The gas that bubbles up through the water of a peat-bog, especially if the decomposing matters at the bottom be stirred, consists largely of marsh gas and nitrogen, often with but a small proportion of carbonic acid. Thus Websky found in gas from a peat-bed
Carbonic acid 2.97 Marsh gas 43.36 Nitrogen 53.67 ------ 100.00
Carbonic acid, however, dissolves to a considerable extent in water, and is furthermore absorbed by the living vegetation, which is not true of marsh gas and nitrogen; hence the latter escape while the former does not. Nitrogen escapes in the uncombined state, as it always (or usually) does in the decay of vegetable and animal matters that contain it. Its loss is, in general, slower than that of the other elements, and it sometimes accumulates in the peat in considerable quantity. A small portion of nitrogen unites with hydrogen, forming ammonia, which remains combined with the humic and other acids.
ON THE AGRICULTURAL USES OF PEAT AND SWAMP MUCK.
After the foregoing account of the composition of peat, we may proceed to notice:
1.--_The characters that adapt it for agricultural uses._
These characters are conveniently discussed under two heads, viz.:
Those which render it useful in improving the texture and physical characters of the soil, and indirectly contribute to the nourishment of crops,--characters which constitute it an _amendment_ to the soil (_A_); and
Those which make it a direct _fertilizer_ (_B_).
A.--Considered as an amendment, the value of peat depends upon
_Its remarkable power of absorbing and retaining water, both as a liquid and as a vapor_ (I):
_Its effect in promoting the disintegration and solution of mineral ingredients, that is the stony matters of the soil_ (III): _and_
_Its influence on the temperature of the soil_ (IV).
The agricultural importance of these properties of peat is best illustrated by considering the faults of a certain class of soils.
Throughout the State of Connecticut, for instance, are found abundant examples of light, leachy, hungry soils, which consist of coarse sand or fine gravel; are surface-dry in a few hours after the heaviest rains, and in the summer drouths, are as dry as an ash-heap to a depth of several or many feet.