a source is, however, so far as
the writer is informed, unknown to any extent in this country. We might
distinguish as _leaf-muck_ the leaves which have decomposed under or
saturated with water, retaining the well established term leaf-mold to
designate the dry or drier covering of the soil in a dense forest of
deciduous trees.

_Salt-mud._--In the marshes, bays, and estuaries along the sea-shore,
accumulate large quantities of fine silt, brought down by rivers or
deposited from the sea-water, which are more or less mixed with finely
divided peat or partly decomposed vegetable matters, derived largely
from Sea-weed, and in many cases also with animal remains (mussels and
other shell-fish, crabs, and myriads of minute organisms.) This black
mud has great value as a fertilizer.

4. _The Chemical Characters and Composition of Peat._

The process of burning, demonstrates that peat consists of two kinds of
substance; one of which, the larger portion, is combustible, and is
_organic_ or vegetable matter; the other, smaller portion, remaining
indestructible by fire is _inorganic matter_ or _ash_. We shall consider
these separately.

a. _The organic or combustible part of peat_ varies considerably in its
proximate composition. It is in fact an indefinite mixture of several or
perhaps of many compound bodies, whose precise nature is little known.
These bodies have received the collective names _Humus_ and _Geine_. We
shall employ the term _humus_ to designate this mixture, whether
occurring in peat, swamp-muck, salt-mud, in composts, or in the arable
soil. Its chemical characters are much the same, whatever its appearance
or mode of occurrence; and this is to be expected since it is always
formed from the same materials and under essentially similar conditions.

_Resinous_ and _Bituminous matters_.--If dry pulverized peat be agitated
and warmed for a short time with alcohol, there is usually extracted a
small amount of _resinous_ and sometimes of _bituminous_ matters, which
are of no account in the agricultural applications of peat, but have a
bearing on its value as fuel.

_Ulmic_ and _Humic acids_.--On boiling what remains from the treatment
with alcohol, with a weak solution of carbonate of soda (sal-soda), we
obtain a yellowish-brown or black liquid. This liquid contains certain
acid ingredients of the peat which become soluble by entering into
chemical combination with soda.

On adding to the solution strong vinega