55 
Dr MacCulloch on Peat. 
of any given mass of peat may be presumed from other circum- 
stances. These are, chiefly, its alternation with beds of clay or 
alluvium, and the degree in which it approximates in its chemi- 
cal qualities to brown coal or bituminized wood. The latter 
change requires a length of time greater than that during which 
the greater number of the superficial ,peat-mosses of this country 
has existed ; and, in most cases, the alluvia which have been 
generated by the deposits of rivers are evidently of a very high 
antiquity. 
Under the various circumstances in which peat is found, it 
exists, as a soil, in various states, namely, in that of a fibrous 
and spungy mass, a powdery substance, a compact body, and a 
semifluid paste. The former condition occurs in all cases 
where the process has not been perfected, and presents infinite 
varieties. The second state is peculiar to mountain or drained 
peat. Compact peat, again, forms the predominant variety, in 
Scotland at least, as far as the mere bulk of the deposit is con- 
cerned ; although the drier kinds occupy a much wider extent 
of surface. The semifluid state occurs, not only in transported 
peat, but in other cases where it has been formed in lakes or 
marshes, which, from their forms, have the power of retaining 
water. Time consolidates even this peat, by filling the cavity 
with solid matter, and thus gradually excluding the water ; but it 
may continue for a long period in that state, as it does peculiarly 
on the continent of Europe. The well known inundations of 
fluid peat, have arisen in these particular cases, from the failure 
of the barrier by which such a cavity was bounded. 
It is not within the limits of this paper, to notice the capacity 
of these several kinds of peat for receiving agricultural improve- 
ment, nor the various well known methods by which they may 
be brought into cultivation. It must, however, be obvious, 
that no general rules can be applicable to the whole, and 
that the great diversity of qualities possessed by this substance, 
indicates corresponding differences of treatment. It is also evi- 
dent, from watching' the natural processes by which peat is con- 
verted into soil, that pulverization forms the essential part of 
every mode of treatment. In draining a compact peat, art thus 
imitates what nature effects on mountain declivities ; and, in 
mixing earths with it, the same results follow, which, in nature^ 
