous results ; for it is unques¬ 
tionably true that the mineral or organic matter is more soluble in consequence of having 
been ignited. Sandy soils, and all the varieties of loams, are rarely improved by burning. 
When all the vegetable matter is burned off, they must necessarily be injured. So, on 
the other hand, the addition of finely divided vegetable matters, if it served no other pur¬ 
pose in soils than to aid and assist in the absorption and retention of moisture, this purpose 
itself would be quite an important one, and worthy of being secured. Water, in due 
proportion, must always be regarded as one of the essential elements of a good soil : it is, 
as it were, the moving power. In this light it would be regarded, if it was merely the 
medium for transmitting nutriment through the body of the vegetable ; but it is important 
in other respects, and hence growing plants must have a supply, or else they will suffer 
or die, according to the degree in which they are deprived of this element. 
[Agricultural Report.] 
45 
