The universal geography : earth and its inhabitants

IRELAND. 389
enlarging their area, others grow smaller, and in the end disappear altogether,
although they receive the same amount of rain as before, and have not been drained.
Lakes of this kind are sucked up as it were by the vegetation by which they are
invaded. Bogs, or wet spongy morasses formed of decayed vegetable matter,
cover hundreds of square miles in Ireland, and frequently occupy the beds of
ancient lakes, as is proved by the heaps of fresh-water shells found at their
bottom. In many instances this process of displacement is still in course of
progress. The lakes invaded by the marsh plants grow gradually smaller until
they resemble wells, dangerous to the wanderer unaware of their existence.
Occasionally, too, the spongy mass pours forth a stream of mud. This happens
after heavy rains, which cause the bog to swell, until its coarse tissue of vegetable
matter is no longer able to resist the pressure exercised from below. The gases
shut in beneath the upper layers of turf then escape with a noise resembling that of a
volcanic explosion, and streams of water and liquid mud rush out through the open-
ing effected by them. One of these eruptions took place in 1821 in the peat bog of
Kinalady, near Tullamore, about the centre of the great plain. Rumbling noises
had been heard for some time from the bog, and its surface heaved like an agitated
sea, when at length a torrent of mud, 60 feet in depth, burst from a crevice,
overwhelmed the houses and trees that stood in its way, and spread itself over an
area of 5 square miles.* Sometimes calamities of this kind result from a want
of foresight on the part of peat-cutters. By removing the peat from the neigh-
bourhood of a lake, the rampart which retains the stiU liquid mass that occupies
the interior is sometimes weakened to such an extent as to be incapable of resisting
the pressure from within, and an eruption of mud is the result. The history of
Ireland abounds in instances of this kind. The wanderer who wends his way
across the bogs can tell at once when he is passing over a concealed lake, for
the soil beneath him quakes with every step he takes, and he feels as if he were
walking upon a carpet stretched out in mid-air.
The Irish bogs are amongst the most extensive in Europe, and even in the
veenen of the Netherlands we do not meet with such wide tracts of almost
deserted country, where mud cabins as black as the peat in the midst of which
they rise are rare objects. The bogs of Ireland cover an area of 4,420 square miles
that is, nearly the seventh part of the whole island, and in many instances they are
40 feet thick. Those spread over the great central plain have an average
thickness of 26 feet ;
but supposing the available peat throughout Ireland to have
a depth of no more than 6 feet, a reserve of fuel equal to 15,000,000,000 cubic
yards lies on the surface. Peat is largely used in the country for domestic purposes,
but cannot compete with mineral coal in factories.
The Dutch bogs naturally divide themselves into Jiooije veenen and hagc
veenen, and similarly In Ireland we have red bogs and black bogs, according
to the plants of which they are formed and their degree of moisture. The black
bogs, which supply nearly all the peat, occups' the plain and the deeper valleys of
the mountains. The vegetable matter of which they consist is undergoing gradual
* Jacob Noggerath, " Der Torf."
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