500 Scientific Proceedings, Royal Dublin Society. ; 
tends to bulge out like a bag down the slope, and finally bursts. 
He lays special stress upon the rapid bladder-like sveiee that 
sometimes precedes an eruption. | 
Noeggerath! says, if the felt-like covering of extensive bogs, 
highly strained by water and gas, suddenly breaks, mighty streams 
of mud pour forth. 
Kinahan’ has attributed some bog-slides to shrinkage cracks, 
formed during drought, and enlarged by the subsequent entrance 
of water. 
Klinge,? the latest investigator of these phenomena, propounds — 
an entirely new theory, and expresses views on the constitution of — 
peat bogs differing in some respects from those usually accepted. 
He labours to prove that the absorption of sub-aerial water, or the — 
development of large quantities of gas, are insufficient to account 
for the bursting of bogs. He regards mountain bogs as of two — 
different kinds, those which have grown in the uniform climate of — 
the western coast of Europe, characterised by a continual increase — 
in the degree of decomposition from their surface downwards, and 
those which have arisen under the influence of severe changes 
of climate; the latter consist of alternating layers more or 
less highly decomposed. The different layers have different 
saturation limits for water, and these limits once attained never 
alter. There is no vertical movement of water through a 
bog. ‘This view, the author asserts, stands in complete opposi- — 
tion to statements made by older writers as to the absorption 
by bogs of from 50 to 90 per cent. of their bulk of water. In 
support of his contention that peat bogs are impermeable, he — 
‘appeals to pools on their surface, often 5 to 10 feet in depth, 
separated by peat-walls only 3 to 5 feet thick, and yet with — 
water levels differing from each other by several feet. The — 
dome-like form of mountain bogs he regards as inexplicable, — 
unless a high capacity for water in conjunction with imperviousness — 
be admitted for the peat. Excessive rainfall accumulates in pools — 
on bogs, which are drained by surface channels. Pools only © 
occur on bogs near the wet western coast of Europe. The author 
1 Der Torf, 1875, p. 12. } 
2 Valleys in their relation to Fissures, Fractures, and Faults: London, 1875, p. 10. — 
3 Ueber Moorausbriiche, Botanische Jahrbiicher, Bd. xiv., 1892, p. 426. 
