488 Scientific Proceedings, Royal Dublin Society. 
fallen 35 feet below its original level, forming a depression with a 
maximum depth of 28 feet. 
It is obvious that, before the outbreak, the condition of the 
bog was that of a viscous fluid enclosed within a resistant wall, 
The pressure of the fluid and the tension of the envelope were 
then in equilibrium. Owing to an increase in pressure or a 
decrease in the tensile strength of the containing wall, this 
equilibrium was destroyed, the envelope was ruptured at its 
weakest part, and the viscous fluid, under a head of pressure 
rushed down the inclined surface provided by the natural drainage 
of the country. 
Before entering further into the discussion of the causes which 
led to the outburst, it will be convenient to present here informa- 
ti onwe have collected concerning similar occurrences which have 
taken place in the past. We give first a list of those which have 
affected the bogs of this country; they are arranged in chronolo- 
gical order. 
Account oF Boe Fiows 1n IRELAND. 
A.D. 1697, June 7, Kapanihane Bog, Co Limerick, near Charle- 
zille-—This occurrence is so quaintly described in a letter dated 
June 7, 1697, that it is worth quoting verbatim et literatim :— 
“On the 7th Day of June, 1697, near Charleville, in the County 
of Limerick, in Ireland, a great Rumbling, or faint Noise was heard 
in the Earth, much like unto a Sound of Thunder near spent; for 
a little Space the Air was somewhat troubled with little Whisking 
Winds, seeming to meet contrary Ways: And soon after that, to the 
greater Terror and Afrightment of a great Number of Spectators, — 
a more wonderful thing happened; for in a Bog stretching North 
and South, the Harth began to move, viz. Meadow and Pasture 
Land that lay on the side of the Bog, and separated by an extra-_ 
ordinary large Ditch, and other Land on the further side 
adjoining to it; and a Rising, or little Hill in the middle of the 
Bog hereupon sunk flat. 
“This Motion began about Seven of the Clock in the Evening, 
fluctuating in its Motion like Waves, the Pasture-Land rising very 
high, so that it over-run the Ground beneath it, and moved upon 
